1997 Volume 10 Issue 1 Pages 51-67
This study was purposed to know about baseball batters' reactions to hiting fast-speed (32m/sec) and slow-speed (21 m/sec) pitches by investigating how the hitting motion phases changed with time and how the weight was transfered in their hitting actions. University baseball players as experts and male university students who had a few-year-experiences to play baseball as novices, both hit the pitches on the two force-plates. Ground reaction forces in the hitting actions were measured by force-plates. And the hitting motions were video taped by a high-speed camera.
Weight transfer in the batters' hitting actions and change of motion phases with time suggested the following batters' responses to pitches.
1) Experts started stepping motion toward the pitcher earlier than novices did. And after landing of the stepped foot, momentary remaining of weight onto the stepped foot was followed by beginning of the bat-swing action. There were no differences between in hitting fast-speed pitches and in hitting slow-speed ones in experts' weight shifts.
2) Landing of the stepped foot and the motion phase of take-back top was shown at the same time by novices. Just after landing of stepped foot and the top of take-back, weighting onto the front foot (the stepped foot) and the bat-swing action were started. In their stepping motions, novices shifted their body weight from rear foot to front foot more remarkably in hitting slow-speed pitches than in hitting fast-speed pitches.
3) In hitting fast and slow speed pitches which were mixed randomly, experts started stepping motion and landed their stepped foot at the same timing at each speed. And when slow-speed pitches were delivered, they delayed to start putting weight onto the stepped foot and bat-swing actions for adjusting the timing of their motions to pitches' slow speed. By landing stepped foot early to prepare for fixing the stepped foot firmly on the ground, weight shift in hitting fast-speed pitches was the same as in hitting slow-speed ones. Novices timed their hitting motions to pitches' speed by adjusting the timing of landing stepped foot. Novices shifted their weight onto the stepped foot more than experts did. And they shifted their weight onto the stepped foot at the same time when the stepped foot were landed. Because of such kinds of motion styles, novices shifted their weight more onto the stepped foot before start of bat-swing in slow-speed pitches, and started bat-swing actions with incomplete weight shift onto the stepped foot in hitting fast-speed pitches.
