Sitting Up Straight Study a diagram that explains how to improve your posture at the keyboard to prevent repetitive strain injury.

By Anna Isgro
Special to washingtonpost.com

Do the letters on your monitor seem to be dancing a jig? Do your fingers tingle after a session at the keyboard? Do you have aches and pains in your wrists, neck, shoulders or back? If so, your computer job may be extracting a painful price.

According to a study by the National Institute of Occupational Safety and Health, 88 percent of those who work at computers three or more hours a day suffer from eye strain. And nearly two million American workers experience carpal tunnel syndrome, caused by repeated activities such as typing or mouse-clicking, with symptoms including wrist discomfort and weakness in the hand.

There are, however, ways to prevent and treat the hazards of high-tech jobs – but you must take action. "You can't ignore non-specific work discomfort," says Margit Bleecker, director of Baltimore's Center for Occupational and Environmental Neurology. "You need to stop and ask 'what's wrong here?'" Next step: Learn how to incorporate ergonomic techniques into your office routine, as well as into recreational activities such as sports and hobbies. In this Q&A, Bleecker offers specific advice on preventing computer-related syndromes.

Q: How common are computer-related symptoms in the workplace?

Margit Bleecker: When I am called into a workplace, I find that roughly 30 percent of the workers are symptomatic. The numbers vary depending on the way the jobs are structured. For example, some jobs may allow for diverse tasks so there are fewer problems. In other jobs, such as those driven by deadlines, you may find that 50 percent of the workers have some symptom of repetitive strain injuries. The workers are so driven to get the work done that they ignore discomfort and then end up with a problem. I hear a lot of complaints of pain in the upper extremities and the back. I see a lot of tendinitis, carpal tunnel syndrome and pain in the shoulder and neck area.

Bleecker: The most common mistake we see is that the keyboard tray is located too high. This leads you to elevate your shoulders and extend your wrists, placing stress on those areas. Also, keeping your hands on the keyboard in an action-ready position, even when you're not typing, places undue stress on the muscles in the forearm. Other common mistakes are poor typing techniques, such as striking keys too hard, having your wrists at an angle and your thumbs extended, or your fingers extended because of long finger nails.

Bleecker: Think of playing the piano with fingers curled and wrists in a straight line with the forearm. You shouldn't lean on the wrist rest while typing, only while resting, and then it should be with the thumbs pointed to the ceiling so that the forearms are not in a prone position.

The same arm position should be used with the mouse. It's important to keep the hand open and relaxed when using a mouse. When you are reading or thinking, take little breaks and stretch your hands. It's less taxing on your hands and wrists to take frequent mini-breaks than to type continuously for 50 minutes and then take a 5 to 10 minute rest, for example.

Bleecker: Place the monitor in a position that allows you to keep your head straight, rather than having to bend your neck. Adjust it so that when you look straight ahead, your horizontal gaze is from the first line of type to 30 degrees below it. Never have your neck extended – that's one of the guaranteed ways to get a sore neck.

If you wear bifocals, lower the monitor at least 5 to 6 inches below eye level, again keeping the neck neutral. Maintain a distance from the screen that allows you to see easily, without having to lean forward to read the screen.

Locate your copy in an area under the monitor or next to it, allowing your neck to remain neutral. Your eyes should move from text to screen without any neck involvement.

Bleecker: The color of the screen and characters is a big factor. It's usually better to have dark letters on a light background. Flicker and glare from windows or desk lights cause visual fatigue. Often people come to me asking, "Why do I have a constant headache?" They don't realize that they are squinting against a glare. Windows should have blinds, and they should be drawn, because looking into bright sunlight and then at a dark screen alters visual acuity.

Also, eye muscles focus on the same position for too long when working at the computer, so it's important to let the eyes unfocus occasionally. You can do this by looking as far into the distance as you possibly can.

The best lighting for reducing eye strain is normally between 200 and 500 lux, as measured by a light meter. But for hard-to-read copy, you may need a higher level, in which case you could use a task lamp that lights up a specific area rather than the entire room.

Bleecker: Your back should be straight and in contact with the chair. Your neck should be straight, your thighs parallel to the floor and your feet supported or planted on the floor. Remember to stand up every once in a while; pressure on the lower back area is greatly diminished in a standing position compared to sitting.

Bleecker: Comfort is paramount. Your back should feel adequately supported. The entire back must remain in contact with the chair to ensure good posture. Most people prefer a high-back chair. Take time to adjust your chair. The chair back should adjust for height and angle so that you get proper spinal alignment.

The seat pan should fit properly. The front part of the seat should slope down slightly and should not hit the back of the knee but rather allow a small gap between the leg and knee, thereby reducing pressure at the back of the thighs.

Armrests take the stress off the back and should be adjustable. If they are too high, they cause you to lift your shoulder muscles. The idea is to sit straight up and be as relaxed as possible. When you use armrests, do not lean on your elbows or you risk compressing the ulnar nerve, which is near your "funny bone."

Bleecker: The new voice recognition systems, where you dictate to the computer instead of using the keyboard, are intended to prevent stress on the hands and wrists. But we find that they are raising new problems. Long hours of talking can produce a dry throat, coughing episodes, lower voice pitch, temporary loss of voice and fatigue.

One way to prevent this is by humming occasionally. It's good for the larynx. Also, since voice changes with posture, stand up and talk (if you are using a headset, don't forget to put a long cord on it). To reduce the static load on the vocal chords, you can also try maintaining a higher pitch than you would normally use.

Finally, don't forget to take frequent breaks if only for a minute, and try to vary input devises among your voice, the keyboard and the mouse.

Bleecker: If you talk on the phone frequently, headsets are a must. For long calls or conference calls, use the speaker phone. Some people have found it helpful to use moveable armrests, which attach to the edge of the work surface and support your arms while you type – yet still allow your arms to move easily.

Above all, though, pay attention to your body. When there's discomfort, rest and try to figure out what the ergonomic stress factor is. Then modify it as soon as possible.