Background
An importance issue for pediatric health is to understand how to enhance the level of physical activity of children and adolescents. The purpose of the present study was to investigate the effects of a physical education-based intervention on promoting physical activity and well-being of primary school’s students.  
Materials and Methods: The present causal-comparative field study was conducted on 300 primary school girls (mean age: 10.72±0.73 years) of Urmia city, West Azerbaijan province, Iran, in 2019. The participants were randomly allocated into two groups including intervention (n=150), and control groups (n=150). Participants of intervention group were exposed to a six months’ intervention and 2 sessions per week based on social cognitive and social-ecological theories within the physical education classes, while those in control group followed their regular school tasks. Physical activity behavior and physical and psychological well-being were measured as dependent variables. Data were analyzed using SPSS software (version 16.0).
Results:
Age of participants in intervention and control group was not significantly different. Results of pretest showed that the participants of both group had similar physical activity behavior and well-being at baseline. However, the participants in the intervention group reported higher physical activity level (F = 17.11, P < 0.001) and physical (F = 30.76, P < 0.001), and psychological (F = 36.03, P < 0.001) well-being in comparison to those in control group in the posttest.
Conclusion
These results highlight the importance of developing physical education-based interventions for improving physical activity level and well-being of primary school-aged children.