Three-dimensional kinematics of the lumbar spine during treadmill walking at different speeds

The lumbar spines of primary importance in gait and its development is infl uenced by the upright posture adopted in human locomotion. However, little is known about the kinematic behavior of the lumbar spine during walking. T he aim of this study was to examine (1) lumbar spine kinematics during walk ing, (2) the effect of walking velocity on lumbar motion patterns and (3) t he coupling characteristics of rotation and bending. In 22 volunteers aged 15-57 years, the three-dimensional displacements of T12 to the sacrum were sampled during elementary movements of the trunk and during walking on a tr eadmill at four walking velocities. A three-dimensional electrogoniometer ( CA 6000 Spine Motion Analyzer) sampling at 100 Hz was used. We analyzed max imal primary and coupled motion ranges (ROM) and velocities in each plane. Lumbar ROM during walking did not exceed 40% of maximal active ROM. Transve rse plane ROM and frontal and transverse velocities increased with walking velocity. Coupling of rotation and bending during walking was individually variable and dependent on walking velocity. Moreover the smoothness of the bending-rotation path varied with walking velocity. A simplified envelope o f lumbar coupling characteristics during walking is presented, and the exis tence of an individually variable walking speed that is characterized by a more harmonic lumbar contribution is hypothesized.