assignment 4

SECOND EDITION FOUNDATIONS OF PHYSICAL

ACTIVITY AND PUBLIC HEALTH

Harold W. (Bill) Kohl, III, PhD University of Texas

Health Science Center at Houston University of Texas at Austin

Tinker D. Murray, PhD Texas State University

Deborah Salvo, PhD Washington University in St. Louis

Library of Congress Cataloging-in-Publication Data Names: Kohl, Harold W., III., 1960- author. | Murray, Tinker Dan,

1951-author. | Salvo, Deborah, 1983- author. Title: Foundations of physical activity and public health / Harold W.

Kohl, III, PhD, University of Texas at Austin, Tinker D. Murray, PhD., Texas State University, Deborah Salvo, PhD, Washington University in St. Louis.

Description: Second edition. | Champaign, IL : Human Kinetics, [2020] | Includes bibliographical references and index.

Identifiers: LCCN 2019027467 (print) | LCCN 2019027468 (ebook) | ISBN 9781492589976 | ISBN 9781492592822 (epub)

Subjects: LCSH: Exercise. | Public health. | Health promotion-- methods.

Classification: LCC GV481 .K548 2020 (print) | LCC GV481 (ebook) | DDC 613.7/1--dc23

LC record available at https://lccn.loc.gov/2019027467 LC ebook record available at https://lccn.loc.gov/2019027468

ISBN: 978-1-4925-8997-6 (print)

Copyright © 2020 by Harold W. Kohl, III, Tinker D. Murray, and Deborah Salvo

Copyright © 2012 by Harold W. Kohl, III, and Tinker D. Murray

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CONTENTS

PREFACE ACCESSING THE WEB RESOURCE ACKNOWLEDGMENTS

PART I    INTRODUCTION TO PHYSICAL ACTIVITY AND PUBLIC HEALTH

1         FUNDAMENTALS OF PUBLIC HEALTH

Defining Moments in Public Health

Areas of Specialization in Public Health

Core Functions of Public Health

Public Health Law

2         FUNDAMENTALS OF KINESIOLOGY Kinesiology Subdisciplines and Exercise Training

Principles of Exercise Training, Prescription, and Planning

Applying Physical Activity and Exercise Training Principles

Health and Fitness Benefits of Physical Activity and Exercise

3         INTEGRATING PUBLIC HEALTH AND PHYSICAL ACTIVITY

History of Physical Activity and Public Health

Role of Physical Activity in Chronic Disease Development

From Science to Practice and Back

Promoting Physical Activity for Health

Practitioners of Physical Activity in Public Health

4         MEASURING PHYSICAL ACTIVITY Evidence-Based Recommended Levels of Physical

Activity for Health

Laboratory Measures of Energy Expenditure

Electronic Devices to Measure Physical Activity

Direct Observation Techniques

Self-Report Instruments

Surveillance in Populations

Combining Measurement Approaches

PART II   HEALTH EFFECTS OF EXERCISE AND PHYSICAL ACTIVITY

5         CARDIORESPIRATORY AND METABOLIC HEALTH

Prevalence of Cardiovascular Disease

Risk Factors for Cardiovascular Disease

Kinesiology and Cardiorespiratory Health

Cardiorespiratory Fitness Assessments

General Recommendations for Cardiorespiratory Health

Prevalence and Economic Costs of Metabolic Disease

Metabolic Disease Risk Factors

Kinesiology and Metabolic Health

Common Tests of Metabolic Function

General Recommendations for Metabolic Health

6         OVERWEIGHT AND OBESITY Caloric Balance

Prevalence of Obesity and Overweight and Associated Health Consequences

Obesity and Overweight Risk Factors

Obesity and Overweight Challenges

Kinesiology and Body Weight

Common Assessments of Obesity and Overweight

Physical Activity Guidelines for a Healthy Weight

7         MUSCULOSKELETAL AND FUNCTIONAL HEALTH

Prevalence of Musculoskeletal Disorders and Related Health Challenges

Risk Factors Associated With Musculoskeletal Disorders and Associated Health Challenges

Kinesiology and Musculoskeletal Health

Common Tests of Musculoskeletal Fitness or Function

Physical Activity and Musculoskeletal Health

Functional Health

Risk Factors for Poor Functional Health

Common Tests of Functional Health

Fitness Recommendations for Functional Health

8         CANCERS Prevalence of Cancers

Cancer Risk Factors

Kinesiology and Cancers

Physical Activity Among Cancer Survivors

Physical Activity Guidelines for Cancer Prevention

9         BRAIN HEALTH Prevalence and Economic Costs of Brain Health

Disorders

Common Brain Health Conditions

Risk Factors Associated With Brain Health Disorders

Physical Activity and Brain Health

Physical Activity and Brain Cognitive Function

Physical Activity Guidelines for Brain Health

10      HEALTH RISKS OF EXERCISE AND PHYSICAL ACTIVITY

Musculoskeletal Injuries

Kinesiology and Musculoskeletal Injuries

Sudden Adverse Cardiac Events

PART III STRATEGIES FOR EFFECTIVE PHYSICAL ACTIVITY PROMOTION

11      INFORMATIONAL APPROACHES FOR PROMOTING PHYSICAL ACTIVITY

Understanding the Community Guide

Rationale for Informational Approaches

12      SCHOOL-BASED APPROACHES TO PROMOTING PHYSICAL ACTIVITY

Rationale for School-Based Physical Activity Programs

Kinesiology and Physical Activity Outcomes for Youth

School-Based Physical Activity and Physical Fitness Assessments of Youth

Physical Activity in Children and Adolescents

International and National Trends in Youth Physical Activity Levels

School-Based Physical Education

Developmental Considerations for Physical Activity in Youth

13      BEHAVIORAL AND SOCIAL APPROACHES TO UNDERSTANDING AND PROMOTING PHYSICAL ACTIVITY

Behavioral Theories and Theoretical Models of Behavior Change

Social Support for Health Behavior Change

Individually Adapted Health Behavior Change Programs

Socioecological Model of Behavior

Social Support Interventions in Community Settings

14      ENVIRONMENTAL AND POLICY APPROACHES TO PROMOTING PHYSICAL ACTIVITY

Access

Urban Design

Measuring the Built Environment

Physical Activity Policy

Land Use Policy

Co-Benefits of Activity-Promoting Environments and Policies

15      PROGRAM AND POLICY EVALUATION FOR PHYSICAL ACTIVITY AND PUBLIC HEALTH

Ways to Measure Program and Policy Effectiveness

Logic Models for Physical Activity Promotion and Policies

Evaluation Designs

Data Collection and Analysis

Disseminating Results

16      PARTNERSHIP DEVELOPMENT AND ADVOCACY

Key Factors in Building Partnerships

Strategies for Physical Activity Advocacy

GLOSSARY INDEX ABOUT THE AUTHORS

PREFACE

Welcome to Foundations of Physical Activity and Public Health, Second Edition. This text is a collection of the concepts that define the emerging field of physical activity and public health. Much like the more established fields (i.e., the effects of nutrition and smoking on public health), physical activity and public health has its roots in the grafting of two other fields. In this case, public health scientists and exercise scientists have come together to create an opportunity to improve health through research and promotion of physical activity. Methods and evidence from the public health sciences (epidemiology, health promotion, behavioral science, and environmental health) and kinesiology (exercise physiology, the movement sciences, and sport and exercise psychology), combined with a crucial eye on health policy, constitute our field. Although nothing can be substituted for experience, this text offers the background and introduction to the tools needed for the planning, implementation, and evaluation of physical activity promotion programs. This is the first textbook of its kind designed for a semester-long course in the field.

Few singular health behaviors can have as broad an impact on the health of individuals and populations as physical activity. The scientific base is growing and solidifying regarding the effects of physical activity on all-cause morbidity and mortality due to multiple noncommunicable diseases such as heart disease, some cancers, diabetes, and osteoporosis.

It is a very exciting time of growth in physical activity and public health. The seminal scientific works of Dr. Jeremy N. Morris and Dr.

Ralph S. Paffenbarger Jr. helped set the stage for what is now a worldwide focus on advancing the science, as well as reducing physical inactivity and promoting the benefits of regular physical activity for the prevention and treatment of chronic diseases and other health challenges. As the science and practice advance, physical activity is receiving increased attention from policy and organizational decision makers worldwide, including governmental ministers of health. Professional societies have been created to focus on advancing the research and practice of the field, the scientific literature has expanded dramatically on multiple fronts, and physical activity and inactivity are becoming parts of health policy decisions at all levels. An outstanding example is the Toronto Charter for Physical Activity: A Global Call to Action. This advocacy tool drives policies worldwide that are supportive of the role of physical activity in promoting health.

HOW THIS BOOK IS ORGANIZED Foundations of Physical Activity and Public Health is organized into three parts and 16 chapters.

PART I: INTRODUCTION TO PHYSICAL ACTIVITY AND PUBLIC HEALTH Part I introduces concepts of public health, kinesiology, and measurement. The chapters in this part highlight fundamentals of each and how they have come together.

Chapter 1 introduces the fundamentals of public health and provides information about the various subdisciplines of public health and how public health differs from medicine. Finally, there is a discussion about how public health policy is often linked to the legal and regulatory system, as well as discussion of an emerging specialization in public health.

The fundamentals of kinesiology are discussed in chapter 2. In the past, exercise was studied and often promoted as a means of enhancing maximal performance rather than promoting basic health

benefits for all. The components of exercise training are presented as well as the methods for applying them to target populations. The general health, fitness, and performance effects of physical activity and exercise are discussed. A final section presents ways to integrate traditional exercise prescription into physical activity and exercise programs.

Chapter 3 focuses on the emergence of the subdiscipline of physical activity and public health. Examples of the interdisciplinary interest in the field of physical activity and public health are reviewed and the knowledge, skills, and aptitudes for careers in physical activity and public health are provided.

In chapter 4, the importance of measuring physical activity is introduced, and the strengths and weaknesses of various laboratory and field methods are discussed. Overviews of the following techniques are included: indirect calorimetry, doubly labeled water, wearable devices, direct observation, and self-report instruments. Observational techniques such as physical activity surveillance and sources of data-based comparison are also discussed.

PART II: HEALTH EFFECTS OF EXERCISE AND PHYSICAL ACTIVITY The scientific base of the health effects of physical activity and inactivity is remarkable in its size and complexity. It continues to grow each year, and the overwhelming evidence for the health benefits and risks of physical activity provides much of the rationale for action.

Cardiovascular and metabolic diseases and their association to physical activity are presented in chapter 5. The chapter starts with a discussion of the prevalence and economic costs of cardiovascular and metabolic diseases. Specific physiological, biomechanical, and behavioral adaptations to physical activity and exercise are also identified. Common testing methodologies for predicting and diagnosing metabolic disease are provided. The evidence for the effect of physical activity on cardiorespiratory and metabolic disease is discussed.

Chapter 6 contains common definitions for overweight and obesity and a discussion about the prevalence (U.S. and worldwide) and the economic costs of these conditions. A discussion of caloric balance is included, and the contributions that physical activity and exercise have on balance-related issues are highlighted. The various risk factors associated with overweight and obesity are discussed, and specific physiological, biomechanical, and behavioral adaptations to physical activity and exercise are identified. Methods for assessing body composition are provided. The effects of physical activity on weight loss, weight maintenance, and weight regain are discussed along with the physical activity guidelines for achieving caloric balance and a healthy weight.

Chapter 7 focuses on musculoskeletal disorders and functional health. The risk factors, prevalence, and economic costs of musculoskeletal disorders and disability are discussed. Specific physiological, biomechanical, and behavioral adaptations to physical activity and exercise are provided. Common testing methodologies for muscle function and functional health are included. The evidence for the effect of physical activity on musculoskeletal disorders and disabilities in functional health is discussed.

In chapter 8, cancers related to physical inactivity are discussed and the prevalence of each is highlighted. The mechanism by which physical activity might reduce the risk of some cancers is included along with a discussion of common risks for cancer. Specific physiological, biomechanical, and behavioral adaptations to physical activity and exercise are identified. Included is a discussion of scientific evidence supporting the benefits of physical activity for cancer survivors, as well as evidence for the role of physical activity in the prevention of cancer.

Chapter 9 examines the effects of physical activity on brain health. The prevalence, economic costs, and risk factors of brain health disorders are discussed. A framework for studying brain health problems and their response to physical activity interventions is provided along with a discussion about the effects of physical activity

on brain function, which includes reaction time, learning tasks, cognitive function, and academic achievement. The recommendations for physical activity complete the chapter.

In chapter 10, adverse events associated with physical activity are discussed. Participation in regular physical activity and exercise may increase the risk of musculoskeletal injuries and sudden cardiac death in some cases. This chapter contains a discussion about defining adverse events, the prevalence of problems, the risks associated with injury, and the adaptive processes that may help prevent injury.

PART III: STRATEGIES FOR EFFECTIVE PHYSICAL ACTIVITY PROMOTION The chapters in part III introduce evidence-based strategies for increasing physical activity in individuals and populations. Public health is characterized by translating science into action to advance the health of the population. The strategies presented in part III have been scientifically demonstrated to increase physical activity and can be used for action in a variety of settings.

Methods for promoting physical activity are discussed in chapter 11, which opens with a discussion about the importance of using the Guide to Community Preventive Services as a resource for identifying physical activity intervention programs that work. A discussion about the impact of community-wide campaigns on increasing physical activity is included along with an overview of mass media campaigns.

In chapter 12, the rationale for school-based physical activity interventions is presented. The scientific benefits of physical activity in youth are reviewed, and commonly used physical fitness tests for school settings are discussed. A section that highlights current U.S. strategies and policies for promoting physical activity via school- based programs is included. The remainder of the chapter focuses on examples of evidence-based school physical activity programs.

In chapter 13, the focus is on evidence-based strategies for behavioral and social approaches to physical activity promotion. This chapter includes a discussion of current behavioral theories and theoretical models that are used to explain physical activity behavior in individuals. Social support strategies for physical activity promotion in communities are defined and highlighted, and examples of both types of approaches are provided.

In chapter 14, environmental and policy influences on physical activity are reviewed, as are strategies for change. The ways in which aspects of the physical and built environment can encourage or inhibit physical activity are reviewed. The role of urban design for physically active populations and evidence-based strategies for change are discussed.

In chapter 15, evaluation of physical activity programs is introduced. This chapter begins with a discussion of the six-step Physical Activity Evaluation Framework developed by the Centers for Disease Control and Prevention (CDC). The concepts of formative evaluation, process evaluation, outcome evaluation, and cost- effectiveness evaluation are covered. Logic models are presented. This chapter also contains discussions about evaluation designs, data collection and analysis, and publishing and communicating results.

Chapter 16 is the final chapter in the text; it focuses on building effective partnerships for physical activity programs. Examples of effective partnering include the U.S. National Physical Activity Plan, the World Health Organization Global Action Plan for Physical Activity, and the international Toronto Charter for Physical Activity. Strategies for physical activity advocacy are included, and models for advocacy and effective leadership conclude the chapter.

SPECIAL FEATURES The content organization of Foundations of Physical Activity and Public Health, Second Edition, is based on contemporary teaching

principles to maximize learning opportunities for students. Following are the features in each chapter:

Objectives: summaries of take-away messages you should learn by reading and studying the material Opening Questions: questions to help you think about how you can use information in the text Sidebars: examples of topics covered in the text, which will help you translate theory into practice Case Studies: real-life examples of selected concepts covered in the chapter Leader Profiles: mini-biographies of world leaders in physical activity and public health, all updated for the second edition; each leader addresses four key questions about his or her work in the field What You Need to Know: a bulleted review of the chapter to help you study the information provided Bibliography: additional published resources for further study

NOTE TO STUDENTS As the field of physical activity and public health expands, an increasing number of job opportunities will be available for those who achieve the core competencies as endorsed by the National Physical Activity Society, established in 2006 as the National Society of Physical Activity Practitioners in Public Health. Coursework that covers concepts of physical activity and public health will help future graduates in diverse employment settings such as public health and health care, business and industry, the nonprofit sector, education, mass media, urban planning and architecture, and parks and recreation. University students in majors and minors such as kinesiology, athletic training, physical therapy, medicine, nursing, and nutrition, as well as trainers in public services (fire, police, and military), rehabilitation specialists, and wellness instructors will find a natural connection between their professional duties and the need

for promotion of physical activity and public health to colleagues and communities. Core competency areas covered by the text are listed at the end of each chapter in the “Chapter Wrap-Up” section.

Additionally, a new web resource provides a variety of interactive activities, includeing e-Media links, flash card activities, and study questions to help you learn and understand the information presented in the text.

NOTE TO INSTRUCTORS This text is targeted for students in exercise science or public health programs who are enrolled in elective courses that expand their understanding beyond what is taught in traditional core courses. The 2018 Physical Activity Guidelines for Americans, the accompanying Physical Activity Guidelines Advisory Committee Report, and the CDC’s Guide to Community Preventive Services are valuable resources that provide much of the framework for the development of this text. You can find links to these in the web resource.

The following free ancillaries are also available to instructors who adopt this textbook:

The instructor guide includes syllabus suggestions, teaching tips, and sample class assignments. The test package has over 300 questions, including multiple- choice, true-false, short answer, and fill-in-the-blank questions. The test package can be downloaded in multiple formats, depending on your teaching needs, and can also be modified to include test questions that you create. The image bank includes figures and tables from the text. You can use these items to create your own PowerPoint presentations, handouts, or other class materials. A new presentation package offers PowerPoint slides for each chapter, outlining key points and including important figures from the text.

The web resource offers key term activities, e-Media links, and downloadable study questions for each chapter.

These resources can be accessed at www.HumanKinetics.com/FoundationsOfPhysicalActivityAndPublicH ealth. The authors, who have taught courses in physical activity and public health, have helped develop all of the ancillary materials.

We trust that Foundations of Physical Activity and Public Health, Second Edition, will allow you to develop courses that inspire students to pursue careers in physical activity and public health.

ACCESSING THE WEB RESOURCE

Throughout Foundations of Physical Activity and Public Health, Second Edition, you will notice references to a web resource. This online content is available to you for free upon purchase of a new print book or an ebook. All you need to do is register with the Human Kinetics website to access the online content. The following steps explain how to register.

The web resource offers learning activities that focus on key term comprehension, e–Media links, and downloadable study questions. We are certain you will enjoy this unique online learning experience.

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ACKNOWLEDGMENTS

I am grateful for the past, the present, and the future. Mentors in my past, especially Steven N. Blair believed in me and showed me the path. Colleagues in the present keep me stimulated and motivated. My students in the future will be leaders in physical activity and public health. This second edition would not have been possible without all of you. —HWK

Thanks to the leadership and staff at Human Kinetics for allowing us to complete this second edition. Thanks to Dr. Kohl for making this new edition a reality and to Dr. Salvo for joining our author team. Finally, thanks to my wife Mary for her love and support of all my writing efforts. —TDM

There are many people that have helped me become the scholar I am today. I thank each and every one of you for helping shape my career in public health. I would like to especially express my gratitude to Juan Rivera and Michael Pratt for your continuous guidance, support, and generosity.

I would also like to acknowledge that my professional achievements would not have been possible without the unconditional love and support of my family. I dedicate this book to my parents, Alfredo and Regina Salvo, for your patience and dedication. To Freddie, my accomplice and lifelong friend. To my husband, Umberto, thank you for always helping me see the glass

half full, and for being my partner and best friend. Arturo — también esto es para ti.

Last but certainly not least, I would like to express my immense gratitude to Bill and Tinker for inviting me to contribute to this work. Bill, thank you for believing in me and for your incredible support of my professional and personal growth. I am forever grateful for your mentorship and friendship. —DS

PART I Introduction to Physical Activity and Public Health

CHAPTER 1 Fundamentals of Public Health

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The definition and history of public health »  The five main pillars of public health and how public health

has become specialized »  The five main principles that guide health promotion and

health education efforts in public health »  The 10 essential functions that support the core services

of public health

»  Why public health policy is often linked to legal and regulatory systems

»  The emerging physical activity specialization in public health

OPENING QUESTIONS What comes to mind when you read the words public health?

»  Screening children for nutritional deficiencies? »  Immunization programs to prevent an outbreak of influenza? »  Disaster responses to prevent disease transmission during and

after a hurricane or earthquake?

»  Prenatal education for expectant mothers?

»  Promotion of physical activity to lower the burden of chronic, noncommunicable diseases such as heart disease and diabetes mellitus?

If you answered yes to any of these questions, you are correct. Public health is all this and more.

Public health is a field that encompasses many disciplines in an effort to promote and protect health and prevent disease and disability in defined populations and communities. Although medicine and medical training are integral to public health, particularly in understanding the mechanisms of disease transmission, medicine is more interested in the treatment of and cures for diseases and disabilities in individuals. The key difference between public health and medicine is that public health has traditionally focused less on individuals and treatment and more on populations and prevention.

Therefore, public health should focus on problems that affect, or could affect, a substantial portion of the population. For this reason, rare diseases and disabilities and seemingly random health events are often less of a concern to the public health field than problems

that may affect many people in a population. This is not to say that such situations are not important, particularly to the people afflicted, but rather, that the focus of public health is on the health of the population as a whole. Overall, the health of a population is rarely improved by focusing only on rare diseases and health problems that affect the few.

This first chapter offers an overview of the principles and key areas of public health and describes the fundamental services of public health. Happily, public health has grown far beyond its origins and has allowed populations to thrive in the face of new and emerging health problems.

DEFINING MOMENTS IN PUBLIC HEALTH Although a complete treatment of the history of public health is beyond the scope of this chapter (it could, and does, fill whole books), an understanding of some defining moments in public health is instructive. This understanding helps contextualize the emergence of physical activity and public health as a separate discipline within public health. Winkelstein (2011) offers a more complete treatment of the history and evolution of public health.

Although disease and epidemics have occurred for thousands of years, the earliest roots of organized public health emerged in the mid-14th century. At the time, the Black Death (bubonic plague) ravaged Europe, killing an estimated 25% of the population. As we know now, the disease was tied to the black rat, the rat flea (Xenopsylla cheopis) that lived on the blood of the black rat, and the bacterium Pasteurella pestis that helped the flea to seek out additional food by biting warm-blooded humans. At the time, however, an understanding of the germ theory of infection and disease (i.e., that microorganisms are responsible for sickness and not simply “bad air” or other nonbiological reasons) was still 400 to 500 years in the future. Advances in transportation (shipping) around Europe and the Middle East spread the disease to other geographic areas. Although no one knew when or how the disease would strike,

public health was advanced by the creation of health boards and systems for counting and collecting the dead. Unknowingly, this was the first attempt at a vital statistics system, which is now routine in public health organizations throughout the world.

Although the cause of the bubonic plague was unknown in its time, counting the dead was one of the first examples of creating public health statistics. Can you think of examples of tracking modern diseases to the source?

Another advance in public health grew out of concern about the health of workers (particularly children) and the deplorable working conditions that were rampant early in the industrial revolution of the 19th century. Little regulation was in place at the time, and workplaces were polluted, unsafe, and very conducive to disease and injury. Young children were working to support families, and the poor and less advantaged were particularly susceptible. The association between poverty and health was recognized early in the 19th century, and policies and programs to address such disparities began to emerge. Edwin Chadwick in Great Britain was an early leader in the cause of improving sanitation, housing conditions, worker safety, and garbage disposal practices in poor communities. This is one of the first examples of using policy and legislation to improve health.

The lens of history points to the early 20th century as another critical period in the history of public health. With the legitimization of the germ theory of disease transmission by Robert Koch and Louis Pasteur (working independently) in the late 1800s, new methods for treating (and preventing) disease emerged. Sanitation, quarantine, and other methods for controlling infectious diseases became standard practices in cities. Boards of health were developed to deal with health threats to the community. Vaccines and antibiotics were discovered and quickly resulted in monumental improvements in disease control.

The 20th century represents a bridge between a focus on infectious (communicable) diseases and a focus on chronic (noncommunicable) diseases. Once infectious diseases were becoming less influential, nutritional diseases (due largely to micronutrient deficiencies) became a priority. Maternal and child health was also a critical piece of the public health puzzle in the 20th century. The infant mortality rate, as well as the maternal mortality rate, was abominable. Mandating training and licensure of midwives were public health interventions that helped to control this burden.

Finally, following the decline of infectious diseases and nutritional deficiency diseases, the mid-to-late portion of the 20th century was witness to the emergence of chronic diseases (also known as noncommunicable diseases) as those that had the largest population reach and thus were a substantial public health concern. Heart disease, diabetes mellitus, cancers, mental health disorders, and musculoskeletal disorders firmly replaced infectious and nutritional diseases as key causes of death and illness in the world. To be specific, a 2018 report by the World Health Organization (WHO 2018) detailed that more than 60% of all deaths worldwide in 2016 were due to chronic diseases (see table 1.1).

Table 1.1   Ten Leading Causes of Death Worldwide in 2016 Cause Deaths in millions % of deaths

Ischemic heart disease 9.43 16.6

Stroke and other cerebrovascular diseases 5.78 10.2

Chronic obstructive pulmonary disease 3.04 5.3

Lower respiratory system infections 2.96 5.2

Alzheimer’s disease and other dementias 1.99 3.5

Trachea, bronchus, and lung cancers 1.71 3.0

Diabetes mellitus 1.60 2.8

Road traffic accidents 1.40 2.5

Diarrheal diseases 1.38 2.4

Tuberculosis 1.29 2.3

Reprinted by permission from World Health Organization. Global Status Report on NCDs. (Geneva, Switzerland: WHO). www.who.int/chp/ncd_global_status_report/en/index.html. Accessed 16 June 2011.

Only 150 years in the past, infectious diseases were the leading concern and the primary cause of sickness and death. Today, diseases influenced by lifestyle and genetics are the greatest public health concern. This remarkable transition in public health coincides with the beginning of the physical activity story.

AREAS OF SPECIALIZATION IN PUBLIC HEALTH An important part of the evolution and history of public health has been the emergence of training programs and techniques to address public health challenges. The establishment of the London School of Tropical Medicine and Hygiene in the United Kingdom, and of the Johns Hopkins School of Public Health in the United States, in the early 20th century were key steps to creating a workforce with the skills necessary for handling public health problems. Following these early efforts, additional training and certification of academic programs took hold very rapidly in the United States. In 2011, the United States, Canada, and Mexico had 66 accredited schools of public health providing leadership and training opportunities for master’s and doctoral students. These training programs have

evolved over the years, resulting in widely accepted standards for areas of training and specialization in public health.

Figure 1.1 illustrates the five broad areas of specialization, or pillars, of public health, each of which contributes uniquely to the field.

EPIDEMIOLOGY AND DISEASE CONTROL Epidemiology is the basic science of public health. The word epidemiology comes from Greek origins: epidemia (“on people”) and -ology (“to study”). Although several definitions exist, a modern-day definition of epidemiology is “the study of distributions and determinants of disease and disability in populations” (Mausner and Bahn 1974). Notable in this definition, and following from the preceding discussion, is the word populations. Epidemiologists are focused on a defined population and how a disease or disability affects that population. What causes the spread of the disease or disability? How can it be prevented? How many people are affected? What types of people or other organisms are possibly affected more than others? Who is at risk? How many could be affected in the future? These are all questions that epidemiologists are trained to answer.

Figure 1.1   Five pillars of public health.

Epidemiology is a quantitative scientific discipline that relies heavily on statistics and study design. With the transition in the 20th century to disease burden being attributed primarily to noncommunicable diseases, epidemiological methods have evolved to apply not only to infectious disease outbreak investigations, but also to studies of longer-term chronic disease investigations. For example, much of what we know about risk factors for heart disease (e.g., poor lipid and lipoprotein profile, high blood pressure, cigarette smoking, physical inactivity) came from early and ongoing epidemiological studies of (mostly) men with and without these characteristics. Researchers used epidemiological methods to compare and contrast study participants with and without the conditions, and then calculated the risk associated with the occurrence of a disease. These techniques have evolved as the need to address more complicated analytical questions has increased.

KNOWLEDGE INTO ACTION Public health science is characterized not just by the accumulation of new knowledge, but also by the application of that knowledge to improve health. Public health research must be able to be translated to action for disease prevention, health promotion, or both.

ENVIRONMENTAL HEALTH The environment can be defined as “all that is external to the host organism” (WHO 2011b)—including physical, biological, and cultural influences. Our physical environment (i.e., where we live, work, and play) has a powerful influence on our health. The air we breathe, the water we drink, the food we eat, the safety of our work environment, our exposure to radiation, and the ways we control these environmental influences can promote or hinder public health. Thus, a large part of public health addresses environmental health.

Major advances have been made in public health as a result of environmental health studies. Prohibition of lead-based paint to reduce the risk of learning disabilities in children, fluoridation of water supplies to reduce dental problems in communities, air quality regulations for automobile manufacturers and industrial polluters to promote cleaner air and water, and food safety standards to reduce the risk of food-borne diseases are all examples of public health initiatives that came about as a result of environmental health studies. Can you think of others?

Clearly, environmental influences on health have been known for centuries. Systematic approaches to studying environmental influences on health, quantifying these influences, and prioritizing resources and approaches to eliminate health hazards have been advanced only relatively recently. We will learn in chapter 14 that our understanding of the role of the environment in promoting or inhibiting physical activity has advanced rapidly since the mid-1990s.

We can now identify barriers and correlates in the physical, social, and cultural environments that influence physical activity participation. This has been, and will continue to be, a major growth area in the field of physical activity and public health.

The construction of bike- and pedestrian-friendly routes increases access to places to be active in a community. In addition to physical activity, what are other benefits of such efforts?

HEALTH PROMOTION AND HEALTH EDUCATION Why do some people exercise consistently, avoid tobacco, eat well, use alcohol responsibly, avoid illicit drugs, see their doctors regularly, and do other things necessary for health maintenance, whereas others do not? How can we best teach basic health concepts for lasting effectiveness? What is the most effective education strategy to improve birth outcomes for teenage mothers? How can population-level health behaviors be changed to maximize life expectancy and quality of life? Questions such as these are routinely addressed in the health promotion and health education pillar of public health. Although the environment and our genetic makeup contribute substantially to our health status, how we deal with health

threats through our behavior has become a major focus of public health.

Much of the basis for health promotion and health education in public health comes from the concept of social justice, which is central to many ideas of public health. Social justice in public health refers to the assumption (some call it an imperative) that the health burdens and benefits in a population should be distributed equitably. We have known for centuries that poverty is a predictor of disease, disability, and poor quality of life. Those who promote health promotion and health education strategies in public health aim to be part of a solution to reduce such disparities.

The WHO has advanced five principles to guide health promotion and health education efforts in public health (WHO 2011b). See the highlight box WHO Principles of Health Promotion for a description of these principles.

WHO PRINCIPLES OF HEALTH PROMOTION Empowerment and Inclusion Health promotion should empower all individuals and communities to take some responsibility for the influences on their personal health.

Intersectoral Collaboration Health promotion programs should be directed at all the relevant determinants or causes of health and should therefore include relevant collaborations among agencies and sectors with influence beyond the health or medical care sector.

Multidimensional Health promotion initiatives should use all tools possible to minimize health hazards and promote positive health. These dimensions include, but are not limited to, communication, legislation or policy, education, community or organizational change, and finance.

Participatory

Health promotion programs should strive to be inclusive at all steps and seek to maximize participation individually and collectively.

Advocacy All people with an interest in health, including medical care systems, should take responsibility for health promotion and health education.

Based on WHO 2011b.

HEALTH ADMINISTRATION AND POLICY Health administration and policy is the fourth pillar of public health and focuses on the delivery of public health services. This area of expertise addresses important skills such as budgeting, policy development and analysis, planning and prioritization, and communication. In keeping with the theme that public health is action oriented, health administration and policy skills support the appropriate implementation of programs that, theoretically, are derived from research in the area. A good example lies in the HIV/AIDS epidemic. Research has shown that needle exchange programs likely reduce hypodermic needle sharing among intravenous drug users and thus decrease the risk of transmission of HIV/AIDS (Palmateer et al. 2010). Health administration and policy experts can use such data and the results of studies to plan community-based projects that promote such programs.

In the field of physical activity and public health, the effects of policies and program administration are an emerging knowledge base. As addressed in part III of this textbook, policies for providing places to be physically active are showing promising results for the promotion of physical activity. Expertise in health administration and policy is critical for the implementation and evaluation of such efforts.

BIOSTATISTICS AND DATA SCIENCE Public health relies on both qualitative and quantitative methods to move from knowledge to action. Biostatistics provides the basis for

the quantitative branch. Is the difference between two interventions to promote breast cancer screening in a community due to the effect of the intervention, or simply due to chance? What is the predicted number of cases of influenza in the upcoming year? Using statistical approaches, can future health care costs be accurately predicted for children born this year? Based in mathematical theory, biostatistics allows for the practical and rational analysis of data, the interpretation of study results, and the translation of those results into action. Biostatisticians and epidemiologists work closely to advance the science of public health.

CORE FUNCTIONS OF PUBLIC HEALTH Even with the specializations in public health listed earlier, the core functions of public health professionals and agencies must be defined. What should these professionals and agencies do? How does a public health agency interact with the medical care system to promote and protect the health of communities? Do standards for public health practice exist? In 1999, a joint project led by the U.S. Office of Disease Prevention and Health Promotion (ODPHP 2011) was created to describe and define the fundamental services of public health. The Public Health Functions Project used this opportunity to strengthen the public health infrastructure in the United States by developing and describing a common set of primary services that define public health. By addressing these functions, in combination with skill sets learned in the topic areas of the five pillars of public health, professionals can effectively promote public health. The 10 essential functions of public health are listed in figure 1.2.

The 10 essential functions of public health help define and guide the core services of public health. Competencies in the functions are developed through training in and across the five pillars. Actually, these functions go beyond a simple listing—they have been adopted as the key organizing framework for the CDC’s National Public Health Performance Standards Program (NPHPSP 2011). The purpose of the NPHPSP is to improve the quality of public health

practice and the performance of public health systems by providing performance standards, engaging and leveraging partnerships, promoting continuous quality improvement, and strengthening the science base for public health practice improvement.

These 10 essential functions are meant to interact in a cycle (see figure 1.2) to maximize public health. The assessment phase begins the cycle with the monitoring of health and the diagnosis and investigation of important or emerging health problems. Policy and development ensues, including informing, educating, and empowering people regarding health threats, mobilizing partnerships to deal with those health threats, and developing policies to minimize threats and promote health. During the assurance phase, laws and regulations are created and enforced, linkages to care are created, a competent workforce is developed, and effectiveness is evaluated. The cycle can then begin anew with ongoing monitoring. Importantly, this cycle revolves around research advances and administration (management) skills. Can you think of a specific public health problem and apply steps to each of the 10 essential functions?

As addressed in this text, physical inactivity is a public health problem that can be viewed as a content area addressed in terms of these essential functions. Each function can and should support physical activity promotion. Public health professionals with interest and expertise in physical activity can make this happen.

LEADER PROFILE Ross Brownson, PhD

Why and how did you get into the field of Physical Activity and Public Health? I have intersecting personal and professional interests in physical activity and public health. Physical activity has always been an important part of my life. I grew up in western Colorado, and I was always active in sports, hunting, and fishing. My days in competitive athletics are over but I am still physically active every day. In my professional life, one of our first grants that was funded by the CDC was a cardiovascular disease intervention project in the southeastern “bootheel” region of Missouri. This project initiated a series of interventions to promote physical activity in rural communities by building and promoting the use of walking trails.

Did any one person have a major influence on your career? How? I have been lucky to have had many great mentors in my career. One person who stands out is John Bagby; he was the department chair and part of my dissertation committee during graduate school. He later hired me for my first job in public health practice during his time as a division director with the Missouri Department of Health. John had been deputy director of the CDC and led the campaign to eradicate malaria. His vast knowledge of public health practice, and his energy, integrity, and positive outlook have guided me since we first met in 1980.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice?

I am particularly interested in promotion of physical activity in disadvantaged populations—this includes rural communities, racial and ethnic minority populations, and low- and middle-income countries. Much of my current research focuses on implementation science, which seeks to bridge the gap between what we know will improve health (effective interventions) and application—the implementation and continuation of evidence-based programs and policies. The first study on physical activity and health was published in 1953, yet it was not until decades later that we developed evidence-informed policies and programs to address physical activity. Much of this research focuses on accelerating the uptake of evidence- based interventions in state and local public health agencies. I am also focused on training and mentoring the next generation of researchers and practitioners. For those of us in the later stages of our careers, this is a crucial area on which to concentrate.

Why do you do what you do? I often say that being a college professor is the best job in the world because you get to choose the topics to research and courses to teach and you’re always learning. Having worked in a state health department and in the university setting, I find it fulfilling to bridge the science of physical activity promotion with practical applications of research. It is exciting to see the lasting impacts of our projects (e.g., walking trails) that are now a part of many communities.

What are two key issues that must be addressed by 2030? We have written about macro-level forces of change affecting public health (Erwin and Brownson 2017). Among these forces are climate change and rapid demographic transitions (i.e., the aging of the U.S. population and the increasing proportion of racial and ethnic minority populations). The intersection of physical activity research and practice with these forces of change is crucial for our future ability to understand and promote physical activity. Another related area of focus for the future is workforce development in public health practice. The retirement of baby boomers provides new opportunities and challenges. We need to fill jobs in public health practice with skilled professionals who are equipped with

more traditional skills (e.g., epidemiology, evaluation) but also new capabilities (e.g., systems thinking, communication, policy analysis) that are sometimes lacking.

Figure 1.2   Cycle of the 10 essential functions of public health.

PUBLIC HEALTH LAW Although efforts have been made to promote health and behavior change among individuals in a population, many times the best strategy for making meaningful changes in public health is through the legal system, regulatory system, or both. Indeed, many of our most important public health successes have come from such changes: immunization laws for school children to prevent the transmission of infectious diseases at school, legislation and regulations to prohibit cigarette use in public places to reduce

exposure to secondhand smoke, motorcycle helmet laws to reduce traumatic brain injury and death among riders involved in accidents, minimal workplace safety standards and inspections to reduce the risk of occupational injuries, and food safety and transportation standards to reduce the risk of food-borne illnesses. These advances in public health did not rely on individual or community- generated changes, but instead on legal or regulatory action.

Such legal avenues have given rise to an entire area of specialization called public health law. Specialists in this field seek to leverage legal and governmental authority to promote and protect the health of populations. Experts in public health law, particularly as it relates to issues of preparedness with the emergence of bioterrorism threats (e.g., anthrax), mass disasters such as earthquakes and hurricanes, and possible disease pandemics such as avian influenza, have developed strategies and approaches as well as research agendas to move the field forward toward optimal health protection. They constantly deal with the issue of balancing individual rights with the moral obligation to minimize risks in a population.

FUTURE OF PUBLIC HEALTH Public health is a vast discipline encompassing many specialties and functions. At the core, public health seeks to promote and protect the health of populations. With health threats continuing to emerge as developed countries face new challenges and developing countries face the challenges of modernization, public health should be used to predict these threats and respond accordingly. Physical activity and public health is a new subdiscipline in this area that bridges the traditional areas of public health and kinesiology. Large, unexplored areas need to be addressed in physical activity and public health, many of which will be introduced throughout this textbook.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Public health is a field that encompasses many disciplines in an effort to promote and protect health and prevent disease and disability in defined populations and communities. The key difference between public health and medicine is that public health has traditionally focused less on individuals and treatment and more on populations and prevention. Public health encompasses health strategies that can be implemented collectively but are impossible or impractical to apply individually. Chronic (noncommunicable) diseases have replaced infectious diseases as leading causes of death in the world. Epidemiology is the basic science of public health. The five pillars of public health are epidemiology and disease control, environmental health, health promotion and health education, health administration and policy, and biostatistics and data science. There are ten essential functions of public health that help define and guide the core services of the field. Competencies in the functions are developed through training in and across the five pillars.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the

text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Erwin PC, Brownson RC. 2017. Macro trends and the future of

public health practice. Annual Review of Public Health 38: 393- 412.

Mausner J, Bahn AK. 1974. Epidemiology: An Introductory Text. Philadelphia: Saunders.

Palmateer N, Kimber J, Hickman M, Hutchinson S, Rhodes T, Goldberg D. 2010. Evidence for the effectiveness of sterile injecting equipment provision in preventing hepatitis C and human immunodeficiency virus transmission among injecting drug users: A review of reviews. Addiction 105: 844-859.

U.S. Centers for Disease Control and Prevention. 2011. National Public Health Performance Standards Program. www.cdc.gov/nphpsp/index.html. Accessed 17 June 2011.

U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. 2011. Public Health Functions Project. www.health.gov/phfunctions/Default.htm. Accessed 16 June 2011.

Winkelstein W. 2011. History of Public Health. www.enotes.com/public-health-encyclopedia/history-public- health. Accessed 16 June 2011.

World Health Organization. 2011b. Milestones in Health Promotion: Statements From Global Conferences. www.who.int/healthpromotion/milestones/en/index.html. Accessed 16 June 2011.

World Health Organization. 2016. Global Status Report on NCDs. www.who.int/chp/ncd_global_status_report/en/index.html. Accessed 16 May 2019.

World Health Organization. 2018. The top 10 causes of death. https://www.who.int/news-room/fact-sheets/detail/the-top-10- causes-of-death?f5tp=1. Accessed July 2019.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.4.1, 1.4.2, 1.4.3, 2.1.1, 2.2.1, 2.4.1, 2.4.6, 3.3.1, 3.3.2, 3.4.2, 3.4.3, 4.3.3, 5.1.1

CHAPTER 2 Fundamentals of Kinesiology

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The field of kinesiology and how its subdisciplines have contributed to our understanding of exercise, physical fitness, maximizing performance, and the shifting paradigm of the promotion of public health benefits through physical activity

»  The concept of sedentary behavior and the importance of encouraging individuals and populations to adopt physically active lifestyles that meet or exceed minimal recommended national standards for health

»  The concepts and principles of exercise training »  The general health, physical fitness, and performance

effects of physical activity and exercise »  How to integrate the principles of traditional exercise

prescription programming for individuals—principles that focus on improved health outcomes while considering factors like age and mental and physical health—into physical activity and exercise plans for populations

OPENING QUESTIONS »  Do you know the areas of kinesiology that positively affect

individual health, physical fitness, and peak performance through the traditional exercise training model?

»  How can knowledge of the fundamentals of kinesiology and exercise training help you promote health and physical fitness for populations in a public health model?

Chapter 2 introduces the field of kinesiology and the basic concepts of exercise training that have been used since the 1960s and 1970s to improve individual human performance and physical fitness (otherwise known as the traditional training model). You will learn how the traditional model of exercise training, based on the science of kinesiology, has evolved to include the promotion of public health. The emerging concept of promoting public health by increasing physical activity through the use of physical activity plans for populations is introduced at the end of the chapter and described in more detail in chapter 3.

Before we begin our discussion of kinesiology, it would be helpful to define some of the terms we will be using. Sedentary behavior is any waking behavior characterized by an energy expenditure of ≤1.5 METs (1 MET is equal to resting energy expenditure; see the Volume and Dose Response section for more information) while sitting, reclining, or lying. The majority of office work, driving a car, and sitting while watching television are examples of sedentary behaviors. Sedentary behavior and sedentary activity are similar but not synonymous; both are limited to energy expenditures ≤1.5 METs, but sedentary activity includes standing. Specifically, sedentary activity is activity requiring 1.0 to 1.5 METs, such as sitting and reading, watching television, or standing quietly.

Physical activity is any bodily movement that recruits skeletal muscles and results in energy (i.e., calorie) expenditure (Caspersen et al. 1985). Moving your arm up and down at your desk, skateboarding, lifting sacks of groceries out of the trunk of your car, and running a marathon are all types of physical activity. Exercise is a specific type of physical activity that is planned, repetitive, and done for a specific purpose (e.g., to improve health or physical function, physical fitness, or peak performance) (Caspersen et al. 1985). Walking the dog for 2 miles (3.2 km) every night, training for a soccer tryout, swimming laps, and working out at a gym are all examples of exercise. Athletes who train to improve components of their physical fitness are doing exercise. Anyone who gets out of bed in the morning is doing some kind of physical activity.

In contrast to physical activity and exercise, physical fitness is a set of measurable physiological parameters (like cardiorespiratory endurance [aerobic power], skeletal muscle endurance, skeletal muscle strength, skeletal muscle power, flexibility, balance, speed of movement, reaction time, and body composition) (Caspersen et al. 1985). Most people have their own views of what physical fitness looks like. What’s yours? An Olympic-caliber weightlifter? A marathon runner? The fastest kid on the basketball court? How

about your grandparents who are happy and able to physically do everything they want to do without limitations?

Figure 2.1 shows how physical activity can be promoted for individuals or populations based on specific goals like avoiding sedentary behavior, improving health and physical function, and improving physical fitness or peak performance. The physical activity and exercise continuum is included in the figure as an emerging concept that shows one should become physically active while avoiding sedentary behaviors and seeking to achieve specific health, physical fitness, and peak performance based on individual or population goals (Murray et al. 2019). It is important to understand how to develop individual- and population-based physical activity programs and to educate others about how to avoid regressing to long-term sedentary behaviors.

The following sections of chapter 2 and chapters in part II of the text provide details about how to develop and implement physical activity and exercise programming to achieve important physical fitness outcomes that focus on improved health and consider factors like age, and mental and physical health. You will also learn about key training components (frequency, intensity, time, and type [FITT]) and key training principles like overload, specificity, and progression and adaptation to help individuals with effective physical activity and exercise programming.

Figure 2.1   Integration of specific needs, goals, and outcomes with physical activity Based on concepts from USDHHS, PAGAC (2018).

Fitness can be measured or estimated in the very tightly controlled setting of a laboratory or in field settings in which groups of people can be tested simultaneously. Many useful techniques have been developed over the years to measure physical fitness very precisely. Although a full treatment of approaches to measure physical fitness is beyond the scope of this text, it is important to know that physical fitness, particularly aerobic fitness and muscular endurance, is frequently used to validate (or compare) measures of physical activity and exercise (see chapter 4 for more information).

The exercise sciences provide the basis for the academic discipline of kinesiology, which addresses the interrelationship of physiological processes and the anatomy of the body with respect to movement. The study of kinesiology includes the major exercise sciences of exercise physiology, the movement sciences, and sport and exercise psychology, which have been used for the past 30 years to promote the traditional exercise training model. Some of the other important exercise science areas of kinesiology you may have read about are physical education, health education, anatomy, pedagogy, motor learning, motor control, biomechanics, nutrition,

sociology of sport, sport management, athletic training, physical therapy, and special populations.

Figure 2.2 shows how the traditional exercise training model has been applied using the integration of major exercise sciences to maximize performance. When concepts from these same exercise sciences are integrated with physical activity, they can also be used to address public health policy goals.

The material presented in this chapter, when combined with the public health concepts discussed in chapter 1, represents a paradigm shift from primarily promoting exercise training and maximal performance (the 1970s and 1980s model) toward promoting physical activity for positive health outcomes (present-day model) as well. The integration of kinesiology concepts with public health outcomes is derived primarily from the two editions of Physical Activity Guidelines for Americans (USDHHS 2008, 2018) and the two editions of Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018) and is covered in more detail in part II of the text.

Figure 2.2   The traditional kinesiology-based exercise training model, which promotes the development of high levels of physical fitness, maximal performance, or both. Exercise physiology, the movement sciences (e.g., motor learning, motor control, motor development, motor behavior, and biomechanics), and sport and exercise psychology have been the primary integrators (connectors) used by professionals to develop training programs that yield positive outcomes.

KINESIOLOGY SUBDISCIPLINES AND EXERCISE TRAINING A complete review of the subdisciplines related to the field of kinesiology is beyond the scope of this text. What follows is an overview that focuses on the areas of exercise physiology, the movement sciences, and sport and exercise psychology. These primary exercise sciences were chosen because they have been the common integrators for both traditional exercise training models and emerging public health physical activity models (see chapter 3 and part II of the text for more).

Other important subdisciplines of kinesiology, such as nutrition and the sociology of sport (particularly as related to behavioral science), should also contribute to the development of physical activity and exercise public health plans, but they are not a primary focus of this text. Nutrition public health goals and interventions have been covered extensively in other resources, such as the 2015-2020 Dietary Guidelines for Americans, and you should become familiar

with these sources of information if you are not already. Behavioral and social methods for promoting physical activity and exercise are covered in more detail in chapter 13.

How many calories would you expend playing golf for 18 holes and carrying your clubs the whole round?

EXERCISE PHYSIOLOGY According to Kenney, Wilmore, and Costill (2019), exercise physiology is the study of how body structures and functions are altered by acute bouts of exercise or physical activity, and how the body adapts to the chronic stress of physical training. Exercise physiology also addresses the integration and coordination of body systems needed to maintain homeostasis, including the musculoskeletal, nervous, circulatory, respiratory, immune, endocrine (hormone-producing), digestive, urinary, integumentary (skin), and reproductive systems. The findings from exercise physiology training studies conducted since the 1960s were initially used for the prevention and treatment of chronic diseases such as cardiovascular disease. Exercise physiology has now become a key discipline that helps explain the role of physical activity and exercise in disease prevention and rehabilitation (see figure 2.3).

The study of exercise physiology evolved from a basic concept (i.e., exercise is medicine) promoted by the ancient Greeks and Romans such as Hippocrates and Galen and other physicians and scientists through time. Eventually, it developed into a complex discipline. Exercise physiology now addresses a spectrum of issues ranging from the molecular mechanisms associated with positive physiological adaptations via physical activity and exercise all the way to developing and promoting public health policies that drive the concepts presented in this text. The study of exercise physiology can be applied to a variety of physical activity and exercise settings and research questions, including the following:

What type of exercise training program can increase maximal oxygen uptake (fitness) ( O2max) the most? How much exercise is needed for optimizing the benefits of training while minimizing the risk of injury? How much physical activity per week is required for good health? How much physical activity or exercise is enough to maintain a healthy weight?

Figure 2.3   Role of physical activity and exercise in chronic disease prevention and rehabilitation. Reprinted by permission A.L. Gibson, D.R. Wagner, and V.H. Heyward, Advanced Fitness Assessment and Exercise Prescription, 8th ed. (Champaign, IL: Human Kinetics, 2019), 3.

MOVEMENT SCIENCES The movement sciences include the study areas of motor learning, motor control, and biomechanics. Motor learning is the study of how we learn and perform motor skills such as cycling and dancing. It also addresses the concepts that influence motor skills negatively or positively. Motor control is the study of human information processing and the integration of motor movements that involve motor planning and execution. Motor development is the study of changes in motor behavior in a lifespan. The term motor behavior collectively includes the study areas of motor learning, motor control, and motor development. Biomechanics is the study of physics applied to the understanding of movement in living organisms.

Movement scientists often study movement efficiency by observing movement patterns (through high-speed filming), measuring forces involved with movement, and developing equipment to maximize performance or protect participants from injury due to excessive movement forces. They also study the impact of instructional information and feedback on skill development.

Information from the movement sciences can be applied to a variety of physical activity and exercise settings and research questions, including the following:

How can we improve the efficiency or economy (i.e., reduce the energy cost) of walking in individuals? How do fundamental motor skills affect physical activity behavior and the development of physical fitness? What movement challenges are related to falls, and can physical activity and exercise prevent falls? How does aging affect the biomechanics of walking and energy expenditure?

The basic concepts of the movement sciences can help us understand factors such as the economy of physical movements, balance, and overall physical mobility. This understanding can help in the planning of physical activity and exercise interventions for populations.

HEALTH AND FITNESS PROFESSIONS In addition to the scholarly fields of kinesiology, other professional subdisciplines have started to embrace the promotion of physical activity as a primary mission related to their public health educational and rehabilitative initiatives. Fields such as health education, physical education, athletic training, physical therapy, and sport management all contain information that can, and should, be applied to physical activity and exercise public health interventions. In fact, the integration of the concepts from the subdisciplines of kinesiology have led to employment opportunities via the National Physical Activity Society (NPAS) and its certification opportunities (see chapter 3 for more). The NPAS was originally known as the National Society of Physical Activity Practitioners in Public Health (NSPAPPH) when it was established in 2006. The ability to translate research into effective clinical applications has become a

new requirement for many new job opportunities related to the promotion of physical activity and public health. Specific competency areas set by the NPAS can be found at the end of each chapter in the text.

SPORT AND EXERCISE PSYCHOLOGY Sport and exercise psychology is the study of behaviors and outcomes related to participation in sports or programs of exercise training. In sports, coaches are interested in sport psychology for a variety of reasons, including a desire to motivate their athletes to optimize performance. Behavioral cues can help athletes focus on key movement components to optimize their performance, and they can learn how to use specific cues to mentally rehearse how to react positively.

Currently, researchers in physical activity and public health often apply behavioral models such as the transtheoretical model of behavioral change and the social cognitive model (see chapter 13) to understand and promote positive health behaviors in individuals. The study of sport or behavioral psychology can be applied to a variety of physical activity and exercise settings and research questions, including the following:

What factors contribute to competition anxiety? What motivates people to become physically active? What motivates people to remain physically active for a lifetime? How does aging affect the motivation to participate in physical activity or exercise? How can we understand a population’s attitude toward and motivation to participate in physical activity?

Understanding several sport and exercise psychology theories or strategies is important for promoting behavioral change that can result in the achievement of public health, physical activity, and exercise goals. In fact, the traditional foundations of sport and

exercise psychology have become part of what we will refer to as the behavioral sciences for the remainder of the book.

Although the integration of the principles of kinesiology (particularly exercise physiology, the movement sciences, and the behavioral sciences) have been used extensively in individual exercise training programs for maximal performance, they are also essential for effective physical activity and exercise promotion and planning for populations. As you will learn in chapter 3 and part II of the text, kinesiology principles can be used to promote physical activity and exercise in the following lifestyle domains for populations: instrumental activities of daily living, household, leisure- time, occupational, and transportation (USDHHS, PAGAC 2018).

PRINCIPLES OF EXERCISE TRAINING, PRESCRIPTION, AND PLANNING Numerous principles of exercise training theory established in kinesiology literature are associated with the outcomes of optimizing performance and improving physical fitness. Exercise training theory has provided the basis for individual exercise prescription since the late 1970s. Therefore, an understanding of exercise training theory is needed for developing physical activity and personalized exercise plans. Participation in regular physical activity and exercise programs is essential for attaining basic functional health or physical function (USDHHS, PAGAC 2018) both individually and in populations (this is covered in detail in chapter 7). A functionally healthy person has been defined as “a reasonably (not perfectly) healthy person [with] a lot of health but some disability” (USDHHS 2008, p. G6-1) and includes the maintenance of functional ability and role ability. Measures of physical function include assessments of the ability to walk (e.g., usually gait speed), run, climb stairs, carry groceries, sweep the floor, stand up, and bathe (USDHHS 2018).

The following sections highlight general physical training principles and will help you integrate exercise science into long-term physical activity and exercise plans.

TRAINING THEORY AND PRINCIPLES Exercise training theory includes understanding how to use information from the exercise sciences (data-based outcomes from the research literature) and how to apply it effectively (the clinical practice of using training principles based on knowledge and experiences) to improve performance.

The science of exercise prescription is often based on the FITT concept; FITT stands for the frequency, intensity, time (duration), and type (mode) of exercise. The FITT concept can be further described as follows:

Frequency: How often an exercise or physical activity is performed. Frequency can be expressed in sessions, episodes, or bouts per week. Intensity: How hard one works, or the physical effort required to perform a physical activity or exercise. Intensity can be provided in absolute or relative terms such as low, moderate, or vigorous (see the discussion of intensity later in this chapter). Time: The amount of time in which a physical activity or exercise is performed. Duration is usually expressed in minutes. Type: The specific mode of physical activity or exercise.

A variety of factors or principles of training should be considered in order to realize adaptations. Traditional concepts of training theory were originally applied to individuals but are also pertinent to physical activity or exercise interventions for populations. Following are descriptions of the principles of training (labels and descriptions may vary by reference sources you use):

Practical goal setting: Determining the needs and goals of an individual or population. Genetics and individual variation: The genetics and potential for change of an individual or population with training.

Motivation: Evaluation of the drive or personal motivation of an individual or population and the need to provide appropriate feedback and reinforcement for success with physical activity programming. Teaching model: The need to teach individuals or populations how to participate effectively in physical activity or exercise to improve performance while reducing the risk of injuries. Fitness evaluation: Evaluating physical abilities to participate effectively in physical activity and exercise based on issues such as age, health status, and experience. Overload: Changing the FITT variables of a plan to improve physiological, movement, and psychological adaptations. Specificity: The specific physiological, movement, and psychological adaptations that occur as a result of the specific demands applied. Modifications: Adjusting the physical activity or exercise regimen based on factors such as disease, injury, and change in medications. Progression/Adaptation: An overall physical training plan that includes cycles of varying training volumes based on seasonal variations that provide appropriate rest and recovery periods. Overtraining: Participating in too much physical activity or exercise, which can result in negative physical performance; if continued, overtraining can produce negative psychological effects and increase the risk of musculoskeletal injury. Detraining: Discontinuing physical activity or exercise, and the rate and magnitude at which training benefits are lost. Recovery: How a person recovers from participating in a program of physical activity or exercise and the strategies that might help improve recovery time. Compliance: Why or how an individual or population continues to participate in or drops out of a physical activity or exercise program.

VOLUME AND DOSE RESPONSE The concept of total caloric expenditure is directly related to the volume, or dose, of training (physical activity or exercise) that accumulates over time. Daily voluntary caloric expenditure can account for 15 to 30% of a person’s total caloric expenditure. Many of the benefits of physical activity and exercise training are related to the amount of caloric expenditure achieved, which is why it should be considered when developing exercise prescriptions and public health, physical activity, or exercise plans. (Energy, or caloric, balance is described in detail in chapter 6.)

Essentially, when you are physically active, you expend more kilocalories (or kcals) than when you are sedentary. For example, an average person (approximately 70 kg, or 154 lb) expends about 1.2 kcals per minute while sitting at rest. Another common metabolic measure is the metabolic equivalent, or MET; 1 MET (3.5 ml . kg–1 . min–1) is equal to the resting energy expenditure for the same average person. It is also important to understand the difference between gross and net energy expenditure, because both are used by practitioners to measure or estimate total caloric expenditure. Gross energy expenditure (e.g., in METs) combines physical activity or exercise energy requirements with resting energy expenditure, whereas net energy expenditure reflects just the physical activity or exercise energy requirement.

INTEGRATING THE TRADITIONAL EXERCISE SCIENCE PRESCRIPTION INTO PERSONALIZED AND POPULATION EXERCISE PLANS Professional organizations and associations such as the American College of Sports Medicine (ACSM) have been promoting traditional exercise science methods for developing individualized exercise prescriptions since the 1970s. Although these traditional exercise prescription methodologies can be useful for promoting physical

activity and exercise to the public, many people may find them too complex and difficult to comply with. This may be especially true for people and groups who are interested only in improving or maintaining their health and fitness,

and not in performance outcomes. The Physical Activity Guidelines for Americans (USDHHS 2008, 2018) were developed with real-life examples of children, adolescents, adults, and older adults who have become and remained physically active.

Given the large prevalence of inactive people worldwide, it is important to become familiar with the

cases presented in the Physical Activity Guidelines for Americans (e.g., Harold, Maria, Douglas, Jake, Ebony, and Rumi). Understanding the individual and population strategies for the cases described in that report and learning how to integrate the physical training concepts presented in this chapter will help optimize success in physical activity promotion.

Figure 2.4   Physical activity, exercise, and health outcomes.

The volume, or dose, is the amount of physical activity or exercise performed and is based on frequency, duration, and intensity. Accumulation refers to acquiring a specific dose of physical activity or exercise, or achieving a physical activity or exercise goal, by combining several shorter bouts (e.g., three bouts lasting 10 minutes each to achieve 30 minutes of daily physical activity or exercise).

Dose-response refers to the amount of physical activity or exercise needed for achieving health, fitness, or performance goals. Dose-responses can be measured in terms of the frequency, duration, and intensity of physical activity or exercise or the total volume of work. Dose-responses related to physical activity or exercise are similar to those related to medications, in that responses vary with the dose of medication. Figure 2.4 shows some of the dose-response curves for physical activity or exercise in relationship to various health outcomes.

TYPE When considering the FITT variables for exercise prescriptions or physical activity and exercise plans, most exercise professionals recommend selecting the type of physical activity or exercise first, based on a practical goal-setting process for either individuals or populations.

The type (or mode) of physical activity or exercise can be categorized as anaerobic, aerobic, or combined, and as either static or dynamic. According to the Physical Activity Guidelines for Americans (USDHHS 2008, 2018), anaerobic activities require the use of nonoxidative energy systems (energy-producing reactions in the body that do not require oxygen) and engaging in these activities can improve the capacity of these systems and increase the tolerance of acid–base imbalance during high-intensity exercise, which allows one to work more effectively at high intensities for short durations. Examples of anaerobic activities that are also bone- strengthening activities are 100-meter sprints, gymnastics, and resistance training (e.g., weight training to increase mass and improve strength, power, and endurance). Aerobic activities require the use of large oxidative systems (i.e., heart and lungs) and improve cardiorespiratory endurance. Examples of aerobic activities are walking, cycling for 30 minutes, jogging, and rowing.

Combined physical movements take place in sports such as soccer, tennis, and racquetball that require significant contributions

of energy from both anaerobic and aerobic energy sources. Some examples of combined physical movements are the bouts of physical activity or exercise that involve high intensity interval training (HIIT), which requires working at a higher intensity for a few seconds or minutes followed by working at lower (recovery) intensities for the same amount of time. Interval training can be used for either improving health or maximizing performance.

Static physical activity or exercise (or isometric physical activity or exercise) is anaerobic and requires an increase in force production with limited range of motion (ROM); a test of handgrip strength is an example. Dynamic physical activity or exercise requires muscle-shortening (concentric) and muscle-lengthening movements (eccentric). Dynamic physical activities involve greater ROM than static activities and are usually rhythmic and more continuous. Regular engagement in static and dynamic physical activities is associated with higher flexibility and balance outcomes.

Physical activity and exercise can be further categorized as creating specific physiological demands for energy based on intensity and duration. Anaerobic power (or peak power) activities involve short-burst, high-intensity movements that last less than 15 seconds and stress the anaerobic energy pathways of the body. Anaerobic power abilities are highly related to genetics and the number of fast-twitch muscle fibers a person can recruit. Fast-twitch fibers are recruited primarily with higher work intensities and quickly fatigue, while slow-twitch fibers are primarily recruited at low to moderate work intensities and are fatigue resistant. Anaerobic capacity (also known as mean anaerobic power or peak anaerobic power) activities also involve short-burst, high-intensity movements, but they last from 15 seconds up to 3 minutes. Anaerobic capacity activities produce high levels of metabolic products such as lactic acid, and challenge the person’s tolerance of an acid–base imbalance.

Aerobic power activities require high levels of oxygen delivery to the working muscles and last from 3 to 15 minutes. Aerobic power is

associated with the measurement or estimation of maximal oxygen uptake ( O2max), which is the maximal ability of the body to use oxygen to produce energy for performing work. Figure 2.5 illustrates the concept of exercise intensity (running) and O2max for a trained and an untrained man. Aerobic capacity activities stress the ability to maintain high percentages of O2max for extended periods of time (e.g., 20 minutes or longer). An average untrained person should be able to work for this amount of time at about 50% of O2max aerobic capacity prior to a program of physical activity or exercise, but can increase this to 70% (or higher) after several weeks. Improvements in aerobic capacity can improve cardiorespiratory economy (i.e., energy or oxygen cost at a given workload or speed) by recruiting less muscle mass to perform the same amount of work.

Figure 2.5   Relationship between exercise intensity (running speed) and O2max for a trained and an untrained man. Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport and Exercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 130.

INTENSITY Intensity can be determined for a physical activity or exercise in a variety of ways based on whether the activity is more aerobic or more anaerobic. For example, a person can obviously work at a higher intensity for a shorter period of time (e.g., a few seconds) than for several minutes. Intensity is the primary FITT variable that affects the total caloric expenditure of physical activity or exercise when the duration is held constant. Intensity level also affects the risk of injury if it is set too high for the current level of conditioning of an individual or a population.

Intensities can be classified as light, moderate, or vigorous, and as absolute or relative. The Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018) generally classifies physical activity or exercise as light intensity when activity requires 1.6 to less than 3.0 METs, such as walking at a slow pace (<2 mph [<3.2 km/h]) or cooking activities. An activity or exercise is of moderate intensity when one is working between 3 and 6 METs, and an activity is considered vigorous intensity when the person is working above 6 METs. Absolute intensity can be expressed in kcals/min, in METs, or as walking at 4 miles per hour (6.4 km/h) or jogging at 5 miles per hour (8 km/h). For resistance exercise, absolute intensity can be expressed as the amount of weight lifted or force exerted (e.g., in pounds or kilograms). Absolute intensity may also be classified into categories such as low, moderate, vigorous, and maximal. Table 2.1 shows the classification of physical activity levels from the Physical Activity Guidelines for Americans (USDHHS 2008).

Relative intensity is usually expressed as a percentage of aerobic power ( O2max) or as a percentage of measured heart rate or heart rate reserve (maximal heart rate − resting heart rate). Perceived exertion ratings (i.e., how hard people feel they are working, from light to very hard) can also be used as a relative intensity measure along with a percentage of 1-repetition maximum

(i.e., the maximum a person can lift in one trial) for weightlifting activities.

The Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, pp. D-3, D-4, Table D-1) contains classifications of physical activity and exercise intensities that show how the intensity of physical activity and exercise is significantly affected by the differences of O2max of individuals or populations. As shown in figure 2.6, an adult with a higher-than-average O2max of 14 METs who is walking at 3 miles per hour (4.8 km/h) is working at a relative intensity of 24% of her max (low). However, an adult with a low O2max of 6 METs is working at a relative intensity of 55% of his max (hard). An adult with a low aerobic capacity of 4 METs cannot walk at 4 miles per hour (6.4 km/h) for very long because the intensity exceeds O2max and the activity becomes mostly anaerobic; this workload requires at least a 5 MET absolute intensity.

A full discussion of the many ways to determine physical activity and exercise intensities is beyond the scope of this text. However, the common aerobic and anaerobic methods used for determining intensity for exercise prescriptions, which also apply to physical activity and exercise interventions for populations, are discussed next.

Table 2.1   Classification of Total Weekly Amounts of Aerobic Physical Activity Into Four Categories

Level of physical activity

Range of moderate- intensity minutes per week

Summary of overall health benefits Comment

Inactive No activity beyond baseline

None Being inactive is unhealthy.

Low Activity beyond baseline but fewer than 150 minutes a week

Some Low levels of activity are clearly preferable to an inactive lifestyle.

Medium 150 minutes to 300 minutes a week

Substantial Activity at the high end of this range has additional and more extensive health benefits than activity at the low end.

High More than 300 minutes a week

Additional Current science does not allow researchers to identify an upper limit of activity above which there are no additional health benefits.

Reprinted from USDHH, PAGA (2008).

PERCENTAGE OF MAXIMAL HEART RATE The percentage of maximal heart rate (MHR) method is an aerobic method based on the simple exercise physiology assumption that predicted MHR is equal to 220 minus age (generally the error is plus or minus 10 beats per minute, or bpm). You then multiply MHR by the percentage of the intensity desired. For example, if a goal is to have a 30-year-old man work at 60 to 80% of his MHR, the calculation would be as follows: 220 − 30 = 190 × 0.6 and 190 × 0.8, or an exercise heart rate between 114 bpm and 152 bpm. This method is convenient to use with beginners who may be at higher health risk, because it is conservative (when using lower percentages) and yields lower intensities than some other methods do.

Figure 2.6   Relative intensity of walking at 3 mph (4.8 km/h, 3.3 METs) and 4 mph (6.4 km/h, 5.0 METs) expressed as a percentage of O2max for adults with an exercise capacity ranging from 4 to 14 METs. Reprinted from USDHH, PAGA (2008).

PERCENTAGE OF MAXIMAL HEART RATE RESERVE, OR TARGET HEART RATE The percentage of MHR reserve, or target heart rate (THR), method is an aerobic method also based on simple MHR prediction; it involves subtracting resting heart rate (RHR) according to the following equation:

MHR reserve = MHR − RHR

THR = (MHR − RHR) × (desired percentage of intensity, e.g. 60%) + RHR

A 40-year-old with an RHR of 80 who works at 60 to 70% of MHR reserve would yield the following equation: THR = (180 − 80) × 0.6 + 80 = 140 bpm and THR = (180 − 80) × 0.7 + 80 = 150 bpm for a THR range of 140 to 150 bpm. This formula is called the Karvonen formula in honor of the exercise physiologist who first described it in the late 1950s. This method is often used for those who are familiar with regular exercise and at low health risk, because it provides higher intensities than a simple percentage of MHR.

METABOLIC EQUIVALENTS The metabolic equivalent (MET) aerobic method is based on the concept described earlier in this chapter that, for healthy adults, 1 MET = 3.5 ml . kg–1 . min–1. As you have learned, physical activity and exercise can be classified as light, moderate, or vigorous intensity based on the MET level required to perform specific movements. The Physical Activity Guidelines Advisory Committee Report has a listing of activities and exercises that require at least 6 METs’ worth of intensity (USDHHS, PAGAC 2008, pp.D-5, D-6).

Once the O2max of an individual or a population is measured (usually on a maximal exercise test) or estimated (see chapter 5 for more on measuring or estimating O2max), it can be expressed in METs. A percentage of the maximal METs achieved can then be used to calculate an initial or follow-up exercise training intensity. A person with a O2max of 12 METs might train at 50% of his maximum, or at 6 METs. Physical activity practitioners commonly use this method to help people train at a certain intensity.

Scientific studies show us that it is never too late to begin a physical activity program. What are some reasons that physical activity is important throughout life?

PERCENTAGE OF MAXIMAL OXYGEN UPTAKE

As with the MET determination just discussed, if you know the individual’s or population’s maximal oxygen uptake ( O2max), you can calculate an intensity for physical activity or exercise based on a percentage of that max. For example, if the goal is to train a group at 70% of O2max, and the group’s average O2max is 35 ml . kg–1 . min–1 (or 10 METs), you would use the calculation 35 ml . kg–1 . min–1 × 0.7 = 24.5 ml . kg–1 . min–1 (or 7 METs). Figure 2.7 illustrates how to use the linear relationship between heart rate (HR) and O2max to determine a representative physical activity or exercise HR response (75% of O2max) based on the percentage of O2max prescribed. This method is still one of the most popular methods used by exercise physiologists to determine exercise intensities.

KILOCALORIES PER MINUTE OR PER HOUR The kilocalories per minute or kilocalories per hour aerobic method has become one of the most popular methods to determine physical activity and exercise intensity, particularly in weight loss and weight maintenance programs. The conversion factor, 1 liter of oxygen consumed being equal to ~5 kcals/min, is used to determine the total kcals expended for a bout of physical activity or exercise. For example, if someone weighs 80 kilograms (176 lb) and is working at 35 ml . kg–1 . min–1 (or 10 METs), you could calculate caloric expenditure as follows:

35 ml . kg–1 . min–1 × weight [in kg] × 1,000 = oxygen uptake in liters/min, or 35 × 80 / 1,000 = 2.8 liters/min.

Then, converting to kcals/min, you would have 2.8 liters/min × ~5 kcals/min, or 14 kcals/min, or 840 kcals/h (14 × 60).

Figure 2.7   Linear relationship between HR and O2max with increasing rates of work and the HR equivalent to a set percentage (75%) of O2max. Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport and Exercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 203.

PERCEIVED EXERTION SCALES AND THE TALK TEST The perceived exertion (PE) scale and talk test methods require that people evaluate how hard they are working, or determine whether they can carry on a conversation at a given intensity of work. Figure 2.8 shows a PE scale called the OMNI-Walk/Run Scale for adults; it is a simple way for practitioners to teach people how to rate their physical activity and exercise intensity. For example, an OMNI scale

rating of 7 for an untrained adult would indicate that the person is working “somewhat hard” to “hard.” Scales such as the OMNI scale can be used to help people focus on achieving moderate to vigorous physical activity or exercise intensities by achieving PE levels ≥4 (PEs of 4 to 6 = moderate physical activity or exercise, and PE > 6 = vigorous physical activity or exercise). The talk test basically tells practitioners whether someone is working at a comfortable level (i.e., can carry on a conversation easily) or struggling (i.e., cannot carry on a conversation comfortably).

PE scales and the talk test are very practical because people can describe their feelings about their bodily responses to physical activity or exercise (e.g., breathing, muscle pain, sweating). However, they are complicated by various physiological factors that influence the ratings such as lactate and ventilatory thresholds (see ACSM 2018 for more on the lactate and ventilatory thresholds). Exercise practitioners should make sure that the people using these methods have experience with them. Those who don’t (especially youth) often underestimate how hard they are working.

REPETITION MAXIMUM The most commonly used anaerobic method related to weightlifting as a resistance training mode is the 1-repetition maximum (1RM). For example, a person who can lift 100 pounds (45.5 kg) over his head one time and no more has a 1RM of 100 pounds. This would be called his absolute strength for that lift. Relative strength would reflect his 1RM divided by his body weight as stated in the Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, Table D-1) as discussed earlier.

Figure 2.8   OMNI-Walk/Run Scale of perceived exertion for adults. Reprinted by permission from R.J. Robertson, Perceived Exertion for Practitioners: Rating Effort With the OMNI Picture System (Champaign, IL: Human Kinetics, 2004), 142

Because performing a 1RM can be challenging for inexperienced weightlifters or older adults, many practitioners have the person perform a 5RM (maximum amount of weight lifted five times) or 10RM (maximum amount of weight lifted 10 times), which is safer and more comfortable. Normative standards are available for 1RM by age and sex (see ACSM 2018), which can be used for resistance performance evaluations of individuals or populations. In addition, values from 5RM and 10RM can be used to predict 1RM abilities, which can then be used to develop exercise prescriptions or physical activity or exercise plans.

WORKLOAD The workload anaerobic method considers factors that affect resistance exercise such as speed, muscular strength, muscular endurance, power, and the specific muscle groups involved. Several resources (e.g., ACSM 2018) detail the specifics of resistance training programs for various individuals and populations. However, all resistance training regimens should consider the following: emphasis (e.g., strength or muscular endurance); participant’s level (e.g., beginner versus advanced); percentage of 1RM, 5RM, or 10RM; number of sets and number of repetitions per set (e.g., 10

repetitions per set, for three sets); velocity of movement (e.g., slow, moderate, or fast); rest between sets (see the following discussion of time); and the frequency of participation per week (see the following discussion of frequency).

TIME Table 2.2 provides some general recommendations based on traditional exercise prescription programming for determining the time (duration) of types of physical activity and exercise activities. The table includes recommendations for achieving basic functional health (a minimal long-term goal) as well as high performance.

FREQUENCY Table 2.3 provides some general recommendations for the frequency of types of physical activity and exercise activities. It includes recommendations for achieving basic functional health (a minimal long-term goal) as well as high performance.

Table 2.2   General Recommendations for Time for Achieving Functional Health or High Performance

Type of activity Functional health/physical function High performance

Aerobic 20-60 min 20-120 min

Anaerobic 20-30 min 20-120 min

Aerobic and anaerobic

Based on practical goal setting

Based on practical goal setting

Recommendations can be achieved continuously or accumulated in multiple bouts per day.

Table 2.3   General Recommendations for Frequency for Achieving Functional Health or High Performance

Type of activity Functional health/physical function High performance

Aerobic 3-5 days/week 5-7 days/week

Anaerobic 2-3 days/week 3-4 days/week

Aerobic and anaerobic

Based on practical goal setting

Based on practical goal setting

Recommendations can be achieved continuously or accumulated in multiple bouts per day.

APPLYING PHYSICAL ACTIVITY AND EXERCISE TRAINING PRINCIPLES Once you are comfortable using the FITT concept, it would be helpful to learn how to apply exercise science principles and practice them to improve the exercise training adaptations of individuals and populations. The exercise principles previously defined are explained in more detail in this section.

PRACTICAL GOAL SETTING When determining the needs and goals of an individual or group, a needs assessment should be conducted that includes practical and achievable goals for physical activity and exercise. Use the concepts and strategies of behavioral science theoretical models described in chapter 13 to fine-tune your goal-setting skills. A good goal for a group would be to achieve the minimal recommendations of the Physical Activity Guidelines for Americans (USDHHS 2008, 2018).

GENETICS AND INDIVIDUAL VARIATION The genetics of an individual or a population can affect the ability to benefit from physical activity and exercise. Genetics also accounts for adaptation rates and the maximal potential for adaptations. Obviously, there are variations for levels of change within individuals and populations for important health fitness variables similar to the

variance in the curves such as that for physical activity, exercise, and health outcomes previously shown in figure 2.4.

Figure 2.9 shows five genetic and training variations that you might see in relationship to the benefits of physical activity or exercise training over time (e.g., six months). Curve 3 represents a profile of adaptation to physical activity and exercise that most practitioners expect to see; however, many people do not respond in this fashion. You will need to evaluate your physical activity and exercise plans regularly to adjust them to facilitate further gains in health outcomes.

CASE STUDY

TOTAL PHYSICAL ACTIVITY PER WEEK The amount of physical activity and exercise performed for a given period of time (see USDHHS, PAGAC 2008, section D, for more) can be determined by using the absolute intensity, the time or duration, and the frequency. As shown in table 2.4, the dose of physical activity and exercise can be expressed in minutes or hours per week (of moderate-intensity, vigorous- intensity, or moderate- plus vigorous-intensity activity), or in terms of distance walked, jogged, or run per day or week. The amount of physical activity and exercise can also be expressed in kilocalories per day or week, kilocalories per kilogram of body weight per day or week, or MET-minutes or MET-hours per day or week. By using the concept of relative intensity, time or duration, and frequency (e.g., 30 minutes at 70% of predicted MHR five times per week for 24 weeks), one can compare and generalize across various FITT amounts to determine recommendations for physical activity and exercise in population interventions.

Table 2.4 shows that if Albert participated in physical activity (walking at 3 mph, or 4.8 km/h, at moderate intensity) for 2.5 hours per week (a minimum recommendation), he would average 495 MET-minutes per week, 8.25 MET-hours per week, or the equivalent of 7.5 miles (12 km) per week. If Albert weighed 165 pounds (75 kg), his energy expenditure would be 620 kcals per week. If Albert were active at the same intensity for 5 hours per week, he would average 990 MET-minutes per week, 16.5 MET-hours per week, or the equivalent of 15 miles (24 km) per week, and his energy expenditure would be 1,240 kcals per week.

If Albert in the preceding example were able to participate in physical activity or exercise at a vigorous intensity such as jogging at 7 miles per hour (11 km/h) for 2.5 hours per week, he would expend considerably more calories per week (620 kcals versus 2,155 kcals based on gross energy expenditure values), which reinforces the importance of intensity when determining FITT variables and setting goals for individuals and populations.

MOTIVATION

Motivation refers to the importance of the behavioral reinforcement of intrinsic motivation goals that promote regular participation in physical activity or exercise. Chapter 13 describes behavioral models practitioners commonly use to encourage and maintain motivation levels.

Figure 2.9   Training adaptation curves for five individuals.

TEACHING MODEL The teaching model refers to the need for practitioners to be effective teachers who use educational strategies or logic models (see chapter 15 for more about logic models) to motivate target populations and reinforce the benefits of physical activity and exercise. Figure 2.10 provides an example of a simple teaching model a practitioner can use to work with an individual or population to minimize barriers that might negatively affect the adoption of regular physical activity. Practitioners also can work to maximize those factors for specific goals and outcomes that positively promote

the adoption of regular physical activity and exercise along the physical activity and exercise continuum.

Figure 2.10    Factors influencing an individual to adopt regular low to high levels of physical activity and exercise.

FITNESS EVALUATION Evaluating fitness levels prior to initiating physical activity and exercise programs is valuable for determining the effectiveness of the programs. The level of evaluation required will vary greatly depending on the physical abilities of the target population and its goals and needs. Performing fitness evaluations in conjunction with determining goals will help ensure that the program meets the needs of the target population.

OVERLOAD The overload principle refers to the fact that improvements in health and physical fitness are directly related to increases in FITT variables by gradually increasing the physical stress on the body. Changes in overload should be considered in conjunction with genetics and individual variation to ensure that people have adapted

to current training levels before changing any FITT variables. Too little or too much change in progressive overload will not produce the desired results. In most cases, changing all the FITT variables at once is unwise, because people do not have enough time to adjust to new workloads, which can result in injury or burnout. Applying the overload principle correctly requires a lot of experience because of the great variability of physical adaptations to physical activity and exercise in individuals and populations.

SPECIFICITY The specificity principle refers to the fact that changes in health and fitness depend on adjusting FITT variables for the desired adaptations. Whether working with individuals or populations, it is important to consider the specific physical demands of the physical activity or exercise plan. For example, a plan designed to help sedentary, high-health-risk middle-aged men reach minimal levels of functional fitness would be significantly different from one designed to help young, experienced adult women runners train to complete a marathon. The two goals are obviously very different and would require very different manipulation of FITT variables to achieve success.

MODIFICATIONS Exercise prescriptions and physical activity and exercise plans often need to be modified based on individual, population, and environmental changes. Variables that may require a modification of a physical activity or exercise plan include injury, illness, medications, lack of recovery, and symptoms of overtraining. A modification might involve changing FITT variables to allow a person or population to continue with the plan, but at adjusted levels; this can minimize the risk of complete relapse (stopping and not starting again). Learning how to modify physical activity and exercise plans will encourage compliance (see the discussion of compliance for more).

PROGRESSION/ADAPTATION Progression/adaptation refers to cycling (or varying) the FITT variables, volume of physical activity and exercise, and recovery time. Figure 2.11 illustrates a simple progression/adaptation curve that shows adaptation and progression of health and fitness outcomes over 30 weeks of participation. Progression and adaptation improvements depend on the starting health or fitness levels of the person or population (usually, the lower the starting health or fitness level, the greater the initial gains). Normal progression/adaptation curves include an initial stage, a plateau stage, and an improvement stage.

Figure 2.11   Simple progression/adaptation example.

Training plateaus are periods when little, if any, improvement in fitness occurs. The rate of improvement can be influenced by effective progression/adaptation of training. It is important to be able to recognize the plateau phenomenon and use effective behavioral

(see chapter 13 for more information) and FITT strategies to help people remain motivated to maintain or increase their physical activity and exercise behaviors. This is because lack of improvement may promote relapse. There are numerous ways to apply the progression/adaptation principle to physical activity and exercise plans; the references at the end of the chapter and the e-media links in the web resource offer more information about FITT variables and seasonal variations associated with progression/adaptation.

OVERTRAINING Overtraining can produce abnormal physical and psychological responses. It is defined as doing too much physical activity or exercise without taking the time to recover appropriately. Overtraining is associated with increased overuse injuries (muscle and skeletal problems) and addictive behaviors that are directly related to relapses and lower exercise compliance levels. Symptoms of overtraining include excessive fatigue, unusual muscle soreness, a lower immune response (high incidence of upper respiratory infections), insomnia, weight loss, increased resting heart rates, and feeling mentally burnt out.

Chronic overtraining that occurs over several weeks or months can lead to burnout and is often associated with permanent physical activity or exercise relapses. You can help individuals or populations avoid overtraining by encouraging them to recognize the signs of addiction to exercise (e.g., the notion that if a little bit is good, more is better) and to take a short break (two or three days) in their physical activity or exercise routine if such signs are evident.

DETRAINING Detraining refers to the loss of health or fitness following the cessation of a regular program of physical activity or exercise. Health and fitness benefits often decrease at rates similar to those at which they accrued; however, significant variability can occur between specific factors (e.g., osteoporosis benefits versus functional health

benefits; see figure 2.4). Significant detraining does not occur in a day or two, but people who stop all regular physical activity or exercise for two weeks to a month will notice losses in their aerobic and anaerobic abilities.

Bed rest is an extreme example of detraining. Dr. Jere Mitchell and his colleagues from Southwestern Medical School in Dallas, Texas (McGuire et al. 2001), reported in a classic study that 20 days of complete bed rest in 20-year-old males caused a greater deterioration in physical cardiorespiratory capacity than did 30 years of aging. Some research suggests that detraining effects can be minimized by continuing to be physically active even at a reduced volume of training before resuming a regular schedule of participation.

RECOVERY The rate at which people or populations can recover is influenced by FITT variables, age, past experience with physical activity and exercise, environmental factors such as heat and altitude, average amount of sleep, and the abilities to rehydrate and consume enough energy to meet physical activity and exercise demands. Generally, at least 24 hours are needed to properly recover from high-intensity exercise, especially if someone is active daily. People who are just trying to meet the minimum guidelines for moderate and vigorous physical activity of 2.5 hours per week should not have much trouble recovering unless they have existing musculoskeletal injuries, disabilities, or complicating medical conditions.

COMPLIANCE Compliance refers to people’s ability to continue to participate in regular physical activity or exercise programming. Following are barriers that can negatively affect compliance:

Lack of time Low potential for physical adaptations

Poor mobility Unrealistic physical activity or exercise goals or expectations Lack of knowledge about physical activity and exercise Low perceived competency with physical activity Injury Past negative experiences with physical activity or exercise

LEADER PROFILE Ho Han, PhD

Why and how did you get into the field of Physical Activity and Public Health? My initial research interests in exercise science and health behavior began my senior year at Korea National Sport University in South Korea. During my undergraduate years, I specialized in taekwondo, a traditional Korean martial art, and was excited to study exercise and metabolic responses in humans. Professor Bongan Kwon encouraged me to study abroad in the United States, and I went to graduate school for my master’s degree in exercise physiology at the University of Texas at Austin. During the program, my academic advisor, Dr. John L. Ivy, suggested I take a graduate course taught by two highly renowned professors in the fields of exercise physiology (Dr. John L. Ivy) and epidemiology (Dr. Harold W. Kohl). In this class, I realized for the first time that a lack of physical activity was an epidemiologic issue that had

to be addressed more seriously at the population level. In order to learn more about physical activity in public health, I shifted my major to the health behavior and health education doctoral program under the supervision of Dr. Kohl. In the doctoral program, I learned a great deal about physical activity epidemiology and various strategies to increase physical activity including theory- based intervention programs, community-wide campaigns, and the built environment. This academic background influenced my current career in teaching and research at Oklahoma State University.

