My lift days are Monday, Wednesday, Friday, and Saturday. I was wondering if doing some cardio on my off days will be ok (Tuesday, Thursday, Sunday). I plan on doing 30 mins on an elliptical, and some speed ladder work. I might throw in some plyometrics also. I've been hearing some people say that too much cardio is bad for building muscle, but for a guy who wants to build, but also burn fat, is this a good thing to do?