The dumbbell hammer curl increases strength and size in the biceps and forearms. The neutral grip of the movement places more emphasis on the forearms.
Grab a set of dumbbells with a neutral grip so your palms are facing each other, and stand tall with your feet shoulder-width apart.
While bracing your core, curl the dumbbells all the way up to shoulder-height while keeping your palms facing each other. Pause at the top and squeeze your biceps, then lower the weights back down to the starting position.
Perform the movement with a controlled pace, not allowing momentum to contribute.
Do not allow the elbows to flare. Keep your elbows tight to your sides the entire time.
Do not hyperextend through the lower back. Brace you core and keep your spine flat throughout the entire movement.