It's a long way down. We're parked at the edge of the Rift Valley, looking out over the vast, faded mass of land stretched out below. In the back of the van are about 10 Kenyan runners, including David Barmasai, who a few months ago won the Dubai marathon (the most handsomely remunerated race in the world) and is part of the Kenyan team for the upcoming world championships.
The driver starts the engine and we bump along the uneven dirt road winding its way down into the valley. Far below, small, cone-shaped mountains poke up like grassy knolls.