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Applied Ergortomics 1987. 18.2, 146-152

lnvestigation oi optimal table height and surface angle in meatcutting

M. Magnusson* and R. Ortengren*

"Department of Orthopaedic Surgery t. Sahlgren Hospital, S- 413 45 Goteborg, Sweden. ^r Department of Industrial Ergonomio, Linkoping Imtitute of Technology. S-581 83 Linkoping. Sweden.

Butchers have a high frequency of occupational disordersor pain localised to their h3nds. shoulders, Iow back and neck, compared with other occupational groups. It is likely that the disorders are caused by high loadings of these parts of the body during work. The high loadings have been found to be caused by high resistance when cutting. inappropriate working postures and by manuał handling of materiał.

To improve the butchers'working conditions by providing means for appropriate working postures, cutting tables with adjustable height and surface angle were constructed and tested. Evaluations were madę during work in the laboratory and in the industry. The aim of these tests was to find the optimal height of the table for each butcher and to find out if a tilted surface would improve the working postures and be accepted by the butchers. The evaluations were madę by biomechanical calculations from photos, ergonomie analysis of videotapes taken during the tests and by using ranking scales.

The results show that (1) one optimal height of the table was not to be found, meaning a height resulting in a posturę that causes no load on both back and shoulders at the same time; (2) a table height of 17 to 22 cm below elbow height-reśulted in Iow loadings on both the Iow back and the shoulders and was ranked as the most comfortable height;

(3) tilting of the surface 5° to 10° was accepted by the butchers and ergonomically favourab(e; (4) the possibility of altering the table height during the workday was perceived as unloading sińce the load could be shifted between different parts of the body.

Keywords: Working ponura, butchers. musculoskełetal system

fntroduction

Butchers* working conditions have been of great interest lately in Scandinavia. Butchering is hard and slrenuous work performed in cold rooms; it is risky and demands great skill. The workload is illustrated by the fact that many butchers develop disorders or pain in their muscles and joints at an early age, thal all butchers are men. and that few remain butchers after 40 to 50 years of age.

Butchers who are cutting meat have a high frequency of occupational disorders compared with other occupational groups (Ronquist and Hansson, 1979; Jonsson and OuchterlonyJonsson. 1980; Viikari-Jumura,1983). The disorders are nuinly localised to their Iow back. shoulders and neck. These body parts are also subjected to high loadings during work which are mainly caused by factors such as inappropriate working postures. heavy materiaJs handling and high knife forers due to the cutting resistance of the meat (Magnusson et al. 1981, 1987).

Cutting meat is done either with the meat hanging on hooks or lying on a table. A great deal of the cutting and trimming is actually done at (ables, particularly when cutting pork.

At many places sevcra] butchers of various heights are working at a large common table, meaning that the table is either loo high or too Iow for each one working there. The shorter butchers often adjust the table height by standing on a platform. However. the use of it obviously incrcases the risk of stumbling and slipping accidents. Even at work-ptaces where the butchers have a table of their own, it is often difticult to adjust the table to a proper height because the adjustment ts tedious and usually requires help and tools from the maintenance department. Thus. the height of the tables will be a compromise to suit some of the butchers but will be too high or too Iow for others.

Working at a table that is too Iow requires a forward bent posturę, meaning inereased load on the back; when Ihe arms

146 Applied Ergonomics Jurtę 1937

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