Black people run faster because they are descended from slaves?

Sometimes, when one tries to come up with a ridiculous title, it turns out that you can't out ridicule reality. As a case in point, check out this "commentary" on black athletes from the BBC:

According to the commentator in this clip, black people are good at running because slavery exerted an evolutionary pressure on them that made them faster runners. This is a good example of a Non Sequitur and a Post Hoc fallacy combined with a bit of straw manning. The straw manning comes from the misrepresentation of evolutionary theory and the ideas of eugenics. The commentator in question clearly doesn't have a very good grasp of this topic and uses a very cursory analyis of evolutionary theory to develop his points.

The non sequitur arises in that his conclusion just does not follow from his premise. The reconstructed argument seems to be as follows:

1. Evolution proceeds by natural selection and survival of the fittest.
2. West Africans were slaves and were subject to enormous evolutionary pressure such that only the fittest West Africans survived the slave passage and made it to the Americas.
3. All successful (in terms of Gold medals and world records) runners are of West African descent.
4. Therefore, their success is due to their descent from slaves.

It should also be clear that this is a post hoc fallacy in that the commentator is assuming a causal relation between slave ancestry and skill at running, when there is, at best, a correlation. There are likely a variety of other factors at work here besides mere descent from slaves. Furthermore, as PZ Meyers notes,  the evolutionary story doesn't even make sense:

…because, obviously, being able to survive shackling in a slave ship and a lifetime of menial stoop labor in the cotton fields clearly selects for genes of benefit in short foot races.

If anything, it would seem that slavery would select against speed over short distances as the last thing a slave owner would want is for his slaves to be able to run away!