EMG patterns in two representative subjects for different hand-walking speeds.

<p>From <i>top</i> to <i>bottom</i>: anterior-posterior displacement of the left hand, EMG activity of 6 muscles of the left arm, a-p displacement of the left foot and EMG activity of 7 muscles of the left leg. Note non-linear changes in the EMG activity with speed: subject 1 (A) showed an increment in hamstring muscle activity while subject 2 (B) showed a decrease in hamstring and an increase in quadriceps activity. Note also the absence of noticeable activity in distal leg muscles.