The relationship between psychosocial correlates and physical activity in underserved adolescent boys and girls in the ACT trial

Background: Previous research suggests motivation, enjoyment, and self-efficacy may be important psychosocial factors for understanding physical activity (PA) in youth. While previous studies have shown mixed results, emerging evidence indicates relationships between psychosocial factors and PA may be stronger in boys than girls. This study expands on previous research by examining in the effects of motivation, enjoyment, and self-efficacy on PA in underserved adolescents (low income, ethnic minorities) boys and girls. Based on previous literature, it was hypothesized the effects of motivation, enjoyment, and self-efficacy on moderateto- vigorous PA (MVPA) would be stronger in boys than in girls. Methods: Baseline cross-sectional data were obtained from a randomized, school-based trial (Active by Choice Today; ACT) in underserved 6th graders (N = 771 girls, 651 boys). Intrapersonal variables for PA were assessed via self-report and confirmatory factor analyses were conducted for each predictor. MVPA was assessed with 7-day accelerometry estimates. Results: Multivariate regression analyses stratified by sex demonstrated a significant positive main effect of self-efficacy and motivation on MVPA for girls. Boys also showed a positive trend for the effect of motivation on MVPA. Conclusions: The results from this study suggest motivation and self-efficacy should be better integrated to facilitate the development of more effective interventions for increasing PA in underserved adolescents.