Abstract A combined optimization and finite element approach was used to predict biomechanical parameters in the entire lumbar spine during static lifting. The resultant forces and moments during lifting at all lumbar levels were determined from free body diagrams, and were then partitioned to the trunk muscle fascicles and intervertebral discs using a nonlinear optimization algorithm, with the equilibrium at all lumbar joints satisfied simultaneously. A three-dimensional finite element model of the thoracolumbar spine under the application of the upper torso weight, lifted load, and forces in muscles was used to predict the intradiscal pressure, facet force etc. Different muscle force distribution patterns were found, compared with ones predicted from traditional optimization-based force models used at one spine level. No significant facet forces and restorative moments from the ligaments were predicted at all lumbar levels but the lumbosacral joint.
Kong et al. (Sun,) studied this question.