Lower Back Exercises On An Exercise Ball

The erector spinae muscle group consists of three muscles that span your back vertically on each side of your spine. They are the major trunk extensors and hyperextensors, and assist with lateral flexion and rotation to the left and right. Strengthening these muscles may help prevent lower-back pain, which up to 85 percent of people experience at some time during their lives, according to Susan Hall, author of "Basic Biomechanics." Perform exercises using an exercise ball, also called a stability ball, for an effective and relatively inexpensive way to strengthen your lower back.

Reverse Extensions

Reverse extensions strengthen the lower back through extension and flexion ranges of motion. The erector spinae muscles contract concentrically to facilitate the extension movement and eccentrically to control the speed of movement during the flexion phase of the exercise. Lie with your abdomen on top of an exercise ball with your hands on the floor on one side of the ball and your toes on the other. Keeping your hands on the floor, lift your legs in unison until they form a straight line with your torso. Slowly lower your feet back to the floor and repeat. Keep your legs straight and feet together throughout the movement. Start by lifting just one leg at a time if you have trouble keeping your balance.

Russian Twists

Russian twists strengthen the erector spinae muscles through repeated torso rotations to the left and right. The muscles on the left side of your spine produce rotation to the right and vice versa. Lie with your upper back and head resting on top of an exercise ball. Position your feet flat on the floor about shoulder-width apart with your knees bent. Extend your arms above your chest and press your palms together with your fingers pointed upward. Keeping your feet flat, twist to the left on top of the ball until your fingers are parallel to the floor. Turn back to the starting position and continue in the opposite direction, twisting to the right. Continue alternating sides for your desired number of repetitions. Have a partner hold the ball from behind to keep the ball from rolling. Hold a weighted object, such as a medicine ball, to increase the intensity of the exercise if desired.

Bridge

Like reverse extensions, the bridge exercise targets the lower-back muscles through extension and flexion ranges of motion. Lie on your back on the floor, with your lower legs and feet together and elevated on top of an exercise ball. Place your palms flat on the floor beside your hips. Lift your hips until your legs and torso form a straight diagonal line, with only your shoulder blades and head on the floor. Hold for five seconds and then lower back down. Perform three to five repetitions. Alternately, lift your legs 2 to 3 inches off the ball to increase the intensity of the exercise.