Are Kenyan(and other east africans)primarily the best runners on earth? Yes
Do they cheat? no more or less then anybody else
Do they train harder? NO MORE OR LESS THEN ANYBODY ELSE!
I feel that Kenyans are naturally great runners (along with Ugandans, Ethiopians, and most east Africans) because they live at an optimal training altitude with optimal temperatures for year round training. they also have high motivation (i.e. winning major race is a method of survival for their family).
they also spend allot more time on there feet (mostly barefooted) running and walking to school and town and about the village. this is like training in disguise from a young age. also children start working at a younger age which has been known to physically mature a person quicker.
Why are Asians' eyes squinted?
because they have adapted over generations and generations to adapt to high wind speeds in the Eastern Asian region.
Why are Kenyans supreme endurance athletes? Because they have adapted that way over generations and generations. There given lifestyle combine with the region has made this group of people great distance runners.
just my take! what do you think?