Dumbbell hammer curl on exercise ball

Sit on an exercise ball with your feet flat on the ground and your back straight. Hold a dumbbell in each hand with your palms facing your body and your arms fully extended. Keeping your upper arms stationary, exhale and curl the dumbbells while contracting your biceps. Continue to raise the dumbbells until your biceps are fully contracted and the dumbbells are at shoulder level. Hold the contracted position for a brief pause as you squeeze your biceps. Inhale and slowly begin to lower the dumbbells back to the starting position. Repeat for the desired number of repetitions.