Spatial and temporal constraints on performance in children with movement co-ordination problems.

Eight 10-year-old children manifesting movement co-ordination problems (MCP), as assessed by the Movement Assessment Battery for Children (MABC), and a matched control group of eight children of a similar age without such problems, were required to carry out a laboratory ball-catching task. The task was constrained in such a way as to allow separate kinematic analyses of reaching (Experiment 1) and grasping (Experiment 2) subactions. Significant differences between the groups, in favour of the control group, were found with respect to both spatial and temporal performance in intercepting the moving ball. The MCP children were shown to initiate reaching movements later and to initiate grasping movement of the fingers earlier in time than the controls. MCP children also made more spatial errors. These findings are discussed in the context of the distinction made in the neuropsychological literature between proximal and distal motor control systems and the visual perceptual system.