Biomechanical Stresses From Manual Load Lifting: A Static vs Dynamic Evaluation

Abstract

Abstract Over the last ten years, several static biomechanical models have been developed to predict the strength capability of a population and to quantitatively identify physical acts required in highly stressful jobs. In applying static biomechanical models to a dynamic act, such as lifting, it is assumed that the effects of acceleration and momentum are negligible. A detailed dynamic biomechanical simulation of lifting psychophysically determined maximum loads showed that the compressive force at the low-back and peak task moments at various body joints were approximately two to three times greater than those based on a static biomechanical simulation. Compressive forces at the lumbosacral joint, estimated from the static biomechanical simulation, were within the “action limit,” while those forces estimated from the dynamic biomechanical simulation exceeded the “maximum permissible limit.” However, the predictions based on static biomechanical simulation were in general agreement with the psychophysic...