Muscle Group: Biceps
You are going to do this exercise the same way you would do regular Dumbbell Curls – except you will not be twisting your wrist at any point during the movement.
Your palms face inward (towards your body) and are fixed throughout the movement. Hammer curls not only train your biceps but also place a great deal of stress on your forearms.
For a variation of this exercise, you can do a regular hammer curl on the concentric (positive) part of the movement – then at the top (peak contraction) twist your wrist so that your palm faces down towards the ground on the eccentric (negative) portion of the movement. This again will add even more stress on your forearms.
The Gift Phil Heath shows us how the exercise is performed below: