Watanabe Yuya, Madarame Haruhiko, Ogasawara Riki, Nakazato Koichi, Ishii Naokata
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
Clin Physiol Funct Imaging. 2014 Nov;34(6):463-70. doi: 10.1111/cpf.12117. Epub 2013 Dec 4.
We previously reported that low-intensity [50% of one repetition maximum (1RM)] resistance training with slow movement and tonic force generation (LST) causes muscle hypertrophy and strength gain in older participants. The aim of this study was to determine whether resistance training with slow movement and much more reduced intensity (30%1RM) increases muscle size and strength in older adults. Eighteen participants (60-77 years) were randomly assigned to two groups. One group performed very low-intensity (30% 1RM) knee extension exercise with continuous muscle contraction (LST: 3-s eccentric, 3-s concentric, and 1-s isometric actions with no rest between each repetition) twice a week for 12 weeks. The other group underwent intermitted muscle contraction (CON: 1-s concentric and 1-s eccentric actions with 1-s rest between each repetition) for the same time period. The 1RM, isometric and isokinetic strengths, and cross-sectional image of the mid-thigh obtained by magnetic resonance imaging were examined before and after the intervention. LST significantly increased the cross-sectional area of the quadriceps muscle (5.0%, P<0.001) and isometric and isokinetic knee extension strengths (P<0.05). CON failed to increase muscle size (1.1%, P = 0.12), but significantly improved its strength (P<0.05). These results indicate that even if the intensity is as low as 30% 1RM, LST can increase muscle size and strength in healthy older adults. The large total contraction time may be related to muscle hypertrophy and strength gain. LST would be useful for preventing sarcopenia in older individuals.
我们之前报道过，低强度[1次重复最大值（1RM）的50%]且伴有缓慢动作和持续性力量产生的抗阻训练（LST）可使老年参与者的肌肉肥大并增强力量。本研究的目的是确定缓慢动作且强度更低（30%1RM）的抗阻训练是否能增加老年人的肌肉尺寸和力量。18名参与者（60 - 77岁）被随机分为两组。一组每周进行两次非常低强度（30%1RM）的膝关节伸展运动，伴有持续肌肉收缩（LST：3秒离心、3秒向心以及1秒等长动作，每次重复之间无休息），共持续12周。另一组在相同时间段内进行间歇性肌肉收缩（CON：1秒向心和1秒离心动作，每次重复之间休息1秒）。在干预前后检测1RM、等长和等速力量，以及通过磁共振成像获得的大腿中部横截面图像。LST显著增加了股四头肌的横截面积（5.0%，P<0.001）以及等长和等速膝关节伸展力量（P<0.05）。CON未能增加肌肉尺寸（1.1%，P = 0.12），但显著提高了其力量（P<0.05）。这些结果表明，即使强度低至30%1RM，LST仍可增加健康老年人的肌肉尺寸和力量。总的收缩时间较长可能与肌肉肥大和力量增加有关。LST对于预防老年人肌肉减少症可能有用。