Did any one person have a major influence on your career? How? A number of mentors and advisors have had an influence on my career, but one primary influence was Dr. Harold W. Kohl. My past and current research interests in physical activity and public health developed and continued after meeting Dr. Kohl. As an international scholar, I faced many challenges during my academic years, especially due to the language barrier. It was quite difficult for me to adapt to a new field of physical activity and public health using a foreign language. He showed enduring patience and provided concrete research and academic resources that guided me to become a successful, independent researcher. I will be endlessly grateful to Dr. Kohl for his efforts and guidance.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My overall research interests are physical activity measurement and community-wide interventions to increase physical activity levels. One of my current research projects is to learn how to develop a clear and effective physical activity prescription using a step-based metric to help more people achieve the recommended amount of physical activity and, in turn, improve their quality of life. I am also very interested in the various health outcomes associated with physical activity for the purpose of disease prevention, treatment, and rehabilitation.

Why do you do what you do?

Despite the substantial health impact of physical activity on all-cause mortality and cardiovascular disease mortality, physical inactivity is now described as a pandemic—a leading cause of death in the world. One of the best ways to increase individual physical activity levels may be to provide a physical activity prescription that is more understandable and easier to follow compared to the ones currently available. All of the efforts on my current projects are to facilitate the translation of research findings into real-life situations.

What are two key issues that must be addressed by 2030? As the independent health risks of a sedentary behavior lifestyle have become a well-known issue in public health, an effort to reduce sedentary behavior has to occur while simultaneously promoting physical activity (e.g., teaching behavior replacement skills or developing a guideline for sedentary behavior). In addition, more effective population-wide interventions need to be implemented. Technology-based interventions for providing feedback, coaching and goal-setting, and social networking could be a great option.

Although compliance is presented as the last training consideration, it is one of the most important because, without it, even the best physical activity or exercise plan will fail. By minimizing barriers to compliance the opportunities for developing successful physical activity and exercise plans are significantly enhanced.

HEALTH AND FITNESS BENEFITS OF PHYSICAL ACTIVITY AND EXERCISE Numerous health, fitness, and performance benefits of physical activity and exercise have been reported in the scientific literature. A complete list is beyond the scope of this chapter, but some specifics are provided in part II of the text. Some of the general benefits gleaned from the Physical Activity Guidelines for Americans (USDHHS 2018) are provided in the sidebar Health Benefits Associated With Regular Physical Activity.

As noted in the Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018), people who are interested in training programs to increase performance-related fitness (e.g., agility, balance, coordination, speed, power, and reaction time) should seek advice from professionals specializing in sport skill activities, because people with these interests are already more active than the guidelines recommend for health and fitness. People who are interested in performance-related fitness may also be at higher risk for injury related to physical activity and exercise, and as such should consider factors that will help them remain safe and active (see chapter 10 for more information).

HEALTH BENEFITS ASSOCIATED WITH REGULAR PHYSICAL ACTIVITY Children and Adolescents

Strong Evidence

Improved cardiorespiratory and muscular fitness

Improved bone health

Improved cardiovascular and metabolic health

biomarkers

Favorable body composition

Moderate Evidence

Reduced symptoms of depression

Adults and Older Adults

Strong Evidence

Lower risk of early death

Lower risk of coronary heart disease

Lower risk of stroke

Lower risk of high blood pressure

Lower risk of adverse blood lipid profile

Lower risk of type 2 diabetes

Lower risk of metabolic syndrome

Lower risk of colon cancer

Lower risk of breast cancer

Prevention of weight gain

Weight loss, particularly when combined with reduced

calorie intake

Improved cardiorespiratory and muscular fitness

Prevention of falls

Reduced depression

Better cognitive function (for older adults)

Moderate to Strong Evidence

Better functional health (for older adults)

Reduced abdominal obesity

Moderate Evidence

Lower risk of hip fracture

Lower risk of lung cancer

Lower risk of endometrial cancer

Weight maintenance after weight loss

Increased bone density

Improved sleep quality

Note: The Advisory Committee rated the evidence of health benefits of physical activity as strong, moderate, or weak. To do so, the Committee considered the type, number, and quality of studies available, as well as consistency of findings across studies that addressed each outcome. The Committee also considered evidence for causality and dose response in assigning the strength-of-evidence rating.

Reprinted from USDHHS (2008, p. 9).

CHAPTER WRAP-UP

WHAT YOU NEED TO KNOW

Definitions for terms like sedentary behavior, sedentary activity, physical activity, exercise, physical fitness, and the physical activity and exercise continuum are all important to understand and to use for effective communication in the field of physical activity and public health. The integration of the concepts of kinesiology related to public health is based primarily on the Physical Activity Guidelines for Americans (USDHHS 2008, 2018) and the Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018). The study of kinesiology includes the major exercise sciences of exercise physiology, the movement sciences, and sport and exercise psychology. An understanding and integration of multiple kinesiology subdisciplines will help practitioners be successful at developing physical activity and exercise plans to promote and achieve public health goals. Numerous general and specific health, fitness, and performance benefits of participating in physical activity and exercise have been reported in the scientific literature. The Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018) includes real-life case studies of children, adolescents, adults, and older adults who have become and remained physically active. By learning how to integrate the physical training concepts presented in the chapter, you can optimize the success of your physical activity and exercise program. An understanding and application of training theory can help practitioners understand traditional training models designed for maximizing performance versus new strategies for developing physical activity and exercise plans for promoting

positive health outcomes for not only individuals, but populations as well. The volume of physical activity and exercise significantly affects dose-response health benefits. It is important to understand information from the exercise sciences (data-based research literature outcomes) and apply it (the clinical practice of using training principles based on knowledge and experiences) effectively to improve health, fitness, and performance. The intensity of physical activity and exercise when duration is held constant is the most important FITT variable relative to caloric expenditure (volume) per minute, per hour, per day, or per week. Intensities are often classified in absolute terms (i.e., energy or work required to do an activity without accounting for the person’s physiological capacity) or relative terms (i.e., taking into account the person’s exercise capacity, such as a percentage of aerobic capacity). Light physical activity is defined as activity requiring 1.6 to less than 3 METs, such as walking at a slow pace (<2 mph [3.2 km/h]) or cooking activities. Moderate-intensity physical activity or exercise is categorized as working between 3 and 6 METs, whereas vigorous-intensity physical activity is defined as working at greater than 6 METs. The amount of physical activity and exercise performed can be determined by using the absolute intensity or relative intensity, the time or duration, and the frequency. The art of applying physical activity and exercise training principles can help practitioners minimize barriers to meeting public health recommendations for participation in regular physical activity and exercise.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Ainsworth BE, Haskell WL, Whitt MC, Irwin ML, Swartz AM, Strath

SJ, O’Brien WL, Bassett DR, Jr., Schmitz KH, Emplaincourt PO, et al. 2000. Compendium of physical activities: An update of activity codes and MET intensities. Medicine & Science in Sports & Exercise 32 (9 Suppl): S498-S504.

American College of Sports Medicine. 2018. ACSM’s Guidelines for Exercise Testing and Prescription, 10th ed. Philadelphia: Lippincott Williams & Wilkins.

Blair SN, Kohl HW III, Paffenbarger RS Jr., Clark DG, Cooper KH, Gibbons LW. 1989. Physical fitness and all-cause mortality. A prospective study of healthy men and women. Journal of the American Medical Association 262 (17): 2395-2401.

Caspersen CJ, Powell KE, Christenson GM. 1985. Physical activity, exercise, and physical fitness: Definitions and distinctions for health-related research. Public Health Reports 100: 126-131.

Haskell WL, et al. 2007. Physical activity and public health: Updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Medicine & Science in Sports & Exercise 39: 1423-1434.

Kenney WL, Wilmore JH, Costill DL. 2019. Physiology of Sport and Exercise, 7th ed. Champaign, IL: Human Kinetics.

McGuire DK, Levine BD, Williamson W, Snell PG, Blomqvist G, Saltin B, Mitchell J. 2001. A 30-year follow-up of the Dallas Bed

Rest and Training Study: I, effect of age on the cardiovascular responses to exercise. Circulation 104: 1350-1357.

Murray T. D., Eldridge J. A., and Kohl, H. W. III. 2019. Foundations of Kinesiology: A Modern Integrated Approach. Boston, MA: Cengage Learning.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.4, 1.4.2, 2.22, 2.3.3, 2.5.2, 3.1.3, 5.1.1, 6.1.3, 6.1.4, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.3.3, 6.3.5, 6.4.1, 6.4.2, 6.5.4, 6.5.5

CHAPTER 3 Integrating Public Health and Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The history of physical activity and public health »  How science is translated into practice in physical activity

and public health »  How the application of scientific findings differentiates

physical activity and public health from other areas such as medicine and exercise physiology

»  Knowledge, skills, and aptitudes for careers in physical activity and public health

OPENING QUESTIONS »  What is the intersection between kinesiology and public

health?

»  Why is defining this intersection important? »  Is there a career for you in physical activity and public

health?

Physical activity and public health—what do you think of when you read that phrase? Elite Olympic athletes who look to be in ideal health? Masters-level swimmers who swim a mile each day because they enjoy it? Women who work at a factory and spend their lunch hour each day walking 2 miles (3.2 km) together? Construction workers who lift, bend, stoop, and carry loads all day? Kids in a physical education class jumping rope? If you answered yes to all of these questions, you are right. Physical activity and public health is a field of study that looks at the health effects and risks of physical activity and ways to help people become active and maintain a healthy level of activity throughout their lives.

Public health is the science and practice of protecting, promoting, and improving the health of populations and communities. An overview of public health concepts was presented in chapter 1. Although individual people are important to health care professionals, public health is primarily interested in the health of communities or groups of people. When we think of public health, notable achievements such as vaccinations against disease, quarantine rules for controlling disease outbreaks, reductions in deaths resulting from motor vehicle accidents, fluoridation of public water supplies to improve dental health, and food safety and restaurant inspections to reduce food-borne illnesses come to mind.

HISTORY OF PHYSICAL ACTIVITY AND PUBLIC HEALTH Although there is evidence that people understood that exercise was important for health all the way back in ancient Greece, the formal study of the health effects of physical activity is much newer. Even newer is what we now know about how to help people change their behaviors to take advantage of all the health benefits of a physically active way of life.

An understanding of the evolution of the field of physical activity and public health can come from learning how the two fields of exercise science and public health science evolved independently in the 20th century. Exercise science was a developing field in the early 1900s, and much of what we now know about exercise physiology, biomechanics, and sport performance can be traced to early work in exercise science. Fundamental understandings of how oxygen is delivered to working muscles through the cardiovascular system, how carbon dioxide is produced and expelled during exercise, and how glucose (sugar) is metabolized as the body moves resulted in prominent steps forward in the early part of the last century.

The 20th century also witnessed the expansion of personal physical education from having a medical focus in the 1800s to providing sport and games to the masses. Developing fitness for military service was also a prominent role for physical education. The concept of play as a means to promote health also grew during the 20th century.

In the 20th century, life expectancy in the United States increased by 30 years. Even though fundamental practices of personal and community hygiene and quarantine, and the development of vital statistics systems, occurred much earlier, these were modified and updated in the 20th century. Penicillin, the first antibiotic medicine used to control bacterial infections, was discovered in 1928 by Scottish scientist Alexander Fleming. Vaccine development and mass vaccination efforts helped to stem and nearly eliminate serious infectious diseases such as polio and smallpox. Major advances in food safety, including handling and storage, were made in the 20th

century, making the food supply safer and reducing the risk of pathogens being carried in food to humans and animals.

Epidemiology, the basic science of public health, is concerned with the study of the causes and consequences of disease and disability in human populations. Initially developed to help people understand how to identify and prevent infectious diseases such as cholera and tuberculosis prior to 1900, epidemiology has evolved to address contemporary health burdens as well, such as heart diseases, cancers, motor vehicle accidents, and air pollution. Major advances in epidemiology also occurred in the 20th century with the emergence of new study designs and observational techniques to assess health outcomes, particularly those related to chronic diseases in populations. Further, our ability to collect, process, and analyze data improved with the advent of computing.

The conditions were ripe in the 20th century for the two fields of exercise science and public health to come together. In fact, such a merger began with the publication of a study conducted in London in 1953. A young epidemiologist named Jeremy N. Morris was interested in heart disease and its causes and consequences. Dr. Morris chose to study workers employed by the London transport system. It was a large group of (mostly) men who worked all day moving people around the city of London. Dr. Morris was particularly interested in the amount of physical activity the men got in the course of their jobs and how that related to their risk of having a heart attack.

Figure 3.1   The Routemaster bus, a laboratory of early studies of physical activity and health.

A popular form of public transportation in London in the late 1940s and 1950s was the legendary Routemaster (double-decker) bus (see figure 3.1). Hundreds of these buses operated throughout the city. Although similar buses operate in London today, in the 1950s there were no computers, magnetic card readers, or other conveniences. Dr. Morris was able to separate the men he was studying into two groups: the bus drivers who were inactive all day long because they were sitting and driving the buses, and the conductors who were walking up and down the stairs of the buses taking tickets from riders all day (Morris et al. 1953; see figure 3.2). Morris found that the physically active conductors had significantly lower rates of coronary heart disease then the less active drivers.

Although these findings may seem fairly straightforward now, at the time they were quite revolutionary. A shift in the paradigm had begun as physical activity for health began to be placed alongside exercise for performance.

The exercise/heart hypothesis, now more of an accepted fact than a hypothesis, essentially was that people who exercised more

frequently had healthier, better functioning circulatory systems than similar people who did not exercise. This physiological benefit resulted in a lower risk of death from heart disease among those who were more active. Dr. Morris went on to publish further studies of occupational physical activity (i.e., physical activity that results from the job one performs) and he is widely viewed today as the grandfather of the field of physical activity and public health.

Figure 3.2   Incidence of coronary heart disease in London bus drivers and conductors aged 35 to 64. London Transport Executive 1949-1950. Data from Morris et al. (1953).

Following Dr. Morris, and equally, if not more, effective, was Dr. Ralph S. Paffenbarger Jr. (see figure 3.3). Dr. Paffenbarger was trained in medicine and studied infectious diseases early in his career. He was extremely influenced by Dr. Morris’ work on the London transport workers and set out to improve our understanding of the exercise/heart hypothesis from a public health point of view. As a result of his many influential studies of college alumni and

longshoremen, Dr. Paffenbarger was able to more precisely identify the amounts and types of physical activity that were associated with improved health. Thus was born the field of physical activity and public health.

Figure 3.3   Dr. Ralph Paffenbarger and Dr. Jeremy Morris, trailblazers in physical activity and public health.

Into the 1970s and 1980s, observational studies of physical activity and health outcomes continued to emerge, as did studies of exercise dose, performance, and the physiological effects of the two. Researchers began to quantify the substantial health benefits of physical activity (and the risks of inactivity); some of these many benefits are shown in chapter 2. Moreover, during this time it became clear that many people throughout the world were not physically active at levels that could reduce their risk of disease, disability, or both. Populations, not just individuals, were not as healthy as they could be because of physical inactivity. Suddenly, an exercise and performance problem became a physical activity and public health problem (see figure 3.4).

With the scientific cooperation of exercise science and epidemiology taking hold, additional disciplines began to focus on physical activity and health. Specifically, in the 1990s, behavioral sciences and environmental health sciences were added to the picture. Behavioral sciences began to explore the determinants of physical activity and inactivity and to investigate how inactive people could adopt and maintain healthier behaviors. More recently, environmental health sciences have begun to explore the role that place and the built environment play in encouraging or discouraging physical activity behaviors. Taken together, a new subdiscipline, physical activity and public health, has emerged (see figure 3.5).

Figure 3.4   The merger of kinesiology and epidemiology to create physical activity and public health.

Figure 3.5   Physical activity and public health—the emergence of a subdiscipline.

ROLE OF PHYSICAL ACTIVITY IN CHRONIC DISEASE DEVELOPMENT Much of the interest in physical activity and public health arises from the role physical activity plays in the prevention and treatment of chronic diseases. Chronic diseases are conditions and illnesses that occur or develop over a relatively long period of time (months to years), are prolonged, and may be preventable, but are rarely completely cured. Examples of chronic diseases are diabetes mellitus (types 1 and 2), cancer, heart disease, pulmonary disease, and osteoporosis.

Sometimes it is helpful to differentiate chronic diseases (sometimes called noncommunicable diseases) from infectious diseases. Infectious diseases are illnesses or conditions that are

caused by pathogens such as viruses, bacteria, and fungi. Most infectious diseases can be treated, cured, or controlled with medicines, vaccines, or other measures such as quarantine. Infectious diseases include influenza, tuberculosis, measles, and malaria.

Many countries have improved their public health infrastructures to control the causes of infectious diseases, so chronic diseases have become an increasingly significant part of the health burden. In fact, chronic diseases such as cardiovascular diseases (i.e., diseases of the heart and blood vessels), diabetes mellitus, and some cancers present the most urgent threat to public health in developed countries. At the beginning of the 20th century, the three leading causes of death in the United States were infectious in their origins. That has given way to the current situation where the three leading causes of death are all chronic diseases, each with a high degree of association with physical activity. The 10 leading causes of death in 1900 and 2015 are listed in table 3.1.

The most important and powerful health benefits of physical activity are the prevention and treatment of chronic diseases. Through a variety of physiological processes, physically active people are much healthier and much less likely to develop and die from chronic diseases than those who are not physically active. Moreover, physical activity and exercise reduce the risk of dying prematurely (all-cause mortality). You will learn more about these health benefits throughout part II.

Table 3.1   Ten Leading Causes of Death in the United States: 1900 and 2015

Rank 1900 2015

1 Pneumonia (all forms) and influenza Heart disease

2 Tuberculosis (all forms) Cancer

3 Diarrhea, enteritis, and ulceration of the intestines

Chronic lower respiratory diseases

4 Diseases of the heart Accidents (unintentional injuries)

5 Intracranial lesions of vascular origin

Stroke (cerebrovascular disease)

6 Nephritis (all forms) Alzheimer’s disease

7 All accidents Diabetes mellitus

8 Cancer and other malignant tumors Influenza and pneumonia

9 Senility Nephritis, nephrotic syndrome, and nephrosis

10 Diphtheria Intentional self-harm (suicide)

Adapted from Center for Disease Control and Prevention. Available: www. cdc.gov/nchs/FASTATS/lcod.htm and www.cdc.gov/nchs/data/dvs/lead1900_98.pdf.

FROM SCIENCE TO PRACTICE AND BACK Public health is characterized by science and action. Epidemiology provides the fundamental science. The action aspect is the implementation of findings from scientific studies to improve health, which is what differentiates the field of public health from other basic science and biomedical science disciplines. Public health applies science to practice by addressing three critical areas: surveillance, community interventions, and the development of health guidelines.

SURVEILLANCE Public health surveillance has been defined as the ongoing, systematic collection, analysis, and interpretation of data (e.g., regarding agent or hazard, risk factor, exposure, or health event) essential to the planning, implementation, and evaluation of public health practice (Thacker 1988). Surveillance is a critical public health function because it helps us understand the extent of a health

problem and identify the types of people and populations that may be at higher risk of that health problem. The number of weekly cases of influenza, the annual death rate due to malaria, the number of heart attacks among older African American adults, and the percentage of high school students who take daily physical education classes are all real-life examples of surveillance data that are routinely collected by public health professionals.

The CDC has developed a variety of surveillance systems to monitor the health of the U.S. population. More information on surveillance for physical activity and public health can be found in chapter 4.

COMMUNITY INTERVENTIONS Interventions—preferably at the community level—are another cornerstone of public health. The science behind interventions is established during projects called efficacy trials. Efficacy trials are studies that are used to establish that a certain intervention or public health program can change a certain condition. For example, efficacy trials have been used in small interventions to test the process of supplementing a person’s diet with iron to cure iron- deficiency anemia, a dangerous condition in which the body does not have enough red blood cells to carry oxygen. A study could be designed that randomly assigns infants that have low levels of iron in their blood to two different conditions: In one condition iron would be given to the mother in the form of a pill (and be delivered to the infant through breast-feeding), and in the other condition iron would be delivered directly to the infant in an infant formula drink. The study would evaluate which of the two methods works better at increasing stores of iron in the bodies of infants.

Effectiveness studies are the other main type of intervention study of interest in public health. In effectiveness studies, the main outcome of interest relates to how well a treatment works in practice —or more appropriately, in real life instead of in controlled settings. If we consider the preceding iron-deficiency anemia situation, the

appropriate effectiveness question becomes: How well does the iron supplementation delivery method work in a community or village in which malnutrition is rampant? Obviously, many questions arise in this kind of study. For example, even if we know that the breast- feeding method appeared to work better in the efficacy study, it may not be particularly effective in a certain area because of cultural or social restrictions on breast-feeding. This presents a clear dilemma for a public health intervention—efficacy data show one route to go, but the real-life (effectiveness) evaluation of the intervention suggests something different. This situation requires additional study and observation to refine the methods to ensure the effectiveness of the intervention.

Similar challenges become apparent in the world of physical activity and public health. From exercise physiology, we know the physiological effects of a prescribed dose of exercise on physiological parameters such as cardiorespiratory fitness, blood pressure, adverse lipid and lipoprotein levels, body weight, and blood glucose response. These results come from carefully controlled laboratory efficacy trials in which the dose of exercise is managed tightly and measured very closely. Exercise has a known efficacy for improving many parameters that are related to poor health in the human body. The effectiveness of such interventions in real life becomes much more difficult and challenging to measure and assess when these studies are taken out of the laboratory and into the community. How do we translate laboratory-based studies into community interventions that will help people increase their physical activity levels and thus become healthier? This practice aspect of public health is the main focus of the third part of this textbook.

DEVELOPMENT OF HEALTH GUIDELINES The development of health guidelines is a third critical function of public health science. Public health guidelines are official policy statements, usually developed by a government body, agency, or

other reputable organization, that are based on the best available science. Public health guidelines provide clear recommendations about a course of action to deal with a pressing public health issue. Recommendations for childhood immunization schedules (when and which vaccines and their timing), diabetes treatment (the frequency and method of glucose self-monitoring), nutrient intake (micronutrient daily recommended intakes for health), and annual influenza vaccinations (type and timing) are all examples of public health guidelines that, based on the best available science, give health professionals and the public clear guidance about the most appropriate courses of action for preventing and treating certain health problems.

In 2008, the U.S. Department of Health and Human Services published the first Physical Activity Guidelines for Americans (USDHHS 2008; see the highlight box 2018 Physical Activity Guidelines for Americans). These guidelines, updated in 2018, are based on comprehensive scientific summaries to detail the best science-based recommendation for the weekly amount of physical activity necessary to prevent disease and promote positive health outcomes (USDHHS 2018). The physical activity guidelines were developed for children and adolescents, adults, and older adults. These guidelines should be used as targets for physical activity participation.

Several other countries, as well as the World Health Organization, have published guidelines similar to the Physical Activity Guidelines for Americans. Japan, Canada, Australia, and England have all taken leadership roles in establishing physical activity as a public health priority by setting physical activity guidelines and recommendations.

2018 PHYSICAL ACTIVITY GUIDELINES FOR AMERICANS Children (Aged 3 to 5 years)

Preschool-aged children should be active throughout

the day to enhance growth and development. Children

this age should be encouraged into active play for at

least 3 hours per day.

Children and Adolescents (Aged 6 to 17 years)

Children and adolescents should do 1 hour (60 min) or

more of physical activity every day.

Most of the 1 hour or more per day should be either

moderate- or vigorous-intensity aerobic physical

activity.

As part of their daily physical activity, children

and adolescents should do vigorous-intensity activity

at least 3 days per week. They also should do muscle-

strengthening and bone-strengthening activity at

least 3 days per week.

Adults (Aged 18 to 64)

Adults should do 2 hours and 30 minutes per week of

moderate-intensity, or 1 hour and 15 minutes (75

minutes) per week of vigorous-intensity aerobic

physical activity, or an equivalent combination of

moderate- and vigorous-intensity aerobic physical

activity. Aerobic activity should be performed in

episodes of at least 10 minutes, preferably spread

throughout the week.

Additional health benefits are provided by increasing

to 5 hours (300 minutes) per week of moderate-

intensity aerobic physical activity, or 2 hours and

30 minutes per week of vigorous-intensity physical

activity, or an equivalent combination of both.

Adults should also do muscle-strengthening activities

that involve all major muscle groups performed on two

or more days per week.

Older Adults (Aged 65 and Older)

Older adults should follow the adult guidelines. If

this is not possible due to limiting chronic

conditions, older adults should be as physically

active as their abilities allow.

It is important for older adults to avoid inactivity.

Older adults should do exercises that maintain or

improve balance if they are at risk of falling. For all individuals, some activity is better than none

and everyone should move more and sit less. Physical activity is safe for almost everyone, and the health benefits of physical activity far outweigh the risks. People without diagnosed chronic conditions (e.g., who do not have conditions such as diabetes, heart disease, or osteoarthritis) and who do not have symptoms (e.g., chest pain or pressure, dizziness, or joint pain) do not need to consult with a health care provider about physical activity.

PROMOTING PHYSICAL ACTIVITY FOR HEALTH As the field of physical activity and public health has emerged, it has become clear that many factors at many levels influence physical activity behaviors. Many investigators have used the social ecological model as a guiding framework to explain these multiple levels. They are illustrated in figure 3.6 and form the basis for the third section of this textbook.

At the center of the target in the social ecological model for physical activity behaviors are individual factors. These are the factors that are innate to each person and that differ among people. A person’s genetic makeup, early life experiences (e.g., youth sport participation), self-efficacy, and other factors, such as sex, disability, growth and development, and socioeconomic status, may all be important determinants of health behaviors such as physical activity.

Figure 3.6   Multiple levels of influence on physical activity behaviors: The social ecological model.

Moving out from the center, social influences on physical activity are important. Research has now shown that individual factors are not enough to explain physical activity behavior. Determinants at the social influences level aren’t characteristics of the person per se, but are, rather, characteristics of how the person interacts with society or culture. Influences at this level can include peers, medical care organizations (doctors), family members, and organizations (schools, places of worship, worksites).

The third level in the social ecological model represents environmental influences. These influences may enhance or restrict physical activity behaviors, and are external to the person but common across societies and cultures. Research on the effects of physical environment on physical activity participation has exploded as the field of physical activity and public health has emerged. The ability to influence the physical activity of vast numbers of people (instead of one person at a time) by making a single change makes environmental influences on physical activity a particularly interesting area of research. The availability of places to be active, such as trails, sidewalks, fitness facilities, bicycle lanes, community and

neighborhood design elements are examples of how the built environment can influence physical activity.

Finally, the outer level represents policy influences on physical activity. Influences in this sphere include written or unwritten rules, codes, and norms that influence environmental or social determinants of physical activity. As with the physical environment, determinants at this level are particularly attractive because of their potential to influence many people. Examples of policy influences on physical activity include policies allowing increased access to places to be physically active (making it easier to be physically active), educational policies (e.g., mandating high-quality daily physical education for schoolchildren), and transportation-related policies (e.g., making it easier to walk or bicycle for transportation).

By combining knowledge, skills, and abilities related to the basic exercise sciences and public health, you can better explain and discuss professionally the health benefits and risks of exercise and physical activity to your peers, colleagues, and the communities you serve (see part II, chapters 5 through 10). An understanding of the specific challenges that affect physical activity and exercise in professional exercise science jobs can clarify how the exercise sciences affect public health, and vice versa. The highlight box Careers Combining Exercise Science and Public Health lists careers in exercise physiology, biomechanics, and sport and exercise psychology that are commonly seen in the professional areas of health and fitness, preventive medicine, athletic performance, and rehabilitation.

PRACTITIONERS OF PHYSICAL ACTIVITY IN PUBLIC HEALTH Physical activity and public health is an emerging discipline with many opportunities. People with training in this area, particularly at the master’s level, are employed in state and local health departments working on public health programming for physical activity promotion. Many universities have research opportunities for people interested in studying physical activity and public health.

Finally, private foundations and nongovernmental organizations are interested in people with training and interests in physical activity and public health.

LEADER PROFILE I-Min Lee, MBBS, MPH, ScD

Why and how did you get into the field of Physical Activity and Public Health? I was trained as a physician and an epidemiologist. Early in my career, I primarily focused on epidemiologic investigations of risk factors for cancer, in particular, physical inactivity and adiposity. My research interest was more narrowly targeted— concentrating on identifying preventive/risk factors— rather than a more broad application to public health.

With the publication of the 1995 physical activity recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine, and the 1996 surgeon general’s report on physical activity and health, I realized that while risk factor identification is crucial, the knowledge just “sits” unless it is translated into a method in which it can be applied. For example, in my specific area of interest, the practical questions—what types of physical activity, what intensity, how much, and how often—need clarification to be useful for public health translation.

Did any one person have a major influence on your career? How? Without question, the late Professor Ralph S. Paffenbarger, Jr.—one of the pioneers in the field of physical activity epidemiology—was single-handedly responsible for guiding me into this field of research. I was working as a postdoctoral fellow on a research study of mycosis fungoides (a type of cancer), when I met Paff, as everyone called him. He invited me to work on his long- standing cohort study of physical activity and health among college alumni. I really wasn’t interested at all, since I did not have any background in this area, plus I was physically inactive! But Paff was very persistent, and I eventually agreed. With Paff as my advisor, I then went on to complete a doctoral degree in epidemiology, using his data for my thesis. I do realize how lucky I was that Paff dropped into my life; he was a truly knowledgeable and generous mentor. He pushed me into writing and speaking engagements that advanced my career, and was very generous in sharing credit with me. I have no doubt that Paff is responsible for where I am today.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My current interest is investigating the dose of physical activity (and sedentary behavior) needed for health in order to inform public health recommendations. While we do have guidelines (the most current U.S. recommendations

being the federal Physical Activity Guidelines for Americans, 2nd ed.), the scientific basis for existing guidelines is largely derived from studies using self- reports of physical activity. It has become increasingly feasible to use devices in large-scale research studies for measuring physical activity and sedentary behavior. The ability to use devices is an exciting development in the field of physical activity research, yielding large volumes of data to address detailed questions related to types, intensity, duration, frequency, and patterns of physical activity that are healthful, and informing public health and clinical guidelines.

Why do you do what you do?

In addition to finding the methodological approaches for using device-collected data challenging and very interesting, physical activity has the potential to benefit the health of large numbers of people throughout the world. Insufficient physical activity (i.e., not meeting guideline levels) has been estimated to cause more than 5 million deaths worldwide each year (Lee et al. 2012)—a number equivalent to that caused by smoking. A recent publication (Guthold et al. 2018) emphasizes this continuing public health problem, noting a high prevalence of insufficient physical activity worldwide at 27.5%; this figure was highest in affluent countries such as the United States.

What are two key issues that must be addressed by 2030? There are many public health issues that we face today. One urgent issue that comes to mind is addressing climate change: Global warming could cause parts of the world, particularly low- and middle-income countries, to become too hot for people to be physically active comfortably, potentially leading to even less physical activity. A second issue is a need for government commitment to support population-based, multi-sectoral and multi- disciplinary policies to increase the activity levels—and hence, health—of their populations.

CAREERS COMBINING EXERCISE SCIENCE AND PUBLIC HEALTH

Physical education teacher

Physical activity specialist

Firefighter

Police or military

Personal trainer

Physician

Nurse

Researcher

Movement specialist

Wellness coach

Clinical exercise physiologist

Translational exercise physiologist

Coach

Sporting goods representative

Biomechanist

Sport physiologist

Health or fitness facility owner

Physical therapist

Cardiac rehabilitation specialist

Occupational therapist

Diabetes or obesity prevention specialist

Athletic trainer

Consultant

Translational biomechanist

In 2006, a new professional organization was created in the United States. The National Society of Physical Activity Practitioners in Public Health (NSPAPPH) is now called the National Physical Activity Society (NPAS). The NPAS is a dedicated group of professionals interested in advancing the capacity of professionals in physical activity and public health in the United States. The group has taken a major leadership role in developing a definition of what it means to be a professional in the field of physical activity and public health and what core competencies are necessary for leadership in community-level interventions to promote and evaluate the effectiveness of those interventions. Many of the core competencies put forth by NPAS are addressed in this textbook and are found at the end of each chapter as a cross-reference.

NPAS has developed resources, trainings, and a certification (Physical Activity and Public Health Specialist) to create professionals in physical activity and public health. The certification is a voluntary credential that is a U.S. national standard for professionals working in this area. Important knowledge, skills, and abilities in partnership development, planning and evaluation, exercise science, development of effective interventions, and evaluation of scientific data are part of NPAS’ training and certification procedure. Knowledge and skills in each of these areas are critical for advancing physical activity and public health and developing a successful career in the field.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Physical activity and public health is an emerging discipline that combines science and practice from the exercise science disciplines and from public health and epidemiology. Physical activity, exercise, and physical fitness are three concepts that are relevant to physical activity and public health. Surveillance, community interventions, and the development of health guidelines are three key pillars of public health. The Physical Activity Guidelines for Americans are science- based summaries of the amounts and types of physical activity that produce health benefits for all ages. All humans should move more and sit less. A variety of careers are available to people with an interest and training in physical activity and public health.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Guthold R, Stevens GA, Riley LM, Bull FC. 2018. Worldwide

trends in insufficient physical activity from 2001 to 2016: A pooled analysis of 358 population-based surveys with 1·9 million participants. Lancet Global Health 6: 1077-1086.

Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT, Lancet Physical Activity Series Working Group. 2012. Effect of physical inactivity on major non-communicable diseases worldwide: An analysis of burden of disease and life expectancy. Lancet 380: 219-229.

Morris JN, Heady JA, Raffle PAB, Roberts CG, Parks JW. 1953. Coronary heart disease and physical activity of work. Lancet 262: 1053-1108.

Thacker SB, Berkelman RL. 1988. Public health surveillance in the United States. Epidemiology Review 10: 164-190.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.4.1, 2.1.1, 2.1.3, 2.2.1, 2.2.2, 2.2.3, 4.5.1, 4.5.2, 4.5.3, 4.5.4, 5.1.1, 5.1.2, 5.4, 5.4.1

CHAPTER 4 Measuring Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  Techniques to measure physical activity among individuals and populations

»  The strengths and weaknesses of these techniques »  Fundamentals of physical activity surveillance »  Sources of public health information on physical activity

OPENING QUESTIONS

»  What are the best ways to measure physical activity in individuals and in populations?

»  Can people accurately remember their physical activity patterns for weeks or months?

»  How useful are new technologies to help us measure physical activity?

As you learned in chapter 2, physical activity is any skeletal movement that results in energy expenditure; therefore, physical activity per se is a behavior (i.e., the act of moving), and energy expenditure is the direct result that physical activity has on our bodies. The most accurate techniques to measure physical activity are those that involve quantifying the amount of energy expenditure that results from being physically active. Energy expenditure can be quantified in units called kilocalories, which are often referred to as just calories. Anytime you move your body—from getting out of bed in the morning, to walking to the bus stop, to playing basketball, to walking down the hallway—you are being physically active and therefore burning calories.

You also previously learned about the different intensities of physical activity. Physical activities of moderate or vigorous intensity are most beneficial to health. When considering ways to measure physical activity, keep in mind that people can be moderately or vigorously active within different domains—that is, they can engage in physical activity for different reasons such as during one’s free time (also known as discretionary, recreational, or leisure-time domain), by walking or biking to get to and from places (transportation domain), as part of one’s job (occupational domain), or by doing activities like heavy yard work or cleaning at home (household domain). Although the term exercise is often used interchangeably with physical activity, exercise is a subset of physical activity, and falls under the domain of leisure-time physical activity. Exercise is planned, structured, repetitive, and designed to

increase or maintain physical fitness. Taking a 30-minute walk, jogging, playing basketball or tennis, and hiking and mountain climbing are all examples of exercise, since they are planned, structured, repetitive, and, most critically, they all help increase or maintain physical fitness.

As highlighted in chapter 2, physical activity and physical fitness are unique constructs. Physical activity is a behavior, and physical fitness is a physiological state. Because exercise is a subset of physical activity, it is also a behavior. Although this chapter focuses on the measurement of physical activity, there are also a wide variety of fitness assessment and measurement strategies and tests. These tests have been developed following years of research about the human body’s adaptation to regular physical activity.

Understanding measurement and assessment techniques for physical activity and physical fitness, assessing the strengths and weaknesses of these techniques, and knowing how and with whom to use them is critical for understanding and conducting studies of physical activity and health. This understanding is also important when developing, implementing, and evaluating programs for increasing physical activity in individuals and populations. This chapter gives an overview of current techniques in this area.

EVIDENCE-BASED RECOMMENDED LEVELS OF PHYSICAL ACTIVITY FOR HEALTH We know that physical activity is good. Since the early studies in the 1950s and 1960s, we have learned more about the importance of the intensity, frequency, and duration—as well as the total volume— of physical activity as they relate to health. This new knowledge has its roots in exercise science and exercise training studies. Today, we know that being routinely active has substantial benefits for cardiovascular and metabolic health, cancer prevention, mental health, sleep quality, physical function, and quality of life.

The best science-based guidelines state that adults should accumulate at least 150 minutes per week of moderate-intensity

physical activity, or at least 75 minutes per week of vigorous-intensity physical activity, or some equivalent combination of intensities (U.S. Department of Health and Human Services [USDHHS] 2018). Adults should also engage in moderate- or high-intensity muscle- strengthening activities that involve all major muscle groups on two or more days a week. Additionally, children need at least 60 minutes of moderate-intensity physical activity each day. Finally, we now know that for people not currently meeting the minimum guidelines for physical activity for their age group, substituting moderate- or even light-intensity physical activity for sedentary time can result in important health benefits.

With these guidelines in mind, we consider these questions: What are the best ways to measure physical activity? How well do these techniques measure what we want them to measure? Are they repeatable? What is needed to measure physical activity most accurately among individuals (as opposed to populations)? What methods should we use in controlled laboratory settings, and which are best for free-living individuals or populations?

LABORATORY MEASURES OF ENERGY EXPENDITURE Laboratory-based techniques that measure physical activity are based largely on the desire to assess caloric expenditure, or the amount of energy a person burns while being physically active, breathing, circulating blood, and digesting food. Total energy expenditure (TEE) is the sum of all of these components. Physical activity energy expenditure (PAEE) is the energy expenditure that is specifically the result of physical activity. The thermic effect of food (TEF) is the amount of energy that is used to digest and metabolize energy that is ingested (food and drink). Finally, basal metabolic energy expenditure (BMEE) is the energy expended to maintain breathing and circulation at rest.

Roughly 60 to 70% of a person’s TEE is composed of BMEE. Approximately 10% of TEE is used to digest food. The remaining expenditure (20 to 30%) is for physical activity. Obviously, people

who are more active and those who exercise use a higher proportion of their TEE for physical activity than people who are largely sedentary throughout the day. Because PAEE is the only component of TEE that is very changeable, we need to know how to measure that 20 to 30% very well. See figure 4.1 for more details about the determinants of TEE.

Figure 4.1   Total energy expenditure = basal metabolic energy expenditure + physical activity energy expenditure + thermic effect of food.

INDIRECT CALORIMETRY

In the laboratory, the process of measuring the components of energy expenditure is fairly straightforward. Indirect calorimetry is the technique that is used most often. With indirect calorimetry, the amount of oxygen used and carbon dioxide expelled is used to estimate energy expenditure. This can be done using a facemask and gas analysis system. Another method is when a person lives in a controlled room or setting for a period of time. Energy expenditure is assessed from air samples that are collected while the person is in the room. Calibrated gas collection devices are used to measure and analyze oxygen and carbon dioxide changes in the room.

Because carbon dioxide is a by-product of energy metabolism, it is a very good indicator of total energy expenditure in this controlled setting. Someone who burns more energy in this setting (e.g., through exercise) is easily differentiated from someone who is sedentary and not burning any additional calories. By having the subject keep a diary, or by having study personnel observe the subject, investigators can quantify the amount (frequency, intensity, and duration) and type of physical activity performed during an indirect calorimetry study. Thus, PAEE can be measured as well. This, coupled with careful measurements of the food eaten and waste produced, can give a very accurate measure of TEE.

Although indirect calorimetry is very accurate, it has limitations. First, it is relatively expensive. A special room must be built, gas analyzers must be installed, and study personnel must be hired to maintain the facility, among other costs. Second, only one person in a room (two if there are two rooms) can be measured at a time. This makes larger studies more tedious to conduct and quite lengthy to carry out. Another limitation is that the equipment needed to do these analyses can break down and usually must be calibrated frequently so that the investigator has confidence in the measurements. A final limitation is that this type of protocol does not capture TEE or its components in real life. That is, the artificial laboratory settings do not allow people to live as they would normally. This is of obvious importance in the public health world.

DOUBLY LABELED WATER A second laboratory technique that has been shown to be very accurate in measuring TEE is the doubly labeled water technique. This technique uses the principles of indirect calorimetry by measuring the turnover rates of oxygen and hydrogen: The higher the TEE, the higher the turnover rates (because of higher metabolic activity).

Doubly labeled water study participants are given a prespecified dose of stable radioisotope-labeled water. After taking some baseline measurements, investigators measure the excretion of the isotopes over the course of one to three weeks (depending on the study question and protocol) in collected urine samples. The difference in elimination rates between the labeled oxygen and hydrogen is used to estimate carbon dioxide production, which, as in indirect calorimetry, can be used to estimate TEE.

Doubly labeled water is a very safe procedure that allows people to live their lives normally (i.e., they are not confined to a calorimetry room), and has been shown to be very precise. Participants must collect and store urine samples frequently, which can be a burden, and the radiolabeled hydrogen and oxygen are fairly expensive ($280 to $800 in USD in 2018). Moreover, substantial equipment (a mass spectrometer) and assay tools are needed for analyzing the samples. Another important limitation is that the assay allows only the estimation of TEE. Estimation of PAEE is unattainable using the doubly labeled water method unless the investigator also has a measure of BMEE from indirect calorimetry (remember that TEE = BMEE + PAEE + TEF). This can be a significant limitation if assessment of PAEE is the desired outcome. Further, the method tells us nothing (alone) about how or why the physical activity was performed (e.g., walking for recreation or walking for transportation). This type of information (i.e., domains of physical activity) is usually helpful if understanding why people are active or inactive, or changing physical activity behaviors is of interest.

ELECTRONIC DEVICES TO MEASURE PHYSICAL ACTIVITY Early studies in the field have relied on self-report instruments to assess physical activity. We will learn more about self-report measures further along in this chapter. Advances in technology, however, have resulted in the development of devices that can objectively measure movement (see figure 4.2).

Figure 4.2   Wearable devices that capture movement and acceleration have greatly increased the ability to measure human physical activity.

ACCELEROMETERS Accelerometers are small piezoelectric devices that measure the magnitude and direction of acceleration. Accelerometers of many varieties are used for applications as varied as oil and gas drilling, navigation, and transportation. For human movement and physical activity, accelerometers have proven very useful in determining total physical activity and in estimating energy expenditure. However, although accelerometers have advanced our ability to measure physical activity, they provide no information regarding the type of activity being performed. For example, a period of brisk walking is indistinguishable from a tennis match to an accelerometer.

Accelerometers measure movement and physical activity by measuring acceleration forces in one, two, or three planes (or axes)

as a result of a change in the velocity of the body. Semiconductors translate the processing of movement to acceleration. The following simple equation shows the mathematical relationship between acceleration (a), change in velocity (Δv), and change in time (Δt). As velocity increases for a given time, so does acceleration. When the amount of time decreases (at a constant velocity), acceleration also increases.

a = Δv / Δt Using this relationship, an accelerometer worn against a person’s

body measures changes in velocity and time. Accelerometers record these measures as counts—numerical values given to the acceleration recorded at a given point in time. Counts alone are not very meaningful, because the scale is an arbitrary one that varies depending on the make and model of the accelerometer. Modern- day research-grade accelerometers record between 30 and 120 data points (counts) per second. The number of counts collected per second by the accelerometer is referred to as the sampling rate. Because such sampling rates produce a very large amount of information, researchers usually export the data by aggregating them to the 1-second, 10-second, 30-second, or 60-second level. This aggregated time segment is known as an epoch. For instance, if an accelerometer uses a sampling rate of 30 counts per second, and we use a 60-second epoch to summarize the data, each data point (cell) in our accelerometer dataset would represent the average value of 1,800 counts (30 counts per second × 60 seconds in the epoch). Counts per epoch can then be converted into estimates of energy expenditure. Several researchers have conducted laboratory- based studies employing different models and brands of research- grade accelerometers to develop specific energy expenditure formulas. Most accelerometer energy expenditure formulas are based on counts per minutes; that is, they assume a 60-second epoch. These formulas are useful because they provide cut points for different intensities of physical activity. These cut points tell us the

minimum number of counts per minute that need to be recorded by an accelerometer to indicate light-, moderate-, or vigorous-intensity physical activity. Something critical to keep in mind when using accelerometers is that physical activity intensity cut points are age- and brand-specific. One must become familiar with all the models, brands, and energy expenditure formulas (cut points) available before collecting and processing accelerometer data in a given study.

Accelerometers are very useful for measuring physical activity because they take human recall out of the equation. Participants can attach an accelerometer unit to a waistband and forget it throughout the course of the day—they are free to go about their usual activities of daily living without having to remember anything. In addition to estimating time spent at specific intensities of physical activity, accelerometers can also determine time spent in continuous periods of physical activity above a certain time threshold (e.g., 10-minute bouts). Continued technological advances allow for multiday data storage (sometimes more than 20 days) for long-term behavior monitoring.

Accelerometers can be relatively expensive (the better ones exceeded $225 USD in 2018) and may not be accurate for all kinds of activities. Most accelerometers are not waterproof; thus, they cannot be used to measure physical activity in the pool, ocean, or anywhere it is wet. Most accelerometers accurately record physical activity levels when worn on the waist, making them an inadequate instrument for measuring bicycling activity. Because downloading, processing, and analyzing accelerometer data is a complex task requiring high-level training, accelerometers are best suited for rigorous research studies.

Figure 4.3   GPS monitor.

GEOGRAPHIC POSITIONING SYSTEMS (GPS) MONITORS In recent years, investigators have started to use wearable GPS monitors to measure and characterize physical activity spatial patterns. Research-grade GPS devices collect accurate geographic location data every 5 to 60 seconds. These instances, referred to as waypoints, represent each geolocation where a participant is detected via satellite systems every x seconds. In addition to recording locational characteristics (latitude and longitude), each waypoint contains additional critical information: a date stamp, a time stamp, and a measure of altitude. By using these variables together, we can derive the velocity at which a person is traveling in space (from waypoint A to waypoint B to waypoint C and so on). Investigators employ algorithms to categorize trips as car-based, bicycle-based, or walking based on velocity data. This travel mode detection and the total minutes per day spent in active travel are the

typical physical activity indicators that can be obtained from GPS monitors. However, a small number of researcher groups around the world have now begun to simultaneously collect GPS and accelerometer data. Using complex time-matching algorithms, the combined use of GPS and accelerometers allows investigators to map moderate- and vigorous-intensity physical activity in space (e.g., to identify the places within a city where most physical activity occurs), as well as to detect and assess duration and intensity of bicycling behaviors (which are difficult to assess with accelerometers alone).

Like accelerometers, GPS monitors remove human recall out of the equation, making them a powerful assessment tool. Also like accelerometers, GPS devices can be attached to a waistband (see figure 4.3), are relatively expensive (high-quality models exceeded $200 USD per unit in 2018), and require highly trained individuals for data download, processing, and analysis. Because of the large amount of spatial data being collected by GPS monitors, battery life continues to be a significant drawback for these instruments. Most research-grade GPS devices have to be recharged by the participant nightly to ensure sufficient battery life for another full day of data collection. It is expected that with time these technologies will improve, allowing for longer battery lives and continuous days or weeks of data collection. One limitation of GPS monitors, when used alone (as opposed to simultaneously with accelerometers) is that they only capture physical activity with spatial displacements (moving from point A to point B in space). GPS monitors alone would not be useful to assess physical activity occurring in a static point in space (e.g., treadmill running). Ethical concerns related to participants’ privacy are also a consideration when dealing with GPS monitors for physical activity assessment. Some people are hesitant to participate in studies that will collect continuous data on their whereabouts. Rigorous protocols that protect participants’ right to privacy, and that safeguard their geolocational data, must be

followed and further enhanced as these instruments become increasingly popular for physical activity research.

PEDOMETERS Pedometers (or step counters) are another kind of electronic monitoring device that can be used to take the recall bias out of physical activity assessment. They are usually most useful for measuring walking, running or jogging, or any other type of physical activity that involves the lower body. Many kinds of pedometers exist, using several types of mechanisms, although they all fundamentally measure total steps (see figure 4.4). Some rely on a spring or a spring lever to record the movement, others use a strain gauge, and still others use a magnetic switch.

Figure 4.4   A pedometer is an inexpensive and easy way to track the number of steps taken over a period of time. It can also be a useful reminder, and can help people set goals for steps per day.

A key strength of pedometers is that they are fairly inexpensive and thus can be used by many people (good pedometers could be purchased for $15 to $40 USD in 2018). They are fairly simple and straightforward to use and seem to accurately measure the number of steps taken. Studies have shown a range of accuracies among various brands, with the less expensive pedometers generally being less accurate than more expensive ones. Pedometers help people become more active by reporting the total number of steps they have

taken (e.g., toward a preset goal), thereby reminding them to be active.

When collecting pedometer-based physical activity data, the least common denominator is steps taken during the observation period. With additional data collection, such as a diary or questionnaire, or with better pedometer models, one can obtain information on steps taken per day or steps within different periods of the day, weekdays versus weekends, and so on. A substantial drawback to using pedometers for measuring physical activity is that they do not directly measure velocity or time and thus cannot estimate acceleration. This means that time spent in different intensities of physical activity cannot be derived simply by having information on total steps taken over a period of time. A pedometer weights each recorded step with the same value, whether that step was taken while strolling slowly, during a sprint run, or during a soccer game. Clearly, the dose of physical activity differs in these various situations, but a pedometer would not be able to determine that without additional data collection.

CONSUMER-BASED WEARABLE TRACKING DEVICES AND APPS Most people in high- and middle-income countries, and a substantial proportion of people in low-income countries, now carry smartphones. In recent years, there has been a rapid surge in the availability of smartphone applications (apps) for health-monitoring purposes. This includes apps to monitor one’s physical activity levels. While many apps simply offer monitoring services, others also include interactive features such as competition with other app users, or goal-setting, to help the user achieve a better health status. In addition to smartphone apps, many people also own wearable wristband monitors (e.g., Fitbit) that link to one’s smartphone via Wi- Fi or Bluetooth, and that track physical activity patterns throughout the day. These apps and tracking devices rely on technologies similar to those previously described, including built-in pedometers and GPS receivers. However, the technology in these consumer-

based products is usually not as advanced as those found in research-grade devices, and the algorithms used to derive acceleration and velocity, and thus energy expenditure, are mostly unknown because these are proprietary products.

While some research has emerged in an attempt to determine if these new technologies are good at accurately measuring physical activity in individuals and populations, to date, these consumer- based tracking devices are not considered ideal for measurement purposes in research. Some of their limitations include unstandardized wearing positions (some people carry their smartphone in their pocket, others put it in a backpack or purse), low validity when compared to research-grade accelerometers, and high potential for reactivity due to the readily available information about the user’s activity patterns. Reactivity is the tendency to modify one’s habitual behavior after becoming aware of being measured or observed. The phenomenon of reactivity can be very difficult to control in studies of physical activity behavior, but it becomes particularly problematic when participants have direct and real-time access to the results of the measures being performed, as is the case with consumer-based tracking devices and apps.

DIRECT OBSERVATION TECHNIQUES A popular way to measure physical activity behavior is the direct observation of people using certain places of interest. Using trained observers, researchers can get a standardized view of physical activity participation and intensity for groups of people (e.g., the amount of time children are inactive during a physical education class). These observers, who are trained to recognize certain characteristics of physical activity such as intensity level, record what they see during a period of time. These observations can then be converted to estimates of group-based energy expenditure based on the proportion of participating group members, and the distribution of intensity, frequency, and duration of the physical activity or exercise observed. Direct observation techniques are the only available direct

measure of physical activity behavior and are considered an objective measure of physical activity behaviors when properly implemented.

SOFIT AND SOPARC SOFIT (system for observing fitness instruction time) and SOPARC (system for observing play and recreation in communities) are two excellent examples of direct observation techniques to assess physical activity among children and adolescents in defined areas. Both measures, developed at San Diego State University by Dr. Thom McKenzie and colleagues, have helped us get objective measures of physical activity in youth. SOFIT is used to assess the amount of physical activity occurring during physical education classes, or during any physical activity class setting (e.g., an aerobics or yoga class). SOFIT provides important information about the quality of the physical activity class by measuring not only the amount of physical activity the students are engaging in during class, but also the quality of specific class activities and behaviors of the instructor. SOPARC is used to measure physical activity and associated environmental characteristics in park and recreational settings. More information on these two techniques can be found at www.activelivingresearch.org.

Direct observation techniques can be very useful in many situations. They are particularly helpful in identifying how people use defined spaces (e.g., parks, playgrounds, bike lanes, sidewalks, and neighborhoods) for physical activity. Direct observation techniques, however, do have drawbacks. First, they can be relatively expensive, given the cost of training and employing observers. However, in certain parts of the world where labor costs are low, or volunteers are readily available, these methods are quite inexpensive, making them feasible and popular, often more so than device-based measures. Second, the observer training is a very important aspect

of this technique. The investigator needs to be sure that what one observer calls moderate-intensity physical activity is the same as what the other observers are identifying as such. Further, that definition cannot drift over time—that is, an exercise that is classified as vigorous intensity should be classified as such throughout the study. Direct observation techniques are not feasible when assessing physical activity occurring throughout various settings (e.g., measuring participant activity both within a city and in a specific park). Studies using direct observation methods must have a clear focus on the setting where the assessments will take place rather than on the individuals. For example, an organization may be interested in diagnosing and improving the levels of physical activity occurring in public recreation centers in low-income neighborhoods; SOPARC would be an excellent tool for measuring physical activity in such a project.

Would you do things a bit differently if you knew someone were observing or recording your physical activity behavior?

Finally, people’s behaviors often change simply because they know they are being observed or measured, as with consumer- based tracking devices or apps. That is, direct observation is highly prone to participant reactivity. If you knew that your physical activity and exercise behavior were being monitored, do you think you might alter what you do and how long or how intensely you participate? Most often, investigators try to observe physical activity in public areas where observers are not identifiable. This anonymity minimizes reactivity and results in a better measure of physical activity behavior. Some investigators now use discrete webcams to record activity at certain public spaces, and they code activity levels from a computer. However, these practices are still being refined and have raised ethical questions with respect to people’s right to privacy. These important concerns should continue to be considered as this field of research and new technologies advance.

SELF-REPORT INSTRUMENTS Historically, the most frequently used techniques for physical activity assessment, particularly in studies of how physical activity and exercise influence health outcomes, have been based on self-report. Science based on self-report instruments has been able to show that physical activity greatly decreases (and physical inactivity greatly increases) a person’s risk of a variety of chronic diseases. This science has also demonstrated the dose-response effect. Higher levels of self-reported physical activity are associated with lower risk of disease outcomes. Part II of this textbook details some of this evidence.

With self-report, study participants are asked to tell the investigators, either in interviews or via questionnaires or a diary, about their participation in physical activity, usually over a defined period. This period can be short (24 hours), a bit longer (the last 7 or 30 days), or much longer (extending to the distant past). These responses are then classified across the study population, and people are categorized based on their reported physical activity.

Analysis of such data can be done in a variety of ways, but is usually set up to examine exposure to physical activity (low amount vs. high amount, or low, medium, or high). This exposure, which is meant to be an estimate of PAEE, can then be related to an outcome such as risk of heart attack or osteoporosis.

THE 7-DAY PHYSICAL ACTIVITY RECALL As with direct observation and diary techniques, physical activity interviews work best when the period of time is defined. The 7-Day Physical Activity Recall is an interviewer-administered questionnaire that has been used for many years in physical activity research (Blair et al. 1985). The participant is asked first about the most distal day (i.e., seven days ago). The interviewer asks about sleep time, sitting time, vigorous-intensity activities (e.g., jogging and cycling), and moderate- intensity activities (e.g., walking). Each activity recalled is probed for duration of participation. With the help of the interviewer, the participant reports all activities in each of these categories. Light-intensity physical activity (i.e., less than 3 METs) are inferred once the other intensities have been assessed. The interviewer then proceeds to the next day and repeats the process. The protocol continues until the most recent (proximal) day. The data are then summarized and an estimate of PAEE, as well as TEE, is calculated based on the reported activities, their duration, and their frequency. These interviews often take more than 45 minutes to complete!

DIARIES Physical activity diaries are essentially the same as any other type of diary. Study participants are asked to record their physical activities at various time points during the study. The idea is to develop a protocol that maximizes recall and minimizes error—such as asking participants to record their physical activities immediately after they

occur or at bedtime. In this way, they are less likely to forget meaningful physical activities and their intensity, frequency, and duration. Personal trainers and coaches frequently use this technique to help exercisers and athletes understand and adhere to their training regimens.

Diaries can be particularly helpful in understanding the context and type of physical activity. Walking or bicycling to school, for example, is often an important type of physical activity behavior to measure, and people—even children—can remember these events and record them in a diary. Beginning and ending times can be recorded in a diary to give the investigator an idea of the duration (and therefore the intensity). Diaries may also help investigators understand the behavior pattern (day-to-day variability) of people in a defined time period. The data gathered in physical activity diaries can be hard to summarize, however, particularly when study participants keep diaries for extended periods.

INTERVIEWS Interviews have been used to measure physical activity in a variety of settings. The person conducting the interview, after appropriate training, most often follows a predetermined interview protocol to learn details about study participants’ physical activity behaviors. Memory cues and prompts are often used to aid in accurate reporting. For example, asking a person what time she went to sleep and what time she awoke the next day provides an excellent estimate of sleep time, or energy expenditure at or near BMEE. A good interviewer can prompt the participant to provide information that otherwise may go unreported.

Interviews have several advantages. They are conducted by trained personnel who can probe for items that participants may not readily recall, which enhances the overall accuracy of the measurement. They can be structured so that the context as well as intensity, frequency, and duration of the physical activities are reported. They also are not subject to the reactivity problem because

people are asked to recall the past—and the past cannot be altered in any way that we know of!

Interviews can be expensive and have a substantial participant burden, however. Some interviews can take 30 to 45 minutes, and people sometimes struggle to remember even the broadest details about days in the past. Studies have shown that recalls of moderate- intensity activities are much more prone to reporting errors than are those of vigorous-intensity activities or rest (Pettee Gabriel et al. 2010). Finally, interviewer training (or lack of it) can be a source of substantial error. A good interviewer is essential for helping a participant remember details. A bad or inconsistent interviewer does not elicit the same response.

QUESTIONNAIRES The final self-report method for physical activity assessment is the use of questionnaires. Questionnaires can be administered directly to participants (in person or on the Internet) or over the telephone as part of a telephone survey. The difference between a self- administered questionnaire and one administered in a telephone survey or via an interview, as discussed earlier, is that the telephone survey administrator most typically follows a predetermined script. People who facilitate telephone surveys rarely, if ever, have the latitude to probe and deviate from the script.

SELF-REPORT IN CHILDREN Physical activity among children and adolescents is an important concern for health, growth, and development. Children who are inactive are more likely than their active peers to grow up to be inactive adults. Many attempts to assess physical activity in youth using questionnaires have been made over the years. Because of a child’s lack of awareness and inability to recall,

however, questionnaires generally are not recommended for children until the age of 12.

Questionnaires have evolved over the years as our understanding of the effects of physical activity on health outcomes has evolved. The earliest questionnaires asked respondents to report occupational physical activity. Job classifications and estimated energy expenditure in broad job categorizations were used to estimate PAEE. Very quickly, though, it became clear that an understanding of other domains of physical activity (including transportation, recreation, and household) were important, making an understanding of occupational physical activity less of a priority than an understanding of the full range of physical activity.

Questionnaires are usually developed to assess physical activity exposure(s) of interest. For example, participants in a study of the effectiveness of a training program could be asked about their exercise habits (i.e., frequency, intensity, and duration) before beginning the program. The data from the questionnaire would be summarized and used in planning the training protocol of interest.

The time frame of interest is usually a critical component of questionnaire assessments of physical activity. This component also presents many difficulties in comparing results across studies because many different time frames have been used, such as the following:

Past three days Past week Past 30 days A typical week A typical month

Questionnaires have also been used to quantify physical activity in the distant past. This technique is particularly appealing for studies of chronic diseases such as heart disease and cancers because it attempts to assess physical activity prior to the clinical manifestation of the disease. Because the biological influences of physical activity

on disease presumably occur over a long period of time, historical recall of physical activity can be very helpful.

DEVICES AND SELF-REPORT INSTRUMENTS: WHAT DO THEY ACTUALLY MEASURE? Devices (such as accelerometers, GPS monitors, pedometers, and consumer-based wearables and smartphone apps), measure movement. Meanwhile, self-report instruments (such as diaries, interviews, and questionnaires) measure behaviors. This is an important distinction. When a device records acceleration and derives velocity, and thus energy expenditure, it is not taking into consideration what the person wearing the monitor is actually doing. An accelerometer may record a minute spent in moderate- intensity activity, but it cannot distinguish whether that minute occurred in the middle of a walk to the bus stop or in a soccer game. If the device were replaced with an interview, for example, the person may self-report having played soccer for an hour and a half. This is the approximate duration of a soccer match, so this amount seems reasonable, and gives us no reason to assume any sort of response bias. However, if this person had worn an accelerometer during the soccer match, it is almost certain that the accelerometer would not have recorded anything close to one and a half hours of continuous moderate to vigorous physical activity. The bottom line is this: Depending on the specific behavior (walking, running, bicycling, playing a particular sport), the amount of moderate- to vigorous-intensity physical activity recorded by a device can vary greatly from the amount reported by an individual.

Questionnaires and telephone surveys are cost-effective ways of obtaining a substantial amount of physical activity and tracking data on a large group of people. Questionnaires can be mailed, sent electronically, or administered in a group format. The emergence of handheld technologies (smartphones and tablet computers) has

opened up a new set of opportunities for physical activity assessment using questionnaires and surveys. Questionnaires can be written and implemented in multiple languages and can be repeated fairly easily over the course of a study. Questionnaires can also be tailored for the specific purpose of the study and population of interest (e.g., older adults, children, cardiac rehabilitation patients).

Questionnaires for physical activity assessment do have some substantial drawbacks, however. Many of these relate to specific types of response bias, that is, when participants provide inaccurate responses to surveys. Recall bias—the inability to accurately recall, or the selective recall of only certain activities—can substantially influence respondents’ answers to questions. The inability to probe respondents for more complete answers may result in many physical activities not being reported. Social desirability bias is another type of response bias, and it refers to how people tend to respond to a question based on what they feel others expect or consider good. If you were being probed about your physical activity habits, given that you know that physical activity is good and you feel that you should be doing more of it, do you think you would be inclined to exaggerate your responses? Also, the validity of the responses is always a question. Are respondents overestimating (or underestimating) their behaviors? Despite these challenges, questionnaires have taught us a lot about the relationship between reported physical activity and health and disease.

SURVEILLANCE IN POPULATIONS Disease surveillance has been a fundamental pillar of public health at least since the era of the Black Death in Europe in the 14th century. During this time, fundamental health interventions (quarantine, determining an outbreak) were developed based on counting the number of people affected by the deadly disease. Other epidemics in subsequent centuries have led to more systematic data collection of births and deaths and the emergence of vital statistics

systems. A plague in London in the 16th century led to the development and routine dissemination of the Bills of Mortality, the first known systematic system for collecting death information. These weekly summaries were used to map and monitor the extent of the plague in the city. In the next century, John Graunt famously converted these simple counts of dead citizens to useful and interpretable surveillance techniques in his work Natural and Political Observations Made Upon the Bills of Mortality.

PUBLIC HEALTH SURVEILLANCE Public health surveillance has been defined in the modern era as the ongoing, systematic collection, analysis, and interpretation of health- related data. These data are meant to be used in the planning, implementation, and evaluation of public health practices, and their interpretation is meant to be disseminated to those responsible for prevention and control. Thus, surveillance is not merely the collection and analysis of data; it also involves action on the part of public health officials.

As population disease burdens have expanded over the years beyond infectious diseases to include noncommunicable diseases and their precursors, techniques and strategies for surveillance have evolved to address these health issues. Public health surveillance expanded from counting deaths and cases of a certain disease to monitoring those who may have been exposed to a certain disease and the trends and patterns of the disease in populations. It now also involves monitoring behavior and environmental exposures regardless of disease status and policy and environmental correlates of the risk of disease (USDHHS 2015 and 2016a). New techniques have also emerged as technology has advanced. Given this evolution and expansion of public health surveillance, Declich and Carter (1994) proposed that it emerged as a new subdiscipline separate from epidemiology.

PHYSICAL ACTIVITY SURVEILLANCE

Surveillance of physical activity is in its infancy relative to the surveillance conducted on other important public health problems. Its recent emergence is likely partially due to the fairly recent union of the fields of kinesiology and public health to create the subdiscipline of physical activity and public health (Kohl et al. 2006). It is also partially due to the recent realization that a lack of physical activity is a major determinant of multiple noncommunicable diseases. This acknowledgment of the importance of physical activity to public health has resulted in the development and evolution of surveillance techniques as our understanding of the dose and types of physical activity that promote health and prevent disease and disability becomes clearer. Also of interest are determinants—individual and environmental—that promote physical activity (Kohl and Kimsey 2009).

Different tools have been used in different countries and regions to obtain country-specific surveillance data. Although these tools have been helpful for the countries using them, the ability to compare and contrast data between countries and populations has been limited. Happily, major advances have been made toward a standardized tool for use around the world, in high-income as well as in low- and middle-income countries.

Internationally, two major developments have greatly assisted with the population surveillance of physical activity behaviors. The International Physical Activity Questionnaire (IPAQ) (Craig et al. 2003) and the Global Physical Activity Questionnaire (GPAQ) (Bull et al. 2009) represent two responses to this question: Can a physical activity surveillance system be developed to allow consistent measures, within and between countries, of physical activity participation? The IPAQ, first developed in the 1990s, was the first to allow such consistent measures across countries; it has since been used in more than 100 countries.

What proportion of adults in a population are active at recommended levels? How many report regular walking? Do these proportions vary by age, sex, or race or ethnicity? What are long-

term trends in these values over time? Is the population becoming more active? Less active? Remaining the same? These are the kinds of questions physical activity surveillance systems can answer. These data are used to inform public health professionals and others who can plan strategies to make changes to improve the health of populations. Some answers to these global physical activity questions can be found in the special Lancet Series on Physical Activity I & II, published in 2012 and 2016, respectively (Hallal et al. 2012; Sallis et al. 2016). These sets of publications, which represent the first attempt of quantifying the scope and burden of physical inactivity worldwide, concluded that physical inactivity today should be properly characterized as a pandemic (Kohl et al. 2012). Merriam- Webster Dictionary defines a pandemic as a disease or health factor “occurring over a wide geographic area and affecting an exceptionally high proportion of the population.” Findings from the 2016 Lancet series report that about one-fourth of the global population is insufficiently active, and that little change has occurred at the global scale since 2012, reaffirming the notion of a global pandemic of inactivity (Sallis et al. 2016).

POPULATION INDICATORS OF PHYSICAL ACTIVITY Surveillance data on physical activity provide a wealth of information —sometimes too much. The challenge of using these kinds of data is to find the correct indicator or indicators that best suit the purpose. Frequently used measures of interest from physical activity surveillance are those associated with health outcomes.

Most physical activity surveillance systems provide data such as the number of people in a population who participate in moderate- intensity and vigorous-intensity physical activity, the number of people who meet physical activity guidelines, the prevalence of specific physical activities such as walking, and the prevalence of sedentary behavior. Further, domain-specific surveillance becomes important for understanding the purpose for which physical activity is taking place. This helps us understand overall population-levels of

physical activity in context. For instance, two countries may have the same levels of overall physical activity with the same proportion of people meeting physical activity guidelines. However, in country A, most of the physical activity results from the transportation domain (i.e., people frequently walk or bike to get to and from places). Meanwhile, in country B, most of the physical activity comes from leisure-time physical activity (i.e., exercising and playing sports is very popular, but people do not frequently walk or bike to get to and from places). Being aware of this context is critical to understanding why some populations are very active and others are not, as well as how to come up with large-scale solutions (investments in better public transit infrastructure or in sports and exercise facilities) to promote physical activity among entire populations. The recent emergence of evidence-based physical activity guidelines has greatly helped define and standardize key outcome measures to use in physical activity surveillance systems.

Attention has recently turned to the role environment and policy indicators can play in physical activity surveillance. Characteristics of the social and built environment, as well as policies that support or inhibit physical activity, appear to be related to physical activity behavior. Policies can include anything from state laws to support the training of physical education teachers (to increase capacity for physical education) to local government actions to construct bicycle- friendly pathways that encourage active commuting. Chapter 15 contains more discussion on physical activity policies, but questions that can be asked include the following: Does access to different types of places in which to be active play a significant role? Are there measurable changes over time in the prevalence of these places? Examples of environmental indicators for leisure-time physical activity can include the location of and access to parks, trails, and other green spaces, recreation and fitness centers, and other places to be active. On the other hand, environmental indicators for transport-based physical activity could include location of and access to transit stops, or availability and quality of sidewalks and bike

lanes. Legislative policies include mandates for school-based physical education and active-school-transport programs.

SOURCES OF PHYSICAL ACTIVITY DATA In the United States, the ongoing surveillance of physical activity behaviors of adults occurs in the CDC-run National Health Interview Survey (NHIS; USDHHS 2016b) and in the Behavioral Risk Factor Surveillance System (BRFSS; USDHHS 2016a). Periodic surveys such as the National Health and Nutrition Examination Survey (NHANES; USDHHS 2017) supplement our understanding. The Youth Risk Behavior Surveillance System (YRBSS; USDHHS 2015) is used to monitor physical activity levels in high school students. No physical activity surveillance data are available for children younger than high school. Table 4.1, adapted from Carlson and colleagues (2009), highlights key data available from each of the three major sources of adult physical activity surveillance in the United States. In the United States, another new source of physical activity data is the 500 Cities Project, resulting from a joint effort between the National Institutes of Health and the Robert Wood Johnson Foundation. The 500 Cities Project database includes tabular and map data of the prevalence of physical activity participation at the city and neighborhood (census tract) levels.

Other countries also have substantial physical activity surveillance systems that address the prevalence of physical activity and inactivity in those countries. A key challenge for establishing global surveillance systems of physical activity is standardizing the data and indicators so that comparisons across countries are possible. Countries may use different instruments to collect surveillance data, although currently most use either IPAQ or GPAQ, which has facilitated international comparisons. The Lancet Series on Physical Activity and, more recently, the Global Observatory for Physical Activity (GoPA!), have led the way with the development and use of standardized indicators of physical activity to compare levels and progress across countries. GoPA! is an excellent user-friendly

resource to explore global and country-specific trends in physical activity levels, research, and policies.

Finally, although most national surveillance systems are based on self-report instruments, it is becoming increasingly common among countries, especially high-income nations, to collect robust accelerometer-based data among representative samples of residents to more objectively quantify the levels of physical activity of the country. There are at least five countries (United States, Canada, Norway, Sweden, Australia) that have collected accelerometer data among representative samples of adults at some point in time, and many are starting to do it recurrently. However, the variation found in different data collection protocols and accelerometer brands, as well as the cost associated with using these instruments in very large samples, makes the global use of accelerometers for surveillance purposes an ongoing challenge. Perhaps in the near future the emergence of new technologies and analytic methods will allow us to easily and seamlessly collect objective physical activity data from around the world.

Table 4.1   Characteristics of U.S. Physical Activity Assessments Category NHIS NHANES BRFSS

Survey years physical activity data were collecteda

1998-2016 1999-2017 2001, 2003, 2005, 2016

Recall period

Respondent selects recall period, past 12 months, past 2 weeks, past weekb

Past 30 daysc

Usual weekd Usual week and past 30 dayse

Self- reported

Yes Yes Yes

List of specific activities

Not in first years; yes in recent years

Yes No

Assesses moderate- intensity physical activity

Yes, but includes light intensity

Yes Yes

Assesses vigorous- intensity physical activity

Yes Yes Yes

Which intensity level is asked about first?

Vigorous Vigorous Moderate

Definition of moderate- intensity physical activity

Light sweating or a slight to moderate increase in breathing or heart rate

Until 2006: light sweating or a slight to moderate increase in breathing or heart rate As of 2007: small increases in breathing or heart rate

Small increases in breathing or heart rate

Definition of vigorous- intensity physical activity

Heavy sweating or large increases in breathing or heart rate

Until 2006: heavy sweating or large increases in breathing or heart rate As of 2007: large increases in

Large increases in breathing or heart rate

breathing or heart rate

Definition of active based on the Healthy People 2020 objective

At least 150 minutes of light or moderate leisure-time activity per week, 75 minutes of vigorous activity, or 150 minutes per week of an equivalent combination of activity

At least 150 minutes of moderate leisure- time activity per week, 75 minutes of vigorous activity, or 150 minutes per week of an equivalent combination of activity

At least 150 minutes of moderate leisure- time activity per week, 75 minutes of vigorous activity, or 150 minutes per week of an equivalent combination of activity

Definition of inactive based on the Healthy People 2020 objective

No reported light- to moderate- or vigorous-intensity activity for at least 10 minutes

No reported moderate- or vigorous-intensity activity for at least 10 minutes

No reported moderate- or vigorous-intensity activity for at least 10 minutes

Abbreviations: BRFSS, Behavioral Risk Factor Surveillance System; NHIS, National Health Interview Survey; NHANES, National Health and Nutrition Examination Survey. aIncludes years in which the same physical activity question was asked of respondents. NHIS asked a slightly different physical activity question in the first half of 1997, which included a minimum duration of “at least 20 minutes.” This changed midyear in 1997 to “at least 10 minutes” and has remained unchanged ever since. bIn early years, NHIS physical activity questions allowed respondents to select the recall period. To define physical activity levels, the average number of times per week (rounded to the nearest time) was calculated for those respondents who selected monthly or yearly time periods. In more recent years, questions have shifted to defined recall periods, with some questions asking about participation in physical activity over the past 12 months, the past 2 weeks, or the past week (in most recent years). cNHANES collected data on past 30 days between 1999-2006. dAs of 2007, NHANES has used GPAQ to collect physical activity data. GPAQ asks about physical activity in a “usual week” (7 days), and collects domain-specific physical activity data for the recreational, transport, and occupational domains. eBRFSS has separate sections on physical activity in a usual week, as well as about monthly participation (yes or no) in specific physical activities such as running, calisthenics, golf, gardening, or walking for exercise. The weekly module has not been included in every iteration of BRFSS. Adapted by permission from S.A. Carlson et al., “Differences in Physical Activity

Prevalence and Trends From 3 US Surveillance Systems,” Journal of Physical Activity and Health 6, Suppl 1 (2009): S18-S27.

COMBINING MEASUREMENT APPROACHES

Many ways of assessing physical activity exist, with no single assessment recommended for every situation. Large studies that follow many people for long periods in order to track health problems are likely to need self-report questionnaires to assess physical activity. Smaller studies of shorter duration that are interested in short-term behavior changes resulting from a controlled intervention may be best suited for relying on accelerometers as the primary physical activity assessment method. Characteristics of the environment and population under study all must be factored in to the decision of which physical activity assessment technique to use. Each type has strengths and weaknesses that must be thoroughly understood.

Ideally, combined approaches should be used to arrive at the most thorough estimate of physical activity. Strategies that combine self-report, direct observation, and device-based assessment techniques are becoming increasingly popular among research teams, but challenges associated with data merging and standardization remain. You should ask yourself some key questions to help select a comprehensive set of tools and instruments for your project: What is the purpose of the project? Is it surveillance? Alternatively, do you want to determine the effect of a specific intervention among a specified group of individuals? Do you care more about precision at the individual level or at the group level? Are you interested in determining total levels of physical activity, or do you want to know how much of it occurs for transportation versus recreational purposes? Are you interested in all activity, regardless of where it happens? Or, do you care about physical activity occurring in specific settings? Equally important, what resources do you have available to conduct the study (your team of investigators and data collectors, the equipment, space, and funds available)? Figure 4.5 can help you determine which types of assessment methods are best suited for your study.

Figure 4.5   Physical activity measurement instruments: balancing practicality with precision. Based on G. Welk, J. Morrow, P. Saint-Maurice, Measures Registry User Guide: Individual Physical Activity. (Washington, DC: National Collaborative on Childhood Obesity Research, 2017). http://nccor.org/tools-mruserguides/wp- content/uploads/2017/NCCOR_MR_User_Guide_Individual_PA-FINAL.pdf

LEADER PROFILE Geoffrey P. Whitfield, PhD

Why and how did you get into the field of Physical Activity and Public Health? I was a master’s-level clinical exercise physiologist working in cardiac rehabilitation. Although working with patients was rewarding, I was more interested in the research that led to our clinical approaches. I had taken a course in physical activity epidemiology as a master’s student, and kept in contact with my former professors.

During one of these conversations, I learned of a new PhD program starting in my hometown; I applied, and was accepted. It was a great fit, and very convenient for me and my family.

Did any one person have a major influence on your career? How? Perhaps the one person with the most influence, even preceding my academic advisors, was my wife, Mandy. She convinced me to take the plunge to return to graduate school, twice! She reminded me that time was going to pass whether I was in school or not, and that the benefits would outweigh the cost of staying at a job where I was not 100% satisfied. As usual, she was wise beyond her years.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? I’m very interested in how the environment shapes our physical activity behaviors, particularly our choices around transportation. I’ve been able to carve out a niche in understanding the current and emerging methods we use to monitor active transportation behaviors and the environmental elements that support these behaviors. I’m fortunate to be on a team that is tasked with performing this exact mission.

Why do you do what you do? I do what I do because I appreciate the dramatic health benefits that physical activity can offer and want more people to be able to enjoy these benefits. I firmly believe that human adults are not naturally inclined to be very active in our leisure time, and we need to be surrounded by environments and social norms that nudge us toward activity. I feel privileged to work, in a small way, toward this goal.

What are two key issues that must be addressed by 2030? First, continued improvement of methods to measure and catalog the environmental elements that support walking and other physical activities may help track progress. For example, we have clear national priorities for creating walkable environments, yet no comprehensive surveillance system exists to track the presence of sidewalks, a basic

element of walkability, across communities, states, or the nation.

Second, research into the impact of emerging mobility technologies on physical activity may help predict future trends. For example, e-scooters may make it easier for people to choose an inactive form of transportation over walking or bicycling (including bike share), especially for first- and last-mile connections to public transit. Also, what will the emergence of autonomous vehicles (e.g., self-driving cars) mean for physical activity, including walking and bicycling for transportation? What will people do with their time if they don’t have to drive?

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

There are many ways to assess physical activity. None are perfect, and all are subject to substantial errors in measurement. The total amount of energy expenditure due to physical activity is a small portion of the total daily energy expenditure. Domain-specific physical activity participation is important to measure so that the context of the behavior can be understood. The best way to assess physical activity is usually not with one instrument but with a set of instruments. The selection of an instrument should take into consideration whether you want to measure individuals or populations. Surveillance of physical activity is important for understanding trends in participation over time in populations. Several sources of surveillance data exist in the United States and throughout the world.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Blair SN, Haskell WL, Ho P, Paffenbarger RS, Vranizan KM,

Farquhar JW, Wood PD. 1985. Assessment of habitual physical activity by a seven-day recall in a community survey and controlled experiments. American Journal of Epidemiology 122: 794-804.

Bull FC, Maslin TS, Armstrong T. 2009. Global Physical Activity Questionnaire (GPAQ): Nine country reliability and validity study. Journal of Physical Activity and Health 6: 790-804.

Carlson SA, Densmore D, Fulton JE, Yore MM, Kohl HW III. 2009. Differences in physical activity prevalence and trends from 3 US surveillance systems. Journal of Physical Activity and Health 6 (Suppl 1): S18-S27.

Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, Pratt M, Ekelund U, Yngve A, Sallis JF, Oja P. 2003. International Physical Activity Questionnaire: 12-country reliability and validity. Medicine & Science in Sports & Exercise 35 (8): 1381-1395.

Declich S, Carter AO. 1994. Public health surveillance: Historical origins, methods and evaluation. Bulletin of the World Health Organization 72 (2): 285-304.

Global Observatory for Physical Activity. 2018. GoPA! www.globalphysicalactivityobservatory.com. Accessed 14 May 2018.

Hallal PC, Andersen LB, Bull FC, Guthold R, Haskell W, Ekelund U, Lancet Physical Activity Series Working Group. 2012. Global physical activity levels: surveillance progress, pitfalls, and prospects. The Lancet 380 (9838): 247-257.

Kohl HW III, Craig CL, Lambert EV, Inoue S, Alkandari JR, Leetongin G, Kahlmeier S, Lancet Physical Activity Series Working Group. 2012. The pandemic of physical inactivity: Global action for public health. The Lancet 380 (9838): 294- 305.

Kohl HW III, Kimsey CD Jr. 2009. Physical activity surveillance. In Lee, I-M, ed. Physical Activity Epidemiology. New York: Oxford University Press.

Kohl HW III, Lee I-M, Vuori IM, Wheeler FC, Bauman A, Sallis JF. 2006. Physical activity and public health: The emergence of a subdiscipline. Journal of Physical Activity and Health 3: 344- 364.

Pandemic. 2019. Merriam-Webster.com. https://www.merriam- webster.com/dictionary/pandemic. Accessed July 16, 2019.

Pettee Gabriel K, James J, McClain JJ, Schmid KK, Kristi L, Storti KL, Ainsworth BE. 2010. Reliability and convergent validity of the past-week Modifiable Activity Questionnaire. Public Health Nutrition 14 (3): 435-442.

Sallis JF, Bull F, Guthold R, Heath GW, Inoue S, Kelly P, Oyeyemi AL, Perez LG, Richards J, Hallal PC, Lancet Physical Activity Series 2 Executive Committee. 2016. Progress in physical activity over the Olympic quadrennium. The Lancet. 388 (10051): 1325-1336.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2015. Youth Risk Behavior Surveillance System (YRBSS).

www.cdc.gov/HealthyYouth/yrbs/index.htm. Accessed 14 May 2018.

U.S. Department of Health and Human Services. 2016a. Behavioral Risk Factor Surveillance System (BRFSS). www.cdc.gov/BRFSS. Accessed 14 May 2018.

U.S. Department of Health and Human Services. 2016b. National Health Interview Survey (NHIS). www.cdc.gov/nchs/nhis.htm. Accessed 14 May 2018.

U.S. Department of Health and Human Services. 2017. National Health and Nutrition Examination Survey (NHANES). www.cdc.gov/nchs/nhanes.htm. Accessed 14 May 2018.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf .

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.3, 1.1.5, 2.1.2, 2.1.3, 2.2.3, 2.3.2, 2.3.3, 2.5.2, 2.6.1, 2.6.2, 2.6.3, 3.2.1, 3.2.2, 3.7.1, 3.8.1, 3.8.2, 4.1.3, 4.1.4, 4.2.1, 5.5.5, 5.5.6, 5.5.7, 6.2.1, 6.3.1, 6.3.2, 6.3.5, 6.4.1, 6.4.2

PART II Health Effects of Exercise and Physical Activity

CHAPTER 5 Cardiorespiratory and Metabolic Health

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The impact of sedentary behavior and sedentary activity in relationship to physical activity and all-cause mortality

»  Cardiovascular disease risk factors, prevalence, and economic costs

»  The evidence of a correlation between physical activity and cardiorespiratory health

»  The physical activity and exercise recommendations for cardiorespiratory health

»  Metabolic diseases, their prevalence, and their risk factors »  The evidence of a correlation between physical activity

and metabolic health »  The physical activity and exercise recommendations for

metabolic health »  Testing methodologies used to predict and diagnose

cardiovascular and metabolic diseases

OPENING QUESTIONS »  What is the leading cause of death worldwide? »  How do metabolic diseases relate to the risk for developing

cardiovascular disease?

»  How much physical activity and exercise do people need to decrease their cardiovascular and metabolic health risks?

Part II of this textbook provides an overview of the scientific evidence that supports the health benefits of participation in regular physical activity and exercise. It also reviews the potential health risks associated with a lack of physical activity and exercise.

A primary benefit of engaging in physical activity and exercise is that doing so significantly reduces the risk of premature death (i.e., dying earlier than the average age of death for a specific population group) from any cause, or all-cause mortality, as compared to being inactive (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2008, 2018). As noted in the first edition of Physical Activity Guidelines for Americans (USDHHS 2008) and further supported by the 2018 PAGAC, the effects of physical activity and exercise on all- cause mortality are remarkable for two reasons:

• Only a few lifestyle choices have as large an effect on mortality as physical activity. It has been estimated that people who are physically active for approximately 7 hours per week have a 30 to 40% lower risk of dying early than those who are active less than 30 minutes per week.

• It is not necessary to do high amounts of activity or even vigorous-intensity activity to reduce the risk of premature death. Studies show a substantially lower risk of mortality when people do at least 150 minutes of moderate-intensity aerobic physical activity a week.

The main messages to share are that (1) research clearly demonstrates the importance of avoiding inactivity (sedentary behavior and physical inactivity, see chapter 2) and (2) some physical activity is much better than none at all, because there is a dose-response relationship between the amount of physical activity and risk of poor health. Figure 5.1 illustrates the relationship between the risk of all-cause mortality (reported in the 2008 PAGAC), perhaps the ultimate indicator of poor health, and the minutes per week of moderate- or vigorous-intensity physical activity and exercise. As you can see, the risk of dying prematurely is lower when one is physically active for 1.5 to 2.5 hours per week versus for only 30 minutes per week. Moreover, the risk continues to decline with higher amounts of physical activity. Thus, people who are more active are better off than those who are inactive or somewhat active. The 2018 PAGAC extended and supported the recommendations of the 2008 PAGAC by citing evidence from Moore and colleagues (2012) who extensively studied the effects of moderate-to-vigorous physical activity and all-cause mortality in adults, aged 21-90, and found the following:

1. The beneficial effect of physical activity has no lowest threshold. 2. The slope is steepest at the lowest amounts of moderate-to-

vigorous physical activity.

