To determine the effects of epoch length and activity count cutpoints on ActiGraph (AG; ActiGraph Health Services, Pensacola, FL) accelerometer estimates of time in moderate-to-vigorous physical activity (MVPA) in fifth-grade children monitored during physical education (PE) compared with a direct observation (DO) criterion standard. A sample of 32 fifth-grade males and females (mean age = 10.3 +/- 0.5 yr) wore an AG attached at the waist for a 30-min PE class. Participants were concurrently videotaped, and the Computerized System for Observing Fitness Instruction Time (C-SOFIT) was used to create a DO measure of MVPA time (DO_MVPA). AG data were collected in 5-s epochs then integrated into 10-, 15-, 20-, 30-, and 60-s epochs. AG activity counts were converted into time (in s) in MVPA using validated (and epoch-adjusted) children's activity count cutpoints established by Treuth et al. (AG_T), Mattocks et al. (AG_M), and Freedson et al. (AG_F). All AG_T and AG_M epoch detected significantly lower time in MVPA than DO_MVPA. The percentage of DO_MVPA detected by AG_T and AG_M epochs ranged from 46% to 61% and from 26% to 47%, respectively. All AG_F epochs yielded similar (i.e., nonsignificant) mean estimates of MVPA versus DO_MVPA, with modest increases in root mean squared error (RMSE) with increasing epoch length. The percentage of DO_MVPA detected by AG_F epochs ranged from 93% to 100%. All AG_F epoch lengths provide comparable mean estimates to DO-detected MVPA time in fifth-grade children during PE. To minimize error among individual estimates, shorter epoch lengths should be used, with 5-s epochs yielding the lowest RMSE in the current study. Considerations of both epoch length and activity count cutpoint are important to improved detection of intermittent bouts of MVPA among fifth-grade children.

Background: The purpose of this study was to examine the effect of a Comprehensive School Physical Activity Program (CSPAP) on physical activity and health-related fitness (HRF) in children from low-income families.Methods: Participants included 1390 children recruited from kindergarten through sixth grade (mean age = 8.4 ± 1.8 years). Physical activity measures were collected at baseline and at 6 weeks and 12 weeks after program implementation, and HRF measures were collected at baseline and at 12 weeks after program implementation.Results: There were significant but weak-to-moderate increases in step counts (mean difference = 603.1 steps, P < .001, d = 0.39) and moderate-to-vigorous physical activity (mean difference = 4.9 minutes, P < .001, d = 0.39) at 12 weeks compared with baseline. There were also significant but moderate increases in Progressive Aerobic Cardiovascular Endurance Run laps (mean difference = 6.5 laps, P < .001, d = 0.47) at 12 weeks compared with baseline. Generalized mixed models respectively yielded 3.02 and 2.34 greater odds that a child would achieve step count and moderate-to-vigorous physical activity standards and 2.26 greater odds that a child would achieve aerobic fitness standards at 12 weeks compared with baseline (P < .001).Conclusions: The 12-week CSPAP improved physical activity and HRF in children from low-income families; however, the magnitude of the effects was weak to moderate.

Over the past 3 decades, public health professionals have worked to stem the rising childhood obesity epidemic. Despite the field’s best efforts, no progress has been made in reducing child obesity. One reason for this failure may be that obesity prevention and treatment efforts have predominately been delivered during the 9-month school year. However, recent evidence suggests that the summer, not the school year, is when unhealthy changes in body composition (ie, accelerated increases in percent body fat) and fitness losses occur. This unhealthy change in body composition and fitness loss during the summer could be explained by the “Structured Days Hypothesis,” which posits that children engage in a greater number of unhealthy obesogenic behaviors on unstructured days when compared with structured days. Furthermore, the summer may be contributing to a widening “health gap” between children from low-income and middle- to upper-income families. During summer, fewer opportunities exist for children from low-income households to access healthy structured programs that do not require fees for participation. Moving forward, public health professionals should prioritize efforts to mitigate unhealthy changes in body composition and fitness loss during the summer by identifying ways to provide access to structured programming during this timeframe for children from low-income households.

High levels of physical inactivity are evident among many American children. To address this problem, providing physical activity (PA) during the school day within the CSPAP framework, is one strategy to increase children’s PA. Thus, the purpose of this study was to examine the effects of a classroom-based PA program on children’s PA. Two hundred and ten students from one school participated in TAKE 10! for 12 weeks. All students wore pedometers and a sample of 64 students wore accelerometers for 4 days during week 1 (baseline), week 8 (midintervention), and week 12 (end-intervention). Data were analyzed using repeated-measures ANOVA. The results showed that students’ daily in-school step counts increased by 672 steps from baseline to midintervention (P < .001). Students’ moderate-to-vigorous intensity PA (MVPA) increased by approximately 2 minutes from baseline to end-intervention (P < .01). In conclusion, participating in TAKE 10! helps children strive toward the goal of recommended daily MVPA.

The purpose of this study was to examine the effect of a 12-week resistance training programme on fat-free mass (FFM), muscle cross-sectional area, muscular strength and muscle quality in women who underwent Roux-en-Y gastric bypass surgery. Participants were 16 women (mean age = 44.9 ± 10.2 years) from bariatric surgical groups who were randomly assigned into either a control or an intervention group. Air displacement plethysmography measured FFM and magnetic resonance imaging measured quadriceps muscle cross-sectional area and whole thigh muscle cross-sectional area. Muscular strength and quality was assessed using an estimated 1-Repetition Maximum assessment. All measurements were collected twice, at baseline and at a 12-week follow-up. There were significantly greater improvements in leg press strength (mean differences = 55.4%, P < 0.001, Cohen’s d = 2.4), leg extension strength (mean differences = 18.0%, P = 0.014, Cohen’s d = 0.86) and leg press muscle quality (mean differences = 54.5%, P < 0.001, Cohen’s d = 1.9) in the intervention group compared to the control group following the resistance training programme. The resistance training intervention significantly improved muscular strength and quality; however, it did not illicit changes in FFM or muscle cross-sectional area in women who underwent Roux-en-Y gastric bypass surgery.

Background: The need to understand where and how much physical activity (PA) children accumulate has become important in assisting the development, implementation, and evaluation of PA interventions. The purpose of this study was to describe the daily PA patterns of children during the segmented school-week.Methods: 829 children participated by wearing pedometers (Yamax-Digiwalker SW-200) for 5 consecutive days. Students recorded their steps at arrival/departure from school, Physical Education (PE), recess, and lunchtime.Results: Boys took significantly more steps/day than girls during most PA opportunities; recess, t(440) = 8.80, P < .01; lunch, t(811) = 14.57, P < .01; outside of school, t(763) = 5.34, P < .01; school, t(811) = 10.61, P < .01; and total day, t(782) = 7.69, P < .01. Boys and girls accumulated a similar number of steps t(711) = 1.69, P = .09 during PE. For boys, lunchtime represented the largest single source of PA (13.4%) at school, followed by PE (12.7%) and recess (9.5%). For girls, PE was the largest (14.3%), followed by lunchtime (11.7%) and recess (8.3%).Conclusion: An understanding of the contributions of the in-school segments can serve as baseline measures for practitioners and researchers to use in school-based PA interventions.