From Gina Kolata's The Bicycling Paradox: Fit Doesn’t Have to Mean Thin:
“When I first got into cycling, I would see cyclists and say, ‘O.K., that’s not what I perceive a cyclist to be,’ ” said Michael Berry, an exercise physiologist at Wake Forest University. Dr. Berry had been a competitive runner, and he thought good cyclists would look like good runners — rail-thin and young.I know just what she means. (I go really fast downhill.)
But, Dr. Berry added, “I quickly learned that when I was riding with someone with a 36-inch waist, I could be looking at the back of their waist when they rode away from me.”
He came to realize, he said, that cycling is a lot more forgiving of body type and age than running. The best cyclists going up hills are those with the best weight-to-strength ratio, which generally means being thin and strong. But heavier cyclists go faster downhill. And being light does not help much on flat roads.