握持球棒位置對打擊運動學之影響

Abstract

緒論：當前的棒球打者會採用不同握棒位置來執行特定打擊策略。然而目前仍缺乏研究調查這些握棒方式對於全身性的運動學、擊球速度、擊球角度以及擊球負荷之影響。方法：18 位臺灣大專棒球聯賽公開一級組球員參與本研究。所有受試者皆為右打，並以標準握棒、握短棒與握長棒進行5公尺拋打實驗。每個握棒方式各打擊 10 次，共收集 540 筆有效數據。使用 Vicon三維動作分析系統搭配Visual 3D，捕捉與分析人體運動學數據、使用Rapsodo Hitting 2.0 用於判斷擊球速度與擊球角度。結果：在腳觸地階段，手臂外展角度隨著握棒長度而顯著減少 (短棒>標準>長棒)，而骨盆角度則是隨著握棒長度而減少 (短棒<標準<長棒)；擊球瞬間時，握短棒的後手手肘屈曲角度是最小的，而標準握棒又顯著小於握長棒。握短棒的骨盆旋轉角速度峰值顯著小於標準握棒和握長棒，但握短棒的右手肘伸展角速度峰值以及棒頭線性速度在擊球瞬間顯著大於其他兩種握棒方式。握短棒擊球速度顯著小於標準握棒和握長棒。擊球角度方面，握長棒的擊球角度顯著大於其他兩種握棒方式。計算站立、重心轉移和腳觸地發生的時間點，站立和重心轉移沒有發現顯著差異，但握短棒的腳觸地時間點顯著早於標準握棒和握長棒。結論：握短棒可提高後手肘伸展速度上，產生較高的棒頭速度，但因為球棒的有效質量 (effective mass) 的影響，擊球速度方面最慢，而握長棒需要相對較高的骨盆旋轉速度帶動，並且有較高的擊球角度，較容易形成高飛球。Introduction: Current baseball batters employ various grip positions to execute specific hitting strategies. However, there is a lack of research investigating the effects of these grip methods on overall biomechanics, bat speed, launch angle, and hitting load. Methods: This study involved 18 players from Taiwan’s collegiate baseball league, all right-handed hitters. They participated in a 5-meter hitting experiment using three different grip methods: “All fingers on the bat shaft” (AO), “Chock-up on the bat” (CU), and “One finger off the bat shaft” (OF). Each grip method involved 10 hits, resulting in 540 valid data points. We utilized the Vicon 3D motion analysis system in conjunction with Visual 3D to capture and analyze kinematic data. Rapsodo Hitting 2.0 was used to determine exit ball speed and launch angle. Results: During the foot contact timing, the arm abduction angle significantly decreased with grip length (CU>AO>OF), while the pelvic angle decreased with grip length (CU<AO<OF). CU had the smallest trailing elbow flexion angle at the ball contact timing, with AO also significantly smaller than OF. CU exhibited significantly lower peak pelvic rotational angular velocity than AO and OF, but CU had significantly higher peak right elbow extension angular velocity and linear bat head velocity at ball contact. CU had significantly lower exit ball speed compared to AO and OF. Concerning launch angle, OF hada significantly greater launch angle than the other two grip methods. The timing of stance, load, and foot contact was calculated, with no significant differences in stance and load timing, but CU's foot contact occurred significantly earlier than AO and OF. Conclusion: Choking up on the bat (CU) enhances the angular velocity of the trailing elbow, resulting in higher bat head velocity, but due to the influence of “effective mass,” it exhibits the slowest hitting speed. On the other hand, One finger off the bat shaft (OF) requires a relatively higher pelvic rotation speed to drive and has a higher launch angle, making it more likely to produce fly balls.