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Fig. 12 Lifting and carrying meat and boxes is frequent.

Manuał lifting of 75 kg ocajrs and one man may lift and carry 4000—6000 kg a day

at ail Tor long periods of timc. When thc arm is lifted above hcart level, thc circulatory conditions arc ncgalively influenced, which also decreases Ihc timc bcforc fatiguc occurs. Thus, thc position of the arm and thc resistancc of thc meat arc two factors that causc the high loading on the shouldcr. Also, thc numerous throwing of pieces when sorting is highly repetitive work causing high loads on one arm. The throwing is carried out by a rapid, powerful extension of thc hand and might contribute to the high frequency (40%) of disorders of thc elbow.

The transportation of meat in thc working room is to a great cxtcnt a manuał task. Lifting and carrying boxes and cases weighing up to 40 kg and above arc common tasks. At scYcral workplaccs each man lifted and carried morc than 4000 kg every day. When cutting beef and pork ai a tablc, throwing is a common way of disiribution of mcat and cleancd bones into boxes and containers. When cutting beef from a hanging carcass. the meat is carried to a labie for furlher division. The carrying is particularly stressful due lo the large weight of the pieces.

In many companies which we yisiled the use of buffers and thc flow of materia! between workstations were not very węd planned, leading to timc losąes and unnecessary work. There ts no doubt that an inereased use of mechanised eąuipment to transport the meat bolh lo and from the butchers* workpbcc should reduce the work load lo a large extent and incrcase the efTiciency.

The high loads on the Iow back arc causcd mainiy by thc working postures. Sixty fivc perccnt of thc butchers considcrcd the Iow back as highly loaded and 55% had low-back pain. When cutting hanging meat the cutting and the catching of the meat being cut off often took place at a Iow working height. This resulted in a morę or less forwardly bent posturę of the back and caused high loads on the spine. Lifting in a posturę of combined forward flexion and rotation was common.

Unfavourable working postures occurred during work at a table when the height was not propcrly adjusted. Only at one workplace did the butchers have a table of their own which could also be easily and rapidly adjusted in height.

At all other workplaces, several butchers of various heights worked at tables that were shared or at a table otherwise fixed in height. Those for whom the table was loo Iow had to work in a forwardly bent position which inereased the load on thc back, and those for whom the table was too high had to work with elctrated shoulders and arms which caused sustained static loading, especiaily on the shoulder muscles.

(t appears from our study that the workload on the butchers is unnecessarily high and that it can be the main reason for the large frequcncy of disorders among them. By reducing the workload, the incidence of ovcrload troubles would decrease and the possibilily for the butchers to carry out their work until their pcnsionable age would probably incrcase.

A desirable way of reducing the workload in a work* iniensive job like meat cutting is to introduce a machinę to do the heavy part of the job. Although cutting robois have been designed and tested in production, they are not yet able to handle meat of varying size and shape; thus other means must be attempted.

An inerease in temperaturę has been suggested. U has been found that a smali inerease in temperaturę is not sufficienl, however. In hot boning — i e, cutting the meat immediately after the slaughtering and before it has been refrigeraced — thc reststance of the meat is favourably reduccd (Romquist and Hansson, 1979),but the method dcmandsa particularly high hygienic standard and that the slaughtering and the cutting are organised together. Most meat cutting companies in Swcden have no slaughtering and many of them are quite smali and not likely to accept measures that lead to heavy invesiments.

Fortunately. the strain on the butchers is, to a large extent, caused by bad working postures which can be improved in fairly simple ways. including introducing improved equipment at the workplaccs. The equipment should be designed so that the butchers could work standing uprighl with their hands reaching from waist level to breast level.

Conclusions

By adjusiing the working height to the individual and to the task performed. the loads on both the back and the arms could be kept at much lower levcls. Tables should be

Applied Ergonomia March 1987    49

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