I do ART (Active Release Techniques) for the upper body. It is very expensive, over $2000 per course, there are 3 modules, upper body, lower body, and spine, and they want you to renew every year for over $500. They don't do it in cheap hotels (the one I was in was $180 a night for 4 nights) and the areas they are in are upper class, so where I was I couldn't find a much cheaper hotel close enough. Probably not a problem if you live in the area.
It is quite hard on your hands and thumbs. Everything is done with the thumbs as the contact resisting the stretch of the muscle. As a massage therapist, I have to plan when I do it during the treatment. It is to be done without lotion/oil, so you have no glide on the skin. I sometime cheat with this when I have clients who can't handle some discomfort. It is not a pleasant technique to have done, it is at best uncomfortable. You will be working in people's armpits, literally hitting the joint capsule of the shoulder through the armpit, and glutes.
I will often ask people who want ART to come in shorts and a tanktop. Working on a table draped for some of it is awkward. Limbs are to move through their full range of motion, hard to do with a face rest in the way
With that said, I get amazing results with it. In 2-3 treatments I have gotten shoulders moving again, gotten rid of stubborn knots that weren't releasing, and significantly decreased pain for people. I have improved golfers elbows, decreased the symptoms of carpal tunnel and have seen greater strides in improving people's postures.
I am extremely glad I took the ART course, and when I get the funds I will take the other two. It was worth it for me, and the type of practice I work in and the type of clients I get.
Myrrha