HISS (the Historically Informed Summer School) has a tutor couple who as well as doing their instruments (lute and viol) are certified teachers of the Alexander
Technique. Makes quite a difference. Jake the lutenist is the most laid-back performer I have ever seen. As he points out, if you look at historical pictures of performers on instruments like the lute that have a bad rep for ergonomics, you usually find that they solved the problems centuries ago. You don't see any agonized folk-style contortions among early music mandolin players.