The relationship between physical activity and social network site addiction among adolescents: the chain mediating role of anxiety and ego-depletion

Background and objectives Physical activity is associated with social network site addiction in adolescents, yet the mechanisms remain unclear. This study examines whether anxiety and ego-depletion mediate this relationship. Methods A survey was conducted among 1,174 Chinese adolescents (614 boys, 560 girls; mean age = 12.59, SD = 1.13). Physical activity was assessed with a single item on moderate-to-vigorous exercise in the past 7 days. Social network site addiction, anxiety, and ego-depletion were measured using validated self-report questionnaires. Descriptive statistics, correlation analyses, and a chained mediation model were employed. Results Physical activity was negatively correlated with social network site addiction (r = -0.165, p < 0.001), anxiety (r = -0.121, p < 0.001), and ego-depletion (r = -0.119, p < 0.001). Anxiety was positively correlated with ego-depletion (r = 0.574, p < 0.001) and social network site addiction (r = 0.388, p < 0.001). Ego-depletion was positively associated with social network site addiction (r = 0.456, p < 0.001). Anxiety and ego-depletion sequentially mediated the relationship between physical activity and social network site addiction. Conclusion This study clarifies the psychological mechanisms linking physical activity and social network site addiction in adolescents, identifying anxiety and ego-depletion as key mediators. The findings emphasize the need to target these factors for more effective interventions.