Keep the weight in place throughout the exercise. Dont move it forward/back.
Start with a light weight and increase with experience.
Instructions
Set up for the weighted exercise ball sit up by getting an exercise ball and something to rest your feet against. This could be a wall, or as shown in the video a flat bench placed at 90 degrees.
Get the desired weight plate and sit on the exercise ball.
Place your feet under, or up against, your support.
Hold the weight above your head. Keep it close to your head.
Slowly lower yourself down until your shoulder blades start to touch the exercise ball.
Pause, then raise yourself back to the starting position.