Three-dimensional quantification of human standing posture

Abstract

Accurate but simple and inexpensive assessment of human posture is a requirement of many clinicians, yet a system to do this task is not available. Thus the purposes of this study were to design and build a computerized system for the three-dimensional quantification of the human erect standing posture, to assess the reliability of the developed system, and to present parameters to quantify standing posture. Reflective markers were used to highlight 24 body landmarks of 20 male subjects. Each subject stood on a Kistler force plate while a computer captured images from three standard PAL video camera views and the ground reaction force. Three-dimensional photogrammetric techniques were used to recreate the three-dimensional coordinates of the subjects' landmarks and the location of the line of gravity was determined from the force-plate data. It was concluded that the developed three-dimensional videometric method was reliable and that very small deviations of spinal alignment and trunk rotation as well as leg and arm positions could be detected by the system. Furthermore, eight parameters derived from the landmark coordinates provided valid and reliable inter-day measures of posture.