The impact of fitness social media use on exercise behavior: the chained mediating role of intrinsic motivation and exercise intention.

Objective: This study aimed to investigate the psychological mechanisms by which fitness social media use influences individuals' exercise behavior, focusing on the chained mediating roles of intrinsic motivation and exercise intention. Methods: A cross-sectional online survey was conducted in April 2025 using snowball sampling, targeting social media users who regularly engage in physical activity. A total of 425 valid responses were analyzed. Constructs including fitness social media use, intrinsic motivation, exercise intention, and exercise behavior were assessed using validated Likert-scale instruments. Structural equation modeling and bootstrap analysis (5,000 resamples) were applied to test the hypothesized chained mediation model. Results: Fitness social media use was found to significantly predict intrinsic motivation ( Conclusion: These findings demonstrate that fitness social media use not only exerts a direct effect on exercise behavior but also influences it indirectly through a sequential psychological process involving emotional activation and cognitive planning. The study provides novel empirical evidence supporting the integration of Self-Determination Theory and the Theory of Planned Behavior, thereby offering a deeper understanding of how health behaviors form within digital contexts. In practical terms, this research highlights the significant role of social media-based digital platforms in enhancing intrinsic motivation and exercise intention. Future health-promotion interventions should therefore focus more explicitly on leveraging fitness social media to strengthen individuals' intrinsic motivation and foster clear behavioral intentions, ultimately facilitating sustained engagement in physical activity and elevating overall population levels of physical activity.