Quantitative analysis of repetitive movement as a tool for diagnostic support in ergonomics

Abstract

Objective: To evaluate muscular strain in the upper limbs of workers in a freeze-processing plant for poultry by developing a tool for quantitative analysis, yielding a final score, which can provide diagnostic support in legal proceedings. Methods: The Strain index proposed by Moore & Garg was used to quantify biomechanical aspects of muscular strain, evaluating the intensity and duration of effort, frequency of movement, position of wrist and hand, speed of activity and duration of the task per shift. The index was applied in three critical work-areas in a freezeprocessing plant for poultry where the activities of nine workers were analyzed. Results: Absenteeism caused by osteomuscular lesions and mental-health problems reaches 20%. The three work-areas studied are those where the birds’ throats are cut, where they are suspended on a conveyor-belt and, where they are wrapped. These areas were chosen because they have the highest rates of absenteeism and rotation of workers. The findings identified final scores between 12 and 27, when 7 or more means the maximum risk. Conclusion: Defensive strategies developed by workers can reduce biomechanical problems arising from high throughput rates, but are not enough by themselves to allow production to proceed without the occurrence of osteomuscular problems.