Figure 2. Example of an averaged data record for one subject with the perturbed trials and control trials superimposed.

A full step cycle for the left leg is shown. The perturbed (thick line) and control (thin line) records are shown superimposed. The time base is shifted so that zero corresponds with the stretch onset. A, ankle angular position with an offset such that 0 deg corresponds to the position at the time of stretch onset. B, soleus (SOL) EMG. C, tibialis anterior (TA) EMG.