Institute of Biomedicine, (IBIOMED), University of León, 24071 León, Spain.
Department of Health Sciences, European University Miguel de Cervantes, 47012 Valladolid, Spain.
Medicina (Kaunas). 2021 May 4;57(5):445. doi: 10.3390/medicina57050445.
To investigate the effects of unilateral accentuated eccentric loading (AEL) on changes in lean mass and function of leg trained (TL) and ipsilateral non-trained arm (NTA) in young men and women. In a prospective trial, 69 Physically active university students (20.2 ± 2.2 years) were randomly placed into a training group ( = 46; 27 men, 19 women) or a control group without training ( = 23; 13 men, 10 women). Participants in the training group performed unilateral AEL in the leg press exercise of the dominant leg twice a week for 10 weeks. An electric motor device-generated isotonic resistance at different intensities for both concentric (30% of 1-RM) and eccentric contractions (105% of 1-RM). Changes in thigh and arm lean tissue mass, unilateral leg press and unilateral elbow flexion maximal concentric (1-RM) and isometric strength (MVIC), and unilateral muscle power at 40, 60, and 80% 1-RM for both leg press and elbow flexion exercises before and after intervention were compared between groups, between sexes and between TL and NTA. Both men and women in the training group showed increases ( < 0.05) in lean tissue mass, 1-RM, MVIC, and muscle power for TL. In NTA, 1-RM, MVIC, and muscle power increased without significant differences between sexes, but neither in men nor women changes in lean tissue mass were observed. In addition, men showed greater changes in TL, but changes in NTA were similar between sexes. No gains in any variable were found for the control group. AEL protocol produced similar neuromuscular changes in TL and ipsilateral NTA, which suggests that strong ipsilateral lower-to-upper limb cross-transfer effects were induced by the eccentric-overload training. However, early ipsilateral increases in muscle force and power were not associated with lean mass gains. Both men and women experienced similar changes in NTA; however, men showed greater changes in TL.
研究单侧加重偏心负荷（AEL）对年轻男性和女性腿部训练（TL）和同侧非训练手臂（NTA）的瘦体重和功能变化的影响。在一项前瞻性试验中，69 名身体活跃的大学生（20.2 ± 2.2 岁）被随机分为训练组（n=46；27 名男性，19 名女性）或无训练对照组（n=23；13 名男性，10 名女性）。训练组参与者每周在主导腿的腿推练习中进行两次单侧 AEL。电动马达设备以不同的强度产生等长（30%1-RM）和偏心收缩（105%1-RM）的等速阻力。干预前后，比较两组、男女之间以及 TL 和 NTA 之间大腿和手臂瘦体重、单侧腿推和单侧肘屈最大等长（1-RM）和等长力量（MVIC）以及单侧 40%、60%和 80%1-RM 的肌肉力量的变化。训练组的男性和女性的 TL 均显示瘦体重、1-RM、MVIC 和肌肉力量增加（<0.05）。在 NTA 中，1-RM、MVIC 和肌肉力量增加，但男女之间没有显著差异，但无论是男性还是女性，瘦体重都没有变化。此外，男性在 TL 中显示出更大的变化，但男女之间的 NTA 变化相似。对照组在任何变量上均未获得收益。AEL 方案在 TL 和同侧 NTA 中产生了相似的神经肌肉变化，这表明偏心过载训练引起了强烈的同侧下至上肢交叉转移效应。然而，早期同侧肌肉力量和力量的增加与瘦体重增加无关。男性和女性在 NTA 中都经历了相似的变化；然而，男性在 TL 中显示出更大的变化。
