PHYSICAL WORKLOAD OF LORRY DRIVERS - A COMPARISON OF 4 METHODS OF TRANSPORT

Four groups of eight lorry drivers, transporting goods on wheeled cage s, as packed goods, on pallets, or as bulk cargo, were studied during a complete working day. The drivers working with bulk cargo served as a reference group. Manual materials handling and the working postures were studied by observation. The heart rate (HR) was continuously reco rded and related to observed tasks. The relationship between HR and ox ygen uptake during a simulation of loading and unloading and the maxim al oxygen uptake (VO2 max) were measured in a laboratory for every dri ver. The lorry drivers worked long hours, only the group transporting wheeled cages worked less than 11 hd(-1) on average. Driving made up a lmost half of the total working time in all groups. In general, the hi ghest HR was found during loading and unloading. Loading and unloading of wheeled cages was done for 2 h d(-1), at 50% of VO2 max. The drive rs transporting packed goods and pallets loaded and unloaded for aroun d 100 min d(-1), at 48% and 35% of VO2 max respectively. When the driv ers of these two groups lifted, their trunks were flexed for more than 60% of the time. The most important difference between the reference group and the other groups was that the drivers of the former rarely p ushed or pulled anything. It is suggested that the required pushing an d pulling forces were largely responsible for the high physical worklo ad during loading and unloading.