Counts Brittany R, Buckner Samuel L, Dankel Scott J, Jessee Matthew B, Mattocks Kevin T, Mouser J Grant, Laurentino Gilberto C, Loenneke Jeremy P
Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States.
Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, University, MS, United States.
Physiol Behav. 2016 Oct 1;164(Pt A):345-52. doi: 10.1016/j.physbeh.2016.06.024. Epub 2016 Jun 18.
The purpose of the study was to remove the influence of an external load and determine if muscle growth can be elicited by maximally contracting through a full range of motion. In addition, the acute physiologic and perceptual responses to each stimulus were also investigated. Thirteen participants completed 18 sessions of unilateral elbow flexion exercise. Each arm was designated to either NO LOAD or HIGH LOAD condition (70% one repetition maximum). For the NO LOAD condition, participants repeatedly contracted as hard as they could through a full range of motion without the use of an external load. Our results show that anterior muscle thickness increased similarly from Pre to Post, with no differences between conditions for the 50% [Pre: 2.7 (0.8) vs. Post: 2.9 (0.7)], 60% [Pre: 2.9 (0.7) vs. Post: 3.1 (0.7)] or 70% [Pre: 3.2 (0.7) vs. Post: 3.5 (0.7)] sites. There was a significant condition×time interaction for one repetition maximum (p=0.017), with HIGH LOAD (+2.3kg) increasing more than the NO LOAD condition (+1kg). These results extend previous studies that have observed muscle growth across a range of external loads and muscle actions and suggest that muscle growth can occur independent of an external load provided there are enough muscle fibers undergoing mechanotransduction.
该研究的目的是消除外部负荷的影响，并确定通过全范围运动进行最大程度收缩是否能引发肌肉生长。此外，还研究了对每种刺激的急性生理和感知反应。13名参与者完成了18次单侧肘部屈曲运动。每只手臂被指定为无负荷或高负荷条件（70%的一次重复最大值）。在无负荷条件下，参与者在不使用外部负荷的情况下，通过全范围运动尽可能用力地反复收缩。我们的结果表明，从预测试到后测试，前侧肌肉厚度的增加相似，在50%[预测试：2.7（0.8）对后测试：2.9（0.7）]、60%[预测试：2.9（0.7）对后测试：3.1（0.7）]或70%[预测试：3.2（0.7）对后测试：3.5（0.7）]部位，不同条件之间没有差异。一次重复最大值存在显著的条件×时间交互作用（p = 0.017），高负荷组（增加2.3千克）比无负荷组（增加1千克）增加更多。这些结果扩展了先前的研究，这些研究观察了在一系列外部负荷和肌肉动作下的肌肉生长，并表明只要有足够的肌纤维进行机械转导，肌肉生长就可以独立于外部负荷而发生。
