BY LINDA JOHNSON
05/16/2018| CANADIAN OCCUPATIONAL SAFETY
Most office workers spend long periods of time at a desk, seated in the same position for many hours every day. The health risks associated with prolonged sitting are made worse by poorly designed work stations that promote poor postures and lead to musculoskeletal disorders (MSDs) and repetitive strain injuries (RSIs). We look at some of the most common issues that office workers have and suggest what health and safety professionals can do to fix them.
Question: When I’m at work, I often get pain in my neck and shoulders. Why is that?
Answer: Most common ergonomic complaints — lower back pain, pain and discomfort in the arm, wrist, neck and shoulder and, less commonly, in the leg and knee — are caused by work stations that are improperly set up.
A proper set-up promotes a neutral posture (a comfortable posture in which the joints are aligned) and allows the body to be supported as much as possible to reduce muscle activity during the day, says Wayne Albert, dean of the faculty of kinesiology at the University of New Brunswick in Fredericton.
“Muscle is biological tissue and it will fatigue over the course of the day. And when it gets tired, that’s when injury is more prevalent.”
The problem is often height differential, he says. Ideally, a person who is five feet one inch tall should be seated at a desk that is about 24 inches high. For every additional three inches of worker height, the desk should be another inch higher. Thus, a person who is six feet tall should work at a desk that is 27 inches high.
Albert estimates 80 per cent of the calls he gets are from women who, generally shorter than men, have trouble with the standard desk height of 30 inches.
“They’re usually working at a work surface that is much too high. Therefore, their arms are elevated, their wrists are bent backwards and their neck has to extend to be able to read the screen.”
Often too, the chair doesn’t fit the worker. It may be an ergonomic chair, but if it is too large, the person’s back cannot engage with the back rest. All the mechanisms in the back rest designed to off load muscle activity are removed.
“So, as soon as you have to go into a non-neutral posture of your body, the muscles have to kick in. And when your muscles have to work all day, they get tired, they get sore and you end up with the pain,” Albert says.
Another important aspect of the chair is the seat pan, which may be too large or too short. If a seat is too small, workers tend to perch on the edge of the chair. If the seat is too large, it may catch the sitter in the back of the knees, compressing the nerves and blood flow, which may also cause the worker to perch forward on the edge of the chair. The chair then becomes a stool, and the worker will get no advantage from the backrest, whose purpose is to support the back muscles while the person is sitting. Moreover, on a chair that’s too large, the arm rests will not be where the worker’s arms are naturally placed. The worker will sit between the rests and not receive the support that off-loads the arms and shoulders.
Q: I spend many hours a day at my monitor and often end up with pain in my hand, wrist or forearm. What can I do about it?
A: The height of the work station is part of the cause of discomfort here, too. But another reason for hand and wrist pain is how the worker uses the mouse. Instead of moving the wrist back and forth when moving the mouse, the worker should use the forearm, keep the hand straight and pivot from the elbow. The hand should be in neutral (in line with the forearm), and the forearm should be parallel with the floor. The worker should not extend the wrist so that it is bent sideways, in an upward position or in a downward, flexed position.
Q: When I sit back in my chair, my feet don’t touch the floor. Is this normal?
A: When a work station is properly set up, the worker’s feet should be flat on the floor. In some cases, a short person may have the chair raised to accommodate the height of the desk but, consequently, his feet do not touch the floor. In such a situation, it’s important to provide a foot rest to support the feet, says Gary Friesen, ergonomic consultant at Friesen Ergonomics in Edmonton.
Q: How do I set up an ergonomically correct work station?
A: The surest way to achieve the proper ergonomic set-up is to provide customized desks, each one being the right height for the particular worker, Albert says. A less expensive option is to shorten the desk legs to the appropriate height. In about 90 per cent of the organizations he has dealt with, Albert says the preferred solution is simply to cut the desk legs down. Later, if the desk is given to a taller person, a safety manager can raise the desk up by placing blocks of wood under the legs. It’s also possible to buy pre-formed blocks or cups made of rigid plastic that can be placed under the desk legs to raise the desktop.
“It’s like creating an adjustable desk without having to buy a new desk,” Albert says.
When purchasing new equipment, look for adjustability, he adds. Adjusting desks and chairs is the easiest way to fix ergonomic problems.
“The more adjustable any equipment is, the easier it is to accommodate a large percentage of your workforce.”
To set up the chair properly, Friesen says, start by making sure the worker’s back is well supported by the lumbar support provided by the backrest. Adjust the chair height so the feet are comfortably flat on the floor. Find the correct height of the monitor: It should be at arm’s length and the upper portion of the screen should be at eye level. The keyboard or keyboard tray should be level with the forearm, hand and wrist so that the worker’s neutral posture can be maintained.
“The (factors) all fit together. If you change one, you have to look at the others as well,” Friesen says.
It’s generally helpful, he adds, to have someone trained in ergonomics check out the work station after it is set up. Moreover, workers should know how to adjust their work station and understand, too, they have the right to move their station around if they’re uncomfortable.
A good quality ergonomic chair is very important to support the lower back, says Diana De Carvalho, assistant professor of medicine at Memorial University of Newfoundland in St. John’s, N.L. It should be adjustable and provide good lumbar support and have arm rests that adjust properly. Try to choose a chair made with good quality foam.
“Foam degrades over time. You can spend a lot of money on something and it may not last as long. And as it breaks down, it may not be healthy to sit in.”
