Do Your Peers Matter? Peer Effects in Adolescent Physical Exercise.

Background: Peers' physical exercise behaviors may influence adolescents' participation in physical exercise; however, few studies have systematically explored peer effects in physical exercise among adolescents.

Methods: Data from the China Education Panel Survey were used to examine peer effects in adolescent physical exercise within classroom units. A total of 14,998 seventh- and ninth-grade students from 405 classes across 106 schools nationwide participated in this study.

Results: Significant and positive peer effects in physical exercise within classroom units were observed, with classmates' average extracurricular exercise time positively influencing individual extracurricular exercise time. This result remained robust after sequentially controlling for individual and family characteristics, contextual effects, and correlated effects, as well as after applying the instrumental variable method and conducting robustness checks. Further moderation analysis revealed that age negatively moderated the relationship between classmates' and individual extracurricular physical exercise time, whereas other demographic and family characteristic variables showed no significant moderating effects.

Conclusion: The design of adolescent physical education policies and the implementation of exercise promotion programs should adequately take peer effects into consideration and expand the social multiplier effect of exercise, thereby effectively enhancing youth engagement in physical exercise.