Louis, I must confess I am confused about your statements about mechanics and hydraulics. I have never formally studied either physics or engineering and so do not know what formally distinguishes mechanics and hydraulics. Can you amplify further?
I also am not sure what defines a “machine.” Didn’t the Chinese design mechanical clocks run by flowing water? I think I understand “dissipation of energy within a system,” but this does not help me understand the significance of the point you are trying to make.
If I squirt a hose against the side of a house, the house will not move, but energy will still be applied against the house. The same energy can push along something lighter or something with less frictional interaction with the ground. Is this hydraulic or mechanical action? Whatever the right answer is, can you give an example of the other type of action so that I can understand the difference?
If I push a stick into the ground, I think it is clear how my pushing energy moves the tip of the stick deeper. If I push one tip of a relatively strong bow against a concrete sidewalk, most of my energy will be reflected (?) or deflected (?) away from the concrete and be dissipated (?) into increasing the bend of a bow. If I can suddenly move my hand away, the bow will spring upward. If the bow is extremely weak, but still springy, almost all my energy will go into the bend and little will be applied against the ground. The bow might still spring back, but it will not have the power of the strong bow.
As far as I know, the tendons and muscles in the legs do not in fact have the springiness of a bow, but why would what I have described above not apply to how we can use our legs?
Jeff, I have thought a lot about what you posted and am still unsure if what you are describing is what I have understood and what I do or something different. Linguistic images are tricky, and sometimes quite personal.
You quoted the following: “It is possible for the opposing force created by the push of the feet against the ground to be completely absorbed (or used up), due to the complex transmission system of the tendons, bones and joints. This force thus disappears without a trace.” Taken at face value, I agree 200% with this. It in fact states what I was trying to describe quite succinctly. If you push heavily against the ground, this force is transmitted through your tendons, etc. throughout your body, but is not necessarily seen coming through your hands. How much force is actually revealed in your hands depends entirely on what you do with your tendons. In form, you reveal nothing, since there is no opponent to push against. I advocate not stinting on the pushing force in your legs, at least initially, because you want to have this very feeling as the force threads through your body. Without this, how can you easily discriminate the feeling of “mutual constriction” mentioned by Yang Zhenduo?
Jeff, I think your intent is to use this quote in reverse to explain how a strong push against a practitioner need not manifest itself as an equal increase in pressure against the ground. Is this correct? If so, I again agree completely. My view, however, is that this is precisely not the feeling to cultivate during the Yangs’ form, because then one will not get a clear feeling of what it is to move Jin through the body and through the legs. Does this make sense?
“Thin ice” works very well for me as image indicating to use careful and precise stepping. This seems to serve virtually the same purpose as the image of the “stepping cat.” When someone is testing my posture for structure and root, however, the image of “thin ice” does not work for me yet. Without changing my body, I cannot figure out how one could control the amount of force being applied against the floor. If I change my body during the test, it is easy to control this force, as I stated above; however, then, my static posture is no longer being tested, but my ability to neutralize the force. Are you saying that if you were standing in soft snow and someone pushed on you, you would not sink any further as a result of the external force? Am I missing something non-mechanical, as perhaps suggested by Louis?
I guess that the way I would explain the importance of structure in Taijiquan is that you absorb force in such a way that it tends to reinforce your structure. To do this, you must reflect the force against the ground, but not try to have it all manifest itself against the ground. You use the difference to alter your joints, dissipate some of the force, and set up your counterattack. When you focus purely on muscular strength and let all the force apply itself against the ground, you have the feeling that your structure is always under threat of collapse and acting in opposition to the outside force.
One way in which “thin ice” does work for me as a metaphor is when one is about to lift an empty foot from the ground. Here the easiest and most natural thing to do is to push off against the ground. If one does this, however, one surrenders somewhat to the rule of momentum, which is not permitted in the Yangs’ form in most postures. For me, this is simply the reverse of how one is supposed to place one’s foot onto the ground—at first, without any transfer of weight or momentum, but then with a gradual shifting of weight powered by the legs. Stepping in this way does indeed work the lower back muscles and provide the feeling of extracting the feet from the mud. Is this what you mean, or do you have this feeling throughout the entire cycle of stepping?
Steve, I liked your post. For me, I think all of this is an issue of communication.
For anyone interested in answering, I am curious about the boat image as used in connection with defining Peng. Louis’s post above talks about “water floating a boat and of water flowing downstream.” I have a vague recollection of a slightly different image, that of “water floating a moving boat.” What exactly is the classical image? I think there are at least three choices: a still boat that is floating in still water, water flowing downstream, and a moving boat floating through still water. Is the last image in the classics; and if so, what difference does it make that the boat is moving?
Wushuer, I have no experience practicing atop cliffs or on thin river ice, but I have practiced quite often on frost/ice. For various reasons, I have often practiced outside before dawn in a location without enough light to view the quality of the surface. Only when the sun would rise during my practice could I then tell that I had been practicing on an iced over surface.
One of the reasons that I gave up my old way of practicing was that it felt very dangerous to me on slippery surfaces, whereas the new way greatly increased my feeling of security and control. When I now have to walk on ice outside of practice, this is now the method I use. I actually put this to an unplanned test, when I once found myself, out of sheer idiocy and obstinacy, carrying a sleeping child up and down a narrow waterfall trail that was covered with slippery rocks beside potentially fatal drop-offs. Because of fatigue, I had to use both my arms to carry the child. I was petrified of slipping even once, since several hundred yards of the steep trail had no railings and no real space to land safely, even if I was lucky enough not to slip directly over the edge. The urge to survive and protect has a wonderful way of clarifying the mind and putting aside worries about theory.
Wushuer, during one brief period, I used to do form with the image that I was standing and stepping on a surface as unstable and tricky as a windsurfer or a canoe. This focused me not only on precise balance, but the ability to be able to change to match the unpredictable effects of shifting “wind,” “waves,” and “passengers.” I found it impossible to maintain any stiffness in the legs with this image, since it incorporates the utmost necessity for continuously updating one’s balance to match changing circumstances. There is no time when you can say to yourself that you have reached a permanently stable posture and can “rest.” I no longer use this image, since I prefer to focus on other things.