If you aint cheatin you aint tryin

depends.

basketball, im always cheating or at least trying to. soccer, im always "cheating" (pulling shirts, being annoying as frick).

golf, youre just a douche if you blatantly cheat (i give myself a few too many non scored mulligans on occasion but ill readily admit to that, and wouldnt do it if i had a bet going).

it depends i think you can cheat and get away with it in every sport. but in baseball i hate when people cheat

In the context in which it is usually used, it's a stupid saying.