Department of Kinesiology, McMaster University, Hamilton, ON L8S 4L8, Canada.
Nutrients. 2018 Feb 7;10(2):180. doi: 10.3390/nu10020180.
Skeletal muscle supports locomotion and serves as the largest site of postprandial glucose disposal; thus it is a critical organ for physical and metabolic health. Skeletal muscle mass is regulated by the processes of muscle protein synthesis (MPS) and muscle protein breakdown (MPB), both of which are sensitive to external loading and aminoacidemia. Hyperaminoacidemia results in a robust but transient increase in rates of MPS and a mild suppression of MPB. Resistance exercise potentiates the aminoacidemia-induced rise in MPS that, when repeated over time, results in gradual radial growth of skeletal muscle (i.e., hypertrophy). Factors that affect MPS include both quantity and composition of the amino acid source. Specifically, MPS is stimulated in a dose-responsive manner and the primary amino acid agonist of this process is leucine. MPB also appears to be regulated in part by protein intake, which can exert a suppressive effect on MPB. At high protein doses the suppression of MPB may interfere with skeletal muscle adaptation following resistance exercise. In this review, we examine recent advancements in our understanding of how protein ingestion impacts skeletal muscle growth following resistance exercise in young adults during energy balance and energy restriction. We also provide practical recommendations for exercisers who wish to maximize the hypertrophic response of skeletal muscle during resistance exercise training.
骨骼肌支持运动，是餐后葡萄糖摄取的最大部位；因此，它是身体健康和新陈代谢的关键器官。骨骼肌质量受肌肉蛋白质合成（MPS）和肌肉蛋白质分解（MPB）的调节，这两个过程都对外界负荷和氨基酸血症敏感。高氨基酸血症会导致 MPS 率的显著但短暂增加，同时轻度抑制 MPB。抗阻运动可增强氨基酸血症引起的 MPS 升高，随着时间的推移，这会导致骨骼肌逐渐径向生长（即，肥大）。影响 MPS 的因素包括氨基酸来源的数量和组成。具体来说，MPS 以剂量反应的方式受到刺激，该过程的主要氨基酸激动剂是亮氨酸。MPB 的调节似乎部分受到蛋白质摄入的影响，它可以对 MPB 产生抑制作用。在高蛋白质剂量下，MPB 的抑制可能会干扰抗阻运动后骨骼肌的适应。在这篇综述中，我们研究了关于蛋白质摄入如何影响年轻人在能量平衡和能量限制期间进行抗阻运动后的骨骼肌生长的最新进展。我们还为希望在抗阻运动训练中最大限度地提高骨骼肌肥大反应的运动员提供了实用建议。
