i find that when i keep my chin tucked for som reason i have 2x more umph in my straight punches, Ne1 else? if u havnt payed attention try it chin up, then chin down tell me whatchu think

I don't stick my chin up until I'm back in my corner, sitting down. :boxing:

i no what ya mean with more umph !! i think its because ya all tucked in and an u can jus explode outa yaself,may sound stupid, but i no what ya mean sometimes i feel it

You're right.

You need good boxing posture to throw good punches. If keeping your chin down improves your posture then do it. And it's not a bad way of reducing the chances of getting knocked out. Most knockouts come from a hit to the chin.