I have read the book. The danger I believe is due to the Golden Buffalo, Golden Turtle positions, where extended forward bend over of torso affects veinous circultion. There is very good parts in there about standing posture and the sacral and cranial pumps.

I know people that co-wrote or knew the editor. What wasnt left out of the book, the original copy was modifyed. And it was intended to supplement the seminars. Blah, blah same old story right?

The older forms of "qigong" were meaned to effect venous circulation or the flow of CS fluid. Which required extreme angles and use of gravity and pressue. This is just an example of that idea. When you start changing something to be safer, you often also throw the baby away and keep the bathwater.