What Makes Kenyans Superior Runners? It’s Not The Genes

Why are Kenyans superior runners? Genetics has nothing to do with it. Photo: espn.com

Why are Kenyans superior runners? Genetics has nothing to do with it. Photo: espn.com

According to the real experts, Kenyans are no more naturally gifted for running than Canadians are for hockey.

Interview by: Matt Fitzgerald

It is widely assumed that the nation of Kenya dominates the sport of distance running globally because of some kind of genetic advantage. But if you talk to someone who actually knows something about the relationships between genes, race, and running performance, you get a different story. I recently interviewed one such expert, Stephen Roth, PhD, director of the functional genomics laboratory at the University of Maryland, about the idea that Kenyans are born superior runners.

Matt Fitzgerald: Generally speaking, running ability is something we’re either born with or not, correct?

Stephen Roth: Performance itself is really challenging to measure. So most of the studies haven’t actually addressed the genetics of endurance performance so much as they’ve looked at the genetics of VO2max or some other underlying trait. There we see evidence of a genetic contribution. Sometimes as much as half of the variability in a trait [e.g. high VO2max] could be related to genetic factors, while environmental factors [e.g. training] contribute to the other side.

I think a lot of athletes have this idea that there is such a thing as the perfect set of running genes. But does science support that idea?

I don’t think so. That really has become more evident over the last decade or so, since the human genome was sequenced. We’ve found a handful of genes that are contributing to performance-related traits, but they are explaining a very small amount of the variability that we see. So in all likelihood, whatever genetic combination might contribute to Mr. Smith’s marathon performance might be a completely different combination than what’s contributing to Mr. Jones’s marathon performance, even though they’re equally excellent athletes.

If we think of examples of someone like a Frank Shorter, who didn’t have a very high VO2max, but excelled, in part because of a high lactate threshold, then we can think of other runners who have a different set of underlying characteristics who are equally successful.

You can envision different athletes having different advantages. But ultimately performance is about more than just the physiological. It’s who brought their game face, so to speak. And some of this could be genetic as well—certain psychological advantages that they bring even though their physiological advantages may not be extraordinary.

So even if Kenyan runners are genetically different than runners from other places, the “Kenyan way” of being naturally gifted for running is not necessarily the only way.

I think that’s fair to say. If we think of genetic diversity, it’s Africa that’s really the melting pot of the world. There’s more genetic diversity in Africa than there is in the United States or Europe.

If you look within the Kenyan athletes themselves, there’s a ton of genetic diversity there as well. So far the evidence is that, if there is some sort of genetic advantage, it’s very subtle, it’s really hard to identify, and it may not be particularly important beyond the environmental characteristics that these people grow up in, where they’re running miles to school at an early age, it’s ingrained in their culture.

Anecdotally, I’ve heard that the children of some of the elite Kenyan runners really have no special advantage. Once the parents have become elite, they move into middle class or upper class housing and the kids no longer have to run barefoot seven miles both ways to school.

I think a lot of athletes also casually assume that Kenyans may have certain running genes that don’t even exist in other populations. That’s not true, though, is it?

Any genetic advantage found in Kenya or in Africa will be found across the world. The proportion in which that genetic advantage is found could be different. Clearly we have these different races that are distinguishable in part based on their genetic background. So the unique combination of these gene variants that are found in Kenya may very well be a combination that you don’t find elsewhere around the world. But the idea that there’s a unique handful of genetic mutations that are found nowhere else in the world is incorrect.

So if all of the same genes exist everywhere, then runners of the very highest level of natural ability must also exist everywhere. But is it possible that Kenya has more runners at that level?

Because of genetic diversity around the world, you can envision certain populations having more of certain gene variants. Certainly we see that in Tibet and Chile, where these folks can live at altitude and clearly have some genetic predisposition to survive and thrive at altitude that we’re not going to see in a typical European, or frankly even African, setting.

Which do you think is a more likely explanation for Kenyan dominance: they have more naturally gifted runners, or they simply have more runners from which to sift out the most gifted?

Out of 100 people in the United States, how many of them are going to take up distance running? It’s just not valued in our culture. Maybe you get one. Well, is that one going to carry the best combination of running genes out of all the 100 people? Probably not. But in Kenya, maybe 40 out of 100 people take up the sport, because it is such a culturally dominant force. Then your odds just skyrocket.

[sgi:MattFitzgerald]

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