I play football (soccer) 2 or 3 times a week, and when I'm not doing that, I ride my bike because the two activities seem to use completely different muscles. I remember last year, when I came back from a 6 week bike tour, I played football my second day back thinking I was top-fit. After that game, my legs were screaming at me! It was agony. Based on that experience, I would say biking does nothing for running muscles.
