Sit on a preacher bench with your feet flat on the floor, holding a dumbbell in each hand with an underhand grip (palms facing up), and your arms extended over the preacher bench pad.
Engage your core and curl both dumbbells towards your shoulders by bending your elbows, keeping your upper arms pressed against the pad.
Squeeze your biceps at the top of the movement, ensuring the dumbbells reach shoulder height.
Slowly lower the dumbbells back to the starting position, fully extending your arms. Repeat for the desired number of repetitions.
Form tips
Keep your upper arms stationary against the pad to isolate the biceps.
Keep your wrists straight and avoid letting them bend backward.
Exhale as you curl the dumbbells up and inhale as you lower them.