Investigation of a pork shoulder deboning operation.

An ergonomic investigation of force exertions during pork shoulder deboning was conducted. Nine male workers volunteered to participate in the study. Three cycles of the shoulder deboning task were measured for each worker, using an instrumented knife that provided direct measurements of grip forces and cutting moments applied to the knife. The average grip force values during the task were between 11 and 35% of the maximum voluntary grip force. A key finding was that there is high between-subject variation in exposure to integrated grip forces and cutting moments, which can have implications for exposure to risk for upper extremity musculoskeletal disorders. There was also high between-subject variation in cutting time. Measures of knife sharpness indicated that there is also variation in knife maintenance among workers during a 5-hour period. The implications of the results for training and further study are discussed.