The purpose of this study was to clarify the effects of the muscular strength exerted during times of non-fatigue and fatigue and shouting, and to clarify the characteristics of muscular strength during times of fatigue. Grip strength was measured using the digital grip strength dynamometer for thirty healthy males. The following results were obtained.

1. The grip strength was significantly higher during shouting for both times of non-fatigue and fatigue than when there was no shouting.

2. Shouting had a significantly higher effect during times of fatigue than when there was no fatigue.

3. The value of grip strength significantly declined up to the forty-fifth trial, but the grip strength significantly increased just before the end at the fiftieth trial indicating an end spurt.

The results of the trial shows that grip strength increased when shouting for both times of non-fatigue and fatigue. The increases in muscular strength effect was greater when shouting during times of fatigue. And, an end spurt was recognized near the end of the trial resulting in an increase in muscular strength.