不同蹲踞式起跑之下肢肌電訊號與等速肌力特徵分析

Abstract

目的：探討不同蹲踞式起跑於起跑出發階段之運動學參數與下肢肌群肌電訊號間之差異及與下肢等速肌力之相關。方法：以短距離田徑男選手7名為研究對象，利用高速攝影、肌電系統以及等速肌力測定儀，擷取選手三種不同蹲踞式起跑所產生之運動生物力學參數。繼以重複量數單因子變異數分析，並進行F考驗，本實驗將顯著水準訂為α=.05，參數如達顯著水準，則進行事後比較。事後比較則採用（LSD）法進行。結果：運動學部分，膝關節角度在三種不同蹲踞式起跑下前腳關節角度為85~95度，後腳關節角度為125~139度，長式起跑在起跑出發後第一步離地瞬間重心高度變高，第一步步幅大於短式及中式起跑方式，在第二步著地瞬間左膝、踝關節角度明顯增加。肌電訊號部份，受試者在三種不同蹲踞式起跑時慣用腳（後腳）肌電訊號類似且一致性，隨著起跑板間的距離增長，股外側肌在起跑預備期扮演重要的角色。等速肌力部分，透過不同角速度下之等速肌力訓練，可提升三種不同蹲踞式起跑的重心水平速度表現。結論：三種不同蹲踞式起跑都很適合選手使用，教練需透過平時訓練找出真正適合選手的起跑方式，才能幫助選手創造佳績。Purpose: The study aimed at comparing kinematic parameters, lower –extremity EMG signals, and lower –extremity isokinetic strength among different couching starts. Method: The subjects of this study were seven short-distance track and field players. The players’ kinematic parameters were collected through high-speed cameras, EMG systems, and isokinetic measurement systems. One-way ANOVAs of repeated measures (α=.05) and LSD for Posteriori comparison were conducted. Results: Regarding kinematic parameters among couching starts, the angles of the front leg knee joints were between 85° and 95°, while the angles of the rear leg knee joints were between 125° and 139°. In the elongated start, the subjects’ center of gravity height increased at the moment their first step left the ground after starting running, their first step length was larger than in the bunch start and medium start, and the angles of their left knee and ankle joints increased obviously at the moment when their second step touched the ground. The EMG signals of the subjects’ common used foot (rear foot) during the three different couching starts were similar and consistently increased with the distance between the distance between front and back blocks. Vastus Lateralis muscles play an important role during the preparation for sprint start. In terms of isokinetic strength, the findings suggested that isokinetic training of different angular speed would increase horizontal velocity of center of gravity. Conclusion: All of the three sprints starts types were appropriate for players. Through trainings, coaches should investigate the most appropriate sprint start type for their players in order to help them create their best performances.