Eston R G, Lemmey A B, McHugh P, Byrne C, Walsh S E
School of Sport, Health and Exercise Sciences, University of Wales, Gwynedd, UK.
Scand J Med Sci Sports. 2000 Aug;10(4):199-204. doi: 10.1034/j.1600-0838.2000.010004199.x.
The purpose of this study was to assess the effects of changes in stride length on the symptoms of exercise-induced muscle damage (EIMD) during a repeated bout of downhill running in a group of 18 men and women. Muscle tenderness, plasma creatine kinase activity (CK) and maximal voluntary isometric force were measured before and after two downhill runs, with each run separated by 5 weeks. The first downhill run was at the preferred stride frequency (PSF). Participants were then randomly allocated to one of three sex-balanced groups with equal numbers of men and women: overstride (-8% PSF), understride (+8% PSF) and normal stride frequency for the second downhill run. Stride length had no effect (P>0.05) on muscle tenderness, CK or isometric peak force. Increases in muscle tenderness (P<0.001) and CK were lower (P<0.05) following the second downhill run, although there was no difference in the pattern and extent of the strength decrement between the two runs. There were also no differences (P>0.05) in muscle tenderness, CK or the relative strength loss between the men and the women. Results suggest that the symptoms of EIMD are unaffected by gender and small alterations to the normal stride pattern during constant velocity downhill running. The observation that muscle tenderness and CK were reduced following a repeated bout of similar eccentric exercise is consistent with the phenomenon known as the 'repeated bout effect' of muscle damage.
本研究旨在评估在一组18名男性和女性进行的重复下坡跑过程中，步幅变化对运动诱发肌肉损伤（EIMD）症状的影响。在两次下坡跑之前和之后测量肌肉压痛、血浆肌酸激酶活性（CK）和最大随意等长肌力，每次跑步间隔5周。第一次下坡跑采用偏好步频（PSF）。然后，参与者被随机分配到三个性别均衡、男女数量相等的组之一：第二次下坡跑时步幅过大（-8%PSF）、步幅过小（+8%PSF）和正常步频。步幅对肌肉压痛、CK或等长峰值力没有影响（P>0.05）。第二次下坡跑后，肌肉压痛的增加（P<0.001）和CK较低（P<0.05），尽管两次跑步之间力量下降的模式和程度没有差异。男性和女性在肌肉压痛、CK或相对力量损失方面也没有差异（P>0.05）。结果表明，在匀速下坡跑过程中，EIMD的症状不受性别影响，且正常步幅模式的微小改变也不会产生影响。重复进行类似的离心运动后肌肉压痛和CK降低的观察结果与肌肉损伤的“重复运动效应”现象一致。
