Tracking error and speed increase from initial trial to last trial. A: Non-disabled subjects in the Guidance group significantly reduced more the tracking error than subjects who trained without guidance. B: Non-disabled subjects in the Guidance group significantly increased the speed after training, and there was a non-significant tendency of a greater speed increase in the guidance group (p = 0.1413). Error bars in all plots show +/- 1 SD. *p < 0.05.