Figure 4. Photograph series representing one gait cycle during treadmill walking.

The series of frames corresponds to one stride from heel strike of the left leg (highlighted in white in the first and last frame) to the next heel strike of the same leg. The filter output using the transfer functions for each measured muscle of the left leg corresponding to the heel strike of the ipsilateral leg, found using the adaptive filtering, are shown alongside the images of one stride duration. (A)  =  , (B)  =  , (C)  =  and (D)  =  , HS  =  Heel strike.