SYMMETRY OF LUMBAR ROTATION AND LATERAL FLEXION RANGE OF MOTION AND ISOMETRIC STRENGTH IN SUBJECTS WITH AND WITHOUT LOW-BACK-PAIN

There is substantial reason to believe that asymmetry of trunk motion plays a significant role in the development and presentation of low back pain. However, there has been little review of objective measurements of low back pain and asymptomatic populations to support these assumptions or the related clinical models. In order to study asymmetry of trunk function and its relationship to the presence of low back pain and laterality of symptoms, 120 subjects with low back pain (LBP) and 168 subjects without low back pain (NLBP) were tested for rotation and lateral flexion, active range of motion (ROM), and isometric strength using the B-200 Lumbar Dynamometer. A similar pattern of asymmetry was found in both NLBP and LBP populations; however, the magnitude of ROM asymmetry was significantly greater for the LBP subjects (p < .005). There was also a positive relationship between ROM magnitude of asymmetry and intratest variance in LBP subjects that was not evident in NLBP subjects. No relationships were found between isometric strength measures and LBP nor between laterality of asymmetric function and laterality of radiating symptoms. The asymmetry observed in the LBP population may be an augmented expression of normal asymmetrical performance, and behavioral factors may play a role in this expression. These observations may influence our use of lumbar function asymmetry as an objective clinical sign relating to specific pathological processes.