Tanimoto Michiya, Ishii Naokata
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902, Japan.
J Appl Physiol (1985). 2006 Apr;100(4):1150-7. doi: 10.1152/japplphysiol.00741.2005. Epub 2005 Dec 8.
We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [ approximately 50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity ( approximately 80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.
我们研究了低强度抗阻运动（伸膝运动），即缓慢动作并产生张力，对肌肉大小和力量的急性和长期影响。预计这种运动类型会增强肌肉内的缺氧环境，而这可能是肌肉肥大的一个因素。将24名无规律运动训练经验的健康年轻男性分为三组（每组n = 8），并进行以下抗阻运动方案：低强度[约为一次重复最大值（1RM）的50%]，缓慢动作并产生张力（离心和向心动作各3秒，停顿1秒，无放松阶段；LST）；高强度（约为80% 1RM），正常速度（向心和离心动作各1秒，放松1秒；HN）；低强度，正常速度（强度与LST相同，速度与HN相同；LN）。在LST和HN组中，平均重复最大值为8RM。在LN组中，强度和运动量与LST组相匹配。每个训练单元包括三组，每周进行三次，共12周。在LST和HN组中，运动训练导致通过MRI测定的横截面积和膝伸肌的等长力量（最大自主收缩）显著（P < 0.05）增加，而在LN组中未观察到显著变化。肌电图和近红外光谱分析表明，一次LST运动可导致持续的肌肉活动，且在三种运动类型中肌肉脱氧程度最大。结果表明，肌肉内的氧环境对运动诱导的肌肉肥大很重要。
