View Single Post
Old 01-15-2014, 12:20 PM   #26
Erick Mead
 
Erick Mead's Avatar
Dojo: Big Green Drum (W. Florida Aikikai)
Location: West Florida
Join Date: Jun 2005
Posts: 2,408
United_States
Offline
Re: Unifying the theories - Aiki & Levitating Chains

Quote:
Demetrio Cereijo wrote: View Post
Better at what?
That's the rub, isn't it. Outside of "do this-feel that" school of training (which I do not in any way criticize) there is almost no objective set of criteria to tell students what they are training for in their Aiki-taiso (they work to train this --done right); aikido waza (they work to train this- done right); weapons work ( they work to train this -- done right). To a practitioner who has "gotten it" in any degree at all, the "right" and "wrong" ways become progressively clearer to judge. But with little in the way of coherent objective explanation to aid the student in self-recognition of right or wrong manners of action, they are at sea, with no chart.

I do not think we are doomed to this though. My efforts at understanding aiki from a bio-mechanical perspective, have been fruitful, for me at least and for many of my students. I have made reference here to key aspects of angular momentum and the behaviors of chains -- particularly the bones considered as a chain of linked rods:

In a serendipitous discovery I recently saw a popular physics trick made the subject of a recent viral video, and which in the terms I now grasp -- seems to illustrate how this principle is directly shown in the behavior of a beaded chain falling out of an elevated bucket.

While a popular and instructive video, the author's conservation of momentum theory proposed as an explanation is wrong. The correct explanation is an understanding of the effect of DYNAMIC rigidity that occurs when a chain of rods is lifted by a continuous rotation:

Quote:
[T]he chain is more like a series of short, rigid 'rods', say the authors, who publish their results today in Proceedings of the Royal Society A1. In their model, each rod is made up of three beads and two connectors. The size of a rod corresponds to the number of beads it takes to turn a section of chain back on itself by 180 degrees (it takes six).

Picking up a portion of rod from the pot with an upward force on one of its ends causes two things to happen, says Biggins. It makes the rod lift, but it also causes it to rotate. The end that is not picked up pushes downwards, and the pot provides a reaction force, he says. "The far end of the rod under those two motions actually goes down, and therefore pushes down. And that gives rise to this extra kick from the pot which drives the fountain.
In other words, once one end of a chain of rods begins a cascade dynamically, the chain of rods as a whole begins to lift and rotate at the other end in a complementary manner. Under gravity, the induced drop over the lip of the cup on one end, is compensated by the lift on the other end, and because the chain under tension is dynamically rigid, a rotation is caused by the immediately lifting segment PUSHING down on the vessel -- which reacts with an equal push UPWARD -- not only adding momentum but because of the rotation of the lifting portion of the segment -- the reaction is a counter-rotation on the resting end of the segment up and outward.

This is a coincidence of contradictory forces in a spiral dynamic (aiki) - the pull on the chain coming out of the bucket (tension), resulting rigidity and reaction forces giving added push (compression) on the chain out of the bucket, and giving it rotation in addition to the added momentum.

In the chain shown in the video demonstration we see the operations of aiki age in the chain rising from the cup, and the action of aiki sage in the descending elements of the chain. In free action these same principles may be deployed laterally and spirally using one's center of mass (dantien/hara ) to the same effect as the more simplistic up-down dynamic of the chain trick under gravity. These dynamics are, by turn, the stiffer, whole body dynamics dominated by torsional stresses, or respectively by the looser, pendulum action as with free chains -- and freely shifting between the two modes -- which are, mathematically speaking, directly related.

Speaking from personal experience I find the the former is favored at early stages of introduction by Yoskinkan, for example, later moving to combination with looser action. Iwama follows a similar way of progression, though in Saito's more programmatic and methodologically different way. ASU is a more eclectic bag with a eye for the expression of "principles" expressed in Saotome's views, in both tighter and more loose configuration of actions, in Aiki taiso, tai-jutsu and weapons work; Tohei's approach was fundamentally focused on the Aiki taiso, sometimes (it seems to me at least) to the near exclusion of studying application (at least in some quarters).

Aiki is the development of the body's ability to naturally -- and ultimately reflexively -- modulate its own rigidities and flexibilities of structure under dynamic conditions to form -- or to defeat the formation of -- these kinds of dynamics in connected structures (another person's body/weapon).

What was near to being lost was the "feel" of the Aiki in the body communicated in the inimitably intuitive Japanese mode of transmission. Some are finding western ways to emulate that -- and to good effect it seems. What we stand to gain in addition is a more Western and better developed objective understanding of the art, to make its transmission less dependent on correct enabling of physical intuitions across culturally-bound modes of transmission which tend -- at least IMO -- to work less well in our culture.

Cordially,

Erick Mead
一隻狗可久里馬房但他也不是馬的.
  Reply With Quote