Thanks for the reply. I went back to the section of the video, studied the transcript, and agree that your interpretation is correct. At one point, Yang Zhen Duo even uses his fingers to show the interaction of the force vectors (my term, not his).
By the way, I paid attention to the tones this time, since I had not listened to the Chinese for a year or so, and definitely heard "cheng1" this time. I realize that I had earlier misheard a drop in pitch in one of the repetitions as the beginning of a second tone, and this had become fixed in my memory.
As for "deng," it still sounds to me like a pretty clear first tone, but my track record has not been good. By the way, I just received Yang Zhen Duo's book and noted the character you mention with the foot radical in the passage Jerry had picked out.
Language issues, aside, I still wonder a little about what if any sensations the legs should share. When the Yangs pick up their legs, for instance, between Lifting Hands and White Crane, I think I see something going on. Perhaps it is just the same lengthening that they usually demonstrate in the arms.
Thanks again for your correction and added information.