棒球投手等速肌力與揮臂速度對投擲不同重量棒球之投球影響

Effects of isokinetic force and throwing-arm velocity on throwing performance during pitching different weighted baseballs

目的：探討等速肌力特性、揮臂速度、投球初速度、投球末速度之關係，並比較不同等速肌力特性投手與不同揮臂速度投手之差異，以及比較投擲不同重量棒球之差異。方法：以6位甲組成棒投手為研究對象，以Biodex system進行等速肌力測試，利用10臺Eagle紅外線攝影機（250Hz）之Motion Analysis System拍攝隨機投擲50、75、100、125、150、175、200、225、250、275、300公克等不同重量棒球之投球動作。結果：（1）等速肌力大小與等速肌力平衡達顯著負相關（p＜.05），揮臂速度與投球初速度具顯著相關（p＜.05）；（2）等速肌力平衡佳投手較等速肌力大投手有顯著較快的投球末速度（p＜.05）；（3）揮臂速度快慢投手之間有相近的等速肌力及投球球速表現；（4）揮臂速度、投球初速度、投球末速度等皆隨棒球重量的增加而有減慢的趨勢；（5）等速肌力大投手能產生最快揮臂速度和球速的棒球重量約100g－125g，揮臂軌跡變異性較大；但等速肌力平衡佳投手則約50g－75g，揮臂軌跡較具一致性。結論：投手除注重肌力提升外，宜注重肌力的平衡，建議肌力平衡佳投手可利用約50g－75g棒球，肌力大投手則可利用約100g－125g棒球進行投球訓練，以增進投球揮臂速度和球速，並可利用50g－75g棒球做為評量投手能力之重量。Purpose: to investigated correlation among isokinetic force, throwing arm velocity, pitching initial velocity, and pitching ending velocity. To comparison between pitchers of different isokinetic force characteristics and between pitchers of different throwing-arm velocity. To compare the throwing of various weighted baseballs. Method: Six elite pitchers measured isokinetic force by using Biodex System, and filmed by using Motion Analysis System at 250Hz when they threw randomly 50g, 75g, 100g, 125g, 150g, 175g, 200g, 225g, 250g, 275g, 300g baseballs. Results: (1) There was significant negative correlation between force quantity and force balance (p < .05, r = - .86). Throwing-arm velocity had significant correlation with pitching initial velocity (p < .05, r = . 77). (2) Pitchers with better force balance had faster pitching ending velocity than those with force quantity (t = -2.449, p = .04). (3) Pitchers with different throwing-arm velocity had similar isokinetic performance and pitching velocity (p > .05). (4) Throwing-arm velocity, pitching initial velocity, and pitching ending velocity were decreased with increasing baseball weight. (5) 100g-125g baseballs produced the fastest throwing-arm velocity and pitching velocity for pitchers with force quantity, and their arm trajectory had more deviation during throwing different weighted baseballs. In contrast, 50g-75g baseballs produced the fastest throwing-arm velocity and pitching velocity for pitchers with force balance, and their arm trajectory were lower deviation. Conclusion: Pitchers should pay more attention to both force balance and force increase. For this reason of increasing throwing-arm velocity and pitching velocity, 50g-75g and 100g-125g baseballs were more suitable weights for pitchers with force balance and with force quantity, respectively. 50g-75g were proper weights for evaluating pitchers ability.