Sit on a stability ball with a dumbbell in one hand.
Roll down until your back is on the ball and your torso is parallel to the floor.
Raise the dumbbell vertically above your body and hold it using a neutral grip (palm facing the other side).
Inhale as you bend your elbow and lower the dumbbell to the side of your head.
Exhale as you straighten your elbow and push the dumbbell back to its original position.
Repeat for the prescribed number of repetitions.
Repeat on the opposite arm.
Comments and tips
The lying one-arm dumbbell triceps extension on a stability ball is a great exercise for developing unilateral upper body strength and enhancing stability.
Compared to the lying one-arm dumbbell triceps extension, this exercise is more challenging because the stability ball is an unstable surface. This forces greater activation of your core muscles to keep your torso stable while your elbow moves.
You can place your free hand just under the elbow of your loaded arm for support.
If there are strength imbalances between your arms, start with the weaker arm first. Do not perform more repetitions with your stronger arm.