[Assessment of stress on the spine using a biomechanical model in relation to time studies]

The loading of the lumbar spine in the working process can be judged by the loads to be raised or carried and the bending of the body, a biomechanical model serving as the basis of calculation. Up to now our knowledge on the length of work loading the body in the working process in insufficient, that's why statements on the amount of heavy labour causing harm to the body can scarcely be given. The results of detailed time studies done with welders and mechanics in the field of heavy mechanical engineering and the building of installations were: postures loading the lumbar spine were taken for less than 1 minute on average, in most cases up to 20 seconds, and altogether they had a share in the shift of 16% on average.