Wang Lejun, Tao Haifeng, Chen Qing, Qiao Minjie, Song Xiaoqian, Niu Wenxin
Sport and Health Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Physical Education Department, Tongji University, Shanghai, China.
School of Medicine, Tongji University, Shanghai, China.
Front Hum Neurosci. 2024 Oct 22;18:1472075. doi: 10.3389/fnhum.2024.1472075. eCollection 2024.
To explore the neuromuscular control mechanism and quantifying the fatigue response during bench press exercise is important references to prescribe an appropriate exercise program. However, current literature struggles to provide a concrete conclusion on the changes of intermuscular EMG-EMG coupling between synergistic and antagonist muscles during the exercise. Thus, the current study was designed to reveal fatigue-related changes of intermuscular EMG-EMG coupling during bench press exercise.
Thirty-one healthy male participants performed a bench press exercise on the Smith machine at 60% One Repetition Maximum (1RM) workload to exhaustion, while surface electromyographic signals (sEMG) were collected from triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD), posterior deltoid (PD), and pectoralis major (PM). Surface EMG signals were divided into the first half and second half of the bench press exercise. Phase synchronization index (PSI) was calculated between sEMG of synergistic muscle pairs AD-TB, AD-PM and antagonist muscle pairs BB-TB, AD-PD.
EMG power of TB, AD, PD, PM muscles in alpha (8-12 Hz) frequency band and EMG power of each muscle in beta (15-35 Hz), and gamma (35-60 Hz) frequency bands were all increased during the second half of contraction compared with the first half of contraction. PSI of gamma frequency band was significantly decreased in BB-TB muscle pair while EMG-EMG coupling of AD-TB in gamma frequency band was significantly increased during the second half of contraction compared to the first half of contraction.
The results indicated a decrease of interconnection between synchronized cortical neurons and the motoneuron pool of BB and TB, and an increase of interconnection between AD-TB muscles during fatiguing bench press exercise at 60% 1RM workload. The changes of intermuscular coupling may be related to the supraspinal modulations to compensate for the decrease of muscle force as well as a result of unbalanced changes of agonist and antagonist muscle contractility.
探究神经肌肉控制机制并量化卧推运动期间的疲劳反应，对于制定合适的运动计划具有重要参考价值。然而，目前的文献难以就运动期间协同肌和拮抗肌之间肌间肌电图 - 肌电图耦合的变化得出具体结论。因此，本研究旨在揭示卧推运动期间与疲劳相关的肌间肌电图 - 肌电图耦合变化。
31名健康男性参与者在史密斯机上以60%的一次重复最大值（1RM）负荷进行卧推运动直至力竭，同时从肱三头肌（TB）、肱二头肌（BB）、三角肌前束（AD）、三角肌后束（PD）和胸大肌（PM）采集表面肌电信号（sEMG）。表面肌电信号被分为卧推运动的前半段和后半段。计算协同肌对AD - TB、AD - PM以及拮抗肌对BB - TB、AD - PD的sEMG之间的相位同步指数（PSI）。
与收缩前半段相比，收缩后半段TB、AD、PD、PM肌肉在α（8 - 12Hz）频段的肌电功率以及各肌肉在β（15 - 35Hz）和γ（35 - 60Hz）频段的肌电功率均增加。与收缩前半段相比，收缩后半段BB - TB肌肉对的γ频段PSI显著降低，而AD - TB在γ频段的肌电图 - 肌电图耦合显著增加。
结果表明，在60% 1RM负荷的疲劳卧推运动中，同步皮层神经元与BB和TB运动神经元池之间的连接减少，而AD - TB肌肉之间的连接增加。肌间耦合的变化可能与脊髓上调制有关，以补偿肌肉力量的下降，也是拮抗肌和主动肌收缩性不平衡变化的结果。
