Motor differences in jumping among children with and without autism spectrum disorder

Background: Motor impairments in autism are prevalent yet understudied, especially complex skills like jumping. This study compared jump performance and lower-limb kinematics between children with autism spectrum disorder (ASD) and typically developing (TD) peers. Methods: Ten children with ASD (aged 3–6 years) and ten age-matched TD children performed two-legged jumps in a biomechanics laboratory. Jump distance, height, and sagittal-plane hip, knee, and ankle kinematics during preparatory and loading phases were measured. Group differences were analyzed using one-way multivariate analysis of covariance, with age included as a covariate. Findings: One-way ANCOVA, controlling for age, revealed a significant decrease in jump distance in the ASD group compared to the TD group (mean difference = −0.18 m, p = 0.043, ηp2[jls-end-space/]=0.219). Jump height did not differ between groups (p = 0.463). During the preparatory phase, the ASD group demonstrated significantly lower hip flexion (mean difference = −10.30°, p = 0.019, ηp2[jls-end-space/]=0.285). Peak knee flexion (p = 0.138) and peak ankle dorsiflexion (p = 0.349) were not significantly different. At take-off, ankle plantarflexion was also comparable between groups (p = 0.485). In the loading phase, the ASD group showed significantly reduced peak hip flexion (mean difference = −14.03°, p = 0.050, ηp2[jls-end-space/]=0.208) and peak knee flexion (mean difference = −10.70°, p = 0.034, ηp2[jls-end-space/]=0.238). Peak ankle dorsiflexion during landing was not significantly different (p = 0.374). Interpretation: Children with ASD demonstrate altered jumping mechanics, characterized by shorter jumps and restricted lower-limb flexion, which may reflect coordination challenges distinct from general developmental delay. These findings underscore the importance of assessing and addressing motor skills in ASD to support physical activity and participation.