Hamadan University of Medical Sciences Journal of Education and Community Health 2820-896X 13 1 2026 03 31 Effect of Educational Multilevel Intervention Based on the Trans-Theoretical Model on Physical Activity Among Students 1 7 10.34172/jech.4856 EN Maryam Ahmadi https://orcid.org/0009-0001-9815-6382 Zabihullah Gharlipour https://orcid.org/0000-0003-4018-2438 Abolfazl Mohammadbeigi https://orcid.org/0000-0002-3142-6413 Mohammad Aligol https://orcid.org/0000-0001-8549-5791 Journal Article 10.34172/jech.4856 2025 08 20 2026 03 16 Introduction: Physical inactivity poses a major public health challenge worldwide, particularly among adolescents. This study aimed to assess the effect of an educational program grounded in the Trans-Theoretical Model (TMM) on physical activity among female high school students. Methods: This quasi-experimental study was conducted on 70 female eleventh-grade students in Qom, Iran. Participants were allocated to an intervention and a control group (n=35 per group). Physical activity was assessed using a multi-level approach based on the Trans-Theoretical Model. Data collection was conducted using the International Physical Activity Questionnaire (IPAQ) along with a researcher-developed questionnaire to measure TTM constructs. Data were analyzed via SPSS Version 27 using paired t-tests, independent t-tests, and chi-square tests. Results: Baseline measurements indicated that the intervention and control groups were comparable in terms of demographic characteristics and key baseline variables (P>0.05). Following the intervention, the intervention group showed significant improvements in physical activity and in the processes of change (P<0.05). In contrast, no significant differences were observed between groups in mean scores for stages of change, decisional balance, or self-efficacy (P>0.05). Conclusion: The multilevel educational intervention based on the TTM effectively enhanced students’ physical activity levels. These findings suggest that integrating behavior change models into school-based educational programs may be an effective strategy for promoting physical activity among adolescents.