Developmental aspects of pluriarticular movement control.

Precise pluriarticular movement control is required to perform straight and smooth out-and-back movements. Our goal was to determine whether children perform out-and-back movements as accurately as adults do in the presence and absence of visual feedback. To reach our goal, 36 children aged between 6 and 12 years, and 12 young adults, performed an out-and-back movement in a normal-vision condition and in a target-only condition. Reversal angle and overlapping error were taken to represent the ability of children to control pluriarticular movement. The results showed that adults exhibited sharper movement reversal than the three children groups did, but only for eccentric targets relative to their midline. This suggests that pluriarticular movement control improved across the course of development for eccentric regions of the workspace. Visual feedback did not result in sharper movement reversal even when relatively large errors were noted (eccentric targets in children). This underlines the relatively minor role of visual feedback for interjoint coordination when proprioception is intact. Finally, we observed that directional variability was smaller at the 100-ms mark for the back than for the out portion of the movement, suggesting that movement-planning processes appear less variable when based on dynamic rather than static afferent information.