3. At least 70% of the potential benefit on all-cause mortality is reached by achieving 8.25 MET-hours (150 min) per week of moderate-to-vigorous physical activity.

4. There is no obvious best amount. 5. There is no apparent upper threshold. 6. Benefits continue to accrue as more physical activity is accrued. 7. Activity volumes of up to four times the 2008 guidelines (150-

300 minutes of moderate-intensity physical activity) show no evidence of increased mortality risk.

As you previously learned in chapter 2, sedentary behavior and physical inactivity are inconsistent with promoting health for individuals or populations. In 2016, Ekelund and colleagues noted that lack of physical activity increases the risks of many noncommunicable diseases such as type 2 diabetes, cardiovascular disease, stroke, some cancers, and premature mortality. However, sedentary behavior also appears to be a potential risk factor for many chronic conditions and mortality. The authors conducted a study that included over one million subjects in order to examine the associations of sedentary behavior and physical activity with all- cause mortality. They concluded that increased sitting time is associated with increased all-cause mortality; however, the level of increased risk with increased sitting time is reduced in physically active people. Individuals who are active about 60 to 75 minutes per day in moderate-intensity physical activity seem to have no increased risk of mortality, even if they sit for more than eight hours per day. Thus, the current scientific evidence indicates lack of physical activity impacts all-cause mortality significantly more than sedentary behavior and sedentary activity.

Figure 5.1   The risk of dying prematurely declines as people become physically active. Reprinted from USDHHS, PAGA (2008).

The health benefits of physical activity and exercise (i.e., lowering the risk of all-cause mortality) apply equally for men and women, adults of all ages, and active people of all body weights (normal, overweight, and obese), but there is insufficient evidence available to determine whether these relationships vary by ethnicity or socioeconomic status. This chapter addresses the specifics of how participation in physical activity and exercise has positive health effects related to cardiovascular health and metabolic health based on updates in the relevant literature and the 2018 PAGAC.

According to the Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC 2008, 2018), cardiovascular disease (CVD) and the underlying metabolic disorders (e.g., metabolic syndrome and diabetes mellitus) can be prevented and treated with physical activity. Although people can be independently diagnosed with CVD, metabolic syndrome, or diabetes, all of these health

challenges can, and commonly do, occur together. People with these diseases commonly have other chronic health issues and have not been physically active.

Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels that include the following:

Coronary heart disease (CHD or ischemic heart disease, heart attacks) Cerebrovascular disease (stroke) Elevated blood pressure (hypertension) Peripheral artery disease Rheumatic heart disease Congenital heart disease Heart failure

Numerous risk factors (lifestyle or genetic variables that can predict the occurrence of disease) are known to contribute to the development of CVD. In turn, many of these are modifiable with regular physical activity and exercise. Elevated blood pressure, poor lipid and lipoprotein profiles, low cardiorespiratory fitness, and high body fat levels are but a few of these risk factors for CVD. To state this another way, physical activity and exercise are thought to reduce the risk of CVD in two ways: (1) by reducing other risk factors for the disease and (2) by playing a direct role in the physiological changes at the cellular level and in the blood vessels, the impairment of which contributes to CVD. Common respiratory disorders such as chronic obstructive pulmonary disease can also contribute to increased CVD risk and decreased cardiorespiratory function, but are most modifiable by other interventions such as smoking cessation. As noted in chapter 2, regular physical activity and exercise can also improve cardiorespiratory fitness, which can reduce CVD risk.

Metabolic risk factors contribute to a variety of conditions that increase the risk of CVD development. Metabolic syndrome is a cluster of clinical characteristics that has been defined differently in

the past by several organizations (e.g., the U.S. National Cholesterol Education Program and the World Health Organization [WHO]), but it has the following similar profiles in adults and adolescents:

Abnormal levels of lipids and lipoproteins (low high-density lipoprotein [HDL] levels and high triglyceride levels with small, dense low-density lipoprotein [LDL], or atherogenic dyslipidemia) Elevated fasting glucose or insulin levels Hypertension Excess abdominal obesity (USDHHS, PAGAC 2008; Alberti et al. 2009)

Diabetes mellitus (or diabetes) is a syndrome associated with low insulin secretion, a limited ability of insulin to act on target tissues to maintain glucose homeostasis, or both of these conditions. Glucose is a main source of energy for the human body, and glucose levels must be kept in equilibrium so the body’s metabolic processes can continue. Metabolic dysfunction (including some, if not all, of the conditions described for metabolic syndrome) is commonly seen in people diagnosed with diabetes. As discussed later in the chapter, CVD, metabolic syndrome, and type 2 diabetes can all be prevented or managed by engaging in appropriate, regular physical activity and exercise.

Diabetes can be further defined as type 1 and type 2. In people with type 1 diabetes (the more rare of the two), the immune system attacks and destroys the insulin-producing beta cells of the islets of Langerhans in the pancreas. Type 1 diabetes is treatable with insulin and usually affects children and adolescents (it is also called juvenile diabetes or insulin-dependent diabetes), but it can occur in adults after a viral infection or as postgestational diabetes in women who become pregnant after age 35.

Type 2 diabetes (adult-onset, non-insulin-dependent diabetes mellitus, or NIDDM) is related to overweight, obesity, and insulin resistance (IR, impaired glucose homeostasis). In people with this

condition, the pancreas cannot secrete enough insulin to compensate for the IR, which results in high blood glucose and high lipid levels. People with type 2 diabetes usually have the risk factors associated with metabolic syndrome, and they are at a higher risk for developing CVD.

PREVALENCE OF CARDIOVASCULAR DISEASE As a whole, CVDs are the number one cause of death globally. The WHO (2017) reported CVDs as the cause of over 31% of all global deaths, and 17.9 million people died from CVDs associated with CHD and stroke (see Chapter 1). The leading causes of death (heart disease, some cancers, stroke, and diabetes) have remained fairly stable since 2008, and participating in regular physical activity and exercise can decrease the risk of dying from all four.

Looking to the future, the WHO (2015) reported that the global burden of CVD is most likely to continue. In 2015 an estimated 20 million people died from CVD. This represents a monumental shift, as mentioned in chapter 1, away from infectious diseases and toward chronic (noncommunicable) diseases as the leading causes of death. This also presents a terrific opportunity, given the positive influence that physical activity has on many chronic diseases.

In addition to the health costs of CVD, there are economic costs to consider: individual and family health care, time lost from work, costs to government and industry for health care, and health care costs to countries due to lost productivity. The American Heart Association (2017) estimated the direct costs (e.g., physician care and medications) and indirect costs (e.g., mortality and morbidity) of CVD and stroke in the United States at $316.1 billion dollars for 2012-2013. As a comparison, the cost of cancer in the United States was $80.2 billion for 2015 (American Cancer Society).

RISK FACTORS FOR CARDIOVASCULAR DISEASE Numerous CVD risk factors have been identified in the scientific literature, many of which can be reduced by participating in regular

physical activity and exercise. The major risk factors for CVD are divided between those that are modifiable (i.e., something can be done about them) and those that are nonmodifiable (i.e., not changeable). Modifiable Risk Factors for CVD

Hypertension Atherogenic dyslipidemia Tobacco use Physical inactivity Obesity Metabolic syndrome Diabetes mellitus Elevated inflammation biomarkers (e.g., C-reactive protein)

Nonmodifiable or Less Modifiable Risk Factors for CVD

Age Sex Heredity (genetics) Ethnicity or race

The modifiable risk factors often can be significantly altered with lifestyle changes or pharmaceutical interventions. Nonmodifiable risk factors are often regulated by behavioral interventions (e.g., physical activity and exercise) that influence molecular and cellular changes based on individual or clusters of genes.

Even though these risk factors have been traditionally thought of as binary (modifiable or nonmodifiable but not both), recent research suggests that this may not always be the case—that is, a person’s genetic code for disease may actually be influenced by external factors such as physical activity and exercise. For example, engaging in regular physical activity and exercise appears to affect epigenetic markers (i.e., regulators of gene function) that cause the

down-regulation (repression) or up-regulation (enhanced expression) of specific genes. This in turn may influence the disease processes. In some cases a down-regulation of a gene or series of genes would reduce risk, whereas in other cases an up-regulation would be considered a positive effect. For example, if a person is at risk for developing hypertension because both parents have the disease, participating in regular physical activity and exercise can lower that person’s hypertension and CVD risk, despite any genetic predisposition.

Following are descriptions of the modifiable and nonmodifiable risk factors for CVD:

• Hypertension. Hypertension is a major risk factor for stroke and other CVDs, especially if blood pressure is uncontrolled and >130/80 mmHg (Whelton et al. 2017). Even somewhat elevated blood pressure (120-129/<80) can indicate an increased risk of CVD. Hypertension exhibits few symptoms, but it is associated with heredity, aging, physical activity, diet, obesity, and alcohol consumption. Hypertension is the most common, costly, and preventable CVD risk factor.

• Atherogenic dyslipidemia. Elevated total cholesterol (>200 mg/dl), high levels of LDL cholesterol (>100-130 mg/dl), low levels of HDL cholesterol (<40 mg/dl for men and <50 mg/dl for women), and high levels of triglycerides are associated with greater risk for CVD.

• Tobacco use. Smokers have two to three times the risk for CVD that nonsmokers have, and they tend to be less physically active than nonsmokers. Quitting smoking reduces CVD risk and may facilitate greater participation in regular physical activity and exercise.

• Physical inactivity. Physical inactivity is a risk factor for CVD independent of other risk factors.

• Obesity. A body mass index (BMI) >25 kg/m2 (overweight), or >30 kg/m2 (obese) increases CVD risk and is highly correlated to metabolic disorders.

• Diabetes mellitus. Diabetes mellitus doubles the risk of developing CVD compared to those without the disease. Blindness, limb amputation, and renal nephropathy are health problems that arise when diabetes (type 1 or 2) is not controlled.

• Metabolic syndrome. Metabolic syndrome is identified as a cluster of abnormal characteristics (see the preceding definition of metabolic syndrome) associated with prolonged sitting, poor diet, and sedentary behaviors. Generally three abnormal findings out of five would qualify a person for the metabolic syndrome (Alberti et al. 2009).

• Elevated inflammation biomarkers. C-reactive protein (CRP) is one of several biomarkers and responses to internal systemic inflammation that have been found to be associated with the development of atherogenic plaques, plaque rupture, or both (i.e., increased CVD risk).

• Age. Advancing age (men >40, women >50) is associated with increased CVD risk because of changes in vascular health (vasodilation versus vasoconstriction with or without artery narrowing) due to vascular stiffening.

• Sex. Men are at a higher risk for CVD than women at an earlier age; however, women’s risk for CVD increases significantly postmenopause.

• Heredity (genetics). Genetics can account for 20 to 50% or more of the variability in people’s CVD risk, which can predispose them to a lower or higher overall CVD risk. However, individual lifestyle and health behaviors can significantly reduce CVD risk.

• Ethnicity or race. Evidence supports the fact that some groups have higher rates of CVD than others (e.g., African Americans have higher stroke rates than other Americans). Contributing factors to ethnicity and race may include socioeconomic status and stress.

CARDIORESPIRATORY HEALTH BENEFITS FROM PHYSICAL ACTIVITY AND EXERCISE

Physiological

Lower resting heart rate

Greater stroke volume

Increased O2max Increased ventilatory fatigue

Increased arteriovenous oxygen difference (AV O2 diff) (max)

Lower submaximal blood pressure

Increased lactate threshold (max)

Improved functioning of autonomic nervous system

Improved endothelial function

Reduced inflammation due to oxidative stress

Increased total energy expenditure

Increase in oxidative enzymes

Increase in anaerobic enzymes

Improved glucose homeostasis

Reduced body fat

Reduced waist girth

Increased muscular strength

Increased muscular endurance

Lower total cholesterol level

Increased HDL cholesterol level

Lower triglyceride level

Biomechanical

Improved economy

Increased motor skill and confidence to engage

further in physical activity and exercise

Improved proprioception, which helps coordination

system response and balance

Behavioral

Increased self-confidence

Improved self-efficacy

Decreased depression and anxiety

Experience with behavioral change

Improved stress management

Improved sleep patterns

Based on information from Physical Activity Guidelines Advisory Committee Report (USDHHS, PAGAC, 2008, and 2018), American Heart Association, American Diabetes Association, and the CDC.

KINESIOLOGY AND CARDIORESPIRATORY HEALTH A general understanding of several of the exercise sciences is helpful for understanding the effects of physical activity and exercise on health outcomes such as cardiorespiratory health. Recall from chapter 2 that we are focusing on three key domains of kinesiology that guide the health aspects of physical activity: exercise physiology, the movement sciences, and the behavioral sciences.

The highlight box Cardiorespiratory Health Benefits From Physical Activity and Exercise contains some of the desired exercise-related adaptations in each of these three areas that positively influence cardiorespiratory health. Practitioners should be able to explain the common changes that can occur following participation in regular personalized or targeted population physical activity and exercise programs (refer to the Scientific Evidence and Guidelines sections later in the chapter).

Physical activity and exercise improve cardiovascular function by lowering resting heart rate and increasing stroke volume during submaximal workloads. During moderate-intensity physical activity, comparing pretraining to posttraining workloads, most people have lower heart rates and blood pressures for the same amount of work. The muscles used for breathing (intercostals and abdominals) become more resistant to fatigue, and people can work for longer

periods. The maximal cardiorespiratory endurance ( O2max) increases along with the ability to extract oxygen for muscle activity (AV O2 diff).

The Fick equation, shown next, shows the central (pump function) and peripheral (muscle function) components of the cardiorespiratory system, and both parts can adapt specifically to provide increases in cardiorespiratory capacity after conditioning. Maximal heart rate (MHR) and stroke volume (the squeeze of the heart with each beat, SV) make up the pump function components, whereas AV O2 diff represents muscle adaptations of increasing oxygen extraction:

O2max = (MHR × SV) × AV O2 diff

WHY IS THE FICK EQUATION IMPORTANT? Different types of physical activity affect different parts of the circulatory system. For example, some people (e.g., those with heart disease) may not be able to strengthen their heart as much as they can improve their peripheral circulation (and therefore improve their health). However, a healthy person should expect to see improved pump function (due to increases in SV) and improved peripheral function (due to increases in AV O2 diff).

MHR typically stays the same or decreases slightly with training (as a result of an increase in SV, the heart needs more time to fill); AV O2 diff also increases. The lactate threshold (LT) (i.e., point of increased lactic acid accumulation, which is associated with recruiting more fast-twitch muscle fibers) typically improves from ~50% of O2max to ~75% of O2max.

Reductions in the percentage of body fat are often observed over time during physical activity and exercise training along with reductions in waist girth. The muscles used during aerobic activities show improvements in strength and endurance (as compared to

baseline). Regular participation in physical activity and exercise is associated with an improved atherogenic dyslipidemia profile that includes lower total cholesterol, increased HDL cholesterol, and lower triglyceride levels. Improvements in autonomic nerve function, increases in aerobic and anaerobic enzymes, improved glucose homeostasis, improved endothelial function, and reduced inflammation related to oxidative stress are also common physiological adaptations observed with regular physical activity and exercise. Figures 5.2 through 5.4 illustrate common changes in cardiorespiratory function after physical activity or exercise training.

Figure 5.2    Significant increase in O2max shown after one year of intensive exercise training in an untrained person. Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport and Exercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 269.

Figure 5.3   Some elite individuals have the genetic ability for stroke volume to continue to increase with exercise workload instead of plateauing like most people. Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport and Exercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 273.

Figure 5.4   Significant changes in heart rate after exercise training encompassing walking, jogging, and running. Reprinted by permission from L. Kenney, J. Wilmore, and D. Costill, Physiology of Sport and Exercise, 7th ed. (Champaign, IL: Human Kinetics, 2020), 275.

Movement-wise, people who become physically active experience improved economy (i.e., a reduced oxygen–energy cost at a given speed or workload), which is a function of improved efficiency (this is complicated to actually measure). They also develop motor skills and often gain more confidence to engage in future physical activity and exercise activities. Peripheral proprioception (i.e., the sense of position and movement) response and balance often improve as well.

From a behavioral science standpoint, people undertaking physical activity or exercise training likely experience several of the steps of behavioral change (contemplation, preparation, action, maintenance, relapse) and learn to cope with the unique challenges of each step. By experiencing the stages of behavioral change,

people acquire coping skills and strategies that help them remain in the maintenance stage for activity; they also avoid long periods of relapse as a result of overuse injuries, boredom, or lifestyle schedule changes.

SECONDARY PREVENTION OF CVD Does being physically active or participating in regular exercise help in the secondary prevention (like surviving a myocardial infarction [MI], or heart attack) of CHD and other atherosclerotic diseases? According to research reported by the American Heart Association (AHA) and the American College of Cardiology (ACC) the answer is, yes! The clinical practice of having cardiac patients participate in multidisciplinary (including physical activity and exercise) cardiac rehabilitation programs has been shown to stabilize, slow, or even reverse the natural progression of the underlying atherosclerotic process. Participation in exercise-based cardiac rehabilitation programs within the first six months of a cardiac event has been shown to reduce total mortality for patients by 20% and cardiac mortality by 26%.

Comprehensive cardiac rehabilitation includes baseline patient assessments, risk factor interventions (smoking cessation, hypertension management, lipid management, diabetes management, and weight control), physical activity counseling and exercise training, nutritional counseling, psychosocial counseling, and vocational counseling. Cardiac rehabilitation programs have traditionally included three phases with the following objectives related to physical activity and exercise interventions:

Phase 1 involves inpatient programming (2-3 days for

an uncomplicated MI) with education, baseline data

collection, identification of physical limitations,

and physical activity to avoid the negative effects

of prolonged bed rest and inactivity.

Phase II involves outpatient programming (4 weeks or

12 visits) that is often supervised in the clinical

setting, but can also be monitored via new

technologies from the patient’s home. Prior to

exercise programming, patients should be evaluated

with diagnostic graded exercise testing with

physician supervision and an exercise prescription

that may include clinical supervision. Most patients

are then encouraged to accumulate 30 to 60 minutes of

moderate- intensity aerobic activity, preferably all

days of the week, and they are encouraged to acquire

two days per week of resistance training.

Phase III usually involves voluntary patient

participation in outpatient programs like those at

local hospital-based fitness centers or YMCAs. In

Phase III cardiac rehabilitation programming (>12

weeks posthospital discharge), patients are

encouraged to at least maintain Phase II levels of

physical activity and exercise.

Phases I and II of cardiac rehabilitation programs are usually covered by personal insurance for a specified period of time or number of visits (e.g., 12 visits in Phase II cardiac rehabilitation). However, Phase III cardiac rehabilitation costs are covered directly by patients. The safety of participating in medically supervised cardiac rehabilitation programs is well documented and has been shown to be safe and effective with only two fatalities reported in 1.5 million patient- hours of exercise. Unfortunately, only about 10 to 20% of cardiac patients (approximately >2 million) participate in cardiac rehabilitation programs yearly, which means that many individuals do not regain or achieve basic functional health levels associated with higher levels of quality of life.

Some additional health benefits of participation in regular physical activity and exercise that have been reported for cardiac rehabilitation patients include:

greater exercise capacity, improved success when returning to work, improved cardioprotective mechanisms, reduced anxiety, improved self-esteem, and better overall quality of life.

Adapted from AHA 2005 and AHA and ACC 2006.

Some people report that they feel better and have more self- confidence after several weeks of participation in physical activity and exercise. Many report experiencing lower levels of depression and anxiety, and higher self-efficacy (i.e., personal accomplishment and well-being) levels. Participation in physical activity and exercise has been shown to be a very useful stress management tool and effective for improving sleep patterns.

CARDIORESPIRATORY FITNESS ASSESSMENTS Many tests that require maximal or submaximal work levels have been developed and used by exercise physiologists and medical specialists to measure changes in cardiorespiratory fitness or function (CRF). The CRF measures and tests described here promote cardiorespiratory health and the prevention of CVDs. People with a diagnosed CVD should seek clinical and rehabilitation advice before undertaking physical activity and exercise programs.

When evaluating CRF, two helpful clinical measures to acquire are O2max and O2peak (the highest O2 uptake value or workload obtained by a person without achieving true maximal criteria), which represent valid measures or estimates of aerobic power (see chapter 2 to review aerobic power and O2max). The percentage of O2max is also important clinically and can be used to determine intensity over an extended time, or for bouts of physical activity and exercise. Exercise physiologists consider the measurement of O2max to be one of the single best predictors of overall CRF.

Graded exercise testing (GXT) is most commonly used to measure or estimate O2max (see www.acsm.org and figure 5.5 for more on GXT testing). The GXT protocol selection should be based

on target goals, physical abilities, and clinical considerations. By determining a person’s O2max, a practitioner can calculate maximal working capacity or absolute intensity (see chapter 2) and classify physical activity and exercise workloads accordingly (see figure 2.4).

Figure 5.5   Graded exercise testing.

Figure 5.6 illustrates the expected change in CRF (as measured by O2peak) with increasing doses or volumes of physical activity and exercise. Of course, all changes depend on factors such as baseline fitness, sex, age, BMI, and genetics.

Having determined the percentage of O2max that people can work at for several minutes or for multiple short bouts throughout a day, practitioners can calculate their relative intensity as described in chapter 2. They can measure or estimate the percentage of O2max by using any protocol that requires self-selected physical activity or exercise at moderate-to vigorous-intensity levels for 20 to 30 minutes, or for three bouts of ~10 minutes per day.

Can CRF be estimated without a laboratory and a treadmill or without doing maximal testing? Yes it can, because significant positive relationships exist among heart rate responses, speed of walking or running, and increasing workloads (resistance) with increasing oxygen uptake and O2max. Several field assessments can be used as maximal or submaximal tests. Typically, maximal testing (e.g., running on a treadmill to exhaustion) works best with low risk, younger, healthy populations. Submaximal tests can be used with all populations except those with diagnosed CVD, those at high risk for CVD, or those with orthopedic challenges who often require medical supervision for CRF evaluation (see ACSM [2018] for more on supervised exercise testing).

Figure 5.6   Changes in O2peak by exercise group. Reprinted from USDHHS, PAGAC (2008).

Distance run tests (1-mile run, 1.5-mile run, 12-minute run), the 1- mile walk, cycle tests, step tests lasting 3 to 5 minutes, and nonexercise prediction equations are all commonly used to predict O2max and have acceptable errors of <1 MET. It is also possible to estimate O2max using nonexercise protocols (e.g., questionnaires). The following commercial websites have listings of simple nonlaboratory CRF tests with procedures, online calculators, and interpretation explanations that can make the assessment of CRF more time and cost effective: www.exrx.net, www.brianmac.co.uk, and www.topendsports.com.

Once O2max has been estimated, an easy way to predict the percentage of O2max at which a person can work is to use a method first described by Ross and Jackson (1986). In this method, the person is asked to perform a 20- to 30-minute walk/jog evaluation that requires them to measure their heart rate immediately upon completing the assessment. The following equation can be used to calculate the percentage of O2max:

% of O2max = (heart rate in beats/min − k) × 100 / (220 − age − k)

in which k = 61 for males and 73 for females, and age is expressed in years.

An initial goal for many people would be to maintain ~50% of their initial O2max. A goal of ~75% is reasonable for those who want to improve their CRF. By comparing the relative intensity that people can maintain with the absolute intensity they can achieve, practitioners can help them achieve additional cardiorespiratory health and performance goals.

GENERAL RECOMMENDATIONS FOR CARDIORESPIRATORY HEALTH As shown in figure 2.3 the relationships between the risks of CHD and stroke, and the volume (frequency, bout intensity, time or duration, and longevity of the program) of physical activity and exercise, are dose dependent. Figure 2.3 shows that CHD risk drops dramatically with moderate amounts of physical activity and exercise volume, whereas the relationship for stroke risk is more of an L shape and drops with a greater (but not too much) physical activity and exercise volume.

As early as 1961, an ad hoc committee of the AHA released a report that recommended that physical activity or exercise be part of the strategies to positively influence plasma lipid and lipoprotein levels that can reduce the risks of heart attacks and stroke (Gotto 1989). The report specifically stated that “overweight persons should decrease their caloric intake and attempt to achieve a desirable body weight, and weight reduction should be facilitated by regular moderate exercise.” The work of Mitchell and colleagues (McGuire et al. 2001) also supports the assertion that physical activity is very important for the maintenance of cardiorespiratory capacity.

Today, over 50 years later, it is not surprising that many more recommendations to engage in physical activity and exercise to

promote public health exist. The following section highlights evidence-based recommendations from the PAGAC (USDHHS, PAGAC 2008, 2018) regarding the use of physical activity and exercise to improve cardiorespiratory health.

SCIENTIFIC EVIDENCE The 2008 PAGAC cited strong scientific evidence that supports an inverse relationship between the volume of physical activity and exercise and incidences of CVD (CHD, stroke, hypertension, and atherogenic dyslipidemia). Regular physical activity and exercise improves cardiorespiratory fitness and lowers the risk for CVD, CHD, and stroke by 20 to 35%. The benefits of physical activity and exercise on cardiorespiratory health apply equally for men and women of all ages, and there was no evidence for racial or ethnic differences when adjusted for volume in the 2008 Report.

The 2018 PAGAC extensively reviewed 10 years of evidence since the first PAGAC and provides more precision to the current public health recommendations. The 2018 report focused on CVD mortality that included CVD in the broadest sense: stroke and ischemic heart failure. The committee found the following:

Strong evidence demonstrates a clear inverse dose-response relationship between the amount of moderate-to-vigorous physical activity and all-cause mortality. The strength of the evidence is very unlikely to be modified by more studies of these outcomes. The relationship of moderate-to-vigorous physical activity and risk reduction has no lower limit. Risk appears to continue to decrease with increased exposure up to at least three to five times the amount of the lower bound of moderate-to-vigorous physical activity recommended in the 2008 Guidelines (i.e., 150 minutes per week). The new data are consistent with those used to develop the 2008 Guidelines.

Strong evidence demonstrates that the dose-response relationships between moderate-to-vigorous physical activity and all-cause mortality do not vary by age, sex, race, or weight status. Insufficient evidence is available to determine whether these relationships vary by ethnicity or socioeconomic status.

The effective dose of physical activity and exercise for cardiorespiratory health in 2008 was reported to be at least 800 MET-minutes per week (see chapter 2 to review the MET-minute concept) or 12 miles (19.3 km) per week (moderate intensity, vigorous intensity, or a combination). The public health target in the 2008 Scientific Report was 500 to 1,000 MET-minutes of moderate- to-vigorous physical activity (or 150 to 300 minutes per week of moderate-intensity physical activity). The 2018 Committee supports the recommendations of the 2008 Report. Unfortunately, only half the U.S. adult population meets this level of physical activity. Thirty percent of the population does no moderate-to-vigorous physical activity, even though major improvements in health can occur for many Americans with modest increases in regular physical activity.

Strong evidence was also found to support positive CRF benefits from walking briskly for at least two hours per week and participation in aerobic activities in addition to the usual activities of daily living. The reduction of CVD risk begins to decrease once people drop below the dose threshold. Data to support the notion that an accumulation of daily bouts of physical activity and exercise can lower CVD risk were limited in 2008, but people were encouraged to accumulate multiple 10-minute bouts throughout the day. Evidence in the 2018 Report indicates that bouts of any length of moderate-to- vigorous physical activity contribute to the health benefits associated with accumulated volume of physical activity.

GUIDELINES

This section contains guidelines for physical activity participation to maximize cardiorespiratory health. Special precautions are noted for people with diagnosed or preexisting CVD. For example, beginning an exercise program can be particularly dangerous for a person with uncontrolled hypertension. In this case, blood pressure should be lowered by pharmaceutical intervention prior to participating in any form of substantial physical activity. Once the blood pressure has been controlled, physical activity can be added as part of the management regimen. The guidelines for cardiorespiratory health can be divided into three parts: children and adolescents (ages 6 to 17), adults (ages 18 to 64), and older adults (>65 years).

Children and adolescents should acquire 60 minutes or more of daily physical activity and exercise for cardiorespiratory health. Most of the 60 minutes should include either moderate- or vigorous- intensity aerobic physical activity or exercise. Youth should include vigorous-intensity physical activity or exercise at least three days per week. They should also be encouraged to participate in physical activities that are appropriate for their age, are enjoyable, and offer variety. Table 5.1 contains examples of moderate-intensity and vigorous-intensity aerobic activities for children and adolescents, adults, and older adults.

Table 5.1   Examples of Moderate-Intensity and Vigorous-Intensity Aerobic Physical Activity by Age Group

Population

Type of aerobic physical activity

Moderate intensity Vigorous intensity

Children and adolescents

Active recreation such as

hiking, skateboarding, in-

line skating (or canoeing for

adolescents)

Bicycle riding (stationary or

road biking for adolescents)

Brisk walking

Housework and yard work, such

as sweeping or pushing a lawn

mower (adolescents)

Games that require catching

and throwing, such as

baseball and softball

(adolescents)

Active games involving

running and chasing, such as

tag (or flag football for

adolescents)

Bicycle riding

Jumping rope

Martial arts, such as karate

Running

Sports such as soccer, ice

or field hockey, basketball,

swimming, and tennis

Cross-country skiing

Vigorous dancing

(adolescents)

Adults Walking briskly (3 mph, or

4.8 km/h) or faster, but not

racewalking

Water aerobics

Bicycling slower than 10 mph

(16 km/h)

Tennis (doubles)

Ballroom dancing

General gardening

Racewalking, jogging, or

running

Swimming laps

Tennis (singles)

Aerobic dancing

Bicycling 10 mph (16 km/h)

or faster

Jumping rope

Heavy gardening (continuous

digging or hoeing, with

heart rate increases)

Hiking uphill or with a

heavy backpack

Older adults

The intensity of these activities can be either relatively

moderate or relatively vigorous, depending on an older

adult’s level of fitness.

Walking

Dancing

Swimming

Water aerobics

Jogging

Aerobic exercise classes

Bicycle riding (stationary or on a path)

Some gardening activities, such as raking and pushing a lawn

mower

Tennis

Golf (without a cart)

Adapted from USDHHS, PAGA (2008).

For substantial cardiorespiratory health benefits, adults should do at least 150 minutes (2 hours and 30 minutes) per week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) per week of vigorous-intensity, aerobic physical activity or exercise, or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity or exercise. Aerobic activity should be performed in episodes of at least 10 minutes and preferably spread throughout the week. For additional cardiorespiratory health benefits, adults should increase their aerobic physical activity or exercise to 300 minutes (5 hours) per week of moderate-intensity, or 150 minutes of vigorous- intensity physical activity or exercise, or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity or exercise. All adults should avoid inactivity. Some physical activity is better than none, and adults who participate in any amount of physical activity or exercise gain some health benefits.

For substantial cardiorespiratory health benefits, older adults should follow the guidelines for adults, but consider the following special situations:

When older adults cannot do 150 minutes of moderate-intensity aerobic activity per week because of chronic conditions, they should be as physically active as their abilities and conditions allow. Older adults should determine their level of effort for physical activity relative to their level of fitness (see the discussion of the OMNI scale in chapter 2).

Older adults with chronic conditions should understand whether and how their conditions affect their ability to do regular physical activity and exercise safely.

PREVALENCE AND ECONOMIC COSTS OF METABOLIC DISEASE Various sources estimate that over 1 billion people globally have the cluster of factors as described at the beginning of the chapter associated with metabolic syndrome, and 422 million worldwide have diabetes (Mathers and Loncar 2006). About one-third of those people are unaware of their condition because the early symptoms are mild. The prevalence of metabolic syndrome varies with the current definition (Alberti et al. 2009), but it is estimated that between 22.9 to 34% of the population in the United States have metabolic syndrome (AHA 2017). The estimates for metabolic syndrome may also vary based on genetics, age, and ethnicity. As noted previously in the chapter, metabolic syndrome is associated with a cluster of factors, and researchers have found that these factors are consistent with the dramatic increase in obesity, not only in the United States, but also globally. Cardiovascular disease and type 2 diabetes have been identified as primary clinical outcomes of metabolic syndrome, but those with metabolic syndrome are also at increased risk for other conditions such as hypertension, abnormal lipid levels, asthma, sleep disturbances (sleep apnea), and some forms of cancer.

In 2015, about 9.4% of the U.S. population was estimated to have type 1 diabetes (5 to 10% of diagnosed cases) or type 2 diabetes (90 to 95% of diagnosed cases) (CDC 2017). People with diabetes are at high risk for developing heart disease and stroke. Diabetes is the leading cause of adult blindness and kidney failure and causes 60% of nontraumatic lower-limb amputations each year (National Diabetes Education Program 2005).

In the United States, the prevalence of diabetes is higher among Hispanics, African Americans, and Native Americans than among non-Hispanic Caucasians. Figure 5.7 shows the prevalence of

diabetes in the United States in 1994, 2000, and 2015. The prevalence of type 2 diabetes in children and adolescents has also increased significantly in the past 10 years, which is alarming because type 2 diabetes was rarely seen previously except in middle-aged adults.

The economic cost of metabolic syndrome is difficult to estimate because of varying methods of establishing a diagnosis (see next section). However, the estimated costs of diabetes in the United States in 2018 (ADA 2018) was estimated to be $327 million: $237 million was related to direct diabetes care, and $90 million in lost productivity. Another major economic challenge will be the future cost of diabetes, because experts estimate that 84.1 million adults (age 18 and older) have prediabetes, which includes blood glucose levels that are higher than normal but not high enough to indicate a diagnosis of diabetes.

Figure 5.7   Comparison of U.S. diabetes prevalence in adults for 1994, 2000, and 2015. Reprinted from Centers for Disease Control and Prevention (2017). Available: www.cdc.gov/diabetes/statistics

Table 5.2   Criteria for Clinical Diagnosis of Metabolic Syndrome Risk factor Criteria

Abdominal obesity (elevated waist circumference)

Population- and country- specific

Triglycerides ≥150 mg/dl

HDL cholesterol

   Men <40 mg/dl

   Women <50 mg/dl Blood pressure ≥130/≥85 mmHg

Fasting glucose >100 mg/dl

Reprinted from NIH and NHLBI (2004); K.G.M.M. Alberti et al., “A Joint Interim Statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International

Association for the Study of Obesity,” Circulation 120 (2009): 1640-1645.

METABOLIC DISEASE RISK FACTORS As you learned earlier in the chapter, various risk factors are associated with CVD as well as for metabolic syndrome and for diabetes. Table 5.2 (Alberti 2009) outlines the criteria and the risks associated with developing metabolic syndrome (three of five of the risk factors). Abdominal obesity is one of the metabolic risks that has been recommended to be evaluated based on population differences and ethnic groups.

The risk factors for diabetes are essentially the same as those for metabolic syndrome but also include the following:

Family history of diabetes Ethnicity or race: Hispanics, African Americans, Asians, and Native Americans are at higher risk Sedentary lifestyle History of CVD

The risk factors for metabolic syndrome and diabetes are closely related to those for CVD. However, both physical activity and

exercise play a very important role in the prevention and treatment of metabolic syndrome and diabetes.

KINESIOLOGY AND METABOLIC HEALTH You learned about the interrelationships of the exercise sciences, and the effects of physical activity and exercise on public health outcomes and cardiorespiratory health earlier in the chapter. The exercise science–related adaptations that positively influence metabolic health are basically the same as those listed in the Cardiorespiratory Health Benefits From Physical Activity and Exercise highlight box.

You should be able to explain the common metabolic changes that can occur after participation in regular personalized physical activity and exercise programming (see Scientific Evidence and Guidelines sections). Following are specific metabolic adaptations that are expected as a result of physical activity:

Increased total energy expenditure (helps maintain energy balance) Improved protein synthesis rate and amino acid uptake into skeletal muscle Reduced low-density lipoprotein levels Reduced triglyceride levels Increased high-density lipoprotein levels Improved glucose tolerance

One way to improve glucose uptake by skeletal muscles is to increase the gene expression of GLUT-4, which is a protein that is metabolically required for insulin to increase glucose uptake. GLUT-4 levels increase with regular physical activity and exercise, and they drop with physical inactivity and weight gain, which promotes insulin resistance.

Scientists have identified or are currently studying many other mechanisms associated with physical inactivity that can either initiate

or compound the effects of insulin resistance. By improving their metabolic health, people also benefit by achieving the behavioral and movement science–based changes associated with participating in regular physical activity and exercise, which can improve their future quality of life. Figure 5.8 shows the dose-response curves for moderate-to-vigorous physical activity and relative risk of type 2 diabetes.

COMMON TESTS OF METABOLIC FUNCTION Physicians can evaluate patients for metabolic syndrome using the common clinical measures of blood glucose listed in table 5.2. The measurements of height, weight, girth, blood pressure, and metabolic blood values are all part of most regular medical checkups. Although a diagnosis of metabolic syndrome does not necessarily mean that the person has a clinical disorder (e.g., dyslipidemia or diabetes), it does place the person at higher risk for developing preventable chronic diseases.

Figure 5.8   Dose-response curves for moderate-to-vigorous physical activity and relative risk of type 2 diabetes. The relative risk for type 2 diabetes is significantly reduced with regular bouts of moderate-intensity physical activity. Reprinted from U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee, 2018 Physical Activity Guidelines Advisory Committee Scientific Report (Washington, DC: U.S. Department of Health and Human Services), F5- 24; Cloostermans et al. (2015); Wahid et al. (2016); Huai et al. (2016); Aune et al. (2015).

Can physical activity and exercise be fun while challenging cardiorespiratory and metabolic systems?

Fasting blood glucose concentration is a marker of short-term control of glucose, and the glycosylated hemoglobin concentration is a marker of long-term regulation of glucose (glycosylated hemoglobin is discussed in more detail a little later). Following are three common tests used to diagnose diabetes or prediabetes (they all require at least two tests conducted on separate days):

• Fasting plasma glucose (FPG) test. Blood glucose is measured after an eight-hour fast. If the glucose level is 99 mg/dl or below, the test is normal. A glucose level of 100 to 125 is consistent with prediabetes or impaired fasting glucose; a person with these levels is at higher risk for type 2 diabetes. If the level is 126 or higher, the person has diabetes.

• Oral glucose tolerance test (OGTT). Blood glucose is measured after an eight-hour fast and two hours after ingesting 75 grams of glucose dissolved in water. If the glucose level is 139 mg/dl or below, the test is normal. A glucose level 140 to 199 is consistent with prediabetes or impaired fasting glucose. If the level is 200 or higher, the person has diabetes.

• Random plasma glucose test. Blood glucose is measured (nonfasting) when a person has diabetic symptoms such as increased urination, increased thirst, unexplained weight loss, fatigue, blurred vision, increased hunger, or sores that do not heal. If the glucose level is above 200 mg/dl, the person probably has diabetes.

Many clinicians prefer the FPG test because it is convenient and inexpensive; however, the OGTT is more sensitive for diagnosing prediabetes. Gestational diabetes is also usually diagnosed with the OGTT.

During the 120-day life span of a red blood cell, glucose molecules bind the hemoglobin contained within it, forming glycosylated hemoglobin. Once a hemoglobin molecule is glycosylated, it remains that way its entire life cycle. The percentage of glycosylated hemoglobin reflects the average level of glucose that the cell is exposed to during its life cycle. The species of glycosylated hemoglobin measured clinically and reported is hemoglobinA1c (HbA1c). In healthy people, HbA1c is ~5%. Higher levels of HbA1c (> 6.5%) are found in people with diabetes depending on their average blood glucose. Many guidelines recommend that HbA1c be below 6% for most patients, which corresponds to an average blood glucose of ~126 mg/dl.

GENERAL RECOMMENDATIONS FOR METABOLIC HEALTH Figure 5.9 illustrates the relationship between the risks of having metabolic syndrome and the amount of self-reported physical activity and exercise from several studies evaluating a dose-response relationship (USDHHS, PAGAC 2008). As shown, metabolic syndrome risk drops dramatically with moderate amounts of self- reported physical activity and exercise.

Figure 5.9   Dose-response relationship between self-reported physical activity and the risk of having metabolic syndrome. Reprinted from USDHHS, PAGAC (2008, p. G3-4).

Figure 5.10 illustrates the relationship between developing metabolic syndrome and levels of measured physical fitness from several studies evaluating a dose-response relationship (USDHHS, PAGAC 2008). Metabolic syndrome risk drops dramatically with moderate fitness levels for adults.

Figure 5.10   Risk of developing metabolic syndrome and long-term physical activity levels, shown in four different research studies. Reprinted from USDHHS, PAGAC (2008, p. G3-6).

In 2004, Dr. John Holloszy (a research exercise physiologist and public health professional) of the Washington University School of Medicine reviewed his career work of studying adaptations of skeletal muscle mitochondria for the American College of Sports Medicine (Holloszy 2004). In his review paper, Dr. Holloszy stated his belief that exercise deficiency is a serious public health problem with regard to the development of chronic diseases and the accelerated decline in the function of skeletal muscle, cardiovascular, and metabolic functional capacities with aging. He

further asserted that the most important area of future research is to find effective ways to motivate “couch potatoes” to incorporate regular physical activity and exercise into their daily lives.

Evidence from the landmark Diabetes Prevention Program (2002) supports the lifestyle modification observations of Dr. Holloszy. Adults who were overweight and had prediabetes and who lost 7% of their body weight and were physically active 150 minutes per week reduced their risk for developing diabetes by 58%. The section that follows highlights recommendations from the PAGAC (USDHHS, PAGAC 2008) regarding the integration of physical activity and exercise science to promote metabolic health.

SCIENTIFIC EVIDENCE The 2008 PAGAC reported strong and clear evidence that regular physical activity improves the metabolic health of at least moderately active people by 30 to 40% over that of sedentary people. The benefits of physical activity and exercise on metabolic health apply equally for men and women of all ages, and reasonable evidence supports the association for various racial and ethnic groups.

In 2008, the recommended dose to improve metabolic health was 120 to 150 minutes of moderate- or vigorous-intensity physical activity per week. However, evidence indicated that risk reductions were starting to be seen at levels below 120 minutes per week in people who engage in leisure time physical activity (LTPA). Evidence that resistance training was effective in treating diabetes was limited, although it did improve glucose control. It was noted at that time that more studies were needed to determine whether resistance training can prevent type 2 diabetes. Limited data existed regarding the effects of accumulated daily bouts of physical activity and exercise on metabolic risk, as well as whether physical activity helps control HbA1C or gestational diabetes.

The 2018 PAGAC confirmed the 2008 recommendations and expanded the review of the scientific evidence. The 2018 PAGAC

reported the following with regard to physical activity and type 2 diabetes:

• Strong evidence demonstrates a significant relationship between a higher volume of physical activity and lower incidence of type 2 diabetes.

• Strong evidence demonstrates that an inverse curvilinear dose- response relationship exists between the volume of physical activity and incidence of type 2 diabetes, with a decreasing slope at higher levels of physical activity.

• Moderate evidence indicates no effect modification by weight status. An inverse relationship exists between a higher volume of physical activity and lower incidence of type 2 diabetes for people who have normal weight, overweight, or obesity.

• Limited evidence suggests that the relationship between a higher volume of physical activity and lower incidence of type 2 diabetes is not influenced by age, sex, race, or ethnicity.

• Insufficient evidence is available to determine whether the relationship between physical activity and the incidence of type 2 diabetes varies by socioeconomic status.

• Insufficient evidence is available to determine whether the relationship between physical activity and the incidence of type 2 diabetes varies by the frequency, intensity, duration, or type of physical activity, or how physical activity is measured.

The 2018 PAGAC also studied the scientific evidence regarding bouts of high intensity interval training (HIIT; see chapter 2 for more) and the relationship between cardiovascular risk factors, weight loss, and metabolic profiles. The findings included the following:

• Insufficient evidence is available to determine whether a dose- response relationship exists between the quantity of high-intensity interval training and several risk factors for cardiovascular disease and diabetes.

• Insufficient evidence is available to determine whether the effects of high-intensity interval training on cardiometabolic risk

factors are influenced by age, sex, race, ethnicity, or socioeconomic status.

• Moderate evidence indicates that weight status influences the effectiveness of high-intensity interval training to reduce cardiometabolic disease risk. Adults with overweight or obesity are more responsive than adults with normal weight to high-intensity interval training’s effects on improving insulin sensitivity, blood pressure, and body composition.

GUIDELINES The guidelines for metabolic health are consistent with those for cardiorespiratory health for youth, adults, and older adults. However, people who may have metabolic syndrome or diabetes should take special precautions before undertaking physical activity or exercise programs.

Insulin concentration is an important determinant of the metabolic response to physical activity and exercise. The maintenance of glucose homeostasis is critical for all people, and a normal response to physical activity or exercise depends on exercise FITT (frequency, intensity, time and type) variables, fitness levels, nutritional state, and environmental factors. For those with diabetes, other factors such as the use of insulin or other medications and the temporal relationship to eating are also important to consider during physical activity and exercise.

There are many ways to manipulate the timing and amount of insulin administration and food intake to avoid hypoglycemia or hyperglycemia. It is clear that a reduction in insulin dose in anticipation of exercise decreases the risk of hypoglycemia.

LEADER PROFILE William E. Kraus, MD

Why and how did you get into the field of Physical Activity and Public Health? I have been involved in the exercise and health fields since 1980 when I was in medical school. I became involved in the public health arena for the first time when I was asked to be on the 2008 Physical Activity Guidelines Advisory Committee (PAGAC) in mid-2006.

Did any one person have a major influence on your career? How? Bill Haskell has been an informal career mentor since I first got to know him in 1998. He has been a mentor in the context of my own science: dose-response effects of physical activity and exercise; how to run a guidelines consensus panel in physical activity and public health; and on mentoring in general.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? I have had the benefit of serving on both the 2008 and 2018 Physical Activity Guidelines panels. My interest has always been how to balance public health and medical research. Publishing the findings of the 2018 PAGAC panel in 2019 to increase dissemination of our research was a great achievement for the field. I enjoy presenting at meetings, locally and nationally, and explaining the rationale behind our findings.

Why do you do what you do? I believe the evidence is overwhelming that physical activity is the best medicine and preventive approach for a myriad of human health conditions. I believe the best

thing I can personally do to help my fellow man is to develop further evidence on this topic, share the findings with the wider scientific and lay community, and incorporate these learnings into my own clinical preventive cardiology practice.

What are two key issues that must be addressed by 2030?

1. What is the role of light physical activity on public health?

2. What is the role of step-counting for physical activity monitoring for individuals and public health

recommendations, and can we come to consensus on step-

count recommendations for individual and public

health?

Table 5.3   Clinical Blood Glucose Levels for Active Insulin- Treated Clients

Metabolic control Blood glucose level

Normal blood sugar 80-100 mg/dl

Prediabetic 100-120 mg/dl

High blood sugar (hyperglycemia) >120 mg/dl

Low blood sugar (hypoglycemia) <70 mg/dl

Very low blood sugar (unconsciousness) <40 mg/dl

HbA1C < 7%

More specific recommendations on clinical blood glucose levels are available from the American Diabetes Association (see www.diabetes.org).

People with type 2 diabetes who are not treated with insulin and who do not have extensive vascular or neurological complications can generally exercise with no more concern than nondiabetic people of equal cardiorespiratory fitness. In addition to a preexercise evaluation, blood glucose monitoring should be performed during and after exercise to minimize the risk of developing hypoglycemia.

Added glucose ingestion prior to, during, or after exercise may be a more practical alternative to lowering insulin dose in the prevention

of hypoglycemia. Table 5.3 provides some metabolic control guidelines for people who are active and insulin treated.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

As you previously learned in chapter 2, sedentary behavior and physical inactivity are inconsistent with promoting health for individuals or populations. Current scientific evidence indicates that lack of physical activity impacts all-cause mortality significantly more than sedentary behavior and sedentary activity. Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels that include coronary heart disease (CHD, heart attacks), cerebrovascular disease (stroke), raised blood pressure (hypertension), peripheral artery disease, rheumatic heart disease, congenital heart disease, and heart failure. CVD is the number one preventable cause of death globally. Metabolic syndrome refers to a variety of clinical characteristics that were defined differently in the past by several organizations (e.g., the National Cholesterol Education Program and the WHO). However, most experts now agree that similar profiles are found in adults and adolescents, which include abnormal lipid levels (low high- density lipoprotein [HDL] levels and high triglyceride levels with small, dense low-density lipoprotein [LDL] levels, or atherogenic dyslipidemia), elevated glucose levels, hypertension, and excess abdominal obesity. Research clearly demonstrates the importance of avoiding inactivity. The relative risk of dying prematurely is greatly reduced when one is physically active for 1.5 to 2.5 hours per week versus for only 30 minutes per week.

Personalized plans can be developed to minimize the modifiable and less modifiable risk factors for CVD and metabolic syndrome to ensure future health. The physiological, biomechanical, and psychological benefits of participating in regular physical activity and exercise on cardiorespiratory health are numerous. Determining O2max (or O2peak) and the percentage of O2max (or O2peak) by direct measures or by various estimations can be helpful for evaluating cardiorespiratory fitness or function (CRF). The effective dose of physical activity or exercise for cardiorespiratory health is 800 MET-minutes per week or 12 miles (19.3 km) per week of moderate- or vigorous-intensity activity. The 2018 PAGAC reinforced the findings of the 2008 PAGAC and expanded the review of the scientific evidence. The Physical Activity Guidelines for Americans (USDHHS 2008) state that youth need 60 minutes per day of aerobic physical activity or exercise, and adults and older adults need a minimum of 150 minutes of moderate- and vigorous- intensity activities per week for cardiorespiratory health benefits. Metabolic syndrome affects over 1 billion people globally and represents a major future economic challenge related to the development of diabetes in the United States and the world. The risk factors for CVD and metabolic syndrome are closely related and are positively affected by participation in regular physical activity and exercise. Metabolic function can be evaluated with a standard clinical blood test and other measures such as FPG, OGTT, and HbA1C levels. The effective dose of physical activity or exercise for cardiorespiratory health is 120 to 150 minutes per week of moderate- or vigorous-intensity activity.

The guidelines for metabolic health are consistent with those for cardiorespiratory health, but special precautions may be needed for people who have diabetes and use insulin.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

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Cloostermans L, Wendel-Vos W, Doornbos G, et al. Independent and combined effects of physical activity and body mass index on the development of type 2 diabetes—a meta-analysis of 9 prospective cohort studies. Int J Behav Nutr Phys Act. 2015:147. doi:10.1186/s12966-015-0304-3.

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Ford ES, Kohl HW III, Mokdad AH, Ajani UA. 2005. Sedentary behavior, physical activity, and the metabolic syndrome among U.S. adults. Obesity Research 13 (3): 608-614.

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Mathers CD, Loncar D. 2006. Projections of global mortality and burden of disease from 2002 to 2030. PLoS Med 3 (11): e442.

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Moore SC, Patel AV, Matthews CE. 2012. Leisure time physical activity of moderate to vigorous intensity and mortality: A large pooled cohort analysis. PLoS Med 9 (11): e1001335. doi:10.1371/journal.pmed.1001335.

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U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

Wahid A, Manek N, Nichols M, et al. Quantifying the association between physical activity and cardiovascular disease and diabetes: a systematic review and meta-analysis. J Am Heart Assoc. 2016;5(9). pii:e002495. doi:10.1161/JAHA.115.002495

Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, et al. 2017. ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PC NA guideline for the prevention, detection, evaluation, and

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PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.4.1, 2.1.1, 2.3.3, 2.5.2, 3.1.3, 6.1.3, 6.1.4, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.3.3, 6.3.5, 6.4.1, 6.4.2

CHAPTER 6 Overweight and Obesity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The definitions of overweight and obesity »  The classification of obesity as a disease or a health risk »  Caloric balance and the importance of physical activity

and exercise in achieving it »  The prevalence, economic costs, and risk factors of

overweight and obesity

»  The testing methodologies used to evaluate overweight and obesity

»  Evidence for a relationship between physical activity and energy balance

»  Whether physical activity alone can prevent weight gain, result in weight loss, or keep weight off once it has been lost

»  The impact of sedentary behavior and sedentary activity in relationship to physical activity and weight status

»  The physical activity and exercise recommendations for achieving energy balance and a healthy weight

OPENING QUESTIONS »  What criteria are used to determine whether someone is

overweight or obese?

»  What evidence exists that suggests that physical activity can help with weight maintenance, weight loss, and the prevention of weight regain?

»  How much physical activity is consistent with weight maintenance, weight loss, and the prevention of weight regain?

Other than tobacco use, obesity may be the most discussed and debated public health problem in economically advanced countries. The prevalence of obesity has increased throughout the world; even in countries in which undernutrition has been a recent problem, obesity is starting to take hold. Because it is such a visible condition and because it affects so many people, it has taken a front seat in our health consciousness—perhaps due to its potential health effects, and perhaps for social reasons. Research in this area has exploded; studies related to obesity address issues such as

genetics, behavior, and the environment. What makes someone overweight or obese? Why is this such a problem?

Overweight and obesity have been recognized as major health problems in the United States since 2001 (U.S. Department of Health and Human Services [USDHHS] 2001). The World Health Organization announced that worldwide obesity has nearly tripled since 1975, and that most of the world’s population live in countries in which overweight and obesity kill more people than underweight (WHO 2018). Overweight can be defined as carrying more body fat than is healthy or an amount that increases disease risk. Obesity can be defined as having an unhealthy body weight, which is consistent with a variety of disease processes such as CVD, metabolic syndrome, and type 2 diabetes.

Are overweight and obesity diseases themselves? The answer depends on the definition of disease and which professional organization, government office, corporation, or foundation you consult. Overweight is not considered a disease, but has been associated with numerous health consequences, and although obesity has not been officially recognized as a disease in the United States, private and government insurance groups have been reimbursing people classified as obese by physicians for special foods and weight loss programs and procedures since 2002.

How is obesity individually defined? As it turns out, this is not an easy question because no perfect measure exists. Taller people typically weigh more than shorter people, men typically weigh more than women, and younger people typically weigh more than older people (at a given height). Moreover, statures are different in different cultures across the world. Clearly, body weight is difficult to rely on for a definition of obesity. Later in this chapter, we will review key ways to measure obesity, overweight, and body composition.

Body mass index (BMI) is a frequently used screening measure that takes into account a person’s height as well as weight. The U.S. Centers for Disease Control and Prevention (CDC) advocate the use of BMI as a screening tool to determine the obesity status of adults

and children. To calculate BMI, divide weight in kilograms by height in meters squared:

BMI = weight (kilograms) / height (meters2) Weight, BMI calculations, and classifications of underweight,

healthy weight, overweight, and obese are shown in table 6.1 for adults who are 5 feet 10 inches (178 cm) tall. A standard adult classification indicates those with a BMI between 18.5 kg/m2 and 24.9 kg/m2 are normal weight, and those with a BMI lower than 18.5 kg/m2 are underweight. Adults with a BMI between 25.0 kg/m2 and 29.9 kg/m2 are overweight, and those with a BMI 30 kg/m2 or greater are obese. Above 30 kg/m2, there are several additional classifications: class 1 obesity is 30 to 34.9 kg/m2; class 2 obesity is 35 to 39.9 kg/m2; and class 3 obesity is greater than 40 kg/m2. Currently, adults with class 3 obesity are considered at an extremely high health risk and are generally eligible to be referred for surgical intervention.

Table 6.1   Weight, BMI, and Status for a Sample Height Height Weight range BMI (kg/m2) Status

70 in. (178 cm) <129 lb (58.5 kg) <18.5 Underweight

129-174 lb (58.5-79 kg) 18.5-24.9 Normal

175-208 lb (79.3-94.3 kg) 25.0-29.9 Overweight

>209 lb (94.8 kg) 30 or higher Obese

Although BMI correlates with measures of body composition (e.g., fat percentage, which is discussed later in the chapter), it does not directly measure body composition. BMI measurement does not take into account the specific components of body composition such as lean muscle mass versus fat mass. Therefore, a person with high amounts of lean muscle mass (e.g., an intercollegiate athlete) may be misclassified as being overweight or obese using the BMI. This is a key limitation of using BMI, particularly at the individual level. BMI is not meant to be a clinical diagnostic tool. Rather, it is a useful

screening mechanism and can be helpful in a complete physiological health assessment.

The situation becomes even more complex when dealing with youth. Children and adolescents mature at different rates; some move through growth spurts early in their teens, whereas others mature at a more gradual pace. For this and other reasons, standard BMI definitions for obesity in children and adolescents are different. Instead of a straight set of criteria (as with adults), the definition of overweight and obesity for youth is based on a relative scale.

Standardized growth charts are used to classify children and adolescents based on BMI. Growth charts consist of a set of percentile curves that illustrate various growth trajectories based on a standardized population. Percentiles are relative to a known distribution or population and are used as a standard against which others can be measured. Knowing sex, weight and height, and age, you can use a growth chart to estimate the percentile of BMI. See figures 6.1 and 6.2 for examples of BMI integrated into growth charts. BMI calculators that can calculate youth BMI based on age, sex, height, and weight are available at many websites if you conduct an Internet search for youth BMI. Many adult BMI electronic calculators are also available online.

POPULATION DIFFERENCES Because of observed health risks (CVD and diabetes) in Asian and Pacific populations with BMI values lower than 25 kg/m2, there have been attempts to advance the use of cut points that are different than those developed largely from Western populations. Of basic interest is a division

of the “normal” range (18.50 kg/m2 to 24.9 kg/m2) into two additional levels. Although the World Health Organization (WHO) does not officially endorse these different cut points (due largely to the variability in the scientific evidence), it does indicate that these lower values may be useful to help people of these ethnicities in an advisory capacity. Similarly, the International Diabetes Federation

has provided some general recommendations for clinicians evaluating and identifying metabolic syndrome in various populations, but other professional organizations have noted differences in waist circumference cut points to identify metabolic syndrome in different populations and ethnic groups (Alberti et al. 2009).

Figure 6.1   CDC growth chart and BMI for age percentiles: boys 2-20. National Center for Health Statistics, Health, United States, 2016: With Chartbook on Long- term Trends in Health. Hyattsville, MD. 2017; in collaboration with the National Center for Chronic Disease Prevention and Health Promotion (2000).

Figure 6.2   CDC growth chart and BMI for age percentiles: girls 2-20 National Center for Health Statistics, Health, United States, 2016: With Chartbook on Long- term Trends in Health. Hyattsville, MD. 2017; in collaboration with the National Center for Chronic Disease Prevention and Health Promotion (2000).

Following is a generally accepted classification scheme for BMI and weight status in children and adolescents:

Underweight: BMI less than the 5th percentile for age and sex Healthy weight: BMI between the 5th and 85th percentiles for age and sex Overweight: BMI between the 85th and 95th percentiles for age and sex

Obese: BMI greater than the 95th percentile for age and sex

CALORIC BALANCE As discussed in chapters 2 and 4, a basic understanding of energy expenditure is essential for determining how physical activity and exercise can positively affect overweight, obesity, and the achievement of a healthy weight. Although the focus of this text is on energy expenditure to achieve caloric balance, energy intake (i.e., the food you eat) is clearly important as well.

A simple caloric balance equation scale is shown in figure 6.3. For weight loss, all that is required is to create an energy deficit by consuming fewer calories (i.e., eating less), expending more calories (i.e., being more physically active), or both. Sounds pretty easy. However, on further inspection (and in real life), it is clear that achieving and maintaining energy balance is a complex state that some people never attain—and many cycle in and out of energy balance throughout their lives.

The 2015-2020 Dietary Guidelines for Americans (USDHHS, USDA 2015-2020) provides important guidance on energy intake for weight maintenance. For energy expenditure related to weight control, guidance can be found in the two editions of Physical Activity Guidelines for Americans (USDHHS 2008, 2018). These three references provide information about the variables in figure 6.3 such as behavioral, social, cultural, and environmental factors and how they affect caloric expenditure or increased energy storage.

The increase in the prevalence of overweight and obesity in children and adults worldwide clearly indicates that simple solutions for weight control are not working for a vast majority of people. And, although caloric restriction (i.e., dieting) alone can result in short- term weight loss and management, long-term solutions require physical activity increases and the maintenance of energy expenditure for most to obtain and maintain a healthy weight as well as to achieve other health benefits.

Figure 6.3   Energy balance equation. Please review chapter 4 for discussion of the thermic effect of food (TEF), basal metabolic energy expenditure (BMEE), and physical activity energy expenditure (PAEE).

Have you ever thought about how many kilocalories (kcals) you expend per day in physical activity or exercise and how that expenditure affects your body weight and body composition? Although the energy cost of various physical activities (see part I) is known, how can we determine how many calories (kcals) we need to expend, individually or collectively, for effective weight management? Following is an important equation that we can use to answer this question:

1 lb (0.45 kg) of fat = 3,500 kcals Therefore, to lose 1 pound (0.45 kg) of fat, theoretically, you would

need to restrict or maintain your energy intake while expending more kcals in physical activity and exercise to the equivalent of 3,500 kcals. This is not a perfect match because all the while you are breathing, you are burning calories—albeit much more slowly than if you were exercising. A good rule of thumb is that, assuming a caloric intake of 2,500 to 3,000 kcals a day, burning 400 to 500 kcals each day through physical activity, for many people, would be a useful contribution to the maintenance of a healthy weight. For normal weight people, this can be the rough equivalent of walking about 3 miles (4.8 km) each day at a moderately intense pace.

Body composition is defined as the relative proportion and distribution of fat, lean mass (muscle and bone), and minerals in the body. An important outcome of participating in regular physical activity and exercise is that you can maintain or increase lean body mass while controlling body fat levels (i.e., have a healthy body composition), whereas with dietary-only interventions, lean mass is not maintained.

Estimates of weekly physical activity and exercise caloric expenditure levels, or physical activity energy expenditure (PAEE; see chapter 4), for healthy adults with varying levels of physical activity and exercise behaviors are shown in table 6.2.

The values in table 6.2 are based on data from table 2.4 in chapter 2, which shows that by simply meeting the minimum guideline for physical activity, substantially more kcals are expended (940 versus 190 at rest) by walking at 4 miles per hour (6.4 km/h) for 150 minutes per week than by remaining sedentary. Jogging at 7 miles per hour (11.3 km/h) for 300 minutes per week, to use another example, will burn 3,930 kcals above sedentary levels, which is the energy equivalent of more than 1 pound (0.45 kg) of fat (USDHHS, Physical Activity Guidelines Advisory Committee [PAGAC] 2008).

People starting a physical activity or exercise program should try to achieve caloric balance by adjusting their food intake based on

their new energy expenditure levels and weight management goals. Some people may need to set their physical activity and exercise levels above recommended levels to expend enough energy to achieve or maintain a healthy weight. Older adults also need to consider that basal metabolic energy expenditure (BMEE) drops with age, making weight management more challenging and physical activity and exercise even more important for weight management.

PREVALENCE OF OBESITY AND OVERWEIGHT AND ASSOCIATED HEALTH CONSEQUENCES As noted, the prevalence of obesity and overweight has increased dramatically since the mid-20th century. Although anthropological studies have shown that human populations have been gaining weight (on average) for centuries (due largely to improved nutrition), the tipping point from weight gain to obesity has been only a recent phenomenon.

Table 6.2   Expenditure Estimates (PAEE) by Duration and Intensity of Physical Activity

Duration of Physical Activity

Type of physical activity 150 min/wk (2.5 hr/wk) 300 min/wk (5.0 hr/wk)

Sedentary – sitting at rest 190 kcals 380 kcals

Walking (4 mph/6.4 km/h) 940 kcals 1,880 kcals

Jogging or running (7 mph/11.3 km/h)

2,155 kcals 4,310 kcals

Based on a 165 lb (75 kg) adult.

In the United States, the CDC (National Center for Health Statistics 2017) reported that over 70.7% of people over the age of 20 were overweight or obese. The WHO (2018) estimated in 2016 that at least 1.9 billion adults over age 18 are overweight, and 650 million throughout the world are obese. Because the human genotype is resistant to short-term changes, it is clear that the global and U.S. trends of increasing obesity are primarily due to external

changes (e.g., changes in the built environment and lifestyle factors). Figure 6.4 shows the obesity trends among adults from the CDC Behavioral Risk Factor Surveillance System for 1994, 2000, and 2015 (USDHHS, CDC 2018).

Figure 6.4   Obesity trends among U.S. adults. Reprinted from National Health Examination Surveys II (ages 6-11) and III (ages 12-17); National Health and Nutrition Examination Surveys (NHANES) I-III; NHANES 1999-2000, 2001-2002, 2003-2004, 2005-20063, 2007-2008, 2009-2010, 2011-2012, and 2013-2014.

The trend of an increasing prevalence of overweight and obesity among children and adolescents over the past 45 years is also disturbing. Obesity trends among children and adolescents from 1963 to 2014 (from the CDC’s National Health and Nutrition Examination Survey data, National Institute of Diabetes and Digestive and Kidney Diseases 2017) are shown in figure 6.5. In the United States at least 18.5% of youth between the ages of 2 and 19 years are obese. Among children ages 2 to 5 years, the prevalence of obesity has increased to 13.9%; among children ages 6 to 11 years, it has increased to 18.4%; and among adolescents ages 12 to 19, it has increased to 20.6%.

Preventing childhood overweight and obesity is very challenging. Research has demonstrated that obese youth may be more likely to become obese adults than youth who are not obese. This situation increases the risk of chronic, noncommunicable diseases such as hypertension, high cholesterol, and type 2 diabetes.

The CDC (2009) and others have reported that the prevalence of obesity and overweight varies significantly among U.S. adults, adolescents, and children based on racial and ethnic differences. For

example, the CDC reports that non-Hispanic blacks had a 22% greater prevalence of obesity and Hispanics had a 25.8% greater prevalence, compared to non-Hispanic whites. The results varied somewhat by state, but were consistent across the United States. These findings support the important goals of the U.S. health promotion initiative Healthy People 2020 (USDHHS 2011), which include reducing the prevalence of obesity in adults in the United States to 30.5% from 33.9% baseline (in 2005-2008) and eliminating health disparities among racial and ethnic populations that contribute to obesity and overweight.

Interestingly, Wang and colleagues (2008) reported that if the current U.S. overweight and obesity trends continue, by 2030, 86.3% of adults would be overweight or obese, and 51.1% would be obese. They also reported that African American women and Mexican American men would be the subgroups most affected with rates of 96.9% and 91.1%, respectively. The authors projected that by 2048, all American adults would be overweight or obese, and African American women would reach that level by 2030 if trends continue as they are. For children and adolescents, the prevalence of obesity (>95th percentile) will almost double by 2030 to about 30% overall.

The economic costs of overweight and obesity in the United States vary considerably based on how they are categorized and estimated. Obesity and overweight either directly contribute to the development of costly chronic disease processes, or they complicate the medical treatments associated with managing the diseases once diagnosed (or both). The estimated total costs for the United States in 1998 may have been as high as $78.5 billion (Finkelstein, Fiebelkorn, and Wang 2003), which included medical expenses for both overweight and obesity. The economic costs (estimated at $81.5 billion in 2010) of obesity and overweight were predicted to double every decade until 2030 and to eventually cost $860 to $956 billion per year, which would account for 15.8 to 17.6% of total U.S. health care costs (Wang et al. 2008).

Figure 6.5   Obesity trends among U.S. children and adolescents. Reprinted from National Health Examination Surveys II (ages 6-11) and III (ages 12-17); National Health and Nutrition Examination Surveys (NHANES) I-III; NHANES 1999-2000, 2001-2002, 2003-2004, 2005-20063, 2007-2008, 2009-2010, 2011-2012, and 2013-2014.

Data from Chenoweth and Leutzinger (2006) are illustrated in figure 6.6 and provide an example of the continuing economic costs of physical inactivity and excess body weight. The authors analyzed the combined economic costs that physical inactivity and excess weight had on the U.S. economy in 2003 and the projected costs in 2004 through 2008 with regard to direct medical care, workers’ compensation, and productivity loss. If medical costs had continued to rise as they had (10.2% per year), along with workers’ compensation increases (4.5% per year) and productivity loss increases (4.1%), and if levels of physical inactivity and excess weight prevalence had stayed the same, the projected total costs would have exceeded $708 billion in 2008. The work by Chenoweth and Leutzinger (2006) presented conservative estimates of the actual economic costs and reflects the increasing costs associated with the current trends of physical inactivity and excess body weight.

Figure 6.6   Trends in economic costs due to physical inactivity and excess weight. Reprinted by permission from D. Chenoweth and J. Leutzinger, 2006, “The Economic Cost of Physical Inactivity and Excess Weight in American Adults,” Journal of Physical Activity and Health 3, no. 3 (2006): 148-163.

OBESITY AND OVERWEIGHT RISK FACTORS The risk factors for obesity and overweight are complex and difficult to understand because there is not just one cause. The risk factors for obesity are related to behavior, the environment, genetic factors, and their interactions. We all know very thin people who don’t exercise at all and people who are obese or overweight who report exercising frequently. The cause of obesity in two people is rarely the same, and the cause(s) across populations vary in the same way.

HEALTH CONSEQUENCES OF OBESITY The health consequences of obesity and overweight include the following physical, psychological, and social challenges for adults, adolescents, and children:

Coronary heart disease (CHD)

Type 2 diabetes

Cancers of the endometrium, breast, and colon

Hypertension

Dyslipidemia (high total cholesterol, or high levels

of triglycerides)

Stroke

Liver and gallbladder disease

Sleep apnea and respiratory problems

Osteoarthritis

Gynecological problems (abnormal menses, infertility)

Source: 22 August 2015, www.cdc.gov/healthyweight/effects/index.html

A variety of factors that influence the caloric balance equation can cause people to eat too many calories, to not get enough regular physical activity or exercise, or both, resulting in energy imbalance and weight gain. The environment at home, school, work, and in the community can provide numerous barriers and incentives that affect the ability to achieve caloric balance and maintain a healthy weight. Genetics may predispose people to weight gain or obesity, but the lifestyles they adopt can help them achieve caloric balance and a healthy weight based on their body type and body composition (see Common Assessments of Obesity and Overweight later in the chapter for more). Modifiable Risk Factors for Overweight and Obesity

Physical inactivity Excess caloric intake Low socioeconomic status (SES)

Nonmodifiable Risk Factors for Overweight and Obesity

Age Heredity (genetics) Ethnicity or race Culture

Metabolism

Following are descriptions of the modifiable and nonmodifiable risk factors for overweight and obesity:

• Physical inactivity. Inactivity creates a health cost versus a health benefit, and physical activity helps most people achieve energy balance. Increased levels of physical activity and exercise have been shown to improve long-term weight maintenance and enhance weight loss. Energy expenditure opportunities in modern society have been reduced as a result of technological advances and environmental barriers. Examples include watching TV (more than two hours a day) and excessive media use such as texting and surfing the Internet.

• Excess caloric intake. When energy intake exceeds energy expenditure, weight gain occurs.

• Age. Obesity and overweight problems increase for many as they age because of the difficulty of achieving caloric balance while dealing with the physical and mental challenges of normal aging. People who are homebound or living alone may be especially susceptible to weight gain.

• Heredity. Genes can affect factors such as metabolism, which can predispose a person to obesity or overweight, but research shows that people can adjust their lifestyles and achieve caloric balance and a healthy weight despite hereditary challenges.

• Race and ethnicity. Different race and ethnic groups have varying prevalences of obesity. However, scientific studies have not revealed whether the differences are due to genetic determinants or to social or cultural disparities.

• Socioeconomic status (SES). SES can provide major challenges to acquiring a healthy diet and to finding safe, affordable opportunities for engaging in physical activity or exercise.

• Culture. Cultural traditions (e.g., the built environment) and behaviors can provide a variety of challenges to making positive lifestyle changes to achieve caloric balance and a healthy weight.

• Metabolism. A person’s resting metabolism (i.e., the rate of caloric expenditure at rest) can be affected by a variety of factors including genetics, physical activity, diet, age, and medications.

OBESITY AND OVERWEIGHT CHALLENGES Physical activity and exercise can affect energy balance related to common obesity and overweight challenges such as weight loss, healthy weight maintenance, the prevention of weight regain, and excessive abdominal fat. Clinically significant weight loss has been defined as at least a 5% loss of body weight (USDHHS, PAGAC 2008). Weight maintenance (or weight stability) has been defined as a weight change of less than 3%, and prevention of weight regain after a substantial loss that is consistent with a change in weight of 3% to less than 5%. The 2018 PAGAC reviewed recent evidence for obesity and overweight challenges, and while the definition for clinically significant weight loss remains the same, a couple of updated terms and definitions were suggested: Body weight status is a concept encompassing issues related to weight gain, loss, and maintenance, and excessive weight gain is a change in body weight of more than 2 kg per year or 10 kg per decade; or, a weight increase of more than 3%.

Fat is stored throughout the body. It can be found around the organs (visceral fat) or near the skin (subcutaneous fat). Some people seem to store fat preferentially in one location over others. Men, for example, are more likely to store fat in the abdominal region (also called male pattern fat distribution), whereas women are more likely to store fat in the hips, buttocks, and legs. Increased abdominal fat is associated with metabolic disorders including metabolic syndrome (see chapter 5 for more on metabolic syndrome and physical activity) more so than female pattern fat distribution. Research shows that abdominal fat loss is associated with increased levels of physical activity and is proportional to overall fat loss.

Engaging in regular physical activity and exercise, in and of itself, is not a panacea for losing weight, maintaining a healthy weight,

preventing weight regain, or decreasing abdominal fat. As described earlier, many other factors influence caloric balance besides physical activity and exercise. Four points to help people achieve energy balance are (1) the concept of total energy intake; (2) intervening with physical activity and exercise alone, diet only, or a combination of diet and physical activity and exercise; (3) how nonactive leisure time activities compete with active pursuits; and (4) the benefits of engaging in regular physical activity and exercise other than just preventing obesity and overweight.

Excessive energy intake has become a way of life because of the availability of inexpensive, high-calorie foods that taste good. The trend of overconsumption correlates highly with the prevalence of obesity and overweight; therefore, all weight management strategies should address diet. Numerous excellent resources that focus on healthy eating can be found at www.nutrition.gov.

Physical activity and exercise are associated with caloric expenditure, but these strategies used alone for weight loss, weight maintenance, or the prevention of weight regain are not as effective as when they are combined with diet (energy intake) interventions. Figure 6.7 illustrates weight loss related to a diet intervention (caloric reduction), an exercise intervention, and a diet plus exercise intervention. As you can see, physical activity and exercise are not sufficient for providing clinically significant weight loss. Figure 6.8 illustrates the differences in BMI values between active and less active people; it suggests a dose-response relationship between physical activity and exercise and BMI, supporting the recommendations of the 2018 PAGAC, which encourages adults to participate in 150 minutes or more of moderate- to vigorous-intensity physical activity per week.

Figure 6.7   Weight loss related to a diet intervention, an exercise intervention, and a diet plus exercise intervention. Reprinted from USDHHS, PAGA (2008).

Figure 6.8   Differences in BMI values due to level of physical activity. Reprinted from USDHHS and PAGAC (2008, p. G4-7); adapted from Kavouras et al. (2007).

KINESIOLOGY AND BODY WEIGHT Children, adolescents, and adults can experience the positive exercise-related adaptations associated with regular participation in physical activity and exercise that can help with weight loss, healthy weight maintenance, the prevention of weight regain, and the loss of excessive abdominal fat. The combined benefits of physical activity and exercise listed in the highlight box Adaptations to Fitness Programming Related to Body Composition can help various populations improve their health and quality of life.

COUNSELING FOR WEIGHT MANAGEMENT Efforts to increase caloric expenditure with physical activity and exercise can be impeded with competition from

all of today’s labor-saving attractions (computers, cell phones, and other electronic media) that impede active discretionary time activities. Strategies to help people optimize the leisure time they spend being active can be helpful. Good advice would be: Choose the active choice!

Physiologically, participation in regular physical activity can help people lose weight and achieve a healthy weight, or get closer to achieving caloric balance. These basic changes can lead to increases in muscular endurance and O2max levels, which result in improved functional health (i.e., people can do more work before fatiguing).

Physical activity and exercise can also help people reduce total body fat, waist circumference, and intra-abdominal fat; maintain or increase lean muscle mass; and prevent the regaining of weight lost. Ultimately, participation in physical activity and exercise can lower the risks for such chronic disease processes as type 2 diabetes, metabolic syndrome, and CHD, as well as orthopedic challenges associated with obesity and overweight.

Although the associations are not well understood at this time, overweight and obesity are often linked with multiple factors that negatively affect restful sleep. For example, people who suffer from obstructive sleep apnea (OSA), restless leg syndrome (RLS), and insomnia and who become physically active experience reduced symptoms. Numerous studies have shown that physical activity and exercise are associated with increases in sleep duration and quality of sleep (especially delta sleep). These sleep improvements can help people get a good night’s rest and be active and ready to go the next day without the usual chronic fatigue associated with problems such as OSA. The loss of upper abdominal fat, which can be achieved by becoming physically active, is also associated with reduced respiratory problems such as OSA.

ADAPTATIONS TO FITNESS PROGRAMMING RELATED TO BODY COMPOSITION Physiological

Increased muscular endurance

Increased O2max Improved caloric balance

Improved metabolism

Lower percentage of body fat

Smaller waist circumference

Less intra-abdominal fat

Maintenance of or increased lean muscle mass

Maintenance of or loss of weight

Biomechanical

Improved economy

Improved balance

Improved mobility

Improved proprioception

Behavioral

Increased self-confidence

Improved self-efficacy

Decreased depression and anxiety

Increased motor skill

Experience with behavioral change and increased

confidence to engage further in physical activity and

exercise

Biomechanically, improved economy of movement can be expected with weight loss and the maintenance of a healthy weight. Improved economy of movement is a function of improved efficiency,

which is directly related to body weight and body composition, particularly in weight-bearing activities. Losing weight or achieving weight stability can allow people to perform motor skills more efficiently as a result of increases in range of motion, which is limited by carrying excess weight or body fat. Improved biomechanical function also inspires confidence to engage in future physical activity and exercise activities. Peripheral proprioception (i.e., sense of position and movement) response, which is associated with balance and fall prevention, often improves as well.

Weight loss and weight stability also have strong psychological effects. Experiencing the unique challenges of the phases of behavioral change (contemplation, preparation, action, maintenance, relapse) gives people coping skills and strategies for achieving and maintaining a healthy weight. In addition, people who have lost weight or succeeded at maintaining a healthy weight experience more self-confidence, greater feelings of self-efficacy, and lower levels of depression and anxiety.

COMMON ASSESSMENTS OF OBESITY AND OVERWEIGHT Common assessments of obesity and overweight provide estimated body composition values such as the percentage of body fat, lean muscle mass, and total body fat. Everyone needs some fat to maintain normal bodily functions. Essential fat is important for stored energy, cushioning and insulation, and vitamin absorption; it is found in and around the nervous system, heart, lungs, kidneys, spleen, intestines, and muscles. The minimal amount of essential fat for men has been estimated to be 3% of body weight; for women the estimate is around 12% of body weight. When essential body fat falls too low, health risks for chronic disease and adverse immune reactions increase.

Ideal body fat and ideal body weight are terms that have been used to describe the hypothetical optimal percentage of body fat or body weight. The values for ideal body fat and ideal body weight, however, are highly variable and should be based on factors such as

age, sex, personal goals, behaviors, and appropriate educational messaging that does not promote addictive disorders (i.e., eating or exercise). However, most men are considered obese if they are carrying ≥28% body fat, and most women, if they are carrying ≥32% (Jackson and Ross 1997).

The simplest way to assess body composition is visual inspection. If one’s BMI (discussed earlier) is already higher than normal and there is weight gain and no regular physical activity and exercise, that person is probably carrying too much body fat. Although many of us have noticed visually that we were gaining weight and were therefore motivated to try to lose weight, we did not have quantitative data (e.g., percentage of body fat, amount of lean muscle mass) to help us set goals and gauge our success. Body composition assessments, described next, provide the quantitative information necessary for setting weight management goals and evaluating program outcomes.

The highlight box Common Methods for Measuring Body Composition lists laboratory-based and field tests that exercise scientists use to measure body composition. See figure 6.9 for photos illustrating skinfold testing and dual-energy X-ray absorptiometry.

Magnetic resonance imaging (MRI) and computed tomography (CT) are currently recognized as the gold standard (or best available with minimal error) techniques for measuring body composition. However, because of the expense of these techniques (about $1,000 USD per scan, or $1,000,000 USD for the purchase of a scanning device), they are mainly used in research and as medical diagnostic tools. Both of these techniques rely on X-ray technology to quantify the amount of fat tissue and other tissue in the body or in a region of the body. MRI is thought to be a safer technique largely because it does not rely on ionizing radiation.

Dual-energy X-ray absorptiometry (DXA) full body scans are more affordable than MRIs and CTs, but the device can be expensive. Many exercise physiologists now regularly use DXA in

the assessment of body composition. Scanning is done while a person is still and supine on a table; X-ray beams are emitted and data are differentiated into fat mass, fat-free mass, and skeletal (bone) mass in a two-dimensional display. The DXA technique can provide precise data about a person’s percentage of body fat, as well as bone mineral density data. The DXA technique usually has an error of about 1% compared to MRI and CT measures for full body scanning, but it can be less accurate if the scan does not include the whole body.

Figure 6.9   Body composition measures: (a) skinfold testing and (b) dual- energy X-ray absorptiometry.

Underwater (or hydrostatic) weighing is based on the principle of water displacement (i.e., when you get in tub of water, the water level rises based on the volume your body displaces). In this technique, a person’s weight is measured both in and out of water. A person with more fat (which is less dense than lean body tissue) will be buoyed up more than a leaner person, and will consequently weigh less underwater. To minimize measurement errors, hydrostatic weighing requires motivated subjects and additional laboratory equipment that can be used to measure residual lung volume (RV). If RV is estimated (as is often done) and not measured, large errors in measurement can result. A hydrostatic tank system costs about $10,000 to $15,000 USD and requires regular maintenance. Hydrostatic weighing used to be considered the gold standard for body composition measurements and has been traditionally used,

but the technique has a measurement error of 2 to 3% compared to MRI, CT, and DXA.

Air displacement plethysmography (i.e., the measurement of change in volume) determines volume and density, and has become a popular technique used at universities and by many sport teams. A common tool for this technique is the commercially available BOD POD. This technique, based on the same displacement principles as hydrostatic weighing, uses multiple sensors in the measurement unit to measure air displacement in a known period of time. Body fat is then calculated based on those data. Air displacement plethysmography is relatively easy to use, but the devices are expensive (about $35,000 USD) and not readily available. Compared to the MRI, CT, and DXA techniques, this technique has about a 3% measurement error.

Skinfold measurement has been used by exercise scientists and clinicians for many years to estimate body composition based on population-specific and generalized equations. Measuring skinfold thickness at various sites on the body (e.g., the tricep, abdomen, and thigh) provides an estimate of subcutaneous fat (about 50% of total body fat) and therefore an estimate of body density and the percentage of body fat. Using the equations developed by Jackson and Pollock (1978, 1980), the percentage of body fat can be estimated from the sum of skinfold thickness, age, and sex. Skinfold calculators can be found at websites such as www.exrx.net. Skinfold measurements correlate well with hydrostatic weighing measures, but have at least a 3% error rate.

COMMON METHODS FOR MEASURING BODY COMPOSITION

Visual inspection

BMI

Magnetic resonance imaging (MRI); computed tomography

(CT); dual-energy X-ray absorptiometry (DXA)

Hydrostatic weighing

Air plethysmography

Skinfold measurement

Bioelectrical impedance analysis (BIA)

Circumferences (waist and hip)

Bioelectrical impedance analysis (BIA) sends a low-amperage electrical current through surface electrodes on the body (e.g., the wrist and ankle). Measurements of the resistance to the current permit the estimation of body composition using prediction equations. Tissues of different densities conduct electricity at different rates, and thus body composition can be estimated. The BIA technique can be highly variable based on the following factors:

Quality of the BIA instrument used Fluid balance (normal hydration or dehydration) of the subject Recent food consumption Effects of recent bouts of physical activity and exercise

The cost of BIA instruments ranges from $100 to several thousand dollars (USD); the more expensive models provide better measures when subjects’ hydration levels are controlled (about 3% error rate). Some simple BIA instruments (e.g., bathroom scales) predict the percentage of body fat based on BMI, but they have about a 6% error rate.

Waist circumference measures have become common ways to determine when people are carrying too much abdominal fat for good health. For waist circumference, it is generally recommended to measure girth at the level of the lowest rib or umbilicus level using a cloth measuring tape with a spring-loaded handle that costs about $15 to $20 USD. Waist circumferences are measured in inches or

centimeters. Adults should have waist measures of ≤40 inches (102 cm) for men, and ≤35 inches (89 cm) for women (Kenney, Wilmore, and Costill 2015).

Waist circumference values for children and adolescents (ages 2 to 18 years) have been published (Fernandez et al. 2004) and are expressed as percentile ratings by age, sex, and ethnicity (African American, European American, and Mexican American). Youth can be classified by waist girth as being in the 10th through 90th percentile. Although there is no professional consensus on an ideal waist circumference measure for youth because of growth and development issues, it is reasonable to encourage youth to maintain a girth close to the 50th percentile.

Waist circumferences can be used in combination with youth BMI measures to clarify higher-than-expected BMI measures (e.g., in athletic youth with high levels of muscle mass). For example, if a youngster has a high BMI and a high waist measurement (>90th percentile), she should not be encouraged to gain more weight. A youngster with a low BMI (<5th percentile for age and sex) and low waist measurement should not be encouraged to lose more weight.

The waist-to-hip ratio (WHR) is another simple way to use circumferences to evaluate the distribution of body fat in adults. Health risk increases as WHR increases, and standards vary by age and sex. According to the guidelines of the American College of Sports Medicine (ACSM 2018), young adult men and women should have ratios of lower than 0.95 and 0.86, respectively, to be categorized as having a low health risk. Older adult men and women (ages 60 to 69 years) should have ratios of lower than 1.03 and 0.90, respectively, to be classified as having a low health risk.

