Heng Chuan is absolutely fascinating internally. Watch the Large Style demo of Heng Chuan. This is Liu’s version and the only one I pay attention to. At 33 secs, Bruce starts a series coming at the camera. Notice the stomp at the end of each technique.
Although it isn’t as pronounced in Heng Chuan as in some of the other fists, the internal effect is greatest in Heng Chuan. I personally found this in Heng Chuan and then could integrate it into the other fists. So, what’s happening?
I use the stomp as a weight shift that serves multiple purposes. 1) It is both the end of the fist and the beginning of the next. 2) I use it to shift my weight. Notice that Bruce has to shift his weight to do the initial cross step because his weight is stuck on the leg that needs to be picked up. 3) Produce a second strike going across the body. If you push off the opposite leg into the stomping leg, you get a second strike that continues the movement to the side. This is brilliant and sets the weight in the appropriate leg to allow the cross step without another shift. This is a little hidden by the transition from the end of one fist to the beginning of the next. Remember you have already hit with the fist coming out. This shift allows you to continue the strike on a very odd angle.
So, I’m just saying that the stomp encodes this shift. I can’t describe all of the internal flows, but I will mention that one interpretation of the crossing fist is this flow from one side to the other. I believe this is key to balancing the internal organs.