THE ROLE OF RESPIRATORY MUSCLE WARM-UP IN IMPROVING EXERCISE PERFORMANCE AND PULMONARY FUNCTIONS

THE ROLE OF RESPIRATORY MUSCLE WARM-UP IN IMPROVING EXERCISE

PERFORMANCE AND PULMONARY FUNCTIONS

Chapter 1. Introduction

1.1 Intention

The aim of this review was to identify the contribution of respiratory warming to exercise

performance and the respiratory system, specifically respiratory muscles and bronchial airways in

healthy individuals. Many exercise physiologists argue that the respiratory system does not have

a significant impact on the restriction of exercise performance in healthy individuals or athletes

(A. McConnell, 2009). However, the respiratory system still faces various challenges during

intensive training. One example is the regulation of partial pressure of oxygen (O2) and carbon

dioxide in alveoli, which is achieved by increasing alveolar ventilation and minute ventilation

(VE), which often reaches 20 times the resting value in humans. This is achieved thanks to the

capacity of the respiratory muscles to generate force in alveolar ventilation, while reducing

excessive physiological costs on the system during exercise (Guenette & Sheel, 2007). Another

challenge that the respiratory system must face is the ability of the bronchial (intra-thoracic)

airways to maintain patency and allow for the increased airflow required during active expiratory

that often occurs in intensive exercise. During high-intensity exercise, the bronchial airways

sometimes become a significant obstacle to expiratory airflow, which can lead to dynamic

hyperinflation, increased respiratory muscle workload, and VE limitations (Forster et al., 2012).

Research has focused on these two key aspects—respiratory muscle work/fatigue and airway

patency—to identify respiratory system limitations during and after exercise. This review will

discuss both functions as well as potential ways to overcome or reduce the challenges the

respiratory system faces during exercise.

This review is divided into four parts. The first section will provide a general introduction to the

relevant factors in the review of the respiratory system, both during and after exercise, including

exercise-triggered bronchoconstriction (EIB), exercise-triggered asthma (EIA), and expiratory

flow restriction (EFL) analysis. The second part will discuss various methods to train the

respiratory system in order to improve exercise performance. The third section will explore the

different types of heating that can be used to optimize the "refractor period". The final section will

examine the future direction of research based on the findings obtained during this review.

1.2 The Respiratory System: Challenges with Exercise

To understand the mechanisms of respiratory control that occur during exercise, it is

important to refer to studies such as those conducted by Forster et al. (2012), as well as other

studies such as Babb, Wood, and Mitchell (2010) and Miyamoto (1990). The mechanical work

required for lung ventilation, both at rest and during exercise, involves a variety of elastic and

non-elastic mechanisms, including inertia, gravity, and distortion forces on the chest wall

(Guenette & Sheel, 2007). During intensive exercise, there are additional mechanical obstacles

that affect the respiratory system's ability to improve alveolar ventilation (VE), such as the

pumping capacity of the inspirational muscles to generate negative pleural pressure and the

capacity of the intra-thoracic airways to maintain patency allowing for increased airflow rates

during active expiratory (Forster et al., 2012). The total mechanical work is the result of all these

factors. An increase in VE during progressive exercise until it reaches fatigue results in a

disproportionate increase in mechanical work and oxygen expenditure for respiration. However,

in healthy individuals, the dynamic capacity of the inspiration and expiratory muscles to generate

strength may never be a limiting factor in VE's response to exercise (Guenette & Sheel, 2007).

Specifically, at peak training, only about half of the dynamic capacity of the inspiration muscles

is achieved in young adult individuals. For highly trained athletes, about 80-90% of the dynamic

capacity of the inspiration muscles needed to generate the required intra-pleural pressure can

require twice the expenditure of oxygen metabolism (O2) and VE response compared to untrained

individuals (Forster et al., 2012).

An often overlooked ingredient for possible limitations is how the mechanical work of

respiration has sensory and metabolic impacts. The perceived work of breathing contributes to

how hard the exercise feels and the mechanical work demands of the breathing place on the

circulatory system for blood (O2) to maintain muscle contraction are examples of sensory and

metabolic consequences (A. McConnell, 2009). It has been suggested that the metabolic and

circulatory costs of high respiratory mechanical work during maximum levels of VE can amount

to 8-10% of VO2max and cardiac output in untrained individuals and up to 14-16% of VO2max

and cardiac output in highly trained individuals (Aaron, Johnson, Seow, & Dempsey, 1992;

Harms, McClaran, et al., 1998). These findings may represent the inability of the respiratory

system to maintain airway patency in the face of maximum or near-maximum workload, creating

high VE demands and variations in the likelihood of expiratory muscle fatigue due to the changes

in dynamic hyperinflation seen in EFL.

The main muscle of active inspiration in humans is the diaphragm. The diaphragm is a

large, dome-shaped muscle that separates the abdominal cavity and thoracic and is innervated by

the phrenic nerve. It has unique characteristics that make it the most fatigue resistant (very high

aerobic enzymatic capacity, rich blood supply source, and resistance to vasoconstriction) of all

skeletal muscles (Miller, Hemauer, Smith, Stickland, & Dempsey, 2006). Other muscles that can

help the diaphragm with inspiration are the external intercostal, scalaen, and sternocleidomastoid

(accessory muscles). As ventilation increases, the respiratory muscles are recruited. During calm

breathing, there is little to no muscle contraction/relaxation involved in expiration, and retracting

lung elasticity in healthy individuals promotes the process. The abdominal muscles and internal

and deepest intercostal muscles help with forced or active expiration that occurs during strenuous

intensity exercise (Guenette & Sheel, 2007). Recruitment

The diaphragm during exercise can be assessed indirectly through trans-diaphragmatic pressure

measurement (Pdi), surface electromyography (EMG), and the use of bilateral phrenic nerve

stimulation (BPNS) with Pdi. PDI is a measurable difference between gastric and esophageal

pressure and can be assessed during BPNS (bilateral and supra-maximal stimulation of the phrenic

nerve through electrical/magnetic stimulation) (Guenette & Sheel, 2007; Johnson, Babcock,

Suman, & Dempsey, 1993). From studies using this technique, it is believed that the recruited

diaphragm is proportional to an increase in VE with an increase in exercise intensity (Johnson et

al., 1993). Others have proposed that the PDI plateau in the face of increased VE, thus suggesting

that accessory muscle recruitment plays an active role in the total stress generated by the

inspirational muscles (Johnson et al., 1993). Regardless of the contribution of the diaphragm and

accessory muscles, the force output required to maintain VE during intense exercise requires

significant muscle work (O2 demand) and a significant proportion of cardiac output to meet the

applied intensity. Considering the factors of high O2 demand, the required cardiac output, and

high respiratory work, it seems plausible that the diaphragm and accessory muscles may be

susceptible to fatigue (Guenette & Sheel, 2007).

Fatigue in the respiratory muscles is a condition in which there is a decrease in the capacity to

develop muscle force and/or speed, which is caused by activity under weight and which can be

reversed with rest (Macklem, 1990; "NHLBI Workshop Summary. Fatigue of respiratory

muscles. Report of the Respiratory Muscle Fatigue Workshop Group," 1990). The diaphragm

will show significant fatigue during sustained exhaustion training with an intensity greater than

80-85% VO2max (Johnson et al., 1993; Miller et al., 2006). Exercise-induced diaphragm fatigue

is caused by a high level of diaphragm work that must be maintained during high-intensity

exercise. With prolonged high-intensity exercise, hyperventilation is present throughout,

showed that diaphragmatic fatigue did not inhibit ventilator response (Miller et al., 2006).

However, circumstantial evidence from pressure readings suggests that the fatigued diaphragm

reduces its force generation during the final stages of sustained resistance training. This causes the

inspirational accessory muscles and expiratory muscles to become more dominant in maintaining

the work of the respiratory and hyperventilated muscles. This increased use of the expiratory

muscle helps to create a reduction in the volume of the lungs at the end of the expiration, which

increases intra-abdominal pressure, thus allowing the diaphragm to elongate, maintaining its

maximum ability to produce forced (Forster et al., 2012). Some researchers have tried to identify

whether the respiratory muscles can get tired.

When a proportional assist ventilator (PAV) is used during exercise, diaphragmatic fatigue

is prevented (Babcock, Pegelow, Harms, & Dempsey, 2002). These findings suggest the

respiratory muscles can get tired during maximum exercise. Research by Babcock et al. (1995)

evaluated resting subjects because they voluntarily mimicked the magnitude and duration of work

of the diaphragm seen during resistance training. They noted that fatigue did not occur until the

work of the diaphragm increased to double the work required during maximum exercise. This

would indicate that the diaphragm has to compete with the locomotor muscles for the cardiac

output available during strenuous intensity exercise, leaving the diaphragm with inadequate

transport of O2, thus creating a state of fatigue (Miller et al., 2006). This state of fatigue likely

activates metaboreflex from within the inspiration and expiratory muscles, which increases the

outflow of sympathetic vasoconstrictors, leading to redistribution of cardiac output (Harms,

McClaran, et al., 1998).

There is a complex mechanical effect of intra-thoracic and intra-abdominal pressure on

stroke volume and cardiac output with respiratory muscle fatigue (Forster et al., 2012). EFL is

accompanied by high expiratory pressure, which can approach or exceed the critical closure

pressure of the airway with exercise, which can result in increased left ventricular afterload and

reduced stroke volume (Miller, Pegelow, Jacques, & Dempsey, 2005). If inspiration is achieved

by diaphragm contraction alone, then the increase in intra-abdominal pressure generated by

downward movement of the diaphragm inhibits the return of the exercised lower limb veins

(Forster et al., 2012). Miller et al. (2005) showed that this reduced venous return recovered during

expiration with little net effect on reduced total venous return. As previously reviewed, during

strenuous sustained exercise, respiratory muscle blood flow can consume 8–10% VO2max and

cardiac output in untrained individuals and up to 14–16% VO2 and cardiac output in highly

trained individuals, thus affecting blood flow for working limb muscles (Aaron et al., 1992;

Harms, McClaran, et al., 1998; McClaran, Harms, Pegelow, & Dempsey, 1998).

Harms et al. (1998) set out to test the effect of respiratory muscle fatigue on sympathetic

outflow vs. training leg blood flow by altering respiratory work during high-intensity cycling

exercise. They use resistive loading and unloading of PAV from respiratory muscles to manipulate

respiratory work. Their results showed that exposure to the respiratory muscles in a filled state

resulted in reflex vasoconstriction that reduced blood flow to the exercising limb.

Conversely, when the respiratory muscles are dismantled with PAV, a state of increased blood

flow (dilation) exists. This change in limb blood flow indicates a competitive relationship between

the motor muscles and the respiratory muscles for limited cardiac output (Guenette & Sheel,

2007). Research on fatigue time (performance) using the same respiratory muscle loading and

unloading as discussed above shows that loading through resistive devices results in a decrease in

time to fatigue and unloading by

PAV increases time to fatigue by an average of ±14-15% (Harms et al., 2000). These results

suggest that the improved performance (time to fatigue) effect can be explained by reduced

perception of secondary dyspnea to reduced respiratory muscle work (Miller et al., 2006).

The respiratory system has to face many challenges during exercise. The most prominent

challenge is the mechanical work of the respiratory muscles due to the need for lung ventilation

at rest and during exercise and the capacity of the intra-thoracic airways to maintain patency that

allows an increase in flow rate during active expiration. During exercise, an increase in VE with

progressive exercise to fatigue creates a disproportionate increase in mechanical work (as listed

above), resulting in an increase in the cost of O2 breathing. The increased O2 cost of mechanical

work to achieve an increase in VE during strenuous continuous exercise creates competition for

cardiac output, thus affecting blood flow for the working limb muscles and, thus, causing fatigue

in both muscle groups (respiratory muscles and working skeletal leg muscles). Can exercise

performance be improved if the challenges placed on the respiratory system are reduced by

changing the pre-workout conditions of the same respiratory system?

1.3 Exercise and Its Effects on Lung Function

The second described challenge facing the respiratory system during intense exercise is

the ability of the bronchial airways (intra-thoracic) to maintain patency to allow for an increase in

flow rate during active expiration often seen with high-intensity exercise. As discussed earlier,

during high-intensity exercise, the bronchial airways sometimes present significant limitations on

expiratory flow, leading to dynamic hyperinflation, increased respiratory muscle work, and

limitations of VE (Forster et al., 2012). The challenge of maintaining this airway patency can be

assessed using a variety of breathing maneuvers, which will be reviewed here.

Spirometry is a simple method of assessing lung function by measuring the volume of air

a subject can exhale from the lungs after maximum inspiration. It is often used to diagnose

individuals with Chronic Obstructive Pulmonary Disease (COPD) and is the best way to detect

airway obstruction (Ruppel & Enright, 2012; "Spirometry for Healthcare Providers," 2010).

Specific measures derived from spirometry (directly and indirectly) include forced vital capacity

(FVC), slow vital capacity (SVC), forced expiratory volume in one second (FEV₁), FEV₁/FVC

ratio, forced expiratory flow of 25%, 50%, 75%, 25-75% (FEF 25%, FEF 50%, FEF 75%, and

FEF 25-75%), peak expiratory flow (PEF), and peak expiratory flow (PIF) (Ruppel & Enright,

2012). Another measure that is often performed after spirometry is maximum voluntary ventilation

(MVV), which can be used to obtain respiratory reserve values during maximum exercise testing

(Bender & Martin, 1985; Hill, Jacoby, & Farber, 1991; Johnson, Weisman, Zeballos, & Beck,

1999). Several other measures use different devices to assess maximum expiratory pressure (MIP

or PImax), and maximum expiratory pressure (MEP or PEmax) (Coast et al., 1999; Haverkamp,

Metelits, Hartnett, Olsson, & Coast, 2001). More difficult measurements due to the nature and

thickness of the equipment required are the determination of total lung capacity (TLC), residual

volume (RV), residual capacity fraction (FRC), and expiratory reserve volume (ERV) (Chapman,

Allen, & Romet, 1990; Ruppel & Enright, 2012).

Recent studies have used many of these measures separately or in various combinations to assess

respiratory muscle weakness and EFL.

The most commonly used spirometry values for the assessment of respiratory muscle

weakness/fatigue and EFL are the FVC and FEV₁ measures (Coast et al., 1999; Haverkamp et al.,

2001; Hill et al., 1991; Mahler & Loke, 1981; O'Kroy, Loy, & Coast, 1992). The second most

commonly used measures are MIP and MEP (Coast et al., 1999;

Haverkamp et al., 2001; Hill et al., 1991; O'Kroy et al., 1992; Ozkaplan, Rhodes, Sheel, &

Taunton, 2005). Some studies used MVV, TLC, RV, and ERV to assess EFL and possible

respiratory muscle fatigue (Bender & Martin, 1985; Cordain, Rode, Gothhall, & Tucker, 1994;

Nourry, Deruelle, et al., 2005a).

Haverkamp et al. (2001) studied the effect of expiratory muscle fatigue on lung function

in eight (seven men and one woman) healthy human subjects exposed to expiratory fatigue (EF)

trials (loaded respiratory protocols). Measurements of recovery before and after the experiment

(0, 5, 10, and 15 minutes) compared to the control experiment (CT). The findings suggest MEP is

the only measure to look at significant changes between the EF trial before/after and CT that

remain unchanged. These findings are not surprising because the termination of the EF trial

occurred when the MEP score fell below 80% of the pretrial value. It also seems plausible that

the EF trial does not have a significant intensity or duration (the average time for the end of the

trial is seven minutes) to induce a change in expiratory flow.

Hill et al. (1991) studied a group of triathlons to see what measures of lung function change

during endurance triathlons. Pulmonary function is acquired after each event, after the event is

over, and with one day of recovery. Twelve male subjects completed a 3.8 km swim, 180 km

cycling, and 42 km run with an average completion time of 12 hours 45-

±90 minutes. After the completion of the triathlon, a significant decrease from baseline was noted

in FVC (7.1%), FEV₁ (8.4%), FEF 50% (18.6%), FEF 25-75% (15.2%), but not

changes in MVV or other FEF measures, ratios, and/or PEFs. PI max did not decrease after

swimming, but decreased significantly after cycling (26%). That reduction continued after the run,

but the PE max did not show a significant decrease every time. FEV₁ was the only one that was still

considered significant in the morning after (proximally, 12 hours). These results show

The duration (>12 hours) of exercise is an important variable that reflects a decrease in some

measures of lung function. It remains to be determined at what time interval these variables return

to the baseline and the alleged cause of the decline.

Mahler and Loke (1981) studied lung function in fifteen ultramarathon runners before and

after (10 to 15 minutes and 2.5 hours) of 80.6-100 km (50 to 62.2 miles) road races with an average

running time of 7 hours and 42 minutes (within 80.6 km). The results revealed significant post-

race reductions in FVC (12.4%), FEV₁ (9.5%), FEF 50% (28.4%), PEF (13.7%) with improved

values after 2.5 hours of recovery. The authors believe there is an obstructive component of the

airway (due to a reduction in flow rate) and a component of respiratory muscle fatigue (due to

recovery after rest and food). This result is similar to the results obtained by Hill et al. (1991)

which support the value of exercise duration that results in a decrease in the size of lung function.

