<font face="Verdana, Arial" size="2">I don't know why nobody is willing to answer your request for practical supplementary exercises. I suspect I am about to find out though.</font>
Who can resist such a challenge?
I suppose the easy answer to the question is that the form and push hands drills are themselves the supplementary exercises that help to understand the principles described in the classics. One approach is to break down the form in order to understand how it embodies the principles.
I do not know what theory of teaching that Yang Zhenduo and Yang Jun use, but what I project onto their teach is the following. The essence of Taijiquan is based on principles and is formless. In other words, the important part is internal. Because of this, there is no way to teach or learn merely by external patterns and imitation. To remedy this, they seem always to teach some theory first, before doing anything else.
The problem with teaching theory first is that it is difficult to understand deep theory without practical experience. To remedy this, they teach standard patterns that have two distinct teaching purposes. First, the patterns give examples of how principle and theory should be externalized in various situations. By studying these, you can come to understand the theory better.
Once you reach a certain level of mastery in the standard patterns, one can revisit the theory directly and peel back a layer of the “onion” to understand the theory and the principles more clearly. With this new understanding, you can refine the standard patterns and begin to use them for the second purpose. This purpose is to provide a safe framework within which to actually use the principles and theories. In other words, they provide a medium for exploring and practicing the principles in the same way that water provides a medium within which to swim. To swim, you need both certain motions and water. To do Taijiquan, you need both external form and internal principle.
I think the difficulty of such a journey is one of the reasons why personal teaching and long practice are both stressed so strongly. Without approaching the goal from various angles and without using a sustained attack, it is hard to achieve much.
Despite our best efforts, this journey still proves frustrating and often elusive. A particular worry is whether we properly understand the principles that guide our first step on the “thousand-mile journey.” If this step is aimed in the wrong direction, we risk missing our destination by a huge amount. I think that this is the context in which the question posed on this thread becomes most pressing.
I think that every practitioner and every teacher has his or her own way of visualizing the basic principles. Learning and teaching styles differ, and I doubt that that the same exercises or practical tips will work for the same people. For me, the best ones are the ones that relate most closely to the form and the push hands drills. Here are a few of mine.
“Loosen up the waist”
If you know the vertical four-hand circle, try doing it on your knees with your knees slightly overlapping those of your partner. From this position, it is impossible to mistake ankle and knee movement for waist movement. Do not, however, do a lot of this to start off, because the newness of the movement may put demands on your lower back muscles that they cannot tolerate.
“Sink the shoulders and droop the elbows”
Assume the best push posture you can and have your partner push on the outside edge of your palms in an effort to collapse your arms. If he or she succeeds, your elbows are probably pointed toward the outside. If he or she does not succeed or merely pushes you in a slide along the floor, this is good. To understand what is bad, try this variation. Assume the same posture, but flair both elbows so that they both point horizontally toward the outside. In this position, your partner should be able to collapse your arms. The difference in the feel of both postures should be dramatic.
As with anything, there are downsides to this exercise. One is that one can achieve arms that will not collapse by locking the elbows and making the palms flat, as if pushing on a wall. Although this is a strong position, it is strong in only one specific vector and can easily be undone with only a slight change in the direction the force is applied. If you have tendency toward this, try doing the same exercise but with a pronounced bend in the elbows, you should again experience dramatic differences according to whether the elbows are sinking the Qi downward or scattering it to the sides.
Another drawback is that people can think that the elbows must always point straight down. To peel back one layer, consider where the elbows begin close to the body in the Push Posture of the form. If one maintains space under the armpits, it is impossible for the elbows to point straight downward. Also notice that the circular push in the horizontal one-hand push hand drill also requires somewhat different elbow placement. Although you always want to sink your Qi, you need to mobilize your power in more ways than simply up and down.
To peel back another layer, consider the right elbow in Fan through the Back. It actually points somewhat upward; but even here, a small difference in how the shoulder is held can completely separate the power in the shoulder from the movement of the waist. It should feel as if the shoulder is down enough so that the twisting of the body can give pulling strength to the right arm.
To peel back yet another layer, consider Brush Left Knee, Cloud Hands, or Cross Hands. All of these postures have movements where an arm performs a vertical circling motion. The problem is that having the elbows down on the descending portion of the circle must necessarily be different from how they will be on the ascending portion. The changeover point requires motion in both the elbow and the shoulder that must be fairly precise.
What the Yangs teach is that power comes from loosening the joints to unify the body’s energy. In theory, nothing more is required. To feel this, try standing with the feet parallel and shoulder width. Extend both arms and make fists in what you believe is a loose/relaxed fashion. Without bending either wrist, elbow, or shoulder, you should be able to punch very hard with either fist merely by using your “loosened waist.” No local contraction of your arm muscles is necessary. The punch will travel only two or three inches, but be very powerful. Again, be gentle with this if you have not trained in this kind of way before.
If your arms are too limp, no unification will take place and your waist power will be of no use. If your arms are too stiff, this will interfere with the flow of power. If you have difficulty in keeping from bending your elbows or shoulders, this is because your mind is thinking of a punch as a local movement that requires local storage of Jin. You are not recognizing or making use of the Jin already stored in your waist and torso.
When I do this exercise correctly, I have zero feeling of squeezing the muscles in my arms; on the other hand, holding my fingers in a fist shape requires some muscular exertion in my forearms. If I squeeze my fists tightly, the tightness travels up from forearms into my upper arms and then interferes with the free motion of my shoulder. For every quarter inch that one fist moves forward, the other fist moves backward. The movement of both arms is organically linked with no effort on my part. There is no sense of coordinating the arms, since they are simply linked through the back.
By the way, I deliberately chose a “power” example to illustrate the principle of “loosening/relaxing” to disassociate it from notions of effortlessness. This too has a place within the theory, but in my opinion it is not correct for the Yangs teaching methods to see “loosening/relaxation” as directly related to the level of muscle use.
“Use mind intent, not force” and “hold in the chest and pull up the back”
If you find the previous exercise helpful, you will have experienced an example of how the way in which your mind relates to your body matters more than how much you squeeze the muscles in your arm. To make the exercise successful, you cannot rely simply on punching “harder,” you must first learn to apply your mind correctly. Once your apply your mind correctly, you are not constrained in the amount of power your generate. “Power” (“Jin”) is enabled by your mind intent (“Yi”), not by “force” (“Li”).
Another thing you must do is to “hold in the chest and pull up the back.” Try doing the exercise with your chest puffed out and your shoulders drawn back. You will see that it simply does not work, since the arms are no longer unified with the torso, the waist, and each other.
Do these suggestions make sense or prove useful in illustrating the theory? If they do, I would suggest actually abandoning them, since I do not consider them training methods, but only ways of illustrating certain points. To train the principles, I would suggest looking for the same feelings in various postures of the form and push hands drills. They should be everywhere, but sometimes in disguised form. Sometimes they are clearer in one posture than in another.
If these suggestions make no sense or do not prove useful, I would suggest that you challenge my understanding with some friendly prodding and questioning. I would love to learn more and be corrected. On the other hand, if you wonder whether I may be on to something, but cannot get it to work for you, describe what doesn’t work or ask about whatever is not clear.