Holding a pair of dumbbells, sit on the preacher bench.
Keeping your elbows flexed and your palms facing each other (neutral or hammer grip), place the backs of your upper arms flat on the arm rest.
Execution
Inhale as you lower the dumbbells until your elbows are almost fully extended.
Exhale as you curl the dumbbells back up toward your shoulders.
Hold for a count of two at the top of the movement and squeeze your biceps.
Repeat.
Comments and tips
Only your forearms should move.
Adjust the seat so that you can position the whole of the backs of your upper arms flat on the arm rest, from your armpits to your elbows.
You can perform the dumbbell hammer preacher curl with one arm at a time or, as described, with both arms simultaneously. Alternate to add variation and get the benefits of both variations.
Your brachioradialis is the target and not your biceps brachii because the brachioradialis is the primary elbow flexor when you use a neutral grip. What’s more, when your elbow is positioned in front of your body, your biceps (especially the inner or short head) is put into a state of mechanical disadvantage (active insufficiency).