Motivation for Physical Activity among U.S. Adolescents: A Self-Determination Theory Perspective.

BACKGROUND Promoting adolescent physical activity is crucial as this marks a time when physical activity rates decline. PURPOSE This study examined motivation for physical activity from a self-determination theory (SDT) perspective in a large sample of adolescents in the USA across three settings: in school, out of school, and on weekends. METHODS Participants (N = 1,661) were adolescents from the National Cancer Institute's Family Life, Activity, Sun, Health, and Eating study. Participants had a mean age of 14.47 (standard deviation = 1.61) and were 50.2% female. In this national sample balanced to match the U.S. population on several key demographics, 64.2% were non-Hispanic White. Analyses included three linear regression models in which estimated weekly minutes of moderate-to-vigorous physical activity (MVPA) in school, out of school, and on weekends were entered as dependent variables. Five forms of motivation (intrinsic, integrated, identified, introjected, and external) were entered simultaneously as independent variables. Age, body mass index, gender, and race/ethnicity were also included as covariates. RESULTS All models were significant. For MVPA in school, external regulation, introjected regulation, identified regulation, and intrinsic motivation were positively associated with MVPA. For MVPA out of school, external regulation, introjected regulation, identified regulation, integrated regulation, and intrinsic motivation were positively associated with MVPA. For MVPA on weekends, integrated regulation, and intrinsic motivation were positively associated with MVPA. CONCLUSIONS The relationship between motivation and MVPA varies across settings. These findings have important implications for motivating adolescents to engage in physical activity and may inform future interventions aimed at increasing physical activity.