Preventive Medicine for the Computer User

Ergonomics and Repetitive Strain Injuries

First Published: Multimedia Online
Date Published: 1996
Copyright © 1996 by Kevin Savetz

After a few hours working at your computer, do you walk away in pain? Do your hands hurt? Is your vision blurry? Does your back ache? For many computer users, those little aches and pains are all too common. You shouldn't ignore those nagging pains--they are indications that something isn't right about how you work. Careful thought and preparation can prevent these little problems, and can keep them from becoming big problems.

The most common health problems experienced by computer users are eye strain, wrist or arm pain, and neck and back pain. These problems shouldn't be taken lightly, as they can be indications of larger health problems. Even those of us who don't spend six or eight hours in front of the computer each day can suffer from them.

Repetitive Strain Injuries

Typing and using a mouse put a lot of strain on your hands. Pressing the keys, squeezing a mouse, and holding your arms in front of you for an extended period each place stress on your body. By continually placing these sorts of strains on yourself, you stand the chance of developing a "repetitive strain injury" (RSI.) Repetitive strain injury is a term used to describe any injury caused by a repetitive activity, such as typing. Computer users aren't the only sufferers of RSIs--you can get one using a cash register, playing the piano, driving, or even using a hammer. RSIs are also known as CTDs: cumulative trauma disorders.

Dan Wallach is a graduate student studying computer science at Princeton University. He is publisher of the Typing Injuries Frequently Asked Questions List, an archive of information about typing injuries, keyboards, mice, desk chairs, and related subjects. Wallach began publishing the FAQ in 1991 when he got hurt.

During a summer job that required many hours of typing, Wallach developed tendonitis, a type of repetitive strain injury. Initially the disorder was only in his right hand, but it later spread to his left as well. "I taught myself how to mouse with my left hand, and brush my teeth with my left hand," he says. After several attempts, he found a doctor who understood the problem. "They made me custom wrist splints and gave me hand exercises. But I didn't really start getting better until I was done with the summer job, and wasn't typing all the time."

He began researching ergonomic keyboards, and he posted his findings to the Internet. At the same time, he started collecting information from the "sorehand" mailing list, a discussion group devoted to issues surrounding repetitive stress injuries. Over the years, his archive of information collected from the mailing list has become vast.

Wallach says what is echoed by many RSI sufferers: if you are careful, you can avoid the symptoms of RSI. If you aren't, the problems will return. For RSI sufferers, avoiding pain means small but important lifestyle changes. For instance, Wallach can't type on a "regular" keyboard anymore: he sticks with his ergonomic Kinesis keyboard. "My life had changed, but I am still leading a perfectly normal life," he says.

Today, Wallach works at a customized desk, in an armless desk chair, on an "ergonomic" keyboard, while wearing gloves to keep his arms warm. "I have had various flare-ups over the last few years, but by following a collection of small and fairly common sense rules, I consider myself pretty much recovered," he says. A carefully planned workspace is key to avoiding eyestrain, trauma disorders and back pain. There's a word for it: ergonomics. Wallach's FAQ defines ergonomics as "the science of adjusting your work environment to fit your body and make it most comfortable."

Wallach is not alone. The number of cumulative trauma disorders reported by private industry is growing by about 7 percent each year. According to the Bureau of Labor Statistics, in 1993, 302,400 "repeated trauma injuries" were reported, accounting for nearly two-thirds of total workplace illnesses. Computer users are not the only sufferers of trauma injuries--industries with most RSIs include motor vehicles and equipment manufacturing, meat packing, aircraft, clothing makers and grocery stores.

"With repetitive stress injuries," says Adam Engst, the operative word is 'stress.' It doesn't necessarily have to be physical stress." Engst makes his living with computers--he is author of the Internet Starter Kit books and editor of the TidBITS online newsletter. He learned that he had carpal tunnel syndrome in 1993. Engst says that lifestyle changes like a move, marriage or financial woes can affect your hands as much as heavy computer use. "What made the difference was learning to relax, taking breaks, and putting the desk at the right height," he says.


