Why your hammer grip feels harder than palms-up curl
Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you curl with your palm facing inward (hammer grip), your forearm muscle (brachioradialis) works harder to bend your elbow, while your bicep doesn't change effort — your body just uses the forearm more to make up for the bicep's awkward angle.
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
Max 100Randomized Controlled Trials
Max 90Cohort Studies
Max 72Case-Control Studies
Max 58Cross-Sectional Studies
Max 44Case Reports & Case Series
Max 30Expert Opinion & Narrative Reviews
Max 526 / 44
Evidence Score
A snapshot of a population at a single point in time. Can identify correlations and prevalence, but cannot determine the direction of cause and effect.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you curl with your palm facing inward (hammer grip), your forearm muscle (brachioradialis) works harder to bend your elbow, while your bicep doesn't change effort — your body just uses the forearm more to make up for the bicep's awkward angle.
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
Max 100Randomized Controlled Trials
Max 90Cohort Studies
Max 72Case-Control Studies
Max 58Cross-Sectional Studies
Max 44Case Reports & Case Series
Max 30Expert Opinion & Narrative Reviews
Max 526 / 44
Evidence Score
A snapshot of a population at a single point in time. Can identify correlations and prevalence, but cannot determine the direction of cause and effect.
Publication
Authors
Kleiber T, Kunz L, Disselhorst-Klug C
Related Content
Claims (6)
The brachioradialis is preferentially activated during elbow flexion when the forearm is in a neutral (hammer) grip position compared to supinated (palms-up) grip.
Elbow flexion performed in a stretched position (e.g., incline or preacher curl) increases relative activation of the brachioradialis by limiting biceps mechanical advantage.
When your palm is down, your bicep can’t pull as well because its tendon gets twisted — so your body makes your other forearm muscle work harder to bend your elbow.
Your body switches which forearm muscle does most of the work when bending your elbow — your bicep stays steady, but your other muscle steps up when your palm is down.
When your palm faces down and you bend your elbow, your forearm muscle (brachioradialis) works harder than when your palm faces up or straight ahead — but your bicep works the same no matter how your hand is turned.