Hammer curls are a strength training exercise that specifically targets the biceps and forearms. They are a variation of the traditional bicep curl, but with a neutral grip where the palms face each other during the full range of motion. Hammer curls target the long head of the bicep, as well as the brachialis and brachioradialis muscles in the upper arm and forearm. These muscles are responsible for bending the elbow and building forearm and grip strength. Hammer curls are an isolation movement, which means that they target just the bicep muscle. However, they also provide a small benefit for the triceps. The hammer curl is a simple exercise that beginners can quickly master, and it is a functional exercise that mimics natural movement patterns.