Large Ball Exercises

A large exercise ball is a 75 cm size stability ball. A stability ball is an inflated ball used for core and balance training. The balls come in smaller sizes of 65 cm and smaller and one larger 85 cm size. The 75 cm ball is recommended for use by people taller than 6 feet 2 inches, according to "Ultimate Core Ball Workout" by Jeanine Detz. Sizes are somewhat arbitrary. When sitting on the correct size ball, your knees should make 90-degree angles with your feet flat on the floor.

Exercise Ball Abdominal Crunches

The abdominal crunch is a traditional exercise for the stomach muscles performed on an exercise ball. Doing the exercise on the ball is harder than doing the exercise on the floor because the floor won't move out from under you. Begin the exercise lying on an exercise ball with your back and shoulders touching the ball. Your knees are bent at right angles and your feet are placed hip-width apart on the floor. Extend your arms over your head with your upper arms next to your ears. Your hips are lifted as high as your knees. Then, round your back and raise your head and shoulders toward the ceiling. Bring your arms up with you so they stay next to your head. Finish the exercise by lowering back onto the ball.

Ball Reverse Plank

The reverse plank exercise on the ball uses your core, but emphasizes the muscles of your buttocks and lower back. This exercise is done positioned face up with your feet on the ball. Get into position by sitting on the ground and placing your calves on the ball with your legs straight. Your hands are put on the ground in line with your shoulders. The arms are straight. Then, lift your body until it makes a line parallel to the floor. Take three deep breaths. Next, lower your buttocks to touch the floor without taking your legs off the ball to complete one repetition. An intermediate version of this exercise is done by lowering your hips almost to the floor but not touching down between reps, as outlined in "Ultimate Core Ball Workout."

Double-Leg Stretch with Ball

The double-leg stretch is a full-body exercise that involves moving the arms, torso and legs while working your core. The double-leg stretch is a classical Pilates exercise modified for use with an exercise ball. The abs are engaged to keep your lower back flat as you move your body with your legs on an exercise ball. To start the exercise, lie on your back with your arms held in the air at your sides, palms in. Bend your knees and place the bottom of your feet on the ball. Your head and shoulder blades are raised off the floor. Squeeze your abs to push your lower back into the ground. From there, roll the ball forward and straighten your legs. Simultaneously, raise your arms up in an arch until your arms are in line with your ears. Return to the starting position next by bending your knees to roll the ball toward you again and also lowering your arms back to your sides. Detz recommends leaving your head and shoulders on the floor if you have difficulty keeping your back down.