Emil Zapotek and Willpower

"If one can stick to the training throughout the many long years, that willpower is no longer a problem. It's raining? That doesn't matter. I am tired? That's beside the point. It's simply just that I have to."
These were the words of Emil Zapotek. He was the Czechoslovakian winner of the 5000 metres, 10 000 metres and marathon at the 1952 Olympics. His achievement was a reflection of his strong will to excel. So far, he was the only person to have swept these 3 long distance races in the Olympics.
Willpower is build up over time. Emil is a good example. He probably ran everyday to maintain his stamina. I am guessing. His consistent running conditioned his body and mind. I am still guessing. Rain no longer posed a problem. Running could still be continued. Rain became insignificant. Tiredness might seep in but because the mind and body were well conditioned, It did not matter. Run, continue running. Nothing could stop him. Running became part of his life. Running became him. Just like Forrest Gump. A state of nirvana?
Why do I have to run? To keep fit? To cut down weight? To relieve stress? It doesn't matter. I just run. I enjoy the process. Running is not me and I am not running. I just run. Got it?