Also keep in mind, she says, task determines posture, so it’s important workers have the right chair for what they need to do. For example, a person working in a lab needs an ergonomic chair designed for someone working at a desk height that is higher than usual. There is no perfect chair suitable for all employees.
“People are individuals. Making an investment in furniture is important, but there isn’t a perfect chair that you can buy,” she says.
Moreover, De Carvalho cautions against relying too much on the chair.
“There is a concern a person may think, ‘I have this Cadillac chair. I can sit in it forever and I’m not going to hurt myself.’ But holding any posture for a long time, even if it is the best posture, is still not good,” she says. “So having a good ergonomic chair could be misleading. We need to move. We can’t sit for eight hours.”
Q: What do I do about glare on my computer screen?
A: Glare on a monitor can cause eye strain and symptoms including headaches and blurred vision. While most new screens have anti-glare properties and are better at reducing reflected light, glare remains a problem for many workers.
Part of the solution lies in proper placement of the monitor in relation to light sources, Albert says. Make sure there is no window either right behind or right in front of the screen. Ideally, the desk should be perpendicular to a window, rather than parallel to it. Tilting the screen is also helpful.
“If you have the screen straight up, you get more glare on it. So it’s important that your screen is tilted backwards at a 15-degree angle. That’s the natural accommodation for your eye,” he says. “Then, it’s easier for you to move from either the print that is on your desk or your keyboard to your monitor with only moving your eyes and not having to move your neck.”
Safety managers and workers can reduce glare with blinds or curtains, a screen glare filter or task lighting that will not reflect onto the screen.
Q: I want a stand-up desk. Can I have one?
A: Both prolonged sitting and standing can cause health problems, De Carvalho says. In addition to causing back pain and neck and shoulder strain, too much sitting also increases the risk of heart disease, diabetes and obesity. Just a few hours of standing can cause lower back pain and can lead to serious health effects, such as cardiovascular problems and varicose veins, over time.
Current research suggests a 3:1 ratio for the rotation of standing and sitting: for every three hours spent standing, they need to sit for one hour, De Carvalho adds. The adjustable standing work station — a work station that allows a user to perform the same tasks from either a seated or a standing posture — reduces sedentary time, does not reduce productivity and can help workers get the proper balance of sitting and standing.
“With an adjustable station, the worker can change it up, so they can sit when they need. But they also have the ability to stand to have a different posture. It’s getting that movement, which is really important. I think the best thing employers can do for their employees is to create a workplace that is as adjustable as possible,” she says.
Standing work stations also have drawbacks. First among these, of course, is expense. An electric, height-adjustable L-shaped work station can cost $2,000 to $3,000. It may be difficult, too, for an employer to buy a station for one employee and not for another.
Another disadvantage is that workers must adjust them properly, both for when they are standing and sitting, Albert says. When workers are standing, the desk must be set up properly so they are working at the right height and the right vision level for their standing height. Moreover, he adds, many standing desks don’t go down far enough.
“The lowest they often go is about 27 or 28 inches, while some shorter employees need a desk height of about 25 inches. So when you buy a sit-stand desk, you have to make sure it goes low enough.”
Standing work stations are expensive but they are a worthwhile investment, De Carvalho says, adding that research makes a good business case for them.
“The ‘active work station’ — one designed to give workers more flexibility to change their work postures during the day, allowing standing pauses, different seating arrangements and such — is good for workers’ bodies,” she says. “It’s also good for their minds, especially if they do creative work.”
Sometimes, Friesen says, a doctor will actually recommend to an employer that a particular worker receive a standing station due to a lower or upper back pathology if the worker has been treated by a doctor for a medical problem. In such a situation, the benefit of purchasing a standing work station for an employee is clear.
“For those with a medical back pathology, a sit-stand work station can make a big difference. It can mean that that individual can continue working, as opposed to taking medical leave. It could be costly to the employer with lost-time and a WCB claim. So there is a pretty strong business case to get one for that employee.”
However, companies often do decide, usually due to cost, not to provide standing desks for their employees. In breaking the news to staff, managers may want to point to other ways the company can help them get some of the same benefits that a standing station would have offered. Showing some attentiveness to workers’ well-being can help maintain staff morale.
First, Friesen says, the employer can encourage workers to look for opportunities to alternate between sitting, standing and walking. This improves blood circulation, provides rest for various muscle groups and allows changes in pressure points associated with sitting.
Workers should take regular breaks, walk around, and find ways to be active, such as walking to a colleague’s desk rather than sending an email. They may be able to redesign their tasks to allow for greater alternation between a sedentary and standing position. They should also be encouraged to take stretching breaks throughout the day for the upper extremity.
In lieu of standing stations, Friesen adds, employers could provide workers with really good adjustable ergonomic chairs that will fit them properly.
“That is a way that an employer can possibly convey that message to the staff, and most staff can understand that. If there’s a very poor ergonomic chair, that’s where an employer should be looking. That may pacify a lot of employees regarding not being provided with sit-stand work stations.”
The goal of ergonomics is to match the work to the person, so the worker is comfortable and muscle stress is relieved. Workers should be encouraged to report any discomfort they feel to a supervisor or health and safety representative, who may be able to help set up an ergonomic work station. It is also important for employers to listen to employees and be receptive to their needs, De Carvalho says.
“The right chair can go a long way to keeping an employee healthy and productive.”
Linda Johnson is a Toronto-based freelance journalist who has been writing for COS for seven years.
This article originally appeared in the April/May 2018 issue of COS.