your body becomes good at what you ask it to do....
SO... if from an early age you are running and sprinting.....
that is what you become VERY good at...
and if you grow up in a country where you are too poor to afford toy's and don't watch telly..... what do you do with your time?
RUN around with your mates... playing had/catch/tag ect.
as i said... it has MORE to do with social demographics than anything else.
tho why there are not so many asian sprinters could probably have something to do with the fact that on the most part they have short legs
your skeleton is THE only part of your body that does not adapt.
everything...from internal organs to muscles to skin to eye's to hair to the brain is fully ADAPTABLE
its kinda the reason why we are the top dog on this planet...that and those nifty thumbs of ours.
if black men are predisposed to being more athletic why has the worlds strongest man alway's so far been white?
if asian pearl divers are genetically predisposed why is the world champion free diver white?
the reasons for the sterotypes you talk of...as i have stated are related to sociology.... NOT biology.
that much is fact.
it's not MY fact... its just science fact.
and for your info... plenty of white atheletes can run 100m in under 10 seconds...
and the first person to run a mile in under 4 minutes was white...not from east africa.
as i said it's sociology...
NOT biology.