Supine Computer Workstation

Image of a woman using a tilted computer workstation.

Project Team

Project Director: Scott Haynes
Previous Research Assistants: Caroline Kelly, Karen Williams, Edo Eussen, Young Mi Choi

Summary / Outcome Goals

Many people who suffer from chronic low back pain can not sit upright for long periods of time without pain. Lying on one's back can help to relieve this low back pain. However, most computer workstations can not be used when lying down. The goal of this project is to (1) measure the impact of different postures on user comfort and on the performance of basic computer-related tasks such as typing, using a pointing device, reading, etc. and (2) develop a computer workstation that will allow the user to access the computer from several working postures. The RERC is currently seeking collaborators interested in developing a computer workstation based on findings from this research.

Progress to Date

• Researched existing alternative computer workstations to identify current market for products that help people to access computers from a reclined or supine position. The research included products currently available on the market as well as custom designed solutions.
• Researched the various causes of chronic or recurring low back pain (LBP). Used information from previous RERC efforts as well as current journal-based literature and text books to identify common causes and treatment methods for addressing issues of chronic LBP.
• Used existing power wheelchair technology to construct an adjustable computer workstation test fixture. A tilt and recline wheelchair seating system was modified with computer keyboard, monitor, and pointing devices as well as additional support structures, to allow computer access from a variety of working postures.
• Completed testing of the first cohort of subjects in which each subject performed a variety of tasks from five different working postures. The working postures ranged from upright sitting to lying supine. Keyboard and monitor locations for each participant were based on the typical ergonomic arrangement for an upright seated posture.
• Completed improvements to the supine test fixture based on feedback from participants. Improvements included the replacement of the back and headrest with a single, extended back rest curved to provide additional support to the shoulders and upper back when in the supine posture.
• Completed testing of the second cohort of subjects using the improved test fixture. Second phase of testing also included an exit survey designed to collect quantitative opinion-based responses from participants regarding the features of the supine workstation test fixture.
• Modified the test fixture to improve upper extremity support. Increased the adjustability of the upper arm support and provided a width adjustment for the armrests.
• Completed testing of the third cohort of subjects, in which adjustments were made to optimize the position of the keyboard, monitor, and arm supports for each posture.

Key Findings

• LBP is the most common work-related disability in people under 45 years of age.
• It is estimated that more than one out of every two people (59%) will experience an episode of debilitating LBP in their lifetime. (Frank, 2002)
• The cost to the US economy due to issues of LBP is estimated to be $50-$100 Billion annually. (CDC, 1990)
• There are four main types of computer workstations developed to accommodate people working from a significantly reclined or supine position. They are: Laptray, Boom Support, Crossbar Support, and Integrated Chair designs. Results of this product search were published in Technology and Disability, 19(1), 41-52 (see below).
• Results of the typing performance and user comfort test revealed that inadequate support of the upper extremities while in supine postures leads to decreased comfort, which can impact typing speed. These results were published in International Journal of Industrial Ergonomics, 38(1), 35-46 (see below).
• Comments from participants indicate that the preferred position of the monitor and keyboard, relative to the user, might be different for different postures. For example, during the test, the keyboard was attached to the chair such that its position relative to the upper body would be consistent for all postures. This was done to focus on the impact of body posture and to maintain a consistent view angle with respect to the keyboard. Several participants noted that they would prefer to have had the keyboard lower in some of the supine postures. This would improve upper extremity comfort but would reduce visibility for operators that need to see the keyboard periodically while typing.
• Results from the test in which computer and support components were optimized for comfort and performance indicate that participants preferred the tilted or reclined postures, when component locations were optimized. The results from this study were published in International Journal of Industrial Ergonomics 39(5), 719-727 (see below).

Selected Publications / Presentations

• Haynes, S., (2009). “Effects of Positioning Optimization in an Alternative Computer Workstation for People with and without Low Back Pain.” International Journal of Industrial Ergonomics 39(5), 719-727.
• Haynes, S., Williams, K. (2008). “Impact of Seating Posture on User Comfort and Typing Performance for People with Chronic Low Back Pain” International Journal of Industrial Ergonomics, 38(1), 35-46.
• Haynes, S., (2008). “Working Posture Preferences for Elderly Computer Operators with Low Back Pain.” In W. Mann (Ed.), Aging, Disability and Independence: Selected Papers from the 4th International Conference on Aging, Disability and Independence pp. 151-159. Gainesville, FL; University of Florida.
• Haynes, S., Williams, K. (2007). “Product Review of Alternative Computer Workstations and Possible Workplace Accommodations for People with Chronic Low Back Pain. Technology and Disability, 19(1), 41-52.
• Haynes, S., Grubbs, R.L., Endicott, S., Williams, K., Williams, M. (2006, October). “Using A Wheelchair Seating System To Measure Postural Effects On User Comfort And Typing Performance.&rdquo Proceedings for the Human Factors and Ergonomics Society conference, San Francisco , CA.
• Haynes, S., Grubbs, R.L., Endicott, S., Williams, K., Williams, M. (2006, June). “Impact of Working Posture on Comfort and Typing Performance.&rdquo Proceedings for the Rehabilitation Engineering Society of North America Conference, Atlanta , GA.
• Haynes, S. (2005, June). “Product Review of Reclining or Supine Computer Workstations.&rdquo Proceedings for the Rehabilitation Engineering Society of North America Conference, Atlanta , GA.
• Haynes, S., & Williams, K. (2005, January 22). "Computer Workstations to Accommodation Low Back Pain." Presentation at the Assistive Technology Industry Association, Orlando , FL.
• Williams, K.L. and Haynes, S (2005, June). "Investigation of Low Back Pain Causes and Postural Relief in the Workplace." Proceedings for the Rehabilitation Engineering Society of North America Conference, Atlanta , GA.