前十字韌帶損傷是一種相當普遍的運動傷害，大多數患者的受傷過程並非外在接觸性撞擊的影響，而是由於人體下肢在減速動作時，突然改變方向或是跳躍後落地動作不正常，造成前十字韌帶的負荷過大，導致非接觸性傷害的發生。前十字韌帶損傷後，在步態中可以發現有股四頭肌抑制(quadriceps avoidance)現象；在跑步方面，雖然沒有明顯股四頭肌抑制現象，但在著地期時，膝關節出現屈曲角度減少，與內側位移增加，顯示損傷後的膝關節呈現不穩定狀態。若接受前十字韌帶重建手術，在術後初期的步態中，依然會出現股四頭肌抑制現象，在術後4個月的步態已趨近於一般健康正常人的模式，然而，在脛骨旋轉動作卻仍然無法恢復至正常範圍，顯示經過前十字韌帶重建後，也無法完全恢復至受傷前的動作模式。未來研究方面，可以進一步探討穿戴護具或使用運動貼紮方法，能否有效地改善前十字韌帶損傷患者的生物力學表現。

Anterior cruciate ligament (ACL) injury is one of the most common sports injuries. The injury mechanism for most victims is the non-contact injury, resulting from the overload on the ACL due to the sudden change of moving direction in decelerating the lower extremity, or improper landing. Quadriceps avoidance is obvious in gait after ACL injury. The decreased knee flexion angle and the increased medial displacement in knee are found in the runners after ACL injury. Quadriceps avoidance in gait is still evident immediately after ACL reconstruction. However, gait pattern is reaching normal after the reconstruction of four-month, but tibial rotation is still obvious in gait. It is implied that it is difficult to regain the non-injured motion pattern even accepting ACL reconstruction. In the future studies, the effect of athletic taping or brace will be conducted to more understand the biomechanics of ACL injury so as to improve the athletic performance.