Behavioral and neurocognitive effects of judo training on working memory capacity in children with ADHD: A randomized controlled trial

•Judo training increased visuospatial working memory capacity in children with ADHD.•Increased contralateral delay activity at high memory load was found following judo training.•This change indexed more effective maintenance processes and/or increased attentional control.•Benefits for working memory capacity occurred despite no changes in motor skills. Children with Attention Deficit Hyperactivity Disorder (ADHD) face deficits in working memory capacity that often persist into adulthood. In healthy peers, exercise targeting motor skill acquisition benefits visuospatial working memory, but its potential to reduce ADHD-related deficits remains unclear. We investigated the effect of a judo training program targeting motor skills on behavioral and neurocognitive indices of working memory capacity in children with ADHD. Children with ADHD aged 8 to 12 years (N = 57) were randomly allocated to a judo training group and a wait-list control group. The training program encompassed 120 min of judo per week over three months. Before and after the intervention period, participants completed a bilateral Change Detection task with low and high memory load conditions and the Movement Assessment Battery for Children-2 (MABC-2). The contralateral delay activity (CDA) elicited by the cognitive task was recorded using electroencephalography. Compared to the control group, the judo training group showed a higher K-score on the Change Detection task and an increased negativity of the CDA on the high load condition following the intervention, when pretest scores (and confounders) were accounted for. In contrast, no group differences were found for MABC-2 score. In children with ADHD, judo training may complement the pharmacological treatment by increasing the effectiveness of working memory maintenance processes. On a behavioral level, this improvement is accompanied with an increased capacity to store visuospatial information.