Figure 6.

Interlimb coordination during transspinal stimulation. The electromyographic (EMG) activity of the right soleus (SOL) or tibialis anterior (TA) muscles is plotted against that of the left homologous muscle (SOL or TA) for steps without (top row: black) and during single pulse transspinal stimulation delivered randomly at each bin of the step cycle (green) in able-bodied subjects and individuals with spinal cord injury (SCI). An L-shape supports reciprocal activity between the homologous SOL or TA muscles and thus interlimb coordination. No changes in the L-shape were observed in able-bodied subjects (A). In contrast, single pulse transspinal stimulation distorted the L-shape, and thus interlimb coordination in SCI subjects (B). The step cycle was divided into 16 equal bins. Bin 1 corresponds to heel contact. Bins 8, 9, and 16 correspond approximately to stance-to-swing transition, swing phase initiation, and swing-to-stance transition, respectively.