Department of Sports and Life Science, National Institute of Fitness and Sports in Kanoya, 1 Shiromizu, Kanoya, Kagoshima, 891-2393, Japan.
Eur J Appl Physiol. 2014 Apr;114(4):663-73. doi: 10.1007/s00421-013-2801-x. Epub 2013 Dec 25.
The present study examined neuromuscular adaptations following 12-week maximal voluntary co-contraction training.
Sixteen young men were allocated to training (TG, n = 9) or control (CG, n = 7) group. TG conducted a training program (3 days/week), which consisted of 4-s maximal voluntary contractions of elbow flexors and extensors by simultaneously contracting both muscle groups at 90° of the elbow joint, followed by 4-s muscle relaxation (10 repetitions/set, 5 sets/day) for 12 weeks. In addition to the muscle thicknesses of elbow flexors and extensors, the torque and electromyograms (EMGs) of the two muscle groups during isometric maximal voluntary contraction (MVC) were determined before (Pre), after 4 weeks, and 12 weeks of intervention.
After intervention, CG showed no significant changes in all measured variables. In TG, MVC torque significantly increased in both elbow flexors (+13 % at 4 weeks and +15 % at 12 weeks) and extensors (+27 % at 4 weeks and +46 % at 12 weeks) from Pre. Muscle thickness also significantly increased in both elbow flexors (+4 %) and extensors (+4 %) at 12 weeks. Agonist EMG activities during MVC significantly increased in both elbow flexors (+31 % at 4 weeks and +44 % at 12 weeks) and extensors (+27 % at 4 weeks and +40 % at 12 weeks), without changes in antagonist involuntary coactivation level in both muscle groups.
These results indicate that maximal voluntary co-contraction is applicable as a training modality for increasing the size and strength of antagonistic muscle pairs without increasing involuntary coactivation level.
本研究旨在探讨 12 周最大自主等长收缩训练后神经肌肉适应性的变化。
16 名年轻男性被分为训练组（TG，n=9）和对照组（CG，n=7）。TG 进行了为期 12 周的训练计划（每周 3 天），包括以 90°的角度同时收缩肘部屈肌和伸肌的 4 秒最大自主收缩，然后是 4 秒肌肉放松（每组 10 次，每天 5 组）。除了测量肘部屈肌和伸肌的肌肉厚度外，在干预前（Pre）、干预 4 周和 12 周后，还测定了两组肌肉在等长最大自主收缩（MVC）期间的扭矩和肌电图（EMG）。
干预后，CG 组所有测量变量均无显著变化。在 TG 组，肘部屈肌（4 周时增加 13%，12 周时增加 15%）和伸肌（4 周时增加 27%，12 周时增加 46%）的 MVC 扭矩均显著增加。肘部屈肌（增加 4%）和伸肌（增加 4%）的肌肉厚度在 12 周时也显著增加。MVC 期间的原动肌 EMG 活动在肘部屈肌（4 周时增加 31%，12 周时增加 44%）和伸肌（4 周时增加 27%，12 周时增加 40%）均显著增加，而两组的拮抗肌无意识协同活动水平无变化。
这些结果表明，最大自主等长收缩可作为一种训练方式，用于增加拮抗肌对的大小和力量，而不会增加无意识协同活动水平。
