Well I promised Dana I'd start a thread on this, so here we go.
Actually the concept is exercised in the classic Olympic-style power clean.
Power Clean
The explosiveness is developed two different ways:
1) First is the exploding extension of the three joints (hips, knees, and ankles) in the initial phase. The goal here is to get the fast twitch muscles heaving the weight straight up, as high as they can heave it up. The hands and arms are merely transferring the energy of the extension of those three joints to the weight. (First five frames of the exercise on the web page).
2) Once the weight has pretty much defined its final height (frames 1-5) and the person guides it as close to the shoulders as possible with comparatively less upper body strength (frames 6-7), the individual then throws his body under the weight (frames 8-9). That second phase (barely seen on this WebPages because the person really isn't challenging himself) compresses these same three joints, which triggers a massive stretch reflex. Thus the exercise transitions from fast twitch muscular to neuromuscular.
So...how does this relate to a karate thrust? Well many serious actions in karate involve an action down to the floor from the center (from just above the hips down), and a reaction toward the target (from the hips up).
One way to do it is to extend all joints at once, as in the beginning of this power exercise. A tournament fighter that must rely strictly on speed will often do this for a "point." If one only emphasized the first phase, that's all one could do.
Another way to do it is to take advantage of the neuromuscular reflexes seen developed in the second phase of this Power Clean exercise. When a basketball player jumps up for a rebound, what is the first action? DOWN! Why? Of course he needs to lengthen muscles a bit (squat) to get to the peak strength zone for a good jump. But the compression phase done in just the right timing will trigger a stretch reflex. Thus there is a neuromuscular response that will aid in the leap to the rim.
When you think about it, there are electrical things going on in the body here. No wonder the chi-sters talk about strange energy flowing through the body!
Now, what was Dana doing? Well actually Dana had a fourth "joint" involved in her compression. She was allowing her pelvis to pop out of sanchin, and then was popping it right back under at just the right time. In fact folks like Dana use a whip-like wave action rather than a synchronous joint movement when attempting to elicit a compression and subsequent neuromuscular response. Dana talked about how master Nakamatsu first got them "thinking" about it. They would go way back down on the back leg until the joints were screaming. They would also extend the abdominal muscles by sticking the butt out, or as Dana said "forming a crease at the back femoral area." Then she would extend with the lower parts of the body (the first three joints), and then snap the pelvis under when the energy wave passed through the abdominal region.
Methinks that in practice it is quite sophisticated. Dana talked about it taking several years to get her own "jing". I don't believe it is simultaneous compression at all, but rather a wave going down and up through the body. A good baseball pitcher understand that well. In watching a pitcher wind up and fire, you can see the joints apply their forces from bottom to top at the last part of the motion. Each joint is further compressed when the energy wave goes by it, and then adds its response in just the right timing. Screw up the intra-body timing and you don't get that magnification action up the body from joint to joint.
The same is true for a sanchin thrust with jing (methinks...), but the final product must make this "wave" happen in smaller and smaller waves. The joints actually move less and less as you understand it is just as much timing as it is grunting. In a way, it's like how someone doing a hoola hoop will move the body less and less as they get the hoop going faster and faster.
I can get that nice whip action in some techniques. But the sanchin thrust presents quite a challenge, because the form and the system demand everything be done small and subtle. Dana makes it look easy. It most definitely is not.
I hope I got the conversation started right, and didn't mis-speak any of what Dana is doing. I'm eager to have her step in and either clean up my mess (
) or confirm and add to my understanding.- Bill
[This message has been edited by Bill Glasheen (edited August 14, 2002).]
