Here's a safe prediction: all of the athletes who line up for the final of the men's 100 metre sprint in Sydney can trace their primary ancestry to West Africa. Further, it's unlikely that any sprinter other than one with West African roots will ever again hold the unofficial title of "world's fastest human".
Remarkably, as equality of opportunity in sports has increased over the past 30 years, equality of results on the playing field has declined: elite sports are actually becoming more segregated, reflecting the differences in body type and physiology found, on average, in different populations.
What's behind this trend?
Scientists are beginning to deconstruct the mystery of human performance: the intricate relationship between population genetics - average differences between populations shaped over many thousands of years of evolution - and environment. Robert Malina, an anthropologist at Michigan State University and the editor of the American Journal of Human Biology, has studied more than 50 years of athletic performances and come to this conclusion: "Differences among athletes of elite calibre are so small that if you have a physique or the ability to fire muscle fibres more efficiently, which might be genetically based ... it might be very, very significant. The fraction of a second is the difference between the gold medal and fourth place."
Reams of studies definitively show that genetically linked, highly heritable characteristics such as skeletal structure, the distribution of muscle fibre types, reflex capabilities, metabolic efficiency, lung capacity, and the ability to use energy more efficiently are not evenly distributed among populations and cannot be explained by known environmental factors. Humans are truly diverse, biologically and culturally. Although scientists are only just starting to isolate the genetic links to those biologically based differences, it is indisputable that they exist. Each sport demands a slightly different mix of biomechanical, anaerobic and aerobic abilities, and athletes from each region of the world tend to excel in specific events. Whites of Eurasian ancestry, who have, on average, more natural upper body strength, predictably dominate weightlifting and field events such as the shot-put and hammer (whites hold 46 of the top 50 throws). Where flexibility is key, as in diving and some skating and gymnastic events, East Asians shine (hence the term "Chinese splits").
If any population has had less access to the latest in sports medicine, technology, coaching and opportunity, it's black people, especially indigenous Africans. Yet Africa is showing the most explosive growth in elite athletics. Nigeria and Cameroon are emerging as world powers in soccer, and African athletes are flooding into the elite ranks in European soccer leagues. Moreover, every major men's running world record is currently held by an athlete who traces his ancestry to Africa.
There are clear social reasons for this trend: running and soccer require relatively little equipment. But there are biological ones as well: on average, sub-Saharan Africans share a number of structural traits that provide critical advantages in most sports: low relative body fat, long legs in comparison to the rest of their bodies, and narrow hips. But while they share many characteristics, quite distinct body types have evolved in the east and west of the continent. It is athletes of primarily West African origin, including North American and Caribbean blacks, who are physiologically the world's premier speedsters and leapers.
African Americans make up about 13 per cent of the US population, but almost 90 per cent of its professional basketball players, a mirror reversal of the black/white ratio of 40 years ago, when racism restricted participation. American football has gone from virtually all-white to 70 per cent black; baseball to almost 40 per cent black.
Despite the harsh discrimination that sharply limited black participation for much of the past century, blacks of West African ancestry utterly dominate elite sprinting. The last white man to set the world record in the 100 metres was German Armin Hary, who won the Olympic gold medal in 1960 in 10.2 seconds. Today, the 200 best times - all under 10 seconds - are held by athletes of West African descent. All 32 finalists in the last four Olympic men's 100 races are of West African ancestry.
For decades, such athletes have dominated the sprints and hurdles, even holding off the assault by the drug-fuelled sports machines of the former Communist bloc. East Germany, which tried for two decades to develop a record-setting 100 metres sprinter by selecting the cream of the athletic crop as toddlers, nurturing them with the best coaching and conditioning, and then pumping them with steroids, still never managed to produce even one sub-10-second 100 metres runner. In fact, no white, Asian or, indeed, African runner not from the west of the continent has ever broken 10 seconds.
It's a different story with middle- and long-distance events. After about 45 seconds of intense, anaerobic activity, when aerobic energy comes into play, athletes of West African origin hit a physiological wall. In contrast, East Africans, who have small and slender ectomorphic body types (and so are generally relatively poor sprinters), dominate distance running.