Factors Responsible for Lower Back Pain in Kendo Practitioners

[Purpose] Lower back pain is a characteristic of Kendo practitioners which is often encountered clinically. The present study was undertaken to analyze the features of the spinal alignment in Kendo practitioners and their relation to lower back pain. [Subjects and Methods] Of the 32 Kendo practitioners who consulted our hospital with a complaint of lower back pain and received physical therapy during the two years and three months from January 2005 to April 2007, On X-ray, the degree of eight kendo practitioners' spinal curvature was measured by Cobb's method. Inclination and rotation were measured at each intervertebral level of the lumbar spine. The angle of inclination at each intervertebral space (L1/2, L2/3, L3/4 and L4/5) was measured. In one of the kendo practitioners, the motion of stepping forward to make a frontal thrust was analyzed three-dimensionally. [Results] During the forward-stepping motion, the thoracic spine showed right convex curvature and the lumbar spine showed left convex curvature, with Cobb's angle being 12.4 ± 2.5 degrees for the thoracic spine and 13.7 ± 1.7 degrees for the lumbar spine. [Conclusions] These results suggest that shear stress at the left intervertebral joint at the L3/4 and L4/5 levels and stress of the facet joint capsule are involved in lower back pain.