Strength of the mind
If the body tires, the brain pushes,. If the impossible is to be achieved, the mind must be convinced. If you start believing, you are a step closer to winning.
The star of the 2008 Olympics so far has got to be Micheal Phelps. 8 Gold medals, 8 World Records in swimming.
The dedication he gives to swimming: "Eat, Sleep, Swim". Kudos.