Effects of a Structured Resistance Training Program on Muscular Strength and Functional Performance in Children with Autism Spectrum Disorder: A 12-Week Intervention Study

Background/Objectives: Motor impairments, including reduced muscular strength and coordination, are commonly reported in children with autism spectrum disorder (ASD) and may negatively affect functional mobility and participation in daily activities. Despite increasing recognition of these challenges, structured resistance training programs for children with ASD remain limited. This study aimed to examine the effects of a 12-week resistance training program on muscular strength and functional performance in children aged 9–11 years with mild ASD. Methods: A selected-group repeated-measures design was employed. Twenty-eight children with specialist-confirmed mild ASD were allocated to an exercise (n = 14) or control group (n = 14) using a strength-matched allocation procedure. The intervention followed established exercise guidelines for youth. Assessments were conducted at baseline, week 6, and week 12 and included handgrip strength, vertical jump height, and 10-m walk time. Non-parametric Friedman tests assessed changes over time, followed by Durbin–Conover post hoc comparisons where appropriate. Effect sizes (r) were calculated. Results: No significant overall time effect was observed for handgrip strength, although a between-group difference favoring the exercise group was observed at week 6. Vertical jump height demonstrated a significant effect over time, with improvements observed in the exercise group from baseline to week 6 and a between-group difference at week 6. Walking time improved significantly across the study period, with improvements observed in both the exercise and control groups. Conclusions: These findings suggest that structured resistance training is a feasible intervention that may support improvements in physical function in children with mild ASD. Resistance training may therefore represent a useful component of exercise programs aimed at improving functional mobility and participation in children with developmental conditions.