To flexibly regulate their behavior, childrens ability to inhibit prepotent responses arises from cognitive and motor mechanisms that have an intertwined developmental trajectory. Subtle differences in planning and control can contribute to impulsive behaviors, which are common in Attention Deficit and Hyperactivity Disorder (ADHD) and difficult to be assessed and trained. We adapted a Go/No-Go task and employed a portable, low-cost kinematic sensor to explore the different strategies used by children with ADHD or typical development to provide a prepotent response (dominant condition) or inhibit the prepotent and select an alternative one (non-dominant condition). Although no group difference emerged on accuracy levels, the kinematic analysis of correct responses revealed that, unlike neurotypical children, those with ADHD did not show increased motor planning in non-dominant compared to dominant trials. Despite motor control could have compensated and led to good accuracy in our simple task, this strategy might make inhibition harder in more naturalistic situations that involve complex actions. Combining cognitive and kinematic measures is a potential innovative method for assessment and intervention of subtle differences in executive processes such as inhibition, going deeper than is possible based on behavioral outcomes alone. Significance StatementThis study proposes an innovative method that integrates kinematic measurement with neuropsychological evaluation, thus providing information on the planning and control mechanisms underlying behavioral outcomes. It is applicable to the study not only of inhibition but more generally of executive functions, which are the basis of the ability of children and adults to achieve goal-directed actions. The use of a wearable motion sensor ensures good applicability in research, clinical evaluation, and intervention.