Biceps curls and hammer curls are both effective exercises for building arm muscles.
Biceps curls target the biceps brachii muscle, while hammer curls work the brachialis and brachioradialis muscles.
Biceps curls are typically performed with a supinated grip, while hammer curls are performed with a neutral grip.
Hammer curls may be better for overall arm strength and size, as they work multiple muscles at once.
Biceps curls may be better for isolating the biceps muscle and achieving a peak contraction.
Both exercises can be performed with dumbbells, barbells, or cables.
Ultimately, the best exercise for building arm muscles depends on individual goals and preferences.