EMG of slow and fast ankle extensors of cat during posture, locomotion, and jumping

Publisher Website
Google Scholar
Abstract
Myoelectrical signals for a slow (soleus) and fast (lateral gastrocnemius) ankle extensor of 6 adult female cats were monitored during quadrupedal and bipedal standing, treadmill locomotion at speeds ranging from 0.5-2.5 m/s and vertical jumps from heights of 30-91 cm. While the soleus, which participated in all activities, showed little change in activity level between movements of varying dynamics, the lateral gastrocnemius was recruited primarily during movements requiring rapid, forceful ankle extensions. Thus, from a quiet stand to a moderately high jump (91 cm), the rectified-averaged electromyogram (A-EMG) for soleus increased less than 1.5 times, while the A-EMG for lateral gastrocnemius increased 4-fold relative to soleus. The EMG data supported the notion that segregation of fast and slow fibers into different muscles represent functional specializations matched to the demands of motor control.

This publication has 2 references indexed in Scilit: