Background: Children with Developmental Coordination Disorder (DCD) have motor difficulties which impact their everyday activities. Difficulties with Executive Function (EF) are commonly reported with relationships between EF and motor skills poorly understood. A key component of EF is Inhibition, important for classroom learning and less explored in children with DCD. Study One aimed to investigate the EF skills of children with and without DCD focusing on Inhibition, and Study Two aimed to examine relationships between Inhibition and motor skills. Method: Participants were 25 children with DCD aged six-ten years, and 25 age and gender matched typically developing (TD) children. They completed experimental measures of Inhibition, standardised tests of motor and EF skills, and parents and teachers completed standardised EF questionnaires. Results: Study One. Children with DCD had significantly poorer performance on some experimental and standardised measures of Inhibition and on parent and teacher reports of overall EF skills. Inhibition difficulties were reported by parents but not teachers. Results emphasize the potential for task and environmental demands to influence EF and Inhibition performance. Study Two. Significant relationships between at least one Inhibition measure and all areas of motor skills were found across groups. However, relationships differed across motor domains and Inhibition measures. Many within group correlations were also significant, although there was variation across the DCD and TD groups. This suggests that relationships between EF and motor skills are different for those with and without DCD. Conclusion: Children with DCD have difficulties with Inhibition across a range of measures and some aspects of performance are associated with their level of motor skills. The motor and Inhibition difficulties observed in children with DCD appear to be interdependent. Assessment of children with DCD should include an examination of Inhibition skills. Interventions should consider development of Inhibition as well as motor skills.
