Abstract
The purpose of this study was to explore the relative contributions of various types of perceived parent and physical education teacher social support to adolescent leisure-time physical activity motivation and behavior within the framework of self-determination theory (SDT; Deci & Ryan,2000). In line with SDT, it was hypothesized that greater perceptions of autonomy support, involvement and modeling would positively relate to physical activity behavior and that these relationships would be mediated by self-determined motivation. Middle school students (N = 161) completed a paper survey during their physical education class which assessed the study variables. Structural equation modeling was used to test three models (one model for each type of social support) that specified the mediating role of self-determined motivation in the relationship between social support variables and physical activity behavior. In the models, each parent and physical educator social support variable had a significant, positive, direct relationship to self-determined motivation and indirect relationship (mediated by self-determined motivation) to physical activity behavior, which were of similar magnitude. The findings suggest that mothers and fathers both have significant roles in their adolescent's leisure-time physical activity motivation and that physical educators, although not present in the leisure-time physical activity context, serve an equally important role in supporting adolescents' leisure-time physical activity. Additionally, adolescent self-determined motivation for leisure-time physical activity seems to be a strong determinant of self-reported leisure-time physical activity behavior.
