The Ergonomics of the “Seated Worker”: Comparison Between Postures Adopted in Conventional and Sit-Stand Chairs in Slaughterhouses

Abstract

This case study aims to compare conventional and sit-stand chairs regarding Brazilian Regulatory Standard 36 (NR-36) requirements. Two types of chairs present in a slaughterhouse in southern Brazil were compared (sitting and sit-stand posture). The seven NR-36 requirements of seat characteristics were used: (1) to have height adjustable to the worker’s height and the nature of the tasks performed; (2) little or no conformation at the base of the seat; (3) rounded front edge; (4) backrest adapted to the body for protection of the lumbar region; (5) easy-to-use adjustment systems; (6) constructed with material that prioritizes thermal comfort; and (7) footrest that adapts to the length of the worker’s legs in cases where the operator’s feet do not reach the floor. The sit-stand chair met 6 requirements of the NR-36, lacking the attribute that requires backrest (4), in contrast, the conventional chair met all requirements. The function of the backrest in the sitting posture is linked to the reduction of load on the spine. Although the sit-stand chair has no backrest, the posture adopted when using this chair is more natural and distributes 60% of the body weight in the lower limbs, resulting in less intervertebral disc compression. Based on this principle, the sit-stand posture may be an alternative to be tested in slaughterhouses. It was concluded that both conventional and sit-stand chairs met most of NR-36 requirements, being options for alternating postures.