AUTHOR=Wang Lejun , Qiao Minjie , Tao Haifeng , Song Xiaoqian , Shao Qineng , Wang Ce , Yang Hua , Niu Wenxin , Chen Yiqing 

TITLE=A comparison of muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degrees in untrained men

JOURNAL=Frontiers in Physiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.940719

DOI=10.3389/fphys.2022.940719

ISSN=1664-042X

ABSTRACT=The aim of this study was to analyze and compare the muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degree. Twenty-nine untrained male college students performed bench press exercises at intensity of 60% 1RM on three conditions: small unstable bench press with Smith machine (SBP), medium unstable bench press of free weight (FWBP) and large unstable bench press with increased instability by suspending the load with elastic bands (IIBP). One-way repeated-measures analysis of variance was used to compare integrated EMG activity values of biceps brachii (BB), posterior deltoid (PD), triceps brachii long head (TB), anterior deltoid (AD), pectoralis major upper portion (PM) muscles and phase synchronization index (PSI) of BB-TB and PD-AD antagonist muscle pairs. A higher integrated EMG of BB muscle was found during bench press with a more unstable condition. IIBP showed a higher integrated EMG of prime movers (TB, AD and PM) and stabilizing of BB than SBP and FWBP. PSI between muscle pair of BB-TB in gamma frequency band was higher in SBP than the other bench presses with unstable condition, which may be related to the optimal “internal model” for antagonist muscles during bench press exercise. Therefore, IIBP training may be an effective accessory exercise to maintain a higher level of muscle activation across primary and stabilizing muscles with a lighter load for untrained men, while SBP may be a suitable bench press exercise for untrained participants who have not developed the neuromuscular adaptations necessary for correct stabilization of the elbow joint.