However, the study showed a return to baseline within 2.5 hours of recovery.

O'Kroy et al. (1992) examined the function of pulmonay exercise before and after (5, 10,

30 minutes) of nine (seven men and two women) active post-workout runners at three different

intensities and durations on a treadmill. The aim of this study was to determine which intensity

and duration induced changes in FVC and whether these changes could be associated with

respiratory muscle fatigue. The intensity and duration protocols are as follows: 1) a stratified

maximum test until fatigue (duration 7-14 minutes); 2) a seven-minute test at 90%VO2max; and 3) a

30-minute test at 60% VO2max. The MEP measure was close to significance at 10 minutes posttest

with no observed difference between intensity and MIP indicating no difference between time or

intensity. FVC differed between times but not intensity and decreased at five and ten minutes

compared to pre-values. FEV₁ is significantly reduced at five and ten

minutes compared to pre-values across intensities. The authors feel the data suggest a combination

of exercise duration and intensity may be necessary to obtain changes in lung function after

exercise and that expiratory muscle fatigue may be a factor leading to a decrease in FVC.

Something worth noting (not mentioned in the article) is that FVC and FEV₁ increased (close to

significance) for 30 minutes, 60% of the VO2max intensity protocol (from Figure 1) at 30 min

posttest, indicating the likelihood of aiway dialing occurring.

Coast et al. (1999) examined the effects of a maximal exercise trial (progressive maximum-

cycle ergometer test) and a voluntary isocapnic hyperpnea (VIH) trial (mimicking respiratory

frequency and depth at maximal exercise) on lung function before and after the trial (0, 5, 10, 15

minutes) from eleven (six men and five women) healthy subjects. A significant decrease in FVC

(7%) was observed immediately after the trial, and MIP (15%) remained reduced for 15 minutes

post-trial. MEP and FEV₁ did not change with the exercise trial and all four measures did not

change in the VIH trial. The authors suggest data suggest lung function and respiratory muscle

strength may be altered after exercise but not by similar VIH trials. They further suggest the effect

of exercise on lung function is independent of the work of the respiratory muscles performed.

Ozkaplan et al. (2005) studied the relationship between respiratory muscle fatigue and

recovery (1, 2, 3, 4, 5, 10, and 15 minutes) using post-workout MIP for VO2max in moderately

trained men (18) and women (16). MIP decreased significantly in males (16%) and females (15%)

from pre-data and remained reduced in both sexes during the 15-minute recovery. The authors

concluded that inspirational muscle fatigue after maximum exercise showed that recovery patterns

were the same in men and women. The authors may use other measures to assess respiratory

muscle fatigue such as FVC, FEV₁ and

PEF. It will also be interesting to see if this measure of lung function will tend to be the same as MIP.

Cordain et al. (1987) examined the effects of long-term exercise on respiratory muscle

strength assessed by pulmonary function data in 101 male runners (at least one year and frequency

of three or more days per week) aged 16-58 years. The results revealed that the runners showed a

much lower PE max and a much higher RV than the predicted values for height and age matching

normal subjects. No other action shows significance. The authors believe that frequent consistent

running can lead to an increase in non-pathological RV due to decreased expiratory muscle

strength.

Bender and Martin (1984) hypothesized that the ability to ventilate optimally decreases

during and after strenuous exercise. To evaluate this, they examined the size of the MVV (in 60

seconds) during the last minute and post-thorough treadmill training of 17 subjects (14 men and 3

women) subjects (8 recreational athletes and 8 competitive runners). Each experiment lasted for

three to ten minutes or 60 minutes of over-the-top exercise. The findings showed that the duration

of the three- to ten-minute workout failed to show a change in MVV. However, 60-minute

workouts showed much lower MVV values at the last minute and during recovery intervals of five

and ten. Eight non-runners and eight runners showed lower MVV values at just ten minutes of

recovery. The authors suggest the capacity for maximum ventilation decreases only in long,

thorough exercise and the most pronounced decline in non-runners.

Nourry et al. (2005) studied ventilation constraints in thirteen (nine males and four

females) aerobically trained (TR) and eleven (seven males and four females) untrained

prepubescent children (UT) by measuring the maximum volume-flow loop (MFVL) at rest and

exercise flow volume loop (EFVL) (plotted in MFVL) during the progressive to fatigue exercise

test (8 to 10 minutes duration). The results showed that TR had a higher FVC and maximum

expiratory flow than UT. In addition, TR reported higher VE, ERV/FVC and dyspnea associated

with IRV/FVC respiratory reserve and lower O2 saturation (SaO2) values at peak power compared

to UT. The authors conclude that due to the higher level of VE, TR subjects have higher ventilation

constraints than UTs.

The ability of the bronchial (intra-thoracic) airways to maintain patency, allowing for an

increase in flow rate during active expiration, is a major challenge of the respiratory system when

the need for increased VE is required (often seen with intensive exercise). Challenges in the

bronchial airways with intense exercise sometimes present significant limitations on expiratory

flow, leading to dynamic hyperinflation, increased respiratory muscle work, and limitations of VE

(Forster dkk., 2012). Spirometry and other measures can be used to assess the airway before,

during, and after exercise. Regardless of the techniques used to measure the ability to maintain

airway patency, most studies suggest that there are limitations when the duration and intensity of

exercise are sufficient to create dynamic hyperinflation (caused by EFL) and/or respiratory muscle

fatigue (also possible due to EFL) in men and women equally (Ozkaplan dkk., 2005). This

limitation is supported by data by Cordain et al. (1987), suggesting that frequent and consistent

running can lead to a non-pathological increase in RV (dynamic hyperinflation / EFL), and this

increase may be due to a decrease in expiratory muscle strength (respiratory muscle fatigue). It is

also worth noting that studies measuring increased ventilation in the absence of exercise as shown

in the VIH trial showed the effect of exercise on lung function was independent of the work of the

respiratory muscles performed (Pantai et al., 1999). Finally, when comparing these limitations in

trained vs. untrained individuals, research shows that due to

from higher levels of VE, trained subjects present higher ventilation constraints than untrained

subjects (Nourry, Deruelle, dkk., 2005a).

1.4 Expiratory Flow Limitations

Ventilation restriction exercises occur when the ventilation output (VE) is close to or

matches the ventilation capacity (Babb, 2013). EFL during training has been shown in men

(Johnson, Saupe, & Dempsey, 1992) (Hue, Boussana, Le Gallais, & Prefaut, 2003) and women

(McClaran et al., 1998). Currently, there is no agreed way to measure ventilation capacity, but

some suggest overlaying the tidal flow volume loop of the exercise within the maximum resting

volume-flow loop (Babb, 2013). However, Babb (2013) points out that simply making a

comparison of the volume loop of the tidal flow of the exercise with the maximum volume-flow

loop measured in the mouth to see the EFL scale may not tell the whole story. Others suggest the

use of FVC, FEV₁, PEF, FEF 50% and RV for a more effective way of judging (Beck, Hyatt,

Mpougas, & Scanlon, 1999; Buono et al., 1981; Cordain, Glycan, Latin, Tucker, & Stager, 1987;

Cordain et al., 1994). Regardless of its size, approaching the EFL can initiate a series of changes

that can play a crucial role in creating ventilation limitations during training and sports intolerance

(Babb, 2013).

A significant cause of EFL in many endurance athletes during strenuous sports is

hyperinflation and an increase in their end-expiratory lung volume (Guenette, Witt, McKenzie,

Road, & Sheel, 2007; Johnson et al., 1992; McClaran et al., 1998). Most of these athletes have

normal airways and normal age-predicted maximum flow volume data, but their high peak training

capacity creates extreme demands on ventilation and flow rate, often resulting in EFL,

hyperinflation, and reduced inspiration capacity (Dempsey, McKenzie, Haverkamp, & Eldridge,

2008). Some of the complications with hyperinflation in the lungs are as follows: 1)

causes decreased dynamic lung compliance, increases elastic respiratory work, thereby limiting

the hyper-ventilation response to strenuous intense exercise, thereby contributing to arterial

hypoxemia and worsening of dyspnea; 2) impaired cardiac output and stroke volume caused by

increased afterload placed on the left ventricle with increased intra-pleural pressure of positive

expiration with this pressure often exceeding the critical closure pressure of the road breath; 3)

tidal volume plateaus at lower VE cause tachypnea and 4) inspirational muscle fatigue develops

because muscles function shorter than their optimal length with faster short circuit speeds

operating at the dynamic capacity limits of their force generation (Babb, Viggiano, Hurley, Staats,

& Rodarte, 1991; Dempsey et al., 2008; Guenette et al., 2007; Johnson et al., 1992; McClaran et

al., 1998; Mota et al., 1999). EFL and the cascade of events outlined are more likely to occur in

younger women (due to smaller lungs) (McClaran et al., 1998) and older endurance athletes (loss

of elastic retrograde with normal aging) than in younger men (Guenette et al., 2007). EFL in

women can be explained largely by anatomical factors that affect the capacity to produce flow and

volume during exercise as opposed to fitness-related factors (Dominelli, Guenette, Wilkie, Foster,

& Sheel, 2011). For a more complete review of the role and consequences of EFL during and after

training, one should look at the reviews in Babb (2013) and Dempsey et al. (2008).

Guenette et al. (2007) compared respiratory mechanisms (EFL, end-expiratory lung

volume, end-inspired lung volume and respiratory work) in endurance-trained athletes (eighth

men and tenth women) during cycling exercise. EFL measurements are derived from the

application of negative expiratory pressure in the mouth as described in Mota et al. (1999). The

final lung volume of expiration and the volume of the lungs of the final inspiration are achieved

through the maneuver of the capacity of inspiration. Respiratory work is integrated by plotting the

difference between the esophagus and

airway opening pressure (trans-pulmonary pressure) against volume. EFL's limitations were seen

in nine women and three men in the final stages of training. Women have higher final expiratory

lung volume, final inspiration lung volume, and respiratory work (twice) than men at maximum

exercise. The authors believe that EFL, final expiratory lung volume, and final inspiration lung

volume may be more commonly experienced in women than in men at maximal exercise because

smaller lung volume and airway diameter are seen in women, leading to increased respiratory

work. These findings collectively show that females use most of their ventilation reserves at

higher respiratory costs than males.

Bruno et al. (1981) set out to determine and track the effects of acute exercise combat

(continuous treadmill until fatigue) on RV and TLC (determined by closed-circuit O2 dilution

methods) and other pulmonary function measures during 24-hour exercise recovery. They tested

twelve males before and after exercise (5, 15, 30 minutes, 1, 2, and 24 hours). The results showed

that RV increased significantly by 20.8%, 16.8%, and 12.0%, respectively, at 5, 15, and 30 minutes

of recovery from exercise. TLC showed an increase in significance on five-minute (2.7%) and 15-

minute recoveries. Interestingly, FVC and FEV₁ did not change after training. It is possible that

the cooling protocol (3 miles per hour, 0% grade for 5 minutes) allows these values to be close to

the resting values and not show any significance. However, looking at the data (and something not

mentioned by the authors), FEF measures of 25-75% (moderate to small airways) showed a 5.8%

increase at five and 7.6% 15-minute recoveries, respectively. Could this increase reflect the period

of refractory that occurred? This is not the goal identified from this study, but it should raise

reasonable questions in the face of RV and TLC improvements if these improvements reflect EFL.

Cordain et al. (1994) evaluated the mechanisms that may be responsible for the acute

increase in RV that is often observed after exercise in 12 men who performed two exercise attacks

on separate days. Subjects performed one exercise for maximum heart rate and one to 85% of

maximum heart rate for 20 minutes. Lung function measures were obtained before and at 5, 15,

30, 60, and 120 minutes after exercise. Results showed significant RV improvements at 5, 15, and

30 minutes after maximum exercise and at 5 and 30 minutes after suboptimal exercise. Maximum

practice shows greater changes in the RV as seen in the submax practice battle.

Decreases were noted in PEmax and FVC, possibly due to a decrease in expiratory muscle strength,

but FEV₁ and FEF 75-85% did not change or increase. The authors address this by claiming, a 75-

85% increase in FEV₁ and FEF indicates little or no small airway compression by a shift in fluid

volume in the lungs, as cited in their review of the work. Again interesting to note this may be the

result of refractories in the airways after exercise.

Babb et al. (1991) attempted to determine the effect of mild to moderate airflow restriction

on exercise tolerance and end-expiratory lung volume by examining nine control subjects with

normal lung function and twelve patients with mild to moderate airflow limitations during

progressive cycle exercise. The data revealed that the patients had a reduced VO2max (69% of

the predicted) compared to the control (104% of the predicted). The final expiratory lung volume

was similar at rest in both groups (53% TLC), but the patients' maximum exercise value decreased

to 45% TLC, and the control increased to 58% TLC. The authors propose that the volume of the

lungs of the end of expiration correlates significantly with the values of FEV₁ and VO2max and

this relationship suggests there is a ventilation component to exercise capacity but that an increase

in the volume of the lungs of the end of the expiratory may have an impact on cardiovascular

function during exercise. In the discussion, the authors suggest an abnormal ventilation response

generated in patients

Because the limited value of expiratory flow reserves leads to a reduction in their daily living

activities, thus creating a state of deconditioning. What's interesting to note is that normal controls

also show some EFL at maximum exercise while still reaching their maximum heart rate

prediction.

Hue et al. (2003) aimed to investigate lung function (ten minutes before and ten minutes

after a cycling trial) and compare it to that seen in the cycle succession/run as is often done by

triathlons. Thirteen young men participated in three training trials: 1) 30 minutes of constant speed

cycling followed by 20 minutes of constant speed running; 2) 30 minutes constant speed cycling

control; and 3) 20 minutes constant speed control running. Results for lung volume and capacity

for cycle-only trials showed significant improvements in RV, FRC, and RV/TLC ratios, but no

significance was found in lung volume or flow with cycles/runs or run-only trials. Based on these

findings, the authors suggest that cycling by itself seems to increase changes in post-workout lung

volume that can lead to changes in respiratory muscles (fatigue), and that these changes may be

the result of a squatting cycling position. Another study showed cycling induced a greater decrease

in respiratory muscle endurance than running (Boussana dkk., 2003; Boussana dkk., 2001; Hill et

al., 1991). Looking deeper into the data, the FEF values showed a slight improvement for the pre-

scores for cycles/runs and the run-only trials, which may indicate some airway refractories.

A series of events created by hyperinflation in the lungs can lead to changes in dynamic

lung compliance that increase the elastic work of breathing, sacrifice cardiac output and stroke

volume, lead to increased tachypnea, and inspiratory muscle fatigue, limiting the dynamic

capacity to generate force (Babb et al., 1991; Dempsey et al., 2008; Guenette & Sheel, 2007;

Johnson et al., 1992; McClaran et al., 1998). Young women (because they are smaller

lungs and airway diameter) and older endurance athletes (loss of elastic retrograde with normal

aging) experienced a higher incidence of EFL than younger men. Females make use of most of

their ventilation reserves, thereby significantly increasing their respiratory costs compared to

males (Guenette et al., 2007). By paying attention to the exercise modalities, it appears that cycling

exercise by itself increases the volume of the lungs post-workout (RV increase) which can lead to

changes in the respiratory muscles (fatigue), and these changes may be caused by squatting

cycling versus running upright (Boussana dkk., 2001; Hill et al., 1991; Hue et al., 2003). A study

by Babb et al. (1991) showed that the volume of the lungs at the end of expiration was significantly

correlated with the values of FEV₁ and VO2max, so the relationship between the ventilation

component and the exercise capacity and the increase in lung volume at the end of the expiratory

lung could have an impact on cardiovascular function during exercise. The authors also suggest

this may lead to a state of deconditioning (reduced activities of daily living) for individuals with

abnormal ventilation responses due to limited expiratory flow reserve values. In this same study,

normal control subjects also showed some EFL at maximum exercise while still reaching the

maximum predicted heart rate. Three of the five studies reviewed here, showed the possibility of

airway refractories seen in their subjects. Bruno et al. (1981) showed a 25-75% increase in FEF

size at five (5.8%) and 15 min (7.6%) recoveries, indicating some increase in expiratory flow in

the face of increased RV and TLC values. Cordain et al. (1994) found elevation or no change in

FEV₁ and FEF of 75-85% indicating little or no airway compression from fluid shifts in the lungs.

And finally, a deeper review of Hue et al. (2003) of individual data revealed a slight increase in

FEF size compared to pretrial data for cycles/runs and trials.

1.5 Sports-induced bronchoconstriction

Another area of relevance to this review is exercise-induced bronchoconstriction (EIB).

