From the time the ancient Greek runner Pheidippides ran from Marathon to Athens to announce the Greeks’ victory in the Battle of Marathon, humans have had a compelling interest in endurance running. With 500 marathons in the U.S. each year, and more than half a million people running them, the marathon has become a big deal. Chasing Pheidippides: Marathon Training 101 provides a physiological overview of the marathon and how to train for it using a variety of workouts. (71 min)