不同層級棒球投手投擲快速直球手部肌肉活化之分析

Abstract

不同層級棒球選手投擲動作技術優劣可以球體與人體兩層面加以評估，其中以球速與轉速為判定的重要指標，但僅以最後結果表現推估可能不夠完整與客觀，更重要的是釐清人體手部控制的協調性在過程中如何作用。本研究隨機招募12名大專公開組男子棒球選手與12名一般大專生，釐清投擲快速直球時，球速、轉速、上肢尺側伸腕肌、橈側屈腕肌、手背第一、第二、第三與第四背側骨間肌肌肉活化差異，並瞭解兩組各肌群肌肉活化與球速、轉速的相關性。結果發現，優秀組選手的球速與轉速皆顯著高於一般組，但兩組組間上肢與手背肌電訊號皆無顯著差異；兩組的第一背側骨間肌電訊號皆顯著大於第三背側骨間肌。轉速方面，優秀組選手的第二與第四背側骨間肌顯著大於第三背側骨間肌，一般組皆無顯著差異，且兩組的肌肉活化皆與球速無顯著相關；但優秀組伸腕肌肌電訊號與轉速有顯著正相關。本研究結論為，優秀組球速雖然快於一般組選手但兩組選手的手部四條背側骨間與伸腕肌、屈腕肌的肌電訊號沒有顯著差異，影響棒球選手的投球的球速可能與其他肌群有關。背側骨間肌的活化主要作用可能為協助控球，因此與球速的提升顯著相關。此外，優秀組投擲轉速之所以高於一般組，主因可能為優秀組透過伸腕肌的活化在離手瞬間進行制動，並將動量傳至手指給予球體動力；反觀一般組則未產生此現象。

The throwing techniques of different levels of baseball players can be evaluated in two elements:"ball" and "human body". The releasing and rotation velocity of the ball are the two important index of throwing technique. The coordination of human limbs control might be more important that it will influent the final performance. The purpose of the study was to explore the coordination of hand muscle activation while throwing the fast balls. The study randomly recruited 12 male college baseball players in Group A and 12 general college students. Using smart baseball, wireless surface EMG, andhigh-speed camera to clarify the different muscle activation of upper limb extensor carpi ulnaris, flexor carpi radialis, and first to fourth dorsal interossei muscles while throwing ball balls. And understanding the correlation between the muscle activation and the ball speed and rotation speed of two groups. The results showed that the ball speed and rotation speed of the group A were higher than those of the general group, but there was no significant difference in muscle activation between two groups. We found there were no significant difference between muscle activation and ball speed in two groups. There was a significant positive correlation between extensor carpi ulnaris EMG signal and ball rotation velocity in group A. In conclusion, the main reason why the ball speed of the excellent group faster than those of the general group was not clear by forearm EMG signals. The dorsal muscle groups of hands might play the role to stable while the ball releasing. We found the EMG signal of the extensor carpi ulnaris might be the reason to brake the wrist movement to increase the momentum of the fingers in the releasing phase of the group A.