Effect of a desk attachment board on posture and muscle activity in women during computer work

Abstract

Working at a computer is part of a large number of jobs and has been associated with upper extremity musculoskeletal disorders and back pain. The study evaluated the effects of a board attachment on upper extremity and back. The findings are mixed in that the board may have a positive effect in preventing back pain, but may be detrimental to upper extremities. Effect of a desk attachment board on upper extremity and trunk posture, and muscle activity was assessed in women video display terminal users. Participants completed a standard 20-min computer task under two conditions: 1) using a standard desk; 2) using a desk attachment board designed to support the forearms. Bilateral electromyography of the trapezius, multifidus and longissimus muscles and the right anterior deltoid and forearm extensor muscles was recorded. 3-D trunk and upper extremity posture was monitored. Participants were tested before and after 2 weeks of familiarisation with the board in their workplace. Perceived tension and discomfort were recorded before and after use of the board. Use of the board tended to increase muscle activity in the right trapezius and forearm extensor and to decrease muscle activity in the back. Perceived tension in the low back decreased slightly with the board. The board may be useful in reducing tension in the low back during computer work, but may adversely affect the upper extremities.

Keywords:

• posture
• muscle activity
• computer work
• low back
• upper extremity

Acknowledgements

This project was funded by a research grant provided by the Workplace Safety and Insurance Board (Ontario). Special thanks to the HMRC at Queen's University; Leone Ploeg and Carolyn Heymans at the HMRC for their technical assistance throughout the project, Mike Agnew for writing LabView data collection programs, Amira Hussein for help with data collection and Syed Nagvi at the Occupational Health Centre for Ontario Workers for his ergonomics expertise. Seven Workplace Boards were lent to the authors by Metamorphosis Design and Development Inc.