Wong Vickie, Spitz Robert W, Bentley John P, Song Jun Seob, Yamada Yujiro, Kataoka Ryo, Hammert William B, Seffrin Aldo, Bell Zachary W, Loenneke Jeremy P
Department of Sport and Health, Solent University, Southampton, Hampshire, UNITED KINGDOM.
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS.
Med Sci Sports Exerc. 2025 Apr 1;57(4):867-875. doi: 10.1249/MSS.0000000000003613. Epub 2024 Nov 28.
To determine 1) whether the relationship between isometric training and muscle growth depends on baseline blood flow or is mediated by a change in blood flow, and 2) whether muscle growth mediates changes in maximal isometric strength.
A total of 179 participants were randomized into low-intensity isometric handgrip exercise (LI), low-intensity isometric handgrip exercise with blood flow restriction (LI-BFR), maximal handgrip exercise (MAX), and a non-exercise control (CONTROL). Muscle thickness, strength, and resting limb blood flow were measured before and after the 6-wk intervention.
Baseline blood flow did not moderate training effects on muscle thickness changes (MTHchg) ( P = 0.666), and moderated mediation tests were nonsignificant. Although the LI-BFR group showed a significant effect on MTHchg ( P = 0.018), MTHchg was not significantly related to handgrip strength change (HGchg) ( P = 0.281), suggesting no mediation of the training-to-strength effect by MTHchg. Both the LI-BFR ( P = 0.004) and MAX ( P < 0.001) groups exhibited positive direct effects on HGchg compared with CONTROL. Furthermore, there were no differences between training groups and CONTROL on blood flow change (BFchg), BFchg and MTHchg were not significantly related, and neither BFchg nor MTHchg predicted HGchg, providing no evidence for mediated pathways.
Muscle growth may not have occurred to an extent that would require vascular adaptation. Training maximally induced the greatest strength adaptations but was seemingly not driven by muscle growth.
1）确定等长训练与肌肉生长之间的关系是否取决于基线血流量或由血流量变化介导；2）确定肌肉生长是否介导最大等长力量的变化。
179名参与者被随机分为低强度等长握力运动组（LI）、低强度等长握力运动加血流限制组（LI-BFR）、最大握力运动组（MAX）和非运动对照组（CONTROL）。在为期6周的干预前后测量肌肉厚度、力量和静息肢体血流量。
基线血流量并未调节训练对肌肉厚度变化（MTHchg）的影响（P = 0.666），且调节中介检验无统计学意义。尽管LI-BFR组对MTHchg有显著影响（P = 0.018），但MTHchg与握力变化（HGchg）无显著相关性（P = 0.281），表明MTHchg未介导训练到力量的效应。与CONTROL组相比，LI-BFR组（P = 0.004）和MAX组（P < 0.001）对HGchg均表现出正向直接效应。此外，训练组与CONTROL组在血流量变化（BFchg）方面无差异，BFchg与MTHchg无显著相关性，且BFchg和MTHchg均不能预测HGchg，未提供介导途径的证据。
肌肉生长可能未达到需要血管适应的程度。最大程度的训练诱导了最大的力量适应，但似乎并非由肌肉生长驱动。
