In 1984, only 25 percent of the population used computers every day in their jobs. By 1993, that number had climbed considerably to an estimated 45 percent and has continued to climb ever since. The Occupational Safety and Health Administration estimates that over 18 million workers must perform extensive keyboarding as part of their jobs.

Although computer use has undoubtedly dramatically increased the speed at which some tasks can be accomplished, it has introduced new problems into the work place. Among the complaints often heard are musculoskeletal problems including pain in the back, neck, and arms, as well as general muscle pain, stress, and fatigue.

Musculoskeletal injuries resulting from working at the computer can be caused by poor posture and work habits developed by workers, but often is the result of poor workstation design, office environment, job design, or a combination of these factors.

Sitting for long periods of time making only small, frequent movements of the eyes, head, hands and fingers can cause muscle fatigue, and over time could lead to pain and injury, including carpal tunnel syndrome and tendinitis.

The good news is there are steps that can be taken to reduce stress placed on the musculoskeletal system during computer use.

It is important that workers maintain good posture while they are working at the keyboard. This helps the body rejuvenate itself and function at top capacity. Additionally, frequent breaks from keyboard work, or mixing of tasks throughout the workday will also help. But perhaps the most important aspect of protecting workers from musculoskeletal injuries while working at the computer is proper workstation design.
 

Workstation Design Ergonomically designed workstations need to: Be comfortable, with easy access to the various components of the space. Provide posture support for the back, arms, legs, and feet. Utilize chairs, tables, monitors, keyboards, and other elements of the workstation that are as flexible and adjustable as possible. Be designed to compliment the type of work that needs to be done.

It is also important to understand that different employees have different physical needs and requirements, which may affect the design of each work station. Equipment should be adjustable to fit each worker.

Chairs
The height of the chair from the seat to the floor is critical in preventing back injuries and improving work performance. The top of the seat of the chair should be the same distance as it is from the floor to the crease behind the knee, when the soles of the feet are resting on the floor or footrest. The back of the knees should be slightly higher than the seat of the chair, allowing for a free flow of blood.

The seat of the chair should be slightly concave, with soft, padded, rounded or "waterfall" edges, which helps distribute the weight. The seat should be either angled so it is lower in the back, or may be slightly forward to cause less stress on the lower region.

Armrests should be low and short enough to fit under the workspace desk area. The backrest must support the entire back.

Monitor
The computer monitor should be about 18-20 inches away from the operator, with the top line of the screen not higher than the user's eyes. The screen and the document holder should be the same distance from the operator and they should be close enough together to allow for minimal movement of the neck or back when looking from one to the other.

Bifocal wearers, who have a tendency to tilt their heads back to see through the bottom part of their glasses, should either lower the monitor or use single lens glasses.

Keyboard
Keyboards should be detachable and should be positioned so the users forearms are parallel to the floor and elbows are at the sides. The wrists should be in line with the forearms. A padded wrist protection or rest can help keep the hand, wrist, and elbow aligned.

The mouse should be located at the side of the keyboard, close enough to the operator so it can be moved with the arm close to the body for support. The upper arm should not be elevated or extended. The top surface of the wrist should be flat, not angled. A mouse rest can help.

Complete the Video display Terminal Checklist to determine how safely individual work stations are designed.