By Katherine Salant
This is Part 2 of a two-part series. Go back to Part 1.
When you put together your home office in your new house, you'll need a good chair. This doesn't mean the extra one from the dining room or the one you've had since college. You owe it to yourself to get an ergonomically designed office chair with multiple adjustments for the arms, seat, back and tilt - features that have become widely available over the last 10 years.
Why a multiple-adjustment chair? It will help you maintain good posture and this is essential to avoid stress-related muscle injuries caused by hours at the keyboard, explained three experts in recent interviews - Terry Hirth Caldwell, a massage therapist in Ann Arbor, Mich., who has treated the sore muscles of office workers for 18 years; Bill Dowell, an ergonomist with the Herman Miller furniture company in Zeeland, Mich.; and Suzanne Bade, an occupational therapist at the University of Michigan.
What posture should you be striving for while working, and how can a chair help?
For computer-related office work, you don't have to sit ramrod straight like a soldier, Hirth said. This is OK for short periods, but do it all day, she cautioned, and you'll be unnecessarily fatigued. A better posture for the keyboard, and one that can be sustained all day, is a "neutral" position that puts your head, wrists and hands in the right place. This is easier to achieve in a multiple-adjustment chair that provides back and arm support exactly where you need it while allowing your upper back and upper arms to relax. Getting your head correctly positioned will be more beneficial than you might suspect, Hirth added. Most people tend to tilt their head forward toward the monitor, and the weight of your head - about the same as an 8-pound bowling ball - strains your neck and upper back muscles, making them chronically sore and tender.
A multiple-adjustment chair with a "synchronous tilt" has additional advantages, Dowell said. With this feature, the seat and back tilt together so that your spine forms an "S" shape instead of a "C" shaped curve with its characteristic slouch. The S shape is preferable because it relives pressure on the disks of your lower spine and your lower back muscles.
Bade pointed out the importance of adjustable arm supports. When your chair has them, it's easier to keep your forearms and wrists in the right place for keyboarding. Your arms should be bent at an angle of about 90 degrees or more so that you can type at the keyboard with your wrists extended straight, not cocked up or down. Another plus with the arm supports, you're not holding your arms up all day, so you'll be less tired, Bade said.
To fully grasp the benefits of a multiple-adjustment office chair, I arranged to test two in my own home office - a Mirra chair made by Herman Miller and a Think chair from Steelcase. I chose these two chairs because they have won numerous prestigious design awards and because the two companies that manufacture them are known for the ergonomic soundness of their designs.
Both test chairs are designed to accommodate about 90 percent of American adults, that is, anyone from 5 feet to 6 feet 2 inches, and 100 pounds to 250 pounds. To cover such a broad range of physiognomies, the arm rests on both chairs can be adjusted up or down about 6 inches; Mirra's also move in or out about 2 inches (this feature will be added to the Think chair, starting this summer). While in a seated position, you can adjust the seat height up or down about 6 inches, and the seat depth about 4 inches, which makes the seat bigger or smaller. You can vary the tilt by about 22 degrees, which allows you to change postures and tilt back while you are talking on the phone, or taking in the view outside. The seats are also big enough for you to wiggle around and comfortably change positions while you are at the keyboard.
In addition to the adjustments for your physical stature, you can also make adjustments for specific tasks - the arm rests on both chairs can also be adjusted for keyboarding or reading.
Although both the Mirra and the Think chairs have a similar degree of flexibility, they do not achieve it in the same way or feel the same - proof positive that you need to shop around and try out many chairs before you select one instead of ordering one from the Internet on the basis of a photograph, a mistake that many people make, Hirth said.
The Think chair, which feels like a soft mattress, has a series of stainless steel wires across the back that are individually cut and shaped to mimic the human spine. The chair conforms to your body and supports it, no matter how you sit. Rather like driving a car with an automatic transmission, you don't have to rearrange anything - in ergonomic terms the back support is "passive."
In contrast, the Mirra chair, which feels like a firm mattress, provides back support that is passive and active. As a result, the chair is more like driving a stick shift, which gives you a greater feel for the road and more control over performance. Specifically, the Mirra chair has a seatback made of molded plastic with holes that vary in size and shape to fit and support the contours of your back. This is combined with an adjustable bar that provides lumbar support exactly where you want it (the lumbar region is where the spine curves slightly inward). You can also fine tune the tension of the lumbar support to make it firmer. Both chairs have a synchronous tilt, but it is greater on the Mirra, which means that when the chair is properly adjusted, you feel buoyant.
Both chairs can be purchased from dealers for Herman Miller and Steelcase. Although both Web sites list "suggested retail prices," the retail furniture market is highly competitive and prices are highly discounted; Herman Miller said the cost of its Mirra chair, depending on the options selected, is about $530 to $700, and Steelcase said buyers of its Think chair should expect to pay about $450 to $800. This might seem pricey, but you are going to clock a lot of hours in your office chair if you work at home full time. The only piece of furniture that you'll be using more will be your bed.
The Greenguard Institute has certified both chairs as being low emitters of volatile organic compounds (VOCs). Both are recyclable (99 percent for Think, 96 percent for Mirra), and you can dismantle the Think chair with simple tools in about five minutes. Recycling and dismantling should not be an issue anytime soon, however. Herman Miller's warranty on the Mirra is 12 years, and Steelcase offers a lifetime warranty on the Think.
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