Chen Trevor C, Tseng Wei-Chin, Chen Hsin-Lian, Tseng Kuo-Wei, Chou Tai-Ying, Huang Yuh-Chuan, Nosaka Kazunori
Department of Physical Education, National Taiwan Normal University, Taipei City, Taiwan.
Department of Exercise and Health Sciences, University of Taipei, Taipei City, Taiwan.
Appl Physiol Nutr Metab. 2021 Aug;46(8):897-905. doi: 10.1139/apnm-2020-1016. Epub 2021 Feb 12.
We investigated the effects of repeating 30 low-intensity eccentric contractions with a dumbbell corresponding to 10% maximal isometric strength (10%EC) on muscle strength and hypertrophy, and muscle damage after 30 maximal eccentric contractions (MaxEC) of the elbow flexors. Young men were placed into 1 of 3 experimental groups that performed 10%EC either once, twice a week for 4 (8 bouts) or 8 weeks (16 bouts) before MaxEC, or a control group that performed 2 bouts of MaxEC separated by 2 weeks ( = 13/group). Repeating 16 bouts of 10%EC increased ( < 0.05) maximal voluntary contraction strength (30 ± 21%) and muscle thickness (4.2 ± 2.3%) greater than 8 bouts (16 ± 4%, 1.9 ± 1.3%). Changes in the muscle damage markers after MaxEC were smaller ( < 0.05) for the experimental groups than the control group, and the magnitude of muscle damage protection was greater ( < 0.05) after 16 bouts (65 ± 30%) than 8 bouts (55 ± 33%), followed by 1 bout (34 ± 27%). The protection by 16 bouts was similar ( = 0.81) to that shown by the second MaxEC of the control group. These results showed that 10%EC produced potent muscle adaptation effects accumulatively and conferred muscle damage protection, but 1 bout of 10%EC was still effective for conferring approximately 20% of the protection of that by 16 bouts. Repeating low-intensity eccentric exercise induces large increases in muscle strength and hypertrophy. Low-intensity eccentric exercise protects muscle damage induced by maximal eccentric contractions, and the protection is reinforced by repeating it. These are especially beneficial for individuals who are frail and cannot tolerate high-intensity resistance training.
我们研究了使用相当于最大等长力量10%的哑铃重复进行30次低强度离心收缩（10%EC）对肌肉力量、肥大以及肘部屈肌进行30次最大离心收缩（MaxEC）后的肌肉损伤的影响。年轻男性被分为3个实验组中的1组，其中一组在MaxEC前每周进行1次、持续4周（8次）或8周（16次）的10%EC，另一组为对照组，进行2次间隔2周的MaxEC（每组 = 13人）。重复16次10%EC比8次（16 ± 4%，1.9 ± 1.3%）能更大程度地增加（P < 0.05）最大自主收缩力量（30 ± 21%）和肌肉厚度（4.2 ± 2.3%）。MaxEC后，实验组的肌肉损伤标志物变化比对照组小（P < 0.05），且16次（65 ± 30%）后的肌肉损伤保护程度比8次（55 ± 33%）更大（P < 0.05），其次是1次（34 ± 27%）。16次的保护效果与对照组第二次MaxEC的保护效果相似（P = 0.81）。这些结果表明，10%EC能累积产生强大的肌肉适应效应并提供肌肉损伤保护，但1次10%EC仍能提供约16次保护效果的20%。重复低强度离心运动可使肌肉力量和肥大大幅增加。低强度离心运动可保护由最大离心收缩引起的肌肉损伤，且通过重复可增强这种保护作用。这对体弱且无法耐受高强度抗阻训练的个体尤其有益。
