Is running enough?
I have to go with Bryan. Running isn't enough if you want muscles, but do not forget to run now and then. Running is a great way to "keep your body going". It's what people are meant to do.
A couple years ago i was running between 30-50 miles a week. They didnt get any bigger but they wer hard as a rock. Now if i can get the rest of my body like that id b shittibg in tall cotton!