Physical Activity Behavior

Regular physical activity has been considered as an essential part of a healthy lifestyle. Inactivity result in the increase of various diseases such as obesity1,2. And so physical activity has positive effect on educational outcomes for school students. For example, enhanced math’s marks, better consideration in the classroom3. Despite this awareness, lots of children and adolescents keep consistently on high levels of sedentariness and low levels of regular physical activity; these trends are exaggerated for females4,5. National surveys and reviews show that the prevalence of insufficient PA was different from 18.7% to 90.6%, with a median of 79.7%. In all studies, the higher inactivity was shown among girls than boys and so in the developing

Sedentary behaviors have a major health concern worldwide, hence increase in RPA could improve health substantially8. It is slight known about the determinants of physical activity behaviors of Iranian school students. Therefore, it is important to understand physical activity behaviours of particular societies. Limited theory based studies have recognized the predictors of physical activity behaviour among Adolescents9 . One of the appropriate theories for analytical behaviour change is the Transtheoretical Model (TTM)10, which has been effectively used to describe a variety of health behaviours, including physical activity11-13. The TTM contains five stages of exercise behavior change, 10 constructs for processes of change, pros and cons and self-efficacy14,15. The five stages consist of: (1) pre-contemplation (PC) in which individuals are not thinking of exercise in the next six months, (2) contemplation (C) in which individuals are thinking of exercise in the next six months, (3) preparation (P) in which individuals are thinking of taking action in the next month, (4) action(A) in which persons have been regularly active for less than six months, and (5) maintenance(M) in which persons have continued regular exercise for more than six

This questionnaire measure cognitive and behavioral processes of change by 30 questions. The students recalled the past month and answered each of questions with choosing the five-point Likert scale rated from 1(never) to 5 (repeatedly). The questionnaire has showed acceptable reliability and stability in previous studies (α = 0.86, ICC = 0.90). (nigg, farmanbar ). In this study, the internal consistency of the questions was good (α = 0.83 for both cognitive and behavioral process). factor analysis was done in order to make a factor relationship matrix of the revised questionnaire, and a total 28 items were finally used in this study as a tool for evaluating processes of exercise behavior change among Iranian adolescents.

Exercise Self-Efficacy Scale, The short form Exercise Self-Efficacy Scale established by (Benisovich) was translated and used in this study. This scale measures how confident persons to exercise when other things get in the way. The scale contains six items ranked on 5-point Likert scales from 1(not at all confident) to 5(completely confident). The internal consistency questions were (α = 0.71,