We investigated the electromyographic (EMG) properties and circulatory response during, before and after the enhanced physiological tremor (EPT) events. Six healthy male subjects performed the prolonged static contractions in triceps surae muscles at an ankle joint angle of 120° at 20% of maximal voluntary contraction (MVC) as a fatigue test. The physiological tremor enhanced by prolonged static muscle contractions, which tremor cycle was 8-10Hz, disappeared after lasting for 10-20 sec. All subjects could continue to sustain the same workload after the EPT events. We observed 1) significant (p<0.05) decreases in the EMG activity of gastrocnemius muscles to the initial level of the fatigue test, and 2) significant (p<0.05) increases in leg blood flow and the vascular conductance after the EPT events compared to before EPT events appeared. Repetitive muscle contractions induced by the EPT events are seemed to contribute as a muscle pump function during the prolonged static muscle contractions. This suggests the functional significance of the EPT for the temporary reduction of muscle fatigue during endurance work.

DESCENTE SPORTS SCIENCE Vol.24/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE