Alternating supermans are ideal for strengthening the deeper muscles of the lumbar spine. The abdominal muscles are also heavily involved in stabilizing the core during this exercise.
At first glance, you would think this exercise is easy. In actuality, alternating supermans are somewhat difficult to perform; mainly because you have to balance using opposing limbs (e.g. right arm, left leg).
This exercise is most effective when performed slowly. Lie down on a workout ball. Position the ball on your abdomen. There should be four contact points touching the floor: both hands and both feet.
Slowly raise one arm to shoulder level. At the same time, raise and extend the opposite leg until it is parallel to the floor or slightly higher (Note: If your RIGHT ARM goes up, then your LEFT LEG should go up). Hold the position for approximately 5 to 10 seconds, then slowly lower your arm and leg. Repeat the same combination of movements [in alternating fashion] on the opposite arm and leg.
Position ball on stomach. Make four contact points with floor: both hands, both toes.
Slowly extend arm to shoulder height. At the same time, extend leg parallel to the floor. Hold for 5 to 10 seconds.
Lower the arm and leg. Repeat the movement on the opposite limbs in alternating fashion.