I understand that too much cardio can not only burn fat but also muscle. I do not overdue my cardio, either I run a mile or I do 30 minutes on the elliptical machine to ensure that I do not lose my upper body gains. I just recently started to work out my lower body and was wondering that if doing my cardio will affect the growth of my legs as they would not have the proper time enough to recover. Should I take a couple of days off, take one day and do a little cardio the next, should I only do some sort of cardio once a week, or should I not do cardio at all if I wish to see my legs grow? My legs are sore for 3 or so days after I work them out and I'm scared that by that putting strain on my lower body and exercising my legs again may completely screw up my lower body recovery process. What do you guys think? And is it ok to run or do 30 minutes on the elliptical machine before my leg routine?