大學棒球打者下肢力量及力量不對稱性與揮棒速度的關聯

目的：本研究旨在檢視大專棒球打者之大腿中部等長拉力測驗 (isometric mid-thighpull test, IMTP ) 的肌力表現以及其雙側差異與揮棒速度的關聯。方法：大學棒球野手20 名，進行 IMTP 與揮棒速度測驗後，依照其絕對力量對稱指數值分為低 (LSI)、中 (MSI)、高 (HSI) 力量對稱組，比較三組在揮棒速度與力量表現的差別，以及分析全體及分組在變項之間的關係。結果：全體參與者的力量峰值與揮棒速度有顯著的關係 (p < .05)。各組間在揮棒速度、力量的峰值和發力率皆無顯著的差異。HIS 的力量表現與球速有正相關，而 LSI 則相反。各組的發力率、力量峰值間有不同的正向關聯：HIS 的力量峰值與 250 毫秒的發力率有關，MSI 的各分段的發力率幾乎都有所關聯，LSI 的 150 毫秒發力率與力量峰值有顯著的關係。結論：下肢等長拉力的峰值越大，揮棒速度越快。不同程度的力量不對稱性，會有不同的力量發展型態以及與揮棒速度的關係。  Purpose: The presented study aimed to examine the relationship between isometric mid-thigh-pull test (IMTP) and swing speed in college baseball hitters. Methods: Twenty college fielders participated and implemented the tests of IMTP and swing speed. They then were divided into low (LSI), medium (MSI), and high (HSI) force symmetry groups according to their absolute force symmetry index values. The differences in swing speed and IMTP performances were compared between three groups, and the patterns of relationship in variables for overall and groups were analyzed. Results: There was a significant relationship between peak force and swing speed (p < .05). No significant difference was found between groups in swing speed and IMTP performances. HSI and LSI have different relationships between force and ball speed in which the HSI has positive relationship while reverse for LSI. The relation between force development rate and peak force value were varied in groups in which the HSI had related peak force value and force development rate of 250ms, the MSI had relations in most force development rates, and the LSI had significant relation between force development rate of 150ms and peak force value. Conclusion: The greater the peak isometric midthigh pull force of the lower body, the faster the swing. Different degrees of force asymmetry will have different force development patterns and relationships with swing speed.