Early effects of denervation on isometric and isotonic contractile properties of rat skeletal muscles.

The contractile properties of the fast-twitch m. extensor digitorum longus (EDL) and the slow-twitch m. soleus were examined after 5 days of denervation. An increase in twitch time to peak, twitch half relaxation time and twitch/tetanus ratio was observed. The EDL also showed a moderate decrease in maximal isotonic shortening velocity, which is taken as an indication that the contractile proteins are affected. A fatigue test showed that the EDL became less fatigable and the soleus less fatigue resistant after denervation.