Bridge Plank On Ball
Kneel facing a ball, resting your elbows and forearms on the ball. Tighten your abs and lift upward into the Plank position so that your back and legs form a straight line and you are supported only on your elbows and feet. Hold for 20 seconds, keeping your abs and torso area tightened and stabilized, and repeat twice. Try to build up to 1 minute.
Advanced: Perform the plank on the ball as described, and once you are stabilized and secure, slowly lift your right leg in a straight line using your gluteal (buttock) muscles. Hold for 20 seconds and then change legs. Repeat twice with each leg.