緒論：前十字韌帶傷害是常見的膝關節運動傷害之一，過去研究發現女性運動員發生的比率高於男性二到四倍，經常發生在單腳支撐期的急停減速動作，此階段的腿後肌群扮演著穩定膝關節工作。一般在運動前常透過動態伸展來進行暖身，而過去研究也發現動態伸展是可以增加肌肉的活化以及力量，因此利用動態伸展來增加腿後肌群的活化或力量是有效預防前十字韌帶傷害的方式之一。本研究主要目的為透過腿後肌群的動態伸展，觀察女性運動員在側向切入動作的膝關節生物力學特徵。方法：招募10名健康大專女性運動員（身高166.1±4.5公分、體重59.1±8.2公斤、年齡22.7±2.4歲），實驗參與者必須執行側向切入動作及腿後肌群動態伸展。實驗儀器使用8台Vicon紅外線攝影機（250 Hz）、1塊Kistler測力板（1000 Hz）與5顆Delsys無線肌電（2000 Hz）同步收集側向切入動作時的生物力學參數。使用重複量數單因子變異數分析比較伸展前及伸展後的差異。結果：在動態伸展後著地階段的膝外翻力矩峰值時半腱肌、股二頭肌活化和肌肉共同收縮（H/Q值）顯著增加，而動態伸展後膝內翻力矩峰值時，垂直地面反作用力與膝內翻力矩峰值顯著下降，但膝關節角度和伸展前相比則未達顯著差異。結論：透過動態伸展可增加腿後肌群的活化，藉此提升膝關節著地時的緩衝能力，降低地面反作用力使膝關節的力矩減少，進而促進前十字韌帶傷害的預防。

Introduction: Anterior cruciate ligament (ACL) injury was one of the common sport-related knee injuries. The previous study found that female athletes were 2 to 4 times higher prevalence of ACL injury than male athletes. ACL injury usually occurred at sudden stop and deceleration phase during single leg stance where hamstrings acts to stabilized the knee joint. The common warm up was dynamic stretching and the previous study found that it could enhance muscle activation and strength. Therefore, using dynamic stretching to increase hamstrings activation or strength might be one of the possible method to prevent ACL injury. The purpose of this study was to investigate the influence of hamstrings dynamic stretching on knee joint biomechanical parameters of female athletes during side-cutting tasks. Methods: There were 10 healthy female collegiate athletes (22.7 ± 2.4 year, 59.1 ± 8.2 kg, 166.1 ± 4.5 cm) participated in this study. Participants had to perform side-cutting and hamstrings dynamic stretching. Biomechanical data were collected synchronously by 8 VICON cameras (250 Hz), 1 Kistler force plate (1000 Hz) and 5 Delsys wireless EMG sensors (2000 Hz) during side-cutting tasks. One-way ANOVA with repeated measures was used to compare each biomechanical parameter before and after hamstrings dynamic stretching. Results: Participants showed significantly greater semitendinosus and biceps femoris activation and muscle co-contraction ratio (H / Q ratio) after hamstrings dynamic stretching during peak knee valgus moment occurred. Vertical ground reaction force and peak knee varus moment decreased significantly after hamstrings dynamic stretching during peak knee varus moment occurred, but knee angles were no significant difference after hamstrings dynamic stretching. Conclusion: Dynamic stretching could increase the activation of the hamstrings, and improved shock absorption of the knee joint during landing phase which could decrease ground reaction force to reduce the knee moment. Therefore, it might promote the prevention of anterior cruciate ligament injury.