Bench Press Upper-Body Muscle Activation Between Stable and Unstable Loads

Area of Science:

• Exercise Physiology
• Biomechanics
• Sports Science

Background:

• The bench press is a fundamental upper-body exercise with numerous variations.
• Research extensively covers unstable surfaces but lacks data on unstable loads (ULs).
• Understanding muscle activation differences between stable (SL) and unstable loads is crucial for training optimization.

Purpose of the Study:

• To investigate and compare muscle activation patterns during the bench press exercise under stable load (SL) versus unstable load (UL) conditions.
• To determine if load stability influences the recruitment of key upper body muscles.

Main Methods:

• Twenty resistance-trained men performed bench presses at 60% and 80% of their one-repetition maximum.
• Unstable loads were created using kettlebells suspended by elastic bands.
• Electromyographic (EMG) activity of five upper body muscles was recorded.

Main Results:

• All five measured muscles exhibited significantly greater activation at 80% compared to 60% intensity.
• Muscle activation was significantly higher during concentric compared to eccentric phases of the lift.
• No significant differences in muscle activation were observed between the unstable load (UL) and stable load (SL) conditions.

Conclusions:

• Upper body muscle activation during the bench press is not significantly different between unstable loads (ULs) and stable loads (SLs).
• Resistance training program design can incorporate either load type based on coach or athlete preference.
• Further research may explore other variables like joint stability or injury risk.