Department of Biology of Physical Activity and Neuromuscular Research Center, University of Jyväskylä, PO Box 35 (VIV), 40014 Jyväskylä, Finland.
Eur J Appl Physiol. 2013 Sep;113(9):2233-44. doi: 10.1007/s00421-013-2653-4. Epub 2013 May 1.
Loading using variable resistance devices, where the external resistance changes in line with the force:angle relationship, has been shown to cause greater acute neuromuscular fatigue and larger serum hormone responses. This may indicate a greater potential for adaptation during long-term training. Twelve (constant resistance group) and 11 (variable resistance group) men completed 20 weeks of resistance training with 10 men as non-training controls. Training-induced adaptations were assessed by bilateral leg press one repetition maximum, a repetition to failure test using 75 % 1RM, lower limb lean mass and vastus lateralis cross-sectional area. Only the variable resistance training group improved the total number of repetitions (41 ± 46 %) and volume load (52 ± 37 %) during the repetition to failure test (P < 0.05). Similar improvements in maximum strength and hypertrophy of the lower limbs were observed in both training groups. Also, constant and variable resistance 5 × 10RM leg press loadings were performed before and after training in a crossover design. Acute loading-induced responses were assessed by concentric and isometric force, serum hormone concentrations and phosphorylation of intramuscular signalling proteins (0-30 min post-loading). Greater acute decreases in force (P < 0.05-0.01), and greater increases in serum testosterone and cortisol concentration (P < 0.05) and ERK 1/2 phosphorylation (P < 0.05) were observed following variable resistance loadings before and after training. Greater training-induced improvements in fatigue resistance occurred in the variable resistance training group, which may be due to greater acute fatigue and physiological responses during variable versus constant resistance loadings.
使用可变电阻装置进行加载，其中外部电阻与力-角度关系一致变化，已被证明会导致更大的急性神经肌肉疲劳和更大的血清激素反应。这可能表明在长期训练中具有更大的适应潜力。12 名（恒阻组）和 11 名（变阻组）男性完成了 20 周的抗阻训练，其中 10 名男性作为非训练对照组。通过双侧腿推 1 次重复最大力量、使用 75%1RM 的重复至力竭测试、下肢瘦体重和股外侧肌横截面积评估训练引起的适应性。只有变阻训练组在重复至力竭测试中增加了总重复次数（41±46%）和容量负荷（52±37%）（P<0.05）。两组训练都观察到下肢最大力量和肥大的相似改善。此外，在交叉设计中，在训练前后进行了恒阻和变阻 5×10RM 腿推负荷。通过等长和向心力、血清激素浓度和肌内信号蛋白磷酸化（加载后 0-30 分钟）评估急性加载诱导的反应。在训练前后进行变阻负荷后，观察到力的急性下降更大（P<0.05-0.01），血清睾酮和皮质醇浓度以及 ERK 1/2 磷酸化增加更大（P<0.05）。变阻训练组发生了更大的疲劳抵抗的训练诱导改善，这可能是由于变阻负荷与恒阻负荷相比，急性疲劳和生理反应更大。
