The Kalenjin; The Athletic Tribe Of The World

It turns out that Kenyans' success may be innate. Two separate, European-led studies in a small region in western Kenya, which produces most of the race-winners, found that young men there could, with only a few months training, reliably outperform some of the West's best professional runners. In other words, they appeared to have a physical advantage that is common to their community, making it probably genetic.
The studies found significant differences in body mass index and bone structure between the Western pros and the Kenyan amateurs who had bested them. The studied Kenyans had less mass for their height, longer legs, shorter torsos, and more slender limbs. One of the researchers described the Kenyan physical differences as "bird-like, " noting that these traits would make them more efficient runners, especially over long distances.
But the athletes themselves declare that nothing comes easy in the world, hard work and dedication is what brings about change.