The relationship between self-determined motivation and physical activity in adolescent boys

Background: Physical education (PE) lessons and leisure-time represent two important opportunities for adolescents to accumulate moderate-to-vigorous physical activity (MVPA). Purpose: Framed by self-determination theory, this study investigated how much of the observed variation in adolescent boys' MVPA levels (during PE and leisure-time) was explained by individual- and class-level motivation. Methods: Cross-sectional design. Adolescent boys (N ¼ 61, M ¼ 14.36 years, SD ¼ .48 years) completed motivation questionnaires and wore an accelerometer during a PE lesson and across 7 consecutive days. Results: Self-determined motivation toward PE predicted MVPA during PE lessons (R2 ¼ .31). Self-determined motivation toward leisure-time physical activity was positively associated with MVPA during leisure-time (R2 ¼ .08). Conclusions: Findings support the tenets of self-determination theory and suggest that motivation may be an important correlate of adolescent boys' MVPA in PE lessons and during leisure-time. Also, results indicated that teachers' behavior may be an important determinant of MVPA in PE lessons, while individual motivation may be more important in leisure-time.