Effects of box features on spine loading during warehouse order selecting.

Low back disorders in distribution centres or warehouses have been identified as an area of elevated risk in many industries. The task of an order selector requires workers manually to lift boxes from storage bins to a mobile pallet. This study explored the effect of box features and box location when lifting from a pallet in a storage bin upon spine loading. Ten experienced warehouse workers were asked to lift boxes from a pallet while the size, weight, handle features and location of the box on a pallet were changed. An EMG-assisted model was employed to assess spine compression, lateral shear and anterior-posterior shear during the lifts. The position from which the worker lifted a box on a pallet had the most profound effect on spine loading while the lower level of the pallet represented the greatest loadings on the spine. Box weight did not appear to be a feasible means of controlling spine loading unless its position on the pallet could also be controlled. The inclusion of handles had an effect similar to reducing the box weight by 4.5 kg, whereas box size did not effectively affect spine loading. The mechanisms by which these factors affect spine loading are discussed.