Here are some of the most important benefits of hammer curls : While the traditional bicep curl exercise targets your biceps brachii muscles, the hammer DB curl exercise through its rotating hand movement engages your forearms, elbows, and deltoids too. Dumbbell hammer curl is a great exercise to improve your grip strength. A popular variation of the dumbbell hammer curl is to lift the dumbbells with your palms facing straight out in front of you in the starting position. This is called an "offset grip" hammer curl . See the right way to do hammer curls , which muscles are targeted, and optimal variations. Animations included. Learn the proper form and technique of hammer curl, a variation of dumbbell curl that targets your biceps and brachialis. Find out the benefits, common mistakes, alternatives and variations of this exercise.