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v1
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assertion
Analysis v1
Strong Support

When you curl with your arms stretched out on a bench, your forearm muscle has to work harder than your biceps.

34
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Evidence from Studies

Supporting (2)

34

Community contributions welcome

34

Forearm rotation and elbow angle differentially modulate biceps brachii and brachioradialis muscle stiffness and EMG activity during low-load isometric contractions: a cross-sectional study in healthy individuals

Cross-Sectional Study
Human
2025 Jul 2

When you bend your elbow all the way back (like in a preacher curl), your biceps can’t push as hard, so your forearm muscle (brachioradialis) has to work harder — and this study proved it by measuring muscle activity at different angles.

26

Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position

Cross-Sectional Study
Human
2015

When your palm faces down during a bicep curl, your biceps can't pull as well, so your forearm muscle (brachioradialis) has to work harder — which is exactly what the study found.

Contradicting (0)

0

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No contradicting evidence found

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