(Bloomberg Businessweek) — The town of Iten, perched on an escarpment in western Kenya a mile and a half above sea level, holds an elevated place in the sports world as a training ground for elite long-distance runners. Olympians Lornah Kiplagat, Mary Keitany and Sylvia Kibet have all logged hours on the dirt roads that wind through the surrounding fields and forests. The world’s fastest marathoner, Eliud Kipchoge, is one of eight a…