Synergists: Anterior Deltoid, Biceps Brachii (short head only)
Mechanics: Isolation
Force: Push
Starting position
Sit on a stability ball with a dumbbell in one hand.
Roll downwards until your back is on the ball.
Raise the dumbbell over your chest while keeping your elbow slightly flexed and your shoulder rotated internally. Your elbow should point out to the side.
Execution
Keeping your elbow slightly flexed, inhale as your lower the dumbbell to your side in an arc-like motion until you feel a mild stretch in your chest or shoulder.
Exhale as you reverse the motion to return to the starting position.
Repeat for the desired number of repetitions.
Perform using the opposite arm.
Comments and tips
Compared to the incline one-arm dumbbell fly, this exercise forces activation of even more stabilizer muscles, especially in the core, since the stability ball is an unstable surface.
Internally rotating your shoulders will isolate the pectoralis major better.
Spreading your feet will help you balance better but will also decrease activation of your stabilizer muscles in the core.
