Ergonomics is the study of the laws of work; applied ergonomics is the science that considers the relationship between people and their workplace and aims to improve comfort, well being, and efficiency on the job. In other words, rather than fitting the worker to the job; the workstation should be adjusted to fit the person.

Improper workstation setup can lead to repetitive motion injures and other musculoskeletal injuries. The Occupational Health and Safety Administration (OSHA) reports that workplace injuries that are classified as musculoskeletal injuries are increasing. In fact, work-related musculoskeletal disorders (MSD) – such as tendonitis, carpal tunnel syndrome, and low back pain – are the leading causes of suffering and disability in the workplace today. According to OSHA reports, there are 1.8 million work-related musculoskeletal disorders each year. Of these, more than 650,000 result in lost workdays each year, accounting for over 1/3 of total lost workdays.

In addition to lost workdays, medical costs involved with treating MSDs are increasing and contribute to the rising cost of healthcare. Approximately $15-$20 billion is spent annually on MSD claims, with indirect costs at an estimated $60 billion each year. More than 10 million people seek treatment from physicians, chiropractors, and physical therapists for musculoskeletal disorders at costs exceeding $50 billion per year.

Ergonomic Considerations for the Seated Worker

The reports from the Bureau of Labor Statistics categorize the reported word-related disorders by the source of the injury or illness. The second highest reported source for these injuries is the workers’ motion or position. Organizational factors that have been linked to MSDs include lack of job variety, excessive or highly variable workloads, and high time pressure.

Nearly 70 percent of all work done in America today is performed while seated at work stations. A great deal of this work is performed at computers. There is a correlation between poor work posture and a variety of painful and disabling syndromes relating to the upper spine and neck. Some of these conditions include back pain; cluster, migraine, and tension headaches; elbow, forearm, shoulder, and wrist tendonitis; entrapment disorders of the wrist and hand, including carpal tunnel syndrome; neck stiffness, pain, and spasm; and thoracic outlet syndrome.

Chair Height and Position. Your chair should provide comfort and support for your body. Your chair height should be adjusted so that when you are sitting tall, your feet can rest flat on the floor (or an appropriate foot rest) with your knees and ankles flexed at ninety degrees. You should be able to sit with the small of your back firmly positioned against the lumbar support of your chair. When in this position, your seat should extend forward far enough for you to place three or four fingers behind your upper calf; this helps to prevent the restriction of circulation to your feet and lower limbs.

Desk and Monitor. When sitting upright in your chair with your elbows flexed at ninety degrees, the top of your desk should be about two inches lower than your forearms. Your monitor should be about an arm’s length from you with the top part of the screen at eye level. The tilt of your monitor may also need to be adjusted to reduce glare and maximize comfort.

Keyboard Ergonomics. When you sit facing your computer monitor, your upper arms should remain in a relaxed position with your elbows bent at ninety degrees and your wrists pointing forward. In this position, the keyboard should be placed just below your wrists and hands and should not exceed the reach of your fingertips. Twisting your hands puts strain on them. Resting on a wrist rest, the table, or arm rests while typing forces you to twist your hand to reach some keys. Instead, it is better to keep your hands moving freely above the keyboard, letting the strong muscles of your arms move your hands.

It is also a bad idea to contort your hands in other ways. For instance, some people lift their pinky or thumb while typing. Your hand should be flat, and parallel to the keyboard, without twisting. There should not be any pressure on your wrists or forearms while you type. You should NOT rest your wrists on a wrist rest except while taking a very short break from typing. A wrist rest of the proper height (level with the space bar) can also serve as a reminder to keep your wrists straight. If you feel your wrist touching the rest, you know that your wrists are starting to dip

Take Frequent Breaks

Many short breaks are better than a few long ones. Taking a break can be as simple as taking your hands off the keyboard and letting your arms droop at your sides. Every half hour, get up from your desk and stretch to loosen your neck and shoulder muscles. Try to take 10 minutes of breaks every hour, more if you need it. "Repetitive Strain Injuries, a Computer User's Guide", by Dr. Emil Pascarelli and Deborah Quilter, recommend the following rule of thumb, for those experiencing problems: see how long you can type without feeling any symptoms (pain, tingling, numbness, even just heightened awareness). Then subtract 10 minutes from this time. Don't type any longer than this without taking a break. By the way, if you can only type 10 minutes or less without symptoms, or worse, have symptoms constantly, then you shouldn't be typing (or writing, or anything else which causes problems) at all.

Stretch

Just as in athletics, stretching is essential for preventing injury. You should stretch your wrists before you start typing, and when you take breaks throughout the day. Note: If you already have symptoms of Repetitive Strain Injury, improper stretching can be harmful. You should see a physician before doing stretches. For some simple stretches that can be done at your desk, click here.

Practice Good Ergonomics

When you type, your wrists should be straight (not twisted in or out) and flat (not bent down or up). You should also avoid stretching your body into awkward positions. Your monitor and keyboard should be directly in front of you. If you are transcribing from printed material, use a copy stand so that you don't have to twist your neck or arms. Your keyboard and mouse should be within easy reach, possibly on a keyboard and mouse tray.

If you use a laptop, it may be difficult to achieve an ergonomic set up, because the keyboard and monitor are constrained to the same level, and because as you move from place to place it will be hard to get the chair, desk, etc. adjusted correctly. Consider buying an external monitor or keyboard.

Sources: Joseph, J. Sweere, D.C., Golden Rules for Vibrant Health in Body, Mind and Spirit (2004), Basic Health Publications, Inc.; Bureau of Labor Statistics. U.S. Department of Labor – injuries, illnesses, and fatalities; Occupational Safety & Health Administration (OSHA). The new OSHA: reinventing worker safety and health; Krause et al., 1998, Spine; Maloney, 2000, Modern Materials Handling; Occupational Safety & Health Administration (OSHA). Proposed ergonomic standard; Backsafe, 1997.