Department of Rehabilitation, Faculty of Health Sciences, Nihon Fukushi University, Handa, Japan.
Department of Physiology, University of Kentucky, Lexington, USA.
J Sports Sci Med. 2019 Feb 11;18(1):13-20. eCollection 2019 Mar.
Dynamic stretching (DS) is often performed during warm-up to help avoid hamstring muscle injuries, increase joint flexibility, and optimize performance. We examined the effects of DS of the hamstring muscles on passive knee extension range of motion (ROM), passive torque (PT) at the onset of pain (as a measure of stretch tolerance), and passive stiffness of the muscle-tendon unit over an extended period after stretching. Twenty-four healthy subjects participated, with 12 each in the experimental and control groups. Stretching was performed, and measurements were recorded using an isokinetic dynamometer pre-intervention, and at 0, 15, 30, 45, 60, 75, and 90 min post-intervention. DS consisted of ten 30-s sets of 15 repetitions of extension and relaxation of the hamstrings. ROM increased significantly (range, 7%-10%) immediately after DS, and the increase was sustained over 90 min. PT at the onset of pain also increased immediately by 10% but returned to baseline by 30 min. Passive stiffness decreased significantly (range, 7.9%-16.7%) immediately after DS, and the decrease was sustained over 90 min. Post-DS values were normalized to pre-DS values for the respective outcomes in both groups. ROM was significantly higher (range, 7.4%-10%) and passive stiffness was significantly lower (range, 5.4%-14.9%) in the experimental group relative to the control group at all time points. Normalized PT values at the onset of pain were significantly higher in the experimental group at 0-15 min than in the controls, but the differences were smaller at 30-45 min and not significant thereafter. We conclude that DS increases ROM and decreases passive stiffness in a sustained manner, and increases PT at the onset of pain for a shorter period. Overall, our results indicate that when performed prior to exercise, DS is beneficial for the hamstring muscles in terms of increasing flexibility and reducing stiffness.
动态拉伸（DS）常用于热身运动中，以帮助预防腿筋肌肉受伤、增加关节灵活性和优化表现。我们研究了对腿筋肌肉进行 DS 对被动膝关节伸展幅度（ROM）、疼痛起始时的被动扭矩（PT）（作为拉伸耐受度的测量）以及伸展后长时间内肌肉-肌腱单位的被动僵硬度的影响。24 名健康受试者参与了研究，其中实验组和对照组各 12 名。在干预前、干预后 0、15、30、45、60、75 和 90 分钟，使用等速测力计进行拉伸并记录测量值。DS 由十组 30 秒的 15 次伸展和放松腿筋组成。ROM 在 DS 后立即显著增加（幅度为 7%-10%），并持续 90 分钟。疼痛起始时的 PT 也立即增加了 10%，但在 30 分钟时恢复到基线。DS 后被动僵硬度立即显著降低（幅度为 7.9%-16.7%），并持续 90 分钟。两组的各个结果在 DS 后的值均归一化为 DS 前的值。ROM 在实验组中始终显著更高（幅度为 7.4%-10%），而在实验组中被动僵硬度始终显著更低（幅度为 5.4%-14.9%）。在实验组中，疼痛起始时的归一化 PT 值在 0-15 分钟时显著高于对照组，但在 30-45 分钟时差异较小，此后无统计学意义。我们的结论是，DS 以持续的方式增加 ROM 和降低被动僵硬度，并在较短的时间内增加疼痛起始时的 PT。总体而言，我们的结果表明，在运动前进行 DS 对腿筋肌肉在增加柔韧性和降低僵硬度方面是有益的。
