lol youll be able to take body shots easier if u had bigger lats, but i dont see how it could affect your jabs if you're not at a body builders level, youd need at least 5-6 years of pro body building until you can get lats that would set your jabs astray.

lol man, Tyson and Roy Jones Jr done pull ups that i know 100%, and im very sure a lot of other boxers do it as well.