In this study scientists at the University of Ulm (Germany) compare EMG
(electromyographic) studies of low back muscles. They compared the patterns of muscle fatigue in two groups. One group (31 patients) had chronic low back pain. The second(control) group (31 subjects) was healthy and didn’t have back pain.
The two groups were matched by age, gender, and amount of body fat. These three factors affect EMG outcomes. All the back pain patients reported pain for more than two years of moderate intensity. MRIs showed the pain was caused by disc problems.
The electrical activity of four groups of back muscles was measured. Maximum strength was recorded after 3 trials. The results showed the patient group only had 60 percent of the flexion strength of the control group. Ninety percent (90 percent) of the control group also had stronger muscles in extension (pushing back). The group with back pain had less fatigue but this may be caused by pain and moving in a way to avoid pain.
The authors conclude that back muscles do play a role in back pain. Lower strength and less electric activity of the muscles in the patient group helps prove this. Having matched pairs in this study reduced any differences there might be in the two groups. The results of this study will help researchers find better ways to treat back pain.