Spinal and Pelvic Movement during Walking—A New Method of Study

Abstract

A non-invasive method of measuring pelvic and lumbar spinal movement during walking has been developed. Targets attached to the subject reflect light from stroboscopic lamps mounted near to each of three television cameras which are interfaced to a computer. The targets' locations are identified by the interface and stored as coordinate pairs. From the two-dimensional data from two cameras, three-dimensional data are derived and the relative movements of the lumbar spine and pelvis can be calculated. The ranges of spinal and pelvic movements in a group of twenty-two normal males have been measured. The mean values of spinal motion were 5.1° in the sagittal plane, 9.3° in the coronal plane and 8.3° axial rotation. The corresponding pelvic movements were 4.0° in the sagittal plane, 7.7° in the coronal plane and 11.2° axial rotation. The system is useful to document abnormalities and to record the effects of treatment.