normally the puking comes from the amount of exertion needed when working legs. leg days use not only your leg muscles but also almost every other muscle in your body and you just tax the body so bad that you get lightheaded from all your blood rushing into your muscles and not having as much go to your brain. the strain from doing squats or really heavy leg presses will also have an impact on your internal organs because you will be also using abs and they will be pushing against your organs.sesso said:
most other muscle groups do not tax the whole body the way the legs do nor do they use up most of your blood supply when the muscles get pumped. about the only other exercise where i have been known to puke is deadlifts because it is similar to squats in that it taxes your whole body and requires an extreme amount of exertion to perform heavy lifts.
