Instructions:

1. Sit on an exercise ball with your feet flat on the ground and your knees bent at a 90-degree angle.
2. Hold a dumbbell in one hand and position it at shoulder height, with your elbow bent and palm facing forward.
3. Slowly press the dumbbell upward until your arm is fully extended, while keeping your core engaged and maintaining balance on the exercise ball.
4. Pause for a moment at the top, then slowly lower the dumbbell back to the starting position.
5. Repeat for the desired number of repetitions, then switch to the other arm.