Finite element model of a lumbar spinal motion segment to predict circadian variation in stature

Epidemiological studies suggest that repetitive lifting is of importance in the development of back injuries. In vitro studies suggest a direct link between repetitive loading and a variety of disc tissue failures but the efficacy of such studies is limited. For this reason, a non-linear finite element model including both solid and fluid components of the disc was developed. The finite element model was used to determine the pattern and the magnitude of disc height change with time over a 24-h period due to normal daily activity. The results agreed well with those observed in vivo.