MUSCULAR CONTROL OF THE ANKLE IN RUNNING

The purpose of this study was to describe and compare the muscle firin g patterns of the muscles controlling the ankle during running. Fine-w ire electrodes monitored the activity of the gastrocnemius, soleus, pe roneus brevis, tibialis posterior, and tibialis anterior muscles durin g 3 paces of running. High-speed film was used to synchronize the elec tromyographic data with the phases of running. The subjects were 15 re creational and competitive runners who were injury-free. There were 3 significant findings. First, the firing patterns of all of the posteri or muscles demonstrated peak activity during midstance phase. Thus, th ese muscles were contracting in an eccentric fashion to control ankle dorsiflexion as the center of gravity passed over the ankle. Second, t he tibialis anterior muscle fired above the fatigue threshold for 85% of the time. This may account for the high number of fatigue-related i njuries to the tibialis anterior muscle seen in runners. Third, there was a significant increase of activity in the peroneus brevis muscle a s the pace increased. This indicates the importance of training this m uscle when pace is increased. Using this information, a sport-specific effective and efficient exercise program for runners can be developed .