That makes them so good at running? Just watching the athletics and 7 out of 8 in the 100m final are black (top 3 all jamaican) is there something in physiology?
When I was an athletics coach it emerged that black athletes of certain origins (not the Mo Farah's of this world) possessed a much higher percentage of 'red twitch' muscle than white athletes. There are also different bodily characteristics, such as more powerfully developed gluteus maximus. This gives them the advantage in speed/power events.
At the time, one fairly high-up coach (who quite innocently pointed out these facts) was effectively sacked.
back in the days when the West Indies were the top cricket team thanks in part to an endless line of ferocious fast bowlers, I recall reading a claim that they somehow had extra super spines because of genetics.
Then the endless line ended and all of a sudden genetics must have just stopped happening. Funny thing, DNA.
This question has been only partially answered for decades and it has nothingto do with the physiology but everything to do with the anatomy.
The Achilles tendon is an important muscle used in sprinting and the angle at which it is inserted into the talus ( ankle bone) is fundamental in sprinting. That angle tends to be large in Negros compared to other races and may, just may, give them an advantage in the sprint events.