Muscle activation with swinging loads in bench press

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• The bench press is a fundamental resistance exercise.
• Investigating muscle activation during variations of the bench press can optimize training.
• Understanding how unstable loads affect muscle engagement is crucial for exercise prescription.

Purpose of the Study:

• To compare electromyography (EMG) amplitude in the bench press with stable loads versus loads moving in anteroposterior and mediolateral directions.
• To determine the impact of swinging loads on key upper body and core muscle activation.

Main Methods:

• Seventeen resistance-trained men performed the bench press with stable loads, anteroposterior swinging loads, and mediolateral swinging loads at 70% of their 1 repetition maximum (1RM).
• Electromyography (EMG) was measured in the pectoralis major, deltoids (anterior and posterior), biceps brachii, triceps brachii, and external obliques.
• A randomized order of conditions was used after a familiarization session and 1RM assessment.

Main Results:

• The pectoralis major showed significantly lower EMG amplitude with stable loads compared to both swinging conditions.
• External oblique EMG amplitude was lower in the stable condition than the mediolateral swing, but not the anteroposterior swing.
• No significant differences in EMG amplitude were observed for the triceps brachii, biceps brachii, or deltoid muscles across the three conditions.

Conclusions:

• Bench pressing with swinging loads enhances pectoralis major and external oblique (mediolateral swing) activation compared to stable loads.
• Shoulder and arm muscle activation remains largely consistent across stable and swinging load conditions.
• Dynamic loading strategies in the bench press may offer benefits for specific muscle group recruitment.