Effects of a game-based exergame intervention on motor competence and balance in children with autism spectrum disorder: a multiple-baseline single-case experimental study

Children with autism spectrum disorder (ASD) frequently exhibit impairments in manual dexterity, gross motor coordination, and balance. Game-based exergames provide structured, feedback-rich practice that may enhance motor competence. Evidence based on rigorously controlled single-case experimental designs remains limited. This study examined the effects of a volleyball-based exergame intervention on motor competence and balance in children with ASD. A hybrid single-case experimental design was used, combining staggered multiple baselines across four contexts (catching, tossing, spike-jump, and integrated play) with A–B–A′–B′ reversals over 16-week period from September 2025 to December 2025 in two elementary-school children with ASD (a fourth-grade boy, Full Scale IQ = 93, with low muscular endurance; and a third-grade girl, Full Scale IQ = 121, with localized hypotonia). Weekly task-based probes aligned with Movement ABC-3 domains assessed manual dexterity, aiming and catching, and balance. Pre/post standardized testing was administered. Analyses included visual analysis, randomization tests, and non-overlap indices (Tau-U, NAP). Both participants demonstrated consistent improvements in manual dexterity, with moderate-to-large non-overlap effect sizes and clear level and trend changes during intervention phases. One participant showed pronounced gains in balance, while the second displayed ceiling effects. Improvements in aiming and catching were limited and non-significant on randomization test results. Replication across contexts and participants supported experimental control. These preliminary findings suggest that the volleyball-based exergame intervention has the potential to enhance manual dexterity and balance for children with ASD, with limited effects on object-interaction skills. Given the exploratory nature of this N=2 study, findings suggest that structured, feedback-driven exergame environments may serve as feasible and engaging potential adjuncts to school-based motor intervention programs, though larger-scale studies are needed to confirm causal claims. Not applicable.