Motivational processes in physical education and objectively measured physical activity among adolescents

Purpose:Grounded in self-determination theory(SDT),the present study tested how students’perceptions of autonomy support from physical education teachers predicts objectively measured moderate-to-vigorous physical activity(MVPA)of adolescents.According to SDT,it was expected that psychological needs and autonomous and controlled forms of motivation would mediate these relationships.Methods:Students(n=397)aged from 11 to 15 years in 17 different schools filled in questionnaires regarding SDT variables.In addition,objective MVPA was measured using an accelerometer(ActiGraph GT3X;ActiGraph,Pensacola,FL,USA)for 7 days.Structural equation modelling was used to examine the hypothesized relationships among the study variables.Results:The theory-based model showed a good fit with the data:x2=642.464,df=257;comparative fit index=0.932;non-normed fit index=0.921;root mean square error of approximation=0.062;root mean square error of approximation 90%confidence interval:0.054
0.067.As hypothesized,there was a significant and positive direct relationship between autonomy support and need satisfaction(b=0.81,p=0.001).In turn,need satisfaction positively predicted intrinsic motivation(b=0.86,p=0.001).Intrinsic motivation was positively related to MVPA(b=0.29,p=0.009).A significant indirect effect(b=0.20,p=0.004)supported the mediating role of psychological need satisfaction and intrinsic motivation in the relationship between perceived autonomy support and objectively measured MVPA.Conclusion:The findings of the current study support the applicability of the SDT-based model in explaining the antecedents of objectively measured MVPA of adolescents.To enhance adolescents’daily MVPA,special focus should be put on increasing their intrinsic motivation toward physical education.