Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.
Research Fellow of Japan Society for the Promotion of Science, Chiyoda, Tokyo, Japan.
Scand J Med Sci Sports. 2018 Jan;28(1):95-106. doi: 10.1111/sms.12880. Epub 2017 Apr 6.
This study examined localization of muscle damage within the quadriceps femoris induced by different types of eccentric exercises by using transverse relaxation time (T )-weighted magnetic resonance imaging (MRI). Thirty-three young males performed either of the following three exercises: single-joint eccentric contraction of the knee extensors (KE), eccentric squat (S), or downhill walking (DW) (n=11/exercise). KE and S consisted of 5-set×10-lowering of 90% one-repetition maximum load. DW was performed for 60 minutes with -10% slope, 6 km/h velocity, and 20% body mass load carried. At pre- and 24-, 48-, and 72-hours post-exercise, T -MRI was scanned and T values for the rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL), and vastus medialis (VM) at proximal, middle, and distal sites were calculated. Additionally, soreness felt when static pressure was applied to these sites and maximal isometric knee extension torque were measured. Maximal torque significantly (P<.05) decreased (7%-15%) at 24-48 hours after all exercises. T significantly increased (3%-9%) at 24-72 hours after all exercises, with heterogeneities within the muscles found in each exercise. Effect size and peak change of T , as well as soreness, overall indicated that the proximal RF after KE and middle VM after S and DW were most affected by these exercises. The VL did not show any significant T increase after all exercises. These results suggest that muscle damage specifically localizes at the proximal RF by KE and at the middle VM by S and DW, while the VL is least damaged regardless of the exercises.
本研究采用横向弛豫时间（T ）加权磁共振成像（MRI）技术，研究了不同类型的离心运动对股四头肌肌损伤的定位。33 名年轻男性分别进行了以下三种运动中的一种：单关节膝关节伸展肌离心收缩（KE）、离心蹲（S）或下坡行走（DW）（每组 11 人）。KE 和 S 包括 5 组×10 次，以 90%的最大重复次数降低。DW 以 -10%的坡度、6 公里/小时的速度和 20%的身体质量负荷进行 60 分钟。在运动前、运动后 24、48 和 72 小时，对 T-MRI 进行扫描，并计算股直肌（RF）、股中间肌（VI）、股外侧肌（VL）和股内侧肌（VM）在近、中、远部位的 T 值。此外，还测量了在这些部位施加静态压力时的酸痛感和最大等长膝关节伸展扭矩。所有运动后 24-48 小时，最大扭矩均显著（P<.05）下降（7%-15%）。所有运动后 24-72 小时，T 值均显著增加（3%-9%），且每种运动中肌肉内存在异质性。T 值的效应大小和峰值变化以及酸痛感表明，KE 后近端 RF 和 S 及 DW 后中间 VM 受这些运动影响最大。VL 在所有运动后均未出现明显的 T 值增加。这些结果表明，离心 KE 特别导致近端 RF 肌损伤，离心 S 和 DW 导致中间 VM 肌损伤，而 VL 无论何种运动都损伤最小。
