Moderate-to-Vigorous Physical Activity and Psychiatric Symptoms in Children with ADHD: Exploring the Mediating Role of Gross Motor Performance

ABSTRACT Objective To examine whether gross motor performance mediated the association between physical activity and psychiatric symptoms in children with Attention-Deficit/Hyperactivity Disorder (ADHD), and whether these effects would be moderated by individual characteristics. Methods Seventy-six children with ADHD aged 6-12 years were included in this cross-sectional study. Moderate-to-vigorous physical activity (MVPA) was assessed by a wrist-worn ActiGraph GT9X accelerometer for seven consecutive days. Parents self-reported their children’s psychiatric symptoms, including both internalizing and externalizing symptoms, via the Chinese version of the parent informant Child Behavior Checklist. Gross motor performance, including object control and balance, was measured by the Movement Assessment Battery for Children Second Edition. Mediation and moderation effects were performed by Hayes PROCESS macro for R. Results MVPA was positively correlated with object control and negatively associated with withdrawn and anxious/depressed symptoms. Both object control and balance showed negative correlations with anxious/depressed symptoms. Object control was also negatively correlated with withdrawn symptoms and aggressive behavior. Through the bootstrapping method, the indirect effect of object control (indirect effect = -0.081, 95%CI = -0.171 to -0.007) was found between MVPA and anxious/depressed symptoms. Additionally, this association was more pronounced in younger children with ADHD compared to their older counterparts (index of moderated mediation = 0.055, 95% CI: 0.005 to 0.150). Conclusions Object control mediated the association between MVPA and anxious/depressed symptoms in children with ADHD. Future physical activity interventions are suggested to emphasize the early development of gross motor skills through moderate-to-vigorous intensity activities to help reduce internalizing symptoms in this population.