EIB is a temporary narrowing of the lower airway during and after exercise with the presence or

absence of clinically recognized asthma (Rundell, Spiering, Judelson, & Wilson, 2003; Weiler et

al., 2010). EIB is the preferred term over exercise-induced asthma (EIA) because not all

individuals with EIB suffer from asthma. Also, in asthmatics, exercise is not an inducer but a

trigger for bronchoconstriction (Brown, Howard, Khan, & Carmody, 2012). The mechanism of

EIB is based on two main theories, the "osmotic theory" and the "thermal theory." Osmotic theory

suggests a high level of ventilation during exercise that leads to excessive water loss for airway

surface fluids that alter the osmolality of the airway cells of the inhabitants leading to the release

of inflammatory mediators. Thermal theory states exercise causes airway cooling, and rapid

reheating after stopping exercise leads to reactive hyperemia, edema, and obstruction (Rundell et

al., 2003).

EIB is characterized as ≥10 or ≥15% of the reduction from FEV₁ before to after exercise

and is generally seen in three to fifteen minutes of recovery from exercise (Gothhall, 2002; Rundell

et al., 2003). EIB is very common in people with asthma (80-90%) and is seen more often in

individuals with more severe cases and in poorly controlled asthma compared to only about 12-

19% of the general population (Brown et al., 2012; Gothall, 2002). About 40-50% of individuals

with asthma may show a "refractory period", (reduced bronchoconstriction to exercise if done with

the first 2-4 hours of exercise) (Gothhall, 2002; Mahler, 1993; Randolph, 1997). The use of heating

to induce refractory periods to limit the severity of EIB may certainly have benefits for reducing

symptoms, reducing drug use, and improving exercise performance (Stickland, Rowe, Spooner,

Vandermeer, & Dryden, 2012). The EIB in elite athletes is generally higher than in the general

population and varies based on

type of exercise, maximum level of exercise and specific environmental conditions (Brown et

al., 2012). Khan (2012) displays the prevalence (percentage) of asthma incidence in the

Olympic Games as cited in (Weiler, Layton, & Hunt, 1998; Weiler & Ryan, 2000) as follows:

(60.7%) a combination of Nordic, cross-country, and short-track; (50%) cycling and mountain

biking; (29.6%) synchronized swimming and swimming; (24%) canoes/kayaks, paddle and

sailing/cruises, and alpine, long trails, figure skating, snowboarding, and curling. These athletes

indicated through questionnaires, "They have been told they have asthma" or "they have been

taking asthma medication at some point."

Rundell et al. (2003) set out to determine if bronchoconstriction occurs during an interval-

type simulated cross-country ski race and whether there is a refractory period when the second

attack of an interval-type exercise begins within 20 minutes of completing the first session. They

examined airway and refractory responses during a cross-country skiing time trial of about 42

minutes which was preceded by a six- to nine-minute 2.5km high-intensity warm-up ski. Eighteen

(thirteen men and five women) elite cross-country skiers completed seven consecutive 2.5km laps

and had spirometry measured before and at 5, 10 and 15 minutes after loop 1 and 20 seconds after

loops 2-6 and then serially up to 15 minutes after loop 7. Nine subjects showed a ≥10% reduction

from baseline in their FEV₁ (EIB+). Of the nine, five showed a significant decrease after loop 1,

and the other four dropped significantly between loops 2-7 with one EIB+ subject showing

significant refractory. The authors concluded EIB occurred in athletes during prolonged training

with a variable bronchial hyper-responsive onset that could affect performance. The lack of

significant refractory in their cohort is consistent with exercise bronchoconstriction dysfunction

and is different from asthma. Lack of this research

Support for airway refractory may be due to the limited time of 15 minutes for recovery from

exercise rounds 1 to exercise rounds 2-7 and environmental exposure from exercise.

The mechanism of EIB exists in two main theories, the osmotic theory (high levels of VE

cause water loss in the airway) and the thermal theory (cooling and reheating of the airways leads

to airway reactive hyperemia, edema, and obstruction). One or both of these theories may

contribute to EIB (narrowing of the lower airways during and after exercise in the presence or

absence of clinically recognized asthma). The prevalence of EIB is common in 80-90% of people

with asthma, 12-19% of the general population and in elite athletes with a degree of severity,

depending on the type of sport, maximum level of exercise, and certain environmental conditions

can vary by up to 24-60%. It is also suggested that about 40-50% of individuals with asthma may

exhibit a refractory period with warm-up before exercise. In contrast, Rundell et al. (2003) suggest

EIB occurs in athletes (different from those seen in asthmatics) during prolonged exercise with a

variable bronchial hyper-responsive onset that can affect performance with only one in nine elite

cross-country skiers exhibiting significant refractory. Lack of support for airway refractories may

be affected by the limited time between the first trial (considered a warm-up exercise) and

successive attempts (15 minutes) and/or environmental exposure.

The EIB will be reviewed more fully in part III Respiratory System Warming.

1.6 Breathing Muscle Exercises

Respiratory muscle training (RMT) can be divided into two very different types, namely

respiratory muscle strength training (resistive or threshold) and endurance training (hyperpnea).

These types have been used to improve the endurance performance of healthy, sick, and athletic

individuals (Beckerman, Magadle, Weiner, & Weiner, 2005; Enright & Unnithan, 2011; Griffiths

& McConnell, 2007; Hanel & Secher, 1991; Hostettler et al., 2012; Leddy et al.,

2007; Sonetti, Wetter, Pegelow, & Dempsey, 2001; Uemura, Lundgren, Ray, & Pendergast, 2012;

Weiner, Azgad, Ganam, & Weiner, 1992). Most studies on RMT propose improved endurance

training performance in both healthy and sick individuals with less improvement seen in very fit

individuals. The most common types, respiratory muscle strength training and respiratory muscle

endurance training, both have the same effect on performance improvement (Hostettler et al.,

2012). Respiratory muscle strength training is divided into two types: inspirational flow and

expiratory resistive load or inspirational and expiratory pressure threshold weight training (A.K.

McConnell & Romer, 2004). In the inspirational and expiratory flow resistive load training model,

the individual is inspired or expires through a variable-diameter bore device, and the smaller the

hole size, the greater the work required for each constant flow that delivers through the device.

(Hostettler et al., 2012). In the inspiration/expiratory pressure threshold load training model,

individuals create negative stress by breathing through the device while trying to cope with the

threshold load set to initiate inspiration or expire. Respiratory muscle endurance training, also

known as Voluntary Isocapnic Hyperpnea (VIH), requires individuals to maintain a high level of

target ventilation for a duration of up to 30 minutes (Coast et al., 1999; A. K. McConnell & Romer,

2004). The involvement of a high level of hyperventilation for a long time with respiratory muscle

endurance training makes the observed effects on the inspiration or expiratory muscles impossible

to isolate (A. McConnell, 2009). The combined effects of inspirational and expiratory muscle

training are suggested to be superior in improving performance (Hostettler et al., 2012). When

using inspirational and expiratory muscle exercises, it is much easier to separate, thus providing a

better indication of the role of each muscle group in performance outcomes (A. McConnell, 2009).

A study to examine the effects of cross-experimentation between inspirational and expiratory

muscle training did not find a significant expiratory effect

muscle training on performance alone or supplemented with inspirational muscle training

(Griffiths & McConnell, 2007). It is also suggested that adding expiratory muscle exercises to

inspirational muscle exercises during the same breath cycle may interfere with the inspiratory

muscle response to inspirational muscle exercises (A. McConnell, 2009).

Non-traditional Training Program- Beckerman et al. (2005) set out to assess the long-term

effects of inspirational muscle training on inspirational muscle strength, exercise capacity,

dyspnea perception, quality of life, and utilization of medical care in patients with COPD. They

evaluated 42 COPD patients with FEV₁ <50% of the predicted (before and at 3, 6, 9, and 12 months

during the training program) and randomly assigned them to a training group (21 subjects) who

performed inspiration muscle training for 1 year or a control group (21 subjects) who received

training with a very light load. The threshold intensity starts at 15% of the PImax for the first week

then progresses by 5-10% daily until it reaches 60%. This PI max value is maintained from the first

month to the sixth month of training. The parameters of the subjects assessed were FVC, FEV₁,

six-minute walking test, PImax, perception of shortness of breath, and health-related quality of life.

The data showed a significant increase in inspirational muscle strength (PImax) at the end of the

third month of training as well as an increase in the six-minute walking test. A significant

improvement in quality of life was seen at the end of the sixth month, and a significant decrease

in the perception of dyspnea at the end of the ninth month was noted. All benefits were maintained

for 12 months, and a decrease in health care use was noted. The authors believe the data show the

long-term effects of inspirational muscle training in COPD patients improve exercise capacity

measures, quality of life, and perception of dyspnea, as well as reduce health care utilization.

Another interesting observation is that there is no significant spirometry value

changed over the duration of the study, and once the measure increased to a significant degree,

there was very little additional improvement seen from the continuous improvement in training

progression.

Weiner et al. (1992) examined adults with bronchial asthma by comparing specific

inspirational muscle training and sham training (placebo) on inspiratory muscle

strength/endurance, asthma symptoms, health care care for asthma, missed school or workdays,

and medication use (inhaled β2-agonists). Thirty people with moderate to severe asthma were

divided into several groups. One group of 15 individuals received specific inspirational muscle

training, and the other 15 individuals were given control sham training. Both groups practiced five

times a week for 30 minutes for six months. The threshold intensity starts at 15% ofthe PI max and

progresses to 60% and then 80% during the last two months of training. Results showed a

significant increase in inspirational muscle strength as evaluated by PImax in RVs and a significant

improvement in respiratory muscle endurance as expressed by the association between PmaxPeak

and PImax in subjects in a specific inspirational muscle training group but not a sham training group.

The specific inspirational muscle training group showed significant improvements compared to

baseline data for asthma symptoms (nocturnal asthma), morning shortsightedness, daytime

asthma, and cough, inhaled β2-agonist use, number of health care days or visits, and number of

missed sick days due to asthma. The authors concluded a special six-month inspirational muscle

training program improved respiratory muscle strength and endurance, as well as asthma-related

symptoms, health care use, drug use, and job and school time loss.

Spirometry data from before and after training showed small but significant improvements in

FVC and FEV₁ in the specific inspirational muscle training group compared to the matching

(sham) control group. Five people can stop taking oral/IM corticosteroids

The drugs during the specific inspirational muscle training group were compared to just one in the

sham control group.

Hanel and Secher (1991) studied the effects of 10-minute inspirational muscle training

twice a day for 27.5 days on ten subjects in the training group (about 50% of the maximum

intensity of the PI) and ten subjects in the sham training group. They obtained pre- and post-

training data on maximum ventilation, maximum oxygen uptake (VO2max), maximum respiratory

rate during training, running distance in 12 minutes on the track, PEF rest, FVC, FEV₁, PImax and

alveolar oxygen tension (pAO2). Results from the inspirational muscle training group showed a

significant increase in PI max, a slight but significant decrease in respiratory frequency. All other

measures that came from the inspirational muscle training group were similar to the sham control

group. The authors suggest that inspirational muscle training resulted in a significant increase in

PI max but had no effect on VO2max, 12-minute running distance, resting PEF, FVC, FEV₁, and

alveolar oxygen tension (pAO2). A possible limitation of this study is the parameters of the

training protocol, which were twice daily for 10 minutes and a total of 27.5 days and about 50%

of the PI max intensity compared to the previously reviewed study by Weiner et al. (1992). In this study,

the authors trained their asthma patients five times a week for 30 minutes for six months with

intensities varying up to 80% ofthe PI max. Of course, the comparison of the respiratory system of

healthy subjects with the respiratory system of asthma patients is not the same, but the increase in

the parameters of the training protocol (time, duration, and intensity) may have altered the results

seen in the study of Hanel and Secher (1991).

Griffiths and McConnell (2006) investigated the effects of four weeks of inspiration

muscle training and/or expiratory muscle training and the effects of a subsequent six-week trial of

combined inspiration muscle training and expiratory muscle training on club-level rowers on

rowing performance. They studied seventeen male rowers before and after training with ten doing

inspirational muscle exercises and seven doing expiratory muscle exercises. After the initial four

weeks of the two training protocols (about 50% of the intensity of the PImax, and PEmax exercises ),

all subjects performed six weeks of combined inspirational and exhalation muscle exercises. The

measures evaluated at four and ten weeks were PImax, PEmax, minute ventilation, maximum flow

volume loop (PIF, PEF, FVC, FEV₁ and FEF 50%) during the stepwise paddle ergometer step test

and an all-out six-minute effort (6MAO). The results showed a significant increase in PImax of

26%, an increase in average power during (6MAO) of 2.7%, and a small decrease in heart rate of

up to about 5% in the inspirational muscle training group. The expiratory muscle training group

showed a 31% increase in PEmax at the end of the intervention, but no other significant measures

during the step test or the 6MOA test. The authors believe inspirational muscle training can

improve rowing performance, but expiratory muscle training and the combination of inspirational

and expiratory muscle training did not result in significant performance changes.

Enright and Unnithan (2011) evaluated the effects of inspirational muscle training on

varying intensities on inspirational muscle function, VC, TLC, working capacity, and power

output in forty healthy individuals. Subjects were randomly assigned to four groups. One group

was assigned to be controlled without training. The other three groups completed an eight-week

inspirational muscle training program set at 40, 60, or 80% of the sustained PI max. Training is

conducted three days a week, with 24 hours separating training days. Before and after body

composition training measurements, VC, TLC, MIP, MIP are continuous, working capacity and

power output are obtained. The results showed significant increases in MIP and SMIP at all

intensities (40, 60, and 80%), while training intensities of 60 and 80% showed significant

increases in

working capacity and power output. The 80% exercise intensity was the only group that showed

significant improvements in VC and TLC. The authors believe if substantial stress is generated

during a high-intensity inspirational muscle training program then significant improvements in

lung volume, working capacity, and power output could be seen in healthy subjects.

Uemura et al. (2012) compared two different types of respiratory muscle training on the

exercise performance of eight (four men and four women) experienced runners. The training

consisted of four weeks of resistive respiratory muscle training, twelve sessions (60% of PImax,

and PE max intensity). Followed by four-week VIH training, twelve sessions (40% of MVV/respiratory

frequency) with spirometry measures (FVC, SVC, FEV₁, MVV PImax, PEmax,), respiratory

endurance time, VO2max, walking time to voluntary fatigue at 80% VO2max, blood lactate

concentrations, and minute ventilation obtained before and about five days after each training

protocol. Changes before and after training were seen with resistive breathing muscle exercises

significantly increasing inspiration muscle strength by 23.8% and 18.7%, respectively, at rest and

post-workout running tests. VIH training significantly increased the time of respiratory endurance

to fatigue by 237.8%, SVC by 3.43%, and decreased MVV by 20%. Both breathing exercise

protocols significantly increased the duration of endurance by 17.7% for resistive breathing

muscle exercises and 45.5% for VIH training. No other measures showed significant changes in

any of the breathing training protocols. Interestingly, after the VIH training, FVC and FEV₁ did

show a slight improvement, although not seen as significant by the authors. Also important to

consider is comparing two training protocols, VIH following inspiration/expiratory muscle

training, which may have an additive effect on VIH results.

Leddy et al. (2007) examined the effects of VIH training with an intensity set at about 50%

of VC and MVV values for four weeks and 30 minutes a day on respiratory system and running

performance in twenty-two male competitive runners (fifteen in the training group and seven in

the sham control group). The measures assessed were FVC, FEV₁, MVV, MIP, MEP, VO2max,

four-mile running time, treadmill running time to fatigue at 80% VO2max, serum lactate, total

ventilation, VO2, oxygen saturation, and cardiac output before and after four weeks (after one day

and after seven days) of training days. Spirometry data and four-mile run times are measured

monthly during a three-month maintenance period. The data showed a significant improvement

seven days after MVV training (+10%), respiratory endurance (+208%), treadmill running time

(+50%), along with a reduction in four-mile running time (-4%), respiratory rate (-6%), VE (-7%),

VO2max (-6%), lactate (18%), during the treadmill running test. Of these, four-mile run times

remained above the pre-training level during a three-month maintenance period during which

reduced VIH training was recorded. The authors believe that with a seven-day break after four

weeks of intense training, the VIH training program is important to reveal the ergogenic effects

obtained with training and that gains can be maintained during the next period of reduction in the

frequency of VIH training.

Beckerman et al. (2005) and Weiner et al. (1992) examined the effects of inspirational

muscle training in individuals with respiratory tract diseases (COPD and Asthma) and found

increased exercise capacity, quality of life, asthma-related symptoms, loss of work and school

time, and perception of dyspnea, as well as decreased health care/medication use. Four studies

examined the effects of inspirational or expiratory muscle training protocols. Hanel and Secher

(1991) showed significance only in PImax, but used a limited protocol in time, duration, and

intensity. Instead, the remaining authors used inspirational muscle exercises

The protocol finds significance in a variety of measures, including performance improvements.

