摘要：Background: Identifying the factors that affect adolescents’ participation in physical activity is considered as an important topic concerning public health.Objectives: The purpose of the present study was to test the effects of the constructs of the planned behavior theory on the physical activity behaviors of beginner Volleyball adolescent students. Methods: We used a descriptive-correlational approach in the present study. The participants comprised 112 middle school students from Urmia, Iran, 2020. The Research was conducted on the basis of the Theory of Planned Behavior, and the physical activity behaviors were objectively measured by the use of an accelerometer. To analyze the data, we used the structural equation method.Results: Results showed that attitude and perceived behavioral control had significant impacts on the intention to physical activity (both T>1.96). However, no significant effect was observed for the subjective norm on intention to physical activity (T=0.152). Moreover, intention to physical activity significantly affected the moderate-to-vigorous physical activities (T>1.96). Finally, attitude and perceived behavioral control had significant effects on moderate-to-vigorous physical activities through a mediation by intention to physical activity (all P<0.001). The daily MVPA was 45.48 minutes, which is below the WHO-guideline.Conclusions: Findings indicate that those participants with more positive attitudes and higher perceived behavioral control had greater intentions to engage in physical activities.
