Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil.
J Biomech. 2020 Jan 2;98:109465. doi: 10.1016/j.jbiomech.2019.109465. Epub 2019 Oct 31.
The present study compared neuromuscular activation, measured by surface electromyography (EMG) amplitude [measure by EMG peak (EMG)] and range of motion (ROM) where EMG occurred between two training protocols, matched by time under tension, but with a different number and duration of repetitions. Sixteen recreationally trained males performed 2 training protocols with 3 sets, 180 s of rest with 60% of one-repetition maximum(1RM) on the bench press performed in a Smith machine. Protocol A consisted of 6 repetitions with a repetition duration of 6 s and protocol B consisted of 12 repetitions with a repetition duration of 3 s. EMG activity of anterior deltoid, pectoralis major and triceps brachii muscles were recorded. The results showed a general higher EMG amplitude (regardless of the muscle) in protocol B (p = 0.010), and pectoral and triceps brachii consistently presented higher neuromuscular activation than anterior deltoid at both protocols (p = 0.007). Additionally, the ROM where EMG occurred in triceps brachii was in the middle of the concentric action (50% of ROM), this occurred in the first half of the same action (24% of ROM) in the other muscles. In conclusion, protocol B demonstrated an increased EMG amplitude over protocol A, although both protocols responded similarly by achieving the highest EMG amplitude at same ROM among the muscles analysed.
本研究比较了两种训练方案的神经肌肉激活情况，这两种方案通过表面肌电图（EMG）幅度[通过 EMG 峰值（EMG）测量]和运动范围（ROM）来衡量，这两种方案的持续时间相同，但重复次数和持续时间不同。16 名有经验的男性在史密斯机上以 60%的 1 次重复最大重量（1RM）进行了 3 组、每组 180 秒的休息，完成了两种训练方案。方案 A 由 6 次重复组成，每次重复持续 6 秒，方案 B 由 12 次重复组成，每次重复持续 3 秒。记录了三角肌前束、胸大肌和肱三头肌的肌电图活动。结果显示，方案 B 的肌电图幅度普遍较高（与肌肉无关）（p=0.010），且在两个方案中，胸大肌和肱三头肌的神经肌肉激活始终高于三角肌（p=0.007）。此外，肱三头肌的肌电图发生的 ROM 处于向心运动的中间位置（ROM 的 50%），而在其他肌肉中，相同的运动的前半部分（ROM 的 24%）发生了相同的情况。总之，方案 B 的 EMG 幅度高于方案 A，尽管两种方案通过在分析的肌肉中达到相同 ROM 时获得最大的 EMG 幅度来产生相似的反应。
