Nosaka K, Sakamoto K, Newton M, Sacco P
Exercise and Sports Science, Graduate School of Integrated Science, Yokohama City University, Yokohama, Japan.
Med Sci Sports Exerc. 2001 Sep;33(9):1490-5. doi: 10.1097/00005768-200109000-00011.
One bout of eccentric exercise produces an adaptation that reduces muscle damage in subsequent bouts. Because it is not known how long this adaptation lasts, the present study investigated the maximal length of the attenuated changes in muscle damage indicators after high-force eccentric exercise.
Male students (N = 35) were placed into three groups and performed two bouts of eccentric exercise of the nondominant elbow flexors separated by either 6 (N = 14), 9 (N = 11), or 12 (N = 10) months. Maximal isometric force (MIF), range of motion (ROM), upper arm circumference (CIR), muscle soreness (SOR), and plasma creatine kinase activity (CK) were measured before and for 5 d after exercise. Magnetic resonance (MR) images of the transverse and longitudinal scans of the upper arm were taken 4 d after exercise. Changes in the criterion measures were compared between the first and second bouts and between groups by a two-way repeated measures ANOVA.
A faster recovery in MIF was evident after a second bout performed at 6 or 9 months, and reduced SOR as well as smaller increases in CIR, CK, and T2 relaxation time of MR images also occurred after the second exercise bout at 6 months compared with initial responses. No significant differences between the bouts were found for ROM, and the 12-month group did not show any repeated bout effect.
These results show that the repeated bout effect for most of the criterion measures lasts at least 6 months but is lost between 9 and 12 months.
一次离心运动可产生一种适应性变化，从而减少后续运动中的肌肉损伤。由于尚不清楚这种适应性变化能持续多久，本研究调查了高强度离心运动后肌肉损伤指标减弱变化的最长持续时间。
将35名男学生分为三组，对非优势侧肘屈肌进行两次离心运动，两次运动间隔分别为6个月（n = 14）、9个月（n = 11）或12个月（n = 10）。在运动前及运动后5天测量最大等长肌力（MIF）、活动范围（ROM）、上臂围（CIR）、肌肉酸痛（SOR）和血浆肌酸激酶活性（CK）。在运动后4天拍摄上臂横断和纵断扫描的磁共振（MR）图像。通过双向重复测量方差分析比较第一次和第二次运动以及各组之间标准测量指标的变化。
在6个月或9个月后进行第二次运动时，MIF恢复更快，与初始反应相比，6个月后进行第二次运动时，SOR减轻，CIR、CK和MR图像T2弛豫时间增加幅度也更小。ROM在两次运动之间未发现显著差异，12个月组未显示任何重复运动效应。
这些结果表明，大多数标准测量指标的重复运动效应至少持续6个月，但在9至12个月之间消失。
