Physical fitness components as mediators between physical activity and executive function in adolescents: a cross-sectional study
Purpose This study examined whether physical fitness (PF) mediates the association between physical activity (PA) and executive function (EF) in Chinese adolescents. Methods A cross-sectional study was conducted from September to December 2023, involving 5,713 students aged 13–18 years recruited through stratified cluster random sampling. PA was assessed using questionnaires, PF through standardized field tests, and EF using computerized cognitive tasks. Partial correlation analyses and mediation models were performed. Results No significant sex differences were observed in inhibitory control or the 1-back task. Moderate-to-vigorous PA (MVPA) correlated positively with most PF indicators (p < 0.05). PF indicators were generally negatively correlated with EF measures (p < 0.05). The total effect of MVPA on 1-back performance was not significant (p = 0.109). However, in separate simple mediation models, MVPA showed significant specific indirect associations with working memory via core strength (indirect effect = −0.030), cardiorespiratory fitness (indirect effect = −0.021), and agility and coordination (indirect effect = −0.023) (95% CIs did not include 0; p < 0.05). In stratified analyses, indirect effects were significant in females, adolescents with normal weight, and those meeting screen-time guidelines, but not in males, senior high school students, adolescents with obesity, or those exceeding screen-time limits. Conclusion PF (specifically core strength, cardiorespiratory fitness, and agility and coordination) exerts an inconsistent (suppression) mediation effect in the relationship between MVPA and working memory in Chinese adolescents.