Motor skills influence social function through health-related fitness in children with autism: a cross-sectional study

Objective: To examine whether health-related physical fitness mediates the association between fundamental motor skills (FMS) and social functioning in school-age children with autism spectrum disorder (ASD). Methods: A total of 117 school-age children with ASD were recruited from special education schools. FMS were assessed using the Test of Gross Motor Development-3 (TGMD-3). Social functioning was evaluated using the Social Responsiveness Scale-2 (SRS-2), with higher scores indicating greater social impairment. Health-related physical fitness was assessed via body mass index, flexibility (sit-and-reach), muscular strength (handgrip), muscular power (standing long jump), balance (one-leg stance), and vital capacity. Pearson correlation analyses and structural equation modeling with bias-corrected bootstrapping (5,000 resamples) were conducted to test mediation effects. Results: < 0.001). Several health-related physical fitness components, particularly handgrip strength and flexibility, were significantly associated with both FMS and social functioning. Structural equation modeling demonstrated a full mediation effect, whereby health-related physical fitness significantly transmitted the association between FMS and social functioning (indirect effect B = -2.111, 95% CI -3.576, -1.189), while the direct effect was not significant (B = -0.095, 95% CI -1.193, 1.274). Model fit indices indicated an excellent fit. Conclusion: Health-related physical fitness, especially muscular strength and flexibility, appears to be a key mechanism linking motor skill proficiency to social functioning in children with ASD. Interventions that integrate strength and mobility training with motor-skill practice may enhance social outcomes in this population.