Imagine the scene, Indian Jones scrabbling up a rockside. He seeks out hand and footholds which crumble in his fingers but eventually finds a foothold which can support and give equal and opposite force to what he exerts in order to advance up. With a great push he braces his pelvis, extends and connects a chain of muscles from his toes to the tip of his fingers which propels him to safety.
What's that got to do with wing chun? Imagine someone throws a punch at you. You raise a tan sau, make contact and using your structure are able to connect a muscular chain from you arm to your feet which create what feels like an impenetrable obstruction. The problem is that the other guy is not an inanimate rock face. If he is trained he will sense your strength, and quickly move around it. If he is stronger than you (attackers usually are) he might just smash straight through as he will have the advantage of momentum in his strike.
With most wing chun training you are dealing with the scenario of the skilled opponent looking to move around force. Both are trained to turn power on and off; where you find the opponent offers no resistance you power up and attack. The problem with this on/off method is that when you are 'on' you provide a platform for the opponent to feel your strength and where it comes from. It might be a flexing of the hip, push off from the toes or just a locked up shoulder. Show where you are strong and it only takes a big enough lever to have you lifted off your feet or at least have you arm moved out of the way. The thug on the street is not sensitive to minute flicks of the wrist, but they will throw big blows which will rock your alignment to its core.
A challenge in training our wing chun is that the type of alignment you are seeking is not what you think it is and you cannot use the signals which you would normally rely on. If you feel strong, it is because your muscles are giving feedback to achieve this sensation and all you are feeling is tension. It might be strong, but in only one direction based on a crude alignment. The alignment we are looking for has to come from using the cohesive mass of you body directed to the body of you opponent, which takes into account a lot more than pointing your wrist and elbow into the centre line.
This might sound difficult, but the process is relatively simple to demonstrate and to pass on by a patient instructor. However it can be frustrating for a learner as they do not receive the physical feedback of a tensed muscle which they expect and which they want to rely on. The usual comments when someone gets it are 'how did that happen, I did not feel anything' or 'I did not do anything'. The answer to that is it is exactly how it is supposed to be, by sharing the load through your body and the ground the impact is not taken by local joints and you hardly feel a thing (ideally). Once you get the hang of this, it becomes more a matter of awareness, which as ever takes us back the reason for practicing the sil lim tao form to get us in touch with our bodies. Don't believe anyone who tells you that you need to ignore the force, it is how you deal with force that matters.
As I said it is not that easy, there are no set positions and no perfect alignment. But.. there is one constant which you can rely on and that is the state of relaxation you have been seeking to achieve in practicing the forms and within the partner exercises. So in the end it is that one mental and physical state you have developed and can be depended on, which should provide support for all of the movements/techniques you use.
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