That's a genetic advantage inherent within a specific tribe(Kalenjin), within a nation(Kenya) within a race(Black)... Doesn't really support your argument.Actually, thats not true. But it is easy going overboard with the discussion. Where does racism start and end?
For example check out this story about kenyan runners Why Kenyans Make Such Great Runners: A Story of Genes and Cultures
Genetic differences even advantages are not split down racial lines but rather populations. You are looking at it from a very Black and white context when it's grey area.
What is true is that one race has more genetic diversity than the other and thus these advantages are a result. Europeans don't have as much genetic diversity as African populations. There's more genetic diversity within a tribe then there is amongst whole European nations..
People from Africa have the most ancient populations and thus the diversity and variety in gene pools.