The Myth of Genetic Superiority
It is obvious that many Kenyans have an excellent body type for running. Scott Douglas wrote in a Slate.com article about a training trip to Kenya: “Under the heavy clothing, I can make out ideal frames for distance running—short torsos, high waists, narrow hips, inverted-teardrop thighs, nearly nonexistent calves. As I plod around in a T-shirt and shorts, I feel less like the 132-pound runner that I am than a fleshy, squat 40-year-old with cankles getting in a few miles before work.”
Such observations are backed up by science. While it is often considered taboo to discuss population-based differences in anatomy, measurements have been taken and it’s simply a demonstrated fact that Kenyans are generally more ectomorphic than most populations.
However, as we have seen, the ideal running body is not the ideal swimming, cycling or triathlon body, so the idea that Kenyans have special innate potential to excel in triathlon simply because they have natural running ability is naïve and false. But the naïveté of this notion may go even deeper than the mistaken assumption that a good body for running is a good body for triathlon.
The reasons for Kenyan dominance in distance running have been hotly discussed for decades. A sizable fraction of those who have an opinion on the matter believe that Kenyans have a genetic advantage over Caucasians and other “races” (scare quotes are used because Kenyan is not a race) with respect to running. But this too is false. Leading experts on the genetics of athletic performance say there is no support for the idea that Kenyans are better runners from birth.
Among these experts is Stephen Roth, Ph.D., director of the functional genomics laboratory at the University of Maryland. According to Roth, the idea that Kenyans have genetic advantages as runners is based on very shallow assumptions about the relationships between genes, race and athletic performance.
Perhaps the most egregious assumption is that there is one set of perfect genes for running performance, of which the average Kenyan has more. In fact, says Roth, the evidence suggests that the genetic underpinnings of running performance are so complex that it’s possible to have enough natural talent to be a great runner with all kinds of different gene combinations.
“We’ve found a handful of genes that contribute to performance-related traits, but they explain a very small amount of the variability that we see,” Roth said.
This means that having some of the known “running genes” is no guarantee of great running ability, while not having them is no guarantee of poor running ability, and it also suggests that there are many, many more as-yet-unknown genes that influence running performance.
“So in all likelihood,” Roth said, “whatever genetic combination might contribute to Mr. Smith’s marathon performance might be a completely different combination than what’s contributing to Mr. Jones’ marathon performance, even though they’re equally excellent athletes.”
It is true that in some populations, including that of Kenya’s Kalenjin tribe in the Rift Valley that produces most of the country’s top runners, particular favorable running traits may be common. But that signifies little, as no single genetic trait is indispensable to high-level running. For example, a few studies comparing Caucasian and Kenyan runners have noted that Kenyan runners tend to be more economical. They also tend to have smaller calf circumferences, an anthropometric difference that could partly account for their better running economy. Some have interpreted this dubious connecting of the dots as proof that Caucasian runners are at a hopeless genetic disadvantage in relation to Kenyans, but that’s a bunch of baloney. It is no more necessary to have “Kenyan calves” to be a great runner than it is necessary to be a certain height.
According to Roth, there are literally trillions of different possible bodies that have the potential to reach the highest level of running, and they’re not all Kenyan.
Another bad assumption hidden in the idea that Kenyan running dominance is genetically based is that Kenyans have certain genes favorable to running that are completely absent in other populations. Not so.
“Any genetic advantage found in Kenya or in Africa will be found across the world,” Roth said. “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.”
Because all of the genes that are favorable to running performance exist in every population, odds are that, at any given time, the most genetically gifted runner in the United States (or any other large population) is just as naturally talented as the most genetically gifted Kenyan. Our best are as good as their best. Now, as Roth suggests, it is possible, although unproven, that certain genes or combinations of genes favorable to running performance may be more common in Kenya than elsewhere. But this does not mean their best runners have an advantage over ours. It just means they may have more runners of the highest talent level than we do.