“Sit up straight.” “Monitor at eye level.” “Hips and knees at 90 degrees.” These are just a few of the common and conventional mantras of office ergonomics that have been around for decades, basically since computers replaced typewriters. However, times and current thinking regarding office ergonomics has changed. No longer is one specific posture/position the only correct one but holding tight to the “conventional wisdom” may be detrimental to the health and productivity of the office worker.
There are misunderstandings in regards to office layout and posture that are quite old but still persist. There are several reasons for this including:
· We’ve heard, read or seen it for years
· Everyone we know seems to think and say the same thing
· It makes sense—at least we think it does
· We’ve seen it in an website, ad or marketing presentation for an ergo related gadget
Unfortunately, not all websites, authors, product designers and medical professionals keep up with all of the latest developments and research. This has led to the continued perpetuation of the conventional wisdom.
One thing to note about current office ergonomics thinking is that movement and different postures are encouraged and that there is no exact “best posture”. In fact your best posture is your NEXT posture! Our bodies are not made to maintain the same posture for hours on end. Our bodies are made to move which is why it’s important to build the ability to change posture into the office workstation. I’ll address this more later, but first I want to debunk some of the most common myths of office ergonomics.
Monitor at eye level
We’ve all heard that our monitor should be at eye level, meaning that the top of the screen should be at eye level. In fact, what I usually see when walking by offices are monitors that are higher than eye level. This position may be fine some people but for many it will be the wrong position. The current thinking for monitor height is for it to be a bit below eye level. To understand why this is the case, think about how you read a book or a newspaper. Where do you hold it? Is it at eye level? No, it’s lower. We tend to hold the book below eye level and angled away from us (top of book is farther away than bottom of book). Why do we hold it that way? One reason is that our arms would quickly tire if we held it up at eye level. However, the primary reason we do this is because it is far easier for us, our eyes and neck, to view and read things that are below eye level.
(To experience this, hold a book up in front of your eyes and read a few lines, then drop the book to your normal reading height and read a few lines. You should feel your eyes and neck relax when the book is brought to your normal reading height.)
Current thinking takes into account what we know is true for reading a book applies it to the height and angle of the monitor. The top of the screen should be below eye level and the monitor should be angled similarly.
Sit up straight with hips and knees at 90 degree angles
We’ve been told by our parents to sit up straight so this must be true and correct for sitting all day in your office chair, correct? Yes and no. Sitting upright with hips and knees at 90 degrees isn’t exactly wrong; however, it isn’t necessarily comfortable or ergonomic. There is more and more research that supports the idea of a wider hip angle. The “optimum” angle is around 130 degrees. The reason for this is that when the hips are at this angle the vertebrae of the lumbar spine are aligned in a manner that lowers the pressure on the spine. In addition, a somewhat reclined position is favored over sitting upright. When the body is slightly reclined the backrest of the chair is holding up the body weight. This causes the back muscles to work less and the spine to support less weight; therefore, minimizing fatigue and muscle tightness.
For the knees to be at 90 degrees means that the chair height has to be such that the feet reach the floor comfortably. The 90 degree knee angle isn’t a harmful position; however it isn’t “proper” ergonomics. The legs should not stay in a fixed position. The chair should be low enough to allow for different feet and leg positions (legs extended).
NOTE: If the chair height is good for the feet but the height of the keyboard is fixed and above elbow height then it becomes necessary to make changes. Either a keyboard tray needs to be utilized in order to bring the keyboard/mouse to the correct height or the chair height needs to be adjusted upward and a footrest utilized. Both of these options have caveats that must be considered before deciding which one is best.
This brings me to the last of the conventional wisdoms that I will address in this article which is…
Keyboard height should be at elbow height (elbows at 90 degrees)
While this conventional wisdom may again be ok for some people, variation from this height/angle is needed for most in the lower than elbow height (greater than 90 degree angle) direction. Having the keyboard/mouse positioned lower than elbow height (elbows between 100-120 degrees) allows for greater relaxation of the shoulders and less tension along the ulnar nerve (the “funny bone” nerve). When the keyboard is positioned below the elbows the angle of the keyboard itself should be keep flat or be put in a negative tilt (away from you) position. The negative tilt is easily accomplished for most modern keyboard tray designs today.
The final point to consider is that there is no exact posture that is perfect for everyone. Early on I mentioned that the best posture is your NEXT posture. It is important that employees have workstations with equipment, chair and accessories that allow them to move and alter their positions during the day. It is equally important to train them on how to adjust their equipment, the importance of movement and ergonomics so they are able to alter their positions to ones that add to their comfort, performance and to avoid injury.
What about standing?
I couldn’t conclude this article without mentioning the latest “craze” within office ergonomics—Standing. Standing at a workstation isn’t a craze since sit-to-stand desks have been around for several years. However, the research to support the need to reduce the daily amount of sitting has recently become available and the results are quite striking. Recent studies have indicated that prolonged sitting is detrimental to one’s health. In July, 2010 the American Cancer Society published a study in which they followed over 100,000 men and women from 1993-2006. The results showed that women who were inactive and sat over 6 hours per day were 94% more likely to die in the time period of the study than those who were active and sat less than 3 hours per day. Men who were inactive and sat over 6 hours per day were 43% more likely to die compared to their standing counterparts. (The findings were independent of physical activity levels, i.e. the negative effects of sitting were just as strong for those who exercised regularly.) In 2010 the University of Queensland Australia, School of Public Health reported “Even when adults meet physical activity guidelines, sitting for prolonged periods can compromise metabolic health” (http://www.medscape.com/Viewarticle/72534)
Besides the above research studies, standing promotes circulation, makes it easier to maintain neutral spine posture, and increases caloric expenditure. So, is it necessary for everyone to have a sit-to-stand workstation? No, however it is important to provide workstations that allow for workers to move and alter positions at their desk. Having adjustable equipment is only part of the equation. The other part is to have workers who know how to adjust their workstation to fit them. After all, what’s the purpose of having adjustable equipment if it’s never adjusted?
If the adjustable equipment isn’t adjustedEqually important is to provide training how to adjust their furniture/accessories, the importance of movement and good ergonomics so they are able to alter their positions to ones that add to their comfort and avoid injury.
Conclusion
There is much conventional wisdom that persists in office ergonomics despite research and evidence suggestion otherwise. It is important for those who work in offices and those overseeing office workers know and understand current thinking and how to apply it to their workstations and employees, respectively. The benefits of good office ergonomics to a company’s bottom line are many. They include comfortable and injury free workers which keeps workers compensation costs to a minimum; increased employee engagement and wellness; and greater employee productivity.
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