The higher action levels will not, however, lead to unequivocal actions to eliminate any risks to the operator. It must be strongly emphasized that, since the human body is a complex and adaptive system, simple methods cannot deal in simple ways with postural and loading effects on the body. What the RULA system d provides is a guide, and Y It was developed to drab boundaries around the more extreme situations. However. the conbination of factors which influence the load but varv between operators, and factors which alter the indLidua1s response to a particular load’, may contribute to increasing the load from being within acceptable boundaries to being a serious problem for some people.