With a dumbbell in one hand, stand behind a steeply inclined bench.
Supinate your loaded arm (rotate your palm so that it faces upward) and rest your arm on the surface of the bench, with your elbow almost fully extended.
Keeping your arm supinated, exhale as you curl the dumbbell to your shoulder.
Hold for a count of two and squeeze your biceps.
Inhale as you lower the dumbbell until your arm is almost fully extended.
Repeat for the desired number of repetitions.
Repeat the exercise with your opposite arm.
Comments and tips
Keep the back of your upper arm, from your armpit to your elbow, flat on the bench.
Do not allow the dumbbell to touch the bench.
The standing dumbbell preacher curl targets your brachialis, not your biceps brachii. The brachialis is the strongest flexor of your elbow. Part of it sits under your biceps brachii, while the rest sits on the side of your upper arm, between your biceps brachii and triceps brachii. As such, when you build your brachialis, you produce a bigger biceps peak (because the brachialis props up your biceps) and you increase the separation between your biceps brachii and triceps brachii.