Department of Physical Education, National Taiwan Normal University, Taiwan.
Department of Physical Education, Health and Recreation, National Chiayi University, Taiwan.
J Sci Med Sport. 2018 Oct;21(10):1068-1072. doi: 10.1016/j.jsams.2017.12.012. Epub 2017 Dec 29.
The magnitude of muscle damage induced by maximal eccentric contractions (MaxEC) of the elbow flexors (EF) is reduced when it is preceded by low-intensity (10% of maximal voluntary isometric contraction strength) eccentric contractions (10%EC) of the same muscle, or by MaxEC of the opposite EF. This study investigated whether 10%EC would reduce the magnitude of muscle damage after MaxEC performed by the opposite arm.
Comparison among 6 groups for changes in indirect markers of muscle damage.
Young (21.0±1.8years) untrained men were assigned to five experimental groups (n=13/group) that performed 30, 10%EC followed by 30 MaxEC of the other arm performed at either 1 (1d), 2 (2d), 7 (1wk), 14 (2wk) or 21days (3wk) later, and one control group that performed 30 MaxEC without 10%EC (n=13). Changes in several indirect markers of muscle damage after MaxEC were compared among the groups by mixed-design two-way ANOVAs.
No significant changes in maximal voluntary concentric contraction torque, plasma creatine kinase activity and muscle soreness were evident after 10%EC. Changes in these variables after MaxEC were smaller (p<0.05) for the 1d, 2d and 1wk groups than control group, without significant differences between the 1d, 2d and 1wk groups. No significance differences in the changes were evident among the 2wk, 3wk and control groups, except for muscle soreness showing smaller (p<0.05) increases for the 2wk and 3wk groups than control group.
These results showed that 10%EC conferred muscle damage protection to the contralateral arm that performed MaxEC.
当肘屈肌（EF）进行最大离心收缩（MaxEC）之前先进行低强度（最大自主等长收缩强度的 10%）离心收缩（10%EC），或者对相反的 EF 进行 MaxEC，会降低肌肉损伤的程度。本研究探讨了对侧手臂进行 MaxEC 后，10%EC 是否会降低肌肉损伤的程度。
比较 6 组间接肌肉损伤标志物的变化。
将年轻（21.0±1.8 岁）未经训练的男性分为 5 个实验组（每组 13 人），每组进行 30 次最大离心收缩，然后进行 30 次对侧手臂的 10%EC，分别在 1（1d）、2（2d）、7（1wk）、14（2wk）或 21 天后（3wk）进行，对照组进行 30 次最大离心收缩，不进行 10%EC（每组 13 人）。采用混合设计双向方差分析比较各组 MaxEC 后几种间接肌肉损伤标志物的变化。
10%EC 后，最大自主向心收缩扭矩、血浆肌酸激酶活性和肌肉酸痛均无明显变化。与对照组相比，1d、2d 和 1wk 组这些变量在 MaxEC 后的变化较小（p<0.05），但 1d、2d 和 1wk 组之间无显著差异。除肌肉酸痛外，2wk、3wk 和对照组之间的变化无显著差异，2wk 和 3wk 组的肌肉酸痛增加较小（p<0.05）。
这些结果表明，10%EC 对进行 MaxEC 的对侧手臂有肌肉损伤保护作用。
