weighted overhead crunch (on stability ball)

Sit on a stability ball with your feet flat on the ground and your knees bent at a 90-degree angle.

Hold a weight plate or dumbbell with both hands and extend your arms overhead.

Engage your abs and slowly curl your torso forward, bringing your chest towards your knees.

Pause for a moment at the top, then slowly lower your torso back to the starting position.

Repeat for the desired number of repetitions.