Are those funny-looking ergonomic keywords worthwhile? Some are, but you need to try a keyboard to see if it fits you well. You would test drive a car before buying one, and sit in a chair before purchasing it--finding the right keyboard is no exception. "Various keyboard vendors have addressed different things--which ways are your wrists bending, for instance. You want them to be straight as possible. Your elbows should be at your side, your hands straight forward," Wallach says. The Kinesis keyboard works for Wallach, but relies heavily on use of the thumbs. If you have bad thumbs, his favorite keyboard won't be right for you. Many other keyboard options are available, including "chording keyboards" that let you type with one hand by pressing combinations of buttons simultaneously, and even dictation programs that do away with the need for a keyboard and mouse altogether.

Wallach suggests enlisting somebody to watch you while you work at the computer. Have your friend to look for bad posture--are your shoulders hunched? (They shouldn't be.) Are your feet flat on the floor? (They should be.) Do you crook your neck to one side to hold the phone while you type? (You shouldn't.) Do you hang your head forward while typing? (This can strain your back muscles.)

Engst's carpal tunnel syndrome forced him to give up computer games. Prolonged hammering on the keyboard, usually with force, exacerbates his condition. "If the action is any kind of a shoot-em-up, or Doom, I avoid it like the plague," he says. For Engst, stress is as important a factor as keyboarding. The tension that comes with playing games is as hard on him as the keyboard itself.

Mousing Around

There are also a variety of mouse alternatives available that can ease hand strain. Gripping a mouse and making the small movements of clicking and dragging can be tiresome on your hands and wrists -- for some people, a trackball or trackpad is welcome relief. As with keyboards and furniture, no pointing device is right for everyone--one size does not fit all.

Engst recommends using a trackball rather than mouse. With a trackball, you don't need to move your entire arm to make a very small on-screen motion. Larger buttons on the trackball are easier to manipulate than tiny mouse buttons, so your hands and fingers need to do less work.

A less expensive alternative to a new pointing device is learning the keyboard equivalents for the mouse commands you use. By using the page-up and page-down keys instead of the scroll bars, for instance, you can reduce strain on your hands.

"Most people seem to screw up their hands on mice, not keyboards," Wallach says. The worst thing you can do with a mouse is click-dragging. Pressing down with the fingers cuts off blood flow--extended dragging is bad news, and in most cases is not necessary."

Eye strain

Your eyes are as important as your wrists. By taking some time to evaluate and structure your work environment, you can reduce eyestrain.

Placement of your monitor and keyboard are essential--the keyboard should be centered in front of you, and the monitor should be centered behind it. It's common to place your monitor too close or two low, which can increase eyestrain. If you extend your arm outward, parallel to the desk top, while sitting in your chair, your hand should just touch the top edge of the monitor.

Adjust your monitor's contrast and brightness controls so that the screen is bright and readable. On some monitors, an overly bright setting will cause blurry characters. If you can adjust the colors of your programs, remember that black characters on a light grey background are easiest on the eyes.

A well-lighted workspace is essential. According to Wallach's FAQ, "A mixture of fluorescent and incandescent light is usually most pleasing. The most important aspect of lighting is to reduce glare and bright reflections from your screen, nearby glass, or shiny surfaces. Since light conditions change during the day this may require several adjustments while working."

Most importantly, remember to rest your eyes while computing. Stop working for at least five minutes once an hour, to let your eyes (and perhaps your mind) refocus. Even if you don't want to leave your desk, look away from the monitor every few minutes. Focus on a distant object, or close your eyes. It can only take a moment to give your eyes a much-needed rest.

What is the single most important thing you can do for your own preventive maintenance? According to Wallach, "the single most important thing is to learn to listen to your body. It if something hurts, stop that!" People hurt themselves by ignoring the small signs that indicate growing problems. If something does hurt, go see a doctor immediately. "Once it starts getting bad, it gets even worse in a big hurry. The difference of a couple days could mean a short recovery or an extended ordeal."

Sidebar: Types of RSIs

There are several types of repetitive strain injuries, including:

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Articles by Kevin Savetz