研究背景：反覆高速度衝刺跑經常造成腿後腱肌肌群具高損傷率，特別是股二頭肌肌群。損傷危險因子包括；柔軟度不足、疲勞、肌力不足等。因此，運動項目如能針對股二頭肌進行訓練，可能能預防腿後腱肌損傷。但是，「伸展運動」與「肌力運動」預防腿後腱肌損傷研究結果仍未定論。研究發現，特殊肌力運動，如「仰躺腿部捲曲 (supine leg curl，SLC) 及髖關節伸展運動 (hip extension，HE) 肌力運動型態」，主要誘發股二頭肌產生較大動作電位活性。此外，「主動開放動力鍊式伸展運動」，似乎會降低肌肉功能表現，但「主動閉鎖式伸展運動」以及肌肉血液阻斷 (ischemia preconditioning，IPC) 可能能提升下肢肌肉表現及延遲疲勞發生。然而，短期及長期肌力運動 (SLC 與HE)、主動式伸展，並搭配IPC預處理，以及恢復期進行不同伸展運動與IPC處理，對反覆衝刺跑後肌肉功能及肌肉損傷影響為何，尚無研究提出論證。研究目的：第一年計畫：探討(1)不同訓練組數之特殊肌力及主動式伸展運動，對腿後腱肌肌肉結構、肌力及肌肉損傷指標之影響、(2)不同組數之特殊肌力與主動式伸展運動後對反覆衝刺跑損傷影響。延續第一年，第二年計畫：探討(1)連續1、3及5天之肌力及主動式伸展訓練之影響、(2)不同伸展運動及搭配IPC處理對反覆衝刺跑後恢復期影響。延續第二年，第三年計畫：探討(1)是否長期肌力運動、主動式伸展運動及伸展搭配IPC處理能降低反覆衝刺跑損傷。研究方法：第一年將招募60名一般健康大專男性(柔軟度及離心肌力不足)，隨機分成5組 (每組各12名)。第一組：SLC組、第二組：HE組、第三組：主動式直膝抬腿伸展(active straight leg rise stretching，ASLS)、第四組：(straight leg deadlift, single leg windmill，SLW)、第五組：控制組(無任何處理)。該研究共進行兩個階段，第一階段，各組須進行反覆衝刺跑運動。第二階段，各組以平衡次序方式進行3種不同訓練組數(1、3及5組，每組12下)之進行肌力或主動式伸展運動(每種間隔1週休息時間)，並再訓練後各進行反覆衝刺跑運動。依變項測量時間點，分別為，反覆衝刺跑前與後、肌力及伸 展運動前與後及恢復期。第二年將招募60名受試者(柔軟度及離心肌力不足)，隨機分成五組，第一組：SLC組、第二組：HE組、第三組：ASLS、第四組：SLW、第五組：控制組(無任何處理)。該研究共進行兩個階段，第一階段，先進行一回合反覆衝刺跑後，休息3天，接著再以平衡次序方式進行3種訓練天數方式(1、3及5天，每天1組12下)，在每種訓練天數方式後皆須各進行反覆衝刺跑運動，第二階段，僅控制組在反覆衝刺跑後以平衡次序方式進行4種伸展或IPC恢復處理。依變項觀察時間點依序如，肌力及伸展運動前後、衝刺跑運動前後及恢復期。第三年將招募60名受試者(柔軟度及離心肌力不足)，以隨機方式分至五組。第一組：SLC組、第二組：ASLS組、第三組：ASLS+IPC組、第四組：SLW組、第5組控制組(完全不進行任何處理)，每組12名]，訓練組每週訓練3天，共8週。當8週訓練後須連續進行2天反覆衝刺跑運動，並觀察肌肉功能、肌肉氧化作用、血液動力學及損傷生化指標。依變項測量時間點：肌力及伸展前、8週後立即、後5天恢復期。本研究價值，將驗證特殊肌力運動、主動式伸展及搭配IPC熱身預處理與恢復處理，在反覆衝刺跑運動後對腿後腱肌肌肉功能影響，可能能提供預防腿後腱肌損傷及損傷後復健之運動處方。
Background: Hamstring strain injuries are the most prevalent injury type in high repeated speed running (especially for the biceps femoris muscle). The potential risk factors included lack of flexibility, fatigue, and insufficient hamstring strength. Exercises that mostly affect biceps femoris muscle may be important in respect to prevention of hamstring muscle strain injury. But the effect of stretching and strength injury prevention training is still inconsistent. The study indicated that the supine leg curl (SLC) and hip extension (HE) specifically targeted the BF at very high levels of normalised EMG. Furthermore, the active open-chained stretching precondition may be impaired muscle performance. But the active open-chained stretching and ischemia preconditioning (IPC) is more effective in increasing muscle performance and delayed the development of fatigue. However, before the repeated sprints exercise, it remains unclear the short and long-term effects of strength exercise (SLC and HE), active stretching, and combined with IPC treatments on muscle performance and muscle injury. Moreover, it remains unclear the effect of active stretching and combined with IPC on recovery from high repeated sprint exercise. Objective: The purpose of the first year study to investigate (1) varying amounts of strength and active stretching exercise treatment repeated sprint exercise on muscle architecture, muscle strength, muscle injury markers. (2) the effects of different strength and active stretching exercise treatment on repeated sprint exercise. In the second year (1) to investigate the effects of 1, 3 or 5-day strength, active stretching exercise and (2) the different stretching exercise or combined with IPC on recovery from high repeated sprint exercise. In the third year (1) if a long-term strength, active stretching exercise and stretching combined with IPC training would attenuate muscle injury by high repeated sprint exercise. Methods: For the first year, we will be recruited 60 subjects with limited hamstring flexibility and with weaker or stronger eccentric hamstring strength. The subjects will randomly assigned to 1 of 5 groups (n=12 per group). (1) SLC group、(2) HE group、(3) ASLS group、(4) SLW group、(5) Control group (no any treatment). First period, all participants performed repeated sprint exercise. Second period, each group will perform 3 different treatment (1, 3, 5 sets，12 repetitions per set) in a counterbalanced order followed performed repeated sprint exercise. The outcomes measured were determined at immediately before and after repeated sprint exercise, stretching and strength exercise. For the second year, 60 subjects with limited hamstring flexibility and weaker eccentric hamstring strength will be recruited into our study. Subjects will randomly assign to 1 of 5 groups. (1) SLC group、(2) HE group、(3) ASLS group、(4) SLW group、(5) Control group (no any treatment). First period, each group will perform 3 different treatments (1, 3, 5 days，12 repetitions per day) in a counterbalanced order and followed performed repeated sprint exercise. Second period, first the Control group performed the repeated sprint exercise, there were 4 recovery treatments in a counterbalanced order for the Control group. The outcomes measured were determined at immediately before and after repeated sprint exercise, stretching and strength exercise. For the third year, 60 subjects with limited hamstring flexibility and weaker eccentric hamstring strength will be recruited into our study. Subjects were randomly assigned to 1 of 5 groups (4 training groups and 1 control group). The 4 training groups participated 3 days per week for a 8-week period. The hamstring muscle architecture, muscle strength, flexibility, muscle oxygenation and biochemical markers were determined at immediately before, after 8-week and 5 days after repeated sprint exercise. The contribution of this study, the aim was to determine the specific strength, active stretching exercise and combined with the IPC warm up preconditioning and recovery treatment on hamstring muscle performance during repeated sprint exercise. And this is an important knowledge in injury prevention and rehabilitation programmes.