More races mean more athletic children think of pursuing long distance running, especially in places like South America and China, where the sport still has significant room to grow.

WSJ: Breaking the Two-Hour Marathon Barrier

Unseen, though, was another opponent: Prefontaine, whose presence decades after his death on May 30, 1975, at the age of 24, has loomed large over long distance running in the United States.

CNN: Chasing Prefontaine: The run for a record

Fans who follow long-distance running are already familiar with Kenya's legendary success in the sport.

CNN: 'Kenyans' leads list of great running reads