EFFECT OF WORK REST SCHEDULE ON PERCEIVED DISCOMFORT SCORE AND THERMALTHRESHOLD SHIFT OF OPERATORS USING HAND-HELD VIBRATING MACHINES

摘要

Time-integrated fatigue may lead to different types ofinjuries during the operation of a machine (Muller, 1953;Folkard and Monk, 1985; Rosa, 1995; Christensen et al.,2000). Such fatigue stretched over a period of months andyears may cause physical, physiological andmusculoskeletal disorders (Waersted and Westgaard,1991). In many real working tasks in industrial settings, theperiods of intense physical activity alternate with restperiods or periods of lighter work. This maximizes the totalquantity of physical work an individual can perform duringthe working day, compared to working at a steady butlower level (Muller, 1953; Astrand, 1960). In such cases,the work is designed so that the overall energy expenditure,averaged over the working day and taking into accountboth work and rest, remains within acceptable limits.