Abstract: In the method, a predetermined group of demands, including demands that have associated parameters, are used, in respect of a shift of a job, in a process wherein, in respect of demands (i) that lack associated parameters, the amount of time that a worker, in the course of the shift, performs each demand, is derived; and (ii) that have associated parameters, each time such a demand is performed in the course of the shift, the duration, and associated parameters, is derived. The loads placed upon the muscles of the worker in the shift are calculated using, for each demand performed that is of the type that: (i) lacks associated parameters, the determined demand time and a predetermined group of load factors associated with said demand; and (ii) has associated parameters, the determined demand time, a predetermined group of load factors associated with said demand and said parameters.