Three-dimensional force model of the low-back for simple computer programming.

A three-dimensional static model is described to evaluate the forces on low-back muscles and on the spine during manual handling tasks and other forceful activities. It is simple to use either with a calculator or programmed onto a micro-computer, whilst being more accurate than existing simple models. Comparisons are made with a more sophisticated model that requires mathematical libraries and programming skills. As predictions are similar, so is the area of validity: the proposed model's accuracy is good for light tasks but poorer for strenuous ones.