plus rep that.
there is indeed a bounceback or wave effect per the third law of motion. this compressive force is primary for generating force over a short space. 'sink' or 'root' are terms that refer to this adjustment.
speed and contact interval are also major determinants of 'wattage'. too slow and all you get is a push.
regards.
Leung Ting taught us pretty much the same thing regarding the “bounceback” and timing. Essentially, there are
two stages to the one-inch punch. The first is the hard impact of the “bottom-fist” or lower three knuckles. The second stage is to snap the wrist upward, driving the bottom knuckle sharply forward another inch or so. These are aplied in very close sequence. If you let the interval between the two lag a bit, allowing the “bounceback” to complete itself and then add the second part of the punch, the effect is to accelerate your opponent’s entire body backwards without hurting him too much. This is the demo version that can be safely executed with just a phonebook for padding.
The second way of applying the inch-punch is to shorten the interval between the initial impact and the following wrist snap, so that the second thrusts impacts exactly as the first one reaches maximum penetration and the “bounceback” begins. You effectvely collide with, and
thrust through the “bounceback”. This does
not make for a good demonstration, since your opponent’s body does not move backward. Instead the punch penetrates deeply, and your opponent usually crumples to the ground in pain. I have felt this done very lightly, and it hurts like hell, totally knocking the wind out of you, or worse. But, to a bystander, it looks like nothing happened. The effect of the first version of the punch is a bit like butting a watermelon with the fat end of a baseball bat. It knocks the melon backward, bruising it a bit. That’s all. The second version is like jabbing the melon just as hard with the point of a screwdriver. The melon doesn’t move, but you go right through it.
Now to respond to Jarrod,
hell yes this kind of short-power has combat applications. Any way you can get useful punching power in a short distance without having to draw way back and telegraph your intent, that's gotta be a good thing to stick in your toolbox. Different systems may have some different ways of generating this power. I learned a different approach studying Escrima with Rene Latosa, for example. But regardless, if it works, it's good. Just my dos centavos.