Pitching performance and muscle strength
The ball velocity was measured using a radar gun (Speedster V, Bushnell, USA) positioned 3 m behind the home plate. Video images were recorded using an HD 60 fps camera (GZ-E780, JVCKENWOOD, Japan) positioned 3 m behind the home plate. These video images were used to determine the pitching accuracy (i.e., the percentage of pitches crossing the strike zone during flight). Accuracy was determined by the same investigator. The handgrip strength of the dominant hand was measured using a handgrip dynamometer (T.K.K.5401, Takei, Japan) after the warm-up, REST, and each inning.