hello, recently i watched a video of a chinese master of hsing-i talk about fighting. he said that in one of his fights from younger years,he used the crushing fist form,and hit the guy with chi from his lungs which only knocked his opponent out. the old master ( probably in his 70s) said had he used chi from his kidneys that his opponent would have died. what does all this mean ? i thought that power in a strike came from having a very strong core,back,and legs. so that is how i have trained. but after hearing this, i am confused. could someone please tell me what the old master was saying ?

respectfully,peter