Rahbek Stine Klejs, Farup Jean, Møller Andreas Buch, Vendelbo Mikkel Holm, Holm Lars, Jessen Niels, Vissing Kristian
Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, Aarhus C, 8000, Aarhus, Denmark.
Amino Acids. 2014 Oct;46(10):2377-92. doi: 10.1007/s00726-014-1792-1. Epub 2014 Jul 9.
Greater force produced with eccentric (ECC) compared to concentric (CONC) contractions, may comprise a stronger driver of muscle growth, which may be further augmented by protein supplementation. We investigated the effect of differentiated contraction mode with either whey protein hydrolysate and carbohydrate (WPH + CHO) or isocaloric carbohydrate (CHO) supplementation on regulation of anabolic signalling, muscle protein synthesis (MPS) and muscle hypertrophy. Twenty-four human participants performed unilateral isolated maximal ECC versus CONC contractions during exercise habituation, single-bout exercise and 12 weeks of training combined with WPH + CHO or CHO supplements. In the exercise-habituated state, p-mTOR, p-p70S6K, p-rpS6 increased by approximately 42, 206 and 213 %, respectively, at 1 h post-exercise, with resistance exercise per se; whereas, the phosphorylation was exclusively maintained with ECC at 3 and 5 h post-exercise. This acute anabolic signalling response did not differ between the isocaloric supplement types, neither did protein fractional synthesis rate differ between interventions. Twelve weeks of ECC as well as CONC resistance training augmented hypertrophy with WPH + CHO group compared to the CHO group (7.3 ± 1.0 versus 3.4 ± 0.8 %), independently of exercise contraction type. Training did not produce major changes in basal levels of Akt-mTOR pathway components. In conclusion, maximal ECC contraction mode may constitute a superior driver of acute anabolic signalling that may not be mirrored in the muscle protein synthesis rate. Furthermore, with prolonged high-volume resistance training, contraction mode seems less influential on the magnitude of muscle hypertrophy, whereas protein and carbohydrate supplementation augments muscle hypertrophy as compared to isocaloric carbohydrate supplementation .
与向心（CONC）收缩相比，离心（ECC）收缩产生的力量更大，可能是肌肉生长的更强驱动因素，补充蛋白质可能会进一步增强这种作用。我们研究了不同的收缩模式，以及补充乳清蛋白水解物和碳水化合物（WPH + CHO）或等热量碳水化合物（CHO）对合成代谢信号传导调节、肌肉蛋白质合成（MPS）和肌肉肥大的影响。24名人类参与者在运动适应期、单次运动和12周训练期间，进行了单侧孤立的最大ECC与CONC收缩，并同时补充WPH + CHO或CHO。在运动适应状态下，运动后1小时，p-mTOR、p-p70S6K、p-rpS6分别增加了约42%、206%和213%，这是由抗阻运动本身引起的；而在运动后3小时和5小时，只有ECC能维持磷酸化。这种急性合成代谢信号反应在等热量补充剂类型之间没有差异，干预之间的蛋白质分数合成率也没有差异。与CHO组相比，WPH + CHO组进行12周的ECC以及CONC抗阻训练后，肌肉肥大增加（7.3±1.0%对3.4±0.8%），与运动收缩类型无关。训练并未使Akt-mTOR信号通路成分的基础水平发生重大变化。总之，最大ECC收缩模式可能是急性合成代谢信号的优越驱动因素，而这可能不会反映在肌肉蛋白质合成率上。此外，在长时间的大运动量抗阻训练中，收缩模式对肌肉肥大程度的影响似乎较小，而与等热量碳水化合物补充相比，补充蛋白质和碳水化合物可增强肌肉肥大。
