Black Christopher D, Elder Christopher P, Gorgey Ashraf, Dudley Gary A
Department of Kinesiology, The University of Georgia, 330 River Road, Athens, GA 30602-6554, USA.
J Appl Physiol (1985). 2008 Mar;104(3):639-47. doi: 10.1152/japplphysiol.00322.2007. Epub 2007 Dec 13.
Animal models implicate multiple mechanical factors in the initiation of exercise-induced muscle injury. Muscle injury has been widely studied in humans, but few data exist regarding the underlying cause of muscle injury. This study sought to examine the role of torque per active muscle volume in muscle injury. Eight subjects performed 80 electrically stimulated [via electromyostimulation (EMS)] eccentric contractions of the right and left quadriceps femoris (QF) through an 80 degrees arc at 120 degrees /s. Specific torque was varied by applying 25-Hz EMS to one thigh and 100-Hz EMS to the contralateral thigh. Transverse relaxation time (T2) magnetic resonance images of the QF were collected before and 3 days after the eccentric exercise bouts. Injury was assessed via changes in isometric force and ratings of soreness over the course of 14 days after exercise and by determining changes in T2 and muscle volume 3 days after exercise. The 100-Hz EMS induced greater force loss (P < 0. 05), soreness (P < 0.05), change in muscle volume (P = 0.03), and volume of muscle demonstrating increased T2 (P = 0.005) than the 25-Hz EMS. In addition, injury was found to be similar across the QF in all but the most proximal regions of the QF. Our findings suggest that, in humans, high torque per active volume during lengthening muscle contractions is related to muscle injury.
动物模型表明多种机械因素与运动诱导的肌肉损伤的起始有关。肌肉损伤在人类中已得到广泛研究，但关于肌肉损伤潜在原因的数据却很少。本研究旨在探讨每单位活动肌肉体积的扭矩在肌肉损伤中的作用。八名受试者通过以120度/秒的速度在80度弧度内对左右股四头肌（QF）进行80次电刺激（通过肌电刺激（EMS））的离心收缩。通过对一侧大腿施加25赫兹的EMS，对另一侧大腿施加100赫兹的EMS来改变特定扭矩。在离心运动前和运动后3天收集QF的横向弛豫时间（T2）磁共振图像。通过运动后14天内等长力量的变化和酸痛评分，并通过确定运动后3天T2和肌肉体积的变化来评估损伤情况。与25赫兹的EMS相比，100赫兹的EMS导致更大的力量损失（P < 0.05）、酸痛（P < 0.05）、肌肉体积变化（P = 0.03）以及T2增加的肌肉体积（P = 0.005）。此外，除了QF最近端区域外，发现QF各部位的损伤情况相似。我们的研究结果表明，在人类中，肌肉拉长收缩过程中每单位活动体积的高扭矩与肌肉损伤有关。
