The PRE method was developed based on principles of weight lifters and body builders using free weights (barbells and dumbbells). Muscle strength is increased by slowly adding more weight and by increasing the number of repetitions.

There is specific isokinetic exercise equipment for strength training that isolates the back muscles. Most of these machines are available through a physical therapist.

Health clubs and fitness centers may offer benches and Roman chairs as another way to strengthen back muscles. But floor exercises, stability balls, and free weights are still the most economical exercise program for this type of strength training.

In addition to a strengthening program, many people also add lumbar stabilization exercises. Sometimes this is referred to as core training. With this type of exercise, low load, low intensity exercise is used. The exercises are often isometric. Isometric means that resistance is applied to the muscle but without moving any body parts. Many of the Pilates exercise programs available today focus on core training.

When just beginning an exercise program, it's always recommended that you have a medical exam first and get your physician's okay. Attending supervised classes at an exercise facility is a good way to get started.

If you have had a previous injury or are concerned about injuring yourself while doing an exercise program, then you may want to consider working with a physical therapist or athletic trainer. Safety is a concern. The goal is to strengthen the spine without causing a debilitating injury.