Instructions:

1. Sit on an exercise ball with your feet flat on the ground and your back straight.
2. Hold a dumbbell in each hand with your palms facing forward and your arms fully extended.
3. Keeping your upper arms stationary, exhale and curl one dumbbell while rotating your forearm until your palm is facing your shoulder.
4. Inhale and slowly lower the dumbbell back to the starting position.
5. Repeat the curl with the other arm.
6. Continue alternating curls for the desired number of repetitions.