BNK!-rrr. BNK!-rrr. BNK!-rrr.
The first 'BNK!' is only the sound that my reverse snap punch makes when hitting the makiwara (actually it's not a real makiwara, but a cheapo wall-mounted striking target) in my garage.
The second sound 'rrr'? Why, that's only the sound of the garage as my punch vibrates its single brick walls.
I've posted on this before, but working with this particular punch is one of the best things to happen to me in my black belt years. It's how I'd like everything I am practicing to proceed - more power through technique and through less effort. The reverse snap punch indeed starts with the knees, legs and the hips. The hip twist movement is then transmitted through solid core muscle tension and tight lats. The lats hold the upper extremities close to the upper body in order to benefit from the increased body mass. Letting the punching arm leave the body and have freedom of motion only reduces striking power as it is driven by shoulder, pectoralis muscles, and arm muscles.
I have not yet installed a real makiwara. Even the martial arts supply shop guy thought I was half-mad throwing any sort of power onto the wall-mounted striking post he sold me. So I really try to restrain myself to keep those arthritic knuckles at bay! But this punch rocks, baby!