Re: Skin IS Structure Video 2
I think overall the idea represents a "piece" of the foundational components of IS. You're carrying too much tension in the shoulders when you raise your arms over your head and you break connection when you do the body lunge up - there's a very tangible disconnect between upper and lower body. Skin is a wrapper/container for the muscles, ligaments, tendons, fascia, etc. that can be conditioned over time to be more connected, stronger and better transmitters as the bridge of the "powers" of heaven and earth.
The definitions around those latter two seem to vary, so while I have my own biases on them, I'll say it's sufficient that the two "types" of power both require a connected body incorporating all the elements I mention above, which requires a level of physical work and conditioning (a lot of the aiki taiso can be repurposed - as they likely were originally intended to be - towards this pursuit) along with the requisite skill required to mentally trigger/activate/engage the connection points and manage the sum of the external forces acting outside and the internal forces within you for more practical applications.
So, I think the Skin as a drum idea is a nifty device, it's still only one instrument in the band and all of them are required to get tuned up in order to make music.