Sprint vs. Distance

In swimming, how is it that one can excel in both sprints and long distance? Is it because the distance games in swimming are only "relatively" distance games but are not really distance games from a physiologic perspective? In the world of tracks, for example, an athlete cannot excel at both sprints and distance. Even the athletes from the two areas look different - much leaner for the distance runners and muscular for the sprinters. I am wondering about this because whether I should focus on either the sprint or the distance as I plan to participate in the masters meet, or whether I don't have to sacrifice one for the other.