Department of Physical Therapy, Allied Health Sciences Faculty, Burapha University, Chonburi 20131, Thailand.
Exercise and Nutrition Innovation and Sciences Research Unit, Burapha University, Chonburi 20131, Thailand.
Int J Environ Res Public Health. 2021 Apr 23;18(9):4510. doi: 10.3390/ijerph18094510.
The purposes of this study were to investigate the muscle-tendon unit stiffness response and to compare the stiffness with those of other indirect markers induced by two bouts of unaccustomed eccentric exercise. Eleven untrained men performed two bouts of 200 maximal eccentric contractions of the right quadriceps 4 weeks apart. Changes in stiffness, pain evoked by stretching and pressure, plasma creatine kinase (CK) activity, and muscle thickness were followed for 7 days after each bout. Stiffness and pain peaked immediately and 1 day after the first exercise bout, whereas CK and thickness were highest 4 and 7 days after the first exercise bout, respectively ( < 0.05 for all). Muscular pain, thickness, and stiffness responses were lower by 53.3%, 99%, and 11.6%, respectively, after the repeated bout compared to after the first bout ( < 0.05 for all), while CK activity response did not differ significantly between bouts. High responders for an increase in muscle-tendon unit stiffness showed a repeated-bout effect for stiffness, pain, and CK activity (by 29%, 65%, and 98%, < 0.05 for all), but the repeated-bout effect was not that clear in low responders. These findings suggest that a repeated eccentric exercise bout effect on stiffness in quadriceps is mostly not associated with muscle pain and CK activity, but there are large individual differences.
本研究旨在探究肌肉-肌腱单元的僵硬反应，并比较两回合不习惯的离心运动引起的僵硬与其他间接标志物的僵硬。11 名未经训练的男性在 4 周内分别进行了两回合 200 次最大离心收缩的右四头肌运动。在每次运动后，连续 7 天监测僵硬、拉伸和按压引起的疼痛、血浆肌酸激酶（CK）活性和肌肉厚度的变化。僵硬和疼痛在第一回合运动后立即和第 1 天达到峰值，而 CK 和厚度分别在第一回合运动后第 4 天和第 7 天达到峰值（所有指标均<0.05）。与第一回合相比，重复回合后肌肉疼痛、厚度和僵硬反应分别降低了 53.3%、99%和 11.6%（所有指标均<0.05），而 CK 活性反应在两回合之间无显著差异。肌肉-肌腱单元僵硬增加的高反应者在僵硬、疼痛和 CK 活性方面表现出重复回合效应（分别增加 29%、65%和 98%，所有指标均<0.05），但低反应者的重复回合效应不那么明显。这些发现表明，股四头肌的重复离心运动对僵硬的影响主要与肌肉疼痛和 CK 活性无关，但存在较大的个体差异。
