Mediators affecting girls' levels of physical activity outside of school: findings from the trial of activity in adolescent girls.

BACKGROUND: Providing after school activities is a community level approach for reducing the decline in physical activity of girls as they reach early adolescence.

PURPOSE: The purpose of this study was to examine psychosocial, environmental, and behavioral factors as potential mediators of after school physical activity in adolescent girls.

METHODS: We assessed objectively measured levels of physical activity occurring outside of school and potential predictors and mediators of activity in girls participating in the Trial of Activity in Adolescent Girls (TAAG).

RESULTS: We found that the TAAG intervention had a statistically significant and positive effect on out of school activity in the 2006 cohort. Self-efficacy, friends' social support, total social support, and difficulty getting to and from community activities mediated the level of moderate to vigorous physical activity in girls.

CONCLUSIONS: Parents, communities, and schools should provide and enhance opportunities outside of the school day for adolescents to be active. Reducing transportation barriers and enlisting social support appear to be key.