Griffiths and McConnell (2006) used six weeks of RMT training at 50% of PImax and PEmax, and

found inspirational muscle training was superior to expiratory muscle training in increasing

average strength (2.7%) in a six-minute all-out rowing effort. Enright and Unnithan (2011) found

an increase in performance (working capacity and power output) in their subjects at 60 and 80%

of the PI max training intensity and three days a week for eight weeks. Uemura et al. (2012) studied

inspiration/expiratory muscle training and VIH and found VIH training was superior in improving

performance (resistance running) over inspiration/expiratory muscle training (45.5% and 17.7%,

respectively), but both showed improvement. However, it should be noted that the four-week VIH

training follows the four weeks of inspiration/expiratory muscle training, thus creating an

additional effect on the VIH results. Leddy et al. (2007) also examined the VIH training protocol

on running performance and found that treadmill running time increased on the first day of post-

training (29%) and seven days post-training (50%) in four weeks of training for 30 minutes a day.

Several studies have shown significance in the measurement of lung function with increased

inspirational muscle training in FVC and FEV₁ (Weiner et al., 1992) and VC and TLC at 80%

intensity exercise (Enright & Unnithan, 2011). Due to the nature of each training protocol,

inspirational or expiratory muscle training showed significant improvements in PI max and PE max,

respectively (Griffiths & McConnell, 2007; Hanel & Secher, 1991; Uemura et al., 2012; Weiner

et al., 1992), and VIH showed increased significance in MVV (Leddy et al., 2007; Uemura et al.,

2012).

Traditional Training Programs- The beneficial effects of exercise are often seen in many

body systems with all types of exercises if done consistently, across the life span of all individuals.

Exercise can delay many of the lung changes seen with aging and

reduces other risk factors associated with chronic lung disease, although many studies are

inconsistent about the effect of exercise on lung function (Huang & Osness, 2005). Swimming

and running are just two examples of aerobic exercise that can be considered the best for

maintaining physical health and fitness and is known to have a profound effect on lung function

for many individuals (Sable, Vaidya, & Sable, 2012). Research on the effects of resistance training

on lung function (Singh, Jani, John, Singh, & Joseley, 2011) is rare, but recent pulmonary

rehabilitation guidelines recommend upper extremity resistance training in COPD patients for a

better rehabilitation program (Ries et al., 2007). The following is a review of studies on the effects

of general aerobic conditioning programs (Sable et al., 2012; Shinde et al., 2013), the impact of

high-intensity interval aerobic conditioning programs on lung function (Dunham & Harms, 2012;

Nourry, Deruelle, Guinhouya, et al., 2005) and endurance training (Singh et al., 2011).

Sable et al. (2012) examined the lung function of two different groups of athletes,

swimmers and runners to make comparisons on lung function. Thirty swimmers who trained at

least two to three kilometers per day on a regular basis compared to a matching group of thirty

middle-distance runners. Both groups were trained over the previous three years. The tidal volume

measures, FVC, FEV₁, and MVV were significantly higher in the swimming group than in the

running group. The authors believe the effects of swimming exercises affect lung volume

measurements because swimmers' respiratory muscles are required to develop greater pressure as

a consequence of immersion in water during the breathing cycle, leading to a functional

improvement of the muscles (such as the diaphragm) involved in breathing. The study sheds light

on the value of exercising the respiratory muscles as these people have been trained for the past

three years. It will be interesting to know the percentage

Prediction values for each of the groups studied and how the non-exercise control group would

change the outcome.

Shinde et al. (2013) examined the effects of aerobic exercise and yoga exercise on weight

loss and lung function before and after exercise (one year). Sixty male and female subjects (30-50

years old) with diagnosed obesity (grade I or II as calculated through BMI) were divided into two

randomly matched groups. One group was an aerobic exercise exercise group (walking, 45 to 60

minutes a day for five days a week) and the other as a yoga exercise group (various yoga exercises,

45 to 60 minutes a day for five days a week). At a one-year follow-up, the results showed

significant improvements in measures of BMI, FVC, FEV₁/FVC, and MVV in the yoga group

compared to the aerobic exercise group. The authors concluded regular yoga practice is beneficial

in weight loss and improves lung function. Of course, one can see this study as very interesting,

but an important variable to keep in mind is that yoga emphasizes that the use of breathing control

and techniques performed in various postures / poses, which, in turn, can improve lung function.

In addition, the aerobic exercise group protocol does not control the intensity of exercise, possibly

the cause of limited improvement.

Dunham and Harms (2012) set out to determine whether high-intensity interval training

(HIT) will improve respiratory muscle strength and expiratory flow rate more than aerobic

endurance (ET) training alone. Fifteen healthy subjects who were physically active were

randomly divided into either a high-intensity interval training group (eight subjects) or an aerobic

endurance training group (seven subjects). The high-intensity interval training group completed a

four-week training program three days a week, exercised on a cycle ergometer at 90% VO2max

in one-minute intervals of 90% work rate, then three minutes at 20 watts, and repeated

interval for a total of 20 minutes. The resistance training group completed the same four-week

exercise, three days a week, but trained for 45 minutes at 60-70% VO2max of the constant load

cycle. From the values assessed before, at the two weeks of training, and after the training program

was completed, both groups showed significant improvements in VO2max (about 8-10%), five-

mile time test (6.5%) HIT and (4.4%) ET. Both groups significantly increased PImax post-training

(43%) HIT and (25%) ET. The HIT group had a much higher size than the ET group. No change

was recorded in the rate of expiratory flow in either training group. The authors believe that full-

body aerobic endurance training exercises and high-intensity interval training are effective in

increasing inspirational muscle strength, with HIT offering a more time-efficient method than ET

in improving aerobic capacity and performance. It is reasonable to believe that the duration of the

program (four weeks) is the reason the training program has no more effect on lung function

values, but it is worth noting that a closer look at the PEF measure also showed an increase (28%

for HIT and 9% for ET) with both training groups from pre-training scores.

Nourry et al. (2005) investigated the effects of intermittent running, short-duration, high-

intensity training on rest and pulmonary function exercise in healthy and pre-pubertal children.

The training group consisted of three women and six men (age 9.7 years). They participated in

eight weeks of high-intensity intermittent running training and were compared to a control group

(regular physical activity) consisting of four women and five men (age 10.3 years). The training

group carried out their regular physical education at school and trained an additional two days at

their maximum aerobic speed percentage (MAS, determined through a 20m shuttle running test).

The training session (about 30 minutes of total training) consists of a ten-second warm-up at

100% MAS followed by a series of varied short exercises, four short runs, and intermittent (10-

seconds running in the range of 100-130% MAS) separated by three minutes of passive recovery.

After the eight-week training program, no changes were seen in the control group, but the training

group significantly improved FVC (7%), FEV₁ (11%), PEF (17%), FEF 50% (16%), FEF 75%

(15%), as well as, VO2max (15%), VE (16%), VT (15%). The authors suggest eight weeks of

high-intensity intermittent running training can improve resting lung function and exercise

ventilation in prepubertal children.

Singh et al. (2011) examined the effect of upper body resistance training on lung function

in 30 male smokers (aged 25-55 years). Subjects were randomly assigned to two groups. One of

them is an exercise group consisting of fifteen subjects (experimental group, EG) and a second

non-exercise control group of fifteen subjects (CG). EG exercises for four weeks, three times a

week on non-consecutive days, using upper body resistance training (five major muscle groups,

50-85% of a maximum of one rep, three sets of ten repetitions) and conventional deep breathing

exercises. CG only performs breathing exercises in conventional and remains inactive. Lung

function assessed before and after 4 weeks of training revealed significant improvements in FEV₁

(9%) and FEV₁/FVC (9%), but no change in FVC. The CG group had no significant changes

recorded, and the elimination of the direct effects of conventional breathing exercises may have

contributed to improvements in lung action. The authors concluded that a four-week upper body

endurance training program resulted in significant changes in lung function in sedentary male

smokers.

Sable et al. (2012) examined the lung function of two groups of athletes, swimmers and

runners, and found swimmers showed significantly higher lung function values than runners, a

trait that can be explained by swimmers' exposure to water immersion which increases the

pressure that the respiratory muscles fight during their aerobics

Training. Shinde et al. (2012) found regular yoga practice (> one year) compared to aerobic

exercise was beneficial in weight loss and improved lung function, which could be attributed to

the use of breathing control, and the technique was performed in a variety of postures/poses

emphasized in yoga training. It is important to note that in the aerobic exercise group, the training

protocol does not control the intensity, thus limiting the results of this group. Dunham and Harms

(2012) used two training protocols (aerobic training and HIT) and found significant improvements

in performance (VO2max and time test), as well as PI max, and PEF with both training protocols,

but the HIT group proved superior. Nourry et al. (2005) also investigated an eight-week HIT

program with significant improvement in performance (VO2max) and measures of lung function.

Finally, a study of Singh et al. (2011) using upper body endurance training to show improvement

is a measure of lung function in just four weeks. As shown here, apart from traditional aerobic

exercise, yoga, HIT, or upper body resistance training results in positive effects of lung function

and performance improvement. Something interesting to note, is that from the review of the

protocols here, protocols that challenge the respiratory system (with high ventilation requirements

or respiratory muscle work) result in the most improvements.

1.7 Respiratory System Heating

This section will review that relevant research is being conducted on how to use pre-

workout warm-ups to limit the EIB seen in individuals who may be susceptible to airway

constriction and any effects on exercise performance. As discussed earlier, the refractory period

can develop after certain warm-up protocols, thus creating a period in which further strenuous

exercise results in a much lighter EIB or no EIB (Stickland et al., 2012). The refractory period can

occur in about 40-50% of individuals who have an initial episode of EIB but then experience a

reduced response

which can last from 1-4 hours after a warm-up workout (Randolph, 1997). The mechanism leading

to the refractory period is unclear, but some suggest it may be mediated by catecholamine

depletion, increased circulation of prostaglandins, degranulation of mast cell mediators (Anderson

& Holzer, 2000), or with increased bronchial blood flow and the rate of water returning to the

airway surface (Kippelen dkk., 2012). The idea of a mechanism to consistently create refractory

periods in individuals with EIB or non-EIB individuals who engage in strenuous intensity exercise

that may be susceptible to EFL is particularly exciting because it can improve fewer symptoms,

decrease drug use, and improve exercise performance (Stickland dkk., 2012).

Research on the effects of pre-workout warm-up can be divided into three areas based on

the type of warm-up protocol studied (interval, continuous high intensity, and continuous low

intensity). Several studies examine different types of warming strategies/protocols. Of the interval

type protocols, four studies will be reviewed (de Bisschop, Guenard, Desnot, & Vergeret, 1999;

McKenzie, McLuckie, & Stirling, 1994; Mickleborough, Lindley, & Turner, 2007; Zach, Schnall,

& Landau, 1980); for a sustained high-intensity protocol, two studies will be reviewed (Reiff,

Choudry, Pride, & Ind, 1989; Zach et al., 1980); and for sustained low-intensity protocols, three

studies were reviewed (McKenzie et al., 1994; Morton, Fitch, & Davis , 1979; Reiff et al., 1989).

The interval warm-up protocol involves repeated sprints of 20-30 seconds at 100%+

maximum effort (VO2max or higher) as a warm-up before the workout challenge. The results were

compared to the same exercise challenge without the pre-challenge warm-up that acted as a control

for the study. Assessment of recovery time of lung function measures after exercise challenges

varied up to ten minutes to intervals of 15, 25, and 80 minutes.

Research by de Bisschop et al. (1999) examined the effects of warm-up protocols on

exercise-induced asthma in children with asthma to allow them to participate more fully in their

asthma-inducing activities. In the first study, peak flow measurements were assessed before,

during, and after (5 and 10 minutes) a seven-minute run (EX1) outdoors on the track in 16

asthmatic children (11 years on average). Then three pre-EX2 warm-up schedules were used with

varying intensity/speed (SRWU 1=100%, SRWU 2=120%, and SRWU 3=130%) on different

days.

This SRWU consists of a series of five short runs at a percentage of EX1 speed/intensity and 7.5%

of EX1 (distance achieved) with 1.5 minutes between runs and 5 minutes between two series of

runs and 10 minutes of recovery before EX2. In the second study, 30 young people with asthma

(an average of 12 years) did a seven-minute run alone (EX1) or the same run (EX2) after the

SRWU2 schedule. In all trials, the treatment was held for 12 hours before the test. The results

showed that in 24 of the 30 children, the decrease in PEF after EX2 was significantly less than the

decrease after EX1. The percentage decrease in PEF after EX2 was significantly correlated with

the same changes caused by the SRWU2 protocol. From the SRWU2 protocol, the children were

divided into three sub-groups: G1) increase in PEF, 10 or 30 subjects, G2), 15% fell on PEF, 14

out of 30 subjects, (G3). Fifteen percent fell in PEF 6 out of 30 subjects. Subgroup G3 did not

experience significant changes with the application of SRWU2 to EX2 recovery compared to EX1

recovery. The authors believe the change in PEF after the SRWU period is a good predictor of the

occurrence of bronchoconstriction after EX2. Thus, SRWU was able to reduce the decrease in PEF

for most children (24 or 30 subjects) in the study, thereby reducing subsequent post-exercise

bronchoconstriction. Subjects in the G1 and G2 sub-groups also increased their distance by 5%

from EX1 to EX2, indicating improved performance.

Mickleborough et al. (2007) investigated the efficacy of high-intensity interval warm-up

protocols and compared them to drug doses with salbutamol (a commonly used β2-agonist for the

prevention or relief of asthma symptoms) on the severity of EIB and whether the combination of

drugs and warm-up protocols provides greater protection against EIB with good interventions

alone. Eight moderately trained recreational athletes with documented EIBs were tested under

four experimental conditions: 1) control (CON); 2) interval warm-up (WU) consisting of 8x30

seconds of running at peak treadmill speed, with 45 seconds of recovery between each run; 3)

inhalation of 200μg of salbutamol (IH); and 4) combining WU and IH treatments. All four

interventions were followed by a 15-minute break and then subjects performed an exercise

challenge test (85-90% of the predicted maximum heart rate for eight minutes). Lung function is

measured before and after (recovery of 1, 5, 10, 15 minutes). Results revealed that in the CON

intervention, the average decrease in FEV₁ pre-to-post exercise in all eight subjects was -18.25%.

The mean decrease for the post-exercise WU intervention FEV₁ was significantly reduced to only

-9.1% (falling below the diagnostic threshold of a 10% decline in post-exercise FEV₁). IH and

WU+IH interventions resulted in significant bronchodilation with the maximum percentage of

mean change in FEV₁ post-exercise after IH increased +8.9% and WU+IH +15.2%. FEF 25-75%

also shows the same significance. The authors believe the data suggest that repeated high-intensity

heating may reduce EIB and that combining WU and IH interventions resulted in substantial

bronchodilation that added a protective effect against EIB development compared to interventions

alone.

McKensie et al. (1994) examined the protective effects of continuous low-intensity warm-

up and interval warm-up exercises on post-workout bronchoconstriction in athletes with exercise-

induced asthma. Twelve moderately trained subjects with asthma were tested under

three experimental conditions: 1) continuous heating (CW); 2) interval heating (IW); 3) control

(C). The CW intervention group performed a 15-minute treadmill run at a pace of 60% VO2max

followed by a two-minute rest and then an exercise challenge test (ET = 6 minutes at 90%

VO2max). The IW intervention group performed an 8x30-second run (a 1.5-minute rest between

each run) at an intensity of 100% VO2max, followed by a two-minute rest and then the same ET.

Group C only did ET. Measures of FVC, FEV₁ and mean maximum PEF (MMPEF) were assessed

(expressed as percentage change in baseline value) at rest before any exercise condition and every

2 minutes during the 25-minute passive recovery period. The results showed significant

differences in FEV₁, FVC, and MMPEF for CW (16.7, 10.7, and 30.2

%, respectively) above IW (29.7, 21.0, and 43.4%, respectively) or C (34.6, 30.0, and 50.0%,

respectively). The authors suggest a 15-minute CW workout at 60% VO2max can significantly

reduce post-workout bronchoconstriction in well-trained athletes with asthma. The results

showed that the CW protocol was significantly better than the IW protocol, but the IW was still

significantly better than the control. One can see a short rest period (2 minutes) between pre-

workout warm-ups as a limitation of this study that may lead to limited results for interval warm-

ups compared to continuous warm-ups.

