Kneel with the ball in front of you and lean over it. Place your hands on the floor and move forward until the front of your hips is resting on the ball. Squeeze your hips and raise both legs off the floor as high as you can, squeezing the back muscles at the top of the movement. Slowly lower. Do not swing or jerk at any point. Use good muscle control.

Do 12 reps, rest and repeat.

Part III -- Resistance Tube workout