Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, The University of Mississippi, P.O. Box 1848, University, MS, 38677, USA.
Eur J Appl Physiol. 2017 Nov;117(11):2125-2135. doi: 10.1007/s00421-017-3690-1. Epub 2017 Aug 3.
Many reviews conclude that metabolites play an important role with respect to muscle hypertrophy during resistance exercise, but their actual physiologic contribution remains unknown. Some have suggested that metabolites may work independently of muscle contraction, while others have suggested that metabolites may play a secondary role in their ability to augment muscle activation via inducing fatigue. Interestingly, the studies used as support for an anabolic role of metabolites use protocols that are not actually designed to test the importance of metabolites independent of muscle contraction. While there is some evidence in vitro that metabolites may induce muscle hypertrophy, the only study attempting to answer this question in humans found no added benefit of pooling metabolites within the muscle post-exercise. As load-induced muscle hypertrophy is thought to work via mechanotransduction (as opposed to being metabolically driven), it seems likely that metabolites simply augment muscle activation and cause the mechanotransduction cascade in a larger proportion of muscle fibers, thereby producing greater muscle growth. A sufficient time under tension also appears necessary, as measurable muscle growth is not observed after repeated maximal testing. Based on current evidence, it is our opinion that metabolites produced during resistance exercise do not have anabolic properties per se, but may be anabolic in their ability to augment muscle activation. Future studies are needed to compare protocols which produce similar levels of muscle activation, but differ in the magnitude of metabolites produced, or duration in which the exercised muscles are exposed to metabolites.
许多综述得出结论，代谢物在抗阻运动期间肌肉肥大方面发挥着重要作用，但它们的实际生理贡献仍不清楚。一些人认为代谢物可能独立于肌肉收缩起作用，而另一些人则认为代谢物可能通过诱导疲劳在增强肌肉激活方面发挥次要作用。有趣的是，作为代谢物具有合成代谢作用的支持研究使用的方案实际上并不是为了测试代谢物独立于肌肉收缩的重要性而设计的。虽然有一些体外证据表明代谢物可能诱导肌肉肥大，但唯一一项试图在人体中回答这个问题的研究发现，在运动后将代谢物集中在肌肉中并没有额外的好处。由于负荷诱导的肌肉肥大被认为是通过机械转导起作用的（而不是代谢驱动的），因此代谢物似乎只是增强肌肉激活，并在更大比例的肌肉纤维中引起机械转导级联反应，从而产生更大的肌肉生长。足够的张力时间似乎也是必要的，因为在反复最大测试后不会观察到可测量的肌肉生长。基于目前的证据，我们认为，在抗阻运动期间产生的代谢物本身并没有合成代谢特性，但可能具有增强肌肉激活的合成代谢能力。未来的研究需要比较产生相似肌肉激活水平但代谢物产生幅度或运动肌肉暴露于代谢物的时间不同的方案。
