The fastest Olympic sprint was Usain Bolt’s 100 meters at the London Games, averaging more than 23 miles per hour for 9.63 seconds. Marathoners, who run for two hours, top out around half of Bolt’s speed.
The 100-meter and the marathon are at either end of the Olympic spectrum of running races. The sprints (100, 200 and 400 meters) are strictly about power and mechanics. The endurance races (1,500, 5,000 and 10,000 meters and the marathon) are all about the supply and demand of energy. The 800-meter race, while just two laps around the track, sits between them, the painful middle ground between a pure sprint and pure endurance.