Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Australia.
School of Medicine, University of Zagreb, Zagreb, Croatia.
Med Hypotheses. 2018 Mar;112:40-42. doi: 10.1016/j.mehy.2018.01.012. Epub 2018 Feb 2.
An emerging body of evidence is starting to suggest that the hypertrophy of skeletal muscle fibers might be load specific. In other words, it may be that resistance training with high loads (i.e., ≥60% of 1 repetition maximum [RM]) emphasizes a greater growth of type II muscle fibers, while resistance training with low loads (i.e., <60% of 1RM) might primarily augment hypertrophy of type I muscle fibers. Type I and type II muscle fibers possess certain distinct characteristics, with type II muscle fibers having faster calcium kinetics, faster shortening velocities, and ability to generate more power than type I muscle fibers. Alternatively, compared to type II fibers, type I muscle fibers have a higher oxidative capacity and a higher fatigue threshold. Due to the lower fatigability of type I muscle fibers, it may be hypothesized that a greater time under load is necessary to stimulate an accentuated growth of these fibers. An increase in time under load can be achieved when training with lower loads (e.g., 30% of 1RM) and to momentary muscular failure. The present paper discusses the hypothesis that a greater hypertrophy of type I muscle fibers may be induced with low load resistance training.
越来越多的证据表明，骨骼肌纤维的肥大可能具有负荷特异性。换句话说，高负荷（即≥1 重复最大负荷 [RM] 的 60%）的抗阻训练可能更强调 II 型肌纤维的生长，而低负荷（即<60%的 1RM）的抗阻训练可能主要增强 I 型肌纤维的肥大。I 型和 II 型肌纤维具有某些明显的特征，II 型肌纤维具有更快的钙动力学、更快的缩短速度和比 I 型肌纤维产生更大力量的能力。相比之下，与 II 型纤维相比，I 型肌纤维具有更高的氧化能力和更高的疲劳阈值。由于 I 型肌纤维的疲劳性较低，可以假设需要更长的时间施加负荷才能刺激这些纤维的显著生长。通过使用较低的负荷（例如 1RM 的 30%）和达到瞬间肌肉疲劳，可以增加负荷下的时间。本文讨论了这样一种假设，即低负荷抗阻训练可能会引起 I 型肌纤维更大的肥大。
