medtner's words of wisdom?

[andhow04]

medtner wrote this:
"Rachmaninoff's technique­, his energy, his strength, speed and clarity ­is based on shaking-out movements from the inside."

that strikes up a strange and long lost memory of a teacher who told me to play piano in a relaxed way one has got to "shake out, like a wet dog!" Im fascinated.
it seems like medtner is referring to something rather specific. can anyone lend some more concrete insight to this? is this referring to the "vibrato" motion, as taught by liszt, godowsky, and the like???

[rimv2]

Study tai chi

You'll get what they're talking about