you obviously never paid much attention to cycling , weightlifting sprinting just fro a doping pov . As for football when is the last time you watched a pro game without someone "diving" .All athletes want to win, that's their main driving force. Depending on the level, of course, there won't be many who are in it just to take part. But tbf, only a very small percentage are prepared to cheat. It's why there's uproar when a 'winner' has been found to be doping.
