An Ergonomics Overview
Here is a brief discussion of specific cumulative trauma injuries, and the basic concepts of ergonomics which help prevent them.
A common injury is tendonitis - inflammation of tendons, which connect muscle to bone. They are prone to damage when overstrained by repetitive use or tense muscles. Since there is little blood flowing in tendon tissue, healing takes a very long time, thus the potential for extended disability.
Nerves may be injured by repetition, friction, and pressure. Carpal tunnel syndrome (CTS) involves injury from pressure on the median nerve that travels through a tight space in the wrist - the carpal tunnel. This nerve delivers impulses to much of the hand, and returns sensory information to the brain. Symptoms include loss of coordination, weakness, tingling and numbness, and cold hands and fingers.
CTS is often misdiagnosed. For instance, if there is tingling in the pinkie finger, it would not be carpal tunnel syndrome, because the media nerve does not distribute to the pinkie. That would be an ulnar nerve compression. If you have pain in your wrist, that is not carpal tunnel. Symptoms are always in the hand. Surprisingly, many general practitioners still use CTS as a broad term for all computer discomforts. It is a very specific injury, and it is crucial that you understand the real anatomy of these maladies.
At the root of it, these problems begin with circulation. The bloodstream must supply fuel to the muscles and cleanse the wastes they produce. This process is disturbed by overuse. The blood can't keep up with the demand being made by constant muscular use in the arms, aggravated even more by slumping, which can limit circulation into the arms through the shoulders.
Freely flowing blood is also limited by uninterrupted or "static" contractions. When a muscle is exerted, the bloodflow is greatly reduced. At the computer, we do many static contractions, but because they don't involve great effort we tend not to notice them until we feel the pain. Holding the shoulders up, keeping the head in fixed positions, keeping the hands raised over the keyboard, keeping the trunk supported in a chair that doesn't support us. All of these are cumulative static muscular effort that leads to tightening of muscles, pulling on tendons, pressing on nerves. When it is the pattern in the way you work, hours each day, multiplied by stress, this is the formula for injury.
Or at least considerable discomfort. This pattern is avoidable simply by learning some simple work habits, and taking the time to make comfort a priority in your workspace.
Where to Start
Prevention of these problems begins with "Ergonomics," the science of adapting our bodies to our tools.
Cumulative trauma injuries are truly preventable. Prevention does not have to be expensive. The investment required is tiny compared to the costs of lost time and productivity, medical and insurance costs, and rehiring and training that too many businesses have already suffered. More to the point, safe computing means healthier employees in an environment of higher morale and creativity. The time you take to learn more and make adjustments is the best investment you can make.
Additional ergonomics articles from Onsight