Schnall et al. (1980) examined the idea of bronchodilation generated by short periods of

running in subjects where EIB occurred after a standard exercise test. Eight subjects (12-31 years)

with a history of prior EIB (free of asthma symptoms who had not received medication in the last

eight hours prior to testing) were tested on separate days with three trials. The trials were as

follows: 1) run twice (run A and run B) on a treadmill (10% incline and speed to produce a heart

rate of 180b/m) for six minutes each with a 49-minute break between each run (control); 2) do a

six-minute run (run C) followed by ten minutes

rest then seven short runs (120-130% of the six-minute run) of 30 seconds each with a 2.5-minute

rest period between each short run and then a 20-minute break followed by a second period of six-

minute runs (run D); and 3) do a seven-minute short run completed 20 minutes before the six-

minute run (run E). The data showed a significant change in the mean post-workout maximal

decline from baseline (rest) for PEF, FEV₁, and FEF25-75% measures comparing A run (control)

22.8, 23.0, and 37.3%, respectively, to E run (run after short run only) 10.4, 6.9, and 18.9%,

respectively. The values (FEV₁ and PEF) for running D revealed a significantly smaller decrease

in the change in the mean post-workout maximum in the running value A. The authors suggest

repeated short runs minimize the bronchoconstrictive effect on subsequent exercise stress and have

a bronchodilating effect on the previous EIB. They also suggest the data provide evidence to

support that people with asthma cope better with repetitive, short-duration activities and warm-up

periods may be beneficial in reducing the effects of longer exercise.

The four studies outlined above using interval protocols involved 52 subjects. The protocol

compares the percentage decrease in FEV₁ and/or PEF in the exercise trial with and without

(control) the previous interval warm-up. The spirometry measures after the exercise trial were

collected at different times (10, 15, 25, 80 minute increments). The interval warm-up protocol

consists of repeated sprints of 26-30 seconds at maximum intensity (≥100% VO2max). The mean

difference in the maximum percentage reduction in FEV₁ and PEF from the control exercise trial

compared to the warm-up exercise trial, ranged from about 4.9-16.1% and 11.6-30%, respectively.

The data support significant differences from control to interval heating protocols and the general

benefits of this type of protocol. The recovery time between warm-up and exercise tests varies

from 2 minutes to 20 minutes. Two studies reported performance measures (distance or VO2max)

during their studies; with de Bisschop et al. (1999) suggesting a 5% increase in spacin cover tracks

with interval warm-up and Mickleborough et al. (2007) reported no significant increase in

VO2max with interval warm-up alone.

The continuous high-intensity protocol involves continuous high-intensity heating with the

challenge of no-heating control exercises. The intensity of warm-up exercise was at the upper end

of VO2max (heart rate 180 or 98% of the max prediction) with the assessment of recovery

pulmonary function measured up to 80-90 minutes after the exercise challenge.

Reiff et al. (1989) examined the effects of prolonged warm-up periods of exercise on

subjects with AMDAL. Seventeen asthma subjects with known AMDAL were tested using two

different randomized exercise protocols: 1) a 6-minute treadmill trial at 6 kph and a 15% rate (S1A,

resulting in 98% of the predicted maximum heart rate): (continuous high intensity) followed by a

same exercise trial (S2A) with a 45-minute break between (day A); 2) 30-minute treadmill at 6

kph and 3% grade (W1B) with a 21-minute break (continuous low-intensity warm-up) followed

by the same exercise trial (S2B) used on day A (day B). The maximum percentage decrease in the

mean FEV₁ and PEF from the baseline is as follows: S1A= 46% and 51% respectively; S2A =

29% and 32% respectively; W1B = 17% and 21% respectively; S2B = 26% and 27% respectively.

Data supporting refractories are shown in S2A compared to S1A and that W1B produces

significantly less EIA than S1A with significant refractory to bronchoconstriction after S2B. The

authors concluded that the warm-up period of exercise can induce refractory to AMDAL without

automatically producing marked bronchoconstriction.

Schnall et al. (1980), as in the previous review, examined the continuous high-intensity

protocol vs. the interval heating protocol. Continuous high intensity made the subjects run twice

(run A and run B) on the treadmill (10% incline and speed to produce a heart rate of 180b/m) for

six minutes each with a 49-minute break between each run. Data showing interval heating protocol

superior to the continuous high-intensity protocol and had a more significant change in the mean

maximum post-workout fall from baseline (rest) than the use of running A (continuous high-

intensity warm-up) and then running B.

Continuous high-intensity protocols involving 25 subjects. The mean difference falling

from baseline for FEV₁ and PEF ranged from 6.9-17% and 10.4-21%, respectively. The data

support a significant difference from control to sustained high-intensity protocols and show some

of the benefits of this type of protocol. The recovery time between warm-up and exercise tests is

from 20 or 49 minutes. No studies reported performance measures.

The low-intensity warm-up protocol continuously uses a warm-up workout for three to 30

minutes with identical control challenges without prior warm-up. The intensity for this warm-up

protocol uses 60% HRmax, 60% VO2max, or just low-intensity heating (30-minute treadmill at 6

kph and 3% grade). Recovery lung function assessments were measured up to 25, 30, and 90

minutes after the exercise challenge.

Morton et al. (1979) set out to determine the effect of warming on the EIA. Eighteen

subjects (ten men and eight women) performed two five-minute sub-maximal treadmill trials to

achieve a heart rate of 85% of the maximum predicted for age with one preceded by

heating and those not preceded by heating (control). The warm-up protocol involves walking or

jogging on a treadmill for three minutes to produce 60% of the subject's predicted maximum heart

rate with less than a minute between warm-up completion and exercise test. The results showed

that the decrease in the mean maximum percentage of FEV₁ did not show a significant difference

from the two intervention trials (control and warming trials). The authors acknowledge that

although their study does not support the concept of warming to reduce the likelihood of an EIA,

Recommendations for longer, more intense warm-ups involving interval activity should be

considered with future studies.

McKensie et al. (1994) as previously reviewed compared continuous warm-up (CW) and

interval warm-up (IW) exercises on post-exercise bronchoconstriction in athletes with exercise-

induced asthma (EIA). Subjects tested under the CW protocol performed a 15-minute treadmill

run at a pace of 60% VO2max, followed by a two-minute rest, and then an exercise challenge test

(ET = 6 minutes at 90% VO2max). The results showed the CW protocol was significantly better

than the IW protocol but IW was still significantly better than the control.

Reiff et al. (1989) as previously reviewed, compared continuous high-intensity heating

and continuous low-intensity heating in subjects with EIA. The subjects were tested with a

continuous low-intensity warm-up protocol and performed a 30-minute treadmill at a speed of 6

kph and a 3% class warm-up with a 21-minute break followed by a trial exercise test. The data

showed continuous low-intensity heating protocols produced significantly less EIA than other

sustained high-intensity protocols.

Three studies using a continuous low-intensity protocol involved 47 subjects. The mean

difference falling from baseline for FEV₁ and PEF ranged from 16.7-29% and 30.2.-32%,

respectively. One study showed no significance in either measure (Morton et al., 1979). Most of

the data support a significant slight difference from control to sustained low-intensity protocols

and point to some limited benefits of this type of protocol. Recovery time between

Warm-ups and exercise tests start at zero, 2, or 45 minutes. The zero-minute break between

the warm-up protocol and the exercise test was also a study that did not show significance

with continuous low intensity. None of these studies reported performance measures. Table

1.1 summarizes the study.

1.8 Implications for Future Research

Many physiological mechanisms have been proposed as to why exercise can cause airway

refractory. The effects of exercise on the airway can result in dehydration of the airway surface,

leading to increased airway osmolarity. This increase in osmolarity creates inflammation, thereby

releasing the mediators prostaglandins, leukotrien, and histamine from mast cells that cause

bronchoconstriction (Anderson & Holzer, 2000). Anderson and Holzer (2000) noted that the

mechanism of EIB in asthma patients may have a different pathophysiological mechanism than

EIB in athletes. The cause of airway refractory is unclear, but it is suggested that catecholamine

depletion, increased circulation of prostaglandins, or degranulation of mast cell mediators are

possible reasons. Regardless of the reason, some researchers have tried to develop research that

creates refractories, thereby improving lung function in asthma sufferers and athletes. The idea of

a mechanism to consistently create refractory periods in individuals with EIB or non-EIB

individuals who perform strenuous intensity exercise that may be susceptible to EFL is particularly

interesting because it can improve fewer symptoms, decrease drug use, and improve exercise

performance ( When examining current and relevant research, one realizes that there is no single

heating protocol that is consistently used in multiple studies. Although similar protocols can be

grouped into general categories, such as intervals, continuous high intensity, and continuous low

intensity, there does not seem to be any agreement on the exact method to recommend. All

protocols reviewed used traditional training programs (aerobic-based or HIT-based) as the basis

of their warm-up programs. Five of the six studies that reviewed specific warming protocols found

significance in measures of lung function compared to controls. One study (Morton et al., 1979)

without significance in the measurement of lung function used a non-resting heating protocol

Table 1.1 Summary of heating protocols.

Learn

Year

Types of

protocols

Subject/C

ontrol

Definition

of % EIB

decrease

on FEV1

PFT

Heating protocol (WU)

Duration

: WU

and ET

(minutes)

Practice

Tests,

Time,

Type,

Intensity

% change in FEV1

and/or (PEF) breaks

Bishop

1999

Interval

36 (11-

year),

the

same

subject

≥15%

FEV1

PEF

5 short runs with EX1

speed/intensity percentages

(100, 120, or 130%) and

7.5% of EX1 (distance

achieved) with 1.5 minutes

between running and 5 minutes

between 2 running series

track@

maxim

effort

(26.8% more than

control means 37.9%

for 3 groups)

Mckenzie

1994

Interval &

12 (26.5

≥15%

FEV1

(continuous low intensity) CW

6m TM

CW=16.7%,

Continuousl

years),

FEV1

done for 15 minutes

@ 90%

IW=29.7%, and

Low

Intensity

Same

Subject

Treadmill Running at Speed

of 60% VO2max followed by

a two-minute break and then

VO2max

C=34.6%

(CW=30.2%,

IW=43.4%, and

sports challenge test (ET=6

C=50%)

minutes at 90% VO2max).

(Conscious) Preformed IW

8x30

Second round (1.5 minute break

between each run) at an

intensity of

100% VO2max, followed by

take a two-minute break and

then

The same ET.

Mickleborough

2007

Interval

8 (19.5

≥10%

FEV1,

(Hose) heating (WU)

8 minutes

9.1% above control

years),

FEV1

FVC,

consists of 8x30 seconds

CE@

from 18.25%

same

FEF

running at peak treadmill speed,

85-90%

Subject

25-

with 45-second recovery

MPHR

75%

between each run

(Table 1.1 continued)

Schnall

1980

Interval &

6 (12-31

PEF,

(control) & (continuous height-

49, 20

6m TM@

I=6.9% more

than

Continuousl

years),

FEV1,

intensitas) berlari dua kali (lari A

10%

included.

control

Hey-

same

FEF 25-

and run B) on the treadmill (10%

HR=180

23.0%

Intensity

Subject

75%

grade and speed to produce

(Me = 10.4%

heart rate 180b/m) to six-

more than

22.8%)

each minute with 49 minutes

IM=16%

pauses between each run

(14%)

(Mixed interval) IM do

six-minute run (C run)

followed by a ten-minute break

later

seven short runs (120-130% of

run six minutes) from 30 seconds

each with a rest period of 2.5

minutes between each short term

and then take a 20-minute break

followed by the second period

walk for six minutes (run D)

(Interval) carried out seven-

Short running minutes are

completed 20 minutes before

six minutes of running (E run).

Reiff

1989

Continuousl

17 (16-

≥15%

PEF,

(control) & (continuous height-

45, 21

6m TM@

CL=17%

Hey-

FEV1

intensity) treadmill 6 minutes

15%

included.

More Control

Intensity &

years),

Tested at 6 kph and 15% grade

& 6km*h

from 46%

Continuousl

same

(S1A, yields 98% of the max

97%

21% more

than

Low-

Subject

predicted heart rate) followed by

MPHR

51%)

Intensity

same exercise trial (S2A)

CH=29%

with a 45-minute break between

(32%)

(day A)

(continuous low intensity) a 30-

minute treadmill at 6 kph and

Value 3% (W1B) with 21-

Rest minutes then followed by

same practice test trial (S2B)

used on day A (day B).

(Table 1.1 continued)

Morton

1979

Continuousl

18 (11-

≥15%

FEV1

sub-maximum five minutes

5m TM @

Not

Low-

FEV1

Treadmill Running to Reach the

Heart

85%

meaning

Intensity

years),

85% rate of prediction

MPHR

same

maximum for ages with one

Subject

preceded by heating and one

no (control). Warming

Walking or jogging protocol

on the treadmill for three minutes

to produce 60% of the subject

Maximum predicted heart rate

with less than a minute between

Heating solutions to

sports tests.

interval between warm-up exercise and exercise test and may lead to a lack of observed airway

refractory. One study (Morton et al., 1979) with no significance in the measurement of lung

function used a warm-up protocol that had no rest interval between warm-up exercises and

exercise tests and may have led to a lack of observed airway refractory. When considering the

effects of pre-workout warm-up on performance measures, one study reported a 5% increase in

distance with a high-intensity warm-up protocol (de Bisschop et al., 1999).

There are still questions about what type of pre-workout warm-up is best suited for most

individuals experiencing EIB or EFL and what effects on performance can be expected. Also

interesting is what other ways/modes can be used to improve the action with pre-workout warm-

ups.

As previously reviewed, respiratory muscle fatigue can be a factor in the limitations and

development of EFL. Johnson et al. (1993) and Miller et al. (2006) suggested that although the

diaphragm has substantial aerobic capacity, it will exhibit significant fatigue during sustained

exhaustive exercise with an intensity greater than 80-85% VO2max. The force output required to

maintain VE during intense exercise requires significant muscle work (O2 demand) and a

significant proportion of cardiac output to meet the applied intensity. It has been suggested that

the use of RMT or VIH (non-traditional traditional training programs) can improve the

performance of resistance training in healthy and sick individuals (Hostettler et al., 2012).

Singh et al. (2011) concluded that four weeks of upper body endurance training (a traditional

endurance training program) resulted in significant changes in lung function in sedentary male

smokers. Thus, it seems promising that the concept of warming up for the respiratory muscles

directly will have some benefits. Throughout this review process, this author had no knowledge

of any studies that had used traditional or traditional non-traditional resistance

The training method is a pre-workout warm-up to directly warm the diaphragm and accessory

muscles.

Finally, a number of limitations need to be considered. First, can respiratory muscle fatigue

and subsequent EFL be avoided by warming up before exercise? Of the studies on respiratory

muscle fatigue and EFL reviewed, all involved measures of respiratory muscle fatigue and EFL,

and no study, to the best of this author's knowledge, examined the use of pre-workout warm-ups

to limit both. Second, is airway refractory a universal finding in individuals with and without

asthma? From pre-workout warm-up studies, all studied individuals with some degree of asthma.

It is important to determine any effect on airway refractory in non-asthmatic patients with pre-

workout warm-up. Thirdly, does the use of pre-workout warm-ups improve performance?

Reviewing pre-workout warm-up studies, only two studies (out of six reviewed) attempted the

measured performance outcomes. Only a study by de Bisschop et al. (1999) showed an

improvement in performance with pre-workout warm-ups. As such, further research should focus

on how exercise performance can be improved with the use of pre-workout warm-ups. Finally, are

there any other modalities that can be used to improve pre-workout warm-up results? From the

research reviewed, all pre-workout warm-up protocols included traditional types of training

activities. Can pre-workout warm-ups using non-traditional activities (RMT, VIH or upper body

resistance training) that directly focus on respiratory muscles improve lung function, but more

importantly exercise performance?

Considering these areas of limitation in the study reviewed, what are the practical

implications for athletes and people with asthma? As shown, pre-workout warm-up protocols

using traditional training methods showed improved lung function in various groups of subjects

with asthma. What if this increase could be extended to athletes who compete in

Some events with a little recovery break between those events? Can recovery duration be reduced

by pre-workout warm-ups using traditional and/or non-traditional activities? Can multi-event

athletes see an improvement in their next event performance?

In conclusion, in an effort to find more efficient ways to improve exercise performance,

this author believes an area that has shown benefits is the use of pre-workout warm-up protocols.

More specifically, the use of traditional protocols (aerobic and HIT types) combined with non-

traditional protocols (RMT, VIH, and resistance training) can be key to improving performance

for athletes and people with asthma. Future research along these lines should be considered.

