Fig. 7

Response of unperturbed leg: Altered Timing. Averaged muscle activity and joint kinematics of the unperturbed (right) leg for a representative subject. Plotted from top to bottom is the normalized TA EMG, normalized SOL EMG, hip flexion (+) - extension (−), knee flexion (−) - extension (+) and ankle dorsi (+) - plantar (−) flexion. Mean (darker lines) and standard deviations (lightly shaded areas) values for gait cycles pertaining each timing of the perturbation are shown along with an indication of the timing of each perturbation. Statistically significant changes are indicated by colored bars (corresponding to each perturbation timing, aligned vertically from earliest to latest in the gait cycle) that are placed beneath a black asterisk. Heel-strike and toe-off of the right leg are indicated by HS and TO, respectively. The duration of the data plotted is approximately 3.3 s