Muscle activation with swinging loads in bench press

The aim of the study was to compare the EMG amplitude in bench press (stable loads) to bench press using loads moving in anteroposterior and mediolateral directions. Seventeen resistance-trained men, with 9.4 +/- 4.7 years of resistance training experience were recruited. After a familiarization session assessing 1 repetition maximum (RM) in the bench press, participants performed: 1) bench press with traditional stable loading 2) bench press with loads (2x5kg) attached as pendulums swinging forward/backwards and 3) left/right in randomized order. The total load was 70% of the 1RM load. Electromyography was measured in the pectoralis major, anterior- and posterior deltoid, biceps brachii, triceps brachii and external obliques. Using stable loads, the pectoralis major demonstrated lower EMG amplitude compared to the two unstable conditions. In the external obliques, the stable conditions demonstrated lower EMG amplitude than the swing in the mediolateral direction, but not the anteroposterior direction. There were no differences between two swinging loads or the three conditions for the triceps brachii, biceps brachii, anterior deltoid or posterior deltoid. In conclusion, swinging in bench press resulted in similar EMG amplitude in the shoulder- and arm muscles, but greater pectoralis and external oblique (only mediolateral swing) activity compared to bench press.