CHAPTER 2. EXPERIMENT

2.1 Eksperimen 1

Introduction. Many authors have investigated the mechanics of the respiratory system and

its limitations during exercise; Likewise, respiratory muscle fatigue has been thoroughly examined

by measuring expiratory flow limitations (Babb, 2013; Bussotti dkk., 2009; Guenette dkk., 2007;

Swain, Rosenkranz, Beckman, & Harms, 2010), final expiratory lung volume (DeLorey, Wyrick,

• Babb, 2005; Guenette dkk., 2007), training flow volume loop (Nourry, Deruelle, dkk., 2005b),

respiratory work (Guenette dkk., 2007), ending the volume of inspirational lungs (Guenette dkk.,

2007), maximum inspiration pressure (Watsford, Murphy, & Pine, 2007), maximum expiratory

pressure (Watsford dkk., 2007), and bilateral transcutaneous supra-maximal phrenic nerve

stimulation (Johnson dkk., 1993). All of the studies mentioned above examined respiratory muscle

fatigue during exercise except for bilateral transcutaneous supra-maximal phrenicular nerve

stimulation studies. The concept of recovery of the respiratory system after exercise has not been

empirically studied, for example, the time it takes for the respiratory system to recover to a resting

level from maximum or near-maximum exercise performance and the readiness of the system for

other maximum or near-maximum exercise performance.

Given the lack of research in the field of post-exercise respiratory recovery, the following

experiment is to examine post-exercise respiratory system recovery [as measured by recovery flow

volume loop (RFVL) and return to resting level (FVL)]. The purpose of this study was to

determine the effect of various exercise intensities on the size of lung function (FVC, FEV1, FEF

25-75%, and PEF) during exercise recovery. The hypothesis of this study is that after exercising

for two minutes with a bicycle ergometer at three different intensity levels, (40, 65, and 90% of

the maximum predicted heart rate) the lungs

Function will differ significantly at 0, 5, 10, and 20 minutes post-workout recovery in young,

healthy individuals.

Method. Ten subjects on separate days at least 24 hours apart (five men and five women)

aged 18-32 (mean 22.6 years) performed two minutes of exercise at three different experimental

intensities (40, 65, and 90% of the predicted maximum heart rate) on an electronic brake cycle

ergometer (Ergometrics 800, Sensormedics). Subjects were instructed and self-reported that they

abstained from exercise, caffeine, and alcohol for 24 hours and did not eat whole foods three hours

before the test. A 1.5-mile run for a time was completed by the participants to estimate their

VO2max (George, Vehrs, Allsen, Fellingham, & Fisher, 1993; Larsen et al., 2002). Pulmonary

function through spirometry testing (FVC, FEV1, FEF 25-75%, and PEF) and cardiovascular data

[heart rate, blood pressure, and blood oxygen saturation (SpO2)] were measured before, during,

and after (0, 5, 10, and 20-minute intervals) of each trial. The study was conducted in a university-

based kinesiology laboratory and the population of study subjects was drawn from student

volunteers enrolled in the Human Performance Education course. In this study, volunteer subjects

were excluded based on health status from the Physical Activity Readiness Questionnaire (ParQ)

(individuals with asthma, smokers, pregnant women, and others who may be at risk of developing

exercise conditions were excluded). Voluntary subjects are informed of the potential risks of the

study and their written consent is given to participate before commencing the research. The study

was approved by the University's Institutional Review Board for the use of human subjects (see

Appendix).

Study Design. Subjects were randomly selected for trial conditions and completed an

informed consent form, ParQ, ran 1.5 miles, and demographic assessments were collected (height,

weight, body composition via bioelectrical impedance- Omron® HBF 306C, Omron,

Table 2.1.1: Demographics for Experiment 1.

Gender

5 males, 5 females

Age

22.6±9.4

Inches tall

67.15±7.2

Weight pounds

153.8±66.2

Body Mass Index

23.673±7.2

Body fat percentage

17.98±12.9

VO2max Estimate

43.341±14.8

Corp., Schaumburg, IL) (Lukaski, Bolonchuk, Hall, & Siders, 1986) before spirometry testing.

Upon arrival for their testing, subjects were given a disposable Microgard® Disposable Filter and

underwent resting spirometry followed by a randomized condition trial. Spirometry trials are

repeated as needed to achieve the ATS standard for spirometry testing. Data from each subject

(spirometry, BP, HR, SpO2) collected at each time interval (0, 5, 10, and 20 minutes).

The following testing days are followed by at least 24 hours between trials. The subject's heart

rate and SpO2 data were monitored by pulse oximetry (Nonin® 8600 pulse oximeter, Nonin

Medical Inc., Plymouth, MN). Once the resting spirometry data were collected, the subject took

a sitting position (the seat was adjusted with about 30º knee flexion) on the bike's ergometer and

began pedaling to maintain a speed greater than 60 rpm for two minutes. Pedaling resistance was

added to increase the subject's HR to the predicted maximum HR (40, 65, and 90% of the

maximum predicate heart rate) for at least the last 30 seconds of each bike trial. The resistance is

adjusted as needed to keep the subject's HR and pedaling rpm within the protocol range. After the

bike trial was completed, the subjects immediately sat down, put on the nose clip provided, and

began the recovery spirometry test. The recovery testing protocol completes after a 20-minute

data collection interval.

Measurement of Lung Function. The measures of spirometry are forced vital capacity

(FVC), forced expiratory volume in one second (FEV₁), forced expiratory flow of 25-75%

(FEF 25-75%), and peak expiratory flow (PEF). Sensormedics Vmax® 29c Pulmonary

Functional/Cardiopulmonary Exercise Testing Instruments are used to collect spirometry values

and the instruments (flow and volume sensors) are calibrated daily following the accuracy

standards of the American Thoracic Society (ATS) (M.R. Miller et al., 2005). The range of

laboratory atmospheres is as follows: 1) temperature 68-74°F, 2) relative humidity 60-70%, and

3) barometric pressure 758-766 mmHg. Infection control was administered by instructing subjects

to wash their hands when entering the laboratory and each subject was given a sealed bag for their

disposable Microgard® Disposable Filter. During all spirometry measurements, the subject is

asked to sit with his nose cut off, and instructions are given by an experienced technician on the

required tasks. All testing criteria follow the ATS evaluation standard (MR Miller et al., 2005).

Data Analysis. With demographic data collected prior to testing (age, sex), dependent

variables, such as included spirometry data (FVC, FEV₁, FEF 25-75%, and PEF), anthropometric

data (mass, stature, body fat and body mass index), and timed 1.5-mile runs (VO2 prediction)

were used during the study. The independent variables were 40%, 65%, and 90% MPHR, and

post-timed exercise (0, 5, 20, and 20 minutes). After the experiment, unidirectional repeated

ANOVA measurements were calculated across independent variables for each breathing

measurement and running time to determine if the breathing capacity had changed. The criterion

of statistical significance of correlation was set at p ≤ 0.05. All statistical tests were conducted on

SPSS version 21.0 (Chicago, IL, USA).

Result. Lung capacity did not change significantly based on the intensity of the exercise

performed. No difference in lung function was found at 0, 5, 10, or 20 minutes post-workout

recovery time. Normal cardiovascular response.

Discussion. The purpose of this study was to determine the effects of different exercise

intensities (40, 65, and 90% of the predicate heart rate) on lung size

Table 2.1.2: Comparison of ANOVAs between conditions and time

Variable

Condition F

Condition p

Time F

Time p

FVC

0.411

0.745

0.049

0.995

FEV1

0.393

0.409

FEF 25-75%

0.253

0.859

0.252

0.908

FEM

0.228

0.877

0.204

0.936

Note: Significance at p ≤ 0.05*

functions (FVC, FEV1, FEF 25-75%, and PEF) during exercise recovery; And it was hypothesized

that after two minutes of exercise with a bicycle ergometer at three different intensities, (40, 65,

and 90% of the predicate heart rate) lung function would differ significantly at 0, 5, 10, and 20

minutes of post-workout recovery in healthy young individuals. The data showed no statistical

difference between measures of lung function at the various intensities of exercise tested.

Some areas that may be weaknesses of the study include limited sensitivity of lung function

to the intensity of exercise used and the duration of the exercise trial not being broad enough to

cause changes in the respiratory system. Other sensitive methods can be used to determine greater

significance in distinguishing individual respiratory system changes during exercise. Nourry et al.

(2005) used a maximum volume-flow loop (MFVL) at rest and an exercise volume-flow loop

(EFVL) (plotted in MFVL) during a progressive exercise test until fatigue (duration eight to ten

minutes). The results showed higher FVC and maximum expiratory flow in trained subjects than

in untrained subjects thus suggesting that EFVL may be a more sensitive method of looking at

changes in lung function measures. Hill et al. (1991) studied a group of triathlons to see what

measures of lung function change during endurance triathlons (long duration, multi-events).

Pulmonary function is obtained after each event and 24 hours after the triathlon is over. After the

completion of the triathlon, a significant decrease from baseline was recorded in FVC (7.1%),

FEV₁ (8.4%), FEF 50% (18.6

%), FEF 25-75% (15.2%), but no changes in MVV or other FEF measures, ratios, and/or PEF were

indicated. These results suggest that the duration (>12 hours) of exercise is an important variable

that reflects a decrease in some measures of lung function. Although this study describes the length

of exercise that affects triathlon lung function, it still has to be determined at what time interval

the variable begins to decline; It seems that based on the current research protocol, it would be a

longer duration of more than two minutes.

There were limitations in this study, such as intensity control being difficult to monitor

due to the short duration of the activity protocol (two minutes) and intensity adjustment through

manual resistance resulting in a heart rate to respond more slowly than subject fatigue. Longer

training time durations may have helped control these limitations and allow for a more

comfortable increase in intensity. Second, the maximum recovery PFT (zero minutes after the

experiment) was difficult to obtain for the 90% intensity protocol because most subjects were

breathing maximally and it was difficult to complete the PFT when the subjects were panting. An

alternative to this limitation is to perform peak flow at maximum recovery and complete the first

PFT at one minute of recovery. Finally, the possibility that the number of subjects in this study

could undermine statistical reliability can never be discarded.

Conclusion. A two-minute exercise trial, at an intensity of 40, 65, and 90% of the

predicted maximum heart rate, was not taxing enough to produce a change in the size of lung

function in healthy young individuals. Although the data did not show significant changes in

the size of lung function with short duration of exercise with varying intensity, the beneficial

effects of such exercise cannot be ruled out.

2.2 Eksperimen 2

Introduction. Many exercise physiologists believe that the respiratory system has little or

no effect on limiting exercise performance in healthy individuals or athletes (A. McConnell,

2009), but the respiratory system faces some challenges during intensive exercise. For example,

partial alveolar pressure regulation of oxygen and carbon dioxide is achieved by a considerable

increase in alveolar minute ventilation (VE) often 20 times the resting value in humans. This large

increase in VE is achieved by the capacity of the respiratory muscles to not only produce alveolar

ventilation strength but also by limiting excessive physiological costs on the system during

exercise (Guenette & Sheel, 2007). An additional challenge that the respiratory system must

overcome is the ability of the bronchial (intra-thoracic) airways to maintain patency to allow for

the increased flow rate required during active expiration that is often seen in intense exercise.

During high-intensity exercise, the bronchial airways sometimes present significant limitations to

expiratory flow; thus leading to dynamic hyperinflation, increased respiratory muscle work, and

VE limitations (Forster et al., 2012).

The research on the value of pre-workout warm-up only uses traditional training protocols

and methods [high-intensity interval (HIT), continuous low-intensity (CLI), and continuous high-

intensity (CHI)] as the warm-up mode. Another possible way to reduce the demands on the

muscles of the respiratory system and alter lung function is the use of pre-workout breathing

warm-ups that involve non-traditional training methods. Non-traditional methods use respiratory

muscle training tools (inspirational and expiratory breathing methods) to warm up the respiratory

muscles. Based on my literature review, none of the studies used non-traditional warm-up

methods for warming up before sports performance, but some studies have

see the training effects of this type of training protocol (Griffiths & McConnell, 2007; Singh et

al., 2011; Weiner et al., 1992) on lung function.

Weiner et al. (1992) compared specific inspirational muscle training versus sham training

(placebo) on inspirational muscle strength and endurance in an adult bronchial asthma population.

The study looked at improvements in inspirational muscle strength and endurance as well as an

increase in FVC (force vital capacity) and FEV₁ (volume of forced expiration in one second) when

compared to a sham control group with six months of training. Griffiths and McConnell (2006)

investigated the effects of four weeks of inspirational muscle training and/or expiratory muscle

training and the subsequent effects of a combined six-week trial of inspirational and expiratory

muscle training on club-level rowers on rowing performance. The results of the study showed an

increase in inspirational and expiratory muscle strength as well as an increase in average strength

paddling performance. Singh et al. (2011) examined the effects of upper body endurance training

and conventional deep breathing exercises on lung function in male smokers. The results of the

study showed an improvement in lung function (FEV₁ and FEV₁/FVC). These studies suggest the

use of non-traditional training methods as an effective way to improve lung function, inspirational

and expiratory muscle strength, and exercise performance.

The physiological and performance benefits demonstrated by previously reviewed studies

of non-traditional training methods are hypothesized to also benefit individual lung function and

exercise performance when used as a pre-workout warm-up. The purpose of this study was to

determine which of the three conditions (inspired, expired, or combined) produced the best and

most intense warm-up as judged by the perceived exertion rating (RPE) for breathing, resulting in

a positive change (improvement) in PF action, and resulting in the most favorable recovery interval

for PF action. Of the three warm-ups (i.e. IM, EM, and CM), it

it is hypothesized that CM will stress the respiratory muscles to a greater degree (i.e. CM will

produce a higher RPE during the performance); and for all three warm-ups, the respiratory

muscles will recover within ten minutes (i.e. have the highest PF during recovery).

Method. Ten male subjects (Table 2.2.1) aged 18 to 30 years (mean 22.6 years) completed

each of the three warm-ups at 24-hour intervals. Subjects were instructed and self-reported that

they abstained from exercise, caffeine, and alcohol for 24 hours and did not eat whole foods three

hours before the test. The study was conducted in a university-based kinesiology laboratory and

the subject population was taken from student volunteers (comfort samples).

Subject inclusion is only male subjects while exemptions are based on the health status of

volunteers from the Physical Activity Readiness Questionnaire (ParQ) (individuals with asthma,

smokers, and others who may be at risk for sports treatment are excluded). In addition,

demographic assessment (height, weight, body composition through bioelectrical impedance-

Omron® HBF 306C, Omron, Corp., Schaumburg, IL) (Lukaski dkk., 1986) completed before

starting research for the use of standardized subjects. The study was approved by the University's

Institutional Review Board for the use of human subjects (see Appendix).

Table 2.2.1: Demographics for Experiment 2.

Gender

10 men

Age

22.6±7.4

Inches tall

68.2±5.2

Weight pounds

162.0±115.2

Body Mass Index

27.36±11.24

Body fat percentage

17.77±16.73

Study Design. Subjects practiced each randomly selected warm-up on separate days for

five minutes (actual breathing) while sitting with a nose clip. After each one-minute interval of a

five-minute warm-up, subjects were asked to provide a rated respiratory exertion (RPE point

scale 1-10, Appendix 1.D.) and perform peak flow (PF)

through a peak flow meter. A duration of fifteen seconds is allowed to complete the RPE and PF

measurements and then the warm-up is resumed. Each random warm-up was performed for a

total duration of six minutes after fifteen seconds were added to assess RPE and PF at each one-

minute interval. PF data is recorded for up to ten minutes (intervals of 1, 2, 3, 4, 5, 6, 8, and 10

minutes) after completion of warm-up and labeled as recovery.

Respiratory warming. The three warm-ups/respiratory treatments performed for this

study were: inspirational (IM), expiratory (EM), and combined inspirator and expiratory (CM).

For IM, the subject inhales deeply and strongly into the inspiration capacity (IC) at the fast flow

on an incentive spirometer (IS) device that measures the volume of inspiration while providing

visual feedback on the high, medium, and low flow generated. After inhaling, the subject was

asked to hold the breath for five seconds, and then exhale slowly with moderate force to the

residual volume (RV). In EM, subjects are asked to inhale slowly into the IC, hold their breath

for five seconds and then exhale forcefully with rapid flow into the RV via a Resistex®

Mercury® Resistance Exercisers (RM) device with variable expiratory resistive load settings

[one to four (minimum to maximum)]. The expiratory resistive load is four for each subject. For

CM, the subject is required to inhale deeply and strongly into the fast-flowing IC on the IS device,

hold the breath for five seconds, and then exhale forcefully in rapid flow through the RM device

to the RV. All warm-ups are practiced for five minutes (actual breathing) in a sitting position and

wearing a nose clip.

Data Analysis. RPE and PF were the dependent variables in this study while the

independent variables were heating/treatment (IM, EM, and CM). After the experiment, a t-test

paired sample was calculated to compare data from pre-heating to

during heating (Table 2.2.2). The criterion of statistical significance of correlation was set at p ≤

0.05. All statistical tests were conducted on SPSS version 21.0 (Chicago, IL, USA).

Result. As mentioned in Figure 2.2.1, CM results in an increase in PF after five minutes of

warm-up. In addition, CM produces a fairly consistent pattern of increasing PF values. The IC

showed a consistent decline during the warming period, but the EC had an erratic response up and

down. Data from the RPE during warm-up are presented in Figure 2.2.2. The displayed RPE

increases progressively during each warm-up with CM resulting in the highest RPE value after

five minutes. The data in Figure 2.2.3 shows the highest PF value was achieved at four minutes of

recovery for all heating conditions. PF decreased after four minutes for all three warm-ups with

CM remaining highest at eight and ten minutes of recovery. Overall, however, the pattern between

heating procedures is essentially the same for each procedure.

