09/09/2026
Hammer Curls (Dumbbells)
The target muscle is the brachioradialis (red). The brachialis and biceps brachii (pink) assist in elbow flexion when the hand is in midposition.
Common mistake: Flexing the shoulder while curling Flexing the shoulder will significantly reduce the rotational torque the dumbbell produces on the elbow joint.
Once the dumbbell is in a straight line above the elbow (perpendicular to the floor), there is no rotational force at all on the elbow, and the elbow flexor muscles are at rest.
If you want to decrease the load on the elbow flexor muscles in the final repetitions, then you can use this adaptation; on the other hand, if you want to load the elbow flexors all the way, then keep the elbows close to the body.
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