In a sprint, if you don’t have perfect form, you’re doomed. The ultra distance forgives injury, fatigue, bad form, and illness. A bear with determination will defeat a dreamy gazelle every time.

Running efficiently demands good technique, and running efficiently for 100 miles demands great technique. But the wonderful paradox of running is that getting started requires no technique. None at all. If you want to become...

[Running] is a hard, simple calculus: Run until you can’t run anymore. Then run some more. Find a new source of energy and will. Then run even faster.