The paired sample t-test showed there was a significant difference in CM warming at RPE4

(M = 3.800, SD = 1.398) and RPE5 (M = 4.500, SD 1.509); t(9) = -3.280, p = 0.010. Nothing else

variables were found to be statistically significant (Table 2.2.2).

Discussion. Although this is the first known study to investigate the effects of respiratory

warming on RPE and PF, the aim of this study was to determine which of the three warm-ups (IM,

EM, or CM) produced the best and most intense warm-up as judged by the perceived level of

exertion (RPE) for breathing, resulting in a positive (increasing) change in PF size. In addition, the

most favorable recovery interval is to determine how PF measures are investigated. It is

hypothesized that between the three warm-ups, the CM will stress the respiratory muscles to a

greater degree (i.e. a higher RPE during the performance) and regardless of the warm-up, the

respiratory muscles will recover within ten minutes (i.e. the highest PF observed during recovery).

Figure 2.2.1: Average PF over the time interval for warm-up.

Figure 2.2.2: Average RPE over the warm-up time interval.

607

603

Warm-up time interval in minutes

604

Inspiring

Combined

Expiration

595

591

602

604

611

613

L/dtk. 610

605

600

595

590

585

615

619

618

624

634

640

635

630

625

620

615

Average PF during Warming Over

Time

0 1 2 3 4 5 6

Warm-up time interval in minutes

Inspiring

Combined

Expiration

1.5

0.5

2.4

scale

3.4

32.9

2.6

1-10 2.5

4.5

4.2

3.9

3.6

3.8

3,8

2.9

3.5

RPE

4.5

Average RPE during Warming Over

Time

Figure 2.2.3: Average recovery RPE time interval.

Table 2.2.2: T-test data for Peak Flow and RPE during warm-up: IM=Inspiratori,

EM=Expiratory and CM= Inspiratorial/Expiratory

Condition

Mean

Std. Deviation

Sig. (2-echo)

Peak Flow (PF)

Pra-PF

607.5000

73.68288

0.112

0.913

PF5

604.5000

117.05768

Pra-PF

616.5000

75.57373

1.342

0.212

PF5

595.5000

66.35134

CENTIMETR

Pra-PF

591.0000

81.16513

-1.637

0.136

PF5

624.5000

102.91447

Peak Flow (PF)

PF1

613.5000

79.16404

0.424

0.681

PF5

604.5000

117.05768

PF1

618.0000

73.15129

1.317

0.220

PF5

595.5000

66.35134

CENTIMETR

PF1

611.0000

89.00062

-0.566

0.585

PF5

624.5000

102.91447

Peringkat Perceived Exertion Breathing (RPE)

RPE4

3.6000

1.34990

-1.964

0.081

RPE5

3.9000

1.59513

RPE4

4.0000

1.12472

-1.500

0.168

RPE5

4.2000

1.22927

CENTIMETR

RPE4

3.8000

1.39841

-3.280

0.010*

RPE5

4.5000

1.50923

Note: Significance at p ≤ 0.05*

Pre-PF = resting PF, PF1 = PF at 1 minute of treatment, PF5 = PF at 5 minutes of treatment,

620

609

600

590

580

570

560

607

605

583

572

600

582

Inspiring

Combined

Expiration

Time interval in minutes

617

610

593

618

L/dtk. 610

630

631

625

620

639

637

650

641

631

660

650

640

630

PF Average Recovery Over

Time

The data in Figure 2.2.1 shows PF during three different warm-ups at the end of five

minutes of treatment. CM resulted in an increase in PF after five minutes while producing a fairly

consistent pattern to increase PF values until the end of treatment. The CM protocol requires

forced inhalation and exhalation in the breathing cycle, thus emphasizing the use of inspirational

and expiratory muscles. The IC and EC protocols require only forced inhalation or exhalation,

respectively, therefore emphasizing one side of the respiratory cycle. Because CM uses the use of

bilateral respiratory muscles, it is believed that the work creates a greater airway flow than the

other one-sided breathing movements (IC and EC). Movements like this increase the range of

motion of the respiratory muscles which allows for greater preparation of the respiratory system

for the next forced inhalation and exhalation as seen in the PF maneuver.

The information provided in Figure 2.2.2 shows the RPE increasing progressively with

each warm-up with CM resulting in the highest RPE value after five minutes. Paired sample t-

tests support these results showing a statistically significant improvement in CM at RPE4 vs.

RPE5. Since there is an effect in forced inspiration of CM and forced expiration, an increase in

intensity is created throughout the breathing cycle. Although all warm-ups use a complete

breathing cycle, the forced nature of the CM provides increased intensity. However, it is worth

noting the difference in real numbers between small RPE heating (3.9 IM, 4.2 EM, 4.5 CM).

The data from Figure 2.2.3 shows all heating progressively increasing the PF value at one

minute of recovery to the peak PF value at four minutes of recovery with the PF value decreasing

thereafter. At the eight and ten-minute recovery periods, the CM PF remained the highest of the

three warm-ups. These findings continue to demonstrate the power of two sides

The involvement of the respiratory muscles in CM warm-up allows the system to stay in top shape

for longer.

Some limitations of this study include calculations and comparisons made with each

heating (i.e. CM, Pre-PF to CM PF5) and not across the entire heating (i.e. IM to CM). Second,

the use of PF maneuvers can display various values based on the subject's effort as shown in figure

2.2.1. Third, EC produces inconsistent patterns related to poor stability in subject endeavors.

Coaching more consistent PF maneuvers and repeated efforts for the best grades will help alleviate

these inconsistencies. Lastly, small sample sizes weaken statistical reliability.

Conclusion. For each of the three warm-ups, five minutes seems to be enough duration to

help with breathing without a particularly challenging body system (RPE of 4). During CM, PF

increases from the beginning of treatment and has a consistent pattern that makes sense after five

minutes. On the other hand, IM and EM decreased at the end of five minutes. In recovery, all

conditions reached their highest value at four minutes and continued to decline thereafter. Despite

this decline, CM remained highest at ten minutes of recovery. Based on these findings, CM

appears to be the optimal respiratory warm-up for subsequent experiments.

2.3 Eksperimen 3

Introduction. Many exercise physiologists believe that the respiratory system has little or

no effect on limiting exercise performance in healthy individuals or athletes (A. McConnell,

2009), but the respiratory system faces some challenges during intensive exercise. One example

is the partial alveolar pressure regulation of oxygen and carbon dioxide achieved with a

considerable increase in alveolar minute ventilation (VE) often 20 times the resting value in the

human. This large increase in VE is achieved by the capacity of the respiratory muscles to not

only produce alveolar ventilation strength but also by limiting excessive physiological costs on

the system during exercise (Guenette & Sheel, 2007). Another example that challenges the

respiratory system to address is the ability of the bronchial airways (intra-thoracic) to maintain

patency to allow for the increased flow rate required during active expiry often seen in intense

exercise. During high-intensity exercise, the bronchial airways, at times, present significant

limitations to expiratory flow; therefore, it causes dynamic hyperinflation, increased work of

respiratory muscles, and limitation of VE (Forster et al., 2012).

An often overlooked ingredient for possible limitations of the respiratory system is how

the mechanical workings of breathing have sensory and metabolic impacts. Perceived breathing

work contributes to how hard the exercise feels (sensory) and the demands of the mechanical work

of breathing places on the circulatory system for blood and oxygen to maintain muscle contraction

(metabolic) (A. McConnell, 2009). It has been suggested that the metabolic and circulatory costs

of high respiratory mechanical work during maximum VE levels can amount to 8-10% of VO2max

(maximum oxygen consumption) and cardiac output in untrained individuals and up to 14-16%

VO2max and cardiac output in highly trained individuals (Aaron et al., 1992; Harms, McClaran,

et al., 1998). It is further noted that, with studies on the distribution of blood flow, when the

respiratory muscles are loaded, vasoconstriction reflexes are produced which results in a decrease

in blood flow to the exercising limbs. Conversely, when the respiratory muscles are dismantled, a

state of increased blood flow (dilation) exists in the muscles of the legs that are exercising (Harms,

Wetter, et al., 1998). This change in limb blood flow suggests a competitive relationship between

the motor muscles and the respiratory muscles for limited cardiac output (Guenette & Sheel, 2007).

These findings may represent

the respiratory system's challenge to maintain airway patency in the face of maximum or near-

maximum workload, creating high VE demands, competition for available cardiac output with

limb muscles, and variation in respiratory muscle fatigue.

Research on the value of pre-workout warm-up uses only traditional training protocols and

methods [high-intensity interval (HIT), continuous low-intensity (CLI), and continuous high-

intensity (CHI)] as the warm-up mode (McKenzie et al., 1994; Reiff et al., 1989; Schnall &

Landau, 1980). Reiff et al. (1989) examined the effects of prolonged periods of exercise warm-up

in subjects with exercise-induced asthma (EIA) and found that CLI and CHI warm-up showed

benefits (protection from EIA) for their subjects. McKensie et al. (1994) examined the protective

effects of CLI warm-up and interval warm-up exercise (IW) on post-workout bronchoconstriction

in athletes with EIA and their findings showed the CLI protocol was significantly better than the

IW protocol, but the IW was still significantly better than the control group. Schnall et al. (1980)

examined the idea of bronchodilation produced by short periods of running (HIT) in subjects where

EIB occurred after a standard exercise test.

Their findings suggest that repeated and short-term use minimizes EIB and has a

bronchodilating effect on previous EIB. Their research also suggests that the data provide

evidence to support people with asthma coping better with repetitive, short-duration (HIT)

activity and warm-up periods may be beneficial in reducing the effects of longer exercise. The

study suggests the use of traditional training protocols as a pre-workout warm-up that provides

subjects with positive changes in their lung function and reduces EIB.

Another possible way to reduce the demands on the muscles of the respiratory system and

alter lung function is the use of pre-workout breathing warm-ups that involve non-traditional

training methods. Non-traditional methods will use breathing muscle exercises

device (inspirational and expiratory muscle method) to warm up the breathing muscles. Based on

this author's literature review, no studies have been examined on non-traditional warm-up

methods for pre-workout warm-up, but some studies have looked at the training effects of this

type of training protocol (Griffiths & McConnell, 2007; Singh et al., 2011; Weiner et al., 1992)

on lung function. Weiner et al. (1992) compared specific inspirational muscle training versus

sham training on inspirational muscle strength and endurance in an adult bronchial asthma

population. Observations of increased strength and endurance of inspirational muscles were found

as well as an increase in FVC (force vital capacity) and FEV₁ (volume of forced expiration in one

second) when compared to a sham control group with six months of training. Griffiths and

McConnell (2006) investigated the effects of four-week inspirational muscle and/or expiratory

muscle training and the subsequent effects of a combined six-week trial of inspirational and/or

expiratory muscle training on club-level rowers on rowing performance. The results showed an

increase in inspirational and expiratory muscle strength along with an increase in average strength

paddling performance. Singh et al. (2011) examined the effects of upper body endurance training

and conventional deep breathing exercises on lung function in male smokers. The results showed

an improvement in lung function (FEV₁ and FEV₁/FVC). The study shows the use of non-

traditional training methods is an effective way to improve lung function tests, inspirational and

expiratory muscle strength, and exercise performance.

Since traditional training methods used as pre-workout warm-ups show positive changes

in lung function and performance, one can conclude that non-traditional training methods used as

pre-workout warm-ups can show similar benefits. The concept of a non-traditional method used

as a pre-workout warm-up to improve the respiratory muscles

Lung function and exercise performance are new ideas and worth investigating. Thus, if warming

up the breathing can improve the mechanical advantage of the respiratory muscles before exercise,

the subject can reduce the need for oxygen and cardiac output during the initial stage of exercise.

If oxygen consumption and cardiac output requirements from the respiratory muscles may be

reduced during the early stages of exercise performance than might be expected to appreciate the

recovery benefits as well. Based on the results of the second trial in this study, the combination of

inspirational and expiratory respiratory warm-up conditions/(IEC from now on) showed better

results (PF was most intense and increased) compared to one of the other conditions studied by

inspiration (IC) and expiratory (EC) alone. Thus, the experiment was an expanded examination of

the effects of IEC (heating) on performance, respiratory rating of perceived exertion, and lung

function. The purpose of this study was to evaluate the impact of pre-exercise respiratory warm-

up using non-traditional methods (a combination of inspirational and expiratory muscle training

modalities) (IEC) on measures of lung function (FVC, FEV₁, FEF 25-75%, PF), performance time

(300-yard shuttle and 1.5-mile run) and perceived activity respiratory recovery rating (RPE). Thus,

it is hypothesized that the use of pre-exercise respiratory warm-up using non-traditional methods

(a combination of inspirational and expiratory muscle training modalities) will increase the size

of lung function (FVC, FEV₁, FEF 25-50%, PEF)

and improved performance (reduced completion time) achieved in the space shuttle for 300 yards

and a 1.5-mile run compared to controlled conditions (CC) (no warm-up). The secondary

hypothesis is that the subject's fitness status will not be associated with a decrease in performance

time and the subject will rate the perceived level of respiratory exertion (RPE point scale 1-10,

Appendix 1.D.) as lower during recovery from each run after warm-up breathing (IEC).

Method. All twenty male subjects aged 20 to 34 years (mean 24.3 years) completed four

study sessions (Table 2.3.1). In addition, two subjects started the session but were unable to

complete the entire study due to scheduling conflicts; Therefore, their data was not included in

this experiment. The research was conducted in a university-based kinesiology laboratory and

gymnasium with the subject population taken from student volunteers (comfort samples). Subject

inclusion is only male subjects while exemptions are based on the health status of volunteers from

the Physical Activity Readiness Questionnaire (ParQ) (individuals with asthma, smokers, and

others who may be at risk for sports treatment are excluded). Subjects are informed of the potential

risks and give written consent to participate before commencing the study. The study was

approved by the University's Institutional Review Board for the use of human subjects (see

Appendix).

Upon completion of informed approval, ParQ, and basic data (height, weight, percent body

obesity via bioelectrical impedance- Omron® HBF 306C, Omron, Corp., Schaumburg, IL)

(Lukaski dkk., 1986) to standardize the subjects, all subjects performed an initial series of resting

PFTs followed by randomly assigned (CC) resting (no heating) control conditions (CC) for five

minutes or respiratory warm-up for five minutes using the IEC warming protocol. Subjects were

instructed to perform the following warm-up of breathing: 1) Inhale deeply and vigorously to the

capacity of inspiration (IC) with a rapid flow on an incentive spirometer (an IS- device measures

the volume of inspiration while providing visual feedback on the high, medium, and low flow

generated); 2) Hold your breath (breath) for five seconds; 3) Exhale vigorously with a rapid flow

to residual volume (RV) through the Resistex® Mercury® Resistance Exercisers (RM) device

with variable expiratory resistive load settings (set at the highest 4 resistances) to the RV. After

five minutes of CC (no warm-up) or IEC (warm-up) is complete, the subject rests for five minutes

and then

did a 300-yard (50-yard each way) shuttle run (Cumming & Keynes, 1967) or a 1.5-mile run (a

running line for a consistent distance) (Larsen et al., 2002) for time in the gym [all subjects

completed CC (no warm-up) and IEC (warm-up) on different days for both runs]. Subjects are

allowed to do limited independent stretching before running. After completing the run, the subject

returned to the kinesiology laboratory for recovery testing starting with PF and RPE for every

minute for 15 minutes. At intervals of 5, 10, and 15 minutes, PFT data was collected.

During each assessment interval, the subject sat down and the nose was cut. The test sequence

takes four days (two days for CC and two days for IEC) to complete. All subjects completed two

300-yard shuttle runs (one with warm-up, one without) and two 1.5-mile runs (one with warm-up,

one without). Subjects were instructed and self-reported that they abstained from exercise,

caffeine, and alcohol for 24 hours and did not eat whole foods three hours before the test. Testing

sessions are spaced 24 hours apart. Fitness status was determined by predicting subjects' VO2max

from their best 1.5-mile run time (George et al., 1993; Larsen et al., 2002).

Table 2.3.1: Demographics for Experiments 3.

Gender

20 men

Age

24.2±9.8

Inches tall

68.1±5.1

Weight pounds

163.5±76.5

Body Mass Index

24.6±16.2

Body fat percentage

11.7±10.9

VO2max Estimate

44.9±14.9

Measurement of Lung Function. The spirometry measures used were forced vital

capacity (FVC), forced expiratory volume in one second (FEV₁), forced expiratory flow of 25-

75% (FEF 25-75%) and peak expiratory flow (PEF). All lung measurements were performed

with the Sensormedics Vmax® 29c Pulmonary Function Testing/Cardiopulmonary Exercise

Instrument. Instruments (flow and volume sensors) are calibrated daily after American Thoracic

C M

• Random Run (300-yard shuttle or 1.5-mile run).

