If you use your body efficiently and effectively you will have fewer problems with Repetitive Use Injuries. I don't think Alexander Technique is strong enough to overcome all obstacles on its own. It is best used in conjunction with other techniques. There are many different yogas, but the most familiar to Westerners is Hatha, or Yoga of Postures. Please see the bibliography for some good textbooks.
Yoga is great for musicians.
It is, after all, an integrated system of cleaning, purifying, stretching, and strengthening the body that is thousands of years old. Christian Lindbergh practices yoga. Yehudi Menuhin was another famous practitioner. These are powerful poses, and because they are static it is easy to misjudge and go too far. Only go to the point of a gentle stretch.