PHYSICAL ACTIVITY GUIDELINES FOR A HEALTHY WEIGHT For many adults, obesity is associated with significant increases in abdominal fat that increase the risk for metabolic syndrome and type 2 diabetes (see chapter 5). Regular participation in aerobic physical activity and exercise can decrease total body fat and abdominal fat,

and these changes are consistent with improved metabolic function. Generally, the greater the volume of physical activity or exercise acquired by individuals or populations, the greater the reductions in body and abdominal fat.

For children and adolescents, the prevention of excessive weight gain during maturation is critical to prevent obesity and overweight in adulthood. Unfortunately, recent public health surveys note that the parents of many at-risk children are not aware of the problem or do not recognize that their children are overweight. Recent U.S. national policy statements targeting pediatricians and other health care providers assert that children and adolescents who are overweight or obese in their early teens should be identified as early as possible and given some sort of weight management plan through the intervention of parents, teachers, coaches, and family physicians.

One of the most obvious influences on weight management is how people perceive their ideal weight or physique. Research findings indicate a great disparity between reasonable weight loss or weight gain goals and people’s “dream weight.” Even though some people may not reach their goal weight, they will likely report positive physical, social, and psychological benefits from any weight loss. The following scientific evidence and guidelines can help individuals and populations establish realistic goals for weight management (e.g., achieving a healthy weight) and meet their specific needs (e.g., weight loss, weight stability, prevention of weight regain, or loss of excessive abdominal fat) through regular participation in physical activity and exercise.

SCIENTIFIC EVIDENCE The 2008 PAGAC noted physical activity (150 minutes per week to ≥300 minutes per week) was associated with modest weight loss, prevention of weight gain following weight loss, and reductions in total and regional adiposity. Evidence that resistance training helped with weight maintenance was not as strong, given that resistance

training increases lean muscle mass, and the volume of resistance training regimes was usually less than that for aerobic training.

Can a walking program be effective for weight management without diet control?

The 2018 PAGAC expanded the review of the evidence available in 2008, and focused on weight maintenance and weight gain within normal BMI limits (18.5 to < 25 kg/m2) for adults in relation to participating in 150 minutes per week or more of physical activity. The 2018 report also reviewed the impact of sedentary behavior and sedentary activity in relationship to physical activity and weight status. The specific 2018 PAGAC findings regarding weight gain were:

Strong evidence demonstrates that the significant relationship between greater time spent in physical activity (≥300 minutes per week) and attenuated weight gain in adults is observed with moderate-to-vigorous physical activity. Moderate evidence indicates that the relationship between greater amounts of physical activity and attenuated weight gain in adults does not appear to vary by sex.

Limited evidence suggests a dose-response relationship between physical activity and the risk of weight gain in adults, with greater amounts of physical activity (150 minutes per week) associated with lower risk of weight gain. Limited evidence suggests that the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by age, with the effect diminishing with increasing age. The evidence from studies of older adults, however, is inconsistent. Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by race and ethnicity. Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by socioeconomic status. Insufficient evidence is available to determine whether the relationship between greater amounts of physical activity and attenuated weight gain in adults varies by initial weight status. Insufficient evidence is available to determine an association between light-intensity activity and attenuated weight gain in adults.

The 2018 PAGAC concluded the following with regard to the impact of sedentary behavior and sedentary activity for adults in relationship to physical activity and weight status:

Limited evidence suggests a positive relationship between greater time spent in sedentary behavior and higher levels of adiposity and indicators of weight status. Limited evidence suggests the existence of a direct, graded dose-response relationship between greater sedentary behavior and higher levels of adiposity and indicators of weight status. Insufficient evidence is available to determine whether the relationship between sedentary behavior and weight status

varies by age, sex, ethnicity, socioeconomic status, or baseline weight status. Insufficient evidence is available to determine whether the relationship between sedentary behavior and weight status varies by amount of moderate-to-vigorous physical activity. Insufficient evidence is available to determine whether bouts or breaks in sedentary behavior are important factors in the relationship between sedentary behavior and weight status.

As mentioned earlier in the chapter, regular physical activity and exercise are also important to prevent and control obesity and overweight in children and adolescents. The 2008 PAGAC found strong evidence demonstrating that higher levels of physical activity were associated with multiple beneficial health outcomes, including cardiorespiratory and muscular fitness, bone health, and maintenance of healthy weight status in children and adolescents (ages 6-19). The 2018 PAGAC focused on expanding the review of literature since 2008 with the addition of studies on children 3-6 years of age. The additional scientific recommendations of the 2018 PAGAC for youth were as follows:

Strong evidence demonstrates that higher amounts of physical activity are associated with a reduced risk of excessive increases in body weight and adiposity in children ages 3 to 6 years. Limited evidence suggests that greater time spent in sedentary behavior is related to higher weight status or adiposity in children and adolescents; the evidence is somewhat stronger for television viewing or screen time than for total sedentary time. Insufficient evidence is available to determine whether the relationship between physical activity and health effects in children younger than 6 years of age is moderated by age, sex, race, ethnicity, weight status, or socioeconomic status.

GUIDELINES

The physical activity guidelines for youth and adults regarding weight control are the same as for other health outcomes with one notable exception. The guidelines recommend that preschool-aged children (ages 3 through 6 years) should be physically active throughout the day to enhance growth and development, and adult caregivers of preschool-aged children should encourage active play that includes a variety of activity types. Children and adolescents should participate in 60 minutes of moderate- or vigorous-intensity physical activity daily to maintain a healthy weight. Adults (and older adults) who are trying to control their weight should include dietary considerations, and they should follow the 2015-2020 Dietary Guidelines for Americans to learn more about weight management and how to determine a healthy weight. Many adults will achieve caloric balance and lose weight if they meet the minimal physical activity and exercise guidelines of acquiring 150 minutes per week of moderate-intensity physical activity, 75 minutes per week of vigorous-intensity physical activity, or a combination of both, and two days of bone-strengthening and muscle-strengthening activities.

LEADER PROFILE Adriano Akira Hino, PhD

Why and how did you get into the field of Physical Activity and Public Health? I have practiced judo since I was 9 years old, so physical activity and sport were part of my childhood and adolescence. It was not hard to figure out that I wanted to be a physical education professor. I don’t know exactly what made me take the track of Public Health, but I think it was a natural progression from my personal interests and my curiosity. I always wanted to understand behaviors, and epidemiology gave me the perfect tool to do it. Since I started working with epidemiology, Public Health has made sense.

Did any one person have a major influence on your career? How? Definitively yes. I have had the opportunity to work with very good researchers since I was an undergrad student, so my path is filled with professors who had a huge influence on my career. There is not enough space to mention all their names; however, I need to acknowledge Ciro Rodriguez-Añez, Rodrigo Reis, and Olga Lucia Sarmiento who were especially important to my career. They taught me everything I know today and gave me the chance to work on high-level research projects and to meet the most important researchers in the field. These teachings and opportunities were key components that led me to where I am today, professionally and personally.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? I have two main interests at this moment in my career. The first one is to better understand how the environment can affect physical activity. The second one is to better understand how evidence can be used during the decision- making process. We already have evidence of interventions that work to promote physical education, but they haven’t been enough to increase physical activity levels. Thus, dissemination and implementation is an area that I will invest considerable time working on during the upcoming years.

Why do you do what you do?

I believe it is because my work can have an impact on people’s health.

What are two key issues that must be addressed by 2030? In terms of physical activity and considering the context of my country (Brazil), I would say that reducing physical activity inequalities is a key issue that must be addressed by 2030. The second issue is the importance of including evidence-based research in the decision-making process of health and physical activity promotion. This would bring the researchers and the decision makers closer together and increase the likelihood of more effective interventions.

Given the effect of body weight on both energy expenditure and energy intake, the minimal physical activity guidelines may not be enough in some cases to create an energy deficit or balance. Thus, for weight control, 150 minutes per week of moderate-intensity physical activity, 75 minutes per week of vigorous-intensity physical activity, or a combination of both, should be step one. Adults who want to lose a substantial amount of weight (more than 5% of body weight) and those who are trying to maintain their weight after a significant weight loss may need to do more than 300 minutes per week of moderate-intensity activity to meet weight-control goals.

Older adults may have physical disabilities that limit the intensity at which they can engage in physical activity and exercise, making weight loss more of a challenge than it is for younger adults. The physical activity guidelines stress that older adults (as well as youth and adults 18 to 65) should remember that caloric expenditure results from engaging in all types of physical activities, and not just exercise. For example, taking short walks throughout the day and making active choices such as taking the stairs instead of the elevator expends calories and can be helpful in weight control as compared to remaining sedentary. Older adults who can engage in vigorous physical activity or exercise may find that this strategy is more effective (time efficient) for weight control than working at

lower-intensity activities for more time. In any case, older adults should try to participate in regular physical activity and exercise that is sustainable and safe.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

A basic understanding of energy expenditure and caloric balance is essential for a more detailed understanding of the relationships between exercise and physical activity, and overweight and obesity. BMI is a common measure to classify adults and youth as obese, overweight, normal weight, or underweight. The prevalence of obesity and overweight is at pandemic levels in the United States and globally for youth and adults. By 2030, if obesity prevalence levels in the United States do not change, the economic costs will reach 15.8 to 17.6% of total U.S. health care costs. The health consequences of obesity include CHD, type 2 diabetes, cancer, hypertension, dyslipidemia, stroke, liver and gallbladder disease, sleep apnea and respiratory problems, osteoarthritis, and gynecological problems. The environments at home, school, work, and in the community provide numerous barriers and incentives to achieve caloric balance and maintain a healthy weight. Genetics may increase the predisposition for weight gain or obesity, but a healthy lifestyle can help people achieve caloric balance. Physical activity and exercise are associated with caloric expenditure, but using these strategies alone for weight loss, healthy weight maintenance, or the prevention of weight

regain is not as effective as combining them with diet (i.e., energy intake) interventions. The physiological, biomechanical, and psychological benefits of participating in physical activity and exercise on obesity and overweight are numerous and achievable for most people. Common laboratory-based and field tests used to measure body composition are visual inspection, BMI, MRI, CT, DXA, hydrostatic weighing, air plethysmography, skinfold measurement, BIA, waist circumference, and waist-to-hip ratios. Engaging in regular moderate- to vigorous-intensity physical activity for more than 150 minutes per week can help many adults achieve energy balance, weight loss, weight maintenance, and the prevention of weight regain after weight loss, as well as reduce abdominal fat. However, some people may require more activity (≥300 minutes). Positive changes in youth body composition have been associated with at least 30 minutes per day of regular moderate- to vigorous-intensity physical activity. Everyone should try to follow the recommendations in the Physical Activity Guidelines for Americans to achieve and maintain a healthy weight.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

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Fernandez JR, Redden DT, Pietrobelli A, Allison DB. 2004. Waist circumference percentiles in nationally representative sample of African-American, European-American, and Mexican- American children and adolescents. Journal of Pediatrics 145: 439-444.

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Kavouras SA, Panagiotakos DB, Pitsavous C, Chrysohoou C, Anastasiou CA, Lentzas Y, Stefanadis C. 2007. Physical activity, obesity status, and glycemic control: The ATTICA study. Medicine & Science in Sports & Exercise 39 (4): 606- 611.

Kenney WL, Wilmore JH, Costill DL. 2015. Physiology of Sport and Exercise, 6th ed. Champaign, IL: Human Kinetics.

Morbidity and Mortality Weekly Report (MMWR). 2009. Differences in prevalence of obesity among Black, White, and Hispanic adults—United States, 2006-2008. Morbidity and Mortality Weekly Report (MMWR) 58: 740-744.

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U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

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U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. 2011. Healthy People 2020. www.healthypeople.gov/2020. Accessed 12 August 2011.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

U.S. Department of Health and Human Services, U.S. Department of Agriculture. 2015-2020 Dietary Guidelines for Americans, 8th ed. Washington, DC: U.S. Government Printing Office.

Wang Y, Beydoun MA, Liang L, Caballero B, Kumanyika SK. 2008. Will all Americans become overweight or obese? Estimating the progression and cost of the U.S. obesity epidemic. Obesity 16: 2323-2330.

Wing, RR. 1999. Physical activity in the treatment of the adulthood overweight and obesity: Current evidence and research issues. Medicine and Science in Sports and Exercise 31 (suppl 11): S547-S552.

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overweight. Accessed 17 August 2018.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

2.2.3, 2.3.2, 2.5.1, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.4, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.5.2, 6.53

CHAPTER 7 Musculoskeletal and Functional Health

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The prevalence of musculoskeletal disorders and related health challenges

»  The physical challenges associated with low levels of musculoskeletal fitness, as well as common testing methodologies to assess musculoskeletal fitness

»  How physical activity affects bone, joint, muscle mass, and muscle function in relationship to musculoskeletal health

»  How physical activity can influence functional and role ability

»  How exercise adaptations positively influence functional health

»  The physical activity guidelines for promoting physical activity related to functional health, and the evidence behind them

OPENING QUESTIONS »  Can exercise improve the strength and quality of bone tissue? »  Why is muscle quantity (muscle mass) and muscle quality

(muscle function) important for good health?

»  How much physical activity is needed for good musculoskeletal health?

»  What is functional health? How can functional health be improved to reduce the risks for physical disabilities?

Have you ever watched a grandparent, aunt, or other older relative struggle to rise from a sitting to a standing position because of a lack of upper body strength? Have you ever watched (or been) a child who was not selected for an athletic team or pickup game for lack of strength? Do you want to be able to enjoy life, be as independent as possible, and do all the things you want without physical limitations into old age? Each of these questions directly relates to the human musculoskeletal system (i.e., bones, muscles, joints, and connective tissue) and its ability to help us do the physical things we want to do.

Although much of the scientific and popular attention on physical activity and health has (appropriately) focused on how exercise helps the cardiovascular and metabolic systems (see chapter 5), we are learning that the benefits to the musculoskeletal system are just as important. Scientific evidence clearly supports the importance of maintaining physical activity as we age to optimize physiological

capacity, minimize physiological limitations, maintain functional and role ability, and reduce the risks of falls (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2008, 2018). This chapter introduces these topics and presents the scientific rationale for engaging in physical activity for musculoskeletal health.

PREVALENCE OF MUSCULOSKELETAL DISORDERS AND RELATED HEALTH CHALLENGES The most common musculoskeletal disorders that result from low physical activity levels are osteoporosis (bone health), osteoarthritis (joint health), and low levels of the quantity and quality of muscle mass. Osteoporosis (low bone mass and structural deterioration of bone tissue) is estimated to be a public health threat to 44 million Americans, or 55% of those over 50 years of age (National Osteoporosis Foundation 2010). Clearly established diagnostic criteria for osteoporosis exist: People with a bone mineral density (BMD) below the normal range have the disease. Women are much more likely than men to have osteoporosis. Of the 10 million people estimated to have osteoporosis in the United States in 2010, approximately 80% were women and 20% were men.

Why is osteoporosis a problem? Most important, osteoporosis and low bone mineral density (BMD) contribute to increased bone fracture risk including fractures of the hip, vertebral column, and wrist. The risk of falling is increasingly a problem as we age, and low BMD can accelerate the risk of fractures that are either spontaneous or secondary to a fall. In 2005, the National Osteoporosis Foundation reported that osteoporosis was related to more than 2 million fractures in the United States in the following categories:

Hip: 297,000 Vertebrae: 547,000 Wrist: 397,000 Pelvis: 135,000

Other sites: 675,000

Due primarily to the aging of the U.S. population, the incidence of bone fractures resulting from osteoporosis and low BMD is expected to increase by a million more cases by 2025, which will contribute to lower quality of life, higher disease management costs, and increased mortality for those affected. The economic cost of osteoporosis and low BMD associated with osteoporosis-related fractures was $19 billion (USD) in 2005, and has been predicted to affect 3 million people at a cost of $25 billion by 2025.

Although there are several types of arthritis, osteoarthritis (OA) is the most common form of joint disease and is associated with joint pain and dysfunction along with irreversible loss of articular cartilage. Osteoarthritis is often thought of as a mechanical joint disease affecting primarily the weight-bearing joints (knees and hips). Clinically, OA symptoms include joint pain, swelling, stiffness, and weakness. The development of OA is associated with increased disability and lifestyle challenges.

Approximately 27 million U.S. adults (or ~12% of the U.S. population) are affected by this most common form of arthritis, and it is also the fifth leading cause of disability. To put this into perspective, California is the only state in the United States (according to the 2010 U.S. Census) with more than 27 million people! Women are affected with OA more than men are, especially related to the knee. By the year 2030, it has been predicted that 67 million people, or 25% of the U.S. population, will suffer from OA.

The economic costs of OA are difficult to estimate because it is often reported medically as a musculoskeletal condition, and not differentiated from other disease processes. Moreover, falls and fractures can occur in the absence of OA. Many of the economic costs of OA are work related (i.e., absenteeism and presenteeism, terms used in the workplace to define decreased on-the-job performance as a result of health problems). In 2007, U.S. costs were estimated at more than $185 billion per year including

physician office visits, hospital and outpatient treatments, medication use, diagnostic tests, and other related medical treatments (Kotlarz et al. 2009). Obviously, for those who have OA and require arthroscopic surgery, joint replacement surgery, or reconstruction, the costs can accumulate rapidly.

RISK FACTORS ASSOCIATED WITH MUSCULOSKELETAL DISORDERS AND ASSOCIATED HEALTH CHALLENGES Chapter 5 highlighted the major risk factors for cardiovascular disease (CVD) and diabetes. Although a complete review of all the risk factors associated with low levels of musculoskeletal health and poor functional health is beyond the scope of this text, we will review the risk factors associated with the musculoskeletal health challenges of osteoporosis, osteoarthritis, and low levels of the quantity and quality of muscle mass. As you might have guessed already, many, but not all, musculoskeletal health challenges are associated with sedentary lifestyles or low levels of physical activity.

OSTEOPOROSIS According to the U.S. National Osteoporosis Foundation (2010), there is an extensive list of risk factors associated with the development of osteoporosis. As with CVD and diabetes mellitus, these factors can be grouped into modifiable and nonmodifiable factors. Modifiable Risk Factors for Osteoporosis

Physical inactivity Tobacco use Being thin or underweight Alcohol abuse Low sex hormone (estrogen or testosterone) levels Low calcium or vitamin D intake or absorption Excessive caffeine intake

Nonmodifiable Risk Factors for Osteoporosis

Age Sex Heredity (genetics) Ethnicity or race History of fractures

Following are descriptions of the modifiable and nonmodifiable risk factors for osteoporosis:

• Physical inactivity. People who are physically inactive are less likely to have optimal bone mineral density (BMD) than their more active peers.

• Tobacco use. Smokers reduce their ability to absorb calcium, which is important for good bone health, and smoking also tends to interfere with estrogen and bone protection.

• Being thin or underweight. Being underweight is associated with small bone structure and less weight and force on bones, and may be associated with poor nutrient intake or eating disorders.

• Age. Advancing age (men >70 years, women >50 years and postmenopause) is associated with increased osteoporosis risk because of physiological changes associated with aging and bone loss.

• Sex. Women are at a higher risk for osteoporosis than men at an earlier age; however, men with lower testosterone or estrogen levels, or both, are also at increased risk.

• Nutrition. Low calcium and vitamin D intake and availability are risk factors for osteoporosis. Excessive alcohol and caffeine intake have also been implicated.

• Heredity (genetics). A family history of osteoporosis can increase the risk for developing the condition.

• Ethnicity or race. Evidence suggests that some groups have lower rates of osteoporosis than others (e.g., African Americans

have lower rates than American Caucasians, Asians, or Latinos). • Low estrogen or testosterone levels. Normal levels of sex

hormones, by sex, (i.e., estrogen and testosterone) help protect bone; therefore, women who are postmenopausal, women with amenorrhea (i.e., are not menstruating regularly), and some men with lower testosterone levels may be at higher risk for osteoporosis.

• History of fractures. A history of fractures in adulthood may indicate that the person already has osteoporosis.

STRENGTH TRAINING AND FRAIL OLDER ADULTS Strength training was once thought to be too dangerous and unproductive for frail older adults. A landmark study by Dr. Maria Fiatarone and her colleagues at Tufts University (Fiatarone et al. 1994) was quick to disprove that notion. In this study, 100 nursing home residents who averaged 87.3 years of age were randomized to a weight training or a nonexercise control group for a 10-week period. Muscular strength and muscle mass were measured before and after the study. Not only did the training significantly improve muscular strength in those who did the strength training, but muscle mass increased (2.7%) as well. The outcomes were much better in the strength training group than in the group that received dietary supplements alone (nonexercise). This study helped change many preconceptions about strength training and older adults.

OSTEOARTHRITIS Osteoarthritis (OA) is one of many forms of arthritis characterized by excessive (and lasting) stiffness and swelling in the joints. Unlike other forms of arthritis, OA is thought to result from abnormal stresses on the joints. According to the U.S. National Arthritis Foundation (2011), the primary risk factors associated with the development of OA are age, obesity, injury or overuse, genetics or

heredity, and muscle weakness. Not surprisingly, some risk factors for OA can be modified, whereas others cannot. Modifiable Risk Factors for OA

Physical inactivity Excessive physical activity, or overuse Excess body mass

Nonmodifiable Risk Factors for OA

Age Sex Heredity (genetics) History of joint injury

Following are descriptions of the modifiable and nonmodifiable risk factors for osteoarthritis:

• Physical inactivity. Physical inactivity is a two-edged sword when it comes to OA. Some physical activity is associated with a lower risk of OA, whereas too much provides excessive joint stress and may increase the risk. Physical activity helps increase muscular strength, which is important for supporting joints (e.g., strong quadriceps for the knee joint).

• Excessive physical activity. Too much physical activity, or a history of athletic overtraining (i.e., excessive exercise that produces negative effects) is associated with an increased risk of OA. Some sports and recreational activities have been found to be associated with the development of OA.

• Excess body mass. Overweight (i.e., high BMI) is associated with higher rates of OA. This is thought to also be related to joint overload.

• Age. Joints degenerate over time. This natural degeneration may be compounded by previous joint injury history, excessive physical activity or exercise, or both.

• Sex. Women are at a higher risk than men for most types of OA, which is probably due in part to lower levels of quadriceps strength on average as compared with males, which can influence OA development in the hips or knees.

• Heredity (genetics). A family history of OA may predispose a person to developing OA.

• History of joint injury. Previous joint injuries associated with weight-bearing movement (especially at the knee) increase the risk for developing OA.

• Occupational load. Some occupations require workers to carry heavy loads and this form of overuse may contribute to OA risk.

LOW MUSCLE MASS Musculoskeletal health is not necessarily linked to a specific disease process. Low muscle mass (also known as sarcopenia) is thought to be an important determinant of functional health, particularly among older adults. Therefore, this section reviews selected factors that are associated with low levels of functional health, specifically falls, which correlate with low levels of muscle mass quantity and quality. According to the Physical Activity Guidelines Advisory Committee (USDHHS, PAGAC 2008), the three primary risk factors associated with low levels of functional health are aerobic capacity, muscular strength, and balance. Following are the major modifiable and nonmodifiable risk factors for low muscle mass, as well as other potential risks. Modifiable Risk Factors for Low Muscle Mass

Physical inactivity Tobacco use

Nonmodifiable Risk Factors for Low Muscle Mass

Age Sex

Heredity (genetics)

Following are descriptions of the modifiable and nonmodifiable risk factors for low muscle mass:

• Physical inactivity. Physical inactivity is associated with lower muscle mass, particularly in aging, frail people. The “use it or lose it” principle is highly appropriate here.

• Age. Although aging is inevitable, the quantity and quality of muscle mass and aerobic capacity in most people can be maintained at high levels well past the age of 65, if they maintain a normal BMI (18.5 to 25), remain physically active, and do not smoke.

• Sex. Women, on average, have a lower muscle mass than men do, so it is even more important that they become physically active (in their youth) and remain so throughout their lives.

• Genetics (heredity). Functional health depends on genetics; however, practicing positive behaviors such as being physically active, maintaining a healthy weight, and minimizing risky activities can increase the quantity and quality of muscle mass.

KINESIOLOGY AND MUSCULOSKELETAL HEALTH Musculoskeletal function has been repeatedly demonstrated to improve from engaging in activities such as strength and resistance training. Even with moderate-intensity physical activity, most people see improvements in strength (muscle mass quantity) and muscular endurance (muscle mass quality related to function). One does not necessarily need to lift weights to see musculoskeletal benefits; other activities such as working with resistance bands, doing calisthenics (push-ups, pull-ups, sit-ups), carrying heavy loads, climbing stairs, and heavy gardening (digging and hoeing) are also associated with positive changes in strength and muscular endurance. Older sedentary adults can see improvements of 50 to 100% in certain measures of strength and muscular endurance (e.g., hand grip and leg extension and flexion) in 8 to 12 weeks.

MUSCULOSKELETAL ADAPTATIONS TO PHYSICAL ACTIVITY AND EXERCISE Physiological

Increased muscular strength: Ability to move more weight

Increased muscular endurance: Ability to sustain muscular contractions over time

Increased O2max: Increased aerobic capacity Increased muscle force and power: Increased amount of force generated by the muscle when contracting,

remaining static, or elongating

Increased muscle fiber size: Skeletal muscle hypertrophy can occur with or without measurable gains in strength.

Improved neural recruitment: Recruitment of more nerves to stimulate muscle contraction

Increases in anaerobic enzymes: Increases in compounds that can use fuel without the need for oxygen

Increased anaerobic energy stores: Increased ability to store fuel when needed for high power output

Improved hormone-mediated bone remodeling: Increases in bone matrix and mineral turnover

Improved connective tissue function: Improved ability of tissues to connect, bind, support, and anchor the

body

No change, or increase, in BMD: No change or increase in bone quality

Maintenance of, or increase in, lean muscle mass:

Increase in total muscle

Maintenance or loss of weight: Weight loss even with an increase in muscle tissue

Biomechanical

Improved economy: Ability to move more efficiently Improved balance: Maintenance of even weight distribution to prevent falling

Improved mobility: Increased range of motion of muscles and connective tissue around joints

Increased motor skill function: Improved communication between the brain and muscles for smoother, more

efficient operation

Improved proprioception: Improved ability of the body to sense movement and space; helps in movement and

balance

Behavioral

Increased self-esteem and self-confidence: Improved satisfaction with or confidence in oneself,

particularly related to physical activity and

exercise

Improved self-efficacy: Improved attitudes, abilities, and cognitive skills, particularly related to

physical activity and exercise

Decreased depression and anxiety: Less moodiness, despondency, nervousness, unease, and worry

The highlight box Musculoskeletal Adaptations to Physical Activity and Exercise contains some of the long-term exercise-related adaptations acquired by engaging in muscle-strengthening activities, which can positively influence musculoskeletal health. The amount of physiological adaptation related to each of the benefits is dose dependent, meaning that low doses yield lower results and fewer changes than do higher doses. Chapter 2 discusses physical training principles in more detail.

Although cardiorespiratory adaptations (see chapter 5) to musculoskeletal strengthening activities are less than those seen with aerobic (cardiorespiratory) physical activities, sedentary people can increase their O2max (or O2peak) from 5 to 8% with resistance training. Those who engage in circuit training, a form of interval training using resistance training and aerobic exercise (see chapter 2 for more), often increase their O2max (or O2peak) by approximately 5% (Gettman and Pollock 1981).

Increases in the rate of force (strength) development and power (time rate of work) are observed over time during physical activity and resistance training. Musculoskeletal strengthening results in the ability to recruit more motor units (the nerve and the fibers it controls), increased individual muscle fiber size (fast and slow twitch), increased numbers of anaerobic enzymes, and higher amounts of anaerobic energy stores. All of these factors are important for performing high-intensity, short-duration musculoskeletal activity.

Connective tissue changes associated with the specific muscles used during musculoskeletal strengthening activities may include increases in ligament strength, tendon strength, and collagen content. Resistance training can also cause positive hormonal changes (e.g., up-regulation of anabolic hormone receptors) that allow for the remodeling of bone. Further, resistance activities can increase bone mass (or BMD) in some people, or may at least delay bone mass loss in people at risk for osteoporosis.

Exercise physiology research has clearly shown that regular participation in physical activity and musculoskeletal strengthening increases lean muscle mass (quantity and quality) and reduces body fat, thereby helping with weight management. Figures 7.1 through 7.3 illustrate common changes in musculoskeletal fitness or function after physical activity or exercise training.

Figure 7.1   Motor units (i.e., the nerve plus the muscle fibers it controls) that include slow-twitch fibers (aerobic) and fast-twitch fibers (anaerobic) and the relationship between force production and motor unit recruitment. Physical activity and exercise improve the ability to increase the recruitment of motor units and therefore improve force production. Reprinted by permission from D. French, “Adaptations to Anaerobic Training Programs,” in Essentials of Strength Training and Conditioning, 4th ed., edited for the National Strength and Conditioning Association by G.G. Haff and N.T. Triplett (Champaign, IL: Human Kinetics, 2016), 91.

Biomechanically, improved economy or efficiency (i.e., reduced energy cost at a given workload) can be expected after musculoskeletal strengthening. For elderly people, this may mean simple yet important improvements in day-to-day activities. Balance and stability are often improved by engaging in resistance training activities. Improved mobility (flexibility and range of motion) and motor skills obtained through strengthening activities can give people the confidence to engage in future physical activity and exercise activities. Their peripheral proprioception (i.e., sense of position and movement) response often improves as well.

Figure 7.2   Bone remodeling, progressing from left to right, in response to mechanical loading such as that from participating in regular physical activity and exercise.

Behaviorally, people often feel better and have more self- confidence after several weeks of participation in physical activity that includes resistance activities. Some evidence suggests that people who participate in muscle-strengthening and resistance training activities experience lower levels of depression and anxiety, and they also probably experience higher self-efficacy (i.e., a sense of personal accomplishment and well-being) levels.

COMMON TESTS OF MUSCULOSKELETAL FITNESS OR FUNCTION Many tests have been developed over the years to evaluate musculoskeletal fitness and function. Some are fairly easy to use, whereas others require a laboratory and medical personnel. Field tests, which can be done fairly easily and with large numbers of people, may not be as accurate as clinical ones. A familiarity with some of the common tests of musculoskeletal fitness or function (and the interpretation of their results) will help with the following:

Establishing baseline levels of strength and muscular endurance Understanding the strengths and weaknesses of the scientific literature in this area Determining the extent of disabilities or limitations that can influence the ability to engage in physical activity and exercise Developing a plan for including regular musculoskeletal strengthening activities in an overall physical activity program Understanding the need to seek musculoskeletal rehabilitation or medical advice

Figure 7.3   Relative responses of physiological variables to training and detraining (see chapter 2). Reprinted by permission from S.J. Fleck and W.J. Kraemer, Designing Resistance Training Programs, 4th ed. (Champaign, IL: Human Kinetics, 2014), 298.

The websites listed in the web resource and the references at the end of this chapter provide more comprehensive information on musculoskeletal fitness and function tests, and how to successfully

administer and interpret them. This section provides a brief overview of the most common muscle and bone assessments.

A list of assessments for strength, muscular endurance, power, balance, gait, mobility, and bone strength can be found in the highlight box Assessments of Musculoskeletal Fitness or Function. The discussion that follows briefly describes the assessments and how they might be used clinically. Several commercial websites offer free performance evaluation calculators (see the e-Media section at the end of this chapter).

Muscular strength is essentially the ability of a muscle or set of muscles to generate adequate force to move a predetermined weight. People with weightlifting experience often perform muscular strength testing with free weights or machine weights. The very common 1-repetition maximum (1RM) test indicates how much a person can lift one time; 1RM can be determined for several muscle groups (e.g., arms, legs, chest) and is a useful indicator of overall muscular strength. The 1RM value is easy to use when developing a muscle-strengthening plan. People without weightlifting experience or who have safety issues can perform other lifts such as a 5RM or a 10RM, and their 1RM can be estimated from their performance on these lifts (see Baechle and Earle 2008).

Handgrip dynamometry is a simple static method of assessing grip strength using commercially available devices; it is correlated to other measures of static strength. Isokinetic dynamometry is a test of dynamic strength in which the subject performs an exercise through a range of motion at a constant speed. Because isokinetic testing requires expensive equipment, it is most often performed in clinical and rehabilitation settings. Photos of some common tests of musculoskeletal fitness or function are shown in figure 7.4.

Contrary to muscular strength, muscular endurance refers to the ability of a muscle or set of muscles to repeatedly generate a submaximal force (perform repeated contractions) or to sustain a contraction for a period of time. Muscular endurance testing can also be performed using free weights or machine weights (once 1RM has

been established) by lifting a weight that is a percentage of 1RM (e.g., 70%) as many times as possible. The percentage of 1RM used to determine muscular endurance varies based on the person being tested.

ASSESSMENTS OF MUSCULOSKELETAL FITNESS OR FUNCTION

Strength: 1RM, 5RM, 10RM, handgrip dynamometry,

isokinetic dynamometry

Muscular endurance: Number of lifts using 70% of 1RM,

push-ups, pull-ups, sit-ups, sit-to-stand tests,

sport-specific tests

Power: Wingate anaerobic power test, standing long

jump, vertical jump

Balance: One-leg stand, gait speed, Berg balance

scale

Gait: Get-up-and-go, curve course walk

Mobility: Goniometer test

Bone strength: DXA, ultrasound

Simple and common weight-bearing muscular endurance tests such as push-up, pull-up, and sit-up (or curl-up) tests are traditional assessments of muscular endurance, and specific protocols exist for testing various populations. Sit-to-stand tests (e.g., the number of repetitions someone can complete in 30 seconds) for evaluating the muscular endurance of the elderly can be found in the research and clinical literature. Sport-specific tests for higher-fit people that assess muscular endurance are also readily available (see the websites listed in the e-Media section).

Figure 7.4   Musculoskeletal fitness and function may be assessed in many ways, including (a) handgrip dynamometry, (b) 1RM, and (c) the vertical jump.

Measuring power in younger people is usually easier than in older people because of the need for explosive effort (>95%). The Wingate anaerobic power test can be used in laboratory settings to determine maximal and average muscular power. Traditional power tests such as the standing long jump and vertical jump can provide simple measures of power that are easily interpreted.

Balance assessments are primarily for older people who may be at higher risk for falls (i.e., have low functional health), people who are in physical rehabilitation programs (e.g., physical therapy), and athletes who are striving for high levels of performance (e.g., dancers, gymnasts, martial artists). The one-leg stand is a balance test that can be performed with the eyes open or closed; the time the person can stand in the proper position is recorded. Gait speed on a straight or curved course can be used to determine the balance abilities of elderly people. The Berg balance scale is a functional test that provides a composite balance score of 14 items for evaluation of the elderly.

Gait assessments are also used primarily for older people to evaluate their functional health. Common tests related to gait analysis are the get-up-and-go assessment and various curved walking course assessments.

Numerous mobility (flexibility and range of motion) tests have been developed to evaluate people of all ages. Perhaps the most common assessment of mobility is goniometry, which involves

having a professional (e.g., a physical therapist or exercise physiologist) measure joint angles, movement limitations, or both.

The only sure way to assess bone mineral content is to surgically remove a piece of bone (by making an incision or inserting a needle into a bone close to the skin’s surface) and analyzing it in a laboratory. This is obviously a painful procedure; it is most frequently done to diagnose bone diseases such as cancer. Technological advancements have resulted in the development of BMD screening tools that are quite accurate, painless, and fairly low cost. Bone strength screening and assessment are common clinical and medical assessments and best accomplished with the use of dual- energy X-ray absorptiometry (DXA). DXA is the most valid and reliable screening measure for BMD. Other techniques such as ultrasound (i.e., sound waves) are available, but currently are less accurate than DXA.

Figure 7.5 illustrates the relationship between BMD and aging, as well as a strategy (i.e., increased physical activity including musculoskeletal activities) to prevent or delay osteoporosis by increasing peak bone mass in youth. The figure shows normal BMD loss with aging in a healthy, inactive individual and the increases and maintenance of higher levels of BMD for a healthy, physically active individual with aging. Peak bone mass (or BMD) occurs on average for men and women by age 30 and begins to drop after menopause in women, and by age 70 in most men. Teenage girls, as a population, are an excellent target group to encourage regular participation in musculoskeletal (as well as other physical activity and exercise) activities throughout life, because they should be able to increase their peak bone mass. This, at least theoretically, might delay the point at which they would develop osteoporosis or experience negative musculoskeletal symptoms or disabilities.

Figure 7.5   Schematic illustration of a strategy to prevent or delay the onset of osteoporosis by increasing peak bone mass during youth. Reprinted by permission from C.J.R. Blimkie and O. Bar-Or, New Horizons in Pediatric Exercise Science (Champaign, IL: Human Kinetics, 1995), 78.

PHYSICAL ACTIVITY AND MUSCULOSKELETAL HEALTH Although extensive research documents the benefits of resistance training, particularly for athletic competition, only since the early 1980s has this evidence been developed enough to make specific recommendations for engaging in musculoskeletal activities. Historically, it was thought that the only purpose of the skeletal system was to provide structure for muscles; its role in physical activity and exercise was considered minimal. We obviously now know that the skeletal system is a living organ that can change substantially based on external stimuli, such as physical activity. Similarly, the connective tissues of muscles, tendons, and ligaments, as well as weight-bearing bones, have been found to become thicker and develop greater tensile strength in response to dynamic exercise training. In addition, bones’ response to resistance exercise has

been to become thicker and stronger regardless of their weight- bearing function. That is, the benefits are not all due to the constant bearing of body weight: Bone health can be improved through physical activity.

SCIENTIFIC EVIDENCE There is moderate scientific evidence of an inverse relationship between physical activity and exercise and the risk of hip fractures in adults (USDHHS, PAGAC 2008). The evidence of a relationship between physical activity and the risk of vertebral fractures exists, but it is not as strong as that for hip fractures. There is no direct evidence that regular moderate-intensity physical activity promotes the development of OA. Participation in low or moderate levels of physical activity may protect against the development of OA, whereas participation in moderate-intensity, low-impact physical activity has been shown to decrease pain and increase function, quality of life, and mental health in people with OA, rheumatoid arthritis, and fibromyalgia (i.e., overall muscular pain and aching). The current evidence that physical activity delays the onset of disability from OA is weak.

Much of what we know about the effects of physical activity and exercise on bone health includes information not on activity but on inactivity. Studies have looked at BMD and bone mineral content (BMC) in astronauts who have spent multiple weeks or months in space with zero gravity and thus no force on their skeletal systems. These studies consistently show that people subjected to these environments (1) show measurable bone loss that is not uniformly distributed across the skeleton, (2) absorb vitamin D and calcium (two micronutrients important for bone strength) less efficiently, and (3) need much more time to rebuild the lost bone than it took to lose it. Other studies have specifically looked at the effects of several days or weeks of complete bed rest on physiological factors like O2max. In the study results shown in figure 7.6, fitter (trained) individuals actually had greater decrements with inactivity (20 days

of bed rest) than less fit (sedentary) individuals, and the fitter individuals required 55 days to regain their baseline fitness levels. Clearly, these conditions can accelerate the risk of osteoporosis, osteoporotic fractures, or both.

Figure 7.6   The effects of 20 days of bed rest and 55 days of retraining on O2max for five individuals.

Adapted by permission from B. Saltin, “Response to Submaximal and Maximal Exercise After Bed Rest and Training,” Circulation 38, no. 7 (1968): 75.

Although the scientific evidence is never as strong as we want it to be, existing studies show fairly consistently that participation in regular physical activity and exercise can reduce the risk of hip fractures anywhere from 36 to 68%, and regular physical activity can increase BMD consistently by 1 to 2%. These data are based on short-term exercise training studies, most of which have been less than one year in duration. For this reason, the exact benefits of a lifetime of physical activity participation are unknown. Further, benefits of physical activity on BMD have been found for premenopausal women, menopausal women, and adult men.

What about physical activity for people who already have OA? Does it help? There is fairly strong evidence that people of any age with preexisting OA seem to benefit from aerobic and resistance exercise. Muscular strength improves, as does BMD. Women with OA may benefit more than men from resistance training because they likely have lower baseline strength levels. General muscular

strength benefits of physical activity are similar for men and women across the life span, although they diminish with older age. Information on the benefits of physical activity on the bone and general muscular health of people of various races or ethnicities is lacking.

How much physical activity is necessary? The effective dose of physical activity and exercise for musculoskeletal health varies depending on the desired outcome (bone, joint, or muscle health). For bone health (depending on the study), four hours of walking per week, 2 to 4 hours of moderate- or vigorous-intensity physical activity each week, and one hour of weekly physical activity have each been associated with a 36 to 41% reduction in the risk of hip fracture. Weight-bearing endurance and resistance physical activity of moderate intensity three to five days per week for 30 to 60 minutes per session increases BMD. Walking-only protocols may improve spinal BMD (moderate evidence of bone changes).

Evidence strongly suggests an association between physical activity and relief from pain in people with arthritis. The suggested dose of physical activity and exercise for adults with arthritis (to reduce pain and disability and increase function) is 130 to 150 minutes per week of moderate-intensity, low-impact activity; experts suggest 30 to 60 minutes per session, three to five days per week. Both aerobic and muscle-strengthening activities improve joint function and reduce pain. Progressive, high-intensity (60 to 80% of 1RM) muscle-strengthening activities can preserve or increase skeletal muscle mass, power, and intrinsic neuromuscular activation.

The effects of an accumulation of physical activity and exercise throughout the day on musculoskeletal health have not been tested, or research is limited. The scientific evidence from randomized controlled trials and laboratory animal studies has shown the intensity of loading forces to be the key determinant for skeletal response. Joint injuries and carrying excess body mass are more important risk factors for OA than sport participation. Finally, endurance types of physical activity do not increase muscle mass,

but they may slow the rate of muscle mass loss with aging, while preserving function.

GUIDELINES Resistance training and the options available related to muscle- strengthening activities were discussed earlier in the chapter. This section contains the Physical Activity Guidelines for Americans recommendations in lay terms. The guidelines for musculoskeletal health have been divided into three parts: children and adolescents (ages 6 to 17), adults (ages 18 to 64), and older adults (>65 years).

Like aerobic activities (see chapter 2), muscle-strengthening activities should be based on the dose-response concept—or in this case, intensity, frequency, and repetitions. Following are definitions related to resistance training:

Intensity: How much weight or force is lifted or used relative to how much a person is able to lift or exert Frequency: How often (expressed usually per week) a person does muscle-strengthening activities Repetitions: How many times a person lifts a weight in a given set and how many sets the person performs (related to rest between reps and sets, or groups of repetitions)

The benefits of muscle-strengthening activities are limited to the muscle groups that are worked. Therefore, people need to work the major muscle groups, which include the legs, hips, back, abdomen, chest, shoulders, and arms.

Bone-strengthening activities can include both aerobic and muscle-strengthening activities, because both promote growth and strength, particularly compared to sedentary living. Bone- strengthening activities include jumping jacks, running, brisk walking, and weightlifting. Any weight-bearing activity can count as a bone- strengthening activity—even stair climbing.

Children and adolescents should participate in muscle- strengthening activities at least three days per week, as part of the

overall recommendation of 60 minutes or more of physical activity and exercise per day. They should also participate in bone- strengthening activities at least three days per week, as part of the same overall recommendation. Table 7.1 contains specific examples of muscle-strengthening and bone-strengthening activities for children and adolescents, as well as for adults and older adults. As shown, children and adolescents do not need to engage in formal resistance training to acquire musculoskeletal benefits. Adults and older adults should engage in muscle-strengthening activities involving all major muscle groups at moderately to vigorously intense levels at least twice per week to see improvements in muscular strength and endurance.

No specific number of repetitions has been recommended for resistance training, but people should perform to the point at which performing another repetition without help would be difficult. Resistance training involving one set of 8 to 12 repetitions using several muscle groups has increased strength, although performing two or three sets, with the appropriate amount of rest between sets, may be more effective. Muscular strength and endurance changes occur progressively over time, and increases in the amount of weight, frequency, or both, can result in greater changes.

Adults and older adults may benefit from engaging in warm-up (prior to physical activity bout) and cool-down (after physical activity bout) activities that include muscle-strengthening activities. These activities slowly increase the blood flow to the working muscles, thereby helping to deliver fuel and take away metabolic waste. Adults and older adults may also benefit from performing flexibility activities (e.g., stretching), although no scientific evidence documents health benefits related to stretching, and stretching does not seem to reduce the risk of injury associated with physical activity.

Table 7.1   Examples of Muscle- and Bone-Strengthening Activities by Age Group

Population

Type of activity

Muscle strengthening Bone strengthening

Children Games such as tug-of-war Modified push-ups (with knees on the floor) Resistance exercises using body weight or resistance bands Rope or tree climbing Sit-ups (curl-ups or crunches) Swinging on playground equipment or bars

Games such as hopscotch Hopping, skipping, jumping Jumping rope Running Sports such as gymnastics, basketball, volleyball, tennis

Adolescents Games such as tug-of-war Push-ups and pull-ups Resistance exercises with exercise bands, weight machines, handheld weights Climbing wall Sit-ups (curl-ups or crunches)

Hopping, skipping, jumping Jumping rope Running Sports such as gymnastics, basketball, volleyball, tennis

Adults and older adults

Exercises using exercise bands, weight machines, handheld weights Calisthenic exercises (body weight provides resistance to movement) Digging, lifting, and carrying as part of gardening Carrying groceries Some yoga exercises Some tai chi exercises

Reprinted from USDHHS, PAGA (2008).

In 2018, the Physical Activity Guidelines Advisory Committee concluded that there was strong scientific evidence that participation in community-based or home-based physical activity programs can significantly reduce the risk of injury from falls. These types of injuries can include bone fractures, head trauma, and soft-tissue injury. Older adults who are at risk for falls should include balance activities such as backward walking, sideways walking, heel walking, toe walking, and standing from a sitting position in their physical activity and exercise plans at least three times per week. Combining balance and muscle-strengthening activities for 90 minutes per week, along with moderate-intensity walking for 60 minutes per week, can maintain functional health and may reduce the incidence of falls. Emerging evidence indicates that higher-velocity resistance

movements at lower intensities may improve power in the elderly more than lifting at higher intensities and lower velocities.

The specific combinations of type, amount, and frequency of activities that might reduce falls are, unfortunately, unknown. However, some evidence shows that tai chi exercises may help prevent falls. Older adults can start balance and muscle- strengthening activities by holding on to stable supports (e.g., furniture) and wean themselves away from the supports over time.

FUNCTIONAL HEALTH Musculoskeletal health is not necessarily linked to a specific disease, but low levels of musculoskeletal health (low muscle mass and poor muscle function) can contribute to poor functional health, functional ability, and role ability. Functional health (sometimes called health- related quality of life) is a concept that suggests that an otherwise healthy person may live with some type of functional disability (USDHHS, PAGAC 2008, 2018) and includes two key subitems: functional ability and role ability. In a practical sense, functional health includes being able to physically do the things one wants to do without pain or limitation. The concept of functional health bridges the gulf between the performance-related orientation of physical activity and the health-related orientation of public health. It is the key reason physical activity is important.

At what age do many older people you know lose their functional health? Do you think regular physical activity helps maintain functional health longer? Why or why not?

Functional ability refers to the capacity to perform a task, activity, or behavior independently. For example, an elderly woman who is unable to go grocery shopping, lift and store her groceries at home (e.g., a heavy milk jug), or successfully move around a two- story house because of musculoskeletal limitations has a loss of functional ability. Role ability, on the other hand, refers to the ability to perform activities of daily living (ADLs) and instrumental activities of daily living (IADLs) (USDHHS, PAGAC 2008).

Examples include being able to play with her grandchildren or perform self-care tasks such as bathing and laundry. The loss of functional ability and role ability would obviously impair functional health, although factors other than physical changes (e.g., the mental health challenges of aging) could also negatively affect functional health.

The prevalence of poor functional health is difficult to determine in any population because it is multifactorial and a variety of definitions exist. However, it has been reported that the economic cost of fall injuries of those over 65 in the United States, which are often due to poor functional health, exceeded $19 billion in 2000. As the elderly population continues to grow, it is expected that the costs will reach $54.9 billion by the year 2020.

Figure 7.7 illustrates a model that links the relationships among lifestyle behaviors, health status, exercise science principles, and outcomes such as functional health and peak performance. Basic functional health should be a primary goal for everyone; beyond that, further participation in physical activity and exercise may lead to higher levels of performance. An understanding of basic exercise science principles is necessary for understanding how to maintain functional fitness, how to exercise, and how to face the challenges of maintaining physical activity and exercise (at least for health benefits), such as mobility challenges, medical management issues, and exercise rehabilitation challenges. For example, managing disease processes (e.g., type 2 diabetes) or maximizing the benefits of rehabilitation (after athletic injury or relapse) requires that people first maintain or regain their basic functional health; only then can they optimize performance. A primary message to share regarding developing and maintaining functional health and optimizing performance is that research has clearly demonstrated the importance of avoiding inactivity for maintaining and improving functional health (USDHHS, PAGAC 2008).

RISK FACTORS FOR POOR FUNCTIONAL HEALTH

Many of the risk factors for poor functional health overlap with those for osteoporosis, osteoarthritis, and low muscle mass as discussed earlier. This is because poor functional health is often a key by- product of these (and other) chronic conditions. Functional health is not necessarily linked to a specific disease process; however, being physically inactive for long periods of time reduces functional health. The basic risk factor for poor functional health is physical inactivity; existing or developing mobility challenges, medical management issues, and rehabilitation challenges further add to the risk.

Figure 7.7   Relationships among lifestyle behaviors, health status, exercise science principles, and outcomes such as functional health and peak performance.

Low levels of functional health, which can lead to falls and other disabling conditions, correlate highly with low levels of muscle mass quantity and quality. According to PAGAC (USDHHS, PAGAC 2008), the three primary risk factors associated with low levels of functional health are low aerobic capacity, a lack of muscular strength, and poor balance. In addition, cultural and social factors can affect functional health, including lack of social support (the absence of a human support network or assistance).

ASSESSMENTS OF FUNCTIONAL HEALTH STATUS SF-36 (long) and SF-12 (short) Measures multiple subdomains of functional health status including physical and role function. Originated in the Medical Outcomes Study (SF-36.org 2011).

Functional Independence Measure (FIM) Measures physical and cognitive disability (Center for Outcome Measurement in Brain Injury 2011a).

Functional Assessment Measure (FAM) Meant to supplement FIM by integrating additional concepts such as community integration, orientation, and emotional status (Center for Outcome Measurement in Brain Injury 2011b).

Quality of Well-Being Scale (QWB) One of the earliest functional health status tools; measures comprehensive quality of life and focuses to a large extent on disease symptoms (University of California at San Diego Health Services Research Center 2011).

COMMON TESTS OF FUNCTIONAL HEALTH The tests highlighted earlier in the chapter for osteoporosis, osteoarthritis, and muscle mass focus largely on physiological parameters. Functional health status is a complex concept that encompasses quality of life issues such as role functioning, physical functioning, social functioning, and emotional status. Because these

issues go beyond physiological concepts (although they are very much related to them), they are best measured using tests that focus on self-assessment or the assessment of a third party (e.g., a physician or researcher). These tests do not isolate one aspect of functional health (e.g., a muscle or joint), but rather, attempt to integrate observations into broad indexes of function. The highlight box Assessments of Functional Health Status lists some of the more common measures used to assess functional health status.

FITNESS RECOMMENDATIONS FOR FUNCTIONAL HEALTH Figure 7.8 shows the results from several research studies concerning the relationship between the amount of physical activity or exercise performed regularly and mobility limitations. The individuals who were in the lowest physical activity or exercise category were also those who needed medical evaluation due to their mobility limitations. Figure 7.9 also shows that more active people were at lower odds ratios, or less risk, for functional health problems as measured by various functional health, ADL, or IADL outcomes.

Figures 7.8 and 7.9 show clearly that higher levels of participation in physical activity and exercise are significantly associated with measures of better functional health. The diversity of methods used in the many research studies summarized does not allow us to speculate on a specific dose-response relationship between the amount of physical activity or exercise and functional health. However, the findings in figures 7.8 and 7.9 do illustrate that modest levels of physical activity and exercise are associated with lower risk for functional and role limitations.

SCIENTIFIC EVIDENCE There is moderate scientific evidence that physical activity and exercise, at midlife and beyond, reduce the risk of moderate to severe functional limitations (USDHHS, PAGAC 2008). There is also evidence that regular physical activity or exercise is safe and

improves functional ability. There is not currently enough evidence to show that physical activity or exercise improves or maintains role ability or prevents disability in older adults who already have functional limitations. Strong evidence suggests that regular physical activity or exercise is safe and reduces the risk of falls in older adults by 30%.

Figure 7.8   The relationship between increased physical activity levels and the risk of mobility limitations. Adapted from USDHHS, PAGAC (2008, G-6).

Figure 7.9   The relationship between increased physical activity levels and the risk of functional health problems as shown from several studies. Adapted from USDHHS, PAGAC (2008, G-6).

Participation in regular physical activity and exercise can prevent or delay function or role limitations (or both) by 30% (moderate to strong evidence). Risk reduction appears to be similar for men and women; evidence regarding relationships between physical activity and exercise and functional health for racial and ethnic groups is limited.

Moderate evidence suggests a dose-response relationship between physical activity and exercise and the prevention or delay of function and role limitations. The dose-response relationship between physical activity and exercise and the prevention of falls in older adults has not been tested. The dose of physical activity or exercise needed for prevention of falls is not known, but participation in walking activities can improve functional health. The maintenance or improvement of functional health requires at least 30 minutes of moderate- or vigorous-intensity physical activity three to five days per week, emphasizing aerobic and muscle-strengthening activities (strong to moderate evidence).

To lower the risk of falls, exercise programs should include balance training and muscle-strengthening activities three times per week for 30 minutes each session (strong evidence); adding moderate-intensity walking activities two or more other times per week is also recommended. Some evidence suggests that participation in tai chi one to three or more times per week may prevent falls.

The evidence for the effects of the accumulation bouts of physical activity and exercise throughout the day on functional health is not currently available. It is important to remember that most midlife and older adults have very low fitness levels. For this reason, any program of physical activity or exercise focused on improving or maintaining functional health should include slow progressions in the volume of activities to reduce the risk of adverse events.

GUIDELINES People who have lost some ability to perform a task of everyday life, such as climbing stairs, have a functional limitation. In older adults with existing functional limitations, scientific evidence indicates that regular physical activity is safe and improves functional ability. The Physical Activity Guidelines for Americans offer the following guidelines for achieving or maintaining functional health in adults with disabilities (USDHHS 2008):

Aerobic activity is recommended to be done throughout the week in sessions lasting at least 10 minutes, at one of the following levels and durations:

Moderate-intensity aerobic exercise totaling 150 minutes per week Vigorous-intensity aerobic exercise totaling 75 minutes per week A combination of the preceding

Muscle-strengthening activity for all major muscle groups is recommended at moderate or high intensity on two or more

days per week.

Adults with a disability who are not able to meet these recommendations should be encouraged to avoid inactivity by performing as much physical activity as they are able. They should discuss with their health care provider the type and duration of physical activity that is appropriate for their ability.

Adults with chronic conditions should engage in regular physical activity because doing so can improve their quality of life and reduce the risk of developing new conditions. The type and amount of physical activity should be determined by their abilities and the severity of the chronic condition. The Physical Activity Guidelines for Americans emphasize the following three messages for people with chronic medical conditions (USDHHS 2008):

Regular physical activity can confer important health benefits. Physical activity is safe if done according to abilities. People with chronic conditions should always consult with their health providers about which types of physical activity are appropriate.

For many chronic conditions, physical activity provides therapeutic benefits and is part of the recommended treatment for the condition. The Physical Activity Guidelines for Americans do not specifically address therapeutic exercise or rehabilitation.

LEADER PROFILE Sandra M. Mahecha, MD, PhD

Why and how did you get into the field of Physical Activity and Public Health? When I finished my medical training in Colombia, I was interested in what we knew then as the field of sports medicine. At the time there was no formal sports medicine specialty in Columbia, so I went to Brazil for the coursework and to simultaneously perform an internship in a research center—Centro de Estudos do Laboratório de Aptidão Física de São Caetano do Sul (CELAFISCS), where I would research physical activity, exercise, and performance. In 1994, the secretary of health in the state of São Paulo requested a community physical activity program as a form of health promotion, so this is how my interest and study began in the area. For 24 years I was directly involved with the Agita São Paulo Program and the physical activity networks, Red de Actividad Física de las Américas (RAFA) and Agita Mundo. After leaving Brazil, I followed my dream to promote physical activity in Chile, where I currently run a physical activity promotion program in the most famous sports medicine clinic in the country, Clínica MEDS, and launched the new specialty of sports medicine and physical activity with the Universidad Mayor and Clínica MEDS. This has been a way to continue developing projects to improve the health of the population through the regular practice of physical activity.

Did any one person have a major influence on your career? How? Without a doubt my academic, professional, and personal training was accomplished thanks to the support of CELAFISCS members and the leadership of Victor Matsudo,

who knew how to lead and encourage us for this purpose in Brazil and Latin America. With his vision I was able to learn to research with limited resources and to transform theory into practice. In the same way, Dr. Fernando González Foretic in Chile was a key person who created opportunities, contacts, alliances, and systems of delivering physical activity to different sectors of society.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My primary interests are to promote physical activity in vulnerable populations such as adults, frail people, and institutionalized older adults; I continue to be committed to implementing the SENIOR FIT program that we developed as an exercise program for active and healthy aging. In addition, I hope to see professionals trained in health and exercise, not only with doctors in the specialty, but also in clinical physiology of exercise and prescription of exercise programs for older adults. In addition to this I have a strong commitment to the theory “exercise is medicine,” and to make physical activity a part of the training and focus for all doctors and health professionals in Chile and Latin America.

Why do you do what you do? Because it’s my dream, and it’s what I love doing. I consider it a small contribution to make people live better and happier!

What are two key issues that must be addressed by 2030? The recommendation that physical activity be included as a formal part of health care (private and public) everywhere in the world, and that physical activity be encouraged in people with rare or little-known chronic diseases.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

The prevalence of common musculoskeletal challenges such as osteoporosis (bone health), osteoarthritis (joint health), and low levels of the quantity and quality of muscle mass are high in the U.S. population. Osteoporosis (i.e., low bone mass and structural deterioration of bone tissue) is estimated to be a public health threat to 44 million Americans, or 55% of those over 50 years of age. Osteoarthritis (OA) is the most common form of joint disease and is associated with joint pain and dysfunction along with an irreversible loss of articular cartilage. Functional health is a concept that suggests that an otherwise healthy person may have some form of functional disability and includes the maintenance of functional ability and role ability. Functional ability refers to the capacity to perform a task, activity, or behavior independently. Role ability refers to the ability to perform activities of daily living (ADLs) and instrumental activities of daily living (IADLs). Common risk factors for most musculoskeletal disorders are physical inactivity, overweight, sex, heredity, and age. The physiological, biomechanical, and psychological benefits of participating in physical activity and exercise on musculoskeletal health are numerous. Common musculoskeletal tests can be used to determine levels of strength, muscular endurance, power, balance, gait, and mobility. Youth should engage in muscle-strengthening activities that include the major muscle groups at least three days per week, and adults should participate at least two days per week. Common risk factors for low levels of functional health are physical inactivity, low physical fitness, tobacco use, age, sex, and heredity or genetics.

Simple tests of functional health address muscular strength, muscular endurance, balance, gait, and mobility. Moderate levels of physical activity or exercise are associated with lower risk for functional and role limitations. Participation in regular physical activity and exercise can prevent or delay function and role limitations and reduce the risk of falls in older adults by 30%.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Baechle TR, Earle RW, eds. National Strength and Conditioning

Association. 2008. Essentials of Strength Training and Conditioning, 3rd ed. Champaign, IL: Human Kinetics.

Center for Outcome Measurement in Brain Injury. 2011a. Introduction to the FIM. www.tbims.org/combi/FIM. Accessed 11 January 2019.

Center for Outcome Measurement in Brain Injury. 2011b. Introduction to the Functional Assessment Measure. www.tbims.org/combi/FAM. Accessed 11 January 2019.

Fiatarone MA, O’Neill EF, Ryan ND, et al. 1994. Exercise training and nutritional supplementation for physical frailty in very elderly people. New England Journal of Medicine 330: 1769- 1775.

Gettman LR, Pollock ML. 1981. Circuit training: A critical review of its physiological benefits. Physician and Sportsmedicine 9: 44-

60. Kotlarz H, Gunnarsson CL, Fang H, Rizzo JA. 2009. Insurer and

out-of-pocket costs of osteoarthritis in the U.S. Arthritis and Rheumatism 60 (12): 3546-3553.

National Arthritis Foundation. 2011. www.arthritis.org. Accessed 11 January 2019.

National Osteoporosis Foundation. 2010. www.nof.org. Accessed 11 January 2019.

SF-36.org. 2011. www.sf-36.org. Accessed 11 January 2019. Tosteson AN, Melton LJ, Dawson-Hughes B, Balm S, Favus MJ,

Khosla S, Lindsey RL. 2008. Cost-effective osteoporosis treatment thresholds: The United States perspective. Osteoporosis International 19: 437-447.

University of California at San Diego Health Services Research Center. 2011. Quality of Well-Being Scale–Self Administered (QWB-SA). https://hoap.ucsd.edu/qwb-info. Accessed 11 January 2019.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

2.2.3, 2.3.2, 2.5.1, 6.2.1, 6.2.2, 6.2.3, 6.2.4, 6.4, 6.4.1, 6.4.2, 6.4.3, 6.4.4, 6.5.2

CHAPTER 8 Cancers

OBJECTIVES

After completing this chapter, you should be able to discuss the following:

»  The definition of cancer and which types are affected by physical activity

»  The prevalence of cancers affected by physical activity »  Possible mechanisms by which physical activity can lower

cancer risk »  Physical activity guidelines for cancer prevention »  How physical activity can be a part of cancer survivorship

OPENING QUESTIONS »  What is cancer, and how can physical activity play a role in

its prevention?

»  What evidence exists that shows that physical activity can reduce cancer risk?

»  How much physical activity is sufficient to reduce cancer risk?

»  How can physical activity help people who have survived a bout with cancer?

Just the mention of the word cancer evokes many images and emotions for many people. Most people have known a relative, friend, or acquaintance who has had, is currently diagnosed with, or has died from some type of cancer. Although referring to cancer as a disease in the singular is convenient, many types exist, and they are unique. Cancer is actually a group of diseases, each with its own risks, etiologies, and pathologies. Cancers are defined as diseases with processes associated with uncontrolled abnormal cell growth and proliferation. Many cancers can recur after successful treatment or can spread to organs and systems other than their origin (also known as metastases). Many types of cancer are rapidly fatal,

whereas others offer a very positive prognosis, particularly when diagnosed early.

Although much of the work in the area of physical activity and health has focused on the cardiovascular system and traditional physiological responses to exercise training (see chapters 2 and 5), in the past three decades, substantial evidence has emerged demonstrating that physical activity plays an important role in preventing certain cancers. Early physical activity and cancer studies established strong evidence determining that regular physical activity helps to prevent colon cancer and breast cancer. However, during the past decade, strong evidence has now emerged linking physical activity to the prevention of more cancers. The 2018 Physical Activity Guidelines Advisory Committee Report concluded that in addition to colon and breast cancer, regular moderate- to vigorous-intensity physical activity reduces the risk of developing bladder, endometrium, esophagus, kidney, and stomach cancers. The proposed physiological mechanisms of action by which physical activity contributes to cancer prevention are intriguing because they involve systems in the body that exercise physiology research has not focused on. In addition to questions of primary prevention, a growing body of evidence supports a role for physical activity in improving cancer prognoses and the for the quality of life of people who have cancer (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2018).

PREVALENCE OF CANCERS Different cancers have varied causes in people. Many cancers are idiopathic—meaning that the cause in a given person may never be known. The concepts of risk factors and probability have helped our understanding of cancers. For example, although cigarette smoking is one of the most insidious risk factors for lung cancer and the probability of cancer is much higher among cigarette smokers as compared to non-smokers, some people who have never smoked a

cigarette are diagnosed with lung cancer. Cancers are caused by both internal factors (e.g., heredity, immune dysfunction, and abnormal metabolism) and external factors (e.g., behaviors such as smoking and a sedentary lifestyle, pollution, and radiation exposure). These factors can act alone or in synergy over time to produce uncontrolled cell growth and proliferation.

Evidence is very clear that the interaction between the environment and genetics is a possible trigger for cancerous cell changes. For example, a person may have a family history (heredity) of a certain type of cancer, thus possibly carrying a genetic code that may increase cancer risk. That genetic disposition toward cancer may never be expressed if it does not come into contact with an environmental exposure (e.g., cigarette smoke); such contact, though, may trigger the expression of the gene, causing the cells to become cancerous.

Cancers were the second leading cause of death in the United States in 2017, affecting 40% of men and 38% of women during their lifetimes. Only about 10 to 15% of cancers are linked to heredity; the remaining cases are thought to be related to external factors such as lifestyle or environmental factors. In the United States 1,620 people per day were estimated to die from cancers in 2015. Cancer accounts for 23% of all deaths in the United States (Centers for Disease Control and Prevention 2016). Globally, cancer killed an estimated 9.6 million people in 2018 (World Health Organization 2018), and the rate is expected to increase to 23.6 million as a result of the growth and aging of the world’s population (National Cancer Institute 2018b).

Notably, research has demonstrated that many cancers may be due to health behaviors and, thus, are theoretically preventable. The American Cancer Society (2017) estimated that 45% of the total 587,521 U.S. deaths from cancers in 2014 were related to lifestyle factors such as overweight and obesity, physical inactivity, unhealthy eating, and smoking. Lee and colleagues (2012) estimated that 10%

of breast and colon cancer cases globally were due to physical inactivity (i.e., not meeting physical activity guidelines).

The economic burden of cancer is, not surprisingly, a complicated topic. Different cancers have different health effects—some are rapidly fatal, others are treatable but carry a long burden of illness, and still others are curable if diagnosed early. Thus, direct costs (i.e., how much money is needed for treating the disease in the hospital, and how much money is needed to pay for physicians, nursing home services, and pharmaceuticals) as well as indirect costs (e.g., changes in health-related quality of life, lost productivity due to disability and death) differ by cancer type. Age is also an important issue. Cancers that occur later in life, on a population level, cost less than those in younger people. Cancers occurring in countries with medical care delivery systems that are different from that of the United States have different economic costs than similar cancers in the United States.

Many risk factors for cancers are modifiable. What are the barriers to reducing these risks?

The American Cancer Society (2015) estimated that the economic costs due to direct medical care of all cancers in 2015 was $80.2

billion (USD). This estimate does not include the costs resulting from lost productivity among people living with cancer, or costs due to lost productivity among people who died from cancer. Clearly, the economic burden, in addition to health and social burdens, is important to address as a public health problem.

Because cancers are such a significant health burden, and because disease surveillance is so central to public health, many useful sources of cancer statistics are available. These statistics are important in many ways, but one key way is to help us distinguish new cases of cancer (incidence) from existing cases (prevalence). Because more people are living longer with cancers than at any other time in history, which is due to impressive advances in therapy, the number of existing cases of cancers is on the rise (prevalence). If we could not distinguish these existing cases from the new cases (incidence) we would incorrectly assume that cancer is an increasing problem simply because more people are living longer with cancer.

One excellent resource for cancer information in the United States is the National Cancer Institute, one of the institutes at the National Institutes of Health (NIH). The Cancer Surveillance Epidemiology and End Results (SEER) program has been operating since the early 1970s and is the definitive web resource for cancer mortality, incidence, and prevalence data by sites affected and overall (http://seer.cancer.gov).

CANCER RISK FACTORS Before considering the risk factors for cancers, we should have an understanding of how cancer starts and progresses in general. Despite multiple types of cancers with various etiologies, the process by which normal cells change and become cancerous is thought to be common to all cancers. In this multistage model of carcinogenesis, outlined in figure 8.1, a subset of normal cells becomes initiated for a cascade toward uncontrolled proliferation in stage 1. This initiation can be the result of a genetic mutation, a spontaneous change, or an external cause. The genetic material is

altered, which makes the affected cells more likely to grow more rapidly than unaffected cells.

In the second stage of the multistage process of carcinogenesis, promotion, some of these initiated (converted) cells become precancerous through additional genetic changes as a result of the altered state they entered in the initiation stage. The promotion stage is characterized by the rapid proliferation of these altered cells.

Figure 8.1   Multistage model of carcinogenesis. Adapted from Rogers et al. (2008).

Some of the cells that have proliferated during the promotion stage will progress to the third stage of progression. In this stage, proliferating precancerous cells become full, invasive tumors, and cancer is subsequently diagnosed.

Why is this model important? The multistage model of carcinogenesis, which includes initiation, promotion, and progression, allows us to hypothesize about and study the possible mechanisms by which physical activity and other factors may interrupt this process and prevent cancers. Although they are still working largely with animal models, researchers are aggressively studying how physical activity may affect (and prevent) key genetic changes and their cellular expressions at each of these three stages (Rogers et al. 2008).

A list of general risk factors associated with developing cancers follows. Specific cancers may have additional risk factors that can cause cellular damage internally (e.g., mutations and immune conditions), such as hormonal regulation or nutrient metabolism, or externally, such as tobacco use, chemicals, and sun exposure. As discussed earlier, even though heredity is listed here as a nonmodifiable risk factor, how inherited genes are expressed depends on interactions with environmental exposures. Modifiable Risk Factors for Cancer

Physical inactivity Obesity Tobacco use Poor nutrient intake Excessive sun exposure Toxic environmental exposure

Nonmodifiable Risk Factors for Cancer

Age Heredity (genetics) Sex

Following are descriptions of the modifiable and nonmodifiable risk factors for cancer:

• Physical inactivity. Physical inactivity is emerging as an important risk factor for several prevalent cancers; meeting physical activity guidelines may lower the risk of developing these cancers.

• Obesity. As with CVD risk, having a BMI greater than or equal to 25 kg/m2 (overweight) or 30 kg/m2 (obesity) significantly increases the risk of most cancers.

• Tobacco use. Chronic smoking is associated with lower levels of aerobic capacity and functional health. Tobacco use was associated

with 169,000 cancer deaths in 2009 and is the main risk factor associated with cancers of the lung and bronchus.

• Poor nutrient intake. The consumption of a diet that is low in essential nutrients (e.g., those found in fresh fruits and vegetables), practicing risky behaviors (e.g., excessive alcohol intake), or both, can increase the risk of cancers.

• Sun exposure. Excessive exposure to the sun’s rays and indoor tanning (i.e., nonionizing radiation) are the primary risk factors associated with skin cancers.

• Toxic environmental exposure. Long-term exposure to environmental toxins such as chemicals, ionizing radiation, and infectious diseases can increase the risk of most cancers.

• Age. The risk of developing cancer increases the longer one lives because most cancers develop over time from damaged genes. The majority of cancers (>70%) occur in adults who are over 55 years of age.

• Heredity (genetics). Although cancer risk depends somewhat on genetics, engaging in positive behaviors such as being physically active, eating healthily, maintaining a healthy weight, and minimizing risky activities can lessen overall risk by improving functions such as circulation, ventilation, bowel transit time, energy balance and immune function, and DNA repair (Thune and Furberg 2001).

• Sex. Some cancers are sex specific. Prostate cancer in men and reproductive system cancers in women (ovarian, endometrial) are examples of sex-specific cancers.

KINESIOLOGY AND CANCERS As noted in the 2018 PAGAC, a relationship between physical activity and reduced cancer risk has been found consistently for breast and colon cancers over the past two decades (see table 8.1). More recently, it has been determined that there is also strong evidence linking physical activity to the prevention of cancers of the bladder, endometrium, esophagus, kidney, and stomach.

Additionally, there is some evidence suggesting an association between regular physical activity (as compared to inactivity) and a lowered risk for lung cancer; however, this evidence is not yet conclusive. Emerging research is currently studying potential links between physical activity and blood, head and neck, pancreas, prostate, and ovary cancers, but to date, little evidence supports relationships between physical activity and risks for other cancers, beyond those cancers mentioned in this chapter.

Table 8.1   Estimated New Cases and Deaths per Year (2018) from Cancers for Which Physical Activity is a Protective Factor

Type of cancer

Estimated new cases number (% of all new cancer cases)

Estimated deaths number (% of all cancer deaths)

Bladder 81, 190 (4.7%) 17,240 (2.8%)

Breast (female) 266,120 (15.3%) 40,920 (6.7%)

Colon and rectum 140,250 (8.1%) 50,630 (8.3%)

Endometrium (uterine) 63,230 (3.6%) 11,350 (1.9%)

Esophagus 17,290 (1.0%) 15,850 (2.6%)

Kidney & renal pelvis 65,340 (3.8%) 14,970 (2.5%)

Stomach (gastric) 26,240 (1.5%) 10,800 (1.8%)

Total for cancers for which PA is a risk factor

659,660 (38.0%) 161,760 (26.5%)

Total for all cancers 1,735,350 (100%) 609,640 (100%)

Data from the National Cancer Institute (2018).

The positive effects of physical activity for cancer survivors are becoming clearer each year with new research.

The earliest and strongest evidence of a link between physical activity and cancer showed an inverse relationship between cancer of the colon and physical activity. Today, there is extensive and strong evidence demonstrating that high amounts of recreational, occupational, and total physical activity help prevent the development of colon cancer. Moreover, Harris and colleagues (2009) and the World Cancer Research Fund International and American Institute for Cancer Research (2011) have found strong evidence indicating that association between colon cancer and

physical activity is best described as a dose-response. This means that the higher the level (dose) of regular physical activity, the lower the risk of developing colon cancer. Finally, there is sufficient and strong evidence demonstrating that both men and women benefit from the positive effects of physical activity on colon cancer risk reduction. Many studies using various designs and types of participants have been conducted over the years. The most recently published meta-analysis (a study compiling findings from the best studies of a given topic) on colon cancer and physical activity was conducted by Liu and colleagues (2016). They concluded that, after controlling for the differences in study design and other factors, the people who were most physically active had a 19% lower risk of developing colon cancer than those who were least active.

The fact that higher levels of physical activity are associated with lower risks of breast cancer is an exciting one, particularly given the prevalence of breast cancer among women. About one in eight women living today will be diagnosed with breast cancer during her lifetime. With recent time trends for the disease being relatively stable, breast cancer is clearly an important health problem to address.

Like with colon cancer, an extensive body of various scientific studies have been conducted over the years, demonstrating a clear link between physical activity and breast cancer risk. A recent meta- analysis by Wu and colleagues (2017) found the average risk of breast cancer to be 10 to 15% lower among the most physically active women compared to similarly inactive women. The amount of physical activity needed to reduce the risk of breast cancer has been estimated to be the equivalent of brisk walking 45 to 60 minutes or more per day, five or six days per week (McTiernan 2008). Recent studies have examined the protective effect of physical activity on breast cancer risk reduction by looking separately at pre- versus post-menopausal women. Wu and colleagues found that the most physically active pre-menopausal women have a 14 to 31% lower risk of developing breast cancer than inactive pre-menopausal

women. Likewise, the most physically active post-menopausal women have an 8 to 13% lower risk of developing breast cancer than their inactive counter parts. These findings are interesting, because they reveal that the risk reduction for breast cancer due to physical activity may be greater among pre-menopausal women. However, other researchers have conducted similar studies, finding no substantial differences in risk of breast cancer by menopausal status. The one clear message is that engaging regularly in physical activity helps all women, regardless of life-stage, in preventing breast cancer. Moreover, strong evidence from several studies is also now available demonstrating a dose-response relationship between levels of physical activity and breast cancer risk reduction: The more physically active a woman is, the lower her risk of developing breast cancer. The field of study of cancer and physical activity epidemiology has evolved rapidly over the past 10 years. It is now well established that physical activity is a critical protective factor for a variety of cancers. Strong evidence from several meta-analyses is now available quantifying the protective effects of physical activity on other cancers beyond those of the colon and breast sites. Keimling and colleagues (2014) report a 20% lower risk of bladder cancer among highest versus lowest activity groups. Keum and colleagues (2014) found that women with the highest levels of physical activity had an 18% lower risk of endometrial (uterine) cancer than those in the most inactive category. Behrens and colleagues (2014) conducted a comprehensive meta-analysis of the effect of physical activity on esophageal cancer and found that highly active people have a 21% lower risk of developing esophageal adenocarcinoma. In 2013, Behrens and colleagues also examined the evidence on the effect of physical activity on renal cancer (of the kidney). They estimated a 12% lower risk of kidney cancer among individuals with the highest levels of physical activity, as compared to those with the lowest levels. Finally, in 2014, Singh and colleagues reported a 19% lower risk of gastric (stomach) cancer among very active people in contrast to those with very low levels of physical activity. Other

studies are underway examining the potential role of physical activity on preventing even more cancers.

Friedenreich and Cust (2008) showed that all types of physical activity were associated with a lower risk of breast cancer—a remarkably consistent finding. Women who were more physically active in their jobs or who had a measurable amount of physical activity while traveling had a lower risk of breast cancer. Women participating in recreational physical activity seemed to have an even lower risk. Why might this be?

Although strong scientific evidence supports a dose-response relationship between physical activity and lower risk of several cancers, the specific physiological mechanisms by which this lower risk might be operating remain under study. In the last 15 years, researchers have started to study the biological mechanisms of, and links between, the specific dose-response relationships between physical activity and cancer risks. Some of the chronic exercise- related adaptations that have been reported to lower the risks for cancers are shown in the highlight box Potential Mechanisms Through Which Physical Activity Lowers Cancer Risk.

PHYSICAL ACTIVITY EXPOSURE IN CANCER STUDIES Cancer is an extremely difficult disease to study in free- living populations. This is especially true in studies of physical activity exposure and cancer risk. The multistage model of carcinogenesis can occur fairly rapidly (e.g., over the course of a few years) or over a lifetime. This

means that knowing when the exposure to a risk factor such as physical inactivity occurred is very important. For example, several researchers have hypothesized that physical activity may be more important for cancer prevention in certain periods of life than in others (e.g., it may be more important during early adulthood than during later adulthood, which is closer to when the disease develops). Others take the contrary view that a constant and sustained exposure to physical activity is

most important—that lifetime exposure to physical activity confers the lower risk. Either way, long-term studies that follow people over their lifetimes are critical for answering these questions. What do you think? Would you be willing to be followed throughout your life to participate in such a study?

Most of the contributions of kinesiology to our understanding of cancer mechanisms come from exercise physiology. Research laboratories around the world have focused attention on how exposure to physical activity may block key steps in the multistage carcinogenesis process. Biomechanical and behavioral factors, although important, have not been identified as central to the mechanisms of physical activity that affect the development of cancer.

POTENTIAL MECHANISMS THROUGH WHICH PHYSICAL ACTIVITY LOWERS CANCER RISK

Avoidance of weight gain or weight loss

Reduced insulin resistance

Lower systemic low-grade inflammation

Lower colon transit time

Lower production of sex hormones

Improved immune function

The scientific literature seems to support at least six likely explanations—through two different pathways—of how physical activity reduces the risk of cancers. One pathway is an indirect one: Physical activity affects body composition and adiposity. These changes in body composition lower cancer risk indirectly by changing factors associated with higher body fatness, such as positively affecting biomarkers of systemic inflammation (a marker

for several types of chronic disease including cancers), improving insulin resistance (i.e., improving the ability of the hormone insulin to clear glucose from the body), increasing blood insulin levels, and lowering the production of sex hormones (estrogens and androgens).

Physical activity can also reduce the risk of cancer directly (i.e., not through reducing adiposity). The direct physiological effects of physical activity on skeletal muscle improve insulin resistance. Physical activity has also been shown (independent of adiposity) to improve levels of sex steroid hormones (androgens and estrogens), improve biomarkers of low-grade inflammation, and improve immune function. Further, physical activity can work mechanically to reduce colon transit time, thus reducing the time potential carcinogenic compounds are in contact with the digestive system. This is one of the key hypothesized mechanisms for physical activity preventing colon cancer.

It is fairly clear that sex hormones are important in cancer risk. Higher levels of circulating estrogens and androgens place women at higher risk of breast cancer. This appears to be especially true for postmenopausal women. Exercise training has been shown to decrease circulating sex hormones directly and through fat loss. The positive effects of physical activity on sex hormones can be expected as a result of moderate-intensity as well as vigorous-intensity physical activity.

Higher insulin resistance has been associated with several types of cancer, and insulin has been shown to increase cell proliferation coincident with the multistage model of carcinogenesis (see figure 8.1). Physical activity and exercise very clearly lower insulin resistance (allowing for glucose to be cleared from the body more efficiently) via improved cellular metabolism both acutely (i.e., immediately after a single exercise bout) and chronically (i.e., among those who are habitually physically active). Interestingly, this effect has been shown for aerobic physical activity as well as resistance training.

The interrelationship among immunity, cancer, and physical activity is a complicated topic that researchers are only just now starting to investigate. Because of the uncontrolled differentiation and multiplication of cells that characterize most cancers, the body’s immune system has long been a target for understanding cancer prevention and treatment. This is because we normally depend on the immune system to isolate and eliminate foreign or abnormal cells.

Small, short-term exercise training studies have been shown to increase individual markers of immune function, and this response has been maintained for several hours after the cessation of exercise. Further, a positive dose-response association between physical activity intensity and immune function has been shown; more improvement has been observed with higher-intensity activity. The longer-term association with chronic exercise is unclear. However, bouts of vigorous-intensity exercise (such as those performed by elite athletes who may overtrain) over time may actually lower immune function and increase the risk of acute infections such as those of the upper respiratory tract. Clearly, much research is needed on this promising topic.

SCREENING FOR EARLY DIAGNOSIS OF CANCER Screening is an extremely effective way to catch several types of cancers early. A variety of regular screening tests are used to detect precancerous growths and stage 1 cancers. (Cancer occurs in four stages: stage 1 is early- stage cancer, and stage 4 is late-stage, or advanced). As noted in “Cancer Facts and Figures” (American Cancer Society 2018), cancers of the cervix, colon, and rectum can be prevented by removing precancerous tissue. Cancers of the breast, colon, rectum, cervix, prostate, oral cavity, and skin can also be diagnosed through screening. Self-screenings for many cancers (e.g., breast and skin) are valuable for personal awareness and may result in the early detection of disease.

PHYSICAL ACTIVITY AMONG CANCER SURVIVORS Is there a benefit to being physically active after being diagnosed with cancer, perhaps during and after treatment? With improved cancer treatments and earlier, more effective diagnostic techniques, more and more people are living with cancer. In 2016, an estimated 15 to 16 million people in the United States were living with cancer or had survived a bout of cancer. This number is expected to become larger, and increase to about 20 million cancer survivors by 2026 (National Cancer Institute, 2018b).

A cancer diagnosis is a difficult situation filled with many psychological and physiological changes—as a result of both the disease and the therapeutic regimens used to control the disease. Chemotherapy, radiation, and surgery are standard cancer treatments, and all can negatively affect the body in the quest to reduce or eliminate a cancerous tumor. Hormone therapy and steroid treatments that accompany some cancer treatments can also have deleterious effects. Issues such as fatigue, lymphedema (i.e., localized fluid retention secondary to radiation therapy), cardiorespiratory fitness, muscular strength and endurance, quality of life, self-esteem, and safety (i.e., risk of adverse events) are most important to cancer survivors.

In 2010, Speck and colleagues published a comprehensive review of studies of cancer survivors (n = 6,838). These researchers reviewed 82 studies that examined some effect of exercise training or physical activity during and after cancer treatments. Overwhelmingly, breast cancer has been the cancer most frequently examined for benefits of physical activity. Because cancers are unique diseases, however, the effects of physical activity on breast cancer survivors may not be attributable to survivors of colon cancer, endometrial cancer, prostate cancer, or other types of cancer.

A listing of the health benefits of physical activity for cancer survivors is shown in table 8.2. Factors are categorized according to when their effects were studied: during or after cancer treatment. Although dozens of health and physiological outcomes have been

investigated, the factors listed in the table are those that have been consistently shown to result from increased exercise or physical activity across several studies.

Table 8.2 suggests that physical activity has some consistent positive effects on several physical and psychological parameters among cancer survivors. Clear and substantial gains in upper and lower body strength can be expected among cancer survivors after treatment, and small to moderate gains can be expected even during treatment. Although observed effects are not large for other physiologic outcomes, this emerging evidence gives substantial credibility to the belief that physical activity programming should be part of cancer survivors’ therapy.

PHYSICAL ACTIVITY GUIDELINES FOR CANCER PREVENTION At least 300 years ago, scientists first suggested that physical activity plays a role in cancer prevention; however, specific mechanisms of how this may happen and recommendations about the levels required for prevention have been articulated only in the past 15 years or so.

Table 8.2   Summary of Physical Activity Effects Among Cancer Survivors

Parameter Improvement after cancer treatment

Improvement during cancer treatment

Upper body strength Large Small to moderate

Lower body strength Large Small to moderate

Breast cancer–specific concerns

Large —

Cardiorespiratory fitness

Small to moderate Small to moderate

Fatigue Moderate Small to moderate

Overall quality of life

Small to moderate Small to moderate

Anxiety — Small to moderate

Self-esteem — Small to moderate

Physical activity participation

Small to moderate Small to moderate

Symptoms and side effects*

Small to moderate —

*Symptoms and side effects include nausea, lymphedema, and pain. Data from Speck et al. (2010).

SCIENTIFIC EVIDENCE The Physical Activity Guidelines Advisory Committee (USDHHS, PAGAC 2018) noted strong scientific evidence of an inverse relationship between participation in physical activity and exercise and the risk of breast, colon, bladder, endometrial, esophageal, kidney, and stomach cancer. The strongest evidence, including evidence of a dose-response relationship, is for breast and colon cancer. Participation in regular physical activity and exercise can lower the risk of colon cancer by 19% and the risk for breast cancer by 12%. The association is strong regardless of sex or age and moderate when race and ethnicity are taken into consideration.

LEADER PROFILE Andrea Ramirez Varela, MD, MPH, PhD

Why and how did you get into the field of Physical Activity and Public Health? I entered the field of medicine in 2004 with the goal of not only becoming a dedicated physician who treats disease but one who also understands that health and disease occur in the complex interplay between individual, biological, environmental, and socioeconomic factors.

