Association of low back load with low back pain during static standing.

BACKGROUND:Although poor standing posture is a known cause of low back pain, the mechanisms involved are unclear. The aim of this study was to clarify the kinetic and posture angle features of standing posture that might influence low back pain. METHODS:Sixty-seven young men were enrolled in this cross-sectional case-control study and were categorized according to whether they did or did not have low back pain. Habitual standing posture was assessed in each group, using a three-dimensional motion analysis system, force plates, and a spinal mouse. Kinetic and posture angle factors were compared between participants with and without low back pain. The relationship between specific features of standing posture and low back pain was analyzed using logistic regression. RESULTS:The intervertebral disc compressive force and the low back moment were significantly greater in the group with low back pain than in the group without low back pain. The intervertebral disc compressive force was the factor most strongly associated with low back pain during static standing. CONCLUSIONS:Logistic regression analysis identified intervertebral disc compressive force as an independent variable associated with low back pain. This finding suggests that increased intervertebral disc compressive force may promote development of low back pain in standing posture