REDDING, Calif. — Sprinting seven miles down a 9,000-foot mountain and then running back up to do it again may not appeal to even the most self-punishing of athletes, but Ryan Hall believes it is the kind of “experimental workout” that transformed him into the fastest American distance runner in history.
It is also the kind of extreme training that is now causing him to abruptly retire, two decades into an audacious career that produced national milestones — his time of 2 hours 4 minutes 58 seconds at the 2011 Boston Marathon is by far the fastest for an American runner — but never a victory in a major race.