04 September 2008 ~ 0 Comments

TOI Article – 'Why Blacks outrace Whites'

This was supposed to be posted in the “Olympic season” but better late than never.

Why Blacks Outrace Whites

I think any study that starts with the central assumption that there is some great tangible genetic difference between a “black” or “white” person is bound to leave out other possible socio-cultural, geographical or evolutionary biology explanations. I have friends and family who tend to believe that “blacks are faster and stronger” due to the high concentration of successful black track and field athletes (and all ‘Asians’ are smart and good at math and so on) and the mainstream media does not help to question such beliefs and binary modes of thinking. This is dangerous since it serves to cement a ‘difference’ between ‘racial’ groups that does not exist.

Race is socially-constructed, hence there has to be an alternate explanation for why a certain ‘racial’ group seemingly performs better. All things being equal, there is more genetic variation between two people of different heights than between someone with dark skin as opposed to someone with fair skin. Inputs and other studies welcome — I think this merits further research on my part post-exams. Enjoy the read (full article here):

In the last three decades, athletics, like all sports, has become more and more globalised. Athletes from many small countries are participating in international competitions, and technologies are more freely accessible, although at steep costs. In this levelling of the playing field, the rise of black power has stunned the world once used to seeing only whites on the podium. What is behind this polarization? Is it in the genes or is it the desire to win?

It has come under huge scrutiny by scientists and sociologists in the past decade. Over 200 scientific studies have been carried out and many more are going on. The association of skin colour with a genetic structure suited for athletics has not been established. This is more so because among the black athletes, there are two very distinct categories — those from East Africa, who dominate long distance running, and those of West African ancestry who dominate sprints.Most athletes from the Caribbean and North America belong to the latter category as their ancestors were taken to the New World as slaves between the 15th and 19th centuries. The average West African weighs 30kg more than average East Africans, who are small with thin legs and arms.

Studies of East African long distance runners, mainly from Kenya and Ethiopia, have shown that they have the capacity to carry oxygen in their body tissues for longer periods.

According to a study by Yanna Pitsiladis, director of the International Centre for East African Running Science (ICEARS), this appears to be a result of living at a higher altitude and constantly running since childhood.

All elite Kenyan and Ethiopian runners have grown up in locations that are up to 2,500 meters above sea level. Among the Kalenjin people in the Western Highlands of Kenya, people run practically all their lives, starting from going to school.

Pitsiladis carried out mitochondrial DNA and Y-chromosome analysis of over 400 DNA samples from Kenya, including elite runners, looking for some genetic differences. ‘‘There is no evidence to date of a genetic phenomenon,’’ he told TOI.

Training systems also help in developing certain abilities like the stunning burst of speed of East African long distance runners at the fag end of a gruelling run. Timothy Noakes of the University of Cape Town told TOI that these athletes train in such a way that they are able to keep some muscle units unused till the end.

So, while other runners are suffering from exhaustion of the relevant muscles, the East Africans bring into play a fresh set of muscle fibres. They also appear to maintain speed at high concentrations of lactate — which builds up in the muscles and leads to fatigue — unlike whites or West Africans.

Studies indicate that sprinters of West African descent have a higher proportion of fast-twitch muscles that are useful in short explosive bursts, but tire out very quickly after that.

Whites, on average, have larger and more muscular upper-bodies, with relatively shorter arms and legs. This gives them an advantage in sports needing strength rather than speed — weightlifting, wrestling and throw events like the shot put and hammer. This physiology is also suited for swimming, another sport dominated by whites.

Some of the intriguing theories still under test include the role of enzymes like angiotensin converting enzyme (ACE). Eritrean runners have been found to contain a version of the ACE-producing gene that causes better oxygen consumption suitable for endurance running.

Similarly, a study by Kathryn North of Australia showed that a protein called ACTN-3, which helps in producing short bursts of energy, was more prevalent in sprinters from West Africa. But nothing conclusive has emerged. As Yann C Klimentidis, a human evolutionary scientist at the University of New Mexico, told TOI, ‘‘It has been difficult to determine what, if any, genetic factors may account for the success of runners of African ancestry. These are questions and some genes have been proposed, but it’s been inconclusive.’’ Most researchers agree that external factors and not genes are the key to performance.

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