Numerous mathematical models have been developed to investigate the high
incidence of low back pain associated with lifting activities. These mainly
consider the muscle forces required to support the spine, and few have
considered the additional role of curvature.
One previous model which represented the spine as an arch (Aspden 1987)
indicated the curvature to have a significant effect on both loading and
stability of the spine. However this model included collective loading
patterns for body weight and muscle forces, and only partial representation
of the spine. On the basis that the level of anatomic detail of a model affects
the accuracy of its predictions (McGill and Norman, 1987), this thesis
describes the development of a model which provides greater detail for
investigating spinal stability in the sagittal plane.
The curvature of the whole spine, a distributed loading pattern for body
weight, and the activity of individual spinal muscle groups have been
considered. Comparison with the previous arch model has shown these to be
necessary features for determining the loading and stability associated with a
given posture. In particular, application of individual muscle forces provide
greater control of stability at each vertebral level. By considering the force
requirements of the individual muscle groups and the consequent loads at
each intervertebral joint, possible areas of tissue over load can be identified.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.