DEVELOPMENT OF BILATERAL MOTOR CONTROL IN CHILDREN WITH DEVELOPMENTALCOORDINATION DISORDERS

This research examined behavioral (i.e. movement time) and neuromuscul ar (EMG) characteristics of unilateral and bilateral aiming movements of children with normal motor development and children with developmen tal coordination disorders (DCD). Two age groups of children were stud ied: 6 to 7, and 9 to 10 year olds. Bilateral aiming movements involve d moving the two hands to targets of either (1) the same amplitude - s ymmetrical bilateral movements, or (2) different amplitudes - asymmetr ical bilateral movements. Unilateral aiming movements involved moving one hand to either near of far targets associated with that hand. In g eneral, unilateral and bilateral movement times were slower in younger than older children, and in children with DCD than children with norm al motor development. Our neuromuscular data suggest that the faster m ovement times that typically accompany increasing age in children mag be the result of a change in the capacity to initiate antagonist muscl e contractions. The prolonged burst of agonist activity and delayed on set of antagonist activity observed in children with DCD may contribut e to their inability to produce fast, accurate unilateral movements. O n both symmetrical and asymmetrical bilateral aiming movements, childr en with DCD had more performance errors and greater temporal inconsist encies between neuromuscular (EMG) parameters and behavioral (movement time) parameters than children with normal motor development. These n ew neuromuscular data suggest that there are important differences in the way the motor control systems of children with and without DCD org anize bilateral aiming responses.