Effects of a standardized curriculum on physical activity and body composition in after-school program participants with BMI scores above the 90th percentile: Assessing theory-based predictors

Abstract

Childhood overweight and obesity is a continued problem. Children above the 90th percentile for BMI are particularly susceptible to cardiovascular health risks. There remains a minimal understanding of theory-based psychological predictors of physical activity and weight change in children. This research incorporated data from a subsample of afterschool care enrollees above the 90th BMI percentile (Mage=10.1 years) who participated in either 4-day/week (n = 21) or 3-day/week (n = 24) versions of a 45 min/session, cognitive-behaviorally based physical activity/health behavior-change program over a full school year, or a control condition of usual care (n = 14). For the cognitive-behavioral groups only, significant improvements were found in self-regulation, mood, and physical activity. Their BMI increases of 0.12 and 0.11 kg/m2, respectively, were significantly less than the 0.90 kg/m2 rise expected through maturation. Theory-based regression models uniformly confirmed significant associations of changes in self-regulation and physical activity (R2s = .22-.25). However, within separate analyses, entry of changes in (a) self-efficacy and mood into a multiple regression equation, (b) self-efficacy as a mediator, and (c) mood as a moderator, did not increase predictive accuracies. The significant association of changes in physical activity and BMI was stronger in the heavier children. Findings will be useful for large-scale intervention applications and refinements.