After being exposed to the different specialty areas of medicine, I sought out experiences that would help me choose the field that would allow me to best serve my country (Colombia) and make a difference by helping improve health conditions. Specifically, I worked as a teaching assistant for the undergraduate epidemiology course at Universidad de los Andes, in Bogotá, Colombia, and I volunteered at three health care brigades, which aimed to prevent illness through health education and provide medical consultation to treat common diseases.

In 2010, I graduated from the Universidad de los Andes School of Medicine. By this point, I was certain that I wanted to dedicate the rest of my medical career and life to disease prevention and health promotion.

Medical programs in Colombia require a year of social service after graduating, which can be done in a clinical setting or by doing research. I chose research in the area of chronic disease prevention. Cardiovascular disease is currently the leading cause of death in Colombia while cancer is now one of the top 10 causes of death. For a year I worked on various public health research projects, including coordinating the Colombian site for the International Physical Activity and the Environment Network (IPEN), a multicountry study directed by Dr. James

Sallis of the University of California, San Diego. The objective of the IPEN project was to determine the association between built-environment characteristics and physical activity in adults in 14 countries worldwide. I managed the ethical component of the project, supervised the fieldwork, made cultural adaptations to the study instruments (e.g., surveys such as the International Physical Activity Questionnaire [IPAQ] and the Neighborhood Environment Walkability Scale, accelerometers, and anthropometric measurement tools), conducted built-environment measurements, managed data quality control, conducted statistical analyses, and prepared manuscripts for publications. My goal in the project was to gain the skills necessary to work as a specialist and researcher in future preventive medicine projects. This experience showed me that prevention alone is a highly effective intervention to maintain human health.

In 2011, I became the project manager for the Colombian site of the International Study of Childhood Obesity, Lifestyle and Environment (ISCOLE), led by Peter Katzmarzyk from the Pennington Biomedical Research Center in Baton Rouge, Louisiana. The project aimed to determine the relationship between lifestyle characteristics, obesity, and weight gain in 10-year-old children across 12 countries. I was excited to be part of this project due to its focus on childhood obesity, which is a growing problem in Colombia, despite the lingering prevalence of childhood undernutrition. The project gave me important insight into the ethical aspects of research involving children, measures of the built environment around schools, and how to apply food frequency questionnaires. The experience also made my career choice of preventive medicine more pronounced.

In addition to my work in clinical and community settings, I was involved in coordinating short research courses as part of a capacity-building project led by Dr. Michael Pratt of the Centers for Disease Control and Prevention (CDC). I helped coordinate the course in Santiago, Chile, in January 2011, and co-taught a workshop on physical activity measurement using accelerometers. I was also part of the CDC think tank on Physical Activity and Behavior Change, which took place in December 2011 in

Bogotá, Colombia. Also, in September 2012, I participated as an organizer and speaker for a national course led by the CDC, Universidad de los Andes, and Coldeportes, a government entity in Colombia. The course content included policies and programs for chronic disease prevention through physical activity, and was an excellent example of cooperation between government, private, and academic institutions to train physical activity promoters throughout the country.

In 2013, I received a scholarship to attend the Physical Activity and Public Health Course for Practitioners directed by Dr. Russell Pate in Utah, then started a Master of Public Health program at Universidad de los Andes. In 2014, I began working as the coordinator of the Global Observatory for Physical Activity—GoPA!.

Early in 2015, I moved to Brazil and started a PhD program in epidemiology in the Postgraduate Program in Epidemiology at Universidade Federal de Pelotas (UFPeL), supervised by Dr. Pedro Hallal from UFPeL and Dr. Michael Pratt from University of California, San Diego. My doctoral research was based on the GoPA! project and from that moment physical activity surveillance became my main area of research.

During 2017, I was a research scholar in the Department of Family Medicine and Public Health at University of California, San Diego. During my PhD program I

participated as a research assistant in the 2016 Lancet series on physical activity, and as a speaker in global research and practice courses for physical activity and public health in Mexico, Brazil, and Colombia.

Did any one person have a major influence on your career? How? Working in the physical activity and public health field has allowed me to meet not only outstanding researchers but also wonderful friends. I would like to acknowledge Michael Pratt and Pedro Hallal, my PhD supervisors, who have taught and mentored me over many years. Their vision, support, and motivation helped incredibly on my path to becoming an epidemiologist and researcher. Mike and Pedrinho are visionaries who believe in the leadership of Latin American women in the physical activity and public health field.

It has been a great pleasure to work with them and I look forward to doing so for many more years. Isaac Newton’s quote describes the major influence Mike and Pedro have had on my career: “If I have seen further than others, it was only by standing upon the shoulders of giants.”

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My research interests are global physical activity epidemiology and surveillance; global public health capacity for chronic disease prevention and physical activity promotion; and translation research, especially in Latin America.

I translate research into practice in my daily work. The collaboration and work that is done with every country representative in GoPA! allows me to disseminate and put into practice new and acquired knowledge with the GoPA! community. Furthermore, I am in frequent contact with the GoPA! and the International Society for Physical Activity and Health (ISPAH) network at the local and regional levels.

Why do you do what you do? I am passionate about my work and research area. I feel very excited and enthusiastic about being in contact with and learning from people all around the world.

What are two key issues that must be addressed by 2030?

1. Capacity building (i.e., the process of developing knowledge and skills among individuals and

organizations to carry out self-sustained public

health research and practice in their own settings),

funding opportunities and research positions favoring

women as principal investigators, studies on

interventions, policy, translation, and scalability.

2. Stronger and more integrated and multidisciplinary collaboration between policy makers and researchers,

as is being done by global initiatives like GoPA! and

Global Action Plan for Physical Activity (GAPPA).

A substantial amount of evidence indicates a dose-response association between physical activity and exercise and a lower risk of developing colon or breast cancer, which is consistent with the recommendation of 30 to 60 minutes of moderate- to vigorous- intensity physical activity every day. Data for this effect are strongest in relation to aerobic leisure time (recreational) physical activity. A growing body of strong evidence suggests that breast cancer survival (i.e., quality of life and fitness) is associated with participation in regular physical activity and exercise.

GUIDELINES The levels of physical activity associated with cancer risk reduction can be attained by following the Physical Activity Guidelines for Americans as described for cardiorespiratory health (see chapter 5) and musculoskeletal health (see chapter 7). Adults should engage in 150 minutes of moderate-intensity or 75 minutes of vigorous- intensity aerobic activity per week, or an equivalent amount of mixed moderate-intensity and vigorous-intensity aerobic activity. They should also try to participate in muscle-strengthening activities involving the major muscle groups on two days or more per week.

Cancer survivors who engage in physical activity and exercise can reduce their risks for new chronic diseases, and participation may reduce the adverse effects of cancer treatment. Cancer survivors should consult with their health care providers to verify that their physical activity or exercise plans are consistent with their current physical abilities and health status.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Cancers are disease processes associated with uncontrolled abnormal cell growth and proliferation. Cancers are caused by both internal factors (e.g., heredity, immune dysfunction, abnormal metabolism) and external factors (e.g., behaviors such as smoking and a sedentary lifestyle, radiation exposure). These factors can act alone or in synergy over time to produce carcinogenesis. Common risk factors for most cancers include age, physical inactivity, obesity, heredity, sex, tobacco use, sun exposure, and poor nutrient intake. The risk of colon, breast, bladder, endometrial, esophageal, kidney, and stomach cancer can be reduced by participating in at least 150 minutes of moderate-intensity physical activity per week. More physical activity results in higher risk reduction for breast and colon cancer. Cancer survivors who engage in physical activity and exercise can reduce their risks for new chronic diseases, and participation may reduce the adverse effects of cancer treatment.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY American Cancer Society. 2017. More than 4 in 10 Cancers and

Cancer Deaths Linked to Modifiable Risk Factors (2014). https://www.cancer.org/latest-news/more-than-4-in-10-cancers-

and-cancer-deaths-linked-to-modifiable-risk-factors.html. Accessed 14 October 2018.

American Cancer Society. 2018. Cancer Facts and Figures 2018. https://www.cancer.org/research/cancer-facts-statistics/all- cancer-facts-figures/cancer-facts-figures-2018.html. Accessed 14 October 2018.

American Cancer Society. 2015. Economic Impact of Cancer. https://www.cancer.org/cancer/cancer-basics/economic-impact- of-cancer.html. Accessed 20 October 2018.

Behrens, G., & Leitzmann, M. F. 2013. The Association Between Physical Activity and Renal Cancer:Systematic Review and Meta-analysis. British Journal of Cancer 108(4): 798.

Behrens G, Jochem C, Keimling M, Ricci C, Schmid D, Leitzmann MF. 2014. The association between physical activity and gastroesophageal cancer: Systematic review and meta- analysis. European Journal of Epidemiology 29 (3): 151-170.

Centers for Disease Control and Prevention. 2016. Leading Causes of Death. https://www.cdc.gov/nchs/fastats/leading- causes-of-death.htm. Accessed 14 October 2018.

Friedenreich CM, Cust AE. 2008. Physical activity and breast cancer risk: Impact of timing, type and dose of activity and population subgroup effects. British Journal of Sports Medicine 42: 636-647.

Harris DJ, Atkinson G, Batterham A, George K, Tim Cable N, Reilly T, Haboubi N, Renehan AG, Colorectal Cancer, Lifestyle, Exercise and Research Group. 2009. Lifestyle factors and colorectal cancer risk: A systematic review and meta-analysis of associations with leisure‐time physical activity. Colorectal Disease 11 (7): 689-701.

Keimling M, Behrens G, Schmid D, Jochem C, Leitzmann MF. 2014. The association between physical activity and bladder cancer: Systematic review and meta-analysis. British Journal of Cancer 110 (7): 1862.

Keum N, Ju W, Lee DH, Ding EL, Hsieh CC, Goodman JE, Giovannucci EL. 2014. Leisure‐time physical activity and endometrial cancer risk: Dose–response meta‐analysis of epidemiological studies. International Journal of Cancer 135 (3): 682-694.

Lee IM, Shiroma EJ, Lobelo F, Puska P, Blair SN, Katzmarzyk PT, Lancet Physical Activity Series Working Group. 2012. Effect of physical inactivity on major non-communicable diseases worldwide: An analysis of burden of disease and life expectancy. The Lancet 380 (9838): 219-229.

Liu L, Shi Y, Li T, Qin Q, Yin J, Pang S, Nie S, Wei S. 2016. Leisure time physical activity and cancer risk: Evaluation of the WHO’s recommendation based on 126 high-quality epidemiological studies. British Journal of Sports Medicine 50 (6): 372-378.

McTiernan A. 2008. Mechanisms linking physical activity with cancer. Nature Reviews Cancer 8: 205-211.

National Cancer Institute. 2011. Probability of Breast Cancer in American Women. www.cancer.gov/cancertopics/factsheet/detection/probability- breast-cancer. Accessed 18 October 2018.

National Cancer Institute. 2018a. Cancer Stat Facts. https://seer.cancer.gov/statfacts. Accessed 18 October 2018.

National Cancer Institute. 2018b. Cancer Statistics. https://www.cancer.gov/about-cancer/understanding/statistics Accessed July 16 2019

Rogers CJ, Colbert LH, Greiner JW, Perkins SN, Hursting SD. 2008. Physical activity and cancer prevention: Pathways and targets for intervention. Sports Medicine 38: 271-296.

Singh S, Varayil JE, Devanna S, Murad MH, Iyer PG. 2014. Physical activity is associated with reduced risk of gastric cancer: A systematic review and meta-analysis. Cancer Prevention Research 7 (1): 12-22.

Speck RM, Courneya KS, Masse LC, Duval S, Schmitz KH. 2010. An update of controlled physical activity trials in cancer survivors: A systematic review and meta analysis. Journal of Cancer Survivorship 4: 87-100.

Thune I, Furberg AS. 2001. Physical Activity and Cancer Risk: Dose-Response and Cancer, all sites and site-specific. Medicine & Science in Sports and Exercise 33: S530-S550.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

World Cancer Research Fund International, American Institute for Cancer Research. 2011. Continuous Update Project Report: Food, Nutrition, Physical Activity, and the Prevention of Colorectal Cancer. http://wcrf.org/sites/default/files/Colorectal- Cancer-2011-Report.pdf. Accessed 11 October 2018.

World Health Organization. 2018. Cancer: Key Facts. https://www.who.int/news-room/fact-sheets/detail/cancer. Accessed July 16 2019.

Wu Y, Zhang D, Kang S. 2013. Physical activity and risk of breast cancer: A meta-analysis of prospective studies. Breast Cancer Research and Treatment 137 (3): 869-882.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST

This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.4.2, 2.1.1, 2.2.1, 2.2.3, 2.3.3, 3.2.1, 3.2.2, 6.1.4, 6.1.5, 6.2.1, 6.4.1, 6.4.3

CHAPTER 9 Brain Health

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The prevalence and economic costs of brain and mental health disorders and related health challenges

»  The factors associated with common brain and mental disorders, and how they are generally assessed

»  How physical activity affects cognition, quality of life, depression, anxiety, and sleep

»  The relationship of physiological adaptations to mental health

»  The physical activity guidelines and supporting evidence related to brain health

»  Physical activity recommendations for brain health

OPENING QUESTIONS »  Can regular physical activity have a positive effect on brain

health? If so, how?

»  Can regular participation in physical activity prevent age- related declines in cognitive function and dementia?

»  Can physical activity help improve our quality of life? »  What are the associations among physical activity, mood,

depression and anxiety?

»  Does participation in regular physical activity improve sleep?

»  How much physical activity is consistent with good brain and mental health?

Have you ever noticed that exercising helps you forget about a problem that was causing you a great deal of mental stress, at least for a little while? Do you feel calmer or happier after a visit to the gym? What factors in your life cause you stress? Does regular physical activity and exercise help reduce or control your stress levels? Have you noticed that you tend to focus better in school right after having exercised? Have you ever known someone who was addicted to exercise and noticed the adverse psychological effects of that addiction? All of these questions are related to the relationship between being physically active and good mental health.

Because so much attention has been focused on the physical health benefits of physical activity, we know much less about brain and mental health benefits. Although most people may assume that physical activity enhances mental well-being, evidence of the biological mechanisms that explain the effects of physical activity on

brain health have only begun to emerge more strongly over the past 10 years. The scientific evidence does support the importance of maintaining physical activity for several aspects of brain health, including cognition (e.g., attention or memory) and conditions associated with cognitive decline (e.g., Alzheimer’s), quality of life, mood-related disorders (anxiety, depression), and sleep quality. (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2018). This chapter addresses the concepts related to physical activity and brain health at large, and gives background information on the scientific evidence concerning the relationships between physical activity and brain health.

PREVALENCE AND ECONOMIC COSTS OF BRAIN HEALTH DISORDERS What is brain health and is it the same as mental health? The 2018 Physical Activity Guidelines Advisory Committee adopted the term brain health in preference to mental health. The term brain health encompasses both the behavioral and biological aspects of the brain, as well as the more subjective experiences that result from the brain’s function. Therefore, brain health refers to aspects typically thought of as being part of mental health (i.e., those referring to the mind and its well-being, such as anxiety), as well as to conditions known to result primarily from physical and chemical reactions in the brain (e.g., schizophrenia). When thinking specifically about mental health, we may each have different ideas about the definitions of “good” mental health and “bad” mental health. The World Health Organization (WHO) has defined mental health as a state of well- being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community (WHO 2014).

Brain health as a whole is an essential part of overall health and well-being, and brain and mental disorders or problems can limit

people’s ability to obtain or maintain functional health. The number and types of brain and mental disorders are numerous and their prevalence increases as people age. Such disorders include emotional and behavioral symptoms as described in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (American Psychiatric Association 2013) and the International Classification of Diseases (ICD) (WHO 2018). Common brain and mental health disorders include schizophrenia, dementia, depression, anxiety disorders, substance dependence, and substance abuse. The material in this chapter is limited to common brain and mental health disorders and problems that have been addressed by a strong or emerging body of research in the relevant literature.

Understanding the prevalence of common brain and mental health disorders is difficult largely due to the cultural stigma associated with being diagnosed with these conditions, difficulties people may have in seeking treatment, and differences in assessing the severity of a disorder. Other issues, such as a lack of health insurance, further compound the problem of getting stable national and international estimates of the scope of the problem. The best information available in the United States suggests that common mental health conditions affect 18.3% of American adults in any one year (USDHHS, National Institute of Mental Health [NIMH] 2016). This percentage was the equivalent of 44.7 million Americans in 2016.

Brain and mental health disorders were one of the five most costly medical conditions in the United States from 1996 to 2006 (Soni 2009). The number of people associated with these costs almost doubled from 19.2 million to 36.2 million in 10 years. For Alzheimer’s disease alone, the Alzheimer’s Association estimated health care costs of $259 billion (USD) in 2017. Given the projected population growth patterns for Americans over the age of 65 in the next few decades, it is expected that costs resulting from Alzheimer’s disease and other types of dementia may account for about $758 billion in 2050. Similarly, the total economic costs of major

depressive disorder alone were estimated at $210.5 billion dollars per year in the United States in the year 2000.

The largest component of the economic burden resulting from brain and mental health disorders (50%) is derived from lost work productivity due to depression (Greenberg et al. 2015). In 1990, the estimated economic cost of anxiety disorders in the United States was $46.6 billion, which accounted for 31.5% of the total expenditures for mental illness (Dupont et al. 1996). Obviously, those costs have most likely increased dramatically, although the actual costs in today’s dollars have not been reported.

COMMON BRAIN HEALTH CONDITIONS Following are common brain disorders or problems that have been studied in relation to physical activity:

Cognition and age-related decline in cognitive function Mood disorders Anxiety disorders Psychological distress Low self-esteem Eating or exercise-related disorders Sleep disorders

Basically, cognitive function refers to our ability to think. It broadly encompasses our brain’s ability to process, select, manipulate, or store information. Our ability to perform well at school, to learn new concepts and remember key information, and to stay on task without losing focus are a reflection of good cognitive health.

Age-related decline in cognitive function refers to negative changes that occur over time in the ability to process, select, manipulate, or store information— affecting both behavior and functional ability. Central nervous system (CNS) disorders associated with genetics and aging that have been linked to brain and mental health disorders include multiple sclerosis and dementia

(i.e., a loss of brain function that affects memory, thinking, language, judgment, and behavior—Alzheimer’s and Parkinson’s are considered types of dementia).

Mood disorders include depression, bipolar or manic–depressive disorders, medical conditions related to mood changes, and substance-induced mood disorders (American Psychiatric Association 2013). Depression can be classified as mild (also known as dysthymia) or as major depressive disorder (MDD). Dysthymia, defined as having mild depression symptoms for the past two years, affects 1.5% of the U.S. adult population. In addition, 6.7% of U.S. adults and 12.8% of adolescents (ages 13 to 18) experienced at least one episode of MDD in 2016. Adolescents in the United States have a lifetime combined prevalence of 11.2% for dysthymia and MDD (USDHHS, NIMH 2011, 2017a, 2017,).

The symptoms of depression are diverse and can include difficulty concentrating and making decisions, a loss of interest in hobbies and activities, feelings of hopelessness and helplessness, insomnia, and even thoughts of suicide. The worries that are accompanied by depressive symptoms can also lead to physical symptoms such as fatigue, headaches, muscle tension and aches, trembling, twitching, irritability, sweating, hot flashes, and difficulty swallowing. Depression can leave a person emotionally numb or suicidal, and may be related to other factors such as abuse of alcohol or drugs, phobias, obsessions, and preoccupation with physical challenges. Periodic feelings of mild depression are normal for us all, and can be caused by grief or a medical condition. However, depression or mood disorders that persist beyond two months may indicate major mood change problems.

Anxiety can be broadly defined as a condition of nervousness, uneasiness, or apprehension about a future event or events. Anxiety, although a predictable part of everyday life, over time can become a mental disorder that can hinder daily functional abilities. Anxiety is usually classified as either state anxiety or trait anxiety. State anxiety refers to a person’s existing or current emotional state, and

refers to the type of temporal anxiety (unpleasant feelings) a person experiences when going through specific situations in her life. State anxiety is something that goes away after the situation that provoked it passes by. For example, if a car is about to hit a person while he is crossing the road, he might experience state anxiety. However, this feeling of anxiety goes away once he realizes the car did not hit him and he is safe and can go back to his usual routine. Trait anxiety is specific to a person’s personality and has been described in general as type A (aggressive, high-stress personality) or type B (low-key, low-stress personality). Chronic anxiety disorders can lead to specific phobias, social phobias, panic disorders, obsessive- compulsive disorder, or posttraumatic stress disorders.

Psychological distress refers to mental stressors that are not congruous with good health. Feelings you may have when you are sick or facing medical situations such as surgery are examples of distress. In subjects of exercise studies, psychological distress is often measured subjectively as a lack of well-being. Higher reported levels of well-being are usually associated with a higher quality of life.

Self-esteem refers to feelings of self-worth and value that can influence mental health positively. For example, studies show that people who begin an exercise program may experience higher self- esteem than nonexercisers. Further, more experienced exercisers may maintain higher levels of self-esteem over time if they continue to exercise compared to people who stop exercising. However, if adverse events such as injury or the adoption of addictive behaviors (e.g., compulsive running, exercise addiction, disordered eating) occur, self-esteem levels may drop or become inconsistent with good mental health. Other addictive behaviors that are associated with lower levels of mental health are anorexia nervosa (limiting food intake and becoming excessively lean), bulimia (bingeing and purging), and muscle dysmorphia (a preoccupation with muscularity).

Sleep disorders refer to alterations in the way one sleeps that affect health and quality of life. Sleep disorders include insomnia (difficulty sleeping at night), sleep apnea (abnormal breathing patterns while sleeping), restless legs syndrome (a sleep movement disorder characterized by the urge to move one’s legs while trying to fall asleep), narcolepsy (extreme sleepiness during the day), and many others.

RISK FACTORS ASSOCIATED WITH BRAIN HEALTH DISORDERS A full review of the risks associated with brain health disorders is beyond the scope of this text; however, descriptions of some of the risk factors associated with common brain health are provided here. Many brain health disorders are associated with sedentary lifestyles or low levels of physical activity.

Numerous risk factors are associated with brain and mental disorders. Although each disorder has its own unique risk factors, several consistent themes appear across major mental health diagnoses. Modifiable Risk Factors for Brain and Mental Health Disorders

Physical inactivity Substance abuse (including alcohol) Low self-esteem Distress Negative lifestyle behaviors

Nonmodifiable Risk Factors for Brain and Mental Health Disorders

Age Sex Heredity (genetics) Undergoing traumatic experiences

Chronic medical conditions

Following are descriptions of the modifiable and nonmodifiable risk factors for mental disorders:

• Physical inactivity. For some brain health conditions, a certain amount of physical activity appears to be very helpful, although too much exercise may aggravate existing mental health problems.

• Substance abuse. The abuse of any legal or illegal substance, particularly over a period of years, can lead to brain and mental health disorders.

• Low self-esteem. Negative feelings of one’s capabilities, goals, accomplishments, place in the world, and relationships with others can have a major effect on mental health.

• Distress. Perceptions of the various stressors in life and the ability to cope with them can positively or negatively affect the function of the central nervous system (CNS) and the adoption of positive or negative health behaviors.

• Negative lifestyle behaviors. Overcoming negative lifestyle behaviors by adopting positive ones can improve mental health.

• Age. Many brain health disorders (e.g., major depressive disorder) are more commonly seen in younger adults; older adults appear to be less affected, with the exception of those who become challenged to maintain their functional health.

• Sex. Women are at a higher risk for various brain and mental health disorders (e.g., major depressive disorder) than men.

• Heredity (genetics). A family history of brain health disorders may predispose a person to these conditions.

• Traumatic experiences and medical conditions. Traumatic experiences and poor health conditions are known risk factors for brain and mental disorders, most of which are nonmodifiable by the individual. Previous suicidal thoughts are also a nonmodifiable risk factor for future episodes. Age, self-esteem, genetics, and current health status all affect how people cope with life stresses, how they

cope with the risk of suicidal thoughts, and how they respond to medical treatments such as surgery and mental health therapy.

PHYSICAL ACTIVITY AND BRAIN HEALTH Prior to a discussion of the physiological mechanisms that may explain the observed relationship between physical activity and some brain health disorders, it is helpful to conceptualize the breadth of work in the area. Perhaps more than any other health outcome in this text, the bulk of the scientific work related to physical activity and brain health has addressed physical activity as a possible treatment for the disorder. For example, does an exercise program improve the sense of well-being among people diagnosed with trait anxiety? How much improvement might be expected? How long will the improvement last? Does it depend on the dose (i.e., the amount) of physical activity? Can physical activity have an additive effect in an existing treatment regimen—that is, can physical activity or exercise improve the effects of a standard treatment for a brain health disorder?

These questions do not address the issue of whether physical activity can prevent some brain health disorders from occurring at all. Clearly, preventing a disease is preferable to treating it once it has been diagnosed (this is a central tenet of public health). However, less research has been conducted on the preventive role of physical activity in brain health disorders. Dunn and Jewell (2010) created a useful framework for conceptualizing existing (and future) studies of physical activity as a treatment modality for mental health disorders. This framework takes into account the three ways exercise and physical activity may be used with people that already have a brain or mental health disorder: as a monotherapy (i.e., the sole treatment under investigation), as an augmentation therapy (i.e., to add to existing treatments such as prescription drugs), or as an adjunct therapy (i.e., having health benefits other than helping to treat the disease). These three distinctive types are then placed into a 3-by-3 table with the following lengths of effects: acute (short-term) effects

(the kind one might see with a standard laboratory-based exercise training study), continuation effects (moderate-term effects that might be expected when patients begin to exercise on their own), and maintenance effects (longer-term effects that might signify the effectiveness of the physical activity behavior in controlling the condition under study).

The framework in figure 9.1 is particularly useful because it helps us explore and categorize the physiological and behavioral effects that may be at work as mechanisms for any associations between physical activity and brain or mental health outcomes. Acute exercise-related adaptations are most likely to be initially apparent in short-term training studies. The extent of physiological adaptations, as with other health outcomes, are likely dose dependent—that is, higher doses and intensities of physical activity result in greater physiological changes (see chapter 2). These adaptations should remain with a continued dose of exercise into the continuation and maintenance periods, but behavioral changes should also be apparent as the exercise training theoretically evolves into a physically active lifestyle.

Figure 9.1   Framework for the conceptualization of scientific research on physical activity and brain health. Based on Dunn and Jewell (2010).

What physiological adaptations resulting from physical activity may explain the association with some brain health disorders? As noted in previous chapters, even moderate-intensity physical activity results in improvements in strength and muscular endurance, O2max, force, and power in most previously sedentary people. The extent of these adaptations can be expected to correlate closely with the dose of exercise: The higher the dose and the more intense the physical activity, the greater the physiological response. To understand the impact of these changes, we must also understand their effects on the brain and nervous system—the center of most mental health disorders.

The physiological adaptations that result from physical activity have been shown to improve cerebral capillary growth and development (also called angiogenesis), brain blood flow, and oxygenation. A popular hypothesis is that this increase in cerebral blood flow increases cerebral metabolism, and that this increased cerebral activity (particularly in older adults) may be partially

responsible for a protective effect of physical activity against mental health disorders (Deslandes et al. 2009). Other related hypotheses include the notion that exercise improves the regulation of neurotransmitters (i.e., chemical substances that assist in the transfer of nerve impulses across synapses), the growth and maintenance of brain nerve cells, and the ability of nerves to conduct impulses across synapses.

Somewhat distally related to the physiologic adaptations are the biomechanical improvements that result from physical activity. Biomechanically, people can expect to see improved economy or efficiency (i.e., reduced energy cost at a given workload) after aerobic and musculoskeletal strengthening activities. Improvements in balance, stability, mobility (flexibility and range of motion), and peripheral proprioception (i.e., sense of position and movement) can also help people develop or maintain positive levels of self-esteem and well-being. The central hypothesis is that the development of motor skills allows people to participate in a greater variety of physical activity and exercise activities with more confidence, and that these increases in self-efficacy can result in positive changes in mental health for some people.

Regular physical activity has measurable and substantial positive effects on mental health.

How intense does physical activity need to be to have an effect on these physiological markers of brain health? The answer certainly varies with the marker, but the best evidence from neurobiology studies is that light physical activity (strolling, performing activities of daily living) is not enough to elicit the necessary physiological responses. The physical activity must be ≥3.0 METs (i.e., moderate or vigorous intensity; see chapter 2) to generate the physiological stimulus necessary to promote mental health.

PHYSICAL ACTIVITY AND BRAIN COGNITIVE FUNCTION Physical activity may also affect brain cognitive function in people without any diagnosed brain health disorder. Many have wondered: Can physical activity make us smarter or help us remember things for longer? Do people who are more physically active have better cognitive function than similar, but inactive people? Do physically active children do better in school than inactive children? Clearly,

these questions are associated with brain health because compromised brain cognitive function may be a subclinical precursor to more serious mental disorders.

Brain cognitive function outcomes that researchers have investigated for an association with physical activity are shown in figure 9.2. This is not an exhaustive list, and studies have varied from single-bout exercise studies to short-term training studies. The topics highlighted in this figure are some of the most promising areas of current research in this field. The 2018 Physical Activity Guidelines Advisory Committee Report concluded that there is strong evidence demonstrating that short bouts of exercise have a transient benefit for cognition (i.e., it only lasts for a brief amount of time after performing the exercise), which includes improvements in attention, memory, and processing speed. Studies have shown that stronger effects occur among young children (prepuberty) and among older adults. This is probably why some teachers or parents report that their student or child tends to be more attentive or to learn more effectively just after having engaged in active play for a short while. It is important to note that strong evidence currently exists of these positive effects on conditions for short bouts of exercise only (as compared to longer duration bouts), but it does not mean that that longer bouts of exercise would not be equally beneficial. This is simply an artifact of the way in which the experiments have been performed: Investigators asked study participants to perform short bouts of exercise, then measured these aspects of cognition immediately after. More research examining the effects of sustained and regular physical activity on cognitive outcomes is needed.

TESTING FOR BRAIN AND MENTAL HEALTH DISORDERS Tests to evaluate, diagnose, and treat brain and mental health disorders are typically conducted by physicians or researchers with expertise in the area. Screening tests

(to identify cases to refer for more extensive diagnostic workups) are often used as the first step in evaluating mental health disorders. These tests range from self- administered questionnaires to in-person evaluations and observation studies. An example of a simple mood disorder screening assessment is the Profile of Mood States (POMS), which is a questionnaire-type instrument that assesses fluctuating mood states on key markers such as tension- anxiety, anger-hostility, fatigue, inertia, vigor- activity, and confusion-bewilderment. The POMS has been used in a variety of clinical mental health settings including those involving the relationships between physical activity and exercise interventions or participation levels.

Cognitive function declines rapidly in older adults. With populations in developed countries aging rapidly, questions of how physical activity and exercise affect brain function become extremely important as we seek to keep our parents and grandparents functionally independent and mentally healthy for as long as possible. There is strong evidence demonstrating that regular physical activity helps prevent age-related cognitive decline, including preventing the development of dementia, and in particular Alzheimer’s disease. It is estimated that globally, 13% of all cases of Alzheimer’s are a result of physical inactivity. In the United States, this estimate is 21%. Thus, regular participation in physical activity could be an effective strategy to prevent numerous cases of this condition.

Figure 9.2   Brain function outcomes in youth and adults that have been investigated for associations with physical activity and exercise.

PHYSICAL ACTIVITY, SLEEP, AND QUALITY OF LIFE Quality of life can be broadly defined as one’s satisfaction with life. Feeling satisfied with life—including feelings of accomplishment, lack of stress, and overall happiness—constitutes an important component of mental health. The broad term quality of life includes aspects related to physical and mental health as well as aspects that go beyond health, such as economic well-being. Figure 9.3 shows the main concepts included under the umbrella of quality of life. Quality of life is known to be associated with several health and well- being outcomes. As such, many have wondered if leading a physically active lifestyle helps us achieve better quality of life. There is strong evidence demonstrating that higher amounts of regular physical activity are associated with positive perceptions of one’s quality of life. For older adults in particular, physical activity can contribute to improving health-related quality of life, in part, by helping them maintain their physical function and independent

mobility, which in turn leads to better perceptions of their health- related quality of life (USDHHS, PAGAC 2018).

Recent years have also seen a substantial increase in the amount of research studies documenting the effects of physical activity on sleep disorders and sleep quality at large. There is sufficient evidence showing that physical activity, through acute bouts as well as regular bouts of physical activity, can improve several sleep outcomes among adults. In particular, acute bouts of physical activity can help improve onset latency (how fast you are able to fall asleep), total sleep time, and how fast you can wake up in the morning. Meanwhile, being physically active on a regular basis can help in achieving a better quality sleep (USDHHS, PAGAC 2018).

Figure 9.3   Physical and mental health under the umbrella of quality of life. From USDHHS, PAGAC (2018).

PHYSICAL ACTIVITY AND DEPRESSION AND MOOD DISORDERS One may also wonder if physical activity can help prevent or manage certain mood-related conditions such as anxiety or clinical depression. More specifically, the evidence shows that anxiety is reduced when performing short, acute bouts of exercise. The reduction in anxiety as a result of these acute bouts of activity occurs in the period of time immediately after the exercise took place. This may be why you sometimes feel like going for a run or swimming a few laps when you are feeling overly anxious or stressed. In terms of depressive mood symptoms and clinical depression, it has been found that regular physical activity can help reduce the risk of developing depression. Now it is also known that physical activity

can help reduce the symptoms of depression among people that have already been diagnosed with major depression.

PHYSICAL ACTIVITY GUIDELINES FOR BRAIN HEALTH Scientific evidence supports the assertion that physical activity lowers the risk of (1) dementia including Alzheimer’s disease, (2) anxiety symptoms, (3) anxiety disorders, (4) depressive symptoms, (5) major depressive disorder, and (6) age-related decline in cognitive function. There is moderate evidence suggesting that physical activity interventions may constitute an effective treatment for improving cognitive function among people with dementia, including Alzheimer’s disease, and other disorders that impair cognitive function, such as ADHD or Parkinson’s disease. Physical activity is recommended only as an adjunct therapy to other treatment modalities (Blake 2012).

Figure 9.4   Physical activity and feelings of distress—prospective cohort studies 1995-2007. Adapted from USDHHS, PAGAC (2008, G8-7).

Figure 9.4 is a summary of recent research on the dose-response relationship between physical activity and exercise and feelings of distress. As shown, modest levels of physical activity (as compared to lower levels of physical activity) are associated with significantly lower odds of distress, or higher odds of well-being. The data in this figure provide more evidence of the public health benefits of physical activity; the brain health benefits are not limited only to athletes and people who exercise at the highest levels.

How does participation in physical activity help maintain or improve self-esteem?

Although scientific evidence through extensive research on the health benefits of physical activity and exercise on many physical health outcomes exist, only since the 1980s have positive relationships between physical activity and brain health begun to emerge in the literature. The development of new exercise science technologies and techniques along with the greater public health emphasis on the management of brain and mental health disorders should help us optimize physical activity and exercise interventions for those with mental health disorders.

SCIENTIFIC EVIDENCE

The 2018 PAGAC noted strong scientific evidence that physical activity has positive effects on four major components of brain health: cognitive function (including improved memory and attention in prepubertal children and older adults, and risk reduction for dementia and Alzheimer’s), quality of life, mood disorders (including depression and anxiety), and sleep (including onset latency, total sleeping time, wake time after sleep, and overall sleep quality) (USDHHS, PAGAC 2018).

Participation in regular physical activity and exercise can lower the risk for depression, distress and lack of well-being, and dementia by 20 to 30%. Risk reduction for men and women appears to be similar, and there is limited evidence that blacks, Hispanics, and white Caucasians benefit alike.

The dose of physical activity or exercise needed to reduce the risk of dementia (including Alzheimer’s), and to ameliorate mental health disorders (e.g., depression and distress) is three to five days per week of 30- to 60-minute sessions of moderate-to-vigorous activities (moderate evidence). Scientific evidence of a dose-response relationship between physical activity and exercise, lessened anxiety, and improved sleep patterns is currently insufficient.

There is some scientific evidence that physical activity or exercise may reduce the onset, progression, or adverse impact of central nervous system (CNS) disorders such as multiple sclerosis and Parkinson’s disease.

LEADER PROFILE James (Jim) Sallis, PhD

Why and how did you get into the field of Physical Activity and Public Health? I have always been interested in staying healthy—even as a teen, my pediatrician pronounced me fit. I would ask, “Is there anything I should do to stay healthy?” He told me, “No, you’re fine.” I did not find that satisfactory. Today that would be close to malpractice, but things were different in the early 1960s. For some reason, I had an early recognition of the importance of preventing problems.

When I was in graduate school studying psychology, my intention was to help people be mentally healthy. But at that time the fields of behavioral medicine and health psychology were coming into existence, and those subject areas resonated with my personal interest in staying healthy, so I decided to shift my focus to physical health. I was fortunate to be accepted into a clinical psychology internship program at Brown University, which was a major center (then and now) for behavioral medicine. This was 1980, just after the publication of Ralph Paffenbarger’s landmark papers on physical activity and health. Mass media covered the “fitness revolution,” and I decided to become more active. One of my supervisors, Michael Follick, happened to mention to me, “There might be something to this exercise thing. It could be worth studying.” For some reason that hit me like a bolt of lightning. It changed the course of my life because I decided to apply for a postdoc with the Stanford Five-City Project. Stanford University was (and is) a major center for physical activity research, with Ralph Paffenbarger, Bill Haskell, and Peter Wood being among the leaders.

Fortunately, I was able to secure a postdoc, and it set the course for my career.

Did any one person have a major influence on your career? How? While I have had several influential mentors and learned from many phenomenal and generous people, I want to single out Bill Haskell. He helped me develop the ideas for my first papers on physical activity and guided me in the analysis and writing of them. Bill and everyone else on the team at Stanford were extremely gracious in letting me write several papers using Five-City Project data. I’m sure it was Bill who recommended me to attend the very first conference on physical activity and public health. It was organized by Ken Powell at the Centers for Disease Control and Prevention (CDC) in 1983. At the meeting in Atlanta, I met many leaders and soon-to-be leaders in this new field, creating an instant network with colleagues that grew into friendships. The meeting centered around discussions of initial drafts of papers that attempted to define this new field, and I was invited to coauthor two

of them. The resulting special issue in Public Health Reports in 1985 was a seminal publication that played a large part in my transition from complete unknown to being associated with the leaders. So, I am grateful to Bill for giving me that golden opportunity.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My interests for the past 20 years have been performing research to understand how environments and policies affect physical activity for good or ill, and encouraging others to study these big questions. It became obvious to me that some places are designed to make physical activity pleasant, fun, and safe, and some places are designed to achieve the opposite. In the United States, it seems like much more effort and money has been devoted to the latter. Thus, I believe we will not make an effect on physical activity until we invest more in excellent sidewalks and safe bicycle facilities, reduce spending on roads, ensure every neighborhood has parks and playgrounds designed for people to do multiple activities, provide physical

activity throughout the day at schools and early care and education settings, and change zoning laws to require more walkable neighborhood designs.

In my training I was taught nothing about how to communicate research findings to the people who can use them to improve practice and policy. Over the years I have learned to write research briefs in lay language, develop relationships with decision makers in a wide range of fields, present at practitioner conferences, find opportunities to meet directly with decision makers including elected officials, and work closely with advocacy groups who have expertise in using research to inform practice and policy. Though these activities are rarely encouraged by universities, research translation activities have been extremely rewarding.

Why do you do what you do? I work in physical activity because it is one of the world’s most important public health problems, and it is receiving too little attention and stimulating too little action to improve the situation. I want to use my time and energy to research what I consider to be meaningful topics and use the results to make as big a positive impact as possible.

What are two key issues that must be addressed by 2030? The biggest problem in the field of physical activity and public health is the persistently low level of funding for research, programs, and policy advocacy. Physical activity is a low priority in every public agency I am aware of, resulting in inadequate funding. I do not have an answer about how to increase funding by government, non- governmental organizations, foundations, or private business, so solving this problem will be the challenge for the next generation.

Creative research has generated many intervention strategies with evidence of effectiveness, yet virtually none of these interventions are routinely implemented in the United States or elsewhere. A big reason for this failure is the problem I just previously described. We must develop strategies for implementing evidence-based intervention strategies, aimed at supporting individuals, improving environments, and changing policies, that reach all members of the population on an equitable basis.

GUIDELINES The 2018 Physical Activity Guidelines Advisory Committee Scientific Report presents substantial evidence demonstrating that physically active adults have a lower risk of depression and cognitive decline (i.e., decline in thinking, learning, and judgment skills, and reduced risk of dementia including Alzheimer’s disease). Physical activity also improves quality of sleep as well as quality of life, and acute bouts of physical activity have positive effects on anxiety. Among children and older adults, acute bouts of physical activity positively contribute to better memory and attention. Brain health benefits have been found in people who do aerobic activities or a combination of aerobic and muscle-strengthening activities three to five days per week for 30 to 60 minutes at a time.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Brain and mental health conditions have been estimated to affect 18.3% of American adults in any one year, and the relative increase in medical expenditures for mental disorders rose from $35.2 billion in 1996 (in 2006 U.S. dollars) to $57.5 billion in 2006. Common brain health disorders include dementia, depression, bipolar or manic-depressive disorders, medical conditions related to mood changes, substance-induced mood disorders, anxiety, phobias, panic disorders, obsessive- compulsive disorder, posttraumatic stress disorders, feelings of distress, CNS dysfunctions, and addictive behaviors. Common risk factors for brain health conditions include physical inactivity, poor self-esteem, distress, drug abuse,

alcohol abuse, negative lifestyle behaviors, age, sex, suicidal thoughts, and medical treatments. Tests to detect brain health disorders are typically conducted by physicians (general practitioners) and specialists (psychiatrics and sleep study experts). Brain health benefits have been found in people who do aerobic activities or a combination of aerobic and muscle- strengthening activities three to five days per week for 30 to 60 minutes at a time.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Alzheimer’s Association. 2017. Alzheimer’s disease facts and

figures. Alzheimer’s and Dementia 13: 325-373. www.alz.org/documents_custom/2017-facts-and-figures.pdf.

American Psychiatric Association. 2013. Diagnostic and Statistical Manual of Mental Disorders: DSM-V, 5th ed. Washington, DC: American Psychiatric Association.

Blake, H. 2012. Physical Activity and Exercise in the Treatment of Depression. Frontiers in Psychiatry 3: 106.

Deslandes A, Moraes H, Ferreira C, et al. 2009. Exercise and mental health: Many reasons to move. Neuropsychobiology 59: 191-198.

Dunn AL, Jewell JS. 2010. The effect of exercise on mental health. Current Sports Medicine Reports 9: 202-207.

DuPont RL, Rice DP, Miller LS, Shiraki SS, Rowland CR, Harwood HJ. 1996. Economic costs of anxiety disorders. Anxiety 2 (4): 167-172.

Greenberg P, Fournier AA, Sisitsky T, Pike CT, Kessler RC. 2015. The economic burden of adults with major depressive disorder in the United States (2005 and 2010). Journal of Clinical Psychiatry 76 (2): 155-162.

Soni A. 2009. The five most costly conditions, 1996 and 2006: Estimates for the U.S. civilian noninstitutionalized population. Statistical brief #248. Rockville, MD: Agency for Healthcare Research and Quality. www.meps.ahrq.gov/mepsweb/data_files/publications/st248/sta t248.pdf. Accessed 23 September 2011.

U.S. Department of Health and Human Services, National Institute of Mental Health. 2011. Statistics: Dysthymic Disorder Among Children. www.nimh.nih.gov/health/statistics/prevalence/dysthymic- disorder-among-children.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Institute of Mental Health. 2016. Statistics: Mental Illness. www.nimh.nih.gov/health/statistics/mental-illness.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Institute of Mental Health. 2017a. Statistics: Major Depression. www.nimh.nih.gov/health/statistics/major-depression.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, National Institute of Mental Health. 2017b. Statistics: Persistent Depressive Disorder (Dysthymic Disorder). www.nimh.nih.gov/health/statistics/persistent-depressive- disorder-dysthymic-disorder.shtml. Accessed 31 October 2018.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity

Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

World Health Organization. 2014. Mental Health: A State of Well- Being. www.who.int/features/factfiles/mental_health/en. Accessed 31 October 2018.

World Health Organization. 2018. International Classification of Diseases. www.who.int/classifications/icd/en. Accessed 31 October 2018.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.4.2, 2.1.1, 2.2.2, 2.3.3, 3.2.1, 3.2.2, 6.2.1, 6.4.1, 6.4.3

CHAPTER 10 Health Risks of Exercise and Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The primary health risks associated with exercise and physical activity

»  Common musculoskeletal injuries associated with physical activity

»  Risk factors for exercise-related musculoskeletal injuries »  Exercise-related sudden cardiac death and the factors that

predict its occurrence

OPENING QUESTIONS »  What are the risk factors for exercise-related

musculoskeletal injuries?

»  Can these injuries be prevented? »  Does exercise cause sudden cardiac death or heart attacks? »  Do the benefits of physical activity and exercise outweigh

the risks?

»  Must someone consult a physician prior to beginning to exercise?

Throughout part II, the emphasis has been on the role physical activity plays in improving and promoting health. Physical activity lowers the risks of heart disease, some cancers, and diabetes; improves the musculoskeletal system; and prevents bone diseases. It improves quality of life and some mental health disorders. The benefits of physical activity are remarkable, particularly its ability to lower the risks of chronic diseases, and new research continues to teach us about these, and other, positive outcomes. But does physical activity also have a downside? Can participating in physical activity and exercise actually increase the risk of certain conditions? If so, do the benefits of being physically active outweigh the risks?

In public health, it is important to understand not only the health benefits of a certain behavior or intervention you may be promoting, but also the risks. Knowledge of a downside to any program is critical to having a complete picture. Vaccination programs, environmental changes for cleaner air, educational programs for HIV prevention—all of these are examples of situations where programs with good intentions might have unintended risks to people and populations you are targeting. Understanding the risks as well as the benefits of particular programs is practicing “responsible” public health.

Two primary unintended consequences (risks) of physical activity that have been extensively studied are musculoskeletal injury and exertion-related sudden cardiac death. In this chapter, we review these risks and put them in perspective in terms of the costs and benefits of increasing physical activity.

MUSCULOSKELETAL INJURIES A physical activity–related musculoskeletal injury involves some type of acute disorder in a bone, muscle, joint, or connective tissue that is attributable to physical activity or exercise. Such injuries can occur suddenly, such as an ankle sprain, or over a period of exposure, such as a gradual pain in the shoulder of an electrician who frequently works over his head installing circuits. Ligament tears, sprains, strains, bone fractures, bruises, and joint dislocations are common musculoskeletal injuries that can result from physical activity and exercise. Clearly, such injuries can occur without physical activity (e.g., in a motor vehicle accident), but this chapter addresses only those that result from some type of body movement.

A difficult problem when studying musculoskeletal injuries involves the definition of injury. What qualifies as an injury? You probably know what an injury means to you, but does your mother have the same definition? How about a world-class sprinter or a heavy machine operator? Chances are that each person has a unique idea of what an injury is. Many times it involves pain, loss of function, and an inability to work or socialize. Some people have a higher threshold for pain than others do, so the same incident in two people may be classified as an injury by one person and a “bump” by the other.

Severity is also an issue. How long does the pain or loss of physical function have to last before the incident is called an injury? Thirty minutes? Thirty days? Must a person see a physician or other health care professional before an incident can be classified as an injury? What if that person does not have health insurance? Surely someone without health insurance would be less likely to see a

doctor or health care professional for an injury than someone with insurance and the same injury. This could result in a study or survey counting one occurrence but not the other, simply because the latter could not be “found.” Does someone have to be injured during an exercise session for the injury to be considered exercise related, or does an injury caused by cumulative exposure to exercise (e.g., arthritis in the knee) also count as an exercise-related injury?

DEFINITION OF INJURY What type of exercise-related musculoskeletal injury would be severe enough for you to report it on a survey? Would you be able to remember a sore back after doing a day’s worth of gardening six months ago? Studies of musculoskeletal injury are limited because of the lack of a standardized definition of what constitutes an injury and the variability in the recall of study respondents.

The point is that, although the scientific literature is replete with studies that have examined musculoskeletal injuries as related to physical activity and exercise, a consistent definition has rarely been used. This makes comparing studies nearly impossible. Studies that rely on participants’ self-reports of “any injury” are not comparable to those that require a doctor’s diagnosis prior to being classified as an injury. What we know about the rates and risks of musculoskeletal injuries due to physical activity and exercise is therefore limited compared to the wealth of information available on the health benefits.

What is the incidence of exercise-related injury? This simple question, unfortunately, does not have a simple answer because of many complications. First, as discussed, the definition of injury is varied. Most people would count an event that was serious enough to require a trip to an emergency room, but what about something less serious? Is an event that requires you to take a few days off

work, but not a trip to the emergency room, serious enough to be considered an injury? What about simply taking a few aspirin and self-treating for a few days? The main limitation to studies of physical activity and musculoskeletal injury is the use of inconsistent (and incomplete) definitions.

NUMERATOR MONSTER Studies of exercise-related injuries are particularly

prone to the numerator monster. This problem arises when injuries are counted, but the population at risk (the denominator) is ignored. Epidemiologists rely on the number of cases (numerator) as well as the size of the population at risk (denominator) to calculate prevalence and incidence. If one or the other is not known, it is impossible to compare types of activity and their respective risks for musculoskeletal injury. For example, if 100 walkers and 100 rugby players (both numerators) showed up at an emergency room one weekend for treatment of exercise-related injuries, one might say that the activities are equally dangerous. This assumption would be incorrect, however. There are many more walkers than there are rugby players in a community. Without taking into account the difference in size between the populations at risk (the entire group of walkers and the entire group of rugby players), one would miss the fact that rugby players are much more likely to be injured than are walkers. Beware of the numerator monster.

Another complicating factor in determining the prevalence of exercise-related injury is the fact that different types of physical activity have different participation rates and may result in different types of injury. Low-impact and noncontact exercise activities and sports are likely less risky for musculoskeletal injury than are high- impact and contact sports. These differences make it somewhat meaningless to discuss the prevalence of injuries in the same manner we talk about the prevalence of diabetes or myocardial

infarction, both of which are single diagnoses. Similarly, we expect weight-bearing activities such as walking or running to be associated with injuries of the lower extremities more often than other parts of the body. Racket sports such as tennis and squash may be more likely to result in injuries of the upper extremities (shoulders and arms) or the head (from being struck by a racket or a ball).

Finally, in the United States there are no routine surveys or systems from which to generate a picture of exercise-related injuries. There have been periodic studies (Powell et al. 1998), studies of catastrophic injuries (Mueller and Cantu 1991), and studies that focus on numerators (Gotsch et al. 2002), but none of these have tracked these problems over time. This situation obviously makes it impossible to truly understand the risks of physical activity, which limits public health professionals’ ability to give an accurate risk/benefit assessment.

Although population-based exercise-related prevalence data are limited, we do know some things about what might be expected to occur for several types of physical activity in a defined time period. The data in table 10.1 are from a national survey of injury (Powell et al. 1998). By asking respondents what they were doing when they became injured, the investigators were able to compare various types of common physical activities. Obviously, each of the reported activities is fairly safe; fewer than 3 people out of 100 were injured in any 30-day period. Outdoor bicycle riding appears to be the least risky activity in terms of musculoskeletal injury, and weightlifting was the riskiest.

Although these findings may appear to be intuitive, they emphasize the need to quantify the risks of physical activity for application in the real world. For example, such information can be very useful to a program manager who is beginning a community- based walking program for sedentary adults. After reviewing the data in table 10.1, the manager now knows that she might expect one or two people in her program to be injured during the walking program in a given month (30-day period). This is useful information for

program planning and evaluation. If she puts appropriate preventive strategies in place and none of her participants become injured, she can report that the participants in her program are injured less frequently than what one might expect given the literature.

Despite the problems in the scientific literature, we do know some things about the causes and risk factors for physical activity–related musculoskeletal injuries. These factors have been identified in the scientific literature from studies in epidemiology, biomechanics, physiology, and medicine. As with other health-related outcomes for physical activity and exercise, risk factors can be conveniently classified as modifiable (i.e., things that can change or be changed) and nonmodifiable (i.e., things that typically can’t be changed or are difficult to change).

Table 10.1   Percentage of Participants Reporting a Musculoskeletal Injury by Type of Physical Activity

Type of physical activity Percentage injured in 30 days

Aerobics or aerobic dance 1.4

Gardening or yard work 1.6

Bicycle riding (outdoors) 0.9

Walking for exercise 1.4

Weightlifting 2.4

Adapted from Powell et al. (1998).

Modifiable Risk Factors for Musculoskeletal Injuries

Amount and type of current physical activity Cigarette smoking Low physical fitness level Improper use of protective equipment Adverse environmental conditions

Nonmodifiable Risk Factors for Musculoskeletal Injuries

Age

Sex (for some types of injury) History of injury Amount of physical activity in the past (history) Anatomical factors Environmental, or external, conditions

Following are descriptions of the modifiable and nonmodifiable risk factors for musculoskeletal injury:

• Amount and type of current physical activity. The more physical activity a person performs, the higher the risk of musculoskeletal injury associated with the activity. This finding has been demonstrated repeatedly in the literature. Moreover, different types of physical activity and exercise convey different risks. For example, contact sports are more likely to be related to injury than noncontact sports.

• Cigarette smoking. Although exercise and cigarette smoking would appear contradictory behaviors, people whose occupations demand physical activity, such as construction workers and landscapers, may also smoke. Cigarette smoking seems to increase the risk of physical activity–related musculoskeletal injuries, possibly as a result of vasoconstriction, which restricts the amount of oxygen being delivered to the muscles or connective tissues. The structure of the site and the availability of metabolic nutrients are then altered, and the hypothesis is that this alteration makes the muscle or connective tissue more susceptible to injury.

• Low physical fitness level. People who have higher physical fitness levels (measured as O2max) have been consistently shown to be at lower risk of musculoskeletal injury related to physical activity.

• Improper use of protective equipment. Bicycle helmets, protective padding for skateboarders, breakaway bases for baseball players, mouthguards for certain sports, shoes—all of these are

examples of protective equipment that, when properly used, can prevent musculoskeletal injuries associated with physical activity.

• Adverse environmental conditions. Environmental conditions can be considered either nonmodifiable or modifiable. If conditions are not conducive to physical activity or could increase the risk of injury during physical activity, venues can be changed, activities can be rescheduled, or the type of physical activity can be modified (e.g., going to the gym rather than playing basketball in the rain).

• Age. Changes in the musculoskeletal system that occur with aging result in older people being more likely to be injured than younger people doing the same activity.

• Sex. Women’s skeletal structure and sex hormones have been hypothesized to increase their risk of lower extremity injury (specifically, to the anterior cruciate ligament in the knee) compared to men doing the same activities.

• History of injury. A history of injury is one of the most consistent risk factors for injury during physical activity reported in the literature. People who have been injured previously are more likely to be injured in the future than those who have not. This is a strong rationale for efforts to prevent injuries from occurring in the first place.

• Amount of physical activity in the past (history). Much of what we know in the area of physical activity and musculoskeletal injury comes from studies of military recruits who participate in basic training involving substantial physical activity. Recruits who were physically active prior to the training were less likely to be injured during the training. Again, this finding makes a powerful case for injury prevention.

• Anatomical factors. Each human body is unique, and a person’s biomechanical and anatomical characteristics may increase the risk of an (or exacerbate an existing) exercise-related musculoskeletal injury. Among the many factors that have been hypothesized are varus, or bowlegs (an abnormal inward angle of a bone); valgus, or

knock-knees (an abnormal outward angle of a bone); pes cavus (an abnormally high foot arch); and pes planovalgus (flat feet). Many anatomical problems can be reversed through medical intervention.

• Environmental, or external, conditions. A frequently overlooked risk factor for exercise-related musculoskeletal injuries is environmental conditions. Traffic, damaged or wet playing fields or courts, and broken sidewalks are all examples of environmental, or external, conditions that could increase the risk of a musculoskeletal injury associated with physical activity.

Figure 10.1   Rates of exercise-related musculoskeletal injuries for men and women. Adapted from Hootman et al. (2001).

KINESIOLOGY AND MUSCULOSKELETAL INJURIES The scientific literature fairly consistently reports a dose-response relationship between the risk of musculoskeletal injury and the overall dose (or volume) of physical activity. The results come from studies of runners and walkers (Macera et al. 1989) and military recruits (Almeida et al. 1999). Quite simply, the more physical activity you do, the higher your risk of musculoskeletal injury. The dose of

physical activity, as we learned in chapter 2, is related to frequency, intensity, and duration.

Physical activity can increase the risk of adverse events such as musculoskeletal injuries or sudden cardiac death. Do the benefits of participating in regular physical activity outweigh the risks?

The type of physical activity can also influence the risk of injury. Low-impact weight-bearing activities (e.g., walking) or non-weight- bearing activities (e.g., swimming laps, cycling) are thought to be associated with the fewest musculoskeletal injuries related to physical activity. In contrast, running and sport participation (particularly contact sports) may carry a much higher risk of injury. This difference is thought to operate through greater stresses on connective tissue and higher-impact forces on bones and joints. In a study conducted by Hootman and colleagues in 2001, people who reported participating in sports had nearly twice the risk of activity- related injury compared to nonexercisers (see figure 10.1).

Among people who play sports, collision sports (ice hockey, American football, rugby) or contact sports (basketball, soccer) carry a higher risk of injury than limited-contact sports (baseball) and

noncontact sports (cycling, racewalking). These results come from multiple surveys, each with its own definition of injury.

An interesting line of research has emerged regarding physical activity and risk of musculoskeletal injuries. Although higher doses of physical activity appear to be related to a higher acute risk of injury associated with that activity, could it be that the overall risk of being injured (both exercise- and nonexercise-related musculoskeletal injuries) shows an overall decrease with increased physical activity? This would seem an important overall health question, particularly for older adults who are susceptible to injury as a result of falls.

Carlson and colleagues (2006) examined this question in a study of more than 96,000 adults in the United States. Survey respondents were asked about their physical activity behaviors and classified into three groups: meeting physical activity guidelines (at the time of the study, 30 minutes of moderate-intensity aerobic physical activity on five or more days per week), insufficiently physically active (some activity reported, but not meeting the guidelines), and inactive (no physical activity reported). The authors studied injury patterns occurring acutely during physical activity and in times not associated with physical activity across the three groups. Key results are shown in figure 10.2.

The risk of exercise-related musculoskeletal injury was elevated during physical activity in both groups (20% in those who were insufficiently active and 53% in those who were meeting physical activity guidelines). This was expected because more active people seem to be at higher risk for injury during physical activity. The surprising finding came in the overall injury risk (combining exercise- related and nonexercise-related injuries). People who were active (– 3%) or somewhat active (–12%) were actually at a lower overall risk of injury compared to inactive people. The finding was particularly striking for injuries not due to physical activity. These results seem to suggest that, although the risk of exercise-related musculoskeletal injuries is elevated during exercise, people who are habitually active have a lower overall risk of any injury.

Figure 10.2   Association of habitual physical activity with risk of injury during physical activity and overall. Risk of injury is relative to inactive subjects. Adapted from Carlson et al. (2006).

Many people believe that stretching muscles prevents exercise- related musculoskeletal injuries. Stretching, either before or after an exercise session, feels good and increases flexibility around the joints. The theory is that this increase in flexibility and additional blood flow to the areas being stretched put muscles, joints, and connective tissues at a lower risk of strain or stress and subsequently a lower risk of injury. Although this is an attractive hypothesis, the results of numerous studies have failed to confirm this finding. In fact, the scientific literature is now consistent with the conclusion that stretching before or after an exercise session does not decrease the risk of injury. Flexibility is obviously an important component of physical fitness but it does not seem to result in a lower risk of exercise-related musculoskeletal injuries.

SUDDEN ADVERSE CARDIAC EVENTS

The images are all too familiar: A recreational runner dies during a weekend 10K race. A homeowner shoveling snow from his driveway after a winter storm falls to the ground and dies. A young, seemingly fit and healthy basketball player dies during a game. Sudden cardiac death is an unexpected death due to a dysfunction of the heart, usually within one hour of the onset of symptoms. Physical activity and exercise, particularly when performed at a vigorous intensity, are associated with a higher risk of a sudden adverse cardiac event (i.e., cardiac arrest, cardiac death), when compared to times of no activity or light- or moderate-intensity activity.

When does the highest risk of a cardiac event associated with exercise occur?

Many types of cardiac disorders can place people at an increased risk of sudden cardiac death. As reviewed in chapter 5, the risk of atherosclerotic heart disease is substantially lower among people who are or who become physically active. This lower risk is primarily seen in men and women older than 30. Other disorders, including hypertrophic cardiomyopathy (a genetic disorder characterized by an

overly thick wall in the left ventricle), electrical conduction disorders, and abnormalities in the cardiac arteries, are all important conditions that place people at risk of sudden cardiac death, particularly during physical activity and exercise. Such conditions are mostly inherited. Although regular participation in moderate-intensity physical activity can lower the risk of chronic diseases and conditions such as obesity, atherosclerotic heart disease, diabetes, colon and breast cancer, and osteoporosis, people with conditions that increase the risk of sudden cardiac death should avoid vigorous-intensity physical activity. Moreover, people with a family history of these conditions should be examined and monitored by a physician.

Vigorous-intensity physical activity has also been shown to be a trigger for sudden cardiac death due to atherosclerotic heart disease. This process, thought to be a result of a fibrous plaque that ruptures inside a coronary artery and essentially cuts off the blood flow to a portion of the heart, can be a very dangerous situation. Evidence of this process comes from studies of people who have had sudden adverse cardiac events.

OVERLOAD, ADAPTATION, AND SPECIFICITY The fundamental principles of overload, adaptation, and specificity outlined in chapter 2 are particularly relevant when discussing the prevention of exercise- related musculoskeletal injuries. Overload, or exercising beyond usual levels, stimulates bones, muscles, joints, and connective tissue to increase their function. If this overload is sustained (or repeated frequently), the body adapts to a new normal based on the physical training. Laboratory-based studies and animal studies have taught us that bones, muscles, ligaments, and tendons all adapt to increased physical activity (i.e., they get stronger with more physical activity, or overload), and that targeted activity (e.g., focusing on the lower limbs) will likely prevent injuries in that area. However, large overloads with little or no time to adapt may increase the risk of exercise-related injury (particularly traumatic injury),

and little or no overload does not prompt any adaption, and may also increase the risk of injury.

Mittleman and colleagues (1993) studied more than 1,200 men and women who had survived a myocardial infarction (i.e., a sudden loss of oxygen to the heart muscle). They interviewed all study subjects and determined what they were doing immediately prior to or during the cardiac event and classified them based on whether they were physically active. Figure 10.3 illustrates the main results.

Figure 10.3   Relative risk of onset of myocardial infarction by hours of exertion prior to an event. Adapted from Mittleman et al. (1993).

As figure 10.3 shows, the risk of a myocardial infarction related to exertion is largely limited to the first hour after the activity. During this time, men and women in this study were nearly six times more likely to develop a myocardial infarction. After the first hour, the risk was

negligible. Although these events were nonfatal, this evidence is compelling and clearly suggests that the period of highest risk for an adverse cardiac event is during or within the first hour after cessation of exercise.

If vigorous-intensity physical activity increases the risk of adverse cardiac events, why is it recommended? Why promote physical activity if it increases the risk of death or nonfatal heart attacks? The answer to this question lies in the big picture. Multiple studies since the 1980s have shown that, although vigorous-intensity physical activity acutely increases the risk of sudden cardiac death, the overall risk of sudden cardiac death (throughout the rest of the day) is actually lower among people who are habitually physically active. That is, the cardiac risk that occurs as a result of an acute bout of physical activity is outweighed by an overall lower risk of sudden death in active people compared to inactive people. This concept is perhaps best illustrated by figure 10.4.

Figure 10.4   Risk of cardiac arrest during vigorous-intensity physical activity and at rest by usual level of physical activity. Reprinted from USDHHS, PAGAC (2008).

Over a 24-hour period, the risk of cardiac arrest for someone who remains inactive (thin unbroken line in figure 10.4) is far higher than the average risk for someone who is habitually active (dashed line). The risk for cardiac arrest is far higher for that active person during or immediately after the period of physical activity (spike), but overall, the active person is at a much lower risk (even when this

period of activity is taken into account) than the inactive (sedentary) person. This situation is similar to that reviewed earlier for musculoskeletal injuries. The overall benefit to being physically active far outweighs the short-term acute risk of adverse events due to physical activity.

LEADER PROFILE Michael Pratt, MD, MSPE, MPH

Why and how did you get into the field of Physical Activity and Public Health? By repeatedly being in the right place at the right time. I was a track and cross country runner at UC Davis and interested in the science behind running and performance. Those experiences led me to graduate school in exercise science in the Kinesiology Department at the University of Washington where, among other things, I ran rats on a treadmill and studied their mitochondria. I came to the conclusion that I needed further education, and that I preferred my study subjects alive rather than in a blender, thus I opted for an MD as opposed to a PhD in physiology. While I was in med school at the University of Washington, Ken Powell organized a seminal workshop on physical activity and public health at the Center for Disease Control (as the CDC was know as at that time). The

workshop proceedings were published in Public Health Reports (1985) and created a framework for understanding

physical activity as a public health issue. This was amazing—it was actually possible to combine the two areas I was most interested in: epidemiology and physical activity!

Did any one person have a major influence on your career? How? Upon reflection the answer here is two people. The aforementioned Ken Powell is one major influence, as I eventually found my way to the CDC to be mentored by Dr. Powell. As you might expect of somebody who defined a new field within public health, Ken is visionary, intelligent, and a master of the craft of epidemiology, but he is also humble and simply a wonderful person. Thanks to Ken, I became a physical activity and public health guy, but I was predestined to be a scientist of some sort. My father was a microbiology and genetics professor at the University of Wisconsin and UC Davis. I spent many hours as a little kid hanging out in my dad’s lab surrounded by pipettes, petri plates, postdocs, and the whole academic milieu. Discovery, collaboration, teaching—if it was the right thing for my Dad it must be what I was meant to do.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? I always describe myself as a generalist in a specialized area. This is par for the course for many physicians in public health. We need to be pretty good at a variety of things because all those PhDs are so much smarter than us in their specialty areas. So I have done some surveillance, physical activity (PA) counseling research, community interventions, environment and PA, economics, and eventually what I currently focus on, global PA policy. Translating research into practice and policy is never easy. It is facilitated by partnering from the start with communities, governments, and international organizations, such as WHO, and being very focused on a few factors that are generally undervalued in biomedical research: external validity, feasibility, pragmatism.

Why do you do what you do? The same reason as pretty much everybody in public health— to try to make the world a better place.

What are two key issues that must be addressed by 2030?

1. Equity. Physical activity is good for everyone, but the distribution of these benefits across society and

across the globe is far from uniform. From basic

research to public policy—we need to close these gaps.

2. Harnessing technology and data science for physical activity surveillance. We have done pretty well using

self-report to guide our work on physical activity and

health, but the tools now exist to be much more

precise. However, there are important and exciting

challenges around conceptual differences between self-

report and objective measures, sampling, continuous

data collection, data synthesis, scoring, and

interpretation of this information to enhance our

understanding of basic health relationships and guide

policy.

Must someone who is sedentary consult a physician or other health care provider prior to beginning a physical activity program? This message has been around for many years and always seems like a good idea. The reality, however, is that this creates a significant barrier for many people who can use it as an excuse not to exercise.

According to the 2008 U.S. Physical Activity Guidelines Advisory Committee (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2008), there is no evidence that people who visit a physician or other health care provider prior to starting an exercise program are any safer than those who do not. Following the fundamental principles of exercise physiology (overload, adaptation, and specificity) by making small, comfortable increases in physical activity over one’s usual behavior should minimize any acute cardiac or musculoskeletal risks associated with physical activity. In these

cases, consultation with a health care provider is not necessary. People who plan to make large, high-intensity increases in physical activity without allowing for any adaptation time, who have chronic conditions that may increase acute risk, or who have general concerns about exercising should consult with a health care provider. Someone who is sedentary and wants to begin exercising with a walking program of light to moderate intensity would not need such a consultation.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Musculoskeletal injuries and sudden adverse cardiac events are two important risks of physical activity participation. The exercise physiology principles of overload, adaptation, and specificity are important considerations in understanding the risks of exercise and physical activity. The definition of musculoskeletal injury is an important consideration for interpreting the literature. Studies of musculoskeletal injury prevalence and incidence must take the population at risk into account. The acute risks of injury and adverse cardiac events are elevated during or immediately after a physical activity bout. The overall risk of both conditions is lower among people who are habitually physically active. Consultation with a medical care provider may be necessary for some people, but for the majority of sedentary people who wish to become active at a moderate level, such requirements should not be a barrier to participation. The benefits of physical activity participation far outweigh the risks.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Almeida SA, Williams KM, Shaffer RA, Brodine SK. 1999.

Epidemiological patterns of musculoskeletal injuries and physical training. Medicine & Science in Sports & Exercise 31: 1176-1182.

Carlson SM, Hootman JM, Powell KE, Macera CA, Heath GW, Gilchrist J, Kimsey CD Jr, Kohl HW III. 2006. Self-reported injury and physical activity levels: United States 2000-2002. Annals of Epidemiology 16: 712-719.

Gotsch K, Annest JL, Holmgren P, Gilchrist J. 2002. Nonfatal sports- and recreation-related injuries treated in emergency departments—United States, July 2000–June 2001. Morbidity and Mortality Weekly Report 51: 736-740.

Hootman JM, Macera CA, Ainsworth BE, Martin M, Addy CL, Blair SN. 2001. Association among physical activity level, cardiorespiratory fitness and risk of musculoskeletal injury. American Journal of Epidemiology 154: 251-258.

Macera CA, Pate RR, Powell KE, Jackson KL, Kendrick JS, Craven TE. 1989. Predicting lower-extremity injuries among habitual runners. Archives of Internal Medicine 149: 2565-2568.

Mittleman MA, Maclure M, Tofler GH, Sherwood JB, Goldberg RJ, Muller JE. 1993. Triggering of acute myocardial infarction by heavy physical exertion: Protection against triggering by regular exertion. New England Journal of Medicine 329: 1677-1683.

Mueller FO, Cantu RC. 1991. The annual survey of catastrophic football injuries: 1977-1988. Exercise and Sport Sciences Reviews 12: 261-312.

Powell KE, Heath GW, Kresnow MJ, Sacks JJ, Branche CM. 1998. Injury rates from walking, gardening, weightlifting, outdoor bicycling and aerobics. Medicine & Science in Sports & Exercise 30: 1246-1249.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

2.1.1, 2.2.1, 2.2.2, 5.2.5, 6.1.1, 6.1.3, 6.1.4, 6.1.5, 6.2.1, 6.3.1, 6.3.6, 6.4.1, 6.4.4

PART III Strategies for Effective Physical Activity Promotion

CHAPTER 11 Informational Approaches for Promoting Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The Guide to Community Preventive Services Task Force recommendations for physical activity promotion

»  The rationale for promoting physical activity interventions through informational approaches

»  Considerations for using community-wide campaigns

»  Considerations for using mass media campaigns »  Characteristics of effective health education curricula »  Considerations for using classroom-based health

education programs

OPENING QUESTIONS »  Have you ever tried to help someone increase physical

activity levels or begin an exercise program by providing information on the health benefits of physical activity?

»  Did it work? How successful were you over the short term and long term?

»  Which types of informational approaches actually increase physical activity?

»  What are the components of these approaches?

Parts I and II of this text focused on defining the field of physical activity and public health and on outlining the myriad health benefits to being physically active. In this part of the text we introduce strategies that have been proven to help people increase or maintain their physical activity levels. The information in this part, derived from behavioral, population, and environmental research, separates public health research from other forms of research. In most cases, results from public health research are translated into practice to improve the health of populations and individuals. Public health research generates new knowledge, as do virtually all other types of research. Fundamentally, though, applying the results of public health research to a particular health problem is a critical step.

The best resource for translating public health research into practice in the United States is The Guide to Community Preventive Services, or the Community Guide. The Community Guide contains guidance on health improvement strategies for numerous topics, including physical activity. Each recommended strategy in the

Community Guide is based on a rigorous review of available scientific evidence—the recommended strategies for health promotion and disease prevention that are found in the Community Guide, for example, have been thoroughly reviewed and scientifically tested.

The Physical Activity sections of the Community Guide include the following review areas, which are discussed here and in more detail in chapters 12 through 14:

School-based methods (chapter 12) Behavioral and social methods (chapter 13) Environmental and policy approaches (chapter 14)

UNDERSTANDING THE COMMUNITY GUIDE The Community Guide is an ever-expanding resource for recommendations on evidence-based interventions to improve public health. The Task Force on Community Preventive Services (Task Force) was established by the U.S. Department of Health and Human Services (USDHHS) in 1996 to clarify which community- based health promotion and disease prevention interventions work, and which do not. The U.S. Centers for Disease Control and Prevention (CDC) is the USDHHS agency that provides the Task Force with technical and administrative support. Our review is drawn from the recommendations in the Community Guide, but we recommend that you also visit the Community Guide website and read the information contained there as well (www.thecommunityguide.org).

The information in the Community Guide provides support for a variety of activities related to public health, such as the following:

Policies. Provides an understanding of concepts and research that can help in the development of more effective legislation and organizational policies.

Research. Identifies research gaps, research priorities, and high-quality evidence-based studies. Programs. Helps with program planning and health promotion services. Education. Disseminates knowledge of effective public health strategies. Funding. Provides background information for creating grant proposals and gaining access to funding streams. General. Helps determine what works and how to make wise use of resources, and builds community support.

EVIDENCE-BASED PUBLIC HEALTH The Community Guide offers practitioners and decision makers strategies for preventing or addressing health problems. To save from having to continually try various strategies that may or may not be successful, the Community Guide provides a one-stop shop for people interested in translating research into programs that have a better chance of succeeding. The Community Guide saves time and money and helps keep public health program developers from having to reinvent the wheel. When in doubt, go with the evidence-based strategy.

When reviewing research from physical activity programs, the Task Force takes into account the types of activities targeted, the breadth of their impact, how programs are delivered, the target population, and the type of setting in which the programs are delivered. The Task Force also seeks the answers to the following questions about specific physical activity interventions:

Does it work? If it does work, how well? For whom does it work?

Under what circumstances is it appropriate? What does it cost? Does it provide value? Are there barriers to use? Are there any risks? Are there any unanticipated outcomes?

Reprinted from the Community Guide.

Although a review of all the criteria the Community Guide uses to judge a study or studies is beyond the scope of this text, suffice it to say that they are very stringent. Only the best studies, with adequate numbers of participants and methods, are evaluated. Once all of the studies in a particular area are assessed, the Task Force recommendations about specific physical activity programs are categorized into the following three broad groupings:

Recommended: Strong or sufficient evidence that the intervention or program is effective. Recommended against: Strong or sufficient evidence that the intervention or program is not effective, or is harmful. Insufficient evidence: The available studies do not provide sufficient evidence to determine whether the intervention is effective.

Classifying a program as having insufficient evidence can mean one of several possible things. First, additional research may be needed to determine whether the intervention is effective; the number of studies may be insufficient to draw any firm conclusions; or the studies may lack sufficient quality. Second, the studies may all be of sufficient quality and size, but they may present inconsistent or contradictory findings, or both. Finally, the studies may be consistent, but the results may not be of sufficient size or intensity to confidently describe an effect—that is, the statistical significance of the findings

may not support the results. In this case insufficient evidence does not mean that the intervention or program does not work.

RATIONALE FOR INFORMATIONAL APPROACHES If knowledge is power, does more knowledge about the health benefits of physical activity translate into more power to change behavior among people who are physically inactive? Informational approaches may be designed to increase leisure, occupation, transportation, or at-home physical activities. These approaches are based on the idea that when people are taught about the health benefits of a certain behavior (such as physical activity), they will change their behavior for the better. Obviously, we all know that we sometimes choose to behave in ways that are not good for us; however, informational approaches can increase our knowledge and reinforce our desire to change when we are motivated to make a change.

In general, informational approaches to physical activity promotion may change behaviors through several pathways. First, an increase in knowledge about the health benefits and risks of physical activity (see chapters 5 through 10) may be sufficient for behavior change in some people. For example, a person with a substantial family history of heart disease may be more likely to become physically active if she learns that activity may lower her risk due to her genetic makeup.

Second, informational approaches may encourage people to be physically active by extending their knowledge about where and how to be active in their communities. For example, building a bicycle trail may not be enough to encourage physical activity; however, providing information about the trail, its entry and exit points, safety features, and other characteristics may increase the use of the trail for physical activity.

Third, informational strategies may help people identify the personal and environmental reasons they are physically inactive and help them overcome them. Finally, informational approaches can let

people know when opportunities for physical activity are happening in their communities, at their worksites, or in other settings. This knowledge can then be converted to action. For example, when a neighborhood walk or other event is scheduled, informational approaches can increase awareness, registration, and participation in the event, thereby increasing physical activity.

TIME Time—no one has enough of it; everyone is busy. Lack of time is consistently cited in surveys and studies as the number one reason people are not physically active. Although it may be true that people make time for things that are important to them, informational approaches to physical activity participation can help people identify why they believe they don’t have time to be physically active and how they can rearrange their schedules to make room for physical activity.

Informational approaches for promoting physical activity that have been evaluated by the Task Force include community-wide campaigns, mass media campaigns, and classroom-based health education curricula for youth that focus on providing information and skills development. The remainder of this chapter reviews each of these informational approaches, provides an assessment of the effectiveness of each in promoting physical activity, and provides examples of success.

COMMUNITY-WIDE CAMPAIGNS Have you ever seen a billboard in your community that urges you to exercise more, or a late-night television advertisement or intranet site at your workplace or university that reminds you to be physically active? Have you ever received an email reminding you of the health benefits and importance of being physically active? These are all examples of informational approaches to promoting physical activity.

Unfortunately, these “single-stream” techniques rarely, if ever, succeed in getting people to become more active.

When single-stream techniques are combined into multiple intensive strategies targeted toward increasing physical activity, however, they can be successful. One of the recommended strategies for increasing physical activity via informational approaches is a community-wide campaign. These campaigns rely heavily on communication to change behavior through increased knowledge.

Community-wide informational campaigns for physical activity promotion have three defining characteristics. First, they include many community sectors. That is, they are not limited to messages from the local health department, parks and recreation department, hospital, or mayor’s office. Successful programs create consistent messages and program identification (e.g., logos, tag lines) across those sectors.

Second, community-wide informational campaigns frequently include very visible, broadly targeted strategies. To succeed, they cannot be limited to one-way communication methods, such as television advertisements or billboards by the side of the road. Rather, they should be incorporated into other health-related events, such as health fairs, cancer screening events, and other activities where people may gather. Moreover, social media strategies (mobile and desktop) can supplement one-way communication strategies and make them interactive.

Finally, community-wide informational campaigns can be successful if they are included in other activities that focus on physical activity–related health issues. For example, a heart disease prevention program at a large worksite may include physical activity promotion information. Such programs have been shown to increase physical activity in the targeted population.

Community-wide informational campaigns often include television, radio, newspaper, and other media to raise program awareness, disseminate physical activity health messages, and reinforce

behavior change. Targeted mailings and communications from key influencers such as places of worship and community centers that support the informational campaign can also be very effective.

Community-wide campaigns, if done correctly, have been shown to be effective strategies to promote physical activity. Let’s Move! is former First Lady Michelle Obama’s initiative to reduce childhood obesity. Reprinted from Let’s Move Outside: America’s move to Raise a healthier Generation of Kids.

Taken together, existing studies in this area show that community- wide informational campaigns to increase physical activity do the following:

Increase the percentage of people who report being physically active (at least in the short term) by an average of 4.2%. Increase caloric expenditure by an average of 16.3%. Increase multiple types of physical activity. Increase participants’ knowledge about exercise and physical activity. Increase participants’ intentions to be physically active (even though they may not actually be carrying through on those intentions).

Reduce risk factors for cardiovascular disease that are related to physical inactivity.

Of note, however, is that these same studies reported equivocal findings on body weight. Some studies showed weight loss, but others showed no change or even slight weight gains. Thus, it is clearly possible to increase physical activity without weight loss.

Community-wide campaigns for physical activity promotion are typically not easy to organize. They require substantial planning, coordination, and evaluation efforts to determine effectiveness. Partnerships must be developed, and partners need to be counted on to assist in the campaign. An underfunded and underplanned campaign will underperform.

MASS MEDIA CAMPAIGNS Mass media campaigns are physical activity promotion programs that rely on messaging efforts to change physical activity behavior through changes in knowledge, beliefs, and attitudes. The exposure to mass media campaigns can be measured in a variety of ways, but is usually summarized as the number of times an average target group member will view, hear, or see the message. Such campaigns can (and probably should) be part of a community-wide informational campaign, but do not constitute a community-wide effort on their own. Following are characteristics of mass media campaigns for physical activity promotion:

Are typically designed as large-scale efforts to transmit messages about physical activity to large and nonspecific audiences; anyone is considered a target. Are designed to increase physical activity by increasing knowledge and changing attitudes and beliefs. Use communication media exclusively, including newspapers, TV, radio, and billboards. Can rely on a single communications channel (e.g., billboards) or a combination of channels.

The Task Force found insufficient evidence to recommend mass media strategies for physical activity promotion. These kinds of programs can be very expensive and difficult to carry out, and the money spent may well be wasted. Many reasons may explain this lack of effect, including poorly produced or poorly placed media products and the lack of a defined target audience.

Although the Community Guide does not recommend mass media approaches for physical activity promotion because of insufficient evidence, research evidence has emerged that has led some authors to label the strategy as promising (Heath 2009).

Why don’t mass media campaigns seem to work for physical activity promotion? Many communities and countries have used such campaigns, yet changes in behavior across a target audience have been difficult to demonstrate. Bauman and Chau (2009) reviewed mass media campaigns and provided some ideas about why they were not successful. First, the campaigns may not have had consistent, comprehensive messaging strategies. For example, some campaigns focused on increasing exercise behaviors, whereas others focused more broadly on physical activity of all kinds. Alternatively, some focused on sport participation, whereas others focused on lifestyle-related physical activity.

Second, the target behavior was inconsistent. Urging people to take a walk is not the same as urging them to meet the recommendation of 150 minutes per week of moderate-intensity physical activity. Mass media approaches may work for one type of activity outcome, but not for another.

Third, the campaign may not have been sequenced correctly. Sequencing here means that the messages are built on one another in a logical fashion to encourage behavior change.

Fourth, resources may have been insufficient to reach deeply into the targeted audience or to evaluate the effectiveness of the campaign properly. As with community-wide campaigns, underfunded efforts are likely to underperform.

Finally, to have a reasonable chance at success, mass media campaigns for physical activity promotion cannot be used in isolation (Bauman and Chau 2009). They must be implemented as part of comprehensive programming with messaging supporting the policies, programs, and environment of the specific physical activity intervention. In other words, mass media campaigns that are implemented without supporting actions, policies, or places for activity are not effective.

Clearly, television, radio, and print media are giving way to electronic, web-based, and social media. Can these new media be useful in promoting physical activity, and should they be considered mass media strategies? The question is a bit tricky because electronic media allow messages to be tailored to (and by) the people being targeted, rather than a more traditional one-size-fits-all approach that has characterized mass media strategies to date. Campaign developers can tailor the type, frequency, and appearance of the message to the characteristics of the receiver. This is very different from the “blunt instrument” approach of traditional mass media. Bauman and Chau (2009) evaluated new media physical activity interventions (primarily web-based) and concluded that these new methods of social marketing can be developed and tailored to individuals to encourage behavioral change, but more research is clearly needed in this area.

CASE STUDY

ACTIVE AUSTRALIA Can the physical activity levels of an entire state be improved? Active Australia (Bauman et al. 2001) is a perfect example of a community-wide campaign that was

able to show that they could. In a two-month period in 1998, a statewide campaign was initiated and conducted by the New South Wales (Australia) state health department. The campaign sought to increase physical activity levels in adults 25 to 60 years of age. Informational strategies used in the project included paid television and print advertising, marketing of campaign merchandise (branded with logos), multilingual outreach, and mailings to public health professionals and medical personnel throughout the state. Mass participation events such as community walks were scheduled in towns throughout the state to reinforce the objectives of the campaign.

At the completion of the two-month program, its effects were evaluated. A random sample of residents in New South Wales was identified for data collection before and after the program, as was a random sample of residents of outlying states who did not receive any of the materials (a control group).

The main findings from the evaluation of this program are shown in figure 11.1. Residents of New South Wales reported higher physical activity participation levels at the end of the campaign, whereas people not exposed to the campaign actually showed a statistically significant decline in hours per week of physical activity. Other markers of physical activity participation showed similar findings. Moreover, the campaign was quite successful in the target group in increasing awareness (recognition of the campaign) and knowledge of aspects related to physical activity (e.g., how much, how often), as well as self-efficacy to become more physically active. Although these are short-term findings (whether the gains remained past the time period of interest is unknown), they quite powerfully show that a community-based informational campaign can in fact increase the physical activity behaviors of an entire state.

Figure 11.1   Changes in physical activity participation using a community-wide informational campaign: Active Australia. Adapted from Bauman et al. (2001).

Although web-based and electronic physical activity promotion programs show promise for increasing physical activity levels, the current evidence is inconclusive. The costs of web-based physical activity interventions are relatively low, but studies and research about their effectiveness need to be more focused on measurable outcomes as access to and the availability of web-based campaigns continue to evolve. Combinations of traditional and emerging mass media campaigns (e.g., face-to-face with electronic follow-up) are

just beginning to become more readily available technologically. Examples of web-based media interventions that have had at least some success include several YouTube sites. These are found in the e-Media materials at the end of this chapter, which you should find fun to explore and discuss with your colleagues.

CASE STUDY

VERB The VERB campaign was the first U.S. national mass media campaign to promote physical activity. The campaign was developed and implemented by the U.S. Centers for Disease Control and Prevention (CDC) in 2002 (Huhman et al. 2005). The purpose of the campaign was to increase and maintain physical activity among tweens (youth ages 9 to 13) throughout the United States. Paid television advertising was used on channels frequented by the target audience. Additionally, the program included radio advertising, websites, and other communications links all designed to make physical activity an attractive, “cool” behavior.

