Step 1
Starting Position: Sit on a properly inflated stability ball (one that compresses approximately 6" under your body weight) holding dumbbells, with your feet flat on the floor. Slowly lean backwards while walking yourself out along the ball until your head, shoulders, and upper back make contact on the ball. Adjust your leg position to create a 90 degree bend at the knees with your thighs and torso at or nearly parallel to the floor. Your thighs should be hip-width apart with your feet facing forward and your weight distributed evenly through your feet.
Step 2
Depress and retract your scapulae (pull shoulders down and back) to make firm contact with the ball and maintain this position throughout the exercise. Grasp each dumbbell with a closed, pronated grip (thumbs wrapped around the handles, palms facing forward) and position them at, or just above chest level, aligned with your armpits. Maintain a neutral wrist position (straight, not bent).
Step 3
Upward Phase: Exhale, stiffen your torso by contracting your abdominal/core muscles ("bracing") to stabilize your spine and slowly press the dumbbells upward to a position directly above your chest with your elbows extended, but not locked. Your hands should be shoulder width-apart or closer, and wrists neutral (straight, not bent). Keep your feet pressed into the floor and your hips pushed up towards the ceiling to maintain stability and control during the exercise.
Step 4
Downward Phase: Inhale and slowly lower the dumbbells in unison until they lie level with or near your chest. Attempt to keep the dumbbells parallel with each other and wrists in neutral position (straight, not bent). Your head, shoulders and upper back should maintain contact with the ball, and your torso and thighs should be parallel with the floor.
During the upward phase, avoid the tendency to thrust your hips upwards and arch your back. Your torso and hips should remain rigid and parallel with the floor throughout the exercise.