kinesiology

Methods

Participants were eighth-grade students sampled from a middle school in the southwestern United States. Participants (N = 63, 57 boys, 6 girls, mean age 13.7 +/- 0.5 years) were asked to provide written assent in conjunction with written consent from a parent or legal guardian. Participants were all apparently healthy as defined by their enrollment in PE class, and able to participate in regular exercise. No other inclusion or exclusion criteria was applied. The study was conducted in accordance with American College of Sports Medicine (ACSM) ethical guidelines and following the rules of the Declaration of Helsinki. Institutional Review Board approval was granted by the University of Utah (IRB_00061661) and the Salt Lake City School District. Comment by Andrew Harveson: This first paragraph could likely have the sub-heading “participants.” Note the description of demographic characteristics, inclusion criteria, and human subjects protection.

To test academic achievement, four 10-question math tests were conducted, with questions taken from the New York State Testing Program eighth-grade standardized exams [13]. Similar tests have been used in previous research [14] and the tests used in the present study had been shown to be reliable and valid, containing internal consistency coefficients of r = 0.85. Reliability data were not available for mathematics tests in the state where data collection took place, thus, out-of-state exams were used. Eighth-grade mathematics teachers at the site of data collection were consulted to confirm that material on the proposed mathematics tests had been covered during the same school year. To prevent a practice effect, different questions were used for each test. Participants had to complete each 10-question test within five minutes to provide a realistic classroom setting. Cognition was measured using the Stroop Test (Victoria version). The Victoria version of the Stroop Test has been used to determine executive function and selective attention using three increasingly challenging tasks (Dot, Word, and Color tests) performed in quick succession [15], and is commonly used in research with participants ranging from children to adults. Participants were progressively required to name colored dots (Dot test), words printed in the same color as dots (Word test), and finally color words printed in non-corresponding colors (Color test). Each task contained 24 items and challenged participants to deal with an interference effect, which can slow reaction time. Comment by Andrew Harveson: Paragraph #2 is a description of the research instruments, their suitability for use in the study.

Participants were required to perform one familiarization session on the mathematics test, Stroop test, and exercise protocols during regularly scheduled PE classes. After a period of seven days, the students were separated into three experimental exercise sessions, aerobic exercise, resistance exercise, and non-exercise, which rotated each week for three weeks in a randomized crossover design. Experiment conditions were varied to avoid an order effect. Previous research has shown that the beneficial effects of exercise on executive function, as measured by event-related brain potential, peaks within 40 minutes [16], thus, the tests of mathematics and cognition were administered between 5 and 20 minutes after each exercise session. The authors also felt that such a time-span following acute exercise would best mimic what would be seen in authentic classroom settings where exercise might be used to boost academic performance. The primary author and trained research assistants collected data. Comment by Andrew Harveson: Paragraphs 3 and 4 describe the procedures and protocols that were followed to collect data. Note the use of previous research to support and strengthen the design.

Previous work by Alves et al. [7] laid the groundwork for the aerobic and resistance exercise protocols used in this study, which were designed to elicit moderate intensity activity levels. The resistance exercise protocol involved six exercises, and participants completed two sets of 15 repetitions in each of the following: squat, lunge, pushup, band pull down, band row, and overhead press. Weight was reduced or exercises were modified if participants were unable to complete 15 repetitions per set [17]. The complete resistance exercise session was 20 minutes long, with one-minute rest breaks between sets. The aerobic exercise intervention was likewise composed of 20 minutes of walking or jogging around an indoor track at approximately 50-60% of the participants’ age-predicted heart rate maximum. The non-exercise control group consisted of participants viewing a sports-related DVD for 20 minutes. To ensure that participants remained inactive, seated, and did not fall asleep, students were monitored by the primary author, trained research assistants, and classroom teachers, in accordance with prior research protocols [17]. Exercise intensity was monitored immediately following each set of resistance exercise and at five minute intervals during the aerobic exercise intervention, using Borg’s original Rating of Perceived Exertion (RPE) scale [18].

Repeated measures analysis of variance (ANOVA) was used to determine whether differences existed among the treatments. An alpha of 0.05 was used to determine statistical significance. All analysis was completed using SPSS 22.0. Comment by Andrew Harveson: The final paragraph describes the statistical analysis that will be performed in order to determine results.