Tim Fong wrote:
You seem to talking about the resultant forces from geometric motions? Have you tried motion capture or something like that, or any attempt to actually measure the forces you're talking about?
Others have already done that for quiet stance. See http://arxiv.org/PS_cache/cond-mat/pdf/9908/9908185.pdf
. The normal hip sway movements shown in that study are on the order of at least three distinct periodic intervals ~ 0.25, 0.5 and 1.0 cm (and possibly one or two more at smaller scales of resolution). The upper torso moves in almost precise counterpoise to the hip movement.
It would be interesting to try motion capture for techniques and particularly for strong kokyu movement to see what it might reveal. I have actually been thinking more in line of looking at EMG data folr balance and blending techniques. There is a nerurologist I know i might be able to draft into the effort to see if any useful study of balance modes can be made from aiki movement.
The author attributes the hip/torso movements as random or stochastic, but the existence of three distinct movement intervals and frequencies in his data diagram of that oscillation is a sign of chaotic behavior. Chaotic systems are paradoxically capable of disproportionate resulting changes from arbitrarily small changes in initial conditions, and also capable of maintaining a robust global pattern even in the face of large excursions in initial conditions. As a propect for a better model of the simultaneous sensitivy and relative imperturbailty of good kokyu, it is promisingly similar in effect.
The depiction given in that study cited suggests what I have suspected for some time - a figure-eight-ish path of the hip balancing oscillation. The shape of the data graph suggests to me a series of nested loop attaractors, but to see it clearly you would have to take that data and map it onto the 2D complex plane, or into a 3D phase space diagram. If you want a lay explanation of what that iis exactly, and what it would show, you can read James Glieck's book on Chaos or any recent college math text on Chaos or complex systems. Ther are also good web resources on this topic, too numerous to detail
What is interesting that I did not expect before reading the study, is that there appear to be sub loops of higher frequency oscillation nested with each arm of the figure eight, probably duplicating the same figure eight form, and possibly even one more layer of nesting loops at one scale below that.
This is fractal organization, which is the hallmark of self-organized criticality (SOC), a point that bears some serious consideraiton of its own for aiki purposes. O-Sensei described takemusu aiki as being led by kami to the right technique, or even awhollly new technique. SOC has been rigorusly examined by the likes of Steve Wolfram, to show how in such systems the structure of simple interactions themselve can develop very rich behavior that requires no conscious input to generate very complex and adaptive behaviors. I think you can see where that line of thought is headed.
Tim Fong wrote:
Re: the pressure/spring stuff. I don't actually look at the pressure stuff as a model. Rather it is a feeling in the body that is recreatable ... Again, I want to re-iterate-- it is NOT a model or even an analogy, but a way of training. I would certainly like to find out how and why it works.
I would not begrudge any imagery that helps make the physics of any complex perfomance work. Singing coaches tell you to imagine doing do all sorts of physically ridiculous things that nonethless have powerful resonance as an image and focus of where to direct the energy, and which really work to correct errors of form. The test of a teaching method is whether it helps to learn what is being taught.
I am trying to better desribe the physical attributes of what aikido does with the still scientifically mysterious process of human balance. I am following some concrete intuitions that I gained in flying helicopters for ten years. I sense that there is an applicaiton of the gyrodynamics that I understand from that experience to better understanding of the human balance system and from that to better understand aikido techniques. I see these rotiational dynamics in the hip sway balance movements, but I also see them in the more nearly instantaneuos gyration/rotations of individual joints. While the limb joints are moving slowly enough that more common lever/linkage analysis can certainly be applied without gross errors, anything that rotates also obeys gyroscopic laws, if manipulated in the right way.
From that, perhaps yet more teaching paradigms will be made possible that the traditional lagugage of description sometimes obscures needlessly. Not that what I am doing so far is exactly crystalline at the moment. The mirror is still quite dull, murky even, and it needs lots of polishing yet.