Fig. 1

Representative data from stroke survivors’ muscle activity patterns demonstrating the sensitivity of k-means cluster analysis to identify “on/off” periods. Each row presents EMG signals for a) soleus, b) tibialis anterior, and c) medial gastrocnemius from stroke survivor’ single gait cycle. Left panels present original EMG data and the right panels present the same representative data after it were high pass filtered (20 Hz) with a zero lag fourth-order Butterworth filter, demeaned, rectified, and smoothed with a zero lag fourth-order low-pass (25 Hz) Butterworth filter. The red solid lines represent k-means clusters