Sit on an exercise bench with back support and hold dumbbells in front of you at upper chest level with your palms facing your body and your elbows bent. Raise the dumbbells as you rotate the palms of your hands until they are facing forward. Continue lifting the dumbbells until your arms are extended above you in straight arm position. After a second pause at the top, begin to lower the dumbbells to the original position by rotating the palms of your hands towards you.