How different social contexts shape adolescents’ participation in extracurricular physical activities in western China: an analysis based on mixed-methods research

Introduction Extracurricular physical activities are important for adolescents’ physical and mental health. However, participation rates in western China remain generally low, and the relationships between environmental conditions and participation patterns require further investigation. Methods This study employed an exploratory sequential mixed-methods design. First, interviews were conducted with 14 physical education professionals. Relevant categories were identified through grounded theory analysis, and a hypothetical model was developed by integrating ecosystem theory and social cognitive theory. Subsequently, questionnaire data were collected from 933 middle school students. Structural equation modeling and the bootstrap method were used to examine direct associations and indirect effects. Results Qualitative analysis identified five core categories: the school sports environment (SSE), family sports support (FSS), policy and institutional supply (PIS), regional resource endowment (RRE), and exercise self-efficacy (ESE). Quantitative analysis showed that SSE ( β = 0.225, p < 0.001) and FSS ( β = 0.130, p = 0.004) were positively associated with physical education and physical activity (PEPA). The indirect effects mediated by ESE were 0.078 (95% confidence interval [CI]: 0.043–0.122) and 0.075 (95% CI: 0.043–0.116), respectively. The direct associations of PIS and RRE with PEPA were not statistically significance ( p > 0.05), whereas their indirect effects were 0.103 (95% CI: 0.069–0.149) and 0.064 (95% CI: 0.037–0.098), respectively. ESE was positively associated with participation behavior ( β = 0.375, p < 0.001). Conclusion Adolescents’ perceptions of SSE and FSS were directly association with PEPA and indirectly associated with it through ESE. PIS and RRE showed significant indirect associations with PEPA through ESE. These findings provide empirical evidence to inform efforts to strengthen school and family support for physical activity (PA), improve access to activity opportunities, and foster exercise self-efficacy among adolescents.