predictors of physical activity among adolescent girl students based on the social cognitive theory

background: the importance of increasing adolescence girl’s level of physical activity is recognized as a priority for having a healthy lifestyle. however, adolescent girls especially iranian, are at high risk for physical inactivity. social cognitive theory (sct) is a successful theory to explain physical activity behavior. the aim of this study was to determine the predictors of physical activity based on the sct. methods: this cross-sectional study was conducted among 400 adolescent girls (15-16 yr old) in tehran, iran (2013). the participants were randomly chosen with multistage sampling. the sct constructs consisted of self-efficacy, self-regulation, social support, outcome expectancy, and self-efficacy to overcoming impediments. statistical analysis was carried out applying spss: 16, lisrel 8.8. stepwise regression was used to test predictors of behavior. pearson correlation was assessed. results: self efficacy to overcoming impediments was the main construct to predict physical activity (beta=0.37). other determinants were self-efficacy (beta=0.29), family support (beta=0.14), outcome expectancy (beta=0.13), friend support (beta=0.12), and self-regulation (beta=0.11), respectively. in general, the sct questionnaire determined 0 . 85 variation of physical activity behavior. all of the constructs had direct significant relation to physical activity behavior ( p <0.001). conclusions: the constructs of sct provide a suitable framework to perform promoting physical activity programs and self-efficacy to overcoming impediments and self-efficacy are the best predictors of physical activity in adolescent girls.