Variety As the Spice of Work

Several studies point to a strong preference among workers for postural variation.

• By Jerry Laws
• Apr 01, 2005

Editor's note: Static postures aren't harmless; they can cause low back pain, varicose veins, and other problems. Sit to stand postures are preferable, says Ann Hall (amhall@linak-us.com), marketing manager for LINAK U.S. Inc. LINAK, a Scandinavian company with its North and South American headquarters located in Louisville, Ky., provides movement by electric actuation for customers who design and manufacture a multitude of finished products, including sit-stand desks. Hall discussed postural variation and adjustable workstations in a March 9, 2005, conversation with Occupational Health & Safety's editor that is excerpted here. References used in this article can be found in LINAK's booklet, Ergonomics at Work, which is available at www.deskline.linak.com/press/?id2=227.

Why is systematic postural variation preferable to sitting or standing?

Ann Hall: Holding one position where very little movement occurs (static posture) is a risk factor for ergonomic injuries that can lead to worker's compensation claims and time away from work.

From the management perspective, sit to stand is preferable because it decreases the risk of injury and thus the risk of costs. Additionally, sit to stand variation can boost productivity by reducing the length and quantity of worker breaks, decrease absenteeism, and delay the onset of muscle fatigue that typically occurs by the end of the work day. From the worker's perspective, sit to stand is preferable because it gives added flexibility, comfort, and helps protect them from injury.

From a medical point of view, why is postural variation preferable?

Hall: Sitting still in an upright unsupported position places 70 percent more static loading on the upper body than standing does.⁵

Prolonged sitting has been associated with discomfort of the back, lower extremities, neck, and shoulder. Reports of varicose veins, stiff necks, and numbness in the legs are more common among seated employees than among those doing heavier tasks. Effects of prolonged standing include swelling of the legs, sore feet, varicose veins, static muscle fatigue, and low back pain.⁵

Minor postural changes typically do not provide the adequate break to relieve the fatigued muscles. Alternating between sitting and standing postures gives enough postural change to allow specific body parts to rest. This helps reduce the impact and alter the load experienced by body parts throughout the day.3 Movement is important to keep the spine healthy, improve circulation, and reduce muscle fatigue.¹

What evidence do we have that workers prefer variation?

Hall: Several studies point to a strong preference for postural variation. In a study done out of Cornell University, there was a strong preference of 82.4 percent for using electric height adjustable workstations (EHAW). Over 81 percent of participants reported standing one or more times a day to work, and 18 percent reported standing five or more times.²⁴

These results are further supported by a 70 percent preferred posture rating from a Curtin University study and an 82 percent positive rating from subjects participating in a Miami of Ohio University study. Subjects in the Miami study also acknowledged they would stand in the future if their equipment adjusted to standup height.^3,6

Some excerpts from Cornell participants really tell the story:
* 'As soon as I started to get any pain I adjusted the table height and the pain either went away or got better. This is very necessary for working long hours.'
* 'I find that standing 3 to 4 times a day helps my neck and back. . . . This helps me to stretch and move while continuing with my work.'
* 'With this table my sitting and working posture felt good. Before, I would start wriggling in the afternoon--I stopped squirming in my chair with this adjustable height workstation.'
* 'I like the sit-stand configuration since it gives me the flexibility of standing up while typing. Also, it is easier for 2 people working and typing at the same time.'

The small amount of users who do not prefer postural variation can still benefit from a sit-stand desk because they can adjust the desk to the precise height that works best for their body dimension. This is a huge benefit in itself that can help eliminate awkward postures--another risk factor.

Can we extrapolate from the studies done up to now to the overall working U.S. population, both in the service sector and the manufacturing sector?

Hall: Study participants included bank tellers, IT engineers, and call center employees. However, anyone working for more than four hours in a fixed posture can probably relate to the participants. The job title and sector aren't the focus. It is the posture and discomfort that is the common thread. Over our lifetimes, eight out of 10 people will experience a back injury and back pain. In fact, low back pain is second only to upper respiratory infection as a cause for absence from work.⁴

For the office environment, traditional routine breaks from prolonged sitting, such as retrieving files and inter-office communicating, are now routinely performed at the automated workstation, which results in less daily movement. A large percentage of employees describe themselves as sitting for hours immersed in the monitor, many in one basic posture.⁶ For the manufacturing environment, lean practices have pushed up productivity levels. The average worker is expected to do more with less time. More often this includes working in fixed postures without much postural variation.

In what industries is variation widely practiced? In which ones would it do the most good?

Hall: The initial implementation of sit-stand desks began in data entry, call/dispatch centers, and manufacturing environments. Basically, multi-shift, multi-task, repetitive environments where there was a high incidence of worker's compensation claims.

In the last two years, however, we have seen widespread growth in a multitude of environments: IT, finance, health care, insurance, and educational markets. This goes back to what we talked about before: Anyone who is sitting or standing in a fixed posture for more than four hours a day can benefit. If you are unsure if sit-stand desks are a fit for your company, your best bet is to call your furniture dealer. Many will let you have one for a trial period.

How expensive are these adjustable products? Will employers recoup these costs--and how quickly?

Hall: An average cost for an electric adjustable desk is $1,500. Just like any other desk, there are models that run much less than this and also much more, based on the style and quantities purchased.

Companies spend hundreds of dollars on maintenance and spare parts for machinery, yet when it comes to employees, one of the most important production factors, they are hesitant to invest in ergonomic equipment and programs. This requires a change in mindset. An employee is a million-dollar asset with a 30-year lifespan. You have to ask yourself, 'What am I doing to protect my investment?' Prevention is much less costly than treatment.⁴ According to OSHA, an effective safety and health program can save $4 to $6 for every $1 invested.

If the sit-stand desk is for a new facility, you have to subtract the cost of a standard desk from the cost of a sit-stand desk to see how much the extra investment is going to cost. In this case, the payback period is usually very quick. Since you have no past data to work from, however, it is harder to calculate a tangible answer.

Sauer & Sauer, ergonomic experts out of Germany, use days of absenteeism due to illness to calculate the amortization of a sit-stand workplace, with the average payback being four days.

A calculation we are currently working with is based on productivity gain. This is much easier for the manufacturing sector. If you know that you are gaining extra minutes a day from a decrease in work breaks or two extra claims are being processed, you can take this information and calculate a payback. Variables include daily pay rate (salary plus benefits divided by days worked in a year), productivity gain (minutes gained divided by minutes worked in a day), and cost savings per day (daily pay rate times productivity gain).

Payback is cost of equipment divided by cost savings per day times days worked in a year. For example, a person whose salary and benefits equal $46,000 and works 240 days (reflecting two weeks of vacation and two weeks of holidays) can be 15 minutes more productive a day. The payback on a $1,500 workstation is 1.04 years.

How can employers encourage their workers to vary their postures throughout the work day?

Hall: One, buy them a desk that allows them to easily switch from sitting to standing. If that is not possible, encourage more work breaks or tasks that involve a significant postural change.

Two, provide training and ongoing communication to support your program. Like any piece of ergonomic equipment, it is not truly ergonomic unless it is being used as intended. This not only includes the 'how to,' but the 'why' and the 'what's in it for me,' as well. Positive results seem to further the likelihood that the work routine will be modified.

This article appeared in the April 2005 issue of Occupational Health & Safety.

This article originally appeared in the April 2005 issue of Occupational Health & Safety.