Manfred Klose wrote
Isn't something colder like ice better for relaxing the muscles instead of something hot?
Good for the muscles if they are inflamed - though overdoing it can cause problems too. However that's only one aspect of the dreaded RSI. RSI often includes nerve entrapment - and ice ain't going to sort that out.
I have had problems with nerve entrapment in the left wrist, right elbow and neck (the latter is not RSI, it is some kind of bony growth and is "stable" IE not increasing). A good physiotherapist can do a lot for these kinds of conditions. They have methods of remobilising the nerves.
Going through my three areas of nerve entrapment...
1) Neck. Not actually an RSI in my case, but a bony growth akin to arthritis. This is "stable" IE not changing. So physio and daily neck stretches took care of that.
2) Elbow. This is quite common in guitar players, also tennis players. ALSO people who work with computers a lot. Some physios and osteopaths have stopped calling it "tennis elbow" and now call it "mouse elbow". This is the problem that had me looking for an ergonomically modified guitar, but in the end an ergonomically modified keyboard and switching the mouse to my left hand bought huge relief. Well... those changes and physiotherapy.
3) Wrist. Stop those sordid thoughts! This was carpal tunnel syndrome. Correct diagnosis of this included "nerve conductivity tests" which basically amounts to electric shocks in the arm! The surgeon was a conservative, "cut as last resort" type and recommended a regime of intense physiotherapy, but in the end surgery was required. This was successful and it's quick. However it involves cutting a ligament across the base of the wrist and so there is a time when guitar playing suffers. I found barre chords and chords that stretched the left hand difficult for a while - but you get through it.
There are options for ergonomic modifications to acoustic guitars. One is the "wedge"
see
http://www.elutherie.org/2007/03/linda-manzers-wedge-acoustic-guitar.html
The other is to get bevels put on the bout of the guitar that the elbow travels over
see
http://guitarsafrica.co.za/0269.html
However you usually don't get these in mass produced guitars so there are two options
1) Buy from a luthier who will incorporate these into your guitar at build time. The mods usually don't add that much to the price, but you have to buy a hand-made guitar.
2) Get your existing guitar modified by somebody who knows what they are doing. Which can be done but is not cheap and will just make no financial sense if you're playing a Cort.
So physio, exercise, appropriate stretching and maybe some habit changes are probably more realistic.
One habit I have to break is sleeping with one arm bent and the hand placed under the pillow. This keeps the elbows bent and thus stressed at night when blood flow has slowed down - not good for the elbow and also can further restrict blood flow to the fingers.
But you'd do better seeking out a good, sensible, physio than taking advice from me.
If you are getting tingling or numbness in your fingers then seek professional advice - those are indicative of nerve entrapment in elbow or wrist.
