FIG. 6.

Evolution of muscle activation patterns. (A) Prevalence of muscle activation patterns at the start, middle, and end of clonus. (B) EMG ratios for individual muscles at clonus end plotted against muscle activation patterns. Muscles include ipsilateral tibialis anterior (TA), hamstrings (HM), vastus lateralis (VL), contralateral soleus (CL-SL), and tibialis anterior (CL-TA). Two active muscles included ipsilateral triceps surae and tibialis anterior (TS+TA). Activation of a third muscle (hamstrings, + HM), a fourth muscle (vastus lateralis, + VL), and five or six muscles (one or two contralateral muscles, + CL-SL±TA) corresponded to three, four, five, or six muscles, respectively.