Here's a NY Times article on body shape and age with regards to biking vs running. It reflects on a discussion here a month or so ago.
Interesting, although I can assure you that the article understates the part about the body types of those who race. Pro cyclists typically have body fat numbers lower than runners due to the very long races. I was usually racing at 3% (about where I am now), and that was about average for amatuers. As a pro, I was one of the "big" guys. Yet, I go to running races now and I'm one of the thinnest people there.
Yeah, the article's focus was more on 'very good' experienced riders; but a major step below racers.
FWIW, Andy Hamsten has always been my favorite pro cyclist. He really is as affable in person as he comes off in articles. Absolutely non-elitist. He'll talk to just about anybody and he's really supportive of people of all levels. Pretty rare in someone who's won the second biggest race in the world.