Ergonomics and Input Devices

Any office worker will tell you that working at a desk all day can be extremely uncomfortable (see Fig. 1). Sitting all day and using a computer can be even worse. Not only docs the user's body ache from being in a chair too long, but hand and wrist injuries can result from using a keyboard and mouse for long periods. Eyes can become strained from staring at a monitor for hours. Such injuries can be extreme, threatening the user’s general health and ability to work. Much is being done to make computers easier, safer, and more comfortable to use. Ergonomics, which is the study of the physical relationship between people and their tools—such as computers—addresses these issues. Now more than ever before, people recognize the importance of having ergonomically correct computer furniture and using proper posture and techniques while working with computers.

Repetitive Stress Injuries

The field of ergonomics did not receive much attention until a certain class of injuries began appearing among clerical workers who spend most of their time entering data on computer keyboards. One type of

RSI

that is especially well documented among computer users is carpal tunnel syndrome, a wrist or hand injury caused by using a keyboard for long periods of time. The carpal tunnel is a passageway in the wrist through which nerves pass (see Fig. 2). In carpal tunnel syndrome, tendons in the tunnel become inflamed because the victim has held his or her wrists stiffly for long periods, as people tend to do at a keyboard. When the tendons become inflamed, they press against the nerves, causing tingling, numbness, pain, or the inability to use the hands. Carpal tunnel syndrome is the best-known repetitive stress injury. It can become so debilitating that victims can miss weeks or months of work. In extreme cases, surgery is required.

Avoiding Keyboard-Related Injuries

If you use a computer frequently, you can avoid RSIs by adopting a few good work habits, and by making sure that your hardware and workspace are set up in an ergonomically friendly way. When setting up your computing workspace, make it a priority to choose a comfortable, ergonomically designed chair (see Fig. 3). Your office chair should » Allow you to adjust its height.
» Provide good lower-back support.
» Have adjustable armrests.
Your desk also should be well-suited to computer use, like the one shown in Fig. 4. The desk should hold your keyboard and mouse at the proper height, so that your hands are at the same height as your elbows (or a few inches lower) when you hold them over the keyboard. Here are some other tips that can help you avoid RSIs while working with your keyboard and mouse:

• Use an Ergonomic Keyboard

  . Traditional, flat keyboards are not well-suited to the shape of human hands. An ergonomic keyboard allows you to hold your hands in a more natural position (with wrists straight, rather than angled outward) while typing (see Fig. 4).

Fig. 4: Ergonomically designed keyboard.

• Use a Padded Wrist Support

  . If you type a lot, a wrist support can be helpful by allowing you to rest your hands comfortably when you are not actually typing. Remember; however, that you should never rest your wrists on anything—even a comfortable wrist support—while you type. Use the support only when your fingers are not moving over the keyboard.

• Keep Your Wrists Straight

  . When typing, your hands should be in a straight line with your forearms, when viewed either from above or from the side. Keeping the wrists bent in either direction can cause muscle fatigue.

• Sit Up Straight

  . Avoid slouching as you type, and keep your feet flat on the floor in front of you. Avoid crossing your legs in front of you or under your chair for long periods.

• Learn to Type

  . You will use the keyboard more efficiently and naturally if you know how to type. If you "hunt and peek", you are more likely to slouch and keep your head down while looking at rite keyboard. This technique not only slows you down, but it leads to fatigue and stiffness.

• Take Frequent Breaks

  . Get up and move around for a few minutes each hour, and stretch occasionally throughout the day.