Costa Pablo B, Ruas Cassio V, Smith Cory M
Exercise Physiology Laboratory, Department of Kinesiology, California State University, Fullerton, CA, USA -
Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
J Sports Med Phys Fitness. 2018 Jul-Aug;58(7-8):957-965. doi: 10.23736/S0022-4707.17.07072-4. Epub 2017 Apr 13.
The present study examined the acute effects of hamstrings stretching and fatigue on knee extension and flexion peak torque (PT), hamstrings to quadriceps (H:Q) ratio, and postural stability.
Seventeen women (mean±SD age=21.8±2.1 years; body mass=63.0±10.5 kg; height=164.7±6.2 cm) and eighteen men (25.8±4.6 years; 83.6±13.2 kg; 175.3±6.0 cm) took part in three laboratory visits. The first visit was a familiarization session, and the subsequent two visits were randomly assigned as a control or stretching condition. For the testing visits, subjects performed a postural stability assessment, stretched (or sat quietly during the control condition), performed a 50-repetition unilateral isokinetic fatigue protocol, and repeated the postural stability assessment.
There were no significant differences between control and stretching conditions for initial quadriceps and hamstrings PT, initial H:Q ratio, quadriceps and hamstrings PT fatigue indexes, H:Q ratio Fatigue Index, rating of perceived exertion (RPE), or postural stability (P>0.05). When analyzing 5 intervals of 10 repetitions, significant declines in quadriceps PT were found in all intervals for both conditions (P<0.05). However, a decline in hamstrings PT was only found until the fourth interval (i.e., repetitions 31 to 40) for the stretching condition (P<0.05).
Stretching the hamstrings immediately prior to long-duration activities may eventually cause adverse effects in force-generating capacity of this muscle group to occur earlier when fatiguing tasks are involved. Nevertheless, no changes were found for the H:Q ratios after stretching when compared to no-stretching.
本研究探讨了腘绳肌拉伸和疲劳对膝关节伸展和屈曲峰值扭矩（PT）、腘绳肌与股四头肌（H:Q）比率以及姿势稳定性的急性影响。
17名女性（平均±标准差年龄=21.8±2.1岁；体重=63.0±10.5千克；身高=164.7±6.2厘米）和18名男性（25.8±4.6岁；83.6±13.2千克；175.3±6.0厘米）参与了三次实验室访问。第一次访问是熟悉环节，随后的两次访问被随机分配为对照或拉伸条件。在测试访问中，受试者进行姿势稳定性评估，进行拉伸（或在对照条件下安静坐着），执行50次重复的单侧等速疲劳方案，并重复姿势稳定性评估。
对照和拉伸条件在初始股四头肌和腘绳肌PT、初始H:Q比率、股四头肌和腘绳肌PT疲劳指数、H:Q比率疲劳指数、主观用力程度（RPE）或姿势稳定性方面无显著差异（P>0.05）。在分析10次重复的5个时间段时，两种条件下所有时间段的股四头肌PT均显著下降（P<0.05）。然而，仅在拉伸条件下的第四个时间段（即重复31至40次）发现腘绳肌PT下降（P<0.05）。
在长时间活动前立即拉伸腘绳肌，当涉及疲劳任务时，最终可能会使该肌肉群的力量产生能力更早地出现不利影响。然而，与不拉伸相比，拉伸后H:Q比率没有变化。
