Ankle joint angle profile (A) and normalized soleus EMG (B). Data are the average of all subjects. (A) Ankle joint angle profiles are shown for unpowered (black) and powered condition (red). The error bars represent ± 1 standard deviation. Positive values indicate ankle plantar flexion. (B) Normalized soleus EMG of each time epoch was shown for the first unpowered (black), powered (red), and second unpowered (grey). Epoch 5, 6, and 8 (circled) were the points in time when we performed the H-reflex measurements.