FILE--Members of the Serpentine swimming club emerge from the Serpentine Lake after taking part in the traditional Christmas day swimming race in Hyde Park, London, Tuesday, Dec. 25, 2007. If you are of a certain vintage, you will recall a special torture parents put their children through in summers. On stifling days at the beach or the pool, with the sun beating down and the cool water beckoning, mother after mother could be heard admonishing impatient children: “It isn't an hour yet!” Somewhere, in the far reaches of time, someone deemed it unsafe to swim for an hour after eating. But now, coaches are even encouraging Olympic swimmers to have a snack before plunging in. THE CANADIAN PRESS/AP Photo-David Azia