Re: What is "Aikido"?
I totally agree. IMHO and equally humble experience, you HAVE to keep it at a simple enough level for even the dullest blade in the drawer.... if you can't teach this stuff to a 9yr old, forget it.. you've lost them coz it's "too hard" to understand. What Ueshiba is doing in the chest push is really simple stuff (when you know how) and how to power it equally basic stuff (if you know how)... which Mike (and others) have already elucidated in numerous other posts. The gems are out there... look for them!
FYI, one of my teenage students of talented mediocrity (who needs to train more consistently!!!) was already able to do this very basic "bounce jin" from seiza after training with me for a mere 9mths. The crux of the matter is being able to teach this stuff to someone with little to no martial arts exposure in the shortest amount of time. My 9yr old son has been training with me for a year and he can already do most waza at a high enough standard that would put many adults that have been training a bit longer to shame.
If I tried to explain what I do in gyrodynamics, rotational dynamics, or angular momentum, he won't understand a word I'm saying. But if I use simple analogies like rubber bands, see-saws and rolling balls, he'll get my drift in a jiff.
Nice theory, for the academically minded, but I would seriously question the appropriateness and practicability.
FWIW, my teachers NEVER explained any of this in physics terms... always simple analogies...