Three-dimensional relationships between the movements of the pelvis and lumbar spine during normal gait

The three-dimensional motions of the pelvis and lumbar spine in walking wer e measured, in 20 normal adult males, using "Vicon" optoelectronic system, with reflective targets attached to lightweight rigs over the thoracolumbar junction and upper sacrum. Pelvic motion (using a room-based coordinate sy stem) corresponded to published data. In the sagittal plane, the change in lumber lordosis across the gait cycle was consistent within subjects, but v aried considerably between subjects. The phase relationships between pelvic tilt and lumbar lordosis also varied considerably between subjects. In the frontal plane, there was a much more consistent pattern of motion, spinal lateral bend generally following the pattern of pelvic obliquity, although there was some additional lateral bend, just prior to initial contact, supe rimposed on the generally linear relationship. The transverse plane showed similar waveforms between axial rotation of the pelvis and axial rotation o f the lumbar spine, except that motion of the pelvis was of greater magnitu de, and occurred later in the gait cycle than the motion of the lumbar spin e. Since arm swing could be expected to increase axial rotation of the spin e as a whole, this suggests that the thoracic spine undergoes greater motio n than the lumbar spine, in this plane. Comparisons between the present stu dy and two other published studies, using different methodology, showed onl y partial agreement. (C) 1999 Elsevier Science B.V. All rights reserved. Ps ycINFO classification: 2330.