A social ecological analysis of physical activity promotion for overweight and normal weight youth
Introduction. The psychosocial correlates of youth physical activity have not been well scrutinized in the context of the relatively new phenomenon of an increased prevalence of overweight among youth. The purpose of the examination of unique subpopulations (rural vs. urban; overweight vs. normal overweight) within a psychosocial and social ecological framework, was to enhance the theoretical basis for designing improved physical activity interventions for youth. Methods. Data were from a large cohort of Iowa youth, ages 9--11 and 14--18 years (N = 2,862). Physical fitness, body composition, height and weight were assessed. Students completed a physical activity questionnaire, the Childrens' Physical Activity Correlates Survey and the Children and Youth Physical Self-Perception Profile (CY-PSPP). The Youth Physical Activity Promotion model (Welk, 1999) was used as a framework to examine physical, social ecological, enabling, predisposing, and reinforcing influences on youth physical activity. Results. Prevalence of overweight was higher among rural children (25%; p < .001) than children from more urban areas (18%). Among girls, being overweight was associated with reduced global self-esteem, attraction to physical activity, and parental influence. Perceived physical activity competence did not vary appreciably by weight status, except for among adolescent girls. The largest differences between overweight and normal weight youth were lower physical self-perceptions of adolescent girls and boys (Cohens' d = 0.74--1.16). The Youth Physical Activity Promotion model showed good fit to the data and provided parsimony in the evaluation of physical activity while still accounting for a significant amount of variance in physical activity (R2 = .33). Within the model, BMI showed a very small direct effect on physical activity, but did not show effects on the correlates of physical activity. Conclusions . The largest differences in psychosocial correlates of physical activity associated with weight category were in physical self-perceptions, yet BMI showed minimal influence on a model of youth physical activity promotion. The results suggest that parental reinforcement, perceived competence, and attraction to physical activity should be promoted for both overweight and normal weight youth.