Another question I wanted to ask, how does "IP" effect the ability to jump? Can learning "IP" improve jumping ability?
I quite honestly can't give you a "correct" answer, since by and large you don't want to push off the ground with IS and its not something I have trained in particular. That being said, you can slam the dantien off the ground to bounce your weight to power a strike, but I've never seen anyone use a "bounce" jin to dunk a basketball.
Likewise through breath training, you can figure out how to do leg presses via breath power as a conditioning exercise. I'm speculating that you could do some sort of breath powered jump, but given that I can only do maybe 50-60lbs via a breath powered leg press (I can only leg press 500lbs or so last time I tried without using IS), so I lack the skill/conditioning to power a jump without using the leg muscles.
Now I do know people on the IS seminar circuit who can do breath powered leg presses of a couple hundred kilograms, so I'm guessing they might be able to use that to jump. At the very least, I think it would help because your gain more sensitivity of the legs, hips, lower core and development of those muscles which could be used to power a jump , but I have no evidence to offer. Its not a demo I've seen online or at a seminar.