3D spinal motion analysis during staircase walking using an ambulatory inertial and magnetic sensing system.

Previous research on spinal motion during walking has been restricted to the level walking condition in a gait lab although staircase walking (i.e., stair ascent and descent) exhibits unique biomechanical characteristics. A major difficulty in spinal motion capture during staircase walking is the in-the-lab limitation of measurement techniques. The purpose of this article is twofold: (i) to present an ambulatory spinal motion measurement system based on inertial and magnetic sensors (IMSs) to overcome this limitation and (ii) to demonstrate its application to 3D spinal motion analysis during staircase walking to fill a gap in the spinal kinematics literature. The proposed system is comprised of three tri-axial IMSs on the pelvis/spine measuring 3D angular motions of the pelvis, lumbar spine and thoracic spine and two uni-axial gyroscopes on the shanks providing gait cycle information. The proposed system was employed in comparing the spinal motion during the staircase walking to that of the level walking with respect to the motion pattern, variability, and range of motion (ROM). The test results showed clear differences in spinal motion between the level walking and staircase walking conditions, particularly in regards to the motion pattern and ROM of the flexion/extension and lateral bending of the spine.