Can someone please explain

CyclingNewbie said:

I was watching the olympics sprint cycling the other day.

Why is it the competitors ride a lap or so real slow just looking at each other. Why not go hard the whole way? what's the tactics behind this?

The race is actually for the full 3 (or 4) laps, timed for the final 200m.
Nothing is stopping a rider attacking straight away and trying to hold off an opponent to the line.
This could, however, prove to be a massive tactical blunder, as the rider in 2nd place is using 30% less energy than the rider leading and could presumably come around in the closing stages to win, so you won't see this too often. Some riders prefer to lead out, some prefer to come from behind so this is where the tactical riding of the early laps comes in.

Read this track racing FAQ

http://www.cyclingnews.com/track/?id=trackoverview00

Perhaps I'm misunderstanding the race, but going out fast at the start will tire you out so the final 200 meter will be slow and if that 200 m time is what counts you don't want to just crank it at the start. In fact you would want to go quite slow. Is it the first rider to cross the line that counts, or the time over the 200 m? i.e, you could win by having the faster 200 m even though you didn't cross the line first?!

bikeguy2 said:

Perhaps I'm misunderstanding the race, but going out fast at the start will tire you out so the final 200 meter will be slow and if that 200 m time is what counts you don't want to just crank it at the start. In fact you would want to go quite slow. Is it the first rider to cross the line that counts, or the time over the 200 m? i.e, you could win by having the faster 200 m even though you didn't cross the line first?!

the time for the 200m only matters when qualifying.

From then on, it's first man home wins, whether he rides a 10.5 or a 13.