不同材質棒球木棒之特性分析

摘要緒論:不同木質材質棒體會導致擊球表現有所不同，本研究以振動參數與恢復係數為指標探討山毛櫸木、白梣木與楓木材質之棒體特性差異，提供棒球用具相關研發廠商、教練與選手更完整的棒體特性依據。方法:分別將球棒固定於工作台上以棒球發球機進行撞擊，透過加速規(Norason, DTS 3D ACC, 2000 Hz)與一台高速攝影機 (Casio EX-F1, Japan, 300Hz)收取振動與恢復係數參數，再以單盲實驗設計，分別讓受試者依序持握各材質棒體，進行打擊測試完後立即填寫棒體特性主觀知覺量表。將收取來之相關參數利用SPSS 23.0，以獨立樣本單因子變異數分析 (One-way ANOVA)，分別考驗三種不同棒球棒材質各軸向振動幅度、合加速度、恢復係數與主觀知覺差異，若達顯著再以 LSD法進行事後比較，統計水準訂為α = .05。結果:在球棒物理測試中山毛櫸木恢復係數最高且有最低的甜區內外、垂直、合加速度振幅與最低的握把處垂直、合加速度振幅，而白梣木則有最低的甜區水平振幅，此外楓木有最低的內外握把處振幅。在選手知覺測試方面選手多數認為山毛櫸木硬度最高，並與物理測試結果一致，但不同的是楓木材質最能抑制振動，且有較快的反彈球速，其整體感受也最佳。結論:物理碰撞測試後，山毛櫸木具有較佳的棒體特性，但從選手偏好使用楓木材質，且相較水平與垂直振幅量更在意內外軸向振幅量，說明物理碰撞測試最佳的棒體材質，不見得為選手偏好使用的棒體，建議棒球用具相關研發廠商，在進行棒體材質之物理碰撞測試時，需更著重於內外軸向振動的測試，此外需透過單盲實驗設計，瞭解選手之主觀知覺感受，以取得更完整之棒體特性依據，藉此製造研發出適合選手之棒球相關用具，以利提升選手運動表現。

關鍵字

振幅；恢復係數；山毛櫸木；白梣木；楓木

並列摘要

Abstract Introduction: Batting performance shall be related to the material characteristics of wood baseball bat. Thus, the vibration parameters and coefficient of restitution of wood baseball bats made by beech, white ash, and hard (sugar) maple are the important indexes of the study. These analyses can be useful for baseball equipment manufacturers, coaches, and baseball players. Methods: The wood baseball bat is fixed on the platform and hit by the baseball casted from the baseball pitcher machine, defined as the physical hitting test of the wood baseball bat. An acceleration gauge (Norason, DTS 3D ACC, 2000 Hz) and a high speed camera (Casio EX-F1, Japan, 300Hz) are used to collect the vibration parameters as well as the coefficient of restitution of wood baseball bats. The single-blind striking test is conducted by subjects to hold three different material rods in sequence. Thereafter, the attenders are asked to fill the subjective perception scale questionnaire based on their feelings of three different material rods. One-way ANOVA of the IBM SPSS 23.0 based on the collected information is used to analyze the vibration amplitude, acceleration, as well as the coefficients of restitution of these three wood bats along many directions. After the analysis reaching the significant level, the posteriori test unplanned comparisons are conducted based on the least significant difference (LSD) and level of significance α = .05. Results: Among these three wood materials, the coefficient of restitution of beech wood baseball bat is highest one. Its vibrational amplitude and acceleration measured at the inside/outside of the sweet zone and along the vertical direction are also the lowest. Its vibrational amplitude and acceleration measured at the holding spot of the bat are also the lowest. The horizontal vibration amplitude measured in the sweet zone is lowest for the white ash wood baseball bat. The horizontal vibration amplitude measured at the inside and outside of holding spot of the hard maple wood baseball bat is lowest. According to the questionnaire, most of the attenders think that the hardness of beech wood bat is the most one, and it confirms with the result of the physical hitting test. The hard maple wood baseball bat with good ability to suppress the vibration can result in that the bouncing speed of baseball hit by it is fast. Therefore, its total subjective perception is the best for attenders. Conclusions: The results of physical hitting test are best for the white ash wood baseball bat. As mentioned above, however, most of the baseball player attenders prefer the hard maple wood baseball bat, because they care vibration amplitude along the inside and outside axes more than that along the vertical and horizontal directions. In other words, the better result of physical hitting test may not be the best choice for the baseball players. Therefore, manufacturers of baseball equipment conducting the physical hitting test shall pay attention to the vibration amplitude along the inside and outside axes. The single-blind striking test can also be used to realize the subjective perception of the baseball players, so the more complete characteristics of wood baseball bats can be obtained to improve the performance of the baseball bat and the players.