The medicine ball is a versatile fitness tool that can help you achieve numerous fitness goals, including increased flexibility, increased core strength, stability, heightened balance and lean muscle mass. Below are several exercises for lateral flexion with the stability ball. Lateral flexion works your body through abduction, which occurs when you move your body away from your middle. On a stability ball, this occurs by moving your spine to the left or to the right. Lateral flexion strengthens your obliques and quadratus lumborum.

Make sure you select the proper sized stability ball. You will want a ball that when you sit on the middle of the ball with your legs out in front of you, that your hips and knees both bend to a 90-degree angle. For beginners, look for a ball that is not fully inflated. This will help with stability and balance. When beginning with a medicine ball, you will want to select a ball between 1 to 3 pounds. More advanced lifters or individuals with significant core strength can select a ball between 4 to 6 pounds.

To begin this exercise, simply start by lying on your side across a stability ball with the ball under your hip. Your feet will be on the ground, stacked atop one another, providing balance for your body. Hold a medicine ball with both hands at chest level. Your body should be in a straight line with your ankles, knees, hips and shoulders stacked on top of one another.

Raise your upper body up towards the ceiling while keeping your lower body steady. Remember to keep your body parallel during this entire exercise. Repeat 12 times and then repeat on the other side.

Sit on a stability ball with your feet out in front of you, knees bent to 90-degrees. Hold the medicine ball with both hands directly over your head. Arms should be fully extended. In a slow motion, move the ball laterally over to the right, rotating slightly at your waist. Remember to keep your arms straight over your head. You should feel this motion in your left abdominal muscles. Return to the start and repeat on the left side. Do 10 complete repetitions.

This exercise is very similar to exercise #1 except that it changes how you hold the medicine ball. This change alters how your body will respond to this weighted load, causing your body to incorporate different muscles from exercise #1.

Begin by laying on your right side over the stability ball with your legs extended behind you supporting your body. The ball should be situated under your right hip. Hold a medicine ball over your head. Slowly bring the medicine ball up towards the ceiling by crunching the left side of your torso. Lie back down and repeat motion 10 times. Repeat on your left side.

Complete the above exercises with additional abdominal exercises to get a complete core workout. It is recommended that you complete 10 minutes of core exercise 2 to 3 times a week in addition to strength training and a cardiovascular routine.