I posted that a few days ago man!
Well, for a lot of the "push" sports like bobsleigh, skeleton, and luge generally they don't grow up doing the sport. They play other sports, whether track and field or football, and then end up going in to those push sports. That's what happens with most of Canada's bobsleigh team, they wait for certain athletes to finish up their previous careers and then poach them:
Bobsleigh Canadas strategy of recruiting from other sports is paying off - Editor's Picks, Life, Sports - Macleans.ca
The Canadian who won skeleton in 2010 (and was running around the Olympic village immediately after chugging a pitcher of beer) didn't even start doing it until he was 24:
Jon Montgomery - Wikipedia, the free encyclopedia
He's basically said "I wanted to win an Olympic medal, didn't really know how, and then stumbled across this goofy sport by accident and here I am."