The authors evaluated muscular strengths exerted by the forearm during driving of subway tunnels, grinding and polishing of metal products and riveting of airplane wings within the framework of a grant project using the method of integrated electromyog- raphy. The highest muscular strength exerted by the group of flexors and extensors were measured during riveting. In the listed activities the all-shift timeweigted averages were at the border of the limit for the predominantly static kind of work. The all-shift limits are maintained particularly due to the character and organization of work and especially due to the decreased work intensity related to a lower number of orders. Nevertheless in all the three types of work the 55 % Fmax limits were exceeded for short period of time. In the riveting of aircraft wings the limits were exceeded for almost the half of the effective time of working operation. In view of these observations the authors recommend modification of the criteria for evaluation of work overload exerted upon upper extremities in relation to frequency or time periods of muscular strengths exceeding 55 % Fmax limits as well as to the transfer of vibrations, which were also found to exceed the recommended limits during the most demanding work operations.

        Key words: driving subway tunnels, grinding, riveting, muscular strength, integrated electromyography, vibration