I worked with an inspiring pianist who’s body language was the opposite of mine. I squirm and contort. My legs and torso move in different directions and my head flings back and I close my eyes. I make weird sounds and I don’t mind any of this, I’m used to trying to not get in the way of what my body wants to do. It has it’s own instincts and I like the results.
But this other person was totally still. Feet still, spine erect, voice silent, eyes open. Sometimes when I was alone I imitated it and I had a completely new experience on the piano. I bet other people find it valuable to track whatever your body already does and then try to interfere with it, privately to see if anything is different in the music experience.