title: Predictors of Physical Activity among Adolescent Girl Students Based on the Social Cognitive Theory.
abstract: 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.
authors.affiliation: Department of Health Education and Health Promotion, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Monasadat
authors.initials: M
authors.lastname: Ardestani
authors.affiliation: Department of Health Education and Health Promotion, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. niknamis@modares.ac.ir.
authors.forename: Shamsaddin
authors.initials: S
authors.lastname: Niknami
authors.affiliation: Department of Health Education and Health Promotion, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Hidarnia
authors.affiliation: Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Hajizadeh
mesh_terms: D000293:Adolescent; D003071:Cognition; D003430:Cross-Sectional Studies; D015444:Exercise / Q000523:psychology*; D005260:Female; D005544:Forecasting; D015438:Health Behavior; D006293:Health Promotion / Q000379:methods* / Q000639:trends*; D006801:Humans; D007492:Iran; D008019:Life Style; D009042:Motivation; D020377:Self Efficacy; D013334:Students / Q000523:psychology*; D011795:Surveys and Questionnaires
keywords: Physical activity; Regression analysis; Students