This exercise is great for glute and hamstring strength and core stabilizers. Lay with your head, neck, and shoulders on the stability ball. Place your ankles under knees and make sure your knees are in line with your hips. Start with your hips "dropped" toward the floor, perform the exercise by lifting your hips toward the ceiling and squeeze your glutes until you come into a "table top" position. Make sure that the ball remains stable throughout the exercise.