Perhaps you have seen talk of new research recently into the gene ACTN3. Basically, you can be RR, RX, or XX. And evidence shows that the more R's the better when it comes to excelling in power or speed sports.
On Slate, William Saletan investigates what we know about this gene, compared to what we know about the role race plays in determining success in such sports.
You really should read the whole thing before reacting. Interesting stuff.
One thing we learn is that different groups have the optimal-for-power-sports RR setting at different rates. Africans have a significant advantage over other groups -- even over African Americans, but even more so over Asians and whites.
But I did want to quote a section that was particularly relevant to the NBA:
So, yes, all other things being equal, you can expect this gene to cause Africans and African-Americans to be disproportionately represented at the highest levels of speed and power sports. And you can expect the opposite for Asians. But contrary to Freiboden's claim, you can't expect what we actually find in, say, basketball. Five years ago, 77 percent of NBA players were black; only 21 percent were white. According to a study reported last year, black players earned 83 percent of the league's court time. Now contrast that with genetic and population data. Compared to whites, black Americans aren't even twice as likely to be RR, and they're more than half as likely to be XX. Furthermore, among American men aged 20 to 35, there are about five times as many whites as blacks. In sum, blacks are about twice as dominant in the NBA as ACTN3 alone would predict. Something else must be going on: culture, resources, differential treatment, other genes ... you name it.
Basketball has lots of confounding factors. It favors height, stamina, and court vision in addition to speed. So let's look at a sport where explosive force alone is decisive: sprinting. Several years ago, Jon Entine, the author of Taboo, summarized the data:
There are no sprinters of note from Asia, even with more than 50 percent of the world's population, a Confucian and Tao tradition of discipline, and an authoritarian sports system in place in the most populous country, China. No white sprinter can be found on the list of 100-meter sprinters; the best time by a white, 10 seconds, ranks more than 200th on the all-time list. ... All of the 32 finalists in the last four Olympic men's 100-meter races are of West African descent. The likelihood of that happening based on population numbers alone-blacks from that region, now living around the globe, represent approximately 8 percent of the world's population-is 0.0000000000000000000000000000000001 percent.