After one year, although the campaign seemed to have no overall effect on physical activity levels, several population subgroups did show increases in physical activity sessions per week. Girls, younger children, initially inactive children, and other subgroups reported becoming more active. The campaign did reach a majority of its intended audience, and most children and their parents recognized the campaign logo and materials and understood what it was about; you or an older sibling may have been part of the VERB campaign! Although not definitive, the results from VERB are promising in that a large-scale paid media campaign seemed to change physical activity behaviors in some

population groups. Clearly, more research is needed in this area.

CLASSROOM-BASED HEALTH EDUCATION PROGRAMS Although many definitions exist, health education can be roughly defined as the processes through which people learn about personal health concepts and behaviors. Health education curricula have become an important part of instructional goals for elementary, middle, and high schools. Classroom-based health education programs are usually focused on providing information to help students make rational decisions about adopting healthy behaviors. Ideally, these curricula avoid an overreliance on teaching facts alone. Rather, the more effective health education curricula provide essential information and concepts and then help to shape values and norms that will result in positive health behaviors.

Clearly, variability in the quality of health education curricula is to be expected. Some may not be funded adequately, some may not address issues important to the children, and in some cases the instructor may not be a helpful role model (e.g., teaching children about not smoking while being a smoker!). The Centers for Disease Control and Prevention proposed a series of criteria that, taken together, define an effective health education curriculum. These are summarized in the highlight box Characteristics of Effective Health Education Curricula.

How do informational approaches, such as a community campaign to raise awareness of a new playground, help promote physical activity and exercise?

Can information transmitted in classroom-based health education programs increase physical activity? Because so many students are exposed to such curricula, the potential for reaching a broad audience is great. Health education curricula can also supplement physical education curricula and classes. Ideally, such curricula would result in changes in self-reported or objectively measured physical activity (usually away from school), changes in BMI or adiposity, changes in physical fitness (e.g., aerobic capacity,

strength), improvements in general health knowledge related to physical activity, and possibly improvements in self-confidence and self-efficacy to be physically active. Some characteristics of classroom health education programs attempting to increase physical activity are as follows:

Provide knowledge and skills for healthy decision making. Work at the individual level (personal and behavioral). Usually include several components (e.g., tobacco use, nutrition, physical activity) and focus on reducing the risk of chronic disease. Teach behavioral skills, but have no added (in-class) physical activity component.

CHARACTERISTICS OF EFFECTIVE HEALTH EDUCATION CURRICULA

Have clearly defined health goals, with behaviors

that are linked to those goals.

Are based on research, but rooted in theory.

Define and describe age-appropriate peer and social

norms for health behaviors, and anchor health values

and beliefs.

Help students understand their own personal risks for

certain health behaviors.

Teach skills for dealing with social pressures to

engage in bad health behaviors.

Teach skills that result in self-confidence and

competence to engage in desired health behaviors.

Provide age-appropriate and culturally appropriate

learning strategies, materials, and examples.

Provide adequate time for instruction, reinforcement

of lessons, and skill and behavioral practice.

Provide opportunities to connect with appropriate

role models such as peers, family members, and

community leaders.

Include support for teachers to enhance their

teaching effectiveness.

Adapted from CDC 2011.

CASE STUDY

COLLEGE-BASED HEALTH EDUCATION What happens to physical activity levels in late adolescence and early adulthood? Numerous researchers have reported that it declines significantly, which results in continued inactivity in most adults. Dr. James F. Sallis and colleagues (1999) designed Project GRAD (Graduate Ready for Activity Daily) to study the effectiveness of a college health education class in increasing physical activity levels. In the study, 338 students ages 18 to 29 years were randomly assigned, after baseline measurements, to intervention or control groups. Posttest data were reported for 321 students after one semester, and one and two years after baseline. The test group of students took a semester- long course that promoted the adoption and maintenance of physical activity. The lessons each week were rooted in behavioral science theory designed to support behavior change. The control students took a semester- long course on a variety of health education topics.

The GRAD intervention integrated concepts from exercise science and behavioral science based on national physical activity recommendations at the time of the study, social cognitive theory, and behavioral

change theory. The intervention course included a 50 minute once per week lecture about physical activity and behavioral topics, and a weekly 110-minute lab that included 15 minutes of physical activity (no equipment), 25 minutes of behavior group discussion, and another 45 minutes of varied physical activity with equipment as required. Primary measures included assessments of behavioral change stage and 7-day Physical Activity Recall interviews.

The main results of Project GRAD showed no significant effects on men during the semester-long intervention. Men were more active than women at baseline, at least in the maintenance stage for physical activity, which may have made increases difficult to achieve. The women in the intervention showed significant increases in physical activity levels during leisure, strengthening, and flexibility exercises.

Although the reasons for the lack of consistent results are unclear, the authors hypothesized that the participants may not have been far enough along in terms of their readiness to begin physical activity. As a result of this study, the authors recommended that starting earlier (than college) may be a better approach. Interestingly, in a follow-up study of Project GRAD, Calfas and colleagues (2000) reported no significant effects on physical activity outcomes for men or women after two years, despite excellent participation in the theoretically based intervention. College-based health education seems to improve knowledge, but not behavior.

Unfortunately, the available scientific evidence does not support the use of classroom health education as a method to increase physical activity behaviors. The Community Guide has concluded that there is insufficient evidence to determine the effectiveness of classroom-based health education programs. The primary findings showed little evidence of increased student physical activity levels. As with mass media and other informational strategies, health education does seem to increase general health knowledge,

knowledge related to physical activity, and even self-efficacy about exercise. Unfortunately, these increases do not translate into behavior changes.

LEADER PROFILE Ulf Ekelund, PhD

Why and how did you get into the field of Physical Activity and Public Health? I think my background might be slightly different from many other academics. When I was growing up, I loved sport and exercise and wanted to become a physical education teacher. I was trained in physical education and biology at the University in Örebro, Sweden, and then worked as a teacher for almost seven years until I was recruited to teach exercise science at my alma mater. I soon realized I needed a PhD to obtain a permanent position at the University. I had the opportunity to enroll in the graduate program at the Karolinska Institute and conducted my PhD on assessment of energy expenditure and physical activity in adolescents. In the late 1990s the development of device-based methods for assessing physical activity, such as heart rate monitoring and accelerometry, became available for population-based research and I used these methods in my dissertation. While working on my PhD I was fortunate to be involved in the European Youth Heart Study and the development of the International Physical Activity Questionnaire (IPAQ) and some other projects, which were

amazing opportunities to get to know some of the major players in this field. I was fortunate that when I finished my PhD I was offered the opportunity to work at the Medical Research Council Epidemiological Unit at the University of Cambridge. What I assumed was going to be a one year postdoc experience ended up being almost 10 years long. Working in an extraordinary research environment at one of the most prestigious universities in the world was extremely challenging. My research shifted from being focused on the assessment of physical activity into a more broad epidemiological approach to understanding the role of sedentary time and physical activity for preventing noncommunicable diseases across the lifespan, and how to translate these findings into public health action.

Did any one person have a major influence on your career? How? There are a number of people who influenced my career. When studying physical education and exercise science in Sweden during the ’90s I was obviously influenced by the work of Per-Olof Åstrand and Bengt Saltin. During my undergraduate training I took a course in preventive medicine with Björn Ekblom who really sparked my interest for research and the importance of physical activity for health. During my initial year as a PhD student, I was fortunate to meet with Chris Riddoch from Bristol at my first scientific conference ever (OK, we actually met in a pub during the conference) which led to my involvment in the European Youth Heart Study (never underestimate a pub visit). However, the most influential academic, who also recruited me to Cambridge and allowed me to develop my own research program in physical activity epidemiology is Nick Wareham. Last but certainly not least, I should also mention my family who always support me and hardly ever complain about me working abroad, first in Cambridge and now in Oslo.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My research has gradually shifted from being focused on the assessment of physical activity into an epidemiological approach to understanding the role of sedentary behaviors and physical activity for preventing

noncommunicable diseases across the lifespan, and how to translate these findings into public health action. I also have a strong interest in population levels and trends of physical activity and how to promote physical activity in everyday life.

Why do you do what you do? Physical activity is one of the most important behaviors for health, and I strongly believe that research is needed to inform public health action. Working with great colleagues and students in an extraordinary environment at the Norwegian School of Sport Sciences makes everyday in the office enjoyable.

What are two key issues that must be addressed by 2030? Along with global warming and reducing carbon dioxide emissions—issues that I truly believe need substantial societal changes, including adjustments in how we live our lives—the global pandemic of physical inactivity needs to be reversed. I believe these two issues are interlinked in terms of public transportation, environmental planning, and clean air.

One of the striking observations from the preceding list of characteristics of classroom-based health education programs for physical activity promotion is that very few, if any, of the programs focused solely on physical activity. Usually, the programs included physical activity information and education as part of a larger curriculum on reducing the risk factors of chronic disease. Moreover, although many programs focused on developing skills for being physically active, they did not provide students with time to actually be physically active! Ideally, such a curriculum would focus solely on physical activity skills and building knowledge around the characteristics of effective health education curricula outlined earlier. It is likely that the lack of evidence of program efficacy is because programs have not gone far enough to have a reasonable chance of success.

In summary, informational approaches to physical activity promotion seem to increase knowledge, change attitudes, and even

improve self-efficacy about physical activity (i.e., the belief that one can actually be more physically active). However, concurrent changes in behavior (what we are interested in) are elusive. The only strategy likely to show (short-term) increases in physical activity behavior is community-wide campaigns. More work is needed in this area to better understand it. Can you think of a research question that could help?

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

The Community Guide is an ever-expanding resource of recommendations on evidence-based interventions to improve public health. The Task Force categorizes recommendations about specific physical activity interventions as recommended, recommended against, or having insufficient evidence. Informational approaches may be designed to increase leisure, occupation, transportation, or at-home physical activities. Community-wide campaigns are recommended for physical activity promotion and should include strategies to promote increased awareness and knowledge, enhance motivation and readiness to change behaviors, and teach or enhance the skills needed to establish and maintain desired behaviors. Mass media campaigns can be large-scale efforts that address messages about physical activity to large and undifferentiated audiences. Mass media campaigns seem to improve awareness and knowledge but alone should not be expected to increase physical activity.

New media and web-based physical activity interventions show promise for increasing physical activity levels, but the current evidence is inconclusive. The costs of web-based physical activity interventions are relatively low, but studies and research about their effectiveness need to be more focused on measurable outcomes as access to and the availability of web-based campaigns continue to evolve. Classroom-based health education programs are usually focused on providing information to help students adopt healthier behaviors. Classroom-based health education programs do not seem to promote physical activity behaviors, although they seem to increase general health knowledge, exercise-related knowledge, and exercise self-efficacy.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Bauman A, Bellew B, Owen N, Vita P. 2001. Impact of an

Australian mass media campaign targeting physical activity in 1998. American Journal of Preventive Medicine 21: 41-47.

Bauman A, Chau J. 2009. The role of the media in promoting physical activity. Journal of Physical Activity Health 6 (Suppl 2): S196-S210.

Calfas KJ, Sallis JF, Nichols JF, Sarkin JA, Johnson MF, et al. 2000. Project GRAD: Two-year outcomes of a randomized

controlled physical activity intervention among young adults. American Journal of Preventive Medicine 18: 28-37.

Centers for Disease Control and Prevention. 2011. Characteristics of an Effective Health Education Curriculum. www.cdc.gov/healthyyouth/SHER/characteristics/index.htm. Accessed 23 July 2011.

Heath G. 2009. The role of the public health sector in promoting physical activity: National, state, and local applications. Journal of Physical Activity Health 6 (Suppl 2): S159-S167.

Huhman M, Potter LD, Wong FL, Banspach SW, Duke JC, Heitzler CD. 2005. Effects of a mass media campaign to increase physical activity among children: Year-1 results of the VERB campaign. Pediatrics 116: 277-284.

Kahn EB, Ramsey LT, Brownson RG, Heath GW, Howze EH, Powell KE, Stone EJ, Rajab MW, Corso P, Task Force on Community Preventive Services. 2002. The effectiveness of interventions to increase physical activity. American Journal of Preventive Medicine 22: 73-107.

Sallis JF, Calfas KJ, Nichols JF, Sarkin JA, Johnson MF, et al. 1999. Evaluation of a university course to promote physical activity: Project GRAD. Research Quarterly for Exercise and Sport 70: 1-10.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Division of Nutrition and Physical Activity. Brown DR, Heath GW, Martin SL, eds. 2010. Promoting Physical Activity: A Guide for Community Action, 2nd ed. Champaign, IL: Human Kinetics.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.1, 1.1.5, 1.3.1, 1.3.2, 1.3.3, 1.4.1, 1.4.2, 2.1.1, 2.1.3, 2.2.1, 2.2.2, 2.3.2, 2.3.3, 2.5.2, 3.1.1, 3.1.2, 3.2.1, 3.3.3, 3.7.1, 4.1.1, 4.1.2, 4.1.4

CHAPTER 12 School-Based Approaches to Promoting Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The rationale for school-based programming to increase physical activity

»  The current U.S. policies and strategies for school physical activity programs along with the components of effective school-based interventions

»  The current status of physical activity levels for children and adolescents globally

»  The potential physical activity and exercise outcomes for youth

»  The evidence and guidelines for physical activity and exercise for youth

»  Examples of school-based programs that increase physical activity

OPENING QUESTIONS »  Can and should schools implement physical activity programs? »  What are the components of an effective school physical

activity program?

»  What are some successful models of school-based physical activity programs?

School-based physical activity programming, such as physical education (PE) and sport participation (athletics), have been part of school culture for over 100 years in the United States and many other countries. Physical educators and coaches promote exercise to youth and young adults in schools to help them achieve or improve their physical fitness and athletic performance. Since 2005, the national focus for PE and athletics in U.S. schools has shifted somewhat to promoting physical activity for all students (more so in PE) and promoting student health and safety (more so in athletics). Schools today are also looking to promote physical activity at all grade levels in school venues other than just PE and athletics. Enhanced school-based PE is a recommended strategy that works to increase physical activity (Kahn et al. 2002, IOM 2013).

In addition to PE, schools are increasingly looking to integrate physical activity into other parts of students’ lives. Current best

practices include prekindergarten (pre-K) programs, kindergarten programs, before-school programs, classroom activity breaks, recess breaks, after-school programs, commercially sponsored programs, active transport, and summer (seasonal) programs.

RATIONALE FOR SCHOOL-BASED PHYSICAL ACTIVITY PROGRAMS This chapter is based on several detailed reports (IOM 2013; Kahn et al. 2002; Massengale 1987; Murray et al. 2019; Siedentop 2009) and the Guide to Community Preventive Services (Community Guide 2019), which support the promotion of physical activity via the education sector.

In the United States, schools have been involved in the public health and safety of children and adolescents since colonial times. Initially, schools helped combat infectious diseases; today they are being asked to lead the way in preventing and controlling the incidence of obesity, overweight, and diabetes (see chapters 5 and 6 for more). In the United States it has been estimated that over 56.6 million children and adolescents attend public and private elementary and secondary schools, where they spend approximately 6.5 hours per day for an average of 180 days per year. Additionally, over 1.4 million children attend pre-K schools, and over 12.2 million older adolescents and young adults (<25 years) attend community colleges or universities.

Because of the number of students they serve, schools at all levels are attractive public venues that can disseminate positive physical activity messages and promote active lifestyles. Mandating increased physical activity in schools has also become popular recently, because policy makers believe that it can improve adherence to varied curricular-based education to combat youth obesity, overweight, and diabetes, versus relying on students’ voluntary compliance to lifestyle change.

National legislation in the United States, including the 2004 Child Nutrition and WIC Reauthorization Act (Lee et al. 2006), ties school

funding to items such as school wellness policies that include promoting healthy eating and physical activity. National goals such as those contained in Healthy People 2010 and Healthy People 2020 (HP2020) also encourage curricular goals in school PE that include having students work at vigorous or moderate intensities for at least 50% of class time. The National Physical Activity Plan (NPAP) contains specific strategies and tactics to promote Comprehensive School Physical Activity Programs (CDC) and high quality PE programming.

HEALTHY PEOPLE 2020 Healthy People 2020, the most recent version of the health goals that are updated every 10 years by the U.S. Department of Health and Human Services, highlights disparities and opportunities for health improvement by setting public health targets to achieve in a 10-year period. Several objectives promote increased physical activity levels that are, or could be, school related. Following are some of the physical activity–related HP2020 objectives that target children and adolescents:

Increase the proportion of adolescents who meet

current federal guidelines for aerobic physical

activity and for muscle-strengthening activity.

Increase the proportion of the nation’s public and

private schools that require daily PE for all

students.

Increase the proportion of adolescents who

participate in daily school PE.

Increase regularly scheduled elementary school

recess.

Increase the proportion of school districts that

require or recommend elementary school recess for an

appropriate period of time.

Increase the number of states that require licensed

child care programs to provide physical activity.

Increase the proportion of the nation’s public and

private schools that provide access to their physical

activity spaces and facilities for all people outside

of normal school hours (i.e., before and after the

school day, on weekends, and during summer and other

vacations).

Although PE curricula have become the main focus for increasing physical activity in schools, youth cannot realistically meet physical activity guidelines (60 minutes per day; see the section on scientific evidence later in the chapter) by being active only in PE class. Even the very best physical education classes can offer on average only 20 to 30 minutes of physical activity time. Youth should be encouraged to acquire physical activity before, during, and after school in a variety of other ways, such as active transportation, play, sports, and leisure or recreation (IOM 2013). A whole-school approach is recommended by the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine, as diagrammed in figure 12.1. The model shown represents approximately 11 hours each day in which physical activity opportunities for children and adolescents might be incorporated, and provides many options for achieving the national recommendations of 60 minutes per day.

Does physical activity make children and adolescents smarter? Emerging evidence on brain function outcomes in relation to participation in physical activity and exercise indicates that there are many positive associations (see chapter 9 and figure 9.2 for more). Importantly, participation in physical activities like those described in the whole-school approach have not been shown to negatively affect academic performance.

Additionally, it is also important to note that professional organizations like SHAPE America (Society of Health and Physical Educators) provide recommended PE guidelines for children and adolescents in schools. The guidelines address teaching structures and administrative issues that can further promote physical activity participation in schools.

Schools are a major source of potential influence on children and adolescents to adopt active lifestyles. Other sectors in society such as government agencies, families, and the media can likewise influence the adoption of behaviors that can help children and adolescents achieve caloric balance (Pate and Dowda 2019). Until recently, schools were built in neighborhoods, which often positively affected the whole community in relationship to physical activity, because they were within walking distance for most students and included places at which youth and adults could be active (e.g., open green spaces, outdoor tracks, indoor and outdoor basketball courts, gyms). Schools have also traditionally offered opportunities for physical activity through PE classes, recess, and organized sports. However, with the new accountability requirements such as those of the No Child Left Behind legislation (2001), which encourage schools to focus on academic subjects such as mathematics and reading, physical education and recess time continue to be squeezed out.

Figure 12.1   The whole-school approach is designed to promote schools as a hub encouraging physical activity for children and adolescents for 60 minutes each time they visit campus. Adapted from Institute of Medicine (2013).

Adding to these challenges, most new schools are being built on the outskirts of cities as a result of urban sprawl. This trend reduces opportunities for physical activity for members of the school community, because students must be bused to school or driven by family members. Research shows that whether schools are new or old, parents are concerned about safety, injury, and crime, which can cause them to limit physical activity opportunities for their children if they perceive the school environment to be unsafe.

KINESIOLOGY AND PHYSICAL ACTIVITY OUTCOMES FOR YOUTH Selected chronic adaptations to physical activity and exercise are listed in the highlight box Adaptations to Physical Activity and Exercise Programming for Youth. The amount of physiological adaptation related to each of the identified benefits is dose dependent and influenced by the physical training principles

discussed in chapter 2 and reviewed by Strong and colleagues (2005).

The exercise science–related benefits of physical activity for children, adolescents, and young adults are highly dependent on individual growth and development. Most youth experience very positive benefits associated with engaging in physical activity and exercise; however, maturation can influence the rate and timing of specific training adaptations.

ADAPTATIONS TO PHYSICAL ACTIVITY AND EXERCISE PROGRAMMING FOR YOUTH Physiological

Increased O2max Increased strength

Improved muscular endurance

Increased HDL levels

Lower triglyceride levels

Improved insulin levels

Lower blood pressure

Lower percentage of body fat

Reduced risks for metabolic dysfunction

Reduced risks for type 2 diabetes

Improved bone health

Biomechanical

Improved economy with age

Improved balance

Improved mobility

Increased motor skill and confidence to engage

further in physical activity and exercise

Improved proprioception

Behavioral

Increased self-confidence

Improved self-efficacy

Improved self-esteem

Decreased depression and anxiety

Experience with behavioral change

Physiologically, participation in regular physical activity can help youth increase cardiorespiratory endurance ( O2max or O2peak) by 8 to 10%. Children and adolescents can increase their strength and muscular endurance; however, strength gains prior to puberty are mostly due to neural changes (i.e., better muscle recruitment) rather than hypertrophy (i.e., increased muscle size). There are published recommendations that pertain to youth strength and muscular endurance training (see Kenney, Wilmore, and Costill 2020 for more).

Youth can achieve significant and consistent improvements in bone health by participating in weight-bearing and muscular strength and endurance activities. The opportunity for increased bone mass in girls and boys occurs in premenarche and puberty. Their risks for metabolic dysfunction (e.g., issues related to HDL, triglyceride, and insulin levels; blood pressure; and percentage of body fat) and type 2 diabetes are also significantly reduced if they can get 60 minutes or more of physical activity daily.

Youth can experience many of the same biomechanical benefits reported for adults and older adults, particularly if they have the opportunity to develop a range of motor skills by participating in a variety of physical activities. As children move through adolescence to young adulthood, they experience improved economy (i.e., lower energy cost) in activities such as running. Changes in economy have been attributed to changes in body size and perhaps in stride frequency.

Youth engaged in organized sports have been reported to suffer more injuries that might limit future physical activity (particularly if they do not participate safely with protective equipment) than nonparticipants. However, except for information from descriptive studies of high school athletes, there is little evidence for this claim. Research on participation in school-based PE suggests that it is a very safe undertaking for the vast majority of students participating.

Behaviorally, the experiences that children (including pre-K and kindergarten students) have with physical activity, and the early behaviors that they develop as a result of participation, are thought to be critical to whether they become and remain active through adolescence and adulthood. Those who do not have the opportunities to develop the motor skills by participating in a variety of physical activities (as part of leisure time, recreation, PE, sports, and games) are most likely to become inactive, obese, or overweight adolescents, adults, and older adults.

SCHOOL-BASED PHYSICAL ACTIVITY AND PHYSICAL FITNESS ASSESSMENTS OF YOUTH A discussion of all the physical activity and fitness assessments that pertain to children and adolescents is beyond the scope of this text (see Morrow 2009 for more). However, it is important to point out that the assessment techniques discussed in chapter 4 have been used extensively in school-based physical activity intervention evaluations.

Two frequently used comprehensive fitness assessment programs are Fitnessgram and the Presidential Youth Fitness Program. They are comprehensive field assessments of physical fitness in children and adolescents, and both contain a variety of valid and reliable fitness tests (that provide teachers with options and advice), with age-appropriate interpretations, and strategies and programming to increase or maintain physical activity. Fitnessgram and the Presidential Youth Fitness Program are school friendly and can be used as in-service programs for teachers and health professionals.

Fitnessgram was first developed in 1982 by the Cooper Institute in response to the need for a comprehensive set of assessment procedures for PE programs. The assessment includes health- related physical fitness field tests that assess aerobic capacity; muscular strength, muscular endurance, and flexibility; and body composition. Scores from these assessments are compared to healthy fitness zone standards to determine students’ overall physical fitness levels, and areas for improvement are suggested when appropriate. An activity assessment included in the Fitnessgram software enables students to record their physical activity over time during the school day, and generates a report showing the total minutes of activity, periods of activity time each day, and types of activity.

The mission of the President’s Council on Sports, Fitness and Nutrition is to increase sports participation among youth of all backgrounds and abilities, and to promote healthy and active lifestyles for all Americans. The Presidential Youth Fitness Program is a comprehensive school-based program that promotes health and physical activity for America’s youth. The program includes online challenges and allows participants to keep track of their progress toward individual goals.

Although many have argued that physical fitness tests should be abandoned in schools, physical fitness testing of youth seems to have gained momentum in recent years; California and Texas both mandate fitness testing of students in several grades. The idea is that testing health-related fitness parameters will help integrate behavior, fitness, motor skills, and cognition to encourage more physical activity in and out of school. Policy makers have used fitness evaluation results, at least in part, to make the case that children and adolescents score low on health-related fitness, and therefore need to become more active and fit.

McKenzie (2007), Morrow (2005), and others have reviewed the numerous pitfalls associated with youth fitness testing, particularly in school PE. For public health practitioners, the most notable point to

remember is that the relationship between measures of physical fitness (i.e., physiological constructs) and physical activity (behavior) is relatively weak. Further, youth fitness performance is influenced by genetics, growth and development, and maturation. Thus, very inactive children may do very well on school field tests of physical fitness, whereas others who may be meeting or exceeding the guideline of 60 minutes per day may not do well on some or all of the tests. It remains to be determined whether physical fitness testing of children and youth promotes more physical activity in these groups, and whether the strategy has a significant impact on the prevalence of obesity, overweight, and diabetes.

Do children and adolescents like competition in school PE? Does it help promote physical activity? Why?

PHYSICAL ACTIVITY IN CHILDREN AND ADOLESCENTS Important considerations concerning physical activity promotion in children and adolescents are their individual growth trajectories and the fact that older children have more developed motor skills than younger ones. We all know that some children mature faster than others. This results in differences in motor ability among individuals

of similar ages as well as across the age range. Fourteen-year-olds have better gross motor control, more muscle mass, and generally higher fitness than younger children, for example. This difference in physical abilities due to growth and development can affect many aspects of physical activity behavior, both physical and psychological.

Changes in motor ability for a number of fitness parameters are illustrated in figure 12.2 for youth ages 6 to 17. Clearly, children at different ages differ in their test results that measure flexibility, muscular strength, and aerobic fitness. Further, sex differences are to be expected, particularly as children grow into adolescence. The data in this figure illustrate that many physical performance outcomes for youth are related to growth, development, and maturation, and they vary by sex. Understanding the interrelationships among growth, maturation, and exercise is critical for designing and implementing meaningful physical activity programs for children and adolescents.

SCIENTIFIC EVIDENCE The 2008 Physical Activity Guidelines Advisory Committee (PAGAC) found that strong scientific evidence supported a consistent effect of physical activity and exercise on cardiorespiratory fitness and muscular strength in children and adolescents ages 6 to 17 (U.S. Department of Health and Human Services [USDHHS], PAGAC 2008). They also found strong evidence that physical activity and exercise are positively associated with body composition, cardiorespiratory and metabolic health, and bone health; higher levels of physical activity are associated with more favorable outcomes. The evidence correlating to mental health benefits (now referred to as brain health) for active youth was moderate for depression, weak for anxiety, and limited for self-esteem.

Figure 12.2   Changes in motor ability from the ages of 6 years to 17 years. Reprinted by permission from J. Wilmore, D.L. Costill, and L.W. Kenney, Physiology of Sport and Exercise, 5th ed. (Champaign, IL: Human Kinetics, 2012), 441. Data from the President’s Council on Fitness and Sports 1985.

The 2018 PAGAC additionally focused on the scientific evidence between physical activity and health outcomes for children under 6 years of age and the health outcomes of sedentary behaviors for children and adolescents. The findings of the 2018 PAGAC report are more robust than the 2008 PAGAC, but confirm and extend the recommendations for daily physical activity for children and youth, ages 3 to 17.

Strong evidence indicated that higher amounts of physical activity were associated with more favorable indicators of bone health and with reduced risk for excessive increases in body weight and adiposity in children ages 3 to 6 years. Insufficient evidence was available to determine the effects of physical activity on cardiometabolic risk factors, the dose for health effects, or moderating factors like age, sex, race, ethnicity, weight status, or socioeconomic status in children under 6 years of age,

The 2018 PAGAC updated evidence for 6 to 17 year olds with regard to physical activity and health outcomes, supporting the 2008 PAGAC except for finding moderate (as compared to strong) evidence for physical activity and cardiometabolic health. Additionally, the committee found that children and adolescents who engage in regular moderate-to-vigorous physical activity significantly increase their cardiorespiratory fitness, and those participating in resistance training significantly increase their muscular fitness.

Evidence of a dose-response relationship between physical activity and exercise and cardiorespiratory and metabolic health in youth has not been specifically determined, and more dose- response studies are needed for evaluating other health outcomes in youth. There is strong evidence that physical activity and exercise has positively affected youth fitness levels for boys and girls. Evidence of effects of age, sex, and race or ethnicity on body composition, cardiorespiratory and metabolic health, and mental health in youth is unclear. A strong association has been shown between physical activity and exercise and bone health for both boys and girls, and it is influenced by growth, development, and maturation. Children should initiate physical activity at least by the early teen years to maximize physiological benefits.

Many studies have demonstrated significant gains in physical fitness measures (cardiorespiratory and muscular) in children and adolescents who participated (60 minutes per day recommended) in moderate- to vigorous-intensity aerobic activities three or more days per week, and muscle-strengthening and bone-strengthening

exercises two or three days per week. Cardiorespiratory and metabolic health are also significantly improved by taking part in vigorous-intensity aerobic activities at least three days per week, and bone health also responds positively to weight-bearing activities performed at least three days per week.

With regard to time spent by youth in sedentary behaviors, the 2018 PAGAC found limited evidence for poorer health outcomes in children and adolescents. The evidence was somewhat stronger for various health outcomes for television viewing or screen time than for total sedentary time.

GUIDELINES The guidelines for physical activity for youth were initially highlighted in chapter 5. The 2018 edition of Physical Activity Guidelines for Americans includes new recommendations for preschool-aged children to acquire three or more hours of light, moderate, and vigorous physical activity daily:

Preschool-aged children (ages 3 to 5) should be physically active throughout the day to enhance growth and development. Adult caregivers of preschool-aged children should encourage active play that includes a variety of activity types. In addition, children and adolescents (ages 6 to 17) should engage in at least 60 minutes per day of moderate- or vigorous- intensity physical activity (including aerobic, muscle- strengthening, and bone-strengthening activities) for at least three days per week. Youth should be provided opportunities and encouragement to participate in physical activities that are age-appropriate, enjoyable, and offer variety.

It is also important to know some strategies for replacing inactivity with activity. Following are some suggestions for getting youth active and encouraging them to stay active by meeting the guidelines (USDHHS, PAGAC 2008, 2018):

Children and adolescents who are inactive or doing less physical activity than the guidelines suggest should slowly increase their moderate-to-vigorous physical activity in ways they enjoy. A gradual increase in the number of days and the time spent being active will reduce the risk of injury and is consistent with the basic principles of exercise physiology covered in chapter 2. Children and adolescents who meet the recommended guidelines should continue doing moderate-to-vigorous physical activity on a daily basis and, if appropriate, become even more active. Evidence suggests that more than 60 minutes of activity per day may provide additional health benefits. Children and adolescents who exceed the guidelines should maintain their activity level and vary the kinds of activities they do to reduce the risk of overtraining or injury. Youth with disabilities will most likely be less active than those without disabilities and should specifically be encouraged to work with healthcare professionals to incorporate physical activity into their lifestyles, using adjustments to accommodate their physical and mental challenges. They should be also encouraged to do as much physical activity as possible to achieve the guidelines and avoid being inactive.

INTERNATIONAL AND NATIONAL TRENDS IN YOUTH PHYSICAL ACTIVITY LEVELS As you have learned in previous chapters, physical inactivity and insufficient activity to meet current recommended physical activity levels are associated with increased mortality (fourth leading noncommunicable cause of death). However, engagement in regular physical activity has been shown to be a key factor for physical, physiological, developmental, mental, cognitive, and social health for children and adolescents. Yet it is estimated that 80% of youth (ages

11-17) worldwide do not obtain the recommended 60 minutes of moderate-to-vigorous physical activity daily (Sallis et al. 2016).

The Global Matrix initiative is part of an incorporated nonprofit organization that includes collaborating researchers, health professionals, and stakeholders to provide assessment and awareness of physical activity in children and older youth globally (Aubert et al. 2018). The results of a Global Matrix Report Card based on 10 indicators of physical activity (overall physical activity, organized sport and physical activity; active play; active transportation; sedentary behaviors; physical fitness; family and peers; school, community and environment; and government) for youth in 49 countries were published in 2018. Data from 49 countries were analyzed based on the physical activity indicators and classified into three categories using the United Nation’s human development index (HDI) of low and medium, high, and very high. Overall, average grades of C-, D+, and C- respectively were reported for low and medium HDI countries, high HDI countries, and very high HDI countries. The HDI is based on varying education, life expectancy, and income per capita data in countries globally.

The results of the Global Matrix initiative study provide specific worldwide data about indicators of youth physical activity. The data presents public-health physical activity practitioners with insight for future development of effective strategies to increase physical activity opportunities for youth.

In the United States, Katzmarzyk and colleagues (2018) have summarized the results of the 2018 U.S. Report Card on Physical Activity for Children and Youth. The data were collected as part of the National Physical Activity Plan with various national data resources, and used the same indicators as those described previously for the Global Matrix initiative. The authors also provided rationales for the ratings which can be found in their report. The following grades were assigned for 10 indicators:

Overall physical activity: D-

Sedentary behaviors: D Organized sport participation: C Active play: Incomplete (based on insufficient data) Active transportation: D- Physical fitness: C Family and peers: D- School: D- Community and environment: C Government: Incomplete (no data)

As you can see, the authors found poor grades for the 2018 U.S. Report Card on Physical Activity for Children and Youth that indicates insufficient participation in physical activity. The results (with rationales for each indicator) provide U.S. public-health physical activity practitioners with evidence-based data (in addition to international data) to develop effective strategies to increase opportunities for physical activity among children and youth.

SCHOOL-BASED PHYSICAL EDUCATION Since the early 1990s, school PE programs have focused on health- related PE (HRPE) (McKenzie 2007). The HRPE concept promotes public health objectives and focuses on the health benefits of physical activity. This focus on behavior rather than physiological status is important because for many years, school PE was primarily focused on sport performance and yearly fitness testing. Students were usually not prepared for the fitness tests; therefore, they scored poorly and became turned off to becoming fit. In fact, many of today’s public policy makers themselves experienced PE in “a setting in which embarrassment, humiliation, anger, discomfort, noninvolvement, apathy, rebellion, compliance, and irrelevant behavior appear to be the norm” (Massengale 1987). Perhaps it is not too hard to understand why resistance to promoting school PE through HRPE continues, both inside and outside the PE profession.

Can participating in youth sports promote physical activity and exercise for a lifetime?

As covered in chapter 11, the Community Guide (Kahn et al. 2002; Community Preventive Services Task Force 2014) is a resource for evidence-based disease prevention and health- promotion strategies. One of the strategies that works is high-quality physical education. Outcomes of interest in studies of PE include the amount of time (days per week and minutes per period) as well as the amount of time per period that students spend being physically active in PE class. Additionally, physiological outcomes such as improvements in physical fitness and changes in body composition have been investigated. The studies of the effectiveness of school PE in increasing physical activity suggest the following:

The amount of time spent in moderate- or vigorous-intensity physical activity during PE class should be increased by using instructional strategies that extend physical activity time (e.g., modifying rules of game, substituting less active games with more active ones). Time spent in moderate- or vigorous-intensity physical activity has been shown to increase on average about 10%.

Physical education lesson plans should incorporate fitness and other training activities.

These recommendations have been evaluated in studies that have involved lengthening the time period of existing PE classes, adding new PE classes, and increasing the amount of time dedicated to moderate- to vigorous-intensity physical activity during class without lengthening class time.

Crucial to the Community Guide recommendations for PE is the use of high-quality studies. The studies reviewed were not those in which a ball was rolled out during a PE period or students were lined up to shoot basketballs one at a time. Instead, the Community Guide recommendations are based on studies of high-quality PE programs that include all students, have appropriate class sizes, use developmentally (age-) appropriate curricula delivered by trained PE specialists, have adequate equipment to meet educational goals, focus on an appropriate mix of motor skills, increase student understanding, and provide active opportunities to practice. These characteristics (and others) are encouraged by SHAPE America, the primary association for physical education professionals in the United States. PE works when it is high-quality PE. The training of new PE professionals who can integrate the modern concepts of PE and public health are better prepared to deliver effective physical activity programs (Murray et al. 2019).

Several commercial school-based PE programs are available to enhance the PE curricula of primary, middle, and secondary schools. Most of these programs have been tested with positive results. A list of these resources is found in the web resource.

Physical education is not the only aspect of health that schools can affect. Because such a large proportion of children are enrolled in schools, it is a logical place to help them learn and practice healthy behaviors. The primary public health framework for promoting school health, including increased physical activity, is the Whole School, Whole Community, Whole Child (WSCC) Model

developed by the CDC and the Association for Supervision and Curriculum Development. The WSCC Model consists of the following 10 interactive components:

Health education Physical education and physical activity Nutrition environment and services Health services Counseling, psychological, and social services Social and environmental climate Physical environment Employee wellness Family engagement Community engagement

From CDC, www.cdc.gov/healthyyouth/wscc/model.htm.

OPPORTUNITIES FOR SCHOOL-RELATED PHYSICAL ACTIVITY Despite the fact that schools are a helpful place to promote physical activity because of the sheer numbers of students there, even the best PE classes cannot provide the entire recommended 60 minutes per day of physical activity that children and adolescents need. The Comprehensive School Physical Activity Program (CSPAP) is a school-based, multicomponent approach that is designed to increase physical activity. Enhanced PE is the foundation of CSPAP but it also includes before- and after-school programs; in-class physical activity breaks; physically active learning activities, and connections to family and community resources (Pate and Dowda 2019). Many of these strategies are showing promise in adding physical activity opportunities to the day for children and adolescents, but the full impact of CSPAP’s five components for increasing physical activity remains to be determined.

CASE STUDY

THE SPARK PROGRAM The Sports, Play, and Active Recreation for Kids (SPARK) program is a comprehensive health-related PE program for elementary school children. The program promotes the use of enjoyable physical activities during PE classes coupled with teaching movement skills. Children are active in moderate- or vigorous-intensity physical activity for most of a PE class period; approximately 50% of the time is devoted to health-related physical activity, and 50% to skill building. In addition to the weekly modules in health-related physical activity and skill-related sports, the program also includes an emphasis on self-management skills and homework designed to engage parents.

In their evaluation of the program, Sallis and colleagues (1997) randomly assigned seven schools (nearly 1,000 elementary school students) to the SPARK program or the usual PE program (control). The SPARK schools were further randomly assigned to one of two conditions: one in which PE classes were led by trained PE specialists, and the other in which PE classes were led by classroom teachers with no special training in PE. After two years of implementation, schools with the SPARK program achieved significantly more minutes per week of physical activity during PE classes than did the control schools (see figure 12.3). Further, students in classes that were led by trained PE specialists spent the most time being physically active. High-quality physical education promotes physical activity.

Figure 12.3   Effects of a health-related physical education program (SPARK) on minutes per week of physical activity in elementary school children. Adapted from Sallis et al. (1997).

DEVELOPMENTAL CONSIDERATIONS FOR PHYSICAL ACTIVITY IN YOUTH The maturation, growth, and development factors (roughly, although not perfectly, estimated by the child’s age) that affect physical fitness and were discussed earlier have implications for strategies to promote physical activity among children and adolescents. Clearly,

different approaches are needed depending on age, sex, and developmental stage. High-quality school PE curricula should take such differences into account. Figure 12.4 shows how the emphasis of PE programs should change as children mature.

During the preschool and elementary school years, the emphasis of PE programs should be on engaging in general physical activity that develops and improves motor skills (locomotor, such as traveling, fleeing, and dodging; nonmanipulative, such as jumping, landing, and balancing; and manipulative, such as kicking, throwing, and catching). Participation in activities that develop physical competence, offer choices, maximize fun and enjoyment, and minimize anxiety (e.g., games and lead-up sports) can positively influence children’s activity levels.

Figure 12.4   Changing emphasis of physical activity during childhood and adolescence. Adapted by permission from R.J. Park and M.H. Eckert, eds., New Possibilities, New Paradigms? American Academy of Physical Education Papers 24. (Champaign IL: Human Kinetics, 1991), 30-38.

Once students reach the ages of 10 to 14, the emphasis on physical activity should shift toward individual and group activities, including school and club sports. Because time in school PE usually decreases for this age range, teachers should focus on factors that encourage youth to adopt and maintain physical activity levels, such as the following:

Being active with friends Having fun and developing the skills needed for performing activities of choice Having time for physical activities at which they feel competent Sharing time with adults who are positive role models for physical activity Access to neighborhood facilities to engage in leisure-time activities Good parent–adolescent communication Self-esteem Access to equipment

For older adolescents (ages 15 to 18), more structured physical activity programs that help them transition toward adulthood are recommended. This age group is quite vulnerable to becoming sedentary, losing caloric balance, and gaining weight rapidly as they become more independent. The emphasis for young adults should be on health, fitness, and behaviors that can be adopted and maintained in adulthood. Those attending community colleges or universities should be encouraged to participate in physical activity classes to establish or maintain skills for active living.

In summary, numerous methods have been, or can be, implemented in schools to increase students’ physical activity levels. Although high-quality PE is the primary evidence-based strategy that has been shown to increase physical activity, others have been investigated and are showing promise. High-quality PE programs delivered by trained physical educators seem to have the greatest

impact on physical activity in schoolchildren. The evidence that physical activity and physical fitness can positively affect academic achievement is accumulating, but the cost-effectiveness of school- based PE and physical activity interventions has not been evaluated. Fortunately at the present time, public health physical activity practitioners have numerous resources (e.g., HP 2020, NPAP, CSPAP, IOM 2013, and the Community Guide) to assist them in the development and implementation of school-based physical activity programming.

LEADER PROFILE Peter Silvius, MS

Why and how did you get into the field of Physical Activity and Public Health? This is the 20th year that I have worked in public education. My first job was in adapted physical education, and I quickly learned how movement and play could support happiness. I had always been intrigued by the correlation of physical activity and social-emotional wellness. This interest led me to focus on issues related to student behavior, learning readiness, and facility design. I have found that if access to physical activity is intentionally established as a foundation, our expected outcomes will be more attainable and sustainable.

Did any one person have a major influence on your career? How? I have had several mentors in my life that continue to be major influences on my understanding of the world and my role and responsibility within it—Dr. Bill Squires is one of these mentors. Dr. Squires has helped me to understand the importance and responsibility of a public school for our communities, and that the public school is “sacred

ground” where we seek equity and safety for all. What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? In the school district where I work we recently adopted a new policy to increase recess time for all elementary students by providing unstructured outdoor play before every hour of lesson time. I believe that this change is going to be transitional for our community and will benefit the educational and health outcomes for our students and improve community wellness as a whole. With our new approach, all elementary students will have access to an hour of outdoor, unstructured recess every day in addition to their scheduled physical education class.

Why do you do what you do? The people I work with motivate me as does the community of students and citizens I work for. When asked about my work, I often respond, “I get to do all the fun stuff—the foundational stuff that really matters.” After 20 years in the field, I now see the fruits of my efforts and I have a clear sense of my core values. I feel proud of the many small gains that we have made in my home school district and I look forward to building on these successes in the future.

What are two key issues that must be addressed by 2030? We must continue our efforts to reengineer activity into our lives. In most communities we have made driving a car the safest and easiest option for even the shortest trips. We must make walking and biking easier and safer by means of bike lanes and sidewalks. These changes can be easy to make if resources are directed toward active transportation.

Our schools need to address lifelong recreation skills. Our secondary physical education programs need to focus skill development on lifelong forms of recreation. Team- sport–related skill development does not provide the skills needed for a lifetime of activity. We need to teach our children to understand the benefits of outdoor recreation and to understand the need for fresh air and natural spaces as a vital aspect of our physical, social, and emotional health.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

In the United States, over 56.6 million children and adolescents attend public and private elementary and secondary schools, where they spend approximately 6.5 hours per day for an average of 180 days per year. Additionally, over 1.4 million children attend pre-K schools, and more than 12.2 million older adolescents and young adults (< 25 years) attend community colleges or universities. This makes schools very attractive environments in which to promote physical activity. There is no evidence that time spent in physical activity or PE has negative influences on academic achievement, and emerging evidence suggests that physical activity positively influences academic achievement. The primary Whole School, Whole Community, Whole Child (WSCC) components that U.S. educators are encouraged to use to promote increased school physical activity are health education; physical education and physical activity; nutrition environment and services; health services; counseling, psychological, and social services; social and emotional climate, physical environment; employee wellness; and community involvement.

The Community Guide recommends high-quality school PE as an evidence-based strategy to promote physical activity. The health-related PE (HRPE) concept promotes public health objectives and encourages students to become more physically active, rather than just focusing on physical fitness, which was the desired product or outcome of PE in the past. In addition to PE, schools can increase youth physical activity levels through before-school programs, classroom activity breaks, recess breaks, after-school programs, sports and intramural programs, and summer (seasonal) programming. During the preschool and elementary school years, school- based programs to increase physical activity should emphasize general physical activity and improving the motor skills (locomotor, such as traveling, fleeing, and dodging; nonmanipulative, such as jumping, landing, and balancing; and manipulative, such as kicking, throwing, and catching). Once students reach the ages of 10 to 14, the emphasis should shift toward a variety of individual and group activities, including school and club sports. The emphasis for young adults should be on health, fitness, and behaviors that can be adopted and maintained into adulthood. The exercise-related benefits for children, adolescents, and young adults are highly dependent on individual growth and development. Most youth can experience the very positive benefits of engaging in physical activity and exercise; however, maturation can influence the rate and timing of these training adaptations. The guidelines for physical activity participation for preschool- aged children (ages 3 to 5) encourage physical activity (light, moderate, and vigorous activities) throughout the day for up to three hours or more to enhance growth and development. Children and adolescents ages 6 to 17 should engage in at

least 60 minutes per day of moderate- or vigorous-intensity physical activity (including aerobic, muscle-strengthening, and bone-strengthening activities) for at least 3 days per week.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Aubert A, Barnes JD, Abdeta C, Nada PA, Adeniyi AF. et al. 2018.

Global Matrix 3.0 physical activity report card grades for children and youth: Results and analysis from 49 countries. Journal of Physical Activity and Health 15 (Suppl 2): S251- S273.

Centers for Disease Control and Prevention (CDC). Comprehensive School Physical Activity Programs. 2019. https://www.cdc.gov/healthyschools/professional_development/ e-learning/cspap.html. Accessed July 2019.

Community Guide. 2019. The Guide to Community Preventive Services https://www.thecommunityguide.org/topic/physical- activity. Accessed 18 January 2019.

Community Preventive Services Task Force. 2014. Physical Activity: Enhanced School-Based Physical Education. Community Guide. https://www.thecommunityguide.org/topic/physical-activity. Accessed 10 March 2019.

Healthy People 2020. 2010. www.healthypeople.gov/2020/default.aspx. Accessed 18 January 2019.

IOM (Institute of Medicine). 2013. Educating the Student Body: Taking Physical Activity and Physical Education to School. Washington, DC: The National Academies Press.

Kahn EB, Ramsey LT, Brownson RG, et al. 2002. The effectiveness of interventions to increase physical activity. American Journal of Preventive Medicine 22: 73-107.

Katzmarzyk PT, Denstel KD, Beals K, Carlson J, Crouter SE et al. 2018. Results from the United States 2018 report card on physical activity for children and youth. Journal of Physical Activity and Health 15 (Suppl 2): S422-S424.

Kenney L, Wilmore J, Costill D. 2012. Physiology of Sport and Exercise, 5th ed. Champaign, IL: Human Kinetics.

Kenney L, Wilmore J, Costill D. 2019. Physiology of Sport and Exercise, 7th ed. Champaign, IL: Human Kinetics.

Lee S, Wechsler H, Balling A. 2006. The role of schools in preventing childhood obesity. Research Digest 7 (3): 1-8.

Massengale JD, ed. 1987. Trends Towards the Future in Physical Education. Champaign, IL: Human Kinetics.

McKenzie T. 2007. The preparation of physical educators: A public health perspective. Quest 259 (4): 345-357.

Morrow JR Jr. 2005. Are American children and youth fit? It’s time we learned. Research Quarterly for Exercise and Sport 76: 377-388.

Morrow JR, Zhu W, Franks D, Meredith M, Spain C. 2009. 1958- 2008: 50 years of youth fitness tests in the United States. Research Quarterly for Exercise and Sport 80: 1-11.

Murray TD, Eldridge JA, Kohl HW III 2019. Foundations of Kinesiology: An Integrated Approach. Boston, MA: Cengage.

Park RJ, Eckert MH, eds. 1991. New possibilities, new paradigms? American Academy of Physical Education Papers

24: 30-38. Pate RR, Dowda M. 2019. Raising an active and healthy

generation: A comprehensive public health initiative. Exercise and Sport Science Reviews 47: 3-14.

Robert Wood Johnson Foundation. 2009. Active Living Research, Active Education, Physical Activity, and Academic Performance. www.activelivingresearch.org. Accessed 14 July 2011.

Sallis JF, Bull F, Guthold R, et al. 2016. Progress in physical activity over the Olympic quadrennium. Lancet: 388 (10051): 1325-1336.

Sallis JF, McKenzie TL, Alcarez JE, Kolody B, Faucette N, Hovell MF. 1997. The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students. American Journal of Public Health 87: 1328-1334.

Siedentop D. 2009. National plan for physical activity: Education sector. Journal of Physical Activity and Health 6 (Suppl): S168- S180.

Strong WB, Malina RM, et al. 2005. Evidence based physical activity for school-age youth, Journal of Pediatrics 146: 732- 737.

U.S. Department of Health and Human Services. 2008. Physical Activity Guidelines for Americans. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/PAGuidelines.

U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2008. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC:

U.S. Department of Health and Human Services. https://health.gov/paguidelines/2008/report/pdf/CommitteeRepo rt.pdf.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.1, 1.4.1, 1.4.2, 2.1.1, 2.1.3, 2.2.1, 2.2.2, 2.2.3, 3.4.2, 4.2.2, 4.5.3, 4.5.4, 6.2.1, 6.2.3, 6.4.1, 6.4.4

CHAPTER 13 Behavioral and Social Approaches to Understanding and Promoting Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The key behavioral theories and theoretical models used to explain physical activity behavior

»  The definitions of behavioral and social approaches to physical activity promotion

»  The rationale for promoting physical activity using behavioral and social approaches

»  Evidence-based strategies for behavioral and social approaches to physical activity promotion

»  Examples of each kind of evidence-based strategy

OPENING QUESTIONS Almost everyone cycles in and out of being physically active. Some weeks are good; others are not. Weeks turn into months and then into years. Life circumstances and demands have a way of shifting priorities.

»  Has this ever happened to you? Have you had to change or stop an exercise routine because of life changes? How did you work through it? What strategies did you use to continue to make physical activity a priority?

»  Has this ever happened to someone in your family, or a close friend? What were the barriers for this person continuing to be physically active?

»  Alternatively, have you ever wondered how someone can be physically active day after day, year after year? Why are these people successful?

Understanding the behavioral and social approaches as to why people are physically active, and consequently, to the promotion of physical activity itself, relies on individual-level strategies, skills for behavior change and maintenance, and the structure of the social environment (as opposed to the physical environment). Historically, much of the early scientific work in physical activity promotion used individual behavioral approaches. More recently, strategies targeting the social environment of individuals have begun to emerge. These strategies, with their roots in psychology, behavioral science, and social psychology, have helped identify the ways people improve many health behaviors, not just physical activity.

BEHAVIORAL THEORIES AND THEORETICAL MODELS OF BEHAVIOR CHANGE Behavioral scientists rely on theories and theoretical models to explain and predict health behaviors, and explain changes in those behaviors and their maintenance. These theories and theoretical models are very important for understanding why some individuals are active and others are not, and for guiding individual-focused programs and promotion projects for physical activity. Such theoretical models typically are used to determine what can be expected from helping individuals adopt the skills they need to begin or continue physical activity.

Five popular behavior theories and theoretical models that have been used to explain and predict the physical activity behavior of individuals are depicted in table 13.1. This table shows the name of the theory or model, key behavioral constructs that the theory or model seeks to modify or support, and a brief explanation of the theory or model.

Although a complete treatment of each aspect of these theories and models is beyond the scope of this textbook, it is important to be familiar with them and with the constructs they are designed to influence. One popular example, the transtheoretical model, is presented here. Different scientists prefer different behavior change theories or models. Unfortunately, no single theory or model has been proven to excel in its ability to predict behavior change and maintenance. Each has strengths and weaknesses based on the varying effects of the physical and policy environment on individual behavior. Chapter 14 provides a more in-depth discussion of the built environmental and policy influences on physical activity behavior.

The transtheoretical model presents a behavioral continuum and addresses how people may move along that continuum to help develop ideas about how to change physical activity behavior. Fundamentally, a person is classified into one of five behavioral stage categories—from not being ready to change or begin physical

activity at all to maintaining that behavior for an extended period of time. The idea behind the transtheoretical model is that knowing where a person is along the continuum of behavior change makes it theoretically easier to understand how that person could increase physical activity behavior and the processes through which those changes could occur. The transtheoretical model was first developed to explain smoking-cessation behavior, but it has been extrapolated to other health behaviors. It is one of the more frequently used models in physical activity intervention studies.

Table 13.1   Popular Behavioral Theories and Theoretical Models for Physical Activity Behavior

Theory or model Key behavioral constructs Explanation

Health belief model (Janz et al. 2002)

Perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, self-efficacy

People become physically active if they feel at risk for a negative health outcome (i.e., perceived susceptibility and severity), expect that by being physically active they will prevent that negative health outcome (i.e., perceived benefits), and believe that they can initiate and maintain the physical activity (i.e., perceived barriers, self- efficacy).

Theory of reasoned action/theory of planned behavior (Azjen 1991)

Attitudes, subjective norms, behavioral control, behavioral intention

People’s intentions to be physically active depend on their beliefs about physical activity weighted by evaluations of these beliefs (i.e., attitudes), the beliefs of other people about physical activity weighted by the value attributed to these opinions (i.e., subjective norms), and the perceived ease or difficulty of being physically active (i.e., perceived behavioral control). People who intend to become physically active are likely to do so.

Social cognitive theory (Bandura 1986)

Reciprocal determinism, environment, outcome expectancies, observational learning, reinforcement, self-efficacy

Reciprocal relationships exist among the environment, personal factors (e.g., beliefs), and physical activity. Beliefs (i.e., outcome expectancies, self- efficacy) can influence actions, and vice versa. Beliefs are molded by structures within the social and physical environment. Physical activity can influence the environment and is determined by that environment. These processes occur through observational learning and reinforcement.

Self- determination theory (Ryan and Deci 2000)

External regulation, introjected regulation, identified regulation, integrated regulation, intrinsic motivation

Actions vary in the degree to which they are volitional, without any external influence. Motivation to be physically active occurs along a continuum from external regulation (i.e., rewards, others’ demands), to introjected regulation (i.e., moral reasons), to identified regulation (i.e., useful outcomes), to integrated regulation (i.e., important for personal growth), to intrinsic motivation (i.e., mastery, enjoyment).

Transtheoretical model (Prochaska

Stages of motivational

People progress through five stages of change on the way to being physically

and DiClemente 1983)

readiness for change, processes of change

active: precontemplation, contemplation, preparation, action, and maintenance. Processes of change are activities that people use to move through the stages: consciousness raising (increasing awareness), dramatic relief (emotional arousal), environmental reevaluation (social reappraisal), social liberation (environmental opportunities), self- reevaluation (self-reappraisal), stimulus control (reengineering), helping relationship (supporting), counter conditioning (substituting), reinforcement management (rewarding), and self- liberation (committing).

Adapted from Dunton et al. (2010).

FROM INDIVIDUALS TO POPULATIONS Social and behavioral approaches to physical activity promotion have historically and necessarily focused on changing or maintaining the exercise behaviors of individuals. As we learned in the first part of this textbook, public health focuses on populations and to a lesser degree on individuals. Why then are behavioral and social approaches of interest if they focus on a person- by-person strategy? The answer is that we can learn a substantial amount about how to change populations by understanding how individuals can (and do) change. Although behavioral and social approaches may not strictly be recommended for population-wide changes in physical activity, they do provide a useful point at which to begin because populations are composed of individuals. Understanding the system dynamics that influence individual behavior changes on a population level becomes the missing link.

A graphic description of the transtheoretical model as it relates to physical activity is shown in figure 13.1. The continuum of behavior has five categories that are used to classify how prepared a person is to change behavior, or motivational readiness. The first is precontemplation, in which a person has not even thought about

becoming physically active or may be unaware of the importance of being physically active. The second category, or stage, is contemplation. Here, a person may be thinking about making a change to be physically active a short time in the future, and may be aware of the health benefits, but has not yet reached a tipping point to make the behavior change. The third stage, preparation, is when a person has reached that tipping point and is making small changes in behavior (e.g., taking the stairs rather than the elevator). Support from friends and family may also be needed as this new stage of activity begins. Action is the fourth stage of the transtheoretical model. Here, a previously sedentary person has recently become physically active and is perhaps meeting the U.S. physical activity guidelines of 150 minutes per week of moderate-intensity physical activity. Finally, the maintenance stage indicates that a person has been consistently active for at least six months.

Knowing people’s stages of readiness helps practitioners tailor behavioral intervention programs to match those stages. For example, people in the preparation stage should be encouraged to action by giving them more reasons to exercise and fewer reasons to be sedentary. Strategies that are useful in the precontemplation stage include teaching about the health benefits of exercise, the reasons for being physically active, and how to meet the minimal physical activity guidelines. People at this stage should also be educated about the risks of being inactive. Clearly, these strategies would be of little use to those in the preparation or action stage because they would have already acquired this knowledge.

Although strategies for behavior change may differ depending on the stage, two overriding concepts that are relevant at each stage of motivational readiness are decisional balance and self-efficacy. Decisional balance refers to a person’s ability to weigh the pros and cons of being physically active and to take action based on that assessment. Typically, the cons outweigh the pros in the precontemplation and contemplation stages, whereas the pros should outweigh the cons in the action and maintenance stages.

Figure 13.1   The transtheoretical model of health behavior change for physical activity. Adapted from Marcus et al. (1992).

Self-efficacy in physical activity behavior refers to the confidence or perceived ability that a person may have to be physically active and deal with the external threats and barriers that could result in slowing, stopping, or reverting progress. Research has identified self-efficacy as a key construct of several of the health behavior theories in table 13.1. Strategies at each stage of motivational readiness incorporate some form of skills training to grow self- efficacy for people to become physically active and to maintain that behavior.

Of course, a person may remain in one stage or another for extended periods of time, or may experience relapse as a result of illness, lack of time, or other priorities. However, identifying the person’s stage and implementing strategies for dealing with the reasons for relapse can prove successful.

What keeps us from being physically active? Lack of time is the number one reason people don’t exercise at levels recommended for health enhancement. Individually adapted behavior change programs for physical activity promotion frequently incorporate strategies for helping people identify and overcome barriers. Barriers are the real or perceived factors that a person believes are in the way of being physically active or preventing increases in physical activity. Identifying barriers can help people prioritize physical activity. Once the barriers are identified, strategies can be developed to overcome them.

A short quiz that is useful in identifying barriers to physical activity is shown in form 13.1. Do any of these barriers apply to you? What strategies might be useful in overcoming the barriers to help you make physical activity a priority in your life?

SOCIAL SUPPORT FOR HEALTH BEHAVIOR CHANGE Related to, but distinct from, theories of behavior change is the concept of social support. Social support in public health refers to the degree to which people perceive that they are receiving assistance from their direct or indirect social network to overcome health challenges. Social support is thought to be key to promoting physical activity, either by being integrated into the existing health behavior theories and models reviewed earlier, or as a stand-alone strategy.

The concept of social support has been an important factor to understanding health behavior change and maintenance for years. It stems from observations that people with shared experiences and goals benefit from the support they receive from each other. This support could be in many forms: two people who want to become more physically active and begin to walk together in the mornings before work; a husband supported by his wife to restart a physical activity program; or a mother who supports her child to be physically active by enabling participation in a sport league after school. Each of these examples constitutes some form of social support for physical activity.

The three basic types of social support are perceived, received, and connected (Barrera 1986). Perceived support refers to the perception that one is adequately supported. For physical activity, an example would be a woman who knows she can count on church friends to walk with her when she needs company. Received support is more direct and measurable. It refers to the amount of direct support a person can count on for physical activity.

An example of this is a basketball team that must have five members to play. Each member counts on the others to be at the playground so the team can play. Finally, connected support refers to the degree to which a person is socially integrated. Social integration provides implicit social support as a result of the connections made through participation. Examples are clubs, communities and community events such as fun runs, the workplace, and family and friends. Connected support is thought to be helpful in physical activity promotion because of the experiences that can be shared through a social network.

Behavioral and social approaches for physical activity promotion increase physical activity either by enabling people with behavior change and management skills according to one of the health behavior theories or theoretical models in table 13.1, or by structuring the social environment so that it is conducive to physical activity behavior. Behavioral approaches give people skills to be physically active and to overcome barriers to implement those skills. Social approaches are one way to make it easier to use those skills.

Behavioral and social approaches increase physical activity participation as part of leisure, occupation, transportation, or at-home activities. Like informational approaches (discussed in chapter 11), behavioral and social approaches to increasing physical activity are based on the theory that when people are told to engage in specific health behaviors that are generally perceived as being good for them (e.g., improving health), they will change their behavior.

INDIVIDUALLY ADAPTED HEALTH BEHAVIOR CHANGE PROGRAMS Individually adapted behavior change programs integrate key components of health behavior theories and theoretical models to help people change and maintain physical activity behaviors. The evidence base behind these types of programs is strong, and these strategies work when implemented appropriately.

How physically active are your family members? Why are they active or inactive?

What kind of improvements can be expected in individually adapted behavior change programs? Substantial increases in physical activity behavior have been documented for these programs (pretest to posttest measures) in the Community Guide (USDHHS 2017). Increases in physical fitness ( O2max) and caloric expenditure have also been documented using these kinds of programs. Although the studies measure physical activity in a variety of ways and vary in length, such increases are impressive. For the physical activity outcomes, participation in such a program could be

expected to help the person achieve the 150-minutes-per-week goal recommended in the 2018 Physical Activity Guidelines for Americans (USDHHS 2018). Because they are not one-size-fits-all approaches, individually adapted behavior change strategies seem to work for both women and men. Moreover, they can be adapted to a variety of settings, including worksites, communities, schools, and possibly families.

To be most successful, individually adapted behavior change programs tailor the type and dose of intervention to the individual’s needs and preferences and take into account the local context and social environment (culture and social norms). As discussed earlier, this could be a stage-matched education curriculum for someone in the precontemplation or contemplation stage if the transtheoretical model is being used to guide the program development. Alternatively, another strategy could include a keen focus on how the person interacts with his or her environment to become more physically active, if social cognitive theory is guiding the program. The key point is that there are models and theories, but each type of strategy in individually adapted behavior change is guided by an emphasis on the needs of the individual and the individual’s needs for success.

When considering how individually adapted behavior change strategies could fit into a public health approach, it helps to identify specific examples. One such example of a promising individually adapted behavior change strategy, which could potentially be scaled up to reach a larger population, are mHealth strategies (medical and public health practice supported by mobile devices). Some researchers are currently working on developing and testing tailored smartphone applications (apps) grounded on solid behavior change theories, to match physical activity promotion strategies to the personality of each individual (King et al. 2016). Some people may respond to strategies that involve being social, working as part of a team, or competing with other teams. Others may prefer approaches based on the notion of self-management and self-regulation (e.g.,

using a fitness monitor to track daily activity levels). Finally, others may respond to strategies that optimize affect while being physically active. Affect refers to how being physically active makes you feel. For some, that amazing feeling of scoring a goal (compared to the intent to stay physically fit) is what truly motivates them to be physically active. Although this type of research is still in its early phases, the hope is that in the future, these type of strategies can be scaled up to reach many people around the world, and help everyone become and stay active in ways that work for them.

How do people change from being sedentary to being physically active? Although there is no one way for everyone, behavioral scientists rely on strategies that increase self-efficacy and move a person’s decision balance from more cons to more pros. Five strategies that are part of many individually adapted behavior change programs for physical activity promotion are shown in table 13.2.

Table 13.2   Behavioral Strategies Useful in Individually Adapted Behavior Change Programs to Increase Physical Activity

Strategy Intended consequence Example

Substitution Stay physically active when you may not even be thinking about being active.

Push back from a desk during work and take several two-minute walks during the day.

Social support (interpersonal)

Find a partner or partners to help you stay active.

Join a walking club or exercise with family members.

Self-reward Provide positive feedback to yourself for being physically active.

Set pedometer goals and reward yourself with a gift when short- and long-term goals are reached.

Commitment Encourage tangible commitments for yourself to being physically active.

Sign a self-contract; become a physical activity support to someone who is trying to become more active.

Reminders Use prompting tools to remind yourself and others about activity.

Place exercise shoes and equipment where they are visible (e.g., exercise machines in the middle of the house or apartment instead of hidden in a back room).

The art in this kind of work is finding the appropriate mix of strategies that will be most effective for the individual. Whereas some people need only simple reminders, others need several (or all) strategies to move into a physically active lifestyle.

SOCIOECOLOGICAL MODEL OF BEHAVIOR In addition to the traditional behavioral theories outlined in the previous sections of this chapter, it is worth paying special attention to more recent socioecological approaches to understanding health behaviors, including physical activity. While socioecological models of behavior are not as complex as full behavioral theories, they provide a conceptual framework and visual representation for understanding the multiple factors that influence physical activity, and therefore, potential solutions to encourage activity. Figure 13.2 presents an adapted socio-ecological model for physical activity. The basic principle of socioecological approaches for understanding health behaviors is that although the behavior (e.g., exercising every morning) occurs at the individual level, it is influenced by factors at multiple levels, which in turn interact with each other. There are many versions of the socioecological model of behavior available; some are very simple and some are very complex, but the principle of multiple levels of influence is the same across all.

Figure 13.2   Physical activity within different domains (leisure, transport, occupational, home) is influenced by different factors at each level. Adapted from Sallis et al. (2006).

For physical activity, the key levels of influence are the individual level, the interpersonal level, the social environment, the built environment, and the policy environment. At the individual level, one may ask: Is the person male or female? What is the person’s age? What is the education level of the person? All of these factors are known to influence an individual’s propensity for being physically active on a regular basis. The interpersonal level refers to the people that one interacts with regularly, such as family, friends, classmates, or coworkers. The concept of social support, which was previously described, generally falls under the interpersonal level. However, there may be social support strategies aimed at a higher level of influence: the social environment. The social environment differs from the interpersonal level because it refers to how society is organized or how it behaves as a whole—beyond the people that we personally know or interact with in our daily lives. Examples of social environment factors that can influence physical activity are the crime levels of a neighborhood, the average income of residents in an area, or the shared social values of a community. Some social support interventions target a whole neighborhood or community rather than specific individuals and their known social contacts (family and friends), and are therefore grounded in the social

environment level. The built and policy environments and their influence on population levels of physical activity are explained in more detail in chapter 14. Briefly, they refer to the physical features of urban or rural environments (e.g., roads, parks, public transit, pedestrian and bicycling infrastructure), and to the policies, laws, and regulations which can affect the opportunities for people to be active (e.g., speed limit regulations).

CASE STUDY

PROJECT ACTIVE The transtheoretical model—combined with aspects of social cognitive theory—was compared to a more traditional model of exercise promotion in one of the first long term studies to examine the role of individually adapted behavior change in increasing physical activity levels (Dunn et al. 1999). Project Active researchers recruited 235 sedentary women and men to participate in a two-year individually adapted behavior change program. These participants were between the ages of 35 and 60, were not obese, and were otherwise healthy (except for being sedentary).

The 235 participants were randomized into two groups. The structured exercise group received a standard exercise prescription encouraging them to become active at a certain intensity (based on their baseline tests) for 20 to 60 minutes on three to five days each week. These participants were also given complimentary access to a health club gymnasium for the first six months of the study. Finally, contact was maintained with them for the full 24 months through newsletters and periodic mailings.

Participants in the lifestyle exercise group received an individually adapted behavior change program that

used the transtheoretical model to match their stages of motivational readiness with appropriate behavioral intervention strategies and processes. They attended weekly meetings for the first four months of the program and then biweekly meetings for the next two months. These meetings focused on the cognitive and behavioral strategies thought to help people make positive, lasting changes. Each participant’s stage of motivational readiness was identified, and the strategies and processes used to increase knowledge and change behavior were matched to these stages. Topics covered in these meetings (among others) included how to set a goal and monitor progress, how to reinforce positive behavior, how to overcome barriers that get in the way of being physically active (problem solving), how to build social support, and how to prevent relapse.

The main outcome of interest in Project Active was physical activity (measured by estimated energy expenditure) in the two groups. Would those in the lifestyle group increase their physical activity as a result of the individually adapted behavior change program? How would any change in the lifestyle group compare to that in the structured exercise group?

The main findings from Project Active are illustrated in figure 13.3. People in both groups significantly increased their physical activity levels from baseline through 24 months. Perhaps most interesting, the

lifestyle group showed a statistically equivalent increase in energy expenditure from physical activity compared to the structured exercise group. Similar findings were seen for increases in aerobic fitness as well. These results showed that not only is an individually adapted behavior change program feasible for increasing physical activity among previously sedentary people, but it can also be a useful alternative for people who don’t prefer or don’t respond to more structured, traditional exercise prescription models. Can you think of some examples in which such a model may not be the best choice? Project Active confirmed the utility of behavior change programs for physical activity promotion.

Figure 13.3   Changes in energy expenditure (in kcal/kg per day) over 24 months due to physical activity in Project Active. Data from Dunn et al. (1999).

Socioecological models of behavior are useful when considering public health approaches for understanding and promoting physical activity. Addressing the problems occurring at the higher (or more distal to the individual) levels of the socioecological model allows us to reach entire populations. However, the effect of strategies targeting levels closer to the individual (inner circles) tend to be greater. This means that interpersonal or individual-level strategies may make a few people become much more active than previously,

while environmental strategies may make more people a little more active than previously. In an ideal scenario, a successful intervention would target all levels of the socioecological model; however, this is obviously a very difficult task. At the very least, when considering the use of individual or interpersonal strategies for physical activity promotion, one should be well aware of the characteristics of the social, built, and policy environment contexts where these interventions will take place. In this way, an interpersonal or individual strategy may help people overcome environmental barriers to be able to adopt and maintain an active lifestyle.

SOCIAL SUPPORT INTERVENTIONS IN COMMUNITY SETTINGS

Another recommended strategy for increasing physical activity via behavioral and social approaches is social support interventions in community settings. Social support is a broad concept, but it generally refers to any strategy for developing or strengthening the interpersonal connections or the social environment of people to encourage (or overcome barriers to) physical activity. Social support can be an important strategy in individually adapted behavior change programs, but the type of social support we refer to here is at the community level, rather than interpersonal level only. Therefore, this type of strategy operates in the social environment level of the socioecological model of physical activity (figure 13.2).

Community social support interventions focus on changing physical activity behavior by building, strengthening, and maintaining cohesive social networks in the community (i.e., beyond immediate family and friends) that provide supportive relationships for behavior change (e.g., a buddy system with neighbors, contracts with others to complete specified levels of physical activity, and joining local walking groups or other groups to provide friendship and support). Community social support interventions also often attempt to increase social capital, which broadly refers to the factors that contribute to cohesive and well-functioning societies. Some elements

of high social capital include a shared sense of community, living in areas where you feel you can trust your neighbors or ask for their help, being in a neighborhood where you can run into people and interact with them informally, and trusting your elected officials. Creating a heightened sense of community and trust, and fostering social interaction beyond an individual’s small social network, has been linked to healthier communities at large.

Studies of community-based social support programs to promote physical activity generally report the following findings (Kahn et al. 2002):

Social support interventions in community settings increase physical activity as measured in a variety of ways (e.g., blocks walked or flights of stairs climbed daily, frequency of attending exercise sessions, minutes spent in physical activity). Time spent in physical activity can be expected to increase by an average of 44% above baseline levels. Frequency (days per week) of physical activity can be expected to increase on average nearly 20%. More support (greater participation in social networks for physical activity) may be associated with a higher level of physical activity. The potential for a dose-response relationship between the two has not yet been demonstrated, however. Social support for physical activity promotion seems to be effective in a variety of settings (e.g., communities, worksites, universities), for both sexes, across the adult age range, and among people with various baseline physical activity levels (both sedentary people and those who were already active).

Does social interaction promote participation in regular physical activities?

In some recent studies with international settings, the findings have suggested that among certain populations and contexts, fostering social interaction may be as important or more important than promoting exercise or sport (i.e., physical activity to become healthier versus physical activity to have fun and spend time with others) (Salvo et al. 2017). Finding ways for people to be with each other in public, informal settings may be more effective than promoting individual-level behavior change with the focus on health, in cities in Brazil, Columbia, or Mexico. Understanding one’s social environment (social norm, culture, values) thus becomes extremely important when designing successful physical activity interventions based on social support.

As with any community-based work, developing community-based social support systems can be challenging. Whether it is a faith- based exercise program for one specific place of worship, a neighborhood walking club across several blocks, or a sport league in a parks and recreation department in a town or city, the most important first step in developing such programs is to know the target audience. The most well-intentioned program will never get off the

ground unless leaders and stakeholders are consulted and their ideas are considered prior to program development. Chapter 15 introduces the logic model and program evaluation strategies. A key first step is defining the problem through census data, health survey data, or other sources. And perhaps the most important step is to leverage existing networks and other sources of social support rather than trying to create new ones.

CASE STUDY

HEART AND SOUL PHYSICAL ACTIVITY PROGRAM Peterson and colleagues (2005) developed a unique physical activity program targeted at women in midlife (35 to 65 years of age) using churches as the target community and focusing on developing a social support system. Physical activity was promoted through the church-based support network. The goal of the project was to increase moderate-intensity physical activity among program participants compared to those in churches not receiving the program. Over a 12-week period, participants met for one hour each week and worked during this time to identify and develop ways to support each other to be more physically active. During the meetings, participants were asked to share their physical activity goals, barriers, and successes with other members and group leaders. Strategies for finding outside support (e.g., people to exercise with) were included. Participants in the control churches received an exercise brochure, information regarding physical activity recommendations, and several follow-up telephone calls during the 12-week session.

Although the study was fairly small, the participants in the social support group demonstrated a 63% increase in the minutes per week spent in physical activity that

was at least of moderate intensity. Those in the information-only control group churches also increased their minutes per week of moderate-intensity physical activity (by 43%), but not nearly as much as the social support group. The authors of this study concluded that this type of social support–based physical activity promotion showed some promise as a strategy to promote physical activity.

A final note: Although individually adapted behavior change programs and community-based social support systems have been scientifically shown to increase physical activity, other types of social and behavioral strategies have not. This may be due to lack of evidence (i.e., the strategy has not been rigorously tested) or because the strategy does not actually work. Of course, it is important to know what works, but it is also important to know what doesn’t work in physical activity promotion. Knowing the evidence base allows for more informed decisions about physical activity promotion programs. Clearly, programs for which there is evidence of effectiveness should take precedence.

According to the Community Guide (USDHHS 2017), social and behavioral approaches to physical activity promotion which lack evidence to recommend their implementation include college-based health, and classroom-based health education curricula for elementary, middle, and high school students. Additional behavioral approaches that the updated version of the Community Guide recommends to promote physical activity, but were not discussed extensively in this chapter, include enhanced school-based physical education, and family-based interventions.

LEADER PROFILE Melody Ding, PhD

Why and how did you get into the field of Physical Activity and Public Health? While I have always been passionate about exercise and sport, it was by accident that I got into this field of research. I was interested in how the environment influences human behavior, but when I was looking for a PhD advisor, I was fortunate to get an opportunity to work with Jim Sallis before I knew very much about physical activity research at all.

Did any one person have a major influence on your career? How? I have a few to name. I can definitely “blame” my parents for my pursuit of an academic career; they got me interested in science and physical activity at a young age and supported me all the way. Professor Mel Hovell from San Diego State University was a great influence on my career: He believed in me from the start by offering me an opportunity to study in the United States while I was still an undergraduate student in marine biology in China. He intrigued me with the world of behavioral science so much that I never wanted to leave. Professors Jim Sallis and Adrian Bauman, two brilliant researchers in physical activity, have had a substantial influence on the way I approach research. Mel, Jim, Adrian and others have remained my lifelong mentors, collaborators and friends. Finally, the field of physical activity is full of talented researchers, leaders, and thinkers who have inspired me.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice?

I enjoy the process of understanding physical activity by working with people outside of physical activity. For epidemiological research, I like considering physical activity as a core component of a constellation of health behaviors and understanding it within the context of the environments, circumstances, and lifestyles as a whole. For intervention and policy research, I am passionate about aligning the agenda of physical activity promotion with economic, social, and environmental cobenefits to advocate for investments in physical activity with ongoing societal dividends. Out of all research translation strategies, the one I use the most is communication. I have fond memories of speaking with peer-scientists, students, practitioners, policy makers, mass media, and the public, and I have truly enjoyed these experiences.

Why do you do what you do? For passion, impact, and friendship. I am passionate about physical activity and exercise in my personal life and would love to help more people around the world enjoy physical activity as much as I do. I strive for making changes in the real world, whether it is through generating evidence, informing policies and guidelines, teaching and education, or communicating with the public. Finally, I have made wonderful friends and comrades in the physical activity community and enjoy working together toward the same common goal.

What are two key issues that must be addressed by 2030? First, we need to drastically reduce our dependence on driving by means of reform in urban planning and transportation. We should reconsider how we travel and make active and public transportation the default choice.

Second, I would really like to see girls and women being as active as boys and men. We need to empower girls and women to take a leap forward, to embrace and enjoy physical activity, particularly in their leisure time. In many parts of the world, this involves removing structural and cultural barriers, creating safe environments, and providing social support. We cannot achieve gender equality without giving boys and girls, and men and women, equal opportunities to be active.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Behavioral and social approaches can improve readiness for individual and community behavior change. The behavior theories and theoretical models highlighted in table 13.1 and the socioecological model of physical activity in figure 13.2, as well as other theories and models, help explain why people are physically active or inactive, and also help to develop approaches for behavior change programs. Individually adapted health behavior change programs teach behavioral skills such as goal setting and self-monitoring of progress toward those goals, building social support for new behaviors, reinforcing behavior through self-reward and positive talk, structured problem solving to maintain behavior change, and preventing relapse into sedentary behavior. Individually adapted health behavior change programs are recommended to increase physical activity. Social support interventions focus on changing physical activity behavior through both interpersonal and social environment strategies, like building, strengthening, and maintaining social networks that provide supportive relationships for behavior change; and by improving the social norm of a community to become more supportive of active lifestyles by residents.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the

text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Ajzen I. 1991. The theory of planned behavior. Organizational

Behavior and Human Decision Processes 50: 179-211. Bandura A. 1986. Social Foundations of Thought and Action.

Englewood Cliffs, NJ: Prentice Hall. Barrera M. 1986. Distinctions between social support concepts,

measures, and models. American Journal of Community Psychology 14: 413-445.

Dunn AL, Marcus BH, Kampert JB, Garcia ME, Kohl HW III, Blair SN. 1999. Comparison of lifestyle and structured interventions to increase physical activity and cardio-respiratory fitness: A randomized trial. Journal of the American Medical Association 281: 327-334.

Dunton GF, Cousineau M, Reynolds KD. 2010. The intersection of public policy and health behavior theory in the physical activity arena. Journal of Physical Activity and Health 7 (Suppl 21): S91-S96.

Janz NK, Champion VL, Strecher VJ. 2002. The health belief model. In Glanz K, Lewis FM, Rimer BK, eds. Health Behavior and Health Education. San Francisco: Jossey-Bass, 45-66.

Kahn EB, Ramsey LT, Brownson RG, et al. 2002. The effectiveness of interventions to increase physical activity. American Journal of Preventive Medicine 22: 73-107.

King AC, Hekler EB, Grieco LA, Winter SJ, Sheats JL, Buman MP, Banerjee B, Robinson TN, Cirimele J. 2016. Effects of three motivationally targeted mobile device applications on initial physical activity and sedentary behavior change in midlife and older adults: A randomized trial. PLoS One 11 (6): e0156370.

Kohl HW III, Dunn AL, Marcus BH, Blair SN. 1998. A randomized trial of physical activity interventions. Medicine & Science in Sports & Exercise 30: 275-283.

Marcus BH, Banspach SW, Lefebvre RC, Rossi JS, Carleton RA, Abrams DB. 1992. Using the stages of change model to increase the adoption of physical activity among community participants. American Journal of Health Promotion 6: 424-429.

Peterson JA, Yates BC, Atwood JR, Hertzog M. 2005. Effects of a physical activity intervention for women. Western Journal of Nursing Research 27: 93-110.

Prochaska JO, DiClemente CC. 1983. Stages and processes of self-change of smoking: Toward an integrative model of change. Journal of Consulting Clinical Psychology 51: 390-395.

Ryan RM, Deci EL. 2000. Self-determination theory and the facilitation of intrinsic motivation, social development, and well- being. American Psychology 55: 68-78.

Sallis JF, Cervero RB, Ascher W, Henderson KA, Kraft MK, Kerr J. 2006. An ecological approach to creating active living communities. Annual Reviews of Public Health 27: 297-322.

Salvo D, Sarmiento OL, Reis RS, Hino AA, Bolivar MA, Lemoine PD, Gonçalves PB, Pratt M. 2017. Where Latin Americans are physically active, and why does it matter? Findings from the IPEN-adult study in Bogota, Colombia; Cuernavaca, Mexico; and Curitiba, Brazil. Preventive Medicine 103: S27-S33.

U.S. Department of Health and Human Services. 2017. What Works Fact Sheet: Increasing Physical Activity. Resource Summary (The Guide to Community Preventive Services). https://www.thecommunityguide.org/sites/default/files/assets/W hat-Works-Factsheet-PhysicalActivity.pdf. Accessed 25 January 2018.

U.S. Department of Health and Human Services. 2018. Physical Activity Guidelines for Americans, 2nd ed. Washington, DC: U.S. Department of Health and Human Services. www.health.gov/paguidelines/second- edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.1, 1.1.5, 1.4.1, 1.4.2, 2.1.3, 2.3.3, 3.1.3, 3.1.4, 3.3.1, 3.3.2, 3.3.3, 4.1.1, 4.1.2, 4.1.5, 4.2.5

CHAPTER 14 Environmental and Policy Approaches to Promoting Physical Activity

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  How aspects of the built environment can promote or hinder physical activity

»  How enhancing access to neighborhood destinations promotes physical activity

»  The role of urban design in physical activity promotion

»  The differences between micro-environmental (street- scale) and macro-environmental (community-scale) urban design, and how each can contribute to physical activity promotion

»  How the built environmental characteristics that may influence physical activity are measured

»  How physical activity is influenced by policies beyond the health sector, and how these policies are necessary to scale-up built environment strategies for physical activity promotion

OPENING QUESTIONS »  What is the physical environment? What is the built

environment? What is the natural environment?

»  Can the built environment influence the levels of physical activity of populations? If so, which aspects of the built environment contribute to physical activity? Which aspects hinder physical activity?

»  How can the local built environment be changed to increase opportunities for physical activity at the population level?

»  What strategies aid in the development and implementation of policies to promote active environments and active people?

What do you think of when you hear the term built environment? The apartment or home in which you live? The gym or fitness center downstairs? The buildings at your university? A hike and bike trail in the center of town? How does the built environment differ from the physical environment? Are they synonyms? Although these terms are often used interchangeably, they are not the same thing. The physical environment is a broad term encompassing all the physical aspects of the environment that surround us. This can include the city roads and lampposts, but also topographical aspects, such as

the steepness of a hill. There are two main types of physical environment features: those of the built environment and those of the natural environment. The built environment refers to any aspect of the environment, urban or rural, which has been created by people, such as sidewalks, roads, stoplights, crosswalks, buildings, and parks. In contrast, the natural environment refers to physical aspects of the environment which were not created or altered by people. As you may expect, natural environment features are more common in rural rather than urban settings; however, urban settings may also include natural environment features. Some protected national parks are located within city limits and were created by people (which would fall under the built environment category), but the actual natural resources have always been there. A river crossing a city is part of the natural environment; however, a paved walking trail alongside that river would be a built environment feature. The weather and wild animals are other aspects of the natural environment. Urban green spaces can be composed of a mix of built and natural environment features. In some parks all of the “natural elements,” such as plants, trees, and lawns, were put in place by people, making them built environment features. However, other green urban spaces, such as national parks may be naturally occurring, thus making them a natural environment feature.

We have known for centuries that health is related to the physical environment. In fact, at its origins, public health began by studying the ways in which the physical environment affects the health of populations. Where you live matters. Although this can be (and is) related to factors of the social environment, physical environment factors also play an incredible role in determining health. The quality of the water and air (natural environment), the type of housing (built environment), roads (built environment), and other environmental factors are critical to overall health, health care, and disease prevention. However, the physical environment is rarely independent of the social environment within it. As we learned in chapter 13, all levels of the socioecological model of behavior interact to influence

individual behavior. Within the realm of physical activity and public health, several elements of the physical environment— in particular some key elements of the built environment—have been studied extensively in recent decades. Substantial evidence links certain built environment structures to the levels of physical activity of urban populations. These structures can be positive (e.g., sidewalks or bicycle lanes), or negative (e.g., a high-speed six-lane road with no crosswalks) in their influence on physical activity.

As covered in chapter 13, strategies for individually adapted behavior change and enhancing social support can increase physical activity among individuals. Although these strategies may be sufficient for some people, public health is also interested in changes that affect population health. Thus, physical activity and public health should also focus on changes that may affect an entire group of people such as all the residents of a town, students enrolled in an urban school district, or the residents of an apartment complex.

How many parks are within one to two miles of your home? Are they sufficiently maintained to encourage regular use for physical activity? How could they be improved to support more physical activity?

