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llnhooking large pieces off thc conveyor a strenuous because of thc high !cvel of thc hook (Fig. 8). To carry out this task the arm must be stretched to its maximum. the neck bent backwards and thc butchcr has to stretch on his tocs to reach the hook. From this unstable and strenuous posturę the meat is liftcd ofT the hook and caught and carried to a table. These pieces wtigh as much as 70 kg.

Cutting at a table consists ofhighly repetilive movemcnts of the arm (Fig. 9). Powerful abductions and flcxions of the arm from the shoulderjoint are often performed with the arm liftcd 70—90°. The elbow is kept in a flcxed position and is statically łoaded as the movements are very smali. The hand is mainly loaded by static muscle work, holding the knife and working with a stiff wrist. The pieces handled on the table are smaller, espccially when cutting pork, but are morę numerous; the work speed is high and the movements are therefore repeated at a high freąuency.

When sorting the meat, one hand and forearm is loaded by frequently repeated movements sińce the łask is often accomplished by throwing the difTerent pieces into several boxes placed in front of and beside the butchcr (Fig. 10). Normally the throwing is done with thc same hand.

The tables at which butchers work can usually be adjusted in heiglit, but this adjustment is seldom utilised sińce the adjustment is tedious and often requires help and tools from the maintenance department. Sometimes several butchers of various heights are working at a large. common table, so that the table is either loo high or too Iow for each one working

Fig. 8 Unhooking of a large piece implies stretching of

the arm, extension of the neck and a hearyy bur den to carry

there. The shorter butchers often adjust the table height by standtng on a platform. The height of the platform b fuced at about 10 cm. The use of it obviously inereases the risk for stumbling or slipping accidents.

Sawing at a bandsaw is a task which implies unnecessarily high loads on the Iow back. The construction of the saw inhibits the butcher from gettingcloser to the work area

Fig. 9 Cutting at a table. The cutting is assodated with high dynamie loading of the shoulder musełes and repetitive and static loading of the muscles of the arm and hand

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Applied Ergonomics March 1937