Team Doctors, Treatment and Training Center

American Fitness Quarterly, April 1989  

Injury Prevention of the Lumbar Spine During Strength Training Cycles

by James Stoxen, D.C.

     It has been estimated that 80%of athletes suffer from lower back pain over the course of their sports careers. Most lower back pain has a strong relationship to posture. It is well known that poor posture is a result of muscular imbalance. In this article we will attempt analyze posture by way of a simple plumb line to determine which muscles may be weak or in an imbalance state. I will also explain how this imbalance musculature of poor posture can cause lower back pain during training cycles and sports competition.

     Ideal posture, analyzed form the side or sagittal plane, has been determined as the perfect distribution of weight about the center of gravity in which the agonist and antagonist muscles are in perfect balance with respect to flexibility and strength. Perfect muscular balance in relation to posture will provide for optimum efficiency during movement of sports and your daily activity. This perfect balance is difficult to achieve.

Most athletes who suffer from lower back pain have a degree of hyperlordosis or excessive curvature of the lower spine. This excessive curvature is most commonly due to a forward tilting of the pelvis. This forward tilting of the pelvis will cause a jamming of the joints of the lower spine. The joints which are jammed are the facet joints and the discs. Discs are the shock absorbers, which lie between the vertebral bones. The posture of a forward tilting pelvis causes an increase in the effective curve of the spine. When you combine that with the stress from weight training, jumping or pounding the forces of running, there is a greater possibility of the nucleus which, is between the vertebrae to bulge. The disc usually will bulge at the weakest point which just happens to be in the vicinity of the nerve or sciatica. Leading to symptoms of pain or numbness and tingling in the leg. Sometimes the disc will bulge but not press the nerve. This is still a problem and there will certainly be pain and a future of degeneration within the weakened segment. Chronic degeneration will commonly result due to the daily microtraumatic stress of years of training with poor posture.

The posture of the athlete with the lower back pain can be evaluated visually by a plumb line (a line of string hung at the side of the body). Figure 1 represents good posture in relation to the plumb line. Figure 2 represents the most common representation of an athlete's posture who suffers from frequents bouts of lower back pain. As you can see there is a forward tilting pelvis and the increase in the lumbar curve. This poor posture is due to an imbalance of strength in the muscles of the trunk area.

There are certain rules of thumb to follow when analyzing posture:
1. The stronger muscle is usually the shorter muscle if not properly stretched
2. The shorter muscle exerts a torquing of the joints so therefore exerts a compressive force on the joints.
3.  The shorter muscle is usually less flexible if not properly stretched.
4.  Imbalance in stretching can lead to posture change.

In the figure of poor posture, we see that the abdominal and hamstring muscle groups are weaker with respect to the lower back, iliopsoas (hip flexors see Figures 3a and 3b) and the quadriceps group. We also commonly see an imbalance between the flexibility of the hamstring (which is commonly over stretched) to the quadriceps, iliopsoas, and lower back (commonly under stretched). These imbalances lead to a higher probability of lower back pain due to the effect on pelvic tilt phenomenon and the resultant excessive curve in the lower back.

Another way of analyzing the lumbar curve is to stand with the hells, buttocks, shoulders and head against the wall and attempt to press the lower back to the wall. One should be able to achieve this goal with little effort. This movement can also be used as an exercise to help reduce the lumbar curve. It can be done in the car, in class, at work, at home, or in the gym. See Figure 3c.

      The abdominal muscle group consists of the rectus abdominis, internal and

Continuation needed