Repetitive Strain Injuries (RSIs) sometimes referred to as Cumulative Trauma Disorders (CTDs), have been around for decades. Long before computer terminals and their keyboards were ever created. They have existed in the industrial environment, where numerous functions require the constant movement of the fingers, with varying degrees of exertion. The wrist RSIs or CTDs that sometimes develop, carpal tunnel syndrome, tendonitis, etc. have been continuously studied and usually found not to be caused by what people did, but by how it was done.

It was found that people who completed their task with their hand bent to any degree from a straight, hand-in-line to the wrist position, became a prime candidate for an RSI. Unavoidable in some tasks, bending or arching the hand stretches and compresses tendons, ligaments and nerves.
Wrist pain is the usual warning at a potential RSI problem exists and task modification or instructions on maintaining a straight, hand in-line to the wrist position where possible, is the accepted preventative measure in the industrial environment.

Applying this knowledge to the office environment, it must seriously be considered that using keyboards is not the problem, but how the keyboard is used.
Why is it that typists did not have RSI problems? Quite probably it was because as part of their initial instruction, typists were taught how to sit in an upright posture, and how to position their hands. The problem is not that keyboards require too much pressure, typewriters always required more. In fact, part of the problem might be keyboard sensitivity. Remember this?
Typewriter keys were sufficiently resistant to the touch that users could rest their fingers and to some degree the weight of their hands on the keys. On keyboards, they cannot. When you combine keyboard sensitivity with the improper posture most people are sitting in, you are laying the groundwork for an RSI to develop.

Too many people sit in their chair leaning back. Sometimes this posture is forced by poor chair design but more often the person has not properly adjusted the chair they have. When an individual keys while leaning back, their arms must be held suspended in front of their body. A function for which the human body is poorly designed. Fatigue soon develops and the next thing that happens is keyboards are pushed back from the front edge of the supporting surface and wrists are dropped into a resting position in front. Or people simply press the heel of their hand against the surface supporting the keyboard, if its depth doesn't allow for the keyboard's movement. Either way, the hand is now deflected, stretching the tendons and ligaments and pressing the nerves. Again, it is not what people do, but how it is done.

Evidence supporting this conclusion has been in virtually every article written to draw peoples attention to RSIs or CTDs, especially those that have included photos. These photos commonly show an injured users hands at a keyboard with their wrists encased in some sort of brace, to prevent any deflection of the hand to the wrist. Although the braces restrict the completion of other, often simple tasks in the workstation and can be irritating, the articles point out that they became necessary to prevent further injury and allow the healing process to begin by preventing deflection of the hand. Does that mean that if the user had maintained proper hand position to begin with, they would not have required the brace?

A January 1992, article in the Toronto Star titled, "When Work is a Pain", included the above photo, showing a person keying with a brace on their right wrist. The article focuses on wrist and hand RSIs as some of the potential problems keying can cause, and the writer obviously wants us to focus on the encased wrist in the photo, to appreciate just how severe the injuries can become. But what we SHOULD be looking at is the persons LEFT hand and wrist.