OFFICE ERGONOMICS AND CUMULATIVE TRAUMA DISORDERS By WILLIAM T. SUNLEY, Engineer of Local Roads and Streets

With more and more work being performed in an office environment, an increasing number of personal and mainframe computers are becoming an integral part of the office. According to 1991 OSHA estimates, anywhere from 40 to 80 million video display terminals (VDTs) are in use throughout the United States. One would think that because work is being performed within the office that the risk of injury is negligible. Grained, strenuous physical labor is the largest cause of on-the-job injuries; however, an increasing number of cases are being caused by office related incidents.

It is estimated that musculoskeletal disorders such as back injuries, carpal tunnel syndrome, sprains, and strains are responsible for 30 to 40 percent of all workers compensation claims. The American Academy of Orthopedic Surgeons estimated in 1984 that overall, repetitive motion disorders cost $27 billion a year in lost earnings, employee retraining, and medical expenses. Cumulative Trauma Disorders account for an increasingly large percentage of these costs.

Ergonomics is the study of the relationship between people and the work they perform. The goal of ergonomics is to fit the job to the worker, not the worker to the job. All too often, adjustments are made to the worker rather than the work environment, and over time this can lead to Cumulative Trauma Disorders.

Cumulative Trauma Disorders (CTDs) are injuries to the muskuloskeletal and nervous systems caused by repetitive motions, high force and awkward body positions. CTDs mainly occur in the neck, back, arms and wrists. Common CTDs include carpal tunnel syndrome, tendinitis, DeQuervian's disease and trigger finger. Other CTDs involve hearing loss through repeated exposure to noise, back disorders and a range of potential health effects related to operation of computers. CTDs can happen to anyone regardless of age or sex and may take months or even years for symptoms to appear. Common causes of CTDs include compression on hard and sharp objects such as resting your arms against the edge of a desk while writing or typing; sitting hunched over in a chair; or reaching for something while seated.

Although the risk of developing CTDs is always present, simple preventative measures can help to minimize the risk. As children we were told to "sit up straight" and to "keep your elbows off the table" with hopes of promoting good posture. As meaningless as they may have seemed at the time, they are valuable pieces of advice today.

Correct posture is a major part of preventing CTDs. While working at a computer terminal, typewriter, or writing, there are eight steps to remember for good posture.

1. The neck should be straight or slightly forward, while keeping both the neck and shoulders relaxed.

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2. Arms should be below shoulder level.

3. Elbows should be close to the body.

4. Forearms need to be parallel to the floor.

5. Hands and wrists should extend naturally from the forearms. An inexpensive wrist rest can help.

6. Keep the spine in its natural "S" shaped position.

7. The angle between the trunk and thigh should be greater than 90 degrees, and the angle between the calf and thigh should be greater than 60 degrees. An adjustable chair will help maintain the desired posture. Sitting with legs crossed and tucked under the chair or sitting on one or both legs will prevent natural blood flow, tighten and cause stress to joints in the lower extremities, and cause loss of nerve control.

8. Keep both feet flat on the floor.

To maintain correct posture while working at a computer, position the monitor so its top is at eye level, even with your horizontal line of sight. The screen, or monitor, should be about 18 inches from your eyes and tilted back about five degrees. If this causes a glare, install a glare filter, or adjust the lighting. To minimize head and eye movement while typing you might want to use a document holder placed at the same height and as close to the monitor as possible. The keyboard should be about two and one half inches from the top of your work surface to the top of the spacebar, and coincide with the 90 degree angle between the upper and lower arms.

Even with correct posture, sitting for long periods of time can be tiring and stressful. Stretch occasionally, look away from your work and, if possible, walk around.

Cumulative Trauma Disorders are not just office related. Any job which requires repetitive movement over extended periods of time can lead to CTDs. The goal of office ergonomics is to reduce injuries caused by physical stress on the body. During an average work day, you make hundreds of decisions that affect the amount of physical stress placed upon your body. These include the way you sit, organize your work area and perform your job. By understanding and respecting the causes of CTDs, you can reduce your risk of being one of the millions of individuals suffering from Cumulative Trauma Disorder.

Credits to: Mark Blankenship, Program Data Management Unit Chief

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