View Single Post
Old 01-14-2013, 07:29 PM   #21
Erick Mead
Erick Mead's Avatar
Dojo: Big Green Drum (W. Florida Aikikai)
Location: West Florida
Join Date: Jun 2005
Posts: 2,619
Re: Increasing Ground Awareness for Internal Strength

Michael Varin wrote: View Post
Yeah. . .

I don't believe it.

Not without some sort of collusion, conscious or unconscious.

Chris, what do you think would be occurring in such a situation?
Not Chris -- but not collusion either... Structurally, this is exploiting racking instability -- I've seen videos (of Okamoto I think), doing this one.

In the case of the man held up by several others -- it works in two distinct ways I have seen. One works by driving a spiral moment -- altering his point of support to drive a spiral wave around their support base and a resulting torque that eventually racks them twisting off their collective support bases. The other uses a more linear oscillation that -- like sloshing water back and forth in a shallow basin -- eventually overruns the containing boundary of their support. The man above just drives the top of the supports in resonance against their fixed bases -- just like pumping a child's swing -- but inverted - They have no inherent limit boundary for dynamic stability like the swing does (the suspending ropes or chains) .

Same basic principle is in play in the jo "trick".. ,, instances of applied shear across the perpendicular of the line of support and the inability of the supporters to actively coordinate their resisting support. In the case of the jo trick it is relatively linear projection and retraction oscillation that results in a driven torque oscillation (like ude furi) applied to the base support of the men holding the jo, which also builds in successive waves - at least as Ueshiba is seen doing it.


Last edited by Erick Mead : 01-14-2013 at 07:41 PM.


Erick Mead
  Reply With Quote