Why Swimmers Spit Water: A Simple Explanation

Question
While watching the trials and olympics we noticed that most of the swimmers put a handful of water in their mouths, swished it around and spit it back out. We are not sure if they spit it on deck or back into the pool. Why would they do this?

Answer
Miles--
Believe it or not even the worlds best get a small case of nervousness and this causes dry mouths.  The reason they put a handful of water in their mouth is to get the moisture going.  Most of the time they spit the water on the pool deck.
Hope this helps.
George