Effects of femoral nerve stimulation on voluntary soleus EMG activity in two stroke participants and one control participant. Tracings of averaged rectified EMG activities of ten trials are presented for the paretic sides of stroke participants with severely (A) or slightly (B) impaired coordination and for the right leg of a control participant (C). Arrows indicate the zero central delay, which is the expected time of arrival of the fastest FN Ia volley at the segmental level of the soleus motoneuron (Mn) pool. The latency scale is presented from 20 ms to 80 ms after FN stimulation (lower scale) and from 0 to 36 ms after the zero central delay (upper scale). Horizontal lines represent the mean amplitude of the unconditioned EMG activity (baseline EMG level). Facilitation was assessed within the time window from 0 to 6 ms after the zero central delay. Asterisks represent significant modulations of soleus within three time windows of analysis from 0 to 6 ms, 12 to 24 ms and 24 to 36 ms after the zero central delay (* p ≤0.05; ** p ≤0.01; *** p ≤0.001).