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Evaluation of a sitting aid: The Back-Up

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Author: Vink, P. · Douwes, M. · Woensel, W. van
Source:Applied Ergonomics, 3, 25, 170-176
Identifier: 232617
doi: DOI:10.1016/0003-6870(94)90015-9
Keywords: Workplace · Back load · Back support · Electromyography · Musculoskeletal disorders · Office work · VDU work · Computer terminals · Computer workstations · Evaluation · Human rehabilitation equipment · Musculoskeletal system · Occupational risks · Personnel · Testing · Musculoskeletal disorders · Posture · Sitting aid · Ergonomics · Adult · Back · Body posture · Chair · Controlled study · Functional assessment · Human · Human experiment · Image display · Male · Neck · Normal human · Occupational accident · Office worker · Sitting


The effects of a portable back support, the Back-Up, were tested in 28 variables. Both subjective and objective physical load measures were recorded during sitting with and without Back-Up, most of them during VDU work. The main result was that the posture of the upper back and neck/head was improved by the Back-Up. However, the knee straps induced unacceptable high pressure and increased significantly the discomfort in the legs. Based on these results the Back-Up was modified: the contact area between the strap and the knee was enlarged. This modified Back-Up was tested again for 13 variables with 10 new subjects. The knee pressure turned out to be acceptable and the discomfort was equal to sitting without the Back-Up. Based on this research the Back-Up is considered as a possible addition to more fundamental ergonomic improvements such as adjustable furniture and variation between sitting, standing and walking tasks, especially for improvement of the neck load. However, the Back-Up should not replace proper ergonomic workstation and work organization design or a backrest on the chair. Furthermore, the Back-Up should not be made obligatory, and it should be worn only for a part of the day, because it limits variation in postures.