RESUMO
This study proposes a form of analysis of the geometrical alterations of the back and the spine shapes during a treadmili walking. Skin surface markers are attached to the body in order to localize anatomical points; twenty-seven points along the line defined by the spinous processes and eight bilateral points on the back. Eight gait cycles are recorded by videocameras in a calibrated space to allow the three-dimensional reconstruction of the marker's location. For each analyzed instant a continuous curve is fitted to the data to represent the spine shape. The two-dimensional curvature in the frontal plane is computed and shown as function of the vertical coordinate. The alteration in the spine shape at different leveis is shown as a function of the gait cycie phase. The oscillations of the bilateral points around the vertical axis, as function of the gait cycie phase are shown. The ana@sis suggests the existence of a mechanical torsion of the trunk during the gait cycie. The proposed methodology permits a geometrical representation of the moving spine which is continuous in space and time together with Quantitative information on the movement of the back.