The first thing everyone needs to know is what causes the most common of repetitive strains: Carpal Tunnel Syndrome. It's medical name is Median Nerve Entrapment. If someone misuses their hands to the point that they inflame the long flexor tendons in the forearm and wrist, the inflamed tendons which now takes up more space, has no place to go. There are bones on one side of the wrist and the traverse carpal ligament on the other. So when the tendon inflames it presses on the only other tissue in the tunnel - the median nerve. Much like sitting between two overweight people on an airplane. The symptoms of a crushed nerve are pain, numbness and tingling. The reasons for the inflammation are quite easy to understand. The most common is a break in the wrist while performing repetitive tasks. The other is dual muscular pulls. Obviously we can only move one body part in one direction at a time but we often move our fingers in two directions at a time. We may flex one and either abduct or extend another. Even though we can do this, the extender and flexor muscles are still interconnected and we are using both at the same time. This act of tension usually puts all the strain on the tendons. In the piano world, our teachers either tell us to practice more, build up the muscles or relax. That is all bad advice. Practicing more bad movement, building up the wrong muscles and relaxing the wrong muscles will only create more problems.
When someone develops symptoms of median nerve entrapment they go to see their doctor who then begins to treat the symptom. They may ask what you think caused the strain and may suggest that you stop doing it for a while. This logic is greatly flawed. If you are moving incorrectly and rest for a while, the inflammation may indeed dissipate however, the erroneous movement is still part of you and when you take up the practice again, the problem will still be there and the symptom will come back. Symptoms are actually good. They tell us that something is wrong. Fix what is wrong, not the symptom.
Other treatment options may include anti inflammatory drugs, cortisone injections (which do a lovely job at dissolving tissue), splints which goes against everything we know about movement or, surgery, which is often totally unnecessary.
The actual solution and "cure" is simply movement re-education. The patient needs only to learn how to move properly. This could include not bending or twisting the wrist, not moving the fingers while bending the wrist, learning to not use tiny muscles to do some movements but instead use the larger muscles which are naturally designed to do that movement, learn the proper alignment of the arm and how it is the arm that must support the hand and not the hand moving independent of it, avoiding dual muscular pulls which can be crippling to the hand.
Not everyone has the capacity, patience, intellect or determination to heal. We've come to beleive that a doctor can fix our problems and we all want a quick fix. Who wants to spend months or even years learning to undo bad habits when a doctor can make a slice with a scalpel and like magic, the issue seemingly disappears. As I said, doctors tend to treat symptoms and not the problems. If the problem is we are moving incorrectly, we shouldn't be seeing a doctor. My favorite analogy to use is if your wheels are out of alignment and wearing down your tires, you don't just get new tires, you have to fix the alignment. If your body is out of alignment and wearing down the soft tissue in your wrists, you don't just make room for the inflammation by having surgery, you need to fix the alignment.