The amount of energy needed for Internal Development is tremendous. Physical yes, everyone assumes that it will be arduous and bitter, but the mental requirements exceed, by far, the body part of MInd-Body Training. Rest AND recovery is essential. I have a specific program of self-care that helps students' understanding of active and disciplined recovery, not just hitting an arbitrary sleep duration target.

How Sleep Flushes Neuronal Tissue - https://en.wikipedia.org/wiki/Glymphatic_system

I teach that fascia is important. If you break it, you suffer greatly, so follow instructions.

Student asks,

"Can you do things with the fascia? Can you fight with the fascia, can you feel the fascia? etc"

I answer,

"Everything you do relies on the fascia, but you can't manipulate it directly. Besides, the indirect experience of the fascia doesn't feel anything like how the anatomy looks."

I do talk about qi, and FaJin, and other esoteric phenomena. However, only as an aside to the training methods that actually produce the effect. For a number of years there's just no point. After a certain stage of development, you will come to me and say, "There's this feeling that I get. What's up with that." I will answer, "Oh, that's not important, keep training exactly as directed." Later, at another stage, you will tell me, with some confidence, what it is.