Abstract
INTRODUCTION: Although physical activity benefits youth development, little is known about how it is related to prosocial behavior over time, especially among structurally disadvantaged groups such as rural left-behind children in China. This longitudinal study examined the bidirectional relationship between physical activity and prosocial behavior and the mediating role of psychological resilience. METHODS: A total of 612 children (Grades 5-6; approximately 10-12 years old; 50.5% male) from three schools in Ji'an City, Jiangxi Province, completed measures of physical activity, psychological resilience, and prosocial behavior at three time points over 6 months. RESULTS: Crosslagged mediation structural equation modeling revealed reciprocal pathways: Time 1 physical activity was related to Time 3 prosocial behavior, and vice versa. In both directions, psychological resilience at Time 2 significantly mediated these associations (indirect effects = 0.07 and 0.04, respectively; ps < 0.001). These findings underscore psychological resilience as a key developmental mechanism linking physical and social functioning. DISCUSSION: The results highlight the potential for integrated school-based interventions that promote physical activity to enhance psychological resilience and social functioning in vulnerable youth populations, particularly rural left-behind children.