Starting Position: Sit on a stability ball with both feet firmly placed on the floor, hip-width apart or wider. Hold a dumbbell with both hands wrapped around the dumbbell handle. Brace your abdominal/core muscles to stabilize the spine. Pull your shoulder blades down and back. Do not allow your back to arch. Your head should be aligned with your spine. Maintain these engagements throughout the exercise.
Upward Phase: Exhale. Slowly press the dumbbell overhead. Straighten your elbows until your arms are vertical to the floor. Your elbows are pointing forward; straight but not locked. The dumbbell should be positioned directly over your head with your palms facing upwards and the dumbbell hanging vertically from your palms. Maintain your balance. Do not change the position of your head, torso, upper arms, wrists or feet. Keep your feet pressed into the floor and abdominals engaged to maintain stability throughout the entire exercise.
Downward Phase: Inhale. Bend your elbows in a slow and controlled manner, lowering the dumbbell behind your head. Do not allow the upper arms to move. Continue to bend the elbows to a 90 degree bend or until your upper arms begin to move backward. Do not make contact with the back of your head. Do not change the position of your head, torso, upper arms, wrists or feet. Slowly straighten the elbows and return to start position. Repeat.
Attempt to keep your upper arms vertical to the floor throughout the exercise and keep your elbows shoulder-width apart. Avoid arching in your low back as you extend your elbows overhead.