I have been told my back pain is due to a bulging disc. It sure feels like the muscles are the real problem. Is there any way to tell which came first--the disc problem or the muscle imbalance?

Studies show that only 10 percent of back pain cases have a clear cause. That means 90 percent of chronic back pain has an unknown cause. CT scans, X-rays, and MRIs show defects in the spine when the patient doesn't even have any symptoms. On the other hand painful symptoms occur when nothing shows up on the imaging studies.

Many doctors and therapists think the muscles are a major part of the problem. This hasn’t been proven true yet. EMG studies have been used to measure the electrical activity of muscles during spinal movement.

EMG studies were recently used to compare the muscles of healthy subjects to people who have back pain. Researchers found that the muscles of back pain patients didn't fatigue as quickly as healthy subjects. This may be because patients with back pain hold back and don't use their back muscles with as much force as healthy subjects.

The more we can find out about muscle function, the better able we will be to find a rehab program for back pain that works.