Exercise Physiology Laboratory and Center for Sport Performance, Department of Kinesiology, California, USA.
J Strength Cond Res. 2012 May;26(5):1296-301. doi: 10.1519/JSC.0b013e31822e7a85.
The purpose of this study was to determine if an active warm-up affects peak torque (PT), rate of torque development (RTD), and the electromyographic (EMG) and mechanomyographic (MMG) signals. Twenty-one men (mean age ± SD: 24.0 ± 2.7 years) visited the exercise physiology laboratory on 2 occasions. During the first visit, they either performed an active warm-up (10 minutes of stationary cycling at 70% of predicted maximum heart rate) or sat quietly (no warm-up). Participants were then tested for isometric and isokinetic (60°, 180°, and 300°·s) PT, and RTD (measured as S-gradient) on an isokinetic dynamometer. Electromyographic and MMG sensors were placed over the vastus lateralis muscle to monitor the electrical and mechanical aspects of muscle contractions, respectively. The testing protocol used for the first visit was repeated for the second visit, but the preexercise treatment (warm-up, no warm-up) not given during the first visit was administered. The results indicated that an active warm-up did not affect PT, RTD, or measures of muscle activation as reflected by EMG amplitude, EMG frequency, or MMG frequency (p > 0.05). However, MMG amplitude at 180°·s was significantly greater in the warm-up condition compared with the no warm-up condition. The isolated increase in MMG amplitude suggested that warm-up may have affected the mechanical properties of muscle by reducing muscular stiffness or decreasing intramuscular fluid pressure, but that it was not sufficient to influence performance.
本研究旨在确定主动热身是否会影响峰值扭矩（PT）、扭矩发展速率（RTD）以及肌电图（EMG）和机械肌电图（MMG）信号。21 名男性（平均年龄±标准差：24.0±2.7 岁）在 2 次访问时访问了运动生理学实验室。在第一次访问时，他们要么进行主动热身（以预测最大心率的 70%进行 10 分钟的固定自行车运动），要么安静地坐着（不热身）。然后，参与者在等速测力计上进行等长和等速（60°、180°和 300°·s）PT 和 RTD（测量为 S-梯度）测试。肌电图和 MMG 传感器放置在股外侧肌上，分别监测肌肉收缩的电和机械方面。第一次访问时使用的测试方案在第二次访问时重复，但第一次访问时未进行的预运动处理（热身、不热身）在第二次访问时进行。结果表明，主动热身不会影响 PT、RTD 或 EMG 幅度、EMG 频率或 MMG 频率等肌肉激活的指标（p>0.05）。然而，在热身条件下，180°·s 时的 MMG 幅度明显大于无热身条件。孤立的 MMG 幅度增加表明，热身可能通过降低肌肉僵硬或减少肌肉内液压力来影响肌肉的机械特性，但不足以影响性能。