• Each subject completed one 300-yard shuttle run with no warm-up (CC)

and one warm-up (IEC).

• Each subject completed one no-heat run (CC) and one warm-up (IEC) 1.5-mile

run.

RPE/PF

PFT

Figure 2.3.1: Flowchart of subjects, interventions, and analysis.

• Test t-samples paired from dependent variables (road performance time, RPE,

FVC, FEV₁, FEF 25-75%, and PEF to independent variables [condition: no

heating (CC) v. heating (IEC)].

• PFT recovery at 5, 10, and 15 minutes.

• RPE is immediately to be executed upon completion.

• RPE and PF 1 minute (continued every minute up to 15 minutes).

• Random sitting conditions for 5 minutes (CC=no heating, IEC=heating).

• Rest for 5 minutes both conditions.

• Rest assessments: Initial PFT (FVC, FEV₁, FEF 25-75%, PEF), RPE, and PF.

• Informed consent.

• Early Demographics (height, weight, BMI, body fatness, age, gender).

• Subjects were screened (ParQ) and enrolled in the study (n=22).

• 2 subjects could not be resolved (schedule conflict).

• Total study subjects were male (n=20).

Community accuracy standards (ATS) (MR Miller et al., 2005). The range of laboratory

atmospheres is as follows: 1) temperature 68-74°F, 2) relative humidity 60-70%, and 3) barometric

pressure 758-766 mmHg. Infection control is administered by instructing subjects to wash their

hands when entering the laboratory and each subject is given a sealed bag for an assigned

Microgard® Disposable Filter that is only used by them for each spirometry test. During all

measurements, subjects sit down, their noses are cut, and they are instructed on proper testing

techniques by experienced technicians. All testing criteria follow the ATS evaluation standard

(MR Miller et al., 2005).

Data Analysis. The dependent variables include performance time, RPE, FVC, FEV₁, FEF

25-75% and PEF and the independent variables are no-heating (CC) and heating (IEC) conditions.

After the experiment, paired sample t-tests were calculated to compare no heating (CC) and

heating (IEC) data. In addition, VO2max is plotted against the percentage increase for running

time. The criterion of statistical significance of correlation was set at p ≤ 0.05. All statistical tests

were conducted on SPSS version 21.0 (Chicago, IL, USA).

Result. There is a significant difference in the 300-yard shuttle run as shown in Figure

2.3.2 for direct post-run RPE between no warm-up (CC) (M= 8.65, SD=0.587) and warm-up

(IEC)(M=9.1, SD=0.718); t(19)=-2.269, p=0.035, two-minute recovery of RPE without

warm-up (CC) (M=6.15, SD=1.268) and warm-up (IEC) (M= 6.8, SD=1.508); t(19)=-3.115,

p=0.006, and the seven-minute RPE without heating (CC) (M= 3.5, SD=1.235) and heating (IEC)

(M=4.05, SD=1.356); t(19)=-2.463, p=0.024. No other paired samples showed significance for

RPE recovery in the 300-yard shuttle run as well as in Figure 2.3.3 for the 1.5-mile run. The data

in Figure 2.3.4 shows no relationship between VO2max and the percentage increase in

performance time for a 300-yard shuttle and a 1.5-mile run.

Figure 2.3.2: Average recovery RPE for a 300-yard shuttle run compares no warm-up (blue bar)

and warm-up (red bar) to standard deviation and significance at p ≤ 0.05*.

Figure 2.3.3: Average recovery RPE for a 1.5-mile run comparing no warm-up (blue bar) and

warm-up (red bar) to standard deviation and significance at p ≤ 0.05*.

Run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Recovery Time in minutes

RPE

1-10

scale

Warming

No heating

300 yards Shuttle Run RPE vs. Recovery Average

Time

Average Recovery RPE 1.5 Mile vs. Time

No heating Warming

RPE

1-10 6

scale 4

0 Lari 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Recovery Time in minutes

Figure 2.3.4: VO2max plotted with a percentage increase for a 300-yard shuttle performance

time and a 1.5-mile run.

The comparison in Figure 2.3.5 shows no significant difference for no heating (CC) and

heating (IEC) for the subject's performance time in the space shuttle of 300 yards (seconds); In

contrast, Figure 2.3.6 for a 1.5 mile (minute) run shows the difference in significance from no

warm-up (CC) (M= 13,108, SD=2,194) and warm-up (IEC) (M=12,683, SD=1,855);

t(19)=2.160, p=0.044

for the subject's performance time.

Figure 2.3.5: Average performance time for a 300-yard shuttle run compares no warm-up

Relationship % Increase v. VO2max for 300 yard shuttle

run and 1.5 mile run

VO2maks

ml/kg/mnt

VO2max

Estimate

-15 -10 -5 0 5 10

% Increase

52 seconds

Time

Average Performance Time for a 300-Yard Shuttle

Run

No heating

Warming

Shuttle Run 300 yd

Figure 2.3.6: Average performance time for a 1.5-mile run comparing no-warm-up (blue bar)

and warm-up (red bar) to standard deviation and significance at p ≤ 0.05*.

Recovery lung function data for no warm-up (CC) compared to warm-up (IEC) for a

300-yard shuttle and a 1.5-mile run, are presented in Figures 2.3.7 and 2.3.8, with respect. There

was a difference in significance for FVC for no heating (CC) (M= 4.732, SD=0.626) and heating

(IEC) (M=4.607, SD=0.631); t(19)=3.197, p=0.005 and FEV₁ for no heating (CC) (M= 3.960,

SD=0.587) and heating (IEC) (M=3.860, SD=0.607); t(19)=3.050, p=0.007 for

The 300-yard shuttle runs at ten-minute intervals (Figure 2.3.7) and at FEV₁ for a 1.5-mile

(minute) run for no warm-up (CC) (M= 3.852, SD=0.556) and warm-up (IEC) (M=3,722,

SD=0.424); t(19)=2,160, p=0.017 at a ten-minute recovery interval (Figure 2.3.8). No other

paired samples of lung function values showed significance.

Discussion. This is the first known study to investigate the effects of respiratory warming

on respiratory recovery RPE, running performance time, and recovery lung function; therefore,

the purpose of this study was to evaluate the effects of respiratory warming using combined

inspiration/expiratory respiratory warming (IEC) on perceived exertion respiratory recovery

(RPE) ratings, performance time (300-yard shuttle and 1.5-mile run), and lung function

Average Performance Time for a 1.5 Mile

Run

Minut

e time

No heating

Warming

1.5 Mile Run

Figure 2.3.7: Mean recovery PFT values for a 300-yard shuttle run comparing no warm-up at 5

minutes (light blue bar), at 10 minutes (gray bar), at 15 minutes (dark blue bar), and warm-up at

5 minutes (orange bar), at 10 minutes (yellow bar), at 15 minutes (green bar), with a standard

deviation and significance at p ≤ 0.05*.

Figure 2.3.8: Average recovery PFT values for a 1.5-mile run comparing no warm-up at 5

minutes (light blue bar), at 10 minutes (gray bar), at 15 minutes (dark blue bar), and warm-up

at 5 minutes (orange bar), at 10 minutes (yellow bar), at 15 minutes (green bar), with standard

deviation and significance at p ≤ 0.05*.

Average Recovery PFT Value for 300 Yard Shuttle Run

Volume 6

No Heating 5m

Heating 5m

No heating 10m

10m No heating

15m

15m heating

FVC (L)

FEV₁ (L) FEF 25-75% PEF

(L/dtk)

Average Recovery PFT Value for a 1.5 Mile

Run

Volume 6

No Heating 5m

5m heating

No heating 10m

10m No heating

15m

15m heating

FVC (L)

FEV₁ (L) FEF 25-75% PEF

(L/dtk)

(L/s)

sizes (FVC, FEV₁, FEF 25-75%, and PEF). The secondary objective of the study was to determine

whether the improvement in the performance of the subjects was affected by their fitness status

(VO2max). Data presented on the RPE of running recovery between no warm-up (CC) and warm-

up (IEC) showed there was a significant difference for the 300-yard shuttle run at the immediate

post-run RPE, 2-minute recovery RPE interval, and 7-minute and no difference in significance

was shown for the 1.5-mile running recovery RPE for both conditions. Performance time in a 1.5-

mile run decreased by an average of 25 seconds (a 3.2% increase) with warm-up (IEC) compared

to no warm-up (CC). The suggested significant differences for FVC and FEV₁ at ten-minute

intervals for the 300-yard shuttle run and FEV₁ at ten-minute intervals for the 1.5-mile run are

inconsistent with the stated hypothesis; because it is believed that heating (IEC) will improve

lung function. The remaining pulmonary function values have no statistical significance.

The study showed no association between VO2max and a percentage increase in the performance

time of both runs.

Data on the RPE of the recovery of the run showed there were several time intervals

(immediate post-run, 2 and 7 minutes) with significant differences between no warm-up (CC) and

warm-up (IEC) for the 300-yard shuttle run but not the 1.5-mile run. This difference suggests that

warming (IEC) actually increases the RPE in recovery. This result was possible due to the

anaerobic nature of the run (300-yard inter-space) which overloaded the respiratory system to the

maximum for a short duration and was exacerbated by the perception of warmth (IEC) just five

minutes earlier.

In addition, individuals without a history of breathing difficulties, as seen in this population of

healthy young men, adjusted to the demands of metabolism so that they did not need the benefits

provided by the respiratory warm-up used in this study (Forster & Pan, 1988). As previously

reviewed, in healthy individuals, the dynamic capacity of inspiration and excitation The muscles

to produce forced may never limit VE's response to exercise (Guenette & Sheel, 2007), which is

a plausible explanation for the lack of improvement seen in both runs (300-yard and 1.5-mile

shuttles) of this population.

The study showed a significant 3.2% improvement in performance time in a 1.5-mile run

after warm-up breathing (IEC). As shown by de Bisschop et al. (1999) a similar improvement was

seen after the traditional warming protocol of their study in children with asthma. Children

increasing their distance by 5% showed improved performance.

Anecdotal observations in the study found subjects felt less breathing at the start of a 1.5-mile

run after warm-up (IEC); however, their recovery RPE did not change when compared to no

warm-up (CC). How this lower perception at the beginning of training contributes to improved

performance; And if so, in what way? Studies on fatigue time (performance) using respiratory

muscle loading and unloading showed that loading through resistive devices resulted in a

decrease in time to fatigue and unloading with PAV increased time to fatigue by an average of

±14-15% (Harms et al., 2000). These results suggest that the improved performance (time to

fatigue) effect can be explained by reduced perception of secondary dyspnea to reduced

respiratory muscle work (Miller et al., 2006).

Logically, warming up the respiratory system directly before sports performance should reduce

the perception of dyspnea, reduce the work of the respiratory muscles, and result in improved

performance. One possible mechanism of this process can be described as system priming as seen

in traditional heating modalities reviewed earlier by many authors.

It is theorized that respiratory heating (IEC) will improve lung function compared to no

heating (CC). These findings showed statistically significant reductions in FVC (2.7%) and FEV₁

(2.5%) at ten-minute intervals for the 300-yard and FEV₁ shuttle runs

(3.3%) at ten-minute intervals for 1.5 miles for warm-up. These results are similar to the study

produced by Coast et al. (1999) which showed the effect of the maximum exercise trial

(progressive maximum cycle ergometer test) on healthy subjects. A significant decrease in FVC

(7%) was observed immediately after the trial. The authors suggest the data suggest lung function

and respiratory muscle strength may be altered after exercise; However, it is important to note, the

data of this study should be viewed carefully as all significant values less than 130 ml were

considered in the repeatability standard (≤150 ml) for FVC and FEV₁ measures (M.R. Miller et

al., 2005).

To try to rule out fitness status (VO2max) as the limit of performance improvement in this

study, VO2max was plotted against changes in performance time. The data show a lack of

relationship between these variables.

Given the limitations in this study, the following improvements should be considered: The

subject population consisting of healthy young males with no prior breathing challenges showed

a lack of significant improvement in perceived breathing for the condition (CC and IEC) and both

running. Furthermore, the perception of these subjects about breathing during rest, activity, and

recovery may be less sensitive because they tend to recover rather quickly because they only

experience breathing challenges during high-intensity exercise. Second, the use of recovery PFT

measures to determine statistical differences in seemingly healthy young men after exercise may

not be sensitive enough to detect the immediate effects of respiratory warming. Use of breath-by-

breath analysis to track trends in total respiratory rate and tidal volume during exercise; as well as

the exercise flow volume loop, perhaps a more precise measuring tool. Conversely, the breathing

challenges created by changes in the structure of the respiratory system (mouth pieces, nose clips,

and total mouth breathing) may be able to disguise anything

positive changes caused by warming up the respiratory system. Finally, the possibility that the

number of subjects in this study could undermine statistical reliability can never be discarded.

A possible future study is to consider diverse populations of subjects, those with previous

respiratory challenges (asthmatics, chronic obstructive pulmonary disease, the elderly, and

congestive heart failure) who might benefit from the studied respiratory warming. Use a more

sensitive way to measure the variables being tested (breath-by-breath test as one of the possible

tools). And finally, attention should be paid to the evaluation of respiratory warm-up on more

specific modalities (i.e. swimming, cycling, skiing, and/or running 400 meters) need to be

considered.

Conclusion. In exploring new ways to improve performance during activities where

breathing can limit exercise, it is understood that warming up the respiratory system before

exercise can indeed improve performance. The findings from the study showed a 3.2%

improvement in performance time in a 1.5-mile run that incorporated warm-up treatments.

Although this increase may not be seen as a major modification, when one considers the

estimated respiratory costs on the system of up to 14-16% of VO2max and cardiac output in

highly trained individuals (Aaron et al., 1992; Harms, McClaran, et al., 1998) became clear that

any benefit could be appreciated. Miller et al. (2006) suggest that improved performance can be

explained by reduced perception of secondary dyspnea due to reduced respiratory muscle work.

The evidence presented in this study shows the benefit of warming up the respiratory system

directly before exercise performance; The mechanism can be explained by reduced perception

of dyspnea, reduced work of the respiratory muscles, thus resulting in an increase in

performance. Secondary mechanisms can be explained by priming

The respiratory system as seen in the traditional warming modality triggers the skeletal and

circulatory systems as previously reviewed by many authors.

2.4 Eksperimen 4

Introduction. Many exercise physiologists believe that the respiratory system has little or

no effect on limiting exercise performance in healthy individuals or athletes (A. McConnell,

2009), but the respiratory system faces some challenges during intensive exercise. One example

is the partial alveolar pressure regulation of oxygen and carbon dioxide achieved by a considerable

increase in alveolar minute ventilation (VE), often 20 times the resting value in humans. This

large increase in VE is achieved by the capacity of the respiratory muscles to not only produce

alveolar ventilation strength but also by limiting excessive physiological costs on the system

during exercise (Guenette & Sheel, 2007). Another example that challenges the respiratory system

to address is the ability of the bronchial airways (intra-thoracic) to maintain patency to allow for

the increased flow rate required during active expiry often seen in intense exercise. During high-

intensity exercise, the bronchial airways sometimes present significant limitations on expiratory

flow; therefore, it causes dynamic hyperinflation, increased work of respiratory muscles, and

limitation of VE (Forster et al., 2012).

An often overlooked ingredient for possible limitations of the respiratory system is how

the mechanical workings of breathing have sensory and metabolic impacts. Perceived breathing

work contributes to how hard the exercise feels (sensory) and the demands of the mechanical

work of breathing places on the circulatory system for blood and oxygen to maintain muscle

contraction (metabolic) (A. McConnell, 2009). It has been suggested that the metabolic and

circulatory costs of high mechanical respiratory work during maximum levels of VE can amount

to 8-10% of VO2max (maximum oxygen consumption) and cardiac output in

untrained individuals and up to 14-16% VO2max and cardiac output in highly trained individuals

(Aaron et al., 1992; Harms, McClaran, et al., 1998). It is further noted that, with studies on the

distribution of blood flow, when the respiratory muscles are loaded, vasoconstriction reflexes are

produced which results in a decrease in blood flow to the exercising limbs. Conversely, when the

respiratory muscles are dismantled, a state of increased blood flow (dilation) exists in the muscles

of the legs that are exercising (Harms, Wetter, et al., 1998). This change in limb blood flow

suggests a competitive relationship between the motor muscles and the respiratory muscles for

limited cardiac output (Guenette & Sheel, 2007). These findings may represent the respiratory

system's challenge to maintain airway patency in the face of maximum or near-maximum

workload, creating high VE demands, competition for available cardiac output with limb muscles,

and variation in respiratory muscle fatigue states.