Department of Health Science and Technology, Faculty of Medicine, Center for Neuroplasticity and Pain (CNAP), SMI, Aalborg University, Aalborg, Denmark.
Department of Physiotherapy, University College North Denmark, Aalborg, Denmark.
Scand J Med Sci Sports. 2018 Jan;28(1):29-39. doi: 10.1111/sms.12905. Epub 2017 May 29.
Delayed onset muscle soreness (DOMS) occurs within 1-2 days after eccentric exercise, but the mechanism mediating hypersensitivity is unclear. This study hypothesized that eccentric exercise reduces the blood flow response following muscle contractions and cuff occlusion, which may result in accumulated algesic substances being a part of the sensitization in DOMS. Twelve healthy subjects (five women) performed dorsiflexion exercise (five sets of 10 repeated eccentric contractions) in one leg, while the contralateral leg was the control. The maximal voluntary contraction (MVC) of the tibialis anterior muscle was recorded. Blood flow was assessed by ultrasound Doppler on the anterior tibialis artery (ATA) and within the anterior tibialis muscle tissue before and immediately after 1-second MVC, 5-seconds MVC, and 5-minutes thigh cuff occlusion. Pressure pain thresholds (PPTs) were recorded on the tibialis anterior muscle. All measures were done bilaterally at day 0 (pre-exercise), day 2, and day 6 (post-exercise). Subjects scored the muscle soreness on a Likert scale for 6 days. Eccentric exercise increased Likert scores at day 1 and day 2 compared with day 0 (P<.001). Compared with pre-exercise (day 0), reduced PPT (25%, P<.002), MVC (22%, P<.002), ATA diameter (8%, P<.002), ATA post-contraction/occlusion blood flow (16%, P<.04), and intramuscular peak blood flow (~23%, P<.03) were found in the DOMS leg on day 2 but not in the control leg. These results showed that eccentric contractions decreased vessel diameter, impaired the blood flow response, and promoted hyperalgesia. Thus, the results suggest that the blood flow reduction may be involved in the increased pain response after eccentric exercise.
延迟性肌肉酸痛（DOMS）在离心运动后 1-2 天内发生，但介导超敏反应的机制尚不清楚。本研究假设离心运动减少了肌肉收缩和袖带闭塞后的血流反应，这可能导致累积的致痛物质成为 DOMS 中致敏作用的一部分。12 名健康受试者（5 名女性）在一条腿上进行背屈运动（五组 10 次重复的离心收缩），而对侧腿为对照。记录胫骨前肌的最大自主收缩（MVC）。使用超声多普勒在胫骨前动脉（ATA）和胫骨前肌组织内评估血流，在 1 秒 MVC、5 秒 MVC 和 5 分钟大腿袖带闭塞前后进行。记录胫骨前肌的压力疼痛阈值（PPT）。所有测量均在运动前 0 天（运动前）、运动后 2 天和 6 天（运动后）双侧进行。受试者在 6 天内用李克特量表对肌肉酸痛进行评分。与运动前（0 天）相比，离心运动后第 1 天和第 2 天的 Likert 评分增加（P<.001）。与运动前（0 天）相比，DOMS 腿在第 2 天的 PPT（25%，P<.002）、MVC（22%，P<.002）、ATA 直径（8%，P<.002）、ATA 收缩后/闭塞后血流（16%，P<.04）和肌肉内峰值血流（~23%，P<.03）降低，但在对照腿中没有降低。这些结果表明，离心收缩会减小血管直径，损害血流反应，并引起痛觉过敏。因此，结果表明，血流减少可能与离心运动后疼痛反应增加有关。