Environmental and policy change initiatives to improve public health seek to augment the approaches focused on individuals. Actions at the environmental and policy levels directly affect organizations and physical structures rather than individuals, in an attempt to reach more people and achieve longer-term and more sustainable results. To maximize success, environmental and policy changes must involve many sectors of influence outside of health departments. For example, building a bicycle lane on a major street must involve the transportation department, the city government, and public safety experts.

POLICY INFLUENCES ON HEALTH

Changing or maintaining a behavior is difficult when external forces continue to work against the behavior. Effective health and health behavior policies include tobacco or sugar-sweetened beverage taxation, purchase age restrictions to reduce smoking and alcohol consumption, water supply fluoridation to reduce dental caries, speed limits and seat-belt laws to reduce motor vehicle fatalities, and breakaway bases in Little League Baseball to reduce musculoskeletal injuries in players. The field of public health differs from the medical and health care fields because it acts at the population level (rather than at the individual level) to prevent disease and disability. Can you think of other examples of public health policies, and in particular, those that may impact the physical activity levels of populations? When thinking of these examples, keep in mind that health-enhancing physical activity can occur within different domains (leisure-time, transportation, occupational, or home- based).

Major changes in public health rarely, if ever, depend solely on achieving behavior change in individuals. Policy initiatives, environmental initiatives, or both, usually facilitate individual behavior change. As shown in chapter 13, methods that target the higher levels of the socioecologic model (i.e., the built environment or policy level) usually reach many more people than those targeting the individual or interpersonal level. Environmental and policy approaches for physical activity promotion tend to focus on getting more people to become a little more active rather than getting a very small amount of individuals to become much more active. In this public health approach, small benefits for the majority of the population are preferred over large benefits for only a small group of individuals.

Environmental and policy approaches to physical activity promotion create or enhance opportunities, and support and prompt people living in a common area (e.g., a neighborhood, a zip code, a

county, a city, a state, or a country) to be more physically active. These approaches are often combined with informational outreach activities to enhance their effectiveness. Environmental and policy approaches may involve making changes to the built environment, making changes in organizational norms and regulations, or enacting legislation that improves health.

ACCESS Broadly defined, the term access refers to the ability to approach or use something. The concept of access is central to understanding the relationship of the built environment on physical activity, and understanding that the enhancement of the built environment is more conducive to active lifestyles. In physical activity and public health, creating or enhancing access to places for physical activity is an evidence-based strategy for increasing physical activity.

There are several types of access that may impact one’s ability to lead a healthy lifestyle. Geographic access refers to the features of the built environment in a person’s neighborhood. Two ways of assessing geographic access are with measures of availability (e.g., the number of nearby parks or recreation), or of accessibility (the ease of reaching a desired destination). To illustrate these examples, imagine that you have two neighborhood parks less than a mile from your home, and one of them is almost directly adjacent to your backyard. This means that you have high availability of parks in your home neighborhood. However, you live on a very long and winding cul-de-sac, and you must walk along a long road, without sidewalks in some places, for more than 40 minutes until you finally reach the park entrance. In this scenario, accessibility is quite low. Both availability and accessibility are important components of geographic access to places for physical activity. In addition, there are other dimensions of access beyond geographic access that may impact one’s ability to be physically activity, such as economic access. Now imagine that you finally reach the park behind your backyard; however, you want to use their tennis courts—which charge a fee.

For you, this fee may be restrictive and may deter you from being able to take advantage of this built environment neighborhood resource. The economic domain of access falls under the policy level of the socioecological model of behavior, and we will discuss it in further detail later in this chapter.

Most studies that have examined the issue of increased access for physical activity have focused on strategies for changing the built environment. Examples include converting an old rail bed to a hike and bike trail, building a new playground, or unlocking the school playground basketball court so that it can be used on weekends as public open space.

Although intuitive to some, the idea of creating or enhancing access to physical activity is not as straightforward as it seems. Simply clearing a new trail, cleaning up a park, building a new ball field, or providing more exercise equipment in a fitness center may not be enough. Most of the studies that have pointed to higher physical activity participation with increased access to places in which to be active have also included some form of programming, also referred to as place activation. Essentially, it does not appear to be enough to build or provide easier access to built environment resources that promote physical activity. Information and activities are necessary for people to learn about the existence of these new resources and to provide motivation to use them. For example, if a park has been cleaned up, a community campaign plus free exercise classes at the park on the weekends may get more people to take advantage of the newly improved resource.

In general, the physiological and behavioral results of studies examining increased access to places in which to be physically active support it as a recommended strategy (Kahn et al. 2002). Caloric expenditure among participants may be expected to increase an average of just over 8% above baseline. The percentage of people in a defined population exposed to increased access to physical activity might be expected to increase physical activity participation around 3%. Cardiorespiratory fitness (aerobic capacity)

should increase more than 5% on average. Some participants will increase much more, however, and others may not increase at all (or may actually decrease). Results of effectiveness (increased participation in physical activity) have been seen in various types of settings, in low-income communities, and in various racial or ethnic groups. Men and women seem to respond equally well to increasing access to places in which to be physically active.

CAUSE AND EFFECT? One of the major challenges facing researchers in the area of environmental and policy change for physical activity promotion is the lack of true experiments. A true experiment involves an experimenter randomly assigning a treatment (e.g., a pill) to one group and a control or placebo to another group, and measuring the subjects in each group before and after. More comprehensive experiments are blinded, and subjects do not know what pill they are receiving (treatment or placebo). It is very difficult, and certainly not practical, to randomly assign people to a neighborhood that has an optimal built environment for physical activity or to a neighborhood that doesn’t. People are free to live where they wish, so researchers must measure what occurs without experimentation. They cannot know whether characteristics of the neighborhood make people more active, or whether people who are already physically active or are looking for those characteristics are more likely to choose that neighborhood. This issue can confound studies looking to assess whether the cause (a neighborhood more conducive to physical activity) results in the effect (higher levels of physical activity participation). How would you design a study to tackle this problem?

Access is a general yet critical concept when studying the influence of built environment features on physical activity, and although the focus has been on specific places meant for recreational physical activity (e.g., parks, recreation centers, gyms),

the term access actually extends to any destination or place within a neighborhood or city. The accessibility of built environment features that are not thought of as being typical physical activity resources have also been found to be conducive to more physical activity. For example, access to public transit infrastructure or to shops and restaurants is associated with physical activity even though these are not places where people go to do exercise or sport. When these types of destinations are close to someone’s home, workplace, or school, they promote physical activity because people can actively travel to get there (i.e., by walking or bicycling, or in other words, by being physically active). Therefore, strategies to increase access to key destinations for physical activity promotion should not be limited to the places that people go to for exercise or sport. Increasing useful (public transit), fun, and vibrant (shops, restaurants) destinations within walking distance of people’s homes or workplaces is a way to promote transport-based physical activity. Similarly, it is important to understand the underlying social environment where you are trying to increase physical activity by increasing access to built environment resources. For example, in the United States, research has shown that increasing access to traditional places for recreational physical activity (e.g., parks and recreational centers) is an effective strategy for promoting physical activity (Kahn et al. 2002). In contrast, recent findings from Brazil, Colombia, and Mexico suggest that in Latin America, where social interaction is a much stronger cultural value than individual health and wellness, increasing access to places that facilitate socialization (e.g., public squares) may be a more effective strategy for physical activity promotion (Salvo et al. 2017).

URBAN DESIGN In the same way that access is not limited to destinations for recreational physical activity, adding new places for physical activity (e.g., building more parks, adding transit stops) is not usually sufficient for increasing access. There are several urban design

elements that are necessary for achieving appropriate and equitable access to optimal built environment resources. For the purposes of this text, urban design refers to the form, function, and outward appearance of the built environment in defined entities, such as neighborhoods, towns, cities, and communities. How practical is it to have new shops and restaurants within close distance if there are no sidewalks, bicycle lanes, or crosswalks in the neighborhood? In spite of the increased availability of nearby destinations, it is unlikely that someone would reach them via active travel if the urban design is not supportive of physical activity. Therefore, the concepts of access and urban design are codependent. Proper access to built environment resources that affect physical activity (e.g., parks, shops, transit) is hard to achieve without a good underlying urban design.

STREET-SCALE OR MICRO-ENVIRONMENTAL URBAN DESIGN Street-scale or micro-environmental urban design strategies to promote physical activity include changes to the built environment in small geographic areas, generally limited to a few blocks. Some examples of micro-environmental urban design elements which are relevant for physical activity include sidewalk availability, quality (e.g., width, flatness), and features (e.g., shade, benches); bicycle lane availability, quality, and features; crosswalks; pedestrian islands; posted speed limits and signage; and the availability of neighborhood traffic-calming devices. These approaches seek to make specific street segments (blocks) more safe and amenable to a variety of physical activity opportunities. Some specific strategies include marked crosswalks for pedestrians; traffic circles, stoplights, signs, and speed bumps for traffic-calming; the repair of broken windows and graffiti to increase safety and aesthetics; and improved lighting and landscaping.

Although the street and its features tends to be the focus of many micro-environmental urban design approaches, there are urban design elements beyond the street level that can be considered to be

on a micro-neighborhood environmental scale. Examples include the landscape design of a park, aesthetic features of a public square, and recreation center design.

USING CITIZEN SCIENCE TO PROMOTE MICRO- ENVIRONMENTAL URBAN DESIGN IMPROVEMENTS FOR PHYSICAL ACTIVITY One approach to improve the micro-environment which has yielded positive results in the design of small urban areas is the use of citizen science combined with community-based participatory research. Researchers have developed a process by which residents of a small (micro) area gather information about their local neighborhood environment which either hinders or promotes their ability to lead active lifestyles (i.e., they become “citizen scientists” as they collect data about their neighborhood). Then they discuss these findings with each other and prioritize themes, which are then presented to local stakeholders with the goal of negotiating some actions for improvements in the built environments (e.g., adding a cross walk), and social environments (e.g., implementing a neighborhood watch to prevent crime). This approach has been used in a variety of diverse micro- neighborhood environments around the world, such as the San Francisco Bay Area, Mexico, Colombia, Brazil, Chile, and Israel (King et al. 2016). In all settings, this process has resulted in small urban design changes that if scaled up, could contribute to helping populations become more physically active.

Studies examining street-scale or micro-environmental characteristics and their relation to physical activity have used a variety of outcome measures. Researchers have looked at increases in the number of walkers or bicyclists in a given area, the significance and change in prevalence of people who are physically active, and the number of users of a walking and jogging path. The

varied outcome measures make summarizing the effects of street- scale changes difficult. All things considered, a 35% average increase in physical activity might be anticipated with appropriate street-level changes (CDC 2011). The types of changes necessary clearly depend on the neighborhood that is targeted, and because no two are alike, the general recommendation can encompass many specific strategies.

CASE STUDY

BOGOTÁ, COLOMBIA Gomez and colleagues (2010) reported on efforts in the capital city of Bogotá, Colombia, to remake the city center and outlying areas to increase the mobility of citizens and recover public space to enhance the quality of life in the city. Many of these changes involved community-scale improvements in land use policies and urban design strategies. A large, modern mass transit system was created to reduce motor vehicle traffic and air pollution, green space and parks were created, and

bicycle paths (ciclorutas) were constructed to connect the parks. The remaking of Bogotá has been one of the most substantial urban redesign efforts ever undertaken.

The authors studied the role these changes may have had on physical activity participation. Using geographic information system (GIS) techniques (described in more detail later in this chapter), the study mapped the neighborhoods in which participants (men and women ages 18 to 65) lived, and the researchers analyzed the participants’ proximity to major community-level built or physical environment elements that may be related to physical activity participation. They considered neighborhood density, land use mix, the density of

parks, the completeness of ciclorutas, the proximity to transit stations, and the topographic slope of neighborhoods (Bogotá is situated on a plateau in a mountainous area).

Results suggested that active people were more than twice as likely to live in neighborhoods with the highest density of parks compared to inactive people, and those who lived closer to a new bus or rapid transit station were 27% more likely to be physically active than similar residents who lived farther away. Although causality is difficult to determine with this study design, it is clear that community-level built and physical environmental variables are associated with increased levels of physical activity.

Although micro-scale approaches can be scaled up to become community- or city-wide, they are most often initiated in small neighborhoods in which leaders are looking to improve residents’ livability and quality of life.

COMMUNITY-SCALE OR MACRO-ENVIRONMENTAL URBAN DESIGN Community-scale or macro-environmental urban design strategies for promoting physical activity involve changes and enhancements to the built environment of urban areas of several square miles (or kilometers) or larger, which are usually defined as being an administrative unit (zip code, neighborhood, school district, city, or county). These kinds of approaches strive to make entire communities more amenable to physical activity, whether that activity is transportation-related or exercise performed in discretionary time. Strategies at this level of influence include connecting transportation arteries; creating landscaping and lighting to enhance the aesthetics and perceived safety of the entire community; building a large-scale and interconnected network of sidewalks, bicycle lanes, and trails; and designing new mixed-use residential areas so that destinations such as workplaces, schools, and areas for leisure and recreation are within safe walking or bicycling distances.

CASE STUDY

DEVELOPMENT AND PROMOTION OF WALKING TRAILS Brownson and colleagues (2004) reported the results of an effort to increase access to walking trails in the state of Missouri in the United States. Adults 18 years of age and older were targeted. The study group was mostly women (75%), most had less than a high school education (60%), and 70% were Caucasian. Control groups were selected from similar communities in the neighboring states of Arkansas and Tennessee. The program was designed to increase the physical activity levels in rural communities, in part, by creating walking trails. Participants received eight individually tailored newsletters to promote interpersonal activities and social support, while advertising community-wide events such as walk-a-thons and walking clubs. The walking trails in the intervention were equipped with tracking systems to help people acquire individually tailored walking reports. The cost of trail development was approximately $3,000 (USD) per trail (six trails from 0.13 to 2.38 miles, or 0.3 to 3.8 kilometers, in length). Changes in the use of the walking trails and walking behaviors in general (minutes per week) were of particular interest.

After a one-year promotion effort in six communities, changes in walking trail use and walking behavior were observed in this study. However, these changes were limited to increases in trail use among those who already had been using the trails at the baseline or as they were built. In other words, there was an increase in use among people who had already reported using the trails. Although this is a positive result, the program seemed to miss affecting those who hadn’t used the trails prior to the study. Certain demographic subgroups showed increases in weekly walking participation, but a

change was not observed in the population as a whole. The authors concluded that this method of increasing access in rural communities should be used to understand how to design future studies in this area.

One important and unique macro-environmental urban design element is road connectivity. The concept of connectivity refers to the ease of getting from one place to another within a neighborhood using the city’s road network to walk or bike. If city thoroughfares follow a grid pattern, it is easy to use the street network (assuming sidewalks or bicycle lanes are available) to move around on foot or on bicycle; however, if intersections are very far from each other or there are quite a few dead-end streets or culs-de-sac, connectivity is considered to be sub-optimal. Another related construct for the macro-environment that has emerged in the past couple of decades is walkability. Walkability refers to the conduciveness of walking for transportation based on features of the built environment of an urban area. Many researchers have proposed different definitions of walkability, using scores or indices. Some of these scores are even used by real-estate companies to provide their clients with information about potential neighborhoods. High walkability scores or indices could indicate the best mix of built environment elements, and if optimized, could point to a neighborhood that is very easy to navigate on foot. Likewise, neighborhoods with low walkability scores are those with suboptimal conditions for transport-based walking. Most available walkability scores or indices include measures of connectivity, land-use mix, and residential density, which are three critical components for optimal urban design that promote walking for transportation in an area. Although this definition for walkability is valid in many parts of the world, it is not applicable in others (e.g., Mexico or China) (Salvo et al. 2014; Lu et al. 2017). Therefore, it is always important to consider the local context, including the social environment (social norms and cultural values),

when trying to promote walkable environments because these may look different in other parts of the world.

Studies examining community-scale changes for physical activity promotion have used a wide variety of outcome measures (Heath et al. 2006). Some have studied the absolute number of walking trips in a community over a given time period; others, the distance of those trips, minutes of walking per week, and number of pedestrians in a certain area. Although these outcomes are not entirely comparable, the general interpretation is that making the built environment more activity-friendly can improve levels of physical activity (regardless of how it is measured) by an average of more than 160%. Clearly, this is a major influence on physical activity habits in a community.

MEASURING THE BUILT ENVIRONMENT Measuring the built environment is a challenge. As covered in chapter 4, there are a variety of ways to assess physical activity behaviors and energy expenditure in individuals. Despite the limitations discussed there, we are able to reasonably and accurately assess physical activity in individuals, and reliably separate those who are most active from those who are inactive or somewhat active. We can reasonably assess and classify those who are meeting or exceeding physical activity guidelines (U.S. Department of Health and Human Services [USDHHS], Physical Activity Guidelines Advisory Committee [PAGAC] 2018). We can also identify the context and types of physical activity being done. Although there is much room for improvement, these methods have evolved and progressed over the years.

Because of the significance of the built environment in physical activity promotion, it must be measured, and measured well, if we are going to further our understanding in this important area. Unfortunately, this is a much less developed area of research than that of physical activity in individuals. Due to the relatively recent attention given to the built environment, this is to be expected; new methods and techniques are sure to continue to be developed.

Brownson and colleagues (2009) published a comprehensive review of tools and techniques that have been used to measure the built environment. They developed a categorization scheme that conveniently separates existing tools into three broad categories: self-reported measures of perceptions of the environment, direct observation techniques (audits), and secondary analysis techniques using existing datasets and geographic information systems (GIS).

Self-report techniques are used to query study participants regarding their perceptions of environmental supports of physical activity or barriers to physical activity. Most existing scientific evidence of an environmental effect on physical activity behaviors comes from studies relying on self-reports of perceptions of the environment. Such tools are typically administered in an interview (on the telephone or face-to-face), on the Internet, or via mail survey. These questionnaires typically assess perceived aspects of access; community-scale and street-scale characteristics such as traffic, aesthetics, urban design, and safety and crime; and the availability of local physical activity resources.

Self-report tools can be useful because most are relatively inexpensive to administer and can be used in large population studies; however, a respondent’s perceptions of the environment may or may not be consistent with reality. Respondents may over- or underestimate aspects of the environment based on their personal situation or health status. For example, someone who is rarely outside may not be aware of the environmental supports of physical activity and barriers to physical activity. Or less healthy people may not see the same things that their healthier neighbors see. The perception of crime is also a key issue. Studies suggest that perceptions of crime in neighborhoods do not match the reality of objective crime statistics. However, it is now known that both the perceptions as well as the reality of the neighborhood environment are important factors for understanding a person’s patterns of physical activity. Even if a neighborhood has sufficient built environment resources for physical activity, if a person perceives it

as not being supportive of an active lifestyle, it is likely that person won’t take advantage of their neighborhood’s objectives for activity- friendliness. For this reason, it is important, if possible, to combine self-report with objective measures of the built environment for a more comprehensive assessment.

WHAT IS A NEIGHBORHOOD? Studies relying on self-report often ask respondents to describe the physical activity resources in their neighborhoods. Unfortunately, there is not uniform agreement among scientists as to what exactly constitutes a neighborhood. A half-mile radius (approximately a ten- minute walk)? A one-mile radius (approximately a twenty- minute walk)? One’s zip code? Further, people’s perceptions of what constitutes their own neighborhoods also vary. To some, it is a few blocks around their home; to others, it extends to the first major avenue; and still others consider their apartment complex their neighborhood. Obviously, this variability injects substantial uncertainty into assessment techniques and can make comparisons among studies very difficult. What do you consider your neighborhood to be? Do you know what kinds of physical activity opportunities are available there?

To minimize the biases that can result from self-reports, scientists and planners often use more objective measures of assessment called audits. Audits are based on direct observation of the built environment of an area, and use inventories to quantify features of the community and street levels that can be observed, such as the existence and condition of sidewalks, noise and traffic levels, the presence of abandoned or unsafe buildings, and the cleanliness and usability of parks and park equipment. The results of these audits can be used for research, to change and improve the environment, or both.

Audit tools can be particularly useful when collecting data that are more standardized and not prone to respondent bias. Audits are usually more expensive to administer than self-report tools because of the personnel needed to collect and enter data for analysis and interpretation. Training personnel to collect audit data is crucial, as is reducing the variability of observations by standardizing terms and observation techniques. If a study is large, ongoing training and error checking of observers may also be required.

Geographic information systems (GIS) offer a third technique for assessing the environment. GIS are computational mapping methods that assist in analyzing geographic and social data (e.g., distances, landmarks, density, traffic, crime, resources, green space) by overlaying data in map format from multiple sources. Although the details of this technique are beyond the scope of this text, suffice it to say that GIS is an objective technique that allows multiple inputs from secondary data sources. With available computing power, GIS techniques have grown in popularity allowing desktop analyses of complicated geospatial datasets.

By using objectively derived datasets containing measures of the built environment, researchers and planners can use GIS to identify barriers to and supports of physical activity and relate the presence of those barriers and supports to physical activity levels in a community. GIS is most useful when large areas are under consideration and audits are not feasible because of costs and logistical difficulties.

Because GIS techniques rely on existing datasets that have been assembled for purposes other than research, the datasets may suffer from incompleteness or errors. These problems can present challenges when analysts attempt to relate the exposure data (e.g., neighborhood density) to the prevalence of physical activity in a geographically defined area. These challenges notwithstanding, GIS offers a tremendous resource that has yet to be fully explored for assessing aspects of the built environment as they may relate to physical activity behaviors. A recent study of 17 cities in 12 countries

of the world, the International Physical Activity Environment Network (IPEN) study, developed detailed protocols for generating standardized and comparable GIS measures of the built environment using secondary data from very diverse settings of the world (Kerr et al. 2013; Adams et al. 2014; Sallis et al. 2016).

How walkable is your neighborhood? Would you walk more if it was easier?

PHYSICAL ACTIVITY POLICY Physical activity policy can be defined as legislative or regulatory action, including formal and informal rules that are implied or explicit, that is instituted by an organization with the power to support or inhibit physical activity participation. Such organizations include governments at all levels, nongovernmental agencies (including employers, schools, and places of worship), and less defined groups such as neighborhood associations and social groups. Most, if not all, environmental approaches to physical activity promotion must result from some kind of policy change, so it is very hard to implement a meaningful small- or large-scale change to the built environment (e.g., adding a sidewalk to a road) without policy-level approval. The environmental approaches (as reviewed in this

chapter) then influence physical activity behavior, which in turn affects the health of individuals and populations.

According to Schmid and colleagues (2006), three broad classifications of policies can influence physical activity positively or negatively (i.e., encourage or discourage physical activity through environmental changes, supports, or barriers).

First, policies can include formal written codes, regulations, or court decisions that carry legal authority. One example is city codes that require a certain distance of building setback from a street to accommodate sidewalks and pedestrian traffic; another is a directive that all new roads must include sidewalks and bicycle lanes (e.g., Amsterdam in the Netherlands); and finally, a state legislative mandate for providing daily physical education to elementary school children is another example of a formal written regulation.

There are some policies which do not directly impact the built environment, but instead impact the ability and way in which people use the built environment. For example, a university campus may provide free public transit passes to all their faculty, staff, and students. This may promote more active travel (walking to and from transit stations) and inhibit sedentary travel (via car), improving economic access to a built environment resource (public transit infrastructure). So, even though it is not physically impacting the environment—it does affect how people interact with it.

INCREASING ACCESS TO PHYSICAL ACTIVITY AT A WORKSITE

Provide secure and covered parking for bicycles to

encourage bicycling to and from work.

Install employee shower facilities and changing

rooms.

Provide financial incentives for active commuting to

work or for using public transit (e.g., free transit

passes to encourage walking to and from transit

stops).

Create a culture of physical activity by encouraging

brief exercise breaks throughout the workday.

Provide on-site fitness facilities or buildings that

are conducive to physical activity, as well as easy

access to walking and running routes; distribute

walking maps.

Offer reduced-fee fitness or recreation center

memberships to employees and their families.

Encourage employees to participate in community-based

worksite exercise competitions or community-based

mass participation events.

Nonlegal, but accepted and written, standards are a second type of policy that may influence physical activity participation. The key difference between these types of policies and the legally binding ones is that these are not usually mandated. As a result of tradition or professional standards (e.g., urban planning, architecture, or engineering), these types of policies become standards of practice and can be used to encourage or impede physical activity participation.

Finally, unwritten social norms can also influence physical activity policy. More difficult to quantify, these are usually based in the culture of an organization or society and have the ability to influence physical activity in a variety of ways. Social groups in which most members value exercise and regularly participate may encourage new members to be physically active (i.e., social support). A worksite culture that encourages physical activity participation through informal walking groups is another example of unwritten social norms.

A stepped approach is necessary for understanding the effectiveness of physical activity policy. Further, physical activity

policy can occur at multiple levels, in multiple types of organizations, and in multiple geographic settings. Figure 14.1 illustrates this three- dimensional matrix.

Figure 14.1   Physical activity policy matrix. Adapted from Schmid et al. (2006).

On the left side of the matrix is the stepped approach. Beginning at the bottom, a policy is first identified as encouraging or inhibiting physical activity. Next, the determinants of that policy are identified. For example, why are certain city zoning codes in place that require culs-de-sac instead of grid-type connected streets? Next, the degree of policy implementation is of interest. How completely is the mandate being followed? Are there consequences for not following the policy? For example, does a school district conduct annual fitness testing of all students if a state law requires it, but suffers no consequences if it is not completed? Finally, what are the outcomes of the policy? Does it influence physical activity behavior? Does it impede it? Along the bottom of the three-dimensional policy matrix are the various sectors in which physical activity policies can be

implemented. Each policy type (legal, written or unwritten practices or standards, and unwritten norms) has roles in various sectors. For example, legal policies may address public spaces, transportation, and schools. Unwritten practices can be prominent in worksites and the health sector (e.g., physicians’ offices and hospitals). Social norms can be prominent in private spaces such as places of worship.

CHANGEABILITY? Clearly, macro-environmental level and policy changes to improve the built environment of cities cannot happen overnight, or even in the span of a few years. These structural types of changes require a long-term view and strong leadership given that physical activity and health benefits may not be seen for many years or decades. Because these are expensive propositions, community leaders must consider the financial impacts. Political challenges can slow such changes as well—not all stakeholders may be supportive of broad policy and community-level changes, but despite such difficulties, the long view is necessary. Perhaps the most relevant

question is, Can we afford to not make these changes for the sake of the health of our citizens? Some cities around the world, backed by their citizens and leaders, have begun to execute bold moves toward healthier, more active, and more equitable cities for all. Examples include Paris’s ambitious plan to remove all cars from the city center within the next few years, Amsterdam’s heavy investment on bicycling infrastructure, and Mexico City’s large-scale publicly operated bicycle-sharing program.

Finally, each policy type can operate at various levels of influence —local, state, regional, national, or international. Any cell in this four- by-six-by-five matrix can (theoretically) be isolated and examined for policies and policy determinants that may be used to affect the

environmental supports of or impediments to physical activity. Can you think of examples in one of the cells?

LAND USE POLICY Perhaps the most relevant factor of the built environment as it relates to physical activity is land use, which is directly affected by policies. Land use policies refer to the management, planning, and development of land in defined jurisdictions. Land use policies most frequently occur at the local level to advance the well-being of the communities that control the land. Zoning is another commonly used term that is synonymous with legislatively determined land use policy. Examples of land use strategies for physical activity include setting density targets (i.e., creating guidelines about the number of residents per square mile) for a neighborhood, green space mandates (e.g., preservation of undeveloped land) within town or village limits, and urban mixed-use developments that provide destinations within walkable distances to living spaces.

It is extremely difficult to implement access strategies aimed at providing new or different types of neighborhood destinations without a base land use policy which supports those changes. For example, it would be impossible to place a new park in a neighborhood if the current land use code doesn’t allow it. It would be similarly difficult to add a new public transit route, or more shops and restaurants, to an area designated as being exclusively residential (as compared to commercial or mixed-use designations).

Although no evidence-based formula for the perfect, or even optimal, set of land use policies exists that will maximize physical activity, many strategies have been shown to work in communities. Ongoing research will help us to identify specific approaches.

CASE STUDY

MUELLER The Mueller neighborhood in Austin, Texas, was built on the site of a municipal airport that dated back to the early years of aviation and was closed in 1999. As part of a redevelopment effort, over 800 acres were transformed into a new urbanist-inspired neighborhood. New urbanism is a neighborhood planning approach that creates sustainable communities by adhering to six principles: walkability (pedestrian-friendly street design), connectivity (interconnected street grid), a diverse and mixed-use built environment (shops, offices, and residences all in a geographically convenient area), mixed housing (a variety of housing choices), aesthetically pleasing and high-quality architecture, and public spaces in the neighborhood. Walking trails, parks, traffic-calming devices, sidewalks, bicycle lanes, and other strategies are hallmarks of the Mueller neighborhood design.

The development of Mueller offered a unique opportunity to study the effects of the street-scale design on physical activity participation. Although it was not possible to experimentally assign people to the neighborhood, a natural experiment was possible. Calise and colleagues (2012) surveyed newly arrived residents in Mueller about their physical activity habits before and after their move to the neighborhood. The hypothesis was that people who were less active in their previous neighborhoods would have higher reported physical activity levels in Mueller. The design of the neighborhood might be one explanation for any changes observed.

Key results of the study are shown in figure 14.2. After moving to Mueller, study participants reported an average of nearly 30 additional minutes of moderate- intensity and vigorous-intensity physical activity each week compared to when they lived in their previous neighborhoods. Interestingly, there was an increase in

reported recreational walking (about 45 additional minutes each week) after the move to Mueller, but there

was actually a decrease in reported walking outside the neighborhood (approximately 20 fewer minutes each week). The vast majority of the increase was in minutes per week of walking within Mueller. The authors concluded that the design characteristics of the neighborhood seemed to influence physical activity behaviors.

Figure 14.2   Changes in reported physical activity after moving to a neighborhood supportive of physical activity. Adapted from Calise et al. (2012).

LEADER PROFILE Nicolas Aguilar, PhD

Why and how did you get into the field of Physical Activity and Public Health? In my professional training, I realized that this field held the largest body of evidence in relation to the prevention of different diseases and their treatments. However, there was a huge gap in this specialty because the training of health professionals was very poor and very few public programs addressed the problem seriously. Therefore after finishing my physiotherapy degree in Chile and working in the public health system, I applied for a scholarship and moved to Australia to complete postgraduate studies in order to push for solutions to this issue in my country.

Did any one person have a major influence on your career? How? When I was completing studies in the Master of Clinical Exercise Physiology program, I was lucky enough to meet Wendy Brown. After sharing my expectations and future goals for my country and region, she invited me to undertake PhD studies under her supervision. I cannot be more grateful for her guidance and the time she invested in my professional training. Her leadership and ability to trust the decisions of her team was remarkable, and I admired how she simplified complicated problems and provided enriching feedback during that process. Despite being back in Chile, she has always been willing to help and believes that we can make a global change.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice?

A critical topic is capacity building (i.e., the process of developing knowledge and skills among individuals and organizations to carry out self-sustained public health research and practice in their own settings) in this area in Chile and Latin America; therefore, much of my effort is focused on this. Also, I am interested in increasing and developing evidence to identify population inequities in physical activity in an effort to reduce these gaps, while continuing to promote more active populations. The current efforts focus on identifying effective strategies and good practices to be able to adapt and apply them in the Latin American context. In addition, I actively participate in community and advocacy activities because the demands for change are great, but science (and funding) moves slower than these needs.

Why do you do what you do? I believe that we can change our world with the help of the sciences, but we need more communication and more effective ways to translate our findings. Physical activity is reflected in almost all things, especially in societal inequities. If we contribute to more equitable societies, we will have more active societies and vice versa. Many scientific articles conclude that their findings will be useful for public policies and will better inform decision makers. I believe that now is the time to actively participate in the design of public policies and to become part of the decision-making process. Our populations cannot keep waiting.

What are two key issues that must be addressed by 2030? We should report evidence that can be used by different sectors and be able to effect positive changes in environments that promote good quality of life, in terms of encouraging more active lives and more inclusive and accessible spaces.

Many countries are suffering from the consequences of global warming. Therefore, the inclusion of more active modes of transport and the protection of green spaces should be crucial government priorities. We need to move forward with these decisions before it is too late.

CO-BENEFITS OF ACTIVITY-PROMOTING ENVIRONMENTS AND POLICIES Often overlooked, but very relevant, are the effects that macro- environmental changes can have on factors outside of physical activity. In fact, strategies that are considered “physical activity policy and environmental interventions” are often motivated by entirely different factors than the promotion of physical activity and health. Some examples include plans to improve mobility and reduce congestion in large cities (e.g., implementation of modern mass transit systems, or large-scale bicycle sharing programs); strategies to improve social equity (e.g., Ciclovia in Latin America, known in the United States as “open streets,” where large portions of the road network are closed to traffic on Sundays for cyclists and pedestrians to use for recreation, providing access to other parts of town to non- car owners); strategies to mitigate pollution (e.g., no drive days); and many others.

Another example of the co-benefits of physical activity promotion is how various studies have reported higher rates of social interaction and social capital (i.e., trust and cohesiveness among a community) in neighborhoods that encourage physical activity. People in these neighborhoods have a greater sense of community, or belonging, when compared to those living in other neighborhoods. Some studies have even reported lower crime rates, which may be due to the implementation of physical activity promotion strategies.

Although these additional benefits to the implementation of physical activity promotion strategies (e.g., improving mobility and reducing congestion in large cities, or improving social equity) are not always guaranteed, they are helpful arguments that can support advocacy efforts for investing in more physical activity–friendly communities. This is especially true nowadays, given the global challenges that we are facing (e.g., economic instability, climate change), and the United Nation’s Sustainable Development Goals which highlight the need for more sustainable, equitable cities and

environments (UN SDGs, 2015). Knowing that in essence, a sustainable city is an activity-friendly city, we must seize the opportunity to simultaneously tackle the challenges of physical inactivity as well as those of urbanization, pollution, traffic, inequalities, and climate change, through joint solutions.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Environmental and policy approaches may involve changing the built environment; changing organizational norms and policies; or enacting laws or legislation that affect public health professionals, community organizations, legislators, departments of parks and recreation, transportation departments, planning commissions, and the media. Creating or enhancing access to key neighborhood destinations like parks, shops and restaurants, and public transit, combined with place activation efforts, involves the efforts of worksites, coalitions, agencies, and communities. Urban planners, architects, engineers, developers, and public health professionals use community-scale or macro- environmental urban design and land use policies and practices to change the physical environment of large urban areas to promote physical activity. Urban planners, architects, engineers, developers, and public health professionals use street-scale or micro-environmental urban design and land use policies and practices to change the physical environment of small geographic areas, generally limited to a few blocks, to promote physical activity. The three categories of measures of the built environment are self-reported perceptions, objective audits, and geographic information systems (GIS). Each has strengths and weaknesses, and all are evolving.

Understanding the determinants and outcomes related to policies that may support or inhibit environmental influences on physical activity is important. Policies can be formal (i.e., legal) or informal (i.e., based on tradition or social norms). Policies that support or impede physical activity can occur in multiple sectors and at multiple levels of influence. Understanding the intersection is important in determining how to change policies to support physical activity.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Adams MA, Frank LD, Schipperijn J, et al. 2014. International

variation in neighborhood walkability, transit, and recreation environments using geographic information systems: The IPEN adult study. International Journal of Health Geographics 13 (1): 43.

Brownson R, Baker EA, Boyd RL, Calto NM, Duggan K, Housemann RA, Kreuter MW, Mitchell T, Motton F, Pulley C, Schmid T, Walton D. 2004. A community-based approach to promoting walking in rural areas. American Journal of Preventive Medicine 27: 28-34.

Brownson R, Hoehner CM, Day K, Forsyth A, Sallis JF. 2009. Measuring the built environment for physical activity: State of

the science. American Journal of Preventive Medicine 36 (4 Suppl): S99-S123.

Calise TV, Dumith SC, Dejong W, Kohl HW III. 2012. The effect of a neighborhood built environment on physical activity behaviors. Journal of Physical Activity and Health 9 (8): 1089- 1097.

Centers for Disease Control and Prevention. (2011). Strategies to prevent obesity and other chronic diseases: The CDC guide to strategies to increase physical activity in the community. Atlanta: US Department of Health and Human Services: 3-4.

Gomez LF, Sarmiento OL, Parra DC, Schmid TL, Pratt M, Jacoby E, Neiman A, Cervero R, Mosquera J, Rutt C, Ardila M, Pinzon JD. 2010. Characteristics of the built environment associated with leisure-time physical activity among adults in Bogotá, Colombia: A multilevel study. Journal of Physical Activity and Health 7 (Suppl): S196-S203.

Heath GW, Brownson RC, Kruger J, Miles R, Powell K, Ramsey LT, and the Task Force on Community Preventive Services. 2006. The effectiveness of urban design and land use and transport policies and practices to increase physical activity: A systematic review. Journal of Physical Activity and Health 3 (Suppl): S55-S76.

Kahn EB, Ramsey LT, Brownson RG, et al. 2002. The effectiveness of interventions to increase physical activity. American Journal of Preventive Medicine 22: 73-107.

Kerr J, Sallis JF, Owen N, et al. 2013. Advancing science and policy through a coordinated international study of physical activity and built environments: IPEN adult methods. Journal of Physical Activity and Health 10 (4): 581-601.

King AC, Winter SJ, Sheats JL, Rosas LG, Buman MP, Salvo D, Rodriguez NM, Seguin RA, Moran M, Garber R, Broderick B, Zieff SG, Sarmiento OL, Gonzalez SA, Banchoff A, Rivera J. 2016. Leveraging citizen science and information technology

for population physical activity promotion. Translational Journal of the American College of Sports Medicine 1 (4): 30-44.

Lu Y, Xiao Y, Ye Y. 2017. Urban density, diversity and design: Is more always better for walking? A study from Hong Kong. Preventive Medicine 103: S99-S103.

Sallis JF, Cerin E, Conway TL, et al. 2016. Physical activity in relation to urban environments in 14 cities worldwide: A cross- sectional study. The Lancet 387 (10034): 2207-2217.

Salvo D, Reis RS, Stein AD, Rivera J, Martorell R, Pratt M. 2014. Characteristics of the built environment in relation to objectively measured physical activity among Mexican adults, 2011. Preventing Chronic Disease 11: E147.

Salvo D, Sarmiento OL, Reis RS, Hino AA, Bolivar MA, Lemoine PD, Gonçalves PB, Pratt M. 2017. Where Latin Americans are physically active, and why does it matter? Findings from the IPEN-adult study in Bogota, Colombia; Cuernavaca, Mexico; and Curitiba, Brazil. Preventive Medicine 103: S27-S33.

Schmid TL, Pratt M, Witmer L. 2006. A framework for physical activity policy research. Journal of Physical Activity and Health 3 (Suppl 1): S20-S29.

United Nations Department of Economic and Social Affairs, Division for Sustainable Development Goals. 2015. Sustainable Development Goals. https://sustainabledevelopment.un.org/sdgs. Accessed 25 January 2018.

U.S. Department of Health and Human Services, Physical Activity Guidelines Advisory Committee. 2018. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services. https://health.gov/paguidelines/second- edition/report/pdf/PAG_Advisory_Committee_Report.pdf.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.1, 1.1.2, 1.4.2, 2.1.3, 2.2.1, 2.2.2, 2.2.3, 2.4.6, 2.5.2, 3.7.1, 3.8.1, 3.8.2, 3.8.3, 4.1.1, 4.1.2, 4.5.3, 5.2.1

CHAPTER 15 Program and Policy Evaluation For Physical Activity and Public Health

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  The importance of program evaluation for physical activity promotion

»  The types of evaluation and when and how they should be used

»  The role logic models can play in program evaluation »  A six-step approach for effective evaluation

OPENING QUESTIONS »  Why should physical activity programs be evaluated? »  Does your program work? »  Does a school district policy that mandates daily physical

education classes for elementary school children result in uniform implementation across the district?

»  When should evaluation of a physical activity promotion project begin?

»  What constitutes success in physical activity programming?

Previous chapters highlighted effective evidence-based strategies for physical activity promotion. These strategies have been tested in research or practice settings and are designed for both individuals and communities. Interventions as fundamental as reminder signs at elevators help people choose to be physically active by taking the stairs instead. Projects such as improving sidewalks and neighborhood design also help people become physically active.

We know that these types of approaches, as well as specific programs, are effective because they have been evaluated. Evaluations allow us to make quantifiable conclusions about what a program has been able to change (or not) and by how much. This chapter covers fundamental aspects of evaluation and how it is critical for advancing our knowledge of what works in physical activity and public health.

When to begin the evaluation of a physical activity promotion project is a frequently asked question. Evaluation plans should be intertwined into all aspects of program planning from the program’s inception. If you wait until the project is underway to start thinking about evaluation, you’ve waited too long.

Published research offers many ideas for programs to increase physical activity. The translation from science to practice is an important aspect of public health, not only in physical activity, but in all fields. A new program at a senior center designed to reduce the risk of falls by promoting balance exercises, a walk-to-school program that encourages and rewards children and their families for getting to school without the means of a car, a worksite walking program that uses pedometers and gives employees breaks on the cost of their health insurance if they remain physically active, or a company-wide program providing all employees free public transit cards as well as paycheck bonuses for biking or walking to work are all examples of programs to promote physical activity.

Despite the contributions of science and its continuing evolution, the importance of measuring the effectiveness of a particular physical activity program cannot be overstated. Using the example of the senior center balance program, we would want to know the following: How many adults in the senior center attended the balance exercise classes? How frequently? Were the instructors trained according to protocols? Were the instructors effective in delivering the program? Were there any injuries? Was the program effective in reducing falls among participants? Was there a dose-response effect —that is, did people who participated more frequently in the program experience a lower risk for falls than infrequent participants did? Each of these questions (and more) addresses a critical aspect of program evaluation.

Program evaluation is important for many reasons. Obviously, you want to know whether your program has had the desired effect; therefore, quantification of the effects on participants is important. You have spent much effort putting the program together and delivering it—did it work the way you wanted? Did participants increase their physical activity? By how much? Was the increase enough to elicit changes in health status?

In addition to answering these fundamental questions, program evaluations also serve other important functions. For example, a

good program evaluation can be used to plan for resources— funding, personnel, and program materials—which can help to ensure overall success. Funders usually want a well-designed program evaluation that will reassure them that their investment helped participants. Evaluations can also identify program strengths and weaknesses—after all, some things will go right, some will go wrong, and some will be unexpected. If the program was successful, what aspects likely led to the success? What aspects need improvement? If the program is an ongoing one—say, a walk-to- school program—an evaluation can shed light on participation trends and suggest reasons for any shifts observed from year to year. For example, did the hiring of a new program coordinator have noticeable effects on participation? What did the new program coordinator do that resulted in the increase in participation? Did the timing of these new activities coincide with the observed increases in participation? Program evaluation, in short, is a set of strategies to help us understand what happened as a result of our efforts.

What policies in your community or neighborhood support or inhibit physical activity? How can they be changed?

Evaluation strategies can also be used in the larger context of public health policy development and implementation. For example, does a new municipal policy designed to increase bicycle use through the construction of bicycle lanes actually result in more bicycling among residents in that part of the city? If there are increases in bicycle lane use and bicycling, when did the increases occur? Are they limited to certain times of the day or days of the week? Are the increases transient, or can they be sustained over the course of months and years? Additionally, although this book focuses on physical activity and public health, depending on the program evaluated, there may be co-benefits of these programs worth measuring. In the previous bicycling example, for instance, we may be interested in measuring if there was also evidence of less motor vehicle traffic in the same area. In fact, some of the aspects often thought of as co-benefits of physical activity-promoting strategies or policies are actually the main reason why the programs were implemented by stakeholders in the first place. These reasons may include reducing congestion, improving air quality, and improving mobility equity, among many others. Another critical evaluation question to ask is if there were any unexpected outcomes or increases in adverse events (such as more bicycling-related injuries) as a result of the new policy. As with programs to increase individual physical activity levels, a good evaluation design can demonstrate the impact of policies aimed at groups of people, including those in cities, states, and larger geographic regions.

A Physical Activity Evaluation Framework proposed in 2002 by the U.S. Centers for Disease Control and Prevention (CDC) is still relevant and helpful in the development and follow-through of evaluation strategies for physical activity programming (USDHHS 2002). The framework has six crucial steps:

1. Engage stakeholders. 2. Describe and plan the program. 3. Define the evaluation.

4. Gather data. 5. Develop conclusions from the evaluation. 6. Communicate findings to ensure use.

Stakeholders are people and organizations with direct or indirect interests in the project. They can include funding agencies, target populations, policy leaders and decision makers, project staff, and the evaluation team. Stakeholders should be included in the program and its evaluation early in the process. Although the interest of each stakeholder group is unique (e.g., target populations have different interests than, say, decision makers), engaging all of them at multiple levels is important. This engagement process should involve communications strategies and briefings to ensure that all have an adequate understanding of the project. Evaluation efforts are usually a good meeting ground for project stakeholders because all have a common interest at some or all points along the formative, process, outcome, or cost-effectiveness framework for evaluation. Chapter 16 provides more information on developing and maintaining productive partnerships for public health programming.

WAYS TO MEASURE PROGRAM AND POLICY EFFECTIVENESS As soon as the program has been defined, thoughts should turn to defining the evaluation. This definition is an interactive process that can result in changes to the program plan. Because the program implementation plan and the evaluation plan inform each other, they should be addressed simultaneously. Asking questions about formative, process, outcome, and cost-effectiveness evaluations helps to clarify aspects of the program that may not have been part of the original idea. The logic model, discussed later, helps to create this interactive experience.

Figure 15.1   Four evaluation categories for a physical activity promotion program.

Although the evaluation questions one can ask about a physical activity program may seem endless, they can be conveniently categorized into four categories (see figure 15.1).

FORMATIVE EVALUATION Formative evaluation is the first level of a physical activity program evaluation. In formative evaluation, the fundamental questions focus on the needs, utility, and design features of a physical activity promotion program or policy and its individual components. Questions asked during the formative evaluation stage do not focus on the expected outcome (e.g., changes in physical activity behaviors), but rather on the overall design of the program. Formative evaluation questions for the senior balance exercise program discussed earlier could include the following: What is the extent of the problem of falling in the group? How frequently will participants be willing to come to the exercise classes? Will incentives be needed to increase participation? Is there a leader in the target population who can assist with outreach? What kind of equipment will be needed? How should instructors be trained? Clearly, this information can help the program manager or policy decision maker craft components that will have the best chance of hitting the intended target.

The primary information sources of data during formative evaluation are (1) expert opinion and previous work and (2) the target population of the program. Expert opinion, including that of the people implementing the program, comes from previous experience, similar work in other settings, published and unpublished examples, and other sources. The experiences of people who have done something similar can be invaluable to a program manager looking to build a physical activity promotion program. Often, these experiences are not published and are available only through networking with people who have similar intentions. A quick search of the Internet or published literature indexing services (such as MEDLINE), or both, can begin the journey down the road to gathering expert opinion.

Needs assessments provide the second source of data for formative evaluations. Needs assessments can be formal, standardized surveys or interviews, or more qualitative discussions with key people knowledgeable about effective strategies. However it is done, the general purpose of a needs assessment is to gather information from the target population (or one that is similar). For the municipal bicycle lane example, good needs assessment questions would be, How great is the need? Would people even be interested in using the bicycle lane? If not, why not? If so, what will keep riders using the bicycle lane over time? Will incentives to participate be helpful? How about disincentives to driving in the same area? What type of outreach should be used? In other words, what might work to fill the need?

Formative evaluation should be used throughout the program. Although it is necessary before the program starts to determine the best targets and strategies for implementation, it should not stop once the program begins. A well-designed formative evaluation provides feedback throughout program implementation so that changes and adjustments can be made. For example, interviews with participants and nonparticipants in a balance exercise class for seniors can help program planners understand the characteristics of

each group, why some continue to come, and why others dropped out or never came. They can then adjust the program accordingly.

PROCESS EVALUATION Unlike formative evaluation, process evaluation focuses on program or policy implementation. Of interest is how well the physical activity program or policy is operating and what can be done to improve those operations. Process evaluations help program managers assess the quality of program or policy delivery. They examine delivery strategies that appear to be successful and those that may not have worked as planned. Both are important not only for evaluating the program or policy, but also for informing future efforts.

Process evaluation should include the assessment of delivery alternatives. Program directors and policy decision makers can learn how best to deliver a program or implement a policy by testing their strategy against an alternative. For example, in a walk-to-school program, a pilot test could be designed to determine whether leader- supported walking groups (a parent volunteer leads children to school) result in more children walking to school than individual groups of children and their families. Such a systematic approach makes for a much stronger evaluation. Alternatives can be identified in the formative evaluation stage (discussed earlier), with input from potential program participants or experts. They can then be tested during a process evaluation.

Using the balance exercise class for seniors example, process evaluation questions may include the following: Are all exercise classes being offered as scheduled? Is instructor training and certification being offered consistently according to predetermined protocols? What is the attendance at the classes? How do these data compare to prestated goals? Are there trends in class attendance over the weeks and months that the program is being offered? Are other systems that have been put in place working as

intended? Why or why not? What program adaptations seem to affect attendance?

The information gleaned from these process evaluation questions can be useful for monitoring the implementation fidelity of the program or policy. Implementation fidelity refers to the extent to which the program or policy is being implemented as originally planned. For instance, do all senior balance exercise classes follow the preestablished curriculum? Or, do all balance exercise classes start on time? Additionally, process evaluation data can be used for understanding the program or policy outcome evaluation data (discussed next). For example, if outcome data for the balance exercise class show one or two sites that have reduced the risk of fall-related injuries among participants by 60 to 80%, the process evaluation data can be used to determine whether differences in implementation exist between the sites that are doing well and those that are not. If class attendance was routinely very high at the sites where falls have become less prevalent—and conversely, attendance was very low or intermittent at sites that have seen no change in the risk of falling among participants—it could be that the dose of physical activity was higher among those participants who are now at lower risk. Clearly, this process is not linear, but requires an understanding of evaluation outcomes on all levels.

OUTCOME EVALUATION Outcome evaluation, sometimes referred to as impact evaluation, focuses on cause and effect. Did the program or policy have the intended effect on the outcome of interest? For the purposes of physical activity promotion programs and policies, the outcome of interest is usually increasing levels of participation in overall physical activity, or in a specific physical activity (e.g., bicycling). Questions about the design and implementation of the program or policy have been answered in the formative and process evaluation stages. Now the question is, Has the program or policy increased physical activity behavior? Outcome evaluation seeks to answer this question while

also assessing, by process and formative evaluations, how the intended effects were reached (or not). Outcome evaluation metrics for physical activity promotion programs or policies could include minutes per week that the target population engaged in moderate- or vigorous-intensity physical activity, changes in their physical fitness levels, the percentage of the target population meeting physical activity guidelines, or the number of people bicycling for practical purposes at least once per week.

Because cause and effect is of central interest in outcome evaluation, changes in metrics such as these are often used as outcome (impact) measures. This, of course, assumes that a baseline assessment was done prior to the start of the program or implementation of the policy that will allow the calculation of change in the outcome of interest.

Outcomes of physical activity promotion programs and policies can be assessed using any of the measures discussed in chapter 4, with each having its strengths and weaknesses. In the walk-to- school example, the number of pedometer-measured steps that randomly selected students take per day, both before and after program implementation, may be an important outcome of interest.

EVALUATION QUESTIONS Physical activity evaluations come in all shapes and sizes. One characteristic of successful evaluations is that they have very clearly conceptualized evaluation

questions. This helps define the what, the how, and the who for the target population as well as for the program staff. Before starting any physical activity evaluation, program planners should work hard to state the questions as clearly as possible.

The underlying reasons for observing an outcome can be as important as measuring the outcome itself. To this end, physical

activity program and policy evaluations also focus on hypothesized upstream determinants as well. Upstream determinants are the known or hypothesized factors that cause a certain outcome (or do not cause a certain outcome) to a person or community involved in a program. For example, self-efficacy (i.e., in the context of this example, a person’s belief in his ability to become more physically active and sustain that behavior) is a likely mediator in participation in physical activity. If the balance exercise program for seniors shows an increase in participants’ self-efficacy and no such increase in those who did not participate, then the program evaluator might reasonably conclude that increases in participants’ beliefs that they can do the exercise program are one of the reasons physical activity increased in the group. A thorough outcome evaluation of a physical activity program not only measures the effects of the program or policy on physical activity behavior, but also suggests possible upstream determinants of that behavior. This gives program staff a better understanding of the mechanisms through which the program may be working.

COST-EFFECTIVENESS EVALUATION A final category of evaluation, and one that is often overlooked in public health evaluations, is related to the economics of the program or policy. The purpose of a cost-effectiveness evaluation is to assess not only the overall costs of delivery, but also how these costs compare with those of alternative program delivery options. Also of interest is how the costs of program or policy delivery and implementation compare to costs (real or estimated) of not delivering the program or policy.

In public health, the costs related to health issues (short-term as well as lifetime) must be balanced against program delivery costs. These health costs include the money spent to treat a disease, illness, or medical condition per person as well as indirect costs such as loss in productivity. Although a complete treatment of methods of cost-effectiveness evaluation is beyond the scope of this textbook,

the basic message is that this form of evaluation should not be overlooked. In the balance exercise program for seniors example, costs of implementation include staff salaries, physical resources, evaluation costs, and participation time (the cost of doing one thing at the expense of something else). These costs are then measured against any medical care expenditures (savings) that may be due to the balance exercise program (e.g., fewer emergency room visits, bone fractures, joint replacement surgeries).

Ding and colleagues (2016) published a study examining the global economic burden of physical inactivity. Using information on the known effects of physical inactivity increasing the risk of different health outcomes (e.g., cardiovascular disease, diabetes, cancer), as well as information on the cost of these conditions to health systems around the world each year, they estimated that physical inactivity cost health care systems $53.8 billion (international dollars) in 2013. Additionally, they estimated that deaths due to physical inactivity contribute to $13.7 billion in productivity losses each year, with physical inactivity being responsible for 13.4 million years lost due to disability (disability-adjusted life-years: DALYs).

Laine and colleagues (2014) conducted a systematic review of the evidence on the cost-effectiveness of different physical activity strategies. Cost-effectiveness analyses use information on physical activity program costs as well as gains in health outcomes to be expected from increases in physical activity (e.g., lower risks of heart disease, some cancers, and diabetes). The results of the synthesis of this evidence showed that the evidence-based physical activity promotion strategies highlighted in chapters 11 through 14 of this text provided a good value for the money needed to implement them. In their review, Laine and colleagues found that among the most cost-effective strategies to promote physical activity were the expansion of community trails and paths ($0.006 per MET-hour gained [2012 USD]), the use of pedometers as a behavioral strategy to increase walking ($0.014 per MET-hour gained [2012 USD]), and school-based physical activity promotion programs ($0.056 per MET-

hour gained [2012 USD]). Although there is a wide range of costs and benefits for evidence-based and effective physical activity programs, for many of them, the health gains associated with increased physical activity far outweighed the costs.

HOW MUCH SHOULD AN EVALUATION COST? Program planners frequently neglect to budget for an adequate evaluation, particularly at the proposal stage. Even the best, most innovative physical activity promotion program will be unable to demonstrate effectiveness without an adequate evaluation budget. How much money is needed? Although there are no clearly developed guidelines, a good rule of thumb is to dedicate 10% of an overall project budget to evaluation activities (personnel, data collection, analysis, and reporting).

Of the four types of evaluation covered in this chapter, the cost- effectiveness evaluation often has the most influence on policy makers and leaders. If a physical activity promotion program or policy is shown to actually save money by reducing the burden (and costs) of disease and disability, leaders and policy makers often consider it a wise investment.

LOGIC MODELS FOR PHYSICAL ACTIVITY PROMOTION AND POLICIES The first steps of evaluation are interlaced with the overall program development and delivery. The who, what, where, when, why, and how questions are answered in this phase. Who is your target audience? What do you want the target audience to do? When do you want them to do it? How will it get done? Who is in charge of what aspects? In these early steps, the logic model for evaluation should be developed and refined because it will assist in evaluation as well as overall program development.

Program evaluation in physical activity and public health can get very complicated. From the initial framing of the evaluation questions and understanding antecedents and outcome relationships, program managers must keep track of many inputs, outputs, and the relationships between them. Logic models provide the hub around which all evaluation activities can be linked, and describe and define the interrelationships of resources, the target population, short-term and long-term effects, and the ultimate desired outcomes.

A logic model is fundamentally a graphic or narrative description of the processes and interrelationships that can lead to a result (cause and effect). The most fundamental use of a logic model is to ensure consistent communication among project personnel and stakeholders. A well-constructed logic model helps everyone involved or interested in a project work from a consistent set of terminology and gain a common understanding of the intended and unintended (the expected and unexpected) consequences of a program or policy. Finally, the logic model helps to drive program and policy evaluations in a timely manner when coupled with a project timeline. A schematic of a generic logic model for program and policy evaluation is found in figure 15.2.

Figure 15.2   Schematic of a logic model for physical activity program evaluation.

The interrelationships of interest actually begin in the lower right- hand corner of the model in the area labeled “Ultimate goal.” In fact, it is sometimes easier to build a logic model from right to left rather than from the more natural left to right. The ultimate goal of most physical activity promotion programs and policies—although not often measured in the context of specific programs or policies—is improved health for the participants. This could be determined by examining risk and rates of disease or mortality. Although such outcomes are central to the reasons for promoting physical activity, waiting for some of them to happen, or not to happen, can take years and is beyond the scope of measurement for many programs and policies, particularly those interested in more short-term behavior changes. Although ultimate goals are beyond the horizon for many physical activity promotion programs, program managers should nonetheless keep them in mind because they are a reminder of why the programs and policies exist.

Of note, each of the four ways to evaluate a physical activity program or policy (formative, process, outcome, and cost- effectiveness) detailed in the preceding section is part of the evaluation framework and is overlaid onto the logic model schematic.

Outcomes, which are clearly of interest in a physical activity promotion program, are presented schematically in figure 15.2 immediately above (and before) the ultimate goal. Outcomes can be conceptualized in terms of time. What can be expected (and should be measured) shortly after program implementation (short-term outcomes)? What can be expected after short-term outcomes (mid- term and long-term)? Short-term outcomes of a physical activity promotion program could include improvements in knowledge, skills, initial program participation, and physical activity behaviors. Mid-term outcomes could include ongoing program participation and costs associated with continuing program delivery. Long-term outcomes could include ongoing participation in physical activity after the program has ended, changes in physical activity participation among the family members of program participants, direct and indirect

costs, and possibly policy changes to maintain the program. As is shown in figure 15.2, outcome, cost, and some process evaluation activities can occur in each of these outcome categories.

Moving to the left in figure 15.2, the logic model is also used to define the processes of both the program and the target population(s) (audience). The audience for a program should be fairly well defined, but could also include subgroups such as family members or neighbors not directly participating in the program. Activities of the program should be defined as processes as well. These include training sessions for the staff members who will actually deliver the program and specific activities (e.g., exercise classes, educational activities or products, special events such as mass participation events, stakeholder meetings, communications activities). Formative and process evaluation strategies also occur in the processes phase.

Why does changing public policy about physical activity promotion require many steps over time?

Next in figure 15.2 (to the left) is resources. A thorough understanding of resources (and how to acquire and manage them) is critical to include in a program evaluation. Without resources, programs don’t exist. Resources can certainly include funding, but they also include paid personnel, volunteers, the time needed from all staff, partnerships (e.g., other stakeholders in the program), and the physical venue (e.g., places for the exercise classes). Items in the “Resources” box in figure 15.2 are limited to those that a program evaluation staff can control or measure. Formative

evaluation is used to assess and define the resources needed for a program.

The formative evaluation should involve defining and clarifying the need for the program before initiating it. This process could include analyzing health data (linking to the ultimate goal discussed earlier), gathering input and determining demand from stakeholders in the target population (e.g., bicyclists in the case of constructing bicycle lanes), or conducting surveys. This needs assessment is used to justify program development (and consequently, evaluation). Needs assessments can be standardized (e.g., questionnaires) or more interactive (e.g., expert opinion). Physical activity programs should not be developed or delivered without a clear understanding of their necessity and the ultimate goal.

The final consideration when developing a physical activity program is uncontrollable external factors. Factors beyond the control of program staff and participants can negatively affect any step along the logic model. Although program staff may not be able to control outside influences (e.g., competing programs or changes in the weather that may influence physical activity participation), it is helpful to recognize these possibilities and plan accordingly to minimize their effects.

Each logic model is unique because each program is unique, as are their evaluation processes and needs. The generic framework in figure 15.2 should be modified according to the needs of the specific program. Because logic models can get very complex, program managers should start with a basic structure and then continue to develop it as program planning and a work plan emerge.

A real-life example of a logic model for a physical activity promotion program is shown in figure 15.3. The Walk a Hound, Lose a Pound project seeks to increase physical activity participation by promoting dog walking in a community (USDHHS 2010). Can you identify unique aspects of this logic model that would not show up in others?

EVALUATION DESIGNS The success of a physical activity program or policy often rests largely on its evaluation design. This generally falls into two broad categories: experimental and observational. Experimental evaluation studies, considered to be the gold standard, are characterized by one important aspect that observational studies do not have: randomization. With randomization, people, groups of people, or places are randomly assigned to the program treatment or to a control (i.e., not receiving the treatment). Randomization has many benefits, but its most important advantage is that it distributes any unknown errors randomly among the treatment and control groups. This is significant because unknown errors can affect the results of a program evaluation, thereby affecting the inferences drawn from that evaluation.

Unfortunately, randomization is rarely possible in the real world of physical activity and public health. People must live their lives, and assigning people to a no-physical-activity control group is not entirely ethical, particularly because we know the health benefits of physical activity. Experimental evaluation studies for physical activity and public health promotion programs have proven most useful when the programs were short and focused on specific (smaller) groups of people.

When experimentation is not possible or impractical because of costs or other barriers, observational evaluation studies are a useful alternative. Often referred to as quasi-experimental designs, these programs differ from experimental ones in that they are not randomized. Groups are divided into treatment and control based on convenience, receptivity, targeting, and other factors. Control participants or populations (i.e., those not receiving the program) are selected based on their comparability to the treatment group on factors such as age, sex, race or ethnicity, and baseline physical activity participation. What the randomization procedure accomplishes in experimental studies—spreading the unknown error equally among groups—is accomplished by statistical techniques in

observational studies. These techniques minimize sources of unknown variability during data analysis.

Figure 15.3   The Walk a Hound, Lose a Pound logic model.

DOSE-RESPONSE ANALYSIS Advances in physical activity research have made the one- treatment, one-control design somewhat antiquated. More often, a key question is, Does the response to a physical activity program or policy (i.e., participation in physical activity) depend on the dose of the program or policy to which a person is exposed? Three or more

evaluation groups are needed to conduct a dose-response analysis. These can be conceptualized in a variety of ways, but most often they consist of high-dose, medium- dose, and no-dose groups. If the results suggest that the outcomes correlate with the dose received, cause and effect is easier to argue.

Frequently, a clearly delineated control group is unattainable in public health practice. For example, if a policy mandates daily physical education classes for elementary school students in an entire school district, no control group would be available. In this case, a delayed implementation design could be used. In such a design, all children would receive the benefit of increasing physical activity through quality physical education classes, but in some schools, the policy would be delayed. This would give the evaluators an opportunity to estimate program effects without withholding the program or having an “untouched” control group.

DATA COLLECTION AND ANALYSIS Without data, there is no evaluation, and therefore no facts, only opinions. Each question at each phase in a physical activity program evaluation must have data sources to assess the effect of the program. These data sources can be quantitative (e.g., questionnaires, attendance sheets, delivery logs, production schedules, training manuals) or qualitative (e.g., interviews). The data sources used in an evaluation must help answer specific questions. For example, if a process evaluation question for the balance exercise class for seniors involves the fidelity of class delivery (i.e., whether the balance exercise class was delivered according to schedule each week), a data system must be in place to capture that information. If changes in balance indicators and a reduction in falls are desired mid-term and long-term outcomes of the project, data systems must be able to capture that information.

Data system development and data collection can be thought of as a process evaluation question as well.

Conclusions from the evaluation are drawn from the analysis and interpretation of the data. Data analyses should be closely tied to the questions asked in the evaluation and represented in the logic model. For example, if changes in class participation are of interest, then preprogram and postprogram data are needed. Changes in these data can then be interpreted as due to program participation.

Changes in outcomes of interest that are due to a physical activity program or policy can be measured in all participants or in a smaller, randomly selected group that (hopefully) is representative of the full group. If the program is small enough and the evaluation budget is large enough, all participants can be measured before and after the program (and sometimes along the way) for outcome evaluation. Using our balance classes for seniors example, physical activity behaviors and incidence of falls could conceivably be measured in all participants over the course of the program. Larger physical activity programs and policies that affect large groups of people or entire communities require carefully designed sampling techniques that identify a relevant subgroup of participants. Any changes (or lack thereof) observed in these subgroups are meant to be representative of the situation in the larger target population.

Conclusions from data analyses are also closely tied to the evaluation design. Control groups are especially important when evaluating program effects. A change in those who participated in the program cannot be assumed to be the result of a physical activity program without measuring similar outcomes in the control or comparison group. For example, in evaluating the impact of new bicycle lane infrastructure in a city, if we only measured bicycling among people that live in that part of town, and found that bicycling went down at a certain point in time, we can’t necessarily conclude that the policy didn’t work. A control group (people living in a different part of town with no exposure to the new bike lanes), might have shown a similar pattern of decline in overall outdoor activity at a

given point in time. This might be due to many reasons impacting both groups, such as a city-wide crime wave making people less prone to walk or bike, or an unusually long streak of rainy weather in the region. The principle of using a control group and measuring changes in the outcome, as well as process indicators, in both groups, applies to both quantitative and qualitative data. Having a comparable control group that is very similar to the intervention group (the group receiving the program/policy), provides stronger rigor to the findings of a program evaluation. When a control group is included, analyses of results are much less ambiguous and much more definitive.

CASE STUDY

WEST VIRGINIA WALKS Reger-Nash and colleagues (2008) published an evaluation of a community-based physical activity promotion program called West Virginia Walks. This program was a follow-up to an earlier social marketing program designed to increase walking behavior among residents in a 12-county area of north-central West Virginia. At the time, more than 360,000 people resided in the target area. The program goal was to increase walking behavior among 40- to 65-year-old residents who were insufficiently physically active at the start of the program. The program was a community-wide approach, using mass media outreach (see chapter 11).

The evaluation design for West Virginia Walks focused on identifying any behavioral outcome changes in physical activity (specifically, reported walking behaviors) that could be attributed to the program. The treatment group consisted of people living in the target area. The control group consisted of residents of

another county in West Virginia who were not exposed to the program or the mass media outreach from the program. Also of interest were process evaluation markers—in this case, self-enrollment statistics, use of a web-based tracking tool to help people log their behaviors, and most important, media attention to the program. Media attention was an important process evaluation measure because the program relied heavily on mass media (i.e., television, radio, and print) for promotion and awareness. Other process evaluation measures included documentation of any municipal-level changes in policies or in the environment designed to support physical activity that could be tied to the program.

Evaluation results showed several positive findings. First, there was very high recognition of the West Virginia Walks program in the treatment area. Residents in the area targeted by the program were significantly more likely to recognize and know about the program than were residents in the control area. This process evaluation indicator suggested that the program reached its intended audience.

Short-term changes in walking behavior were used as the primary outcome evaluation indicator. Households in the program area and in the control area were randomly selected prior to the campaign. Walking and other physical activity behaviors of residents in these randomly selected households were assessed by telephone interview prior to the start of the campaign and following its completion. Differences in participation rates between the two groups were interpreted as being due to the campaign.

After the eight-week community-wide campaign ended, the outcome evaluation results showed that 12% of the target population—who were previously insufficiently active—became active at least 30 minutes per day on five or more days each week. This change translated to an average additional 30 minutes each week of total walking time in the targeted community. Similar changes were not observed in the control community. These results showed that the West Virginia Walks program increased physical activity throughout a large geographic region.

IMPORTANCE OF ASSESSING CO-BENEFITS AS PART OF A PHYSICAL ACTIVITY PROGRAM EVALUATION Oftentimes, physical activity promotion strategies, programs, or policies have other benefits beyond the increase in participation in physical activity among the target population. For example, a free YMCA program providing sport activities for youth in disadvantaged neighborhoods may not only help improve the health of its participants through increased levels of physical activity. The co-benefits of such a program may include better grades, increased social cohesion among youth in the area, and lower propensity to engage in risky health and social behaviors (e.g., decreased likelihood of joining gangs, smoking cigarettes, or drinking alcohol). Identifying and evaluating the impact of the physical activity program or policy on these co-benefits may prove beneficial when communicating the findings to key stakeholders who are considering scaling up these programs. Oftentimes the priorities of stakeholders are not necessarily centered around physical activity promotion, so finding the added benefits of these programs, and building them into the evaluation plan, is both important and strategic.

Similarly, there may be programs or policies for which the main goal is not to promote physical activity. For example, the expansion of a bus or light-rail transit system in a city usually revolves around the need to improve mobility and reduce congestion. For the creators and implementers of these programs or policies, physical activity may simply be the co-benefit. Therefore, it is important to work with partners outside of the physical activity and public health realms to make sure that physical activity indicators are being properly included in the evaluation of these types of programs or policies.

An important consideration when interpreting evaluation findings is how the results compare with those of similar programs. The similarities could be in the target population, the type of program, the

type of outcomes assessed, other variables, or some combination of these. Consulting someone who has expertise and interest in data analysis and statistics (such as a local partner in a college or university) can be invaluable.

DISSEMINATING RESULTS Evaluation plans and data analyses are useless unless the findings are communicated in an effective manner to the right audience. Communication targets for evaluation results should include immediate stakeholders, with the first priority being those who provided the funding. Often overlooked, but equally important, is the communication of key findings to program participants. As key stakeholders in a physical activity promotion program, participants (or targets) should be informed all along the way, and receive a full briefing on the outcomes of the project. Although many may not have an interest in the overall results, some will. Such communications are critical to ensure future support, if necessary.

The format or channel of communications will differ depending on the needs of the audiences. For example, the funding agency will need a detailed final report with all associated materials and methods, including the formative, process, outcome, and cost- effectiveness evaluation results. Project staff will also need such detail. Program participants and partners may be satisfied with top- level summary findings, and other interested parties may be satisfied with a fact sheet (printed or posted to a website), which summarizes the project and key findings. Policy makers will likely be interested only in the key recommendations and the cost-effectiveness results. The important message here is to not underestimate the importance of communicating the results of an evaluation, and to “speak the language” best suited for the intended audience. There is no use in only publishing the results of an innovative program evaluation in a prestigious scientific journal, which is only read by other researchers, and not communicating the key takeaways to policy makers. Policy makers are the ones that can use these results to improve the

quality and reach of their programs, and help scale effective programs and policies to reach more people. On the other hand, researchers can learn better ways of doing physical activity program evaluation from each other. Identifying the key target audiences, their preferred channels of communication (e.g., scientific journals, policy briefs, infographics, YouTube videos), and disseminating the results accordingly to all, is a critical aspect of good program evaluation.

LEADER PROFILE Anna Porter, PhD

Why and how did you get into the field of Physical Activity and Public Health? During my Master’s of Public Health studies I stumbled into bicycle commuting as an alternative to paying and fighting for parking. Bicycling quickly turned into an obsession for me, and right around the time of my graduation some friends and I decided to start a bicycle cooperative (a nonprofit organization devoted to making bicycling accessible and affordable to all people). I worked in clinical research for a number of years while riding bikes and running the bike co-op, but eventually started thinking that I would like to go back to school to pursue research in my own areas of interest. I had come to the realization over the years that cities throughout the United States, and particularly in the southeast, were

seriously lacking infrastructure that would allow for safe and accessible bicycling, particularly for our most vulnerable populations. Once I explored the research that was being done at the time on bicycling and the built environment (not a whole lot as it turns out), I recognized that this was an area where I could make an impact.

Did any one person have a major influence on your career? How? It would be hard to identify just one person, but I know I would not be where I am today without the support of my mentors Dr. Bill Kohl and Dr. Kelly Evenson. They have both been encouraging and supportive of my “niche” interests, and have pushed me to go above and beyond what I thought was possible for myself.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? My interests primarily revolve around bicycling—what influences people to bicycle and what outcomes are associated with bicycling. I conduct research on how the built environment, as well as other community- and policy- level factors, supports or hinders bicycling in diverse environments and populations. I also study how specific types of physical activity such as bicycling are associated with morbidity and mortality outcomes. Around all of this is another focus of mine, which is looking at bicycling apart from the more general term of “active transportation,” which lumps bicycling and walking together. To explain further, I am looking at bicycling domains— recreation and transportation—as independent types of activities with their own motivations and influences.

Why do you do what you do? I think bicycles are awesome! They are a great means of transportation, and provide innumerable benefits to both the individual and society in terms of health and well- being, and are just fun to ride. I truly believe that if we can get more people off their couches and out of their cars, and onto bicycles, the world will be a better place. The biggest barriers for this, however, are safety and

accessibility. If my research can progress the narrative for communities to consider the needs of bicyclists when designing streets, or for a workplace to consider how to support bicycle commuting, then it’s a job well done.

What are two key issues that must be addressed by 2030? One issue I think needs to be addressed is the necessity for more research on how environments can be designed to support physical activity—and bicycling for transportation in particular—in rural communities. There is unfortunately very little research on what types of environmental interventions support active lifestyles in rural areas, and populations in rural states like Mississippi are in need of evidence-based guidance. Another issue I think needs to be addressed is increased funding for alternative transportation infrastructure that is safe, accessible, and useful, such as complete routes of protected bicycle lanes. There is a fair amount of infrastructure being built, but it is being done with small pots of money so it is often insufficient in terms of safety for bicyclists and for getting riders where they need to go.

DO SOMETHING! Translating and scaling-up research into practice is what often separates public health from other scientific disciplines. New knowledge is generated from well-designed research studies in all fields. Because public health is action oriented, new research findings need to be translated into action to improve health. New vaccines, new policies to reduce workplace injuries, and new strategies to improve the quality of drinking water are examples of research-to-practice translations. Can you think of others?

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Four kinds of evaluation strategies are important to physical activity programming. Formative, process, outcome, and cost-effectiveness evaluations are concerned with different types of questions and should be conceptualized accordingly. Physical activity program evaluations can be experimental or observational in design. Each has strengths and weaknesses. Logic models are useful tools to guide evaluation strategies and help overall planning for program design and implementation. Following six critical steps to program evaluation will facilitate its success. Data from well-designed physical activity evaluation projects strengthen our understanding of cause and effect.

WEB RESOURCE ACTIVITIES The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Ding D, Lawson KD, Kolbe-Alexander TL, Finkelstein EA,

Katzmarzyk PT, Van Mechelen W, Pratt M and Lancet Physical Activity Series 2 Executive Committee. 2016. The economic burden of physical inactivity: A global analysis of major non- communicable diseases. The Lancet 388 (10051): 1311-1324.

Laine J, Kuvaja-Köllner V, Pietilä E, Koivuneva M, Valtonen H, Kankaanpää E. 2014. Cost-effectiveness of population-level

physical activity interventions: A systematic review. American Journal of Health Promotion 29 (2): 71-80.

Reger-Nash B, Bauman A, Cooper L, Chey T, Simon KJ, Brann M, Leyden KM. 2008. WV Walks: Replication with expanded reach. Journal of Physical Activity and Health 5: 19-27.

U.S. Department of Health and Human Services. 2002. Physical Activity Evaluation Handbook. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. www.cdc.gov/nccdphp/dnpa/physical/handbook/pdf/handbook.p df. Accessed 1 June 2010.

U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Division of Nutrition and Physical Activity. Brown DR, Heath GW, Martin SL, eds. 2010. Promoting Physical Activity: A Guide for Community Action, 2nd ed. Champaign, IL: Human Kinetics.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

2.1.1, 2.1.3, 2.3.1, 2.3.2, 2.3.3, 3.1.1, 3.1.2, 3.1.3, 3.2.1, 3.2.2, 3.4.1, 3.4.2, 3.7.1, 3.8.1, 3.8.2, 3.8.3, 5.5.1, 5.5.5, 5.5.6

CHAPTER 16 Partnership Development and Advocacy

OBJECTIVES After completing this chapter, you should be able to discuss the following:

»  What partnerships are and how they advance public health

»  The importance of developing public health partnerships to promote physical activity and exercise

»  Nine key questions for developing effective partnerships

»  How to educate, collaborate, and engage with external partners

»  What health advocacy is and its importance in public health

»  Strategies for global advocacy of physical activity and exercise

»  A detailed example of partnership development for promoting physical activity and exercise in a large population

OPENING QUESTIONS »  What do you think of when you hear the word partnership? »  Are there different kinds of partnerships? »  How could, or would, forming collaborative public health

partnerships help in the promotion of physical activity and exercise?

»  What strategies would you develop or implement to develop effective collaborative partnerships to promote physical activity and exercise?

Partnerships. The word conjures many images: partnerships in business, dancing, life, and government (such as the United Nations). Partnerships involve the joining of two or more persons or organizations for the purpose of achieving a common goal. Implied in that definition is that both the rewards and the risks of a joint venture are shared between the partners.

As the field of public health has evolved, it has become apparent that population-wide health improvement, including disease prevention and health promotion, must focus at a level broader than that of the individual. The medical model of a health care system that treats sick people is inadequate to address larger population and societal health problems. In public health, contrary to the medical

model, health (and disease) are considered in relation to systems, environments, social forces and norms, and regulations. Each of these factors, in turn, influences health behavior and disease outcomes at the population and individual levels. Because of these overarching influences, public health relies on partnerships to work across sectors of influence to effect systemic change. The goal is a shared responsibility (risks and rewards) for improving population health.

Partnerships are necessary in the field of physical activity and public health. Physical activity, and barriers to physical activity, occurs throughout the day during leisure (discretionary) time, occupational physical activity, transportation-related physical activity, and school physical education. These areas are all opportunities in which to engage in physical activity, yet they rarely join together to achieve a common goal. The private health club industry (with gymnasiums and fitness centers) does not see a role for itself in school-based physical education to promote physical activity in children. State departments of transportation, with their emphasis on increasing capacity for motor vehicle travel (and reducing traffic congestion) pay little attention to increasing opportunities for active transportation with bicycle lanes and sidewalks.

Because of the broad societal implications of increased physical activity, partnerships are critical to the emerging field of physical activity and public health. Partnership development refers more to working with organizations than individuals via collaboration. Calise, Moeti, and Epping (2010) offer a detailed explanation of how to develop successful partnerships. The basic concepts are provided here.

All partnerships are not created equal. Generally, they fall into one of three categories: cooperation, coordination, or collaboration. Cooperation partnerships are usually less formal and less structured than the other forms. For example, two organizations can agree to partner to promote physical activity in a community, yet

each continues with its respective work. They may share resources and communicate on a regular basis, but not much else happens.

Coordination partnerships are more formal and structured around the compatibility of the mission statements of all the partners. An example would be two or more groups united to promote physical activity by sharing resources (e.g., personnel, finances, other tangible support) toward a common goal (e.g., a community physical activity promotion campaign). Coordination partnerships are more in- depth and formalized than cooperation partnerships.

Finally, collaboration partnerships are the most organized and structured form of physical activity partnering, uniting groups or individuals (or both) toward a common cause or mission (e.g., the global promotion of physical activity and exercise). Collaboration partnerships are the most formalized type of partnership, involve some written understanding among the partners, and require a shared long-term goal. Collaboration partnerships are characterized by substantial resource sharing (e.g., personnel, facilities, equipment, funding), statements of shared objectives, and mutual accountability for shared work. Clearly, the different types of partnerships have different expectations and levels of effectiveness. However, not all organizations have the ability or the resources to support collaboration partnerships. The key is that partners unite toward a common cause—promoting physical activity.

What types of partnerships have you been involved with? Why were they successful or unsuccessful?

KEY FACTORS IN BUILDING PARTNERSHIPS How are partnerships built? What should you look for in potential partners? How will you know that the partnership is working? There are no easy answers to these questions, and they can be different for various types of partnerships. Nine key questions that can increase the chance of successful partnerships for public health and physical activity promotion are shown in table 16.1. Although answering each of these questions will not guarantee an effective

partnership, it should increase the probability that the partnership will work as intended.

U.S. NATIONAL PHYSICAL ACTIVITY PLAN The U.S. National Physical Activity Plan (Pate 2009, Bornstein et al. 2014) is an excellent example of a partnership with the goal of increasing physical activity for the sake of public health. Although the research indicating the health consequences of physical inactivity is substantial (and growing), no unified approach to improving the physical activity levels of Americans was attempted prior to 2008. National action plans had existed for tobacco control, heart disease control, and other health issues, but not for physical activity. Moreover, six other countries had already established plans that focused specifically on physical activity (Australia, Northern Ireland, Norway, Scotland, Sweden, and the United Kingdom). The extent of inactivity in the United States combined with the overall health benefits that can be realized if a higher proportion of Americans were more physically active made it clear that a comprehensive set of strategies, including policies, practices, and initiatives, to increase physical activity participation in the United States was needed. A partnership was born.

With leadership from the U.S. Centers for Disease Control and Prevention (CDC), a coordinating committee (leadership) was established. Because physical activity (and inactivity) is pervasive in the United States, a multisector partnership was established. The partnership brought together representatives from transportation and community planning, educational, public health, mass media, health care, public health and recreation, and fitness and sport organizations. Later efforts included partnerships with business and industry and faith-based settings.

The long-term goal of the partnership was to create a social movement that would dramatically increase the level of physical activity participation throughout the country. Broad-based input was solicited from stakeholders and others who might contribute to the

overall goal. Finally, evaluation strategies were built into the partnership’s work from the start. This would allow for monitoring the effectiveness of the partnership, its partners, and the progress toward its goal.

Table 16.1   Key Questions for Effective Public Health Partnerships

Key question Importance

Do I need a partnership to accomplish my physical activity and public health objectives?

If the answer is no, then a partnership may not be effective and, in the worst case, could get in the way.

Who should I recruit?

Effective partnerships are most frequently helpful when each partner brings unique skills and resources. Partners with overlapping resources can be less helpful. Partners with no resources are not partners.

Once the partnership is created, who should lead?

Strong, collaborative leadership, and a leadership plan, are critical to successful public health partnerships. A clear understanding of the overall goal of the partnership as well as the goals of the individual partners is critical.

What are the goals of the partnership?

Clearly defined, agreed-upon, and communicated goals are critical to minimize miscommunication and differing expectations among partners.

What is the level of involvement and cooperation of each partner?

As detailed in the text, partnerships can be at the level of cooperation, coordination, or collaboration depending on the interest and resources that partners bring.

How will the partnership operate?

Successful partnerships most often are those with a clear organizational structure. All partners should be clear on their roles and expectations for bringing or helping to locate resources to achieve the desired goal.

On what should the partnership focus?

Although day-to-day decisions and short-term objectives require energy, it is important to keep an eye on the long-term, overarching goal—that is, the reason the partnership was established.

How do we get to our long-term goal?

Successful partnerships, although always needing to focus on the long-term goal, must set a plan of achievable short-term objectives. When attained, the sum of the short-term objectives should help attain the long-term goal.

Is the partnership working?

Evaluation is critical to an effective partnership. Is progress toward the common goal being made? What parts of the partnership are effective? What needs improvement? Are other partners needed? Evaluation in public health partnerships should be ongoing and integrated into the fabric of the partnerships.

Adapted from Calise, Moeti, and Epping (2010).

The U.S. National Physical Activity Plan was launched in May 2010 and revisions to the plan were added in April 2016. The partnership was the only way such an effort could be undertaken and brought to a positive conclusion. The partnership has now moved to specific strategies to implement the plan. More details and updates can be found on the National Physical Activity Plan website (www.physicalactivityplan.org).

LEADERSHIP STRATEGIES TO LEVERAGE PARTNERSHIPS The Imperative for Leadership and Collaboration The critical first step to effectively improve the health of a community through increased physical activity is to establish a coordinated leadership effort that can ensure collaborative investment of resources within that community. The approach selected by any given community should be shaped by the local community’s size, resources, needs, and interests.

Community Goals and the Tools to Achieve and Measure Them Having established a leadership strategy that provides effective coordination of resources and efforts, a community will be poised to assess local priorities, set goals and targets, and to define the measures they will use to track progress.

Strategies and Resources to Reach Community Goals and Targets

Evidence-Based Strategies. Both for the purposes of effectively improving health and for supporting good

proposals for funding, implementing evidence-based

interventions is the most effective way to use

limited resources. Many proven and promising

interventions are available to achieve better health

and to get the greatest return for the investment of

resources and effort.

Reaching Priority Populations. A key reason for using population-based approaches is to increase community

leaders’ ability to reach beyond cultural differences

and socioeconomic barriers that adversely affect some

areas of their community more than others. The

planning process that includes assessment, goal and

objective setting, strategy selection, and evaluation

must include a continuous focus on needs of priority

populations.

Getting the Resources and Sustaining the Initiative.

With clear targets and a plan to achieve them, a

community leadership team and the respective sector

representatives working to implement programs will be

more fully prepared to articulate how requests for

funding will be used.

Return on Investment. Community leaders promoting physical activity initiatives are in a uniquely

strong position when it comes to advocating for their

initiatives. That is because the science connecting

increased physical activity to health improvements is

solid; and there is strong evidence that investments

in improving health through physical activity result

in cost savings for individuals and employers and

more.

Implementing and Evaluating Plans to Increase Physical Activity After the leadership team has assessed needs and priorities; set goals, objectives, and measures; chosen evidence-based strategies; and procured resources necessary to begin working toward the objectives, it is time to begin implementing the plans established.

STRATEGIES FOR PHYSICAL ACTIVITY ADVOCACY

Public advocacy involves recommending, advancing, and supporting a particular cause or policy. Physical activity advocacy, therefore, involves publicly advancing and supporting improved health through increasing physical activity. Clearly, such an enormous task could take a variety of directions, from advocating for more school physical education, to improving access to places to be active, to improving city planning to create environmental supports for physical activity.

