I love working out, but I don't like to get too big....

Are you someone who doesn't just gain extra muscle when working out, but also extra bulk?

A lot of long distance runners complain of the same thing. If you are looking for lean muscle mass, then you need to find an exercise that will burn calories while you rest.

One thing you can do is interval training. You can do this while you run, do the elliptical, jump rope or bicycle. It burns those calories up to 5 hours after you complete the exercise. Whereas, if you do steady running, you're likely to stop burning calories once you step off the treadmill.