Objective: To test the hypothesis that third grade children (mean age = 8.7, SD = 0.5) who attended an 8‐month after‐school program would exhibit favorable changes in body composition, cardiovascular fitness, blood pressure, total cholesterol, and high‐density lipoprotein‐cholesterol compared with children in control condition.Research Methods and Procedures: Subjects were 61% African‐American, 31% white, and 8% other racial background from 18 public schools. Sixty‐eight percent were eligible for free or reduced price lunch. Percentage body fat and bone mineral density were assessed by DXA, cardiovascular fitness by heart rate response to a step test, resting blood pressure with a Dinamap, and non‐fasting total cholesterol and high‐density lipoprotein‐cholesterol by finger stick. Data pre‐ and post‐intervention were available for 447 children. Children in the nine intervention schools who attended at least 40% of the after‐school sessions were compared with control subjects.Results: Compared with the control subjects and after controlling for race, sex, free/reduced price lunch status, and school‐level covariates, youths in the intervention group showed a relative reduction of percentage body fat [−0.76 (95% confidence interval (CI), −1.42, −0.09)], a greater relative gain in bone mineral density [0.008 (95% CI, 0.001, 0.005)], and a greater relative reduction in heart rate response to the step test [−4.4 (95% CI, −8.2, 0.6)]. The other outcome variables showed non‐significant trends in favor of the intervention subjects.Discussion: These results are promising in light of the potential impact on the emerging childhood obesity epidemic. The Medical College of Georgia FitKid Project has the potential to be institutionalized because it is built on the existing infrastructure in most public schools in the U.S.

Children tend to be sedentary during the after-school hours, and this has deleterious effects on their health. The objective of the present study was to determine the effects of a 3-year after-school physical activity (PA) program, without restriction of dietary energy intake, on percent body fat (%BF), cardiorespiratory fitness (CRF), and cardiometabolic markers in children. A cluster randomization design was employed. A total of 574 3rd grade children from 18 elementary schools in the southeastern United States participated. The intervention consisted of 80 minutes of age-appropriate moderate-to-vigorous PA each school day. The main outcomes of interest were %BF measured by dual-energy X-ray absorptiometry; CRF measured by heart rate in response to a submaximal step test; nonfasting total and high-density lipoprotein cholesterol (HDL-C); and resting blood pressure (BP). Intent-to-treat analyses showed significant treatment by time interactions for %BF (p = 0.009) and CRF (p = 0.0003). The change pattern of the means suggested that %BF and CRF in intervention children improved relative to control children during the school months, rebounding to the levels of control children over the summers following years 1 and 2. Year-by-year analyses of what occurred during the months when the program was offered revealed dose–response relations for %BF and CRF, such that the clearest beneficial effects were seen for those youth who attended at least 60% of the after-school sessions. No significant intervention effects were seen for cholesterol or BP. An after-school PA program was effective in reducing adiposity and improving CRF, especially in the children who attended the sessions at least 3 days/week. However, the favorable effects on %BF and CRF were lost over the summer. Thus, it is critical to incorporate strategies that attract and retain the children to receive an adequate dose of PA year-round.

Background:The moderating effect of physical activity (PA) on relations between chronic stress and adiposity is unknown in youth.Purpose: The objective is to assess the mediating effect of PA on relations between stress and adiposity in youth.Methods: Participants were 303 youths (47% Black,53%White,50%male, M age = 16.6 years). The Adolescent Resource Challenge Scale assessed personal stress, whereas median rent or mortgage in the neighborhood reflected community stress. Body mass index (BMI) and sum of skinfolds reflected general adiposity, and waist circumference measured central adiposity. Days per week performing PA sufficient to work up a sweat measured PA.Results: Hierarchical regressions predicted each adiposity measure adjusting for age, race, gender, family socioeconomic status, and parental smoking. Independent contributions of personal stress, but not community stress, were found on BMI and sum of skinfolds. A similar model showed that both personal and community stress predicted waist circumference. PA was independently, inversely associated with sum of skinfolds but not BMI or waist circumference. The interaction between PA and personal stress predicted all three adiposity measures. The interaction of PA with community stress predicted BMI.Conclusions: PA appears to buffer the effects of chronic stress on adiposity, providing evidence that PA is a protective factor for health.

The prevalence of obesity increased while certain measures of physical fitness deteriorated in preschool children in China over the past decade. This study tested the effectiveness of a multifaceted intervention that integrated childcare center, families, and community to promote healthy growth and physical fitness in preschool Chinese children.

Objective: To investigate the relations of attendance of children in an after-school physical activity (PA) program to changes in body composition and cardiovascular fitness (CVF). Design: Eight-month after-school PA-based intervention. Subjects: In all, 278 third-grade boys and girls from nine elementary schools (age, 8.7 y (s.d.=0.6 y), body mass index (BMI) 19.1 kg/m² (s.d.=4.4) and percent body fat (%BF) 26.0 (s.d.=9.0)). Measurements: Body composition (from dual-energy X-ray absorptiometry), BMI (from height and weight), waist circumference (WC) and CVF (from the YMCA submaximal bench-stepping test). Results: There was a significant negative linear trend between level of attendance in the after-school program and change in %BF and fat mass; there was also a significant positive linear trend between program attendance and change in CVF. There was a marginally significant linear trend between program attendance and fat-free mass. Greater increases in bone mineral density were observed with higher program attendance. Changes in BMI and WC were not influenced by program attendance. Conclusion: Understanding the dose–response effect of PA on health outcomes, particularly body composition, in children is crucial in our effort to prevent overweight and its health consequences. Since there is limited data available to base PA dose recommendations for youths, findings from this study are relevant, and suggest that greater health benefits can be obtained in young children with more frequent participation in PA.