Electromyographic changes of leg muscles with heel lift: therapeutic implications.

The effects of heel lifts on activity in gastrocnemius and tibialis anterior muscles were analyzed by signal averaged EMG. The goal was to formulate a more rational approach to prescribing heel lifts for conditions such as tendoachilles bursitis and postoperative management of heel cord rupture. Thirteen men walked on a level floor and a treadmill with heel heights of zero, 1.9, 3.8, and 5.7 cm. Results showed that as heel height increased there was a significant decrease (p = 0.03) in gastrocnemius EMG activity and an increase (p = 0.04) in tibialis anterior EMG activity during level floor walking. Treadmill walking produced less remarkable decreases in gastrocnemius activity and increases in tibialis anterior activity, indicating differences between treadmill and level walking. We conclude that heel lifts of 1.9 to 5.7 cm for men decrease gastrocnemius muscle activity, thereby reducing tension in the Achilles tendon during normal level walking. Therefore, therapeutic use of heel lift is justified for men with tendoachilles bursitis, tenosynovitis of Achilles tendons, and postoperative management of ruptured Achilles tendons.