Reverse Hyper Extension

Lying over a swissball with your hips towards the front of the ball and your hands on the floor, lift both your legs up keeping your upper body balanced and quiet through the motion. Go to you natural range of motion, not going to far to fall over the ball or strain your back. Going super slow will increase the difficulty.

An advanced method is the keep the legs super straight as it will challenge your flexibility and put more stress on your back.