According to an article in the on-line version of The New York Times today (“Bigger is Better, Except When It’s Not”), world-class rowers usually are big. Swimmers are tall. Distance runners are small and light. It’s all according to the rules of physics, exercise researchers say.
Previously I speculated that in a high-tech future world, children and their parents will be able to choose what sports the child is most likely to excel in based on hard scientific evidence (see the Directions in Science feature in Human Biology 5th ed., p. 132). Apparently some of the evidence is now known. But this does not mean that size, body form, and muscle biochemistry are all that matter. As the experience of Lance Armstrong has shown, good training and desire also count for something, too. Unless you aspire to be the best in the world, go out and do what you enjoy!