"So how did so many of these Americans run so fast from 1979 to 1989? Obviously there are many factors to consider but from what I’ve read and researched, these runners would 'run by feel,' and often did not adhere to a rigid set daily schedule, or record every split second using a GPS or Garmin-type device. Sure, they ran everyday but they monitored their bodies and performance based on effort level and feel."
This has prompted a spirited discussion over at the Minimalist google group. (Harry cross-posts a lot of his stuff.)