Dumbbell one arm pullover on exercise ball

Sit on an exercise ball with your feet flat on the ground and your knees bent at a 90-degree angle. Hold a dumbbell with one hand and extend your arm straight up above your chest. Slowly lower the dumbbell behind your head while keeping your arm straight. Pause for a moment, then raise the dumbbell back to the starting position. Repeat for the desired number of repetitions, then switch arms.