assessment of the efficacy of physical activity level and lifestyle behavior interventions applying social cognitive theory for overweight and obese girl adolescents

Background: childhood obesity has become a global epidemic and physical inactivity and considered as one of the most important contributing factors. we aimed to evaluate a schoolbased physical activity intervention using social cognitive theory (sct) to increase physical activity behavior in order to prevent obesity among overweight and obese adolescent girls. study design: randomized controlled trial study. methods: a sevenmonth randomized controlled trial based on sct was implemented with 172 overweight and obese girl students (87 in intervention and 85 in control group), with the presence of their parents and teachers. activities of the trial included: sports workshops, physicalactivity consulting private sessions, free practical and competitive sports sessions, family exercise sessions, text messages, and newsletters. body mass index (bmi) and waist circumference (wc) were measured and questionnaires about duration of physical activity, duration of screen time (watching television and playing computer games) and psychological variables regarding the sct constructs were obtained. results: duration of physical activity (in minutes) and most of psychological variables (selfefficacy, social support, and intention) significantly increased at postintervention, while hours of watching television and playing computer were significantly decreased (p<0.001). the subjects’ mean bmi and wc reduced in the intervention group from 29.47 (4.05) kg/m2 to 28.5 (4.35) kg/m2 and 89.65 (8.15) cm to 86.54 (9.76) cm, although they were not statistically significant compared with the control group (p=0.127 and p=0.504, respectively). conclusions: schoolbased intervention using sct led to an increase in the duration of physical activity and reduction in the duration of screen time in overweight and obese adolescent girls.