Shilton (2008) made the case that physical activity public health intervention has convincing scientific evidence and a broad support base to justify its global advocacy. As he reported, the World Health Organization (1995) defined advocacy for health as “a combination of individual and social actions designed to gain political commitment, policy support, social acceptance and systems support for a particular health goal or program” (Shilton 2006, 119). In keeping with the public health theme (as opposed to the medical model, which focuses on the individual), Shilton also noted that “the key goal of physical activity advocacy is not individual behavioral change, but achieving advances in political commitment, policy support, infrastructure, funding, and systems changes” (Shilton 2006, 766).

LEADERSHIP AND PERSISTENCE The importance of strong leadership in developing public health partnerships cannot be underestimated. Leadership does not have to consist of just one person; it can come from a team or executive committee (as with the U.S. National Physical Activity Plan just discussed). By definition, partnerships are inclusive—the voices of all interested partners are heard. The contributions and interest of partners can wane without strong leadership to help all partners focus on the long-term goal—whether that goal is to increase physical activity participation at the state or national level, at the local community level, or at a worksite. The leadership team needs to be tenacious and persistent to reach the long-term goal and to continue

beyond the goal with cycles of reevaluation, reassessment, reprioritizing, choosing new strategies to reach new priorities, and then starting the cycle over again.

One need not reinvent the wheel to be a successful advocate for physical activity; lessons learned from successful public health initiatives can enhance advocacy efforts for physical activity. For example, Shilton (2008) summarized the results of antismoking interventions that have positively affected public health policies globally (as first reported by Yach et al. 2005). The dramatic decrease in tobacco smoking in the United States is an outcome of years of multifaceted work; advocacy assisted in this process tremendously. Lessons Learned From Successful Antismoking Campaigns

1. A small group of dedicated, persistent, media-savvy, and politically astute leaders and agitators can have a significant effect on public policy.

2. Broad-based support and well-networked coalitions are needed. 3. Commitment to a comprehensive package is crucial—in this

case, a 10-point plan. 4. Interventions known to be effective must be fully implemented. 5. The issue of individual versus environmental action must be

addressed early, often, and well. 6. Acknowledging the evidence of harm is necessary but not

sufficient for policy change. 7. Decades of effort may be required.

A persuasive case can be made that as long as a disconnect exists between the scientific evidence regarding how physical activity improves health and the lack of programs and policies that support physical activity for the health of populations, advocacy strategies for physical activity promotion should be a priority. As covered in previous chapters of this textbook, the evidence that physical activity

improves health is substantial and growing. We also know the types of strategies that work to promote physical activity. Partnerships must now advocate for a long-term commitment to such strategies to improve public health.

How does one go about becoming an advocate? Advocacy in public health is more art than science, but several key steps have been identified. Figure 16.1 illustrates five critical steps to successful physical activity advocacy.

FUNDING Funding public health partnerships is always a challenge. Where does the financial support come from? How do we apply for support? How should a person or organization budget for a project? The answers to these and other questions differ with each project and partnership. A complete treatment of grant writing is beyond the scope of this text. However, a good place to begin looking for initial financial support is members of the partnership organizations. When collaborative partners bring start-up money with them, early work is easier to accomplish.

State and local health departments, although never flush with money, can be useful places to start seeking funding. Community partners such as corporate supporters, parks and recreation departments, and departments of transportation and education all can be investigated. Private foundations and local community foundations often have a keen interest in health and health promotion. Partnerships are particularly attractive to funders because of their naturally inclusive nature. Another resource would be a local college or university; faculty members frequently have additional ideas about securing sources of funding. In short, there is no one way or source for funding partnerships in physical activity and public health. You are limited only by your energy and your creativity.

Figure 16.1   Five steps to successful physical activity advocacy. Adapted from Shilton (2008).

The first step to effective public health advocacy is to establish the urgency of the problem in a way that decision makers and other advocates can understand it. That urgency is most credibly established with a solid grounding in the research of a particular problem (i.e., the science base). The stronger the science, the easier the case for urgency can be made. In the case of physical activity and public health, the science base that has established physical inactivity as a leading cause of death, various noncommunicable diseases, and disability in the world is a very important starting point in expressing the urgency.

Unfortunately, amassing a science base does not, by itself, make the case for change. It is necessary, but not sufficient. Even the strongest public health science is not usable unless it is understood by decision makers and policy makers as well as other advocates. Although a municipal legislator is unlikely to read the most current peer-reviewed paper on determinants of physical activity from a scientific journal, she is likely to read fact sheets, websites, and summaries that succinctly and credibly convey the urgency of the problem.

WHO IS AN ADVOCATE?

The answer to this question is—anybody. Anybody can be an advocate for change for increasing physical activity opportunities, places, and access. Decision makers to influence aren’t just elected officials. They can be school principals, workplace supervisors, or neighborhood associations. Decision makers can even be family members. Change doesn’t happen by accident—advocates make changes faster than they might happen naturally. One program—the Active Life Movement in Austin, Texas, USA—teaches adolescents and teenagers how to be effective advocates for healthy change (www.activelifemovement.org).

Once the urgency of the problem has been established in an understandable fashion, it must be creatively communicated to people who can make a difference. This may be as simple as making a presentation to a corporate human resources director regarding how much money in health care costs might be saved if the corporation began a physical activity promotion program. Alternatively, it could be a multipronged, systematic approach to inform governmental agencies about the problem. For example, people involved with health and health promotion could be approached with a summary of the improvements in health that might be realized if the prevalence of people meeting physical activity guidelines increased by a certain percentage. People involved with transportation and city planning might be approached with estimates of how much traffic congestion may be reduced in a certain neighborhood if bicycle lanes and sidewalks were added to encourage physical activity.

What happens to teamwork and performance when you lose a rower or two?

Communicating the urgency of the problem to people who have the ability to do something about it is not sufficient to effect change. Advocates must be ready to offer credible solutions that preferably have been shown to work elsewhere. Once decision makers have been convinced of the need to do something, they need guidance on what that something is. Evidence-based strategies that have been shown to increase physical activity are reviewed in chapters 11 through 14 of this textbook.

LEADER PROFILE Alejandra Jáuregui de la Mota, PhD

Why and how did you get into the field of Physical Activity and Public Health? I have been passionate about physical activity since childhood. I started playing volleyball when I was 7 years old and continued to play through my undergraduate studies when I was part of the volleyball selective team at my university. During my adolescence and young adulthood I was also an indoor cycling instructor and a swimming teacher, and I went mountain biking during my leisure time. I was so passionate about exercising and enjoyed outdoor activities so much that I was convinced every single person on earth should be able to experience the many benefits of physical activity. That was when I realized I wanted to dedicate myself to helping others engage in and enjoy physical activity.

However, I lived in Colima, Mexico, a small town on the Pacific coast with only a few graduate opportunities. I was very good at math and chemistry, and finished my undergraduate studies in chemistry, biology and pharmacy, despite knowing I would never dedicate myself to analyzing blood or urine samples, or work at a pharmacy. I soon started looking for a graduate program related to physical activity; at that time I had no understanding of public health. I applied to a master’s degree program in physiology at Universidad de Extremadura, in Spain, and a program in Community Health at the University of McGill, in Canada. I also applied to a master’s degree program at the National Institute of Public Health of Mexico (NIPH)— mainly because I was interested in the work of Dr. Salvador Villalpando, who had led some studies exploring

physical activity patterns in preschool children. I got accepted into all three programs, but the NIPH was the only one to offer me a scholarship. That is how I got into the field of public health.

For my Master of Science in Public Health degree program, I explored how physical activity patterns of preschool children changed when entering elementary school, and how these changes affected body composition. That is how I managed to combine my interests in physical activity and public health.

Did any one person have a major influence on your career? How? There are three people who were major influences on my career, and who I now consider my mentors: Dr. Deborah Salvo, Dr. Michael Pratt, and Dr. Bill Kohl. They have taught me how to be open, patient, and unselfish with knowledge. They have also been responsible for my professional growth and have guided me on how to create, lead, and maintain the new department of physical activity at my institution.

Finally, another major influence on my career has been my husband. He has always supported my professional interests, has encouraged me to be the best I can be, and has reminded me of my passion for the simple things, such as playing volleyball.

What are your current interests in the field of Physical Activity and Public Health and how do you translate them into practice? I have two main interests in the field of Physical Activity and Public Health. The first is global, the second is personal. My global interest is to develop this area of research in my home institution, the National Institute of Public Health of Mexico, and in Latin America at large. One of my professional goals is to position physical activity in the policy agenda of my country, as it has been neglected in the past years. Despite the urgent situation of noncommunicable diseases in Mexico, especially diabetes and obesity, and the implementation of bold strategies at the national level aiming to improve the diet of Mexicans (i.e., soda tax and regulation of foods in elementary and middle schools), most strategies are focused on promoting healthy habits among individuals,

leaving the responsibility of living a healthy lifestyle up to each person. In this vein, I have pushed for the inclusion of environmental research at my institution by helping develop and chair the new Department for Physical Activity and Healthy Lifestyles, which focuses on understanding not only the physical inactivity pandemic or unhealthy eating, but also the role that space and place have in determining health.

More personally, my main research interests are related to the role of policy: social and built environments for promoting healthy lifestyles, physical activity and healthy dietary intake, and preventing noncommunicable diseases, especially obesity and diabetes. I have collaborated with several groups with the objective of documenting the national situation related to physical activity promotion, understanding the environment for physical activity and healthy nutrition, and developing policy recommendations to improve our national policies.

I am based at the NIPH, so we have very strong ties with the Ministry of Health and other international agencies, and since 2016 we have fostered new relationships with the Ministry of Education and the Ministry of the Environment. For example, along with United Nations Educational, Scientific and Cultural Organization (UNESCO), Pan American Health Organization/World Health Organization (PAHO/WHO), federal ministries, and more than 30 experts in the field, we developed a series of recommendations to implement a national strategy for quality physical education in the Mexican school system. More recently, we have been working closely with the new presidential administration to implement these recommendations, along with a whole-of-school approach for physical activity promotion in all elementary and middle schools in the country.

Why do you do what you do? Because I love it.

What are two key issues that must be addressed by 2030? There are two major issues which I believe are the most pressing: chronic diseases and poor quality of life. Fortunately, I believe that addressing these public health problems may require similar approaches—building healthier and more sustainable cities in which the healthy choice is

the easy and preferred one. This will need to be addressed not only through the public health arena, but will also require aligning the interests of many sectors at many levels. I believe this is the only solution.

Evidence of successes in other physical activity initiatives can also be helpful to advocates. What are other people doing or saying about physical inactivity? Are there other examples of advocacy leadership that can assist? One very appropriate example is the Toronto Charter for Physical Activity (Bull et al. 2010). The Toronto Charter, published in 2010, is a call for more political and social commitment on the national level to support health-enhancing physical activity. It advocates the following four actions: (1) implementing a national plan for physical activity promotion; (2) introducing policies that support physical activity; (3) reorienting services and funding to make physical activity a priority in education, transportation and planning, the built environment, worksites, sports, parks and recreation, and health care; and (4) developing effective partnerships for action. The Toronto Charter asserts that physical inactivity is a global problem and must be addressed throughout society.

THE WHO GLOBAL ACTION PLAN FOR PHYSICAL ACTIVITY The World Health Organization (WHO) has taken a global leadership position with a 12-year action plan to promote physical activity throughout the world. The vision for the global action plan is “more active people for a healthier world” and the overarching mission is to “ensure that all people have access to safe and enabling environments and to diverse opportunities to be physically active in their daily lives, as a means of improving individual and community health and contributing to the social, cultural and economic development of all nations.” The plan prioritizes four strategic objectives and 20 specific

policy actions within the objectives, which, if implemented, could increase global physical activity

levels. Clearly such an ambitious plan demands multiple partnerships because the agenda is beyond the scope of any single agency. By working together to achieve the vision of this global action plan and improve health for all, partners can also accelerate progress to achieve their own respective goals. For more information on the WHO Global Action Plan for Physical Activity, explore the website www.who.int/ncds/governance/physical_activity_plan/en/.

Because change does not usually happen by chance, the fourth step in physical activity advocacy is to develop and enact an advocacy strategy. Such a strategy can involve both the political and media arenas. Communicating with organizations in these arenas should be frequent to raise the profile of the issue and create a demand for change. Although less frequently addressed, professional networks and community organizations with similar advocacy interests can amplify the message. Enlisting more advocates can be very beneficial to a cause.

Finally, translating and communicating the urgency to decision makers (step 2) may not be sufficient. Shilton (2008) calls for creative persuasive communication tactics that keep an issue prominent in the media. Creative use of the popular media such as television, the Internet, and print can go a long way in getting the attention of decision makers and policy makers. Creating a demand for change can often drive that change faster than the most passionate advocate.

CHAPTER WRAP-UP WHAT YOU NEED TO KNOW

Partnerships (relationships that focus on mutual cooperation and responsibility) are needed to promote physical activity

and exercise. Partnerships can be categorized as cooperation, coordination, or collaboration. There are several steps to building partnerships in physical activity and public health. The goal of physical activity advocacy focuses less on individual behavioral change, and more on achieving advances in political commitment, policy support, infrastructure, funding, and systems changes. Community physical activity plans should include leadership and collaboration; goals and the tools to measure them; strategies and resources to reach goals and targets; and implementation and evaluation plans. Physical activity advocates should communicate the urgency of the problem, offer solutions, provide evidence of the successes of other initiatives, use an effective advocacy strategy, and communicate that strategy well. The WHO Global Action Plan for Physical Activity is an example of using partnerships to develop a road map for increasing physical activity globally.

WEB RESOURCE ACTIVITIES

The web resource provides a variety of interactive activities to help you learn and understand the information presented in the text. You’ll find e-Media links, flash card activities, and test questions when you visit the page for this chapter.

BIBLIOGRAPHY Bull FC, Gauvin L, Bauman A, Shilton T, Kohl HW, III, Salmon A.

The Toronto Charter for Physical Activity: A Global Call to

Action. J Phys Act Health 2010; 7(4):421-422. Bornstein D, Pate RR, Buchner D. 2014. Development of a

national physical activity plan for the United States. Journal of Physical Activity and Health 11: 463-469.

Calise TV, Moeti R, Epping JE. 2010. Developing partnerships. In Brown DR, Heath GW, Martin SL, eds. Promoting Physical Activity: A Guide for Community Action, 2nd ed. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Division of Nutrition and Physical Activity. Champaign, IL: Human Kinetics.

Pate RR. 2009. A National Physical Activity Plan for the United States. Journal of Physical Activity and Health 6 (Suppl 2): S157-S158.

Shilton, T. 2006. Advocacy for physical activity: From evidence to influence. International Union for Health Promotion and Education 13 (2): 118-126.

Shilton, T. 2008. Creating and making the case: Global advocacy for physical activity. Journal of Physical Activity and Health 5: 765-776.

World Health Organization. 1995. Report of the inter-agency meeting on advocacy strategies for health and development: Development communication in action. Geneva, Switzerland: World Health Organization.

Yach D, McKee M, Lopez AD, Novotny T. 2005. Improving diet and physical activity: 12 lessons from controlling tobacco smoking. British Medical Journal 330: 898-900.

PHYSICAL ACTIVITY IN PUBLIC HEALTH SPECIALIST This chapter covers these competency areas as set forth by the National Physical Activity Society:

1.1.1, 1.1.2, 1.1.5, 1.1.6, 1.2.1, 1.2.2, 1.4.3, 2.2.1, 2.2.2, 3.4.1, 3.4.2, 3.4.3, 3.6.2, 3.6.3, 3.6.4, 4.2.5, 4.3.3, 4.5.1, 4.5.4, 4.6.4

GLOSSARY

absolute intensity—The rate of energy expenditure required to perform any given physical activity. Often measured in METS, kilocalories (kcals), or miles per hour (mph) for activities like walking or running; expressed in pounds (lb) or kilograms (kg) for the amount lifted in resistance training. absolute strength—The maximum amount of force one can exert, or maximum amount of weight that one can lift one time and no more (or one repetition max, 1RM). accelerometers—Small piezoelectric devices that estimate physical activity energy expenditure by measuring movement. Specifically, they measure the magnitude and direction of acceleration. They constitute an indirect measure of physical activity. accelerometer sampling rate—The number of data points that an accelerometer records per second. access—In broad terms, access is the ability to approach or use something. In a physical activity and public health context, it includes geographic access (availability and accessibility) and economic access (ability to pay to use a resource, such as a gym). accumulation—Acquiring a specific dose of physical activity or exercise to achieve a specific goal (such as health, physical fitness, or peak performance) by performing several shorter bouts, then adding together the time spent during each of these bouts (e.g., three bouts lasting 10 minutes each to achieve 30 minutes of daily physical activity or exercise).

action stage—The fourth stage of the transtheoretical model, in which a previously sedentary person has recently become physically active and is perhaps now meeting the physical activity guidelines of 150 minutes per week of moderate-intensity physical activity. active transport—Walking, cycling, or other human-powered methods (e.g., skateboarding) of transportation. activities of daily living (ADLs)—Minimal self-care activities that a person must accomplish each day. Examples include bathing, dressing, feeding, and using the toilet. adverse cardiac event—A composite term to describe several acute cardiac abnormalities. In relation to physical activity and exercise, the two most frequently studied events are cardiac arrest and sudden cardiac death. advocacy—Public support for advancing a defined cause, causes, or policy. aerobic activities—Forms of activity that are intense enough and performed long enough to maintain or improve an individual’s cardiorespiratory fitness. Aerobic activities commonly require the use of large muscle groups. aerobic capacity—Activities that stress the ability to maintain high percentages of O2max for extended periods of time (e.g., 20 minutes or longer). aerobic power—Activities that require high levels of oxygen delivery to the working muscles and last from 3 to 15 minutes. affect—The feeling that results from being physically active. For example, the amazing feeling of scoring a goal compared to the general intent to stay physically fit is what motivates some people to be physically active. age-related decline in cognitive function (also known as age- related cognitive decline or normal cognitive aging)—The gradual loss of cognitive abilities over time (vocabulary, conceptual reasoning, memory, processing speed) due to aging.

air displacement plethysmography—A technique based on the same displacement principles as hydrostatic weighing that uses multiple sensors in the measurement unit to measure air displacement in a known period of time. all-cause mortality—Death due to any cause. Alzheimer’s disease—The most prevalent type of dementia, with symptoms including memory loss and behavioral and cognitive problems that deteriorate over time. anaerobic activities—High-intensity activities that exceed the capacity of the cardiovascular system to provide oxygen to muscle cells for the usual oxygen-consuming metabolic pathways. Anaerobic activity can be maintained for only a short period of time, about 2 to 3 minutes. Sprinting and powerlifting are examples of anaerobic physical activity. anaerobic capacity (or mean peak power)—Short-burst, high- intensity movements that last between 15 seconds or up to three minutes, and stress additional anaerobic energy pathways of the body. anaerobic power (or peak power)—Short-burst, high-intensity movements that last less than 15 seconds and stress the anaerobic energy pathways of the body. anorexia nervosa—A psychological eating disorder characterized by abnormally low body weight and excessive fear of weight gain. atherogenic dyslipidemia—Low high-density lipoprotein (HDL) levels and high triglyceride levels with small, dense low-density lipoprotein (LDL). audit—A method of measuring the built environment based on direct observation through inventories, and allowing for quantifying aspects at the community and street levels. basal metabolic energy expenditure (BMEE)—The energy expended to maintain breathing and circulation while at rest; usually expressed as kilocalories.

bioelectrical impedance analysis (BIA)—A technique that sends a low-amperage electrical current through surface electrodes on the body (e.g., the wrist and ankle), and the measurements of the resistance to the current permit the estimation of body composition using prediction equations. biomechanics—The study of physics applied to the understanding of movements in living organisms. biostatistics and data science—The application of mathematical and statistical techniques to the analysis of public health problems. body composition—The relative proportion and distribution of fat, lean mass (muscle and bone), and minerals in the body. body mass index (BMI)—A frequently used screening measure that takes into account a person’s height as well as weight. To calculate BMI, divide weight in kilograms by height in meters squared:

BMI = weight (kilograms) / height (meters2) body weight status—A concept encompassing issues related to weight gain, loss, and maintenance. bone mineral density—A measurement of the amount of calcium and other minerals in a segment of bone, usually measured at the hip or lower spine. bone strengthening activities—Physical activities that maintain or improve muscular strength (how much resistance can be overcome), endurance (how many times or for how long can resistance be overcome), or power (how fast can the resistance be overcome). built environment—Any aspect of the environment, urban or rural, that has been created by people. This can include structures like sidewalks, roads, stoplights, crosswalks, buildings, and parks. bulimia—A psychological eating disorder characterized by bouts of extreme overeating (bingeing) followed by bouts of depression and self-induced purging. cancer—A group of diseases with processes associated with uncontrolled abnormal cell growth and proliferation.

cardiovascular disease (CVD)—The cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels that include coronary heart disease (CHD or ischemic heart disease, heart attacks), cerebrovascular disease (stroke), elevated blood pressure (hypertension), peripheral artery disease, rheumatic heart disease, congenital heart disease, and heart failure. chronic diseases (or noncommunicable diseases)—Illnesses that are not caused by a specific infectious agent. classroom activity breaks—All activity performed in the classroom during classroom time regardless of intensity. clinically significant weight loss—A loss of at least 5% of body weight. co-benefits—Positive aspects resulting from a physical activity strategy beyond increases in physical activity. These may include reduced air pollution, more social interaction, lower crime, and better equity. In some circumstances, physical activity promotion may be the co-benefit of a program or policy with a different primary goal than increasing population levels of physical activity. cognitive function—Cerebral processes involved in thinking and knowledge acquisition, including attention, reasoning, memory, and language. collaboration—Working with one or more other person(s) to produce a common product. The most organized and structured type of partnership, in which the partnership is formalized in writing and the two organizations share a long-term goal. Community Guide (officially known as the Guide to Community Preventive Services)—A collection of evidence-based findings and recommendations from the Community Services Task Force designed to be a resource to improve health and prevent disease. community-wide campaign—A recommended informational approach to increase physical activity using highly visible, broad- based multicomponent strategies.

compliance—People’s ability to continue to participate in regular physical activity or exercise programming. Comprehensive School Physical Activity Programs—A school- based, multicomponent approach that is designed to increase physical activity. computed tomography (CT)—A research and medical diagnostic tool that relies on X-ray technology to quantify the amount of fat tissue and other tissue in the body or in a region of the body. connectivity—A concept referring to the ease of getting from one place to another within a neighborhood while using the road network of a city to walk or bike. In a part of the city where the streets follow a grid pattern, it is easy to use the street network (assuming sidewalks or bicycle lanes are available) to move around by walking or bicycling. In parts of the city where intersections are very far from each other, or there are a lot of dead-end streets or culs-de-sac, connectivity is considered to be suboptimal. contemplation stage—The second stage of the transtheoretical model, in which a person may be thinking about making a change to be physically active a short time in the future, and may be aware of the benefits, but has not yet reached a tipping point to make the behavior change. cooperation—Working together or complying with requests. Cooperation usually involves a less formal partnership, in which two organizations share resources and communicate on a regular basis. coordination—Organization of multiple inputs or elements to make it easier to produce a common product. Coordination tends to be a more formal partnership in which two organizations unite to promote a cause by sharing resources towards a common goal. cost-effectiveness evaluation—A component of program evaluation focused on estimating the overall costs of program delivery, how these costs compare with those of alternative program delivery options, and how the costs of program or policy delivery and

implementation compare to the cost of not delivering the program or policy. counts (accelerometry)—A numerical value, in an arbitrary scale, assigned to the acceleration recorded by an accelerometer in a given time point. cut points (accelerometry)—Physical activity intensity thresholds derived by formulas converting counts per epoch (usually counts per minute) to energy expenditure values. Cut points indicate the minimum number of counts per minute (for this example) to be met to categorize a minute as being of sedentary, light, moderate, or vigorous intensity. Cut points are brand- and age-specific. decisional balance—A person’s ability to weigh the pros and cons of being physically active and to take action based on that assessment. delivery alternatives—A critical component of a well-conducted process evaluation. Program delivery policy implementation can be improved by testing it against an alternative designed for the same purpose. dementia—A group of symptoms related to loss of memory and cognitive skills that are serious enough to lower a person’s ability to perform everyday tasks. Alzheimer’s disease is the most common type of dementia. detraining—The loss of health or fitness following the cessation of a regular program of physical activity or exercise. diabetes mellitus (or diabetes)—A syndrome associated with low insulin secretion, a limited ability of insulin to act on target tissues to maintain glucose homeostasis, or both of these conditions. direct observation—The only direct measure of physical activity behavior; uses trained observers to collect standardized data on physical activity intensity and type occurring at specific settings by groups of people (e.g., students in a PE class, users of a park). domains—The reason for or purpose of a given physical activity behavior, which includes discretionary time domain (also referred to

as free-time or recreational domain), transportation-based domain, occupational domain, and household domain. dose-response—The amount of physical activity or exercise needed for achieving health, physical fitness, or performance goals. dose-response analysis—An analysis examining if the response to a physical activity program or policy depends on the dose of the program or policy to which a person was exposed. Three or more evaluation groups are needed to conduct a dose-response analysis. dose-response relationship—The relationship between the amount of an exposure (e.g., physical activity) and the overall response of an organism (e.g., a health outcome, like cancer). In physical activity research, the amount of physical activity needed for achieving health, physical fitness or performance goals is expressed as a dose-response relationship. dual-energy X-ray absorptiometry (DXA)—A technique in which X- ray beams are emitted and data are differentiated into fat mass, fat- free mass, and skeletal (bone) mass in a two-dimensional display. The DXA technique can provide precise data about a person’s percentage of body fat, as well as bone mineral density data. dynamic physical activity or exercise—Physical activity that usually requires muscle-shortening (concentric) and muscle- lengthening (eccentric) movements. dysthymia (also known as Persistent Depressive Disorder)—A condition of chronic mild depression. economy—The energy cost of physical activity or exercise at a given speed or workload. Educating the Student Body Report—A major report from the Institutes of Medicine in 2013 that detailed six major recommendations for action needed to improve opportunities for physical activity in school children, using school as the hub for these activities. effectiveness studies—Studies in which the main outcome of interest relates to how well a treatment works in practice—or more

appropriately—in real life instead of in controlled settings. efficacy trials—Studies that are used to establish that a certain intervention or public health program can change a certain condition. environmental health—The branch of public health that focuses on the built and natural environments and their effect on health. epidemic—The occurrence of cases of an illness, specific health- related behavior, or other health-related events clearly in excess of normal expectancy in a community or region. epidemiology—The study of the distributions and causes of diseases in defined populations. Epidemiology is the basic science of public health. epochs (accelerometry)—A time segment at which accelerometer data is aggregated (e.g., 1-second, 10-second, 30-second, 60- second). For example, when data are aggregated at the 60-second epoch length, all data points (counts) collected within a 1-minute period are averaged. essential fat—Fat needed to maintain normal bodily functions. It is important for stored energy, cushioning and insulation, and vitamin absorption; it is found in and around the nervous system, heart, lungs, kidneys, spleen, intestines, and muscles. The minimal amount of essential fat for men has been estimated to be 3% of body weight; for women the estimate is around 12% of body weight. When essential body fat falls too low, health risks for chronic disease and adverse immune reactions increase. excessive weight gain—A change in body weight of more than 2 kg per year or 10 kg per decade; or, a weight increase of more than 3 percent. exercise—A specific type of physical activity that is planned, repetitive, and done for a specific purpose (e.g., to improve health or physical function, physical fitness, or peak performance). exercise physiology—The study of how body structures and functions are altered by acute bouts of exercise or physical activity, and how the body adapts to the chronic stress of physical training.

experimental evaluation studies—A type of evaluation study design considered to be the gold standard of evaluation studies. These types of studies are characterized by randomization of people or communities to an intervention group (those that will receive the physical activity program or policy) and control or comparison group (those that will not receive the physical activity program or policy). exposure—Any factor that is hypothesized or studied as being causally related to a defined outcome of interest. fasting plasma glucose (FPG) test—A test used to diagnose diabetes or prediabetes in which blood glucose is measured after an eight-hour fast. If the glucose level is 99 mg/dl or below, the test is normal. A glucose level of 100 to 125 is consistent with prediabetes or impaired fasting glucose; a person with these levels is at higher risk for type 2 diabetes. If the level is 126 or higher, the person has diabetes. Fitnessgram—A comprehensive set of assessment procedures for physical education programs that includes health-related physical fitness field tests that assess aerobic capacity; muscular strength, muscular endurance, and flexibility; and body composition. FITT—Frequency, intensity, time, and type (mode) of exercise. formative evaluation—The first level of a physical activity program evaluation, in which the fundamental questions focus on the needs, utility, and design features of a physical activity promotion program or policy and its individual components. functional ability—The capacity to perform a task, activity, or behavior independently. functional health or physical function—The engagement in regular physical activity both individually and in populations, or to move around and to perform types of physical activity. Measures of physical function include measures of ability to perform one’s desired activities of daily living like: walking (e.g., usually gait speed), running, climbing stairs, carrying groceries, sweeping the floor, standing up, and bathing.

geographic information systems (GIS)—Computational mapping methods that allow for the analysis of geographic and social data (e.g., distances, landmarks, density, traffic, crime, resources, green space) by overlaying data in map format from multiple sources. Global Physical Activity Questionnaire (GPAQ)— Standardized international surveillance instrument for physical activity, modeled after IPAQ, its predecessor. GPS waypoints—Geographic location points recorded continuously (every 5 to 15 seconds) by Geographic Positioning Systems (GPS) monitors, which include data on latitude, longitude, date stamp, time stamp, and altitude, and from which travel velocity can be derived. gross energy expenditure—The combination of physical activity or exercise energy requirements with resting energy expenditure. health administration and policy—The field of public health that focuses on health care administration, leadership, and management. health education—Education that encompasses strategies to increase or maintain personal health. health promotion—The process of enabling people to increase control over, and to improve, their health. It moves beyond a focus on individual behavior towards a wide range of social and environmental interventions. health-related PE (HRPE)—A concept that promotes public health objectives and focuses on the health benefits of physical activity. Healthy People 2020—Health goals that are updated every 10 years by the U.S. Department of Health and Human Services that highlight disparities and opportunities for health improvement by setting public health targets to achieve in a 10-year period. high intensity interval training (HIIT)—Physical activities or exercises that require working at a higher intensity for a few seconds or minutes followed by working at lower (recovery) intensities, which can vary in training bouts.

hypertrophy—The enlargement of an organ or tissue from the increase in the size of its cells. ideal body fat/ideal body weight—An optimal percentage of body fat or value of one’s body weight that is highly variable and should be based on factors such as age, sex, personal goals, behaviors, and appropriate educational messaging that does not promote addictive disorders (i.e., eating or exercise). implementation fidelity—The extent to which the program or policy is being implemented as originally planned. incidence—a measure of disease frequency for the occurrence of new cases of a disease or outcome of interest over a specified period of time. individually adapted behavior change programs—Physical activity promotion strategies that integrate key components of the health behavior theories and theoretical models to help people change and maintain physical activity behaviors. The evidence base behind these types of programs is strong, and these strategies work when implemented appropriately. infectious diseases—Illnesses due to a specific infectious agent or its toxic products that arise through transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host. informational approaches—Strategies designed to increase physical activity that rely on the transmission of information. initiation (cancer)—The first stage of the multistage model of carcinogenesis. In this stage, genetic material is altered, and affected cells are more likely to grow more rapidly than unaffected cells. insomnia—Difficulty in sleeping at night. instrumental activities of daily living (IADLs)—Activities that a person must be able to accomplish to live independently. Examples include using a telephone, housekeeping, meal preparation, and laundry.

insulin resistance—A condition in which cells become slow to respond or unresponsive to the effects of insulin, which gives them the signal to absorb glucose from the bloodstream. Insulin resistance is a risk factor for the development of diabetes. International Physical Activity Questionnaire (IPAQ)—First standardized international surveillance instrument for physical activity. interventions—A public health action, preferably at the community level, designed to improve health. kinesiology—An academic discipline that addresses the interrelationship of physiological processes and the anatomy of the body with respect to movement. land use (zoning)—The management, planning, and development of land in defined jurisdictions. light-intensity activity—Activity requiring 1.6 to 3.0 METs, such as walking at a slow pace (2 mph or less) or cooking. logic model—A critical tool for program evaluation in which a graphic or narrative description of processes and interrelationships can lead to a result (cause and effect). Logic models describe and define the relationships between resources, the target population, short-term and long-term effects, and the ultimate desired outcomes of a program or policy. macro-environmental urban design (also known as community- scale urban design)—The aspects of the built environment at a large scale, usually spanning several square miles (or kilometers), and normally defined as an administrative unit like a neighborhood, zip code, school district, city, or county. magnetic resonance imaging (MRI)—A research and medical diagnostic tool that relies on X-ray technology to quantify the amount of fat tissue and other tissue in the body or in a region of the body. MRI is thought to be a safer technique largely because it does not rely on ionizing radiation.

maintenance stage—The fifth and final stage of the transtheoretical model, in which a person has been consistently active for at least six months. mass media campaign—The use of mass media channels to deliver messages about physical activity to large audiences. Mass media campaigns are designed to increase awareness or knowledge of the health benefits of physical activity, and are a type of informational approach that does not have enough evidence to be recommended by the Community Guide. MET—A metabolic equivalent or 3.5 ml . kg–1 . min–1 of oxygen uptake, which is equal to the resting energy expenditure for an average person. meta-analysis—A study compiling findings from the best studies of a given topic and statistically combining these data findings to determine strength of the evidence for that topic. metabolic syndrome—A cluster of clinical characteristics (with similar profiles in adults and adolescents) that include atherogenic dyslipidemia, elevated fasting glucose or insulin levels, hypertension, and excess abdominal obesity. metastases—The process by which a cancer spreads to organs and systems other than their site of origin. micro-environmental urban design (also referred to as street- scale urban design)—The aspects of the built environment in small geographic areas, generally limited to a few blocks. moderate-intensity activity—Activity requiring 3.0 to less than 6.0 METs, such as walking briskly (3 to 4 mph), mopping or vacuuming, or raking a yard. mood disorders—Psychological disorders that are characterized by changes (increases or decreases) in a person’s mood (e.g., depression). motor behavior—The study areas of motor learning, motor control, and motor development.

motor control—The study of human information processing and the integration of motor movements that involve motor planning and execution. motor development—The study of changes in motor behavior of the lifespan. motor learning—The study of how we learn and perform motor skills such as cycling and dancing. It also addresses the concepts that influence motor skills negatively or positively. movement sciences—The study areas of motor learning, motor control, motor development, and biomechanics. multistage model of carcinogenesis—A useful model to study the development of cancer through three basic stages: initiation, promotion and progression. muscle dysmorphia—A psychological disorder characterized by negative body image and the intense desire to have a muscular physique. muscle mass—The bulk of skeletal muscle in the human body. musculoskeletal injury—An acute disorder in a bone, muscle, joint, or connective tissue that is attributable to exercise or physical activity. narcolepsy—A condition of extreme sleepiness during the day. National Physical Activity Plan (NPAP)—A comprehensive set of policies, programs, and initiatives designed to increase physical activity in all segments of the U.S. population. natural environment—The physical aspects of the environment that were not created or altered by people. Examples include national parks, rivers, lakes, the ocean, or the weather. needs assessment—A source of data for formative evaluations with the general purpose of gathering information from the target population (or one that is similar) of a planned physical activity program or policy.

net energy expenditure—Physical activity or exercise energy requirement, or gross energy expenditure minus the resting energy requirements. No Child Left Behind—An act passed by the U.S. Congress in 2001 supporting standards-based education reform and including provisions for disadvantaged students. numerator monster—A mythical creature that arises when cases of an outcome of interest are counted but the population from which those cases came from (the denominator) is not. Without the denominator, following the numerator monster will lead to fallacious conclusions about rates and risks. nutritional diseases—Nutrient-related conditions that cause disease in humans. obesity—Having an unhealthy body weight, which is consistent with a variety of disease processes such as CVD, metabolic syndrome, and type 2 diabetes. observational evaluation studies (often referred to as quasi- experimental designs)—A type of evaluation study design in which people or groups are divided into treatment and control groups based on convenience, receptivity, targeting, and other factors. These types of evaluation study designs differ from experimental ones in that they are not randomized. oral glucose tolerance test (OGTT)—A test used to diagnose diabetes or prediabetes in which blood glucose is measured after an eight-hour fast and two hours after ingesting 75 grams of glucose dissolved in water. If the glucose level is 139 mg/dl or below, the test is normal. A glucose level 140 to 199 is consistent with prediabetes or impaired fasting glucose. If the level is 200 or higher, the person has diabetes. osteoarthritis—The degeneration of joint cartilage and the underlying bone, most common from middle age onward. It causes pain and stiffness, especially in the hip and knee joints.

osteoporosis—A medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D. outcome evaluation (also referred to as impact evaluation)—A step of a physical activity program evaluation focused on cause and effect. Outcome evaluation examines whether the program or policy has the intended effect on the outcome of interest or not. For the purposes of physical activity promotion programs and policies, the outcome of interest usually refers to increased levels of physical activity due to the program or policy. overload principle—Improvement in health and physical fitness that are directly related to increases in FITT variables by gradually increasing the physical stress on the body. overtraining—Participating in too much physical activity or exercise without taking the time to recover appropriately. overweight—Carrying more body fat than is healthy or an amount that increases disease risk. partnership—The state of officially combining resources (people, finances) with one or more other entities or people to work toward a common goal. physical activity—Any bodily movement that recruits skeletal muscles and results in energy expenditure (i.e., expending calories). physical activity and exercise continuum—The process where one should become physically active while avoiding sedentary behaviors and seek to achieve specific health, physical fitness, and/or peak performance based on individual or population goals. physical activity energy expenditure (PAEE)—The energy expenditure that is specifically the result of physical activity, usually expressed as kilocalories. physical environment—A broad term encompassing all the physical aspects of the environment that surround us. This can include the roads in a city or the lamp posts, but also topographical aspects (e.g., steepness of a hill). There are two main types of

physical environmental features: those of the built environment and those of the natural environment. physical fitness—A set of measurable physiological parameters such as cardiorespiratory endurance (aerobic power), skeletal muscle endurance, skeletal muscle strength, skeletal muscle power, flexibility, balance, speed of movement, reaction time, and body composition. place activation—Programming activities and communication or informational strategies to get people to use a built environment resource (e.g., a new park or trail). precontemplation stage—The first stage of the transtheoretical model, in which a person has not even thought about becoming physically active or may be unaware of the importance of being physically active. preparation stage—The third stage of the transtheoretical model, in which a person has reached that tipping point and is making small changes in behavior (e.g., taking the stairs rather than the elevator); in this stage, the person may be looking for support from friends and family as this new stage of activity begins. Presidential Youth Fitness Program—A comprehensive school- based program that promotes health and physical activity for America’s youth. The program includes online challenges and allows participants to keep track of their progress toward individual goals. prevalence—total number of individuals with a disease or outcome of interest at a point or period in time (may be a health behavior, like achieving sufficient levels of physical activity for health). process evaluation—A step of a physical activity program evaluation focused on implementation. The main interest when conducting a process evaluation is to determine how well the physical activity program or policy is operating and what can be done to improve those operations. program evaluation—The process of collecting and analyzing data to determine if a program is necessary or feasible, if it is being

implemented optimally, if it is as impactful as intended, and if it is cost-effective. progression (cancer)—The third stage of the multistage model of carcinogenesis. In this stage, proliferating precancerous cells become full, invasive tumors, and cancer is subsequently diagnosed. progression/adaptation—How the body (muscles, tissues, organ systems) reacts over time to overload and specificity in the context of physical activity and exercise. promotion (cancer)—The second stage of the multistage model of carcinogenesis. In this stage, initiated cells become precancerous through additional genetic changes as a result of the altered state they entered in the first (initiation) stage. The promotion stage is characterized by rapid proliferation of altered cells. psychological distress (also known as mental distress)—A series of symptoms resulting from unpleasant emotions or feelings that can impact someone’s overall level of functioning in everyday life. public health—The art and science of preventing disease, prolonging life, and promoting health through the organized efforts of society. public health law—The part of public health that examines the role of policy and government in promoting health and preventing disease. public health surveillance—The ongoing, systematic collection, analysis, and interpretation of health-related data essential to the planning, implementation, and evaluation of public health practices. quality of life—One’s satisfaction with life that includes health- and nonhealth-related aspects. random plasma glucose test—A test used to diagnose diabetes or prediabetes in which blood glucose is measured (nonfasting) when a person has diabetic symptoms such as increased urination, increased thirst, unexplained weight loss, fatigue, blurred vision, increased hunger, or sores that do not heal. If the glucose level is above 200 mg/dl, the person probably has diabetes.

randomization—The arbitrary assignment of people, groups of people, or settings (e.g., schools or hospitals) to receive or not receive an intervention or treatment. reactivity—The tendency to modify one’s habitual behavior after becoming aware that you are being measured or observed. recall bias—The inability to accurately recall, or the selective recall of only certain activities. relative intensity—The rate of energy expenditure as a percentage of maximum effort like the percent of O2max, percentage of maximal heart rate, or perception of effort on self-report scales. relative strength—The amount of force one can exert or the weight they can lift for 1RM divided by their body weight. resistance training—Activities to improve strength, power, and muscular strength and endurance such as weight training or using flexible bands. response bias—When participants provide false or inaccurate responses to questions. restless legs syndrome—A sleep movement disorder characterized by the urge to move one’s legs while trying to fall asleep. risk factors—Lifestyle or genetic variables that can predict the occurrence of disease. role ability—The ability to successfully perform both activities of daily living and instrumental activities of daily living. sedentary activity—Activity requiring 1.0 to 1.5 METs, such as sitting and reading or watching television, or standing quietly. sedentary behavior—Any waking behavior characterized by an energy expenditure of 1.5 or fewer METs while sitting, reclining, or lying. The majority of office work, driving a car, and sitting while watching television are examples of sedentary behaviors. Sedentary behavior and sedentary activity are similar but not synonymous; both

are limited to energy expenditures 1.5 or fewer METs, but sedentary activity includes standing. self-efficacy—In a physical activity behavior context, it refers to the confidence or perceived ability that a person may have to be physically active and deal with the external threats and barriers that could result in slowing, stopping, or reverting progress. self-esteem—A general feeling of confidence and satisfaction with oneself. SHAPE America (Society of Health and Physical Educators)—A professional organization promoting health and physical activity. skinfold measurement—Measurements of skinfold thickness at various sites on the body (e.g., the triceps, abdomen, and thigh) that provide an estimate of subcutaneous fat (about 50% of total body fat) and therefore an estimate of body density and the percentage of body fat. sleep apnea—A potentially serious disorder, characterized by upper airway blockage during sleep and resulting in the interruption of breathing during sleep. sleep disorders—Alterations in the way that one sleeps that affect health and quality of life. social capital—The factors that contribute to cohesive and well- functioning societies; elements of high social capital include a shared sense of community and feeling that you can trust your neighbors. social desirability bias—Responding to a question based on what you feel others (including the interviewer) expect or consider good. social environment—A level of the socioecological model of behavior; it refers to how society is composed or how it behaves as a whole, beyond the people that we directly know or interact with in our daily lives. social support—A broad concept that generally refers to any strategy for developing or strengthening the interpersonal

connections or the social environment of people to encourage (or overcome barriers to) physical activity. socioecological model of behavior—A conceptual framework and visual representation for understanding the multiple factors that influence physical activity, and therefore the potential solutions to encourage activity. The basic principle is that although the behavior (physical activity) occurs at the individual level, it is influenced by factors of multiple levels (individual, interpersonal, social environment, built environment, policy). SOFIT (system for observing fitness instruction time)—A validated direct observation tool for instructional settings that measures both group-based levels of physical activity and quality of the class. SOPARC (system for observing play and recreation in communities)—A validated direct observation tool for public open recreation settings that measures both group-based levels of physical activity and environmental indicators of the social and physical context of the settings. specificity principle—A principle based on the fact that changes in health and physical fitness are dependent on adjusting FITT variables for the desired adaptations and outcomes. sport and exercise psychology—The study of behaviors and outcomes related to participation in sports or programs of exercise training. stakeholders—People and organizations with direct or indirect interests in a physical activity project, program, or policy. state anxiety—Acute feelings of stress due to confrontation with a specific situation, place, or object. static (or isometric) physical activity or exercise—Physical activity that is anaerobic in nature and requires an increase in force production with limited range of motion. thermic effect of food (TEF)—The amount of energy that is used to digest and metabolize energy that is ingested (food and drink).

Usually expressed as kilocalories. total energy expenditure (TEE), also referred to as total caloric expenditure—The combination of one’s resting metabolism (basal metabolic energy expenditure), thermic effect of food, and physical activity energy expenditure over time, usually expressed as kilocalories. training plateaus—Training periods when little, if any, improvement occurs with increased levels of physical activity or exercise. trait anxiety—refers to individual variations to state anxiety (see state anxiety). Trait anxiety is a relatively stable aspect of a personality, i.e., the differences in a person’s response to stressful situations, places, events, or objects. transtheoretical model—A theoretical model of health behavior, based on a five-category continuum of behavior, that is used to classify how prepared a person is to change behavior, or motivational readiness to change or begin. type 1 diabetes—A syndrome in which a person’s immune system attacks and destroys the insulin-producing beta cells of the islets of Langerhans in the pancreas. type 2 diabetes (adult-onset, non-insulin-dependent diabetes mellitus, or NIDDM)—A syndrome related to overweight, obesity, and insulin resistance (IR, impaired glucose homeostasis). underwater (hydrostatic) weighing—A technique that is based on the principle of water displacement (i.e., when you get in tub of water, the water level rises based on the volume your body displaces). In this technique, a person’s weight is measured both in and out of water. A person with more fat (which is less dense than lean body tissue) will be buoyed up more than a leaner person, and will consequently weigh less in water. urban design—The form, function, and outward appearance of the physical environment in defined entities, such as neighborhoods, towns, cities, and communities.

vigorous-intensity activity—Activity requiring 6.0 or greater METs, such as walking very fast (4.5 to 5 mph), running, mowing grass with a hand-push mower, or participating in an aerobics class. volume—The dose of physical activity or exercise which is related to frequency, intensity, type, and time/duration of physical activity. waist circumference—A measure of girth at the level of the lowest rib or umbilicus level using a cloth measuring tape with a spring- loaded handle; a common way to determine when people are carrying too much abdominal fat for good health. waist-to-hip ratio (WHR)—A simple way to use circumferences to evaluate the distribution of body fat in adults. Health risk increases as WHR increases, and standards vary by age and sex. walkability—A construct capturing the features of the built environment of an urban area that are conducive to walking for transportation. The most common definition of walkability combines high land-use mix, connectivity, and residential density, although this definition is not necessarily applicable to all contexts and settings. weight maintenance (or weight stability)—A weight change of less than 3%, and prevention of weight regain after a substantial loss that is consistent with a change in weight of 3% to less than 5%. weight regain—after a substantial loss, it is consistent with a change in weight of 3% to less than 5%. Whole School, Whole Community, Whole Child (WSCC) Model— A public health framework that U.S. educators are encouraged to use to promote increased school physical activity that includes health education; physical education and physical activity; nutrition environment and services; health services; counseling, psychological, and social services; social and emotional climate, physical environment; employee wellness; family engagement; and community engagement.

INDEX

Note: The italicized f and t following page numbers refer to figures and tables, respectively.

A absolute intensity 26 absolute strength 30 academic performance 218 academic programs, in public health 6 ACC (American College of Cardiology) 85 accelerometers 59-60, 59f, 69 access to physical activity 242-243, 250 accumulation of exercise 24 ACSM (American College of Sports Medicine) 23 action stage 226 Active Australia (case study) 197, 197f active transport 243 activities of daily living (ADLs) 138 adaptation. See progression/adaptation addictive behaviors 164 ADLs (activities of daily living) 138 adult-onset (type 2) diabetes 80, 90, 92f, 95 adults and older adults. See also specific body systems or diseases

balance and stability in 137 balance assessments 133 basal metabolic energy expenditure 107 benefits of physical activity in 38 brain function outcomes in 169f fall risk reduction 137, 140, 141 gait assessments 133 physical activity guidelines for 48, 89t, 90, 118-120, 136-137, 137t quality of life 169 resistance training in 126 sarcopenia in 127 waist circumference measures 116

adverse cardiac events 183-187, 185f

advocacy, of physical activity 9, 279-285, 281f aerobic activities 24 aerobic capacity 25, 139 aerobic power 25 affect 230 age, as risk factor

brain health 165 cancer 149 CVD 82 musculoskeletal disorders 126, 127 musculoskeletal injury 181 obesity 110

age-related cognitive decline 163, 170 Aguilar, Nicolas 253 AHA (American Heart Association) 85, 87 air displacement plethysmography 115 all-cause mortality 78-79, 79f, 88 Alzheimer’s disease 163, 169, 170 American College of Cardiology (ACC) 85 American College of Sports Medicine (ACSM) 23 American Heart Association (AHA) 85, 87 anaerobic activities 24 anaerobic capacity 25 anaerobic power 25 anatomical factors, in injury 181 angiogenesis 167 anorexia nervosa 164 antismoking interventions 280-282 anxiety disorders 163, 164, 170 arthritis 124, 125, 126-127, 134-136 assessment phase, of public health functions 10, 12f assessments. See fitness assessments; measurements of physical activity; program

evaluation assurance phase, of public health functions 10, 12f atherogenic dyslipidemia 80, 81, 83 audits 248 Austin, Texas (case study) 252, 252f availability, of geographic access 242 AV O2 diff 83

B balance

assessment of 133 fall prevention and 137 functional health and 139

barriers, to physical activity 35, 227 Barriers to Being Active Quiz 228f

basal metabolic energy expenditure (BMEE) 57, 107, 111 Bauman, A. E. 196, 197 bed rest, as detraining 35, 135, 135f Behavioral Risk Factor Surveillance System (BRFSS) 69, 70t behavioral sciences. See also physical activity behavior

in history of physical activity and public health 44 physical activity adaptations 82, 84-86, 113, 128, 130 term usage 21 youth and physical activity 209-210

behavior change. See physical activity behavior Berg balance scale 133 BIA (bioelectrical impedance analysis) 115 Bills of Mortality 67 bioelectrical impedance analysis (BIA) 115 biomechanics, defined 20. See also movement sciences biostatistics 10 Black Death (bubonic plague) 4-5 blood glucose levels for active persons 97t BMD (bone mineral density) 124, 129, 133-134, 134f. See also musculoskeletal health and

disorders BMEE (basal metabolic energy expenditure) 57, 107, 111 BMI (body mass index) 102-106, 103t, 104f, 105f, 112f BOD POD 115 body composition

BMI and 103 defined 107 ideal 114 measurement of 114-116, 114f youth outcomes 211, 213

body fat abdominal 111 essential 113 ideal 114 physical activity effects on 83, 107

body mass index (BMI) 102-106, 103t, 104f, 105f, 112f body weight status 111. See also overweight and obesity Bogota, Colombia (case study) 245 bone mineral density (BMD) 124, 129, 133-134, 134f. See also musculoskeletal health and

disorders bone remodeling process 130f bone-strengthening activities 24, 134-135, 136-137, 137t brain health and disorders

common conditions 163-164 defined 162 disorder prevalence and costs 162-163 physical activity effects on 165-171, 166f, 169f physical activity guidelines 173 risk factors 164-165

testing for 168 youth outcomes 213

breast cancer risk physical activity and 146, 151, 157 sex hormones and 153

BRFSS (Behavioral Risk Factor Surveillance System) 69, 70t Brownson, R. 11, 246, 247 bubonic plague (Black Death) 4-5 built environment

access to physical activity and 242-243, 250 Bogota, Colombia (case study) 245 defined 240 influence of 49, 69, 242-243, 254 land use policy 251 measurement of 247-249 Mueller neighborhood (case study) 252, 252f physical activity policy and 249-251, 250f research challenges 243 urban design 244-247 walking trails development (case study) 246

bulimia 164

C Calise, T.V. 252, 276 caloric balance 106-107, 106f calories. See kilocalories calorimetry, indirect 57-58 cancer

deaths from 147, 150t incidence of 148, 150t metastases 146 multistage model of carcinogenesis 148-149, 148f physical activity among survivors 153-154, 154t physical activity effects on 149-157 physical activity guidelines 157 prevalence and costs 146-148 risk factors 149 screening tests 153

cardiac events, sudden adverse 183-187, 185f cardiorespiratory fitness or function (CRF) 86-87 cardiorespiratory health

assessment of 86-87 general recommendations for 87-90 physical activity effects on 82, 83-86, 84f, 88, 129 physical activity guidelines 88-90, 89t youth outcomes 209, 211, 213

cardiovascular disease (CVD)

defined 79 London transport workers study 43-44, 44f physical activity effects on 79-80 prevalence and costs 80 risk factors 79-80, 80-82 secondary prevention of 85

careers in physical activity and public health 49-52. See also leader profiles Carlson, S.A. 183 Centers for Disease Control and Prevention (CDC)

Physical Activity Evaluation Framework 260 surveillance systems 46

Chau, J. 196, 197 Chenoweth, D. 109, 109f children and adolescents

benefits of physical activity in 38 BMI and weight status in 103-106, 104f, 105f brain function outcomes in 169f depression in 164 developmental considerations 211, 212f, 217-218, 218f diabetes in 80, 90 fitness assessments of 210 Let’s Move! initiative 195 obesity prevention in 116, 118 physical activity effects on 208-210, 211-213 physical activity guidelines for 48, 89, 89t, 136, 137t, 213-214 physical activity levels in 214-215 self-report in 65 waist circumference measures 116

cholesterol levels 80, 81, 83 chronic diseases 6, 45 church-based support network (case study) 235 cigarette smoking. See tobacco use citizen scientists 244 clinically significant weight loss 111 co-benefits, of physical activity promotion 254, 259, 270 cognition 163 cognitive function 163, 168-169 collaboration partnerships 9, 276-277 college-based health education (case study) 200 colon cancer risk 146, 150-151, 152-153, 157 combined physical movements 25 commitment strategy 230t communication, of program evaluation results 270-272 Community Guide 192-193, 215-216 community interventions

Active Australia (case study) 197, 197f community-wide promotions 194-196 in public health practice 46-47

social support in 233-235 West Virginia Walks (case study) 269

community-scale urban design 245-247 compliance 23, 35-37 Comprehensive School Physical Activity Program (CSPAP) 207, 216 computed tomography (CT) 114 connected support 229 connectivity, in urban design 246 consumer-based fitness trackers 62 contemplation stage 226 control groups 267-268 cooperation partnerships 276 coordination partnerships 276 cost-effectiveness evaluation 263-264 costs of disease. See economic costs of disease or injury counts (accelerometer data) 59, 60 C-reactive protein (CRP) 81-82 CRF (cardiorespiratory fitness or function) 86-87 crime, and physical activity 247-248 CRP (C-reactive protein) 81-82 CSPAP (Comprehensive School Physical Activity Program) 207, 216 CT (computed tomography) 114 cultural traditions, and obesity 111 cut points

in accelerometer data 60 for populations differences 103

CVD. See cardiovascular disease

D daily voluntary caloric expenditure 23 data collection and analysis

for program evaluation 268-270 surveillance data 46, 67-69, 70t

death. See mortality decisional balance 226-227 delivery alternatives assessment 261 dementia 163, 170, 171 depression 163, 164, 170, 171 detraining 23, 35 diabetes

blood glucose levels for active persons 97t as CVD risk factor 81 description and types 80 physical activity effects on 91-92, 92f, 95 physical activity guidelines 95-97 prevalence and costs 90-91, 91f risk factors 91

tests for 93-94 diagnosis, as public health function 10, 12f diaries (self-report instrument) 64-65 Dietary Guidelines for Americans (2015-2020) 18, 106 diet interventions 111, 112f Ding, D. 263 Ding, Melody 236 direct observation techniques 62-64, 248 discretionary domain 56 diseases. See also specific diseases

in history of public health 4-6 physical activity and prevention of 19, 20f

distress 164, 165, 170, 170f, 171 domains of physical activity 56, 58 dose (volume) of exercise 23 dose-response analysis

colon cancer 150 described 24, 24f, 268 metabolic syndrome 94, 94f type 2 diabetes 92f

doubly labeled water technique 58 dual-energy X-ray absorptiometry (DXA) 114, 114f, 133 Dunn, A.I. 166, 232 duration (time) of exercise 22, 30, 31t DXA (dual-energy X-ray absorptiometry) 114, 114f, 133 dynamic physical activity or exercise 25 dysthymia 164

E economic access 242 economic costs of disease or injury

brain and mental health disorders 162-163 cancer 147-148 CVD 80 falls 138 metabolic disease 90 osteoarthritis 125 osteoporosis 124 overweight and obesity 108-109, 109f

economy of movement aerobic capacity and 25 physical activity effects on 84 weight loss or maintenance and 113 in youth 209

effectiveness studies 47 efficacy trials 46-47 Ekelund, Ulf 201-202

electronic fitness devices 58-62, 59f, 60f, 61f, 66 empowerment, in public health 9, 10, 12f endurance activities 136 energy expenditure

by activity 107t age-related decline in 107 calculations of (case study) 32, 32t caloric balance and 106-107, 106f measurements of 23, 56, 57-58, 57f

environment. See also built environment cancer risk and 146, 149 defined 8 influence on health 240-241 influence on physical activity 49, 49f, 69, 242-243 musculoskeletal injury risk and 181-182 types 240

environmental health 8 environmental health sciences 45 epidemics 4-5 epidemiology 6-7, 43, 45f epoch (accelerometer data) 59 essential fat 113, 114 estrogen 126, 153 ethnicity. See race or ethnicity evaluations. See program evaluation evidence-based public health 193 excessive caloric intake 110 excessive weight gain 111 exercise, defined 16, 56. See also physical activity and exercise exercise/heart hypothesis 44 exercise physiology

body composition adaptations 112, 113 brain health adaptations 167 cardiorespiratory adaptations 82, 83-86, 84f, 129 defined 19 metabolic adaptations 91-92 musculoskeletal adaptations 128, 129 youth outcomes 209

experimental design studies 266

F falls

economic costs 138 low muscle mass and 127 risk reduction 137, 140, 141

FAM (functional assessment measure) 139 fasting plasma glucose (FPG) test 93

fat. See body fat Fiatarone, Maria 126 fibromyalgia 134 Fick equation 83 FIM (functional independence measure) 139 fitness 16, 56, 181 fitness assessments

balance 133 body composition 114-116, 114f brain health 168 cancer screening 153 cardiorespiratory fitness 86-87 functional health 139-140 gait 133 musculoskeletal health 130-134, 133f obesity and overweight 113-116 in school-based programs 210 as training principle 22, 33-34

fitness devices 58-62, 59f, 60f, 61f, 66 Fitnessgram 210 FITT principles

frequency 30, 31t, 136 intensity 25-30, 25f, 26t, 27f, 136, 167-168, 184, 185 overview 22 time (duration) 30, 31t type 24-25

500 Cities Project 69 food safety 43 force development 129, 129f formal written policies 249 formative evaluations 260-261, 266 FPG (fasting plasma glucose) test 93 fractures

osteoporosis and 126 risk reduction 134, 135

frequency of exercise 22, 30, 31t, 136 functional ability 138, 140-141 functional assessment measure (FAM) 139 functional health

assessment of 139-140 concept of 137-138, 139f defined 22, 137 low muscle mass and 127 physical activity effects on 140-141, 140f physical activity guidelines 31t, 141 risk factors 138-139

functional independence measure (FIM) 139 funding, for public health partnerships 281

G gait assessments 133 genetics

as brain health risk factor 165 as cancer risk factor 146, 149 as CVD risk factor 82 external influences on 81 individual variation and 22, 31, 33f musculoskeletal health and 126, 127 as obesity risk factor 110

geographic access 242 geographic information system (GIS) 248-249 geographic positioning systems (GPS) 60-61, 60f germ theory 4-5 GIS (geographic information system) 248-249 Global Matrix initiative 214-215 Global Observatory for Physical Activity (GOPA!) 69 Global Physical Activity Questionnaire (GPAQ) 68 goals and goal setting 16, 17f, 22, 31 Gomez, L.F. 245 goniometry 133 GOPA! (Global Observatory for Physical Activity) 69 GPAQ (Global Physical Activity Questionnaire) 68 GPS monitors 60-61, 60f graded exercise testing (GXT) 86-87, 86f GRAD intervention (case study) 200 green space 240 grip strength assessment 132 gross energy expenditure 23 growth charts 103, 104f, 105f Guide to Community Preventive Services 192-193, 215-216

H Han, Ho 36-37 handgrip dynamometry 132, 133f health. See also public health science; specific body systems or diseases

environmental 8, 240-241 functional 22, 31t, 127, 137-141, 138f, 140f, 141 obesity consequences 110 physical activity effects on 24, 24f, 37-38 poverty and 5

health administration and policy 9-10 health belief model 225t health education and promotion

classroom-based 198-202 college-based (case study) 200 defined 198

effective curricula 199 overview 8-9 as public health function 10, 12f WHO Principles of Health Promotion 9 WSCC model 216

health guidelines development 47 health-related PE (HRPE) 215 health-related quality of life. See functional health Healthy People 2020 108, 206, 207 Heart and Soul program (case study) 235 heart disease. See cardiovascular disease high intensity interval training (HIIT) 24-25 Hino, Adriano Akira 119 hip fracture risk 134, 135 HIV/AIDS 9-10 Holloszy, John 94 hormones, and osteoporosis 126 household domain 56 HRPE (health-related PE) 215 hydrostatic (underwater) weighing 114-115 hypertension 81 hypoglycemia 95, 97

I IADLs (instrumental activities of daily living) 138 ideal body fat 114 ideal body weight 114 impact (outcome) evaluations 262-263 implementation fidelity 261-262 inactivity. See physical inactivity inclusion, as health promotion principle 9 indirect calorimetry 57-58 individual factors in physical activity 48-49, 48f, 49f individually adapted programs 229-230, 230t, 232, 232f industrial revolution 5 infectious diseases 4-6, 45 inflammation biomarkers 81-82 informational promotion

Active Australia (case study) 197, 197f classroom-based health education 198-202 community-wide campaigns 194-196 mass media campaigns 196-198 rationale for 194 VERB (case study) 198

initiation stage of carcinogenesis 148 injuries. See also musculoskeletal injuries

defined 178-179

risk of 25, 37, 209 insomnia 164 instrumental activities of daily living (IADLs) 138 insulin-dependent (type 1) diabetes 80, 90 insulin resistance 152, 153 intensity of exercise

adverse cardiac events and 184, 185 for brain health adaptation 167-168 classifications of 25-26, 26t as FITT principle 22 methods for determining 26-30, 27f of resistance training 136

O2 max and 25f International Physical Activity Questionnaire (IPAQ) 68 intersectoral collaboration 9 interval training 24-25 interventions. See community interventions interviews, as physical activity measure 65 IPAQ (International Physical Activity Questionnaire) 68 isokinetic dynamometry 132 isometric physical activity or exercise 25

J Jáuregui de la Mota, Alejandra 283-284 Jewell, J.S. 166 Johns Hopkins School of Public Health 6 joint injuries, and osteoarthritis 127 juvenile (type 1) diabetes 80, 90

K Karvonen formula 27 Katzmarzyk, P.T. 214-215 kilocalories

caloric balance 106-107, 106f excess intake 110 needs formula 106 per minute or hour intensity measure 28 in physical activity measurement 32, 32t, 56 total caloric expenditure 23

kinesiology body weight and 112-113 cancers and 149-153 cardiorespiratory health and 82, 83-84, 84f defined 17 epidemiology merger 45f metabolic health and 91-92

musculoskeletal health and 127-130, 129f, 130f, 131f musculoskeletal injuries and 182-183 subdisciplines of 18-21 traditional training model 16, 17, 18f youth outcomes 208-210

Kraus, William E. 96

L lactate threshold (LT) 83 Laine, J. 263 Lancet Series on Physical Activity 68 land use policy 251 law, public health 12-13 leader profiles

Adriano Akira Hino 119 Alejandra Jáuregui de la Mota 283-284 Andrea Ramirez Varela 155-157 Anna Porter 271-272 Geoffrey P. Whitfield 72 Ho Han 36-37 I-Min Lee 50-51 James Sallis 172-173 Melody Ding 236 Michael Pratt 186 Nicolas Aguilar 253 Peter Silvius 219 Ross Brownson 11 Sandra M. Mahecha 142 Ulf Ekelund 201-202 William E. Kraus 96

leadership 279, 280 Lee, I-Min 50-51 leisure-time domain 56 Let’s Move! initiative 195 Leutzinger, J. 109, 109f life expectancy 42 lifestyle behaviors, and brain health 165 light intensity 25 logic model 264-266, 264f, 267f London School of Tropical Medicine and Hygiene 6 London transport workers study 43-44, 44f low muscle mass 124, 127 LT (lactate threshold) 83

M McKenzie, Thom 63

macro-environmental urban design 245-247 magnetic resonance imaging (MRI) 114 Mahecha, Sandra M. 142 maintenance stage 226 male pattern fat distribution 111 mass media campaigns 196-198 maximal heart rate (MHR) 26-27, 83, 84f maximal oxygen uptake. See O2max mean anaerobic power (anaerobic capacity) 25 measurements of physical activity

choosing method of 71, 71f combined approaches 71 direct observation techniques 62-64 electronic devices for 58-62, 59f, 60f, 61f, 66 laboratory techniques 57-58 self-report instruments 64-67 surveillance data 67-69, 70t

media campaigns 196-198 medicine, versus public health 4 mental health disorders. See brain health and disorders MET (metabolic equivalent) 23, 27-28, 32, 32t meta-analysis (term) 151 metabolic adaptations 91-92 metabolic diseases. See diabetes; metabolic syndrome metabolic equivalent (MET) 23, 27-28, 32, 32t metabolic health, in youth 211-213 metabolic syndrome

assessment of 92-94 as CVD risk factor 81 described 80 diagnosis criteria 91t physical activity effects on 91-92, 94-95, 94f physical activity guidelines 95-97 prevalence and costs 90 risk factors 91

metastases 146 mhealth strategies 230 MHR (maximal heart rate) 26-27, 83, 84f micro-environmental urban design 244-245 Mitchell, J. 35 Mittleman, M.A. 185 mobility limitations. See functional health mobility tests 133 mode (type) of exercise 22, 24-25 moderate intensity 26 modifications, as training principle 22, 34 monitoring function, of public health 10, 12f

mood disorders 163-164, 170 Moore, S.C. 78 Morris, Jeremy N. 43-44, 44f mortality

cancer deaths 147, 150t leading causes of death 6, 6t, 46t physical activity correlation 78-79, 79f, 88 sudden cardiac death 183-187, 185f

motivation 22, 33 motor behavior 20 motor control 20 motor learning 20 movement sciences

adaptations in youth 209 brain health adaptations 167 cardiorespiratory adaptations 82 described 20-21 musculoskeletal adaptations 128, 129-130

MRI (magnetic resonance imaging) 114 Mueller neighborhood (case study) 252, 252f multidimensions, in health promotion principles 9 multistage model of carcinogenesis 148-149, 148f muscle dysmorphia 164 muscle mass, low 124, 127 muscle-strengthening activities. See resistance training muscular strength and endurance 132, 139, 209, 211 musculoskeletal health and disorders

assessment of 130-134 disorder prevalence and costs 124-125 fitness and function tests 133f most common disorders 124 physical activity effects on 127-130, 129f, 130f, 131f, 134-136 physical activity guidelines 135, 136-137, 137t risk factors 125-127 youth outcomes 209, 211, 213

musculoskeletal injuries defined 178-179 incidence and prevalence of 179-180, 180t, 182f numerator monster and 179 physical activity effects on 182-183, 183f risk factors 180-183 training principles and 184

N narcolepsy 164 National Health and Nutrition Examination Survey (NHANES) 69, 70t National Health Interview Survey (NHIS) 69, 70t

National Physical Activity Plan (NPAP) 206-207, 277-278 National Physical Activity Society (NPAS) 21, 52 National Public Health Performance Standards Program (NPHPSP) 10 National Society of Physical Activity Practitioners in Public Health (NSPAPPH). See

National Physical Activity Society natural environment 240 needs assessments 261, 266 negative lifestyle behaviors, and brain health 165. See also physical inactivity; sedentary

behavior and activity neighborhoods, defining 248 net energy expenditure 23 NHANES (National Health and Nutrition Examination Survey) 69, 70t NHIS (National Health Interview Survey) 69, 70t NIDDM (non-insulin-dependent diabetes) 80 No Child Left Behind legislation 208 noncommunicable (chronic) diseases 6, 45 non-insulin-dependent (type 2) diabetes (NIDDM) 80 NPAP (National Physical Activity Plan) 206-207, 277-278 NPAS (National Physical Activity Society) 21, 52 NPHPSP (National Public Health Performance Standards Program) 10 NSPAPPH. See NPAS numerator monster 179 nutrition

cancer and 149 obesity and 111 osteoporosis and 126 public health goals 18

nutritional diseases 5

O OA (osteoarthritis) 124, 125, 126-127, 134-136 Obama, Michelle 195 obesity. See overweight and obesity observational evaluation studies 266-268 obstructive sleep apnea (OSA) 112, 164 occupational domain 56 occupational loads, and osteoarthritis 127 OGTT (oral glucose tolerance test) 93 older adults. See adults and older adults OMNI-Walk/Run Scale 29, 30f 1-repetition maximum (1RM) 29-30, 132, 133f oral glucose tolerance test (OGTT) 93 OSA (obstructive sleep apnea) 112, 164 osteoarthritis (OA) 124, 125, 126-127, 134-136 osteoporosis 124-126, 133-134, 134f outcome (impact) evaluations 262-263 overload principle 22, 34, 184

overtraining 23, 35 overweight and obesity

assessment of 113-116 BMI and weight status 102-106, 103t, 104f, 105f caloric balance and 106-107, 106f as cancer risk factor 149 challenges of 111 as CVD risk factor 81 defined 102 as disease 102 health consequences 110 as osteoarthritis risk factor 127 physical activity effects on 112-113, 116-118 physical activity guidelines 118-120 prevalence trends and costs 107-109, 108f, 109f risk factors 109-111

P PAEE (physical activity energy expenditure) 57, 58, 107t Paffenbarger, Ralph 44, 44f PAGAC (Physical Activity Guidelines Advisory Committee Report)

benefits of physical activity 38 cardiorespiratory health recommendations 88 classification of physical activity 26, 26t as kinesiology and public health integration basis 18 metabolic health recommendations 94-95 mortality and physical activity correlation 78 weight management 116-120

pandemic, of physical inactivity 68 PAR (7-day Physical Activity Recall interviews) 64 Parkinson’s disease 163 participation, as health promotion principle 9 partnerships

funding 281 keys to building 277-278, 278t leadership strategies 279 mobilizing 10, 12f types 276-277

peak power (anaerobic power) 25 pedometers 61-62, 61f perceived exertion (PE) scales 29, 30f perceived support 227 percentage of maximal heart rate 26-27 percentage of maximal heart rate reserve 27 percentage of maximal oxygen uptake 28, 29f performance-related fitness 37 PE (perceived exertion) scales 29, 30f

Peterson, J.A. 235 physical activity advocacy 9, 279-285, 281f physical activity and exercise

adaptations to. See progression/adaptation barriers to 35, 227, 228f benefits of 37-38, 45, See also specific body system or diseases co-benefits from promotion of 254, 259, 270 continuum of 16 defined 16, 56 in disease prevention and rehabilitation 19, 20f domains of 56, 58 energy expenditure calculations (case study) 32, 32t excessive, and osteoarthritis 127 FITT principles 22, 24-30 general guidelines 47-48, 56-57, See also specific body systems or diseases guidelines for youth 48, 89, 89t, 136, 137t, 213-214 as injury risk factor 181, 209 measurements of. See measurements of physical activity mortality correlation 78-79, 79f, 88 physician consult before 187 promotion of. See built environment; informational promotion; school-based physical activity programs traditional training model 16, 17, 18f training principles 22-23, 31-37 youth activity levels 214-215 youth outcomes 208-210, 211-213

Physical Activity and Public Health Specialist 52 physical activity and public health subdiscipline. See also public health science

careers in 49-52 evolution of 42-45, 45f

physical activity behavior factors influencing 48-49, 49f Heart and Soul program (case study) 235 individually adapted programs 229-230, 230t at population level 226 Project Active (case study) 232, 232f social support for 227-229, 233-235 theories and models of 224-227, 225t, 227f, 231-233, 231f

physical activity diaries 64-65 physical activity energy expenditure (PAEE) 57, 58, 107t Physical Activity Guidelines Advisory Committee Report (PAGAC). See PAGAC Physical Activity Guidelines for Americans

functional health guidelines 141 general physical activity guidelines 47-48 importance of 23 as kinesiology and public health integration basis 18 mortality and physical activity correlation 78 muscle-strengthening activity guidelines 136-137, 137t

weight control guidance 106 physical activity policy 249-251, 250f physical activity programs. See program evaluation; school-based physical activity

programs physical education 215-216 physical environment 240 physical fitness 16, 56, 181 physical function. See functional health physical inactivity

as brain health risk factor 165 as cancer risk factor 149 as CVD risk factor 81 emergence of public health issue 44 as functional health risk 139 health risks of 78-79 musculoskeletal health and 125, 126-127, 134-135 as obesity risk factor 110 as pandemic 68

physiology. See exercise physiology pillars of public health 6-10, 7f place activation 242 policy development 9, 10, 12f policy influence

beyond physical activity 254 on physical activity 69, 241-242, 249-251, 250f in social cognitive model 49, 49f

POM (Profile of Mood States) 168 Porter, Anna 271-272 poverty, and health 5 Pratt, Michael 186 precontemplation stage 226 prediabetes tests 93-94 premature death risk 78-79, 79f preparation stage 226 Presidential Youth Fitness Program 210 President’s Council on Sports, Fitness, & Nutrition 210 process evaluations 261-262 Profile of Mood States (POM) 168 program evaluation

co-benefits of 259 cost of 263 data collection and analysis 268-270 design of 266-268 importance of 258-259 logic model for 264-266, 264f, 267f questions in 262 results dissemination 270-272 steps in CDC framework 260

types 260-264, 260f when to begin 258

progression/adaptation brain health 167-168 cardiovascular 82, 83-86, 84f, 129 genetics and 31, 33f injury prevention and 184 metabolic 91-92 musculoskeletal 127-130, 129f, 130f, 131f in overweight and obesity 112-113 as training principle 23, 34-35 in youth 208-210

progression stage of carcinogenesis 149 progressive overload 22, 34, 184 Project Active (case study) 232 Project GRAD (case study) 200 promotion of physical activity and exercise. See health education and promotion;

informational promotion; physical activity behavior promotion stage of carcinogenesis 148 protective equipment use 181 psychological distress 164, 165, 170, 170f, 171 Public Health Functions Project 10 public health guidelines 47-48 public health law 12-13 public health science. See also health

areas (pillars) of specialization 6-10, 7f defined 42 evidence-based 193 focus of 4 functions of 10, 12f, 46-47 future of 13 history and evolution of 4-6, 42-45 subdiscipline 42-45, 45f, 49-52 surveillance data 46, 67-69, 70t training programs 6

Q quality of life 169, 170f. See also functional health quality of well-being scale (QWB) 139 quasi-experimental designs 266-268 questionnaires 65-67

R race or ethnicity

as CVD risk factor 82 diabetes prevalence 90

obesity prevalence 108 as obesity risk factor 110-111 as osteoporosis risk factor 126

Ramirez Varela, Andrea 155-157 randomization 266 random plasma glucose test 93-94 reactivity 62, 64 recall bias 67 received support 227-229 recovery time 23, 35 recreational domain 56 Reger-Nash, B. 269 rehabilitation, and physical activity 19, 20f relative intensity 26, 27f relative strength 30 reminder strategy 230t repetitions, in resistance training 136 research

environmental science challenges 243 translating into practice 46-47, 272

resistance training adaptations to 128-130 as anaerobic activity 24 for frail older adults 126 guidelines 136-137, 137t musculoskeletal health and 134-135 training variables in 30

response bias 67 restless leg syndrome 164 rheumatoid arthritis 134 role ability 138, 140-141 Routemaster bus 43f Routemaster bus study 43-44 running economy. See economy of movement

S Sallis, James 172-173, 200, 217 sampling rate 59 sarcopenia (low muscle mass) 124, 127 Schmid, T. L. 249-251, 250f school-based physical activity programs. See also health education and promotion

activity integration practices 206, 216 assessments in 210 developmental considerations 211, 212f, 217-218, 218f physical activity adaptations in youth 208-210 physical education 215-216 rationale for 206-208

SPARK program (case study) 217, 217f whole-of-school approach 207, 208f

sedentary behavior and activity defined 16 as disease and mortality risk 78-79 weight management and 118 in youth 213

self-determination theory 225t self-efficacy 86, 227 self-esteem 164, 165 self-reports 64-67, 247-248 self-reward strategy 230t sequencing, of media campaigns 196 7-Day Physical Activity Recall (PAR) 64 sex, as risk factor

brain health 165 cancer 149 CVD 82 musculoskeletal disorders 126, 127 musculoskeletal injury 181

sex hormones 126, 153 SF-36 (long) and SF-12 (short) assessments 139 SHAPE America (Society of Health and Physical Educators) 207 Shilton, T. 279-282 Silvius, Peter 219 single-stream campaigns 194 skinfold measurement 114f, 115 sleep apnea 112, 164 sleep disorders 164 sleep improvement 86, 112-113, 169 smartphone apps 62 smoking. See tobacco use social capital 233 social cognitive theory 225t social desirability bias 67 social ecological model 48-49, 49f, 231-233, 231f social environment 243 social influences on physical activity 49, 49f social justice 9 social media marketing 196-198 social norms, as policy influence 250 social support 227-229, 230t, 233-235 Society of Health and Physical Educators (SHAPE America) 207 socioeconomic status, and obesity 111 SOFIT (system for observing fitness instruction time) 63 SOPARC (system for observing play and recreation in communities) 63 SPARK program (case study) 217, 217f specificity principle 22, 34, 184

sport and exercise psychology 21. See also behavioral sciences Sports, Play and Active Recreation for Kids (SPARK) 217, 217f stakeholders 260, 270 state anxiety 164 static physical activity or exercise 25 step counters 61-62, 61f street-scale urban design 244-245 strength training. See resistance training stress management 86 stretching, and injury risk 183 stroke volume, changes in 84f substance abuse 165 substitution strategy 230t sudden cardiac death 183-187, 185f suicidal thoughts 165 sun exposure 149 surveillance data 46, 67-69, 70t system for observing fitness instruction time (SOFIT) 63 system for observing play and recreation in communities (SOPARC) 63

T tai chi 137, 141 talk test 29, 30f target heart rate (THR) 27 Task Force on Community Preventive Services 192 teaching models 22, 33, 33f TEE (total energy expenditure) 57-58, 57f TEF (thermic effect of food) 57 testosterone, and osteoporosis 126 tests. See fitness assessments; measurements of physical activity theory of planned behavior 225t theory of reasoned action 225t thermic effect of food (TEF) 57 thinness, as osteoporosis risk factor 125 THR (target heart rate) 27 time, as barrier to exercise 194 time (duration) of exercise 22, 30, 31t tobacco use, as risk factor

cancer 149 CVD 81 musculoskeletal injury 181 osteoporosis 125

total caloric expenditure 23 total energy expenditure (TEE) 57-58, 57f toxic environmental exposure 149 training

dose response 23, 24, 24f, 268

FITT principles 22, 24-30 plateaus in 34-35 principles of 22-23, 31-37, 184 traditional model 16, 17, 18f

trait anxiety 164 transportation domain 56 transtheoretical model 224-227, 225t, 227f trauma, as brain health risk factor 165 type (mode) of exercise 22, 24-25 type 1 (juvenile) diabetes 80, 90 type 2 (adult-onset) diabetes 80, 90, 92f, 95

U underwater (hydrostatic) weighing 114-115 underweight, as osteoporosis risk factor 125 urban design 244-247, 252 U.S. National Physical Activity Plan 206-207, 277-278 U.S. Report Card on Physical Activity for Children and Youth 214-215

V vaccine development 42 VERB campaign (case study) 198 vertical jump test 133f vigorous intensity 26, 184, 185 vital statistics system 5

O2max (maximal oxygen uptake) aerobic power and 25 in CRF assessment 86-87 exercise intensity and 25f intensity as percentage of 28, 29f physical activity effects on 83, 84f, 129

O2peak 86, 87f volume (dose) of exercise 23. See also dose-response analysis

W waist circumference measures 83, 115-116 waist-to-hip ratio (WHR) 116 walkability 246-247 Walk a Hound, Lose a Pound model 267f walking trails development (case study) 246 Wang, Y. 108 way points, on GPS device 60 wearable fitness devices 58-62, 59f, 60f, 61f, 66 web-based media 196-198 weight management 111-112, 112f. See also overweight and obesity

West Virginia Walks (case study) 269 Whitfield, Geoffrey P. 72 WHO (World Health Organization) 6, 6t, 9, 285 whole-of-school approach 207, 208f Whole School, Whole Community, Whole Child (WSCC) model 216 WHR (waist-to-hip ratio) 116 Wingate anaerobic power test 133 workload anaerobic method 30 worksite physical activity access 250 World Health Organization (WHO) 6, 6t, 9, 285 written standards 250 WSCC (Whole School, Whole Community, Whole Child) model 216

Y youth. See children and adolescents Youth Risk Behavior Surveillance System (YRBSS) 69

Z zoning and land use 251

ABOUT THE AUTHORS

Harold W. (Bill) Kohl, III, PhD, is a professor of epidemiology and kinesiology at the University of Texas Health Science Center at Houston and the University of Texas at Austin. At the University of Texas Health Science Center, Dr. Kohl also serves as the associate regional dean for academic affairs and international health affairs at the Austin regional campus.

In his recent efforts, he has concentrated on national and international physical activity surveillance and epidemiology issues, as well as program development and evaluation studies for the promotion of school-based physical activity for children and adolescents. He is a fellow of the American College of Sports Medicine (ACSM) and the National Academy of Kinesiology, and he has served as an elected trustee of ACSM. He is the founder and past president of the International Society for Physical Activity and Health and currently serves as the elected chair of the U.S. National

Physical Activity Plan Alliance. He has served in an editorial capacity for several scientific journals and is editor emeritus of the Journal of Physical Activity and Health. He has published more than 200 papers, chapters, and monographs in the scientific literature. In 2018 he coauthored the textbook Foundations of Kinesiology.

Tinker D. Murray, PhD, is a professor emeritus and honorary professor of international studies in health and human performance at Texas State University in San Marcos. He earned his PhD in physical education from Texas A&M University in 1984. His research interests include school-based and clinical-based youth physical activity and interventions with public health linkages for the prevention of obesity and diabetes, continuing education opportunities for coaching education, and personal fitness and training applications related to exercise physiology.

From 1982 to 1984, Murray served as director of cardiac rehabilitation at Brooke Army Medical Center, where he was twice recognized for his exceptional performance. He began his career at Texas State University (formerly Southwest Texas State), where he served as the director of employee wellness from 1984 to 1988 and director of the exercise performance laboratory from 1984 to 2000. He was a volunteer assistant cross country and track coach at

Southwest Texas State from 1985 to 1988 and helped win three Gulf Star Conference titles.

From 1985 to 1988, he was a subcommittee member for the Governor’s Commission on Physical Fitness that developed the Fit Youth Today program. He served as lecturer and examiner for the USA Track and Field Level 2 coaching certification program from 1988 to 2008 and as the vice chair of the Governor’s Commission on Physical Fitness in Texas from 1993 to 1994. He worked with the Texas High School Coaches Association (THSCA) from 2003 to 2013 as a facilitator with the Professional Development Cooperative, which promoted continuing education opportunities.

Murray is a fellow of the American College of Sports Medicine (ACSM) and is certified as an ACSM program director. He was a two-time president of the Texas regional chapter of ACSM (1987 and 1994). He served on the national ACSM board of trustees from 1998 to 2001. In the fall of 2003, he was a guest researcher at the Centers for Disease Control and Prevention (CDC) Division of Nutrition and Physical Activity. He has been actively involved with the International Society for Physical Activity and Health (ISPAH) and has attended several biannual meetings of the International Congress on Physical Activity and Public Health.

Murray retired from Texas State University in 2018 and was named a professor emeritus and honorary professor of international studies. He continues to remain physically active by cycling daily, jogging often, and lifting weights twice a week. He remains academically active by contributing to scholarly presentations and publications that promote physical active lifestyles.

Deborah Salvo, PhD, is an assistant professor of public health at the Brown School at Washington University in St. Louis, where she is a faculty scholar of the Prevention Research Center, the Center for Diabetes Translation Research, and the Institute for Public Health. Before this appointment, she held positions at the University of Texas School Health Science Center in Austin, Stanford University’s Prevention Research Center, and the National Institute of Public Health of Mexico.

Salvo is a native of Mexico City, Mexico, and earned her bachelor’s degree in nutrition and food sciences from Universidad Iberoamericana. She earned her doctorate in biological and biomedical sciences (nutrition and health sciences, public health and epidemiology track) from Emory University in 2013. Her interests lie in understanding the role of built environment on physical activity and health, and in using this evidence to resolve global health disparities. Her work ranges from local projects to multisite international consortia. She has expertise in using, improving, and developing novel methodological approaches that combine physical activity and spatial epidemiological tools to address complex questions on the effects of context on health. Throughout her career, she has facilitated and led international collaborations to support the growth of the field of physical activity and public health on a global

scale, with special emphasis on low- and middle-income countries and populations.

Salvo is the current chair of the Council on Environment and Physical Activity within the International Society for Physical Activity and Health. She is also part of the steering committee of the Global Observatory for Physical Activity, and she is an active member of the Our Voice Global Network. Salvo serves as associate editor for Preventing Chronic Disease, an official scientific journal of the Centers for Disease Control and Prevention. Throughout her career, she has served as technical advisor on physical activity and the built environment for several agencies, including the Centers for Disease Control and Prevention, the Fogarty International Center within the National Institutes of Health, the National Institute of Public Health of Mexico, and the World Health Organization. Salvo was a contributing author to the second series on physical activity published by The Lancet in 2016, which convened global experts to present the latest evidence of the important role of physical activity for public health.