The Facts
Health professionals throughout the world have agreed for many years there are definite benefits in alternating between sitting and standing throughout the working day however until recently Electric Sit Stand Desk technology has been cost prohibitive and therefore not used in the general workforce
Most fixed desks are set at a height of 720mm. This height is to ensure the user can fit their legs under the desk without hitting the underside of the desktop. In order to accommodate the tallest people 720mm was the agreed upon standard as it is a suitable height for the 90th percentile male. Therefore a standard fixed height desk is unsuitable for 90% of males and an even higher percentage of females.
The majority of height adjustable desks are actually Sit-Sit desks. Although the user can select their preferred desk height in a sitting position they are still susceptible to the musculoskeletal disorders that are associated with prolonged sitting. Many desks that pertain to be height adjustable are in fact “height selectable” This means the height of the desk can be altered to suit the individual but this must be done through mechanical adjustments that require specialised tools and skilled personnel.
Alternating between sitting and standing is promoted in the International Ergonomic Standard ISO9241 Part 5. “Specifications are derived from five guiding principles: versatility-flexibility; fit; postural change; user information; and maintainability-adaptability.”
Winkle and Oxenburgh (1990) determined the benefits of providing active breaks (standing /moving) versus passive rest breaks (sitting) from the point of view of maintaining the health of muscles and the spinal disc. They found that alternating between sitting and standing was the most effective way to maintain a productive workflow as the posterior wall of the inter-vertebral disc sustains cumulative degenerative changes when exposed to prolonged periods of high intra-discal pressure associated with flexed or semi-flexed seated postures.
Nerhood and Thomson (1994) studied the introduction of sit-stand workstations at United Parcel Service (UPS).Results showed workers averaged 3.6 adjustments to standing position per day and spent an average 23% of the time per day in a standing position. They found body discomfort decreased by an average of 62% and the occurrence of injuries and illnesses decreased by more than half.
Paul and Helander (1995) found office workers with sedentary jobs showed significant more spinal shrinkage throughout the day compared to those with less sedentary jobs. They also compared spinal shrinkage with office workers who stood in thirty minute sessions with those who stood for fifteen minute periods. When measured there was considerably less shrinkage in those standing for thirty minute intervals and workers with spinal disorders also showed a greater variability in the shrinkage pattern.
Marvin Dainoff at the Centre for Ergonomic Research, Miami University, assessed the effectiveness of standing through the day as a means of providing essential breaks. He did this by introducing adjustable equipment and asking the subjects to use this to help relieve fatigue. He then compared work breaks between the Standers and the Non-Standers and found “The Non-Standers took an average of 47% more work breaks...and the average duration of each work break was 56% longer than that of the Standers. There is strong evidence that intermittent standing increases productivity”
82% of the subjects had positive comments about standing in terms of providing relief and said they would stand in the future if supplied with adjustable equipment
Leon Straker and Andrea Roeloffs (2002) conducted a study at Bankwest in Perth to compare musculoskeletal discomfort amongst tellers in a “just sit” “just stand” or “sit/stand” position. The “sit/stand” posture required subjects to alternate between sitting and standing in 30 minute intervals. The study found “..evidence that postural variation is effective in reducing the experience of musculoskeletal discomfort for total body, back, lower limb and upper limb areas and that the duration for which a posture is maintained effects the experience of musculoskeletal discomfort..” Alternating between sitting and standing resulted in the least discomfort and was reported as the preferred posture by 70% of subjects with 20 % favouring sitting and 10% standing.
Alan Hedge (2004) “Effects of an Electric Height-Adjustable Worksurface on Self-Assessed Musculoskeletal Discomfort and Productivity in Computer Workers” compares participants experiences in two companies over a 4–6 week period when working at fixed-height work surfaces and then at an Electric Sit Stand Desk. “Participants answered a series of questions that asked about the severity of musculoskeletal discomfort(MSD) experienced over the previous 4 weeks period for various body regions....There were significant decreases in the prevalence of MSD symptoms..” 82% of participants reported an increase in productivity and indicated a preference for a height adjustable work surface and there was also a reported increase in the daily time spent standing versus sitting.
Drew Bossen (2007) in “Improved Workplace Performance and Productivity through Movement” notes “Micro-breaks have been shown to increase the body’s blood flow and reduce fatigue. The issue is that many work environments don’t have the flexibility to allow workers to leave their respective workstations each hour. Using Sit-Stand Workstations allow employees to take a break from their static seated postures without leaving their work area” He summarises his report as follows. ”Movement is part of the human experience and it should be encouraged in the workplace. The ability to move must be both accessible and sustainable to ensure desired outcomes. Electric Height-Adjustable Work Surfaces are the ideal solution”
References
J Winkle, M Oxenburgh “Towards optimizing physical activity activity in VDT/office work” Sauter, SL
H.L. Nerhood and S.W.Thompson “Adjustable Sit Stand Workstations in the Office, People andHarmony. Proceedings of the Human Factors and Ergonomic Society 38th Annual Meeting
R.D.Paul and M.G.Helander Effect of Sit-Stand Schedule onSpinal Shrinkage inVDT Operators, Designing for the Global Village Proceedings of the Human Factors and Ergonomic Society 39th Annual Meeting
Leon Straker, Andrea Roelofs. “The experience of musculoskeletal discomfort amongst bank tellers who just sit, just stand or sit and stand at work”; Curtin University of Technology: Perth, Western Australia
Dr. Marvin J. Dainoff. “The Effect of Ergonomic Worktools on Productivity In Today’s Automated Workstation Design”; Center for Ergonomic Research, Miami University: Oxford, Ohio
Professor Alan Hedge “Effects of Electric Height Adjustable Worksurface on Self-Assessed Musculoskeletal Discomfort and Productivity in Computer Workers” Cornell University, Design and Environmental Analysis
Drew Bossen” Improved Workplace Performance and Productivity through Movement” The Emerging Role of Adjustability. Atlas Ergonomics
