I can dispute it. Not to say this entirely incorrect its just far too simplistic an explanation.
Its a bit like an extended family. Some family might have "tall people" in
them. Likewise in Africa depending on the enviroment over the course of many
years various genetic traits have developed. In flatter eastern part of Africa
"the gold coast" from which the slaves were taken it seems that it was
beneficial to be "fast".
However in other parts of Africa like say Kenya the western part of africa
have extreme amounts of slow twitch muscle fiber - which is more suited to the
hilly enviroment.
diversity that is present in Africa. Nonetheless its not a coincidence that say
Northern European men DOMINATE the strong man competitions and Olympic
weightlifting events. They have the right genetic backarounds.
But genetics DO play a huge role and its quite clear that the East African
genetic profile is well suited to a number of popular sports namely Basketball
and Football.
Its not so hot for say bike riding or swimming - but who really cares about those sports.