Fascinating, and makes sense in terms of how much time is necessary to process and interpret visual information. Can you provide references to any research on this? I'm always interested in scientific explanations of things.
Not to steal the topic which is "methodology" -- but I have found ways to apply this kind of information helpfully, and less technically. But the tedious detail is here:
[spoiler] Visual reaction times: http://www.humanbenchmark.com/tests/...time/stats.php
average centers around 205 ms (with standard deviations roughly between 100-300 ms.
An average trained person person delivers a punch in about 300 ms. Danny Inosanto, Bruce Lee and boxer, Frank Bruno, were timed for their punches at just about 100 ms from a starting signal (likely audible, see the visual processing time info below), for a high end mark on voluntary reaction from accomplished martial artists. That is near the physical limit for two-way cerebellar-mediated action (nerve impulse from brain to limbs ~50-60 ms, one-way). These are polysynaptic reflexes -- involving more than one nerve path.
Spinal reflexes ( e.g -- the knee jerk (extensors) and "clasp-knife" (flexors) are monosynaptic (literally one nerve is involved) and are mediated by the Golgi organs and other kinesthetic signal systems sensitive to differential compression or tension, without the brain playing any real part (other than to inhibit their signals). These responses are on the order of 10-40 ms. http://www.jaoa.org/cgi/content/full/106/9/537
-- See figure 2. The interesting thing about these systems is that vibratory signals travel in the body at the speed of sound in water ~1500 fps, vice nerve transmission speed which is ~ 60 fps. They know what is happening in remote parts of the body and are acting in response before the higher nervous system even receives the signal.
For discriminated visual reaction (vice the linked "click test" benchmark study -- which is prompted (i.e. -- there is no "discrimination" processing required) the processing time, alone, is about 500-600 ms. http://homepages.nyu.edu/~bm1/Nature-Neu_2003.pdf
Add to that visual perception threshold the decision/reaction time 600+300 and you are near a second, for an average trained person. Or to put that in more practical terms, Danny Inosanto punched that average trained person five or six times while he was still trying to figure it out -- and three more times for spice while trying to do something about it
Even in higher level control tasks, kinesthetic guidance has a distinct advantage, both in shorter latent response (150 v. 250 ms) and shorter time to accurately grade that response to the size of the input (160 v. 200 ms): http://www.jneurosci.org/cgi/content/abstract/9/2/447
I suggest reading up on spinal reflexes and how they may be over-potentiated (e.g. -- the Jendrassik Maneuver). http://www.rettungsforum.com/php_fil...der/jendra.gif
) http://www.qwantz.com/shirt_jendrassik.jpg http://en.wikipedia.org/wiki/Jendrassik_maneuver
This is very suggestive of the mechanism for the whole-body perceptive/activation relation without much conscious mediation that seems endemic to proper aiki. The Jendrassik maneuver reflex (upper cross loaded, for those who use that as a reference) action actually provokes an involuntary stepping motion in the lower limbs, loaded and unloaded.
See -- http://www.springerlink.com/content/n44822007475w64q
Also, it seems that simple monotonic vibration can improve compromised balance systems in the elderly: http://www.sciencenetlinks.com/sci_update.cfm?DocID=195
It is reasonable to expect that the inverse using destructive resonance (see for effect, here: http://www.youtube.com/watch?v=HxTZ446tbzE
) can be used to compromise or disrupt an otherwise properly functioning balance system.
Resonance frequencies in the body are about 10 Hz -- oddly enough the frequency of furitama, (I have timed it). Vibrations of this type cause "negative viscosity" <<Plain language -- loosened structure>> in the limbs. http://www.pubmedcentral.nih.gov/art...?artid=1249627
Vibration of this type can also cause involuntary spastic clenching -- as anyone who has raked leaves vigorously for about fifteen minutes can tell you because their hands won't clench. This seems to be a myofascial action (similar to that of smooth muscle in the viscera) responding the oscillatory stress and is mediated by certain hormones, including histamine (which also provoke inflammation at impact sites) and much more interestingly, oxytocin, the "love" hormone. Here: http://www.fasciaresearch.de/wcb2006.pdf
True budo, neh?
As far as the thread topic here is concerned -- I have really emphasized feeling vibration and oscillation in both partners' structures in practice in every movement, every strike, every contact. When they are correct, his arm moves as one's own arm -- which is to say without muscular flexion (since I point out that I can't flex his muscles for him).
I emphasize this -- that if you do not learn how to move your own structures through a primary action that is not dependent on voluntary motor nerves and muscles in the limbs
-- you cannot learn to move your partner's limbs and structure in the same way. While you cannot connect his nerves to your nerves nor his muscles to your muscles and make those
your own -- you can
own his structure if properly connected by these other means.