this is part of his bio from wikipedia:
"Nearing the end of the cross country season, Karnazes decided to join the track team. The track team coach, however, was Mr. Bilderback, an abrasive, domineering person who tended to talk down to his students. On the first day of practice, Karnazes ran a series of time trials for Bilderback in which tension erupted between the two in regards to running techniques, split times, and stride. Karnazes suggested that he didn’t need to have his split times yelled out to him. Bilderback asked "But if you don’t know what your split times are, how do you pace yourself?" To this, Karnazes replied "I run with my heart." Bilderback responded with gales of laughter. Karnazes states that he "wanted to punch the bastard" but instead walked off the track and hung up his shoes. Karnazes didn’t run again for fifteen years."