Well, those are good clips of Sanchin (aka "San Jan" in the original Chinese that the Okinawans learned it from). Notice how soft it is. Ushiro Sensei is harder, but not as hard as the Uechi Ryu people on Okinawa. In other words, the "muscle-to-jin" ratio varies, according to the way different styles have interpretted, specialized, etc. The same question of "muscle-to-jin" ratio arises when learning the kokyu/jin skills of Ushiro Sensei and comparing those skills with what Ueshiba and others used in Aikido originally.
Is there a description/explanation on-line you could point me to? Also, I'm not familiar with this 6 direction exercise Rob speaks of.
Well, the 6-directions stuff is outside of the "baseline skills"... the point is that we can always point back to the ki and kokyu skills as baseline and develop all other skills, including whatever skills derive from techniques and motion, because the ki and kokyu skills MUST be the basis for all techniques or the techniques are wrong (no matter how "effective" someone describes certain techniques).
You haven't read Rob John's deathless prose??? Good heavens, that's tantamount to admitting you've never read a Superman comic book.
I'll see if I can find some URL's and pm you with them.