Instructions:

1. Sit on the stability ball with your feet flat on the ground and your knees bent at a 90-degree angle.
2. Place your hands behind your head with your elbows pointing outwards.
3. Engaging your abs, slowly curl your upper body forward, bringing your chest towards your knees.
4. Pause for a moment at the top, then slowly lower your upper body back to the starting position.
5. Repeat for the desired number of repetitions.