If her boobs were that big in real life she'd fall over... just sayin'
but then again bra's also don't work that way and there is no way her jacket would stay perfectly covering half of her breast- they'd just completely fall out the minute she moved but fortunately cartoons don't fallow the same laws of physics and gravity. And boy do males like to defy the laws of physics and gravity when boobs are involved. lol
Well no offense but just cause you're a woman doesn't mean you know more about proportions and physical ailments. If all big breasts caused serious back problems there would be a lot more breast reductions and virtually no big breasts to be found. I just think it's lame, every time some artist draws a woman with big breasts, people start yapping about back problems. Big breasts are a natural thing and they don't have to cause problems, just in extreme situations. Also about the exercises, you can train your muscles in the stomach and in the back so they can support more weight, it just takes a lot of work.