When Tom Foreman was young, he was a competitive runner in all the races he entered. And he barely trained for these races.
But he stopped running for years. Then his daughter asked him to help her train for a marathon. He went on from that to run four half-marathons, three full marathons, and a 50 mile ultramarathon in the space of a year. He documented his experience with a book titled, My Year of Running Dangerously.
Since that year, he has gone on to run marathons and ultramarathons, including the Boston Marathon. And he has the mindset to keep going as far as he can in his running journey.