The article describes the experience from assessing the load of the upper limbs during the horning operation, which is one of the more difficult manual manipulations. Several analytical methods were used to obtain complex analytical data. They were used to identify deficiencies in work activity causing loading of the upper limbs, which in the form of increased effort affect employees' work performance in the monitored work activity. The excessive workload of workers has a significant impact not only on the decline in performance but also on the development of difficulties caused by the cumulative effect of risk factors (work and work environment) and, last but not least, on the increase in accidents and occupational diseases. A comprehensive assessment of work activity based on various methods serves as a basis for ergonomic rationalization of work activity to reconcile the demands of work activity with operators' physical possibilities and abilities.