Hand trajectory.

<p>(a) Typical subject. Origin is the mean hand position. Blue and red trajectories indicate the hand trajectory for 2 min in the WW and WS tasks. Yellow and green trajectories denote the mean hand trajectory in one cycle in the WW and WS tasks. (b) Amplitude of the mean hand trajectory in one cycle of oscillation of all subjects. The vertical axis denotes the amplitude of the hand trajectory, and the horizontal axis denotes the amplitude direction (horizontal and vertical). Blue and red bars indicate the hand trajectory amplitude in the WW and WS tasks. Asterisk denotes a significant difference. Specific values of the amplitude of the hand trajectory are listed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125464#pone.0125464.s004" target="_blank">S4 Table</a>.