By 2010, Iten, a small town perched at 2,400 metres in the Rift Valley highlands, had become one of the most famous training venues in the world. Runners from Japan, the United Kingdom, the United States, Australia and dozens of other countries were flying to Kenya to train at altitude alongside Kenyan runners. They shared camps, tracks and the thin air that had produced so many world champions. The knowledge that Kenyan runners possessed about training, diet, pacing and mental endurance was being exported to the world in person, one visiting runner at a time.