Athletes and people in general injure lower back muscles (erector spinae) quite often. To prevent such injuries, lower back exercises such as prone back raises (Superman) and cross body lift (pointed dog) are often recommended. In addition, it is possible to find many individuals doing various forms of sit-ups to strengthen the lower back.
These commonly executed lower backexercises are assumed to be best. But are they? There is no questioning that the prone back raise and cross body lift exercises work the lower back muscles, but mainly in the isometric (static) regime. The dynamic work is done through approximately a 10 to 20° range of motion depending upon the persons strength and flexibility.
Because of this these lower back exercises are only partially effective. For a lower back exercise to be fully effective,, it should work the muscles through the full range of motion which is about 80 to 90°. In essence, the lower back muscles are involved in raising the trunk from about 45º forward spinal flexion to about 30-45º extension-hyperextension from the neutral, or what is considered to be the anatomical position.
The main purpose of these exercises is to help stabilize the spine in its neutral position. Thus they are of value if this is needed. However, for most actions in sports and every day movements that involve the lower back, dynamic lower back exercises are much more beneficial. Understand that they also improve stabilization of the spine.
The best exercise to work the lower back muscles dynamically through a full range of motion (from maximum flexion to maximum hyperextension against the pull of gravity) is the back raise. It is typically best performed on the on the Yessis Glute Ham Back Machine.
In this exercise you work the muscles against resistance through the full range of motion. This is why a Glute Ham Back machine is used for this exercise. It is the only apparatus that allows for the correct positioning and movements to take place. A 45º angle bench is not effective as it only works the muscles against resistance for a very short range of motion.
When executed correctly, the back raise is the only exercise strengthens the lower back muscles through the full range of motion. Studies have shown that when you do the back raise and develop sufficient strength of the erector spinae muscles, you rarely get any lower back problems, especially if you have good technique in the movements.
For those who do abdominal exercises to strengthen the back it should be understood that the abdominals are not structural support muscles. The abdominal muscles, when contracted strongly, create greater intra-abdominal pressure which helps to hold the spine in place. They are of some value in back health but do not strengthen the lower back muscles.
For more information on these and other exercises, see Biomechanics and Kinesiology of Exercise and Explosive Golf, which has a separate chapter devoted to the lower back strength.