Fig. 1.

Experimental setup for wrist movements (A) and reaching movements (B). A. Subjects rotated their wrist in combinations of flexion-extension (FE) and radial-ulnar deviation (RUD) to point to targets on a screen. Each movement required 15° of wrist rotation. B: subjects also made planar shoulder-elbow (reaching) movements toward targets. Each movement required 14 cm of displacement of the hand. Both wrist and reaching movements included fast, medium, and slow movements (durations of 300, 550, and 900 ms, respectively).