Optimizing hypertrophic strength training: electromyographic effects of forearm position on biceps brachii activity

Optimizing hypertrophic strength training: electromyographic effects of forearm position on biceps brachii activity. Download PDF Abstract This study examined the acute effect of three forearm positions (supination, neutral, and pronation) on biceps brachii sEMG amplitude during a standardized hypertrophy-oriented resistance exercise. While the optimal forearm position for maximizing muscle engagement in dumbbell exercises remains debated, this research uses surface electromyography (sEMG) to provide practical insights for coaches, athletes, and rehabilitation specialists.

Fifty-six right-handed male participants with strength training experience performed elbow flexion exercises with dumbbells while biceps brachii activity was recorded using surface electrodes. Two predefined sequences with reversed order were used to reduce potential order and fatigue effects. SEMG analysis revealed significant differences in biceps brachii activation across forearm positions.

In pronation, right-arm EMG activity averaged 215 µV, increasing by 106 µV in neutral and an additional 100 µV in supination. On the left side, pronation resulted in 249 µV, rising by 188 µV in neutral and 93 µV in supination. Cohen’s dz effect sizes indicated moderate-to-large differences in recorded sEMG amplitude between forearm positions.

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