the fact that you are asking that tells me 1 of 2 things is correct:
1 - you are one of those people who only do cardio, too scared to venture near anything that resembles resistance
2 - you are a.... well, we know that one is correct anyway, so both must be right!
If you had seen the size of me you would agree that i dont need any more muscle, just toning, for which i need lots of cardio and then slight resistance afterwards.