genetics in sport
What research tells us about African runners: are they really genetically more gifted?
Page 1 2...and Bengt Saltin
The most revealing study on this topic was carried out by the renowned Swedish exercise physiologist, Bengt Saltin, who compared sedentary adolescent Kenyans, Kenyan high school runners and elite Kenyan runners with top-level Scandinavian runners. Saltin unearthed a number of important facts. First, relatively sedentary adolescent Kenyans had exactly the same aerobic capacities as sedentary Danish teenagers. If the Kenyans were really genetically superior, you would expect them to have higher VO2maxs than their Scandinavian counterparts (unless their 'superhuman' genes only revealed themselves in response to training).
Second, young Kenyan runners trained with astonishing intensity: About 50 to 60 percent of their total mileage was done at heart rates of 90 percent of maximum or higher! This was significantly higher than the Scandinavians' total and is much higher than anything European and American runners do generally.
Third, and following directly from point two, Kenyan runners - including the high schoolers - were more economical than the elite Scandinavians and also produced less lactate during high-speed running. This makes sense: one of the best ways to boost economy is to train fast, and the Kenyans have the corner on intense training. Also, fast training boosts the aerobic qualities of fast-twitch, type IIa muscle cells and lowers their lactate output, which probably explains why the Kenyans have lower lactate levels during strenuous running. Since high lactates are associated with fatigue, that's a very good thing!
The fourth finding - a critical one for our discussion of whether the Kenyans have a genetic edge - was that sedentary adolescent Kenyans had VO2max readings of 47 (the same as Scandinavians), very active (but non-training) Kenyan teenagers had VO2maxs of about 62, and seriously training high school Kenyan runners checked in with average VO2maxs of 65 to 68. Senior elite Kenyan runners have had their VO2max levels measured at 75 to 85. This progression in aerobic capacities from the mid-40s to high-70s and low-80s is exactly the same as the one observed in Americans (sedentary American youth have VO2max values in the 40s, while topflight runners like Salazar, Ryun, and Prefontaine were in the high 70s and low- to mid-80s). The progression in VO2max values is the same in Kenyans as it is in Americans! In addition, as high school Kenyans become elite senior runners, they increase their number of blood vessels per muscle cell and also enhance the concentrations of energy-producing aerobic enzymes inside their muscle cells. Those are natural responses to hard training and aren't necessarily caused by superior genes.
Calling all Kalenjins
Proponents of the genetic theory often point out that of the more than 35 tribal groups in Kenya, a single tribe - the Kalenjins - has produced most of the great runners (Lelei, Loroupe, Kiptanui, Keino, Kiprotich, Cheromei, Sang, Rono, etc.). The Kalenjins were traditionally a pastoral people who roamed the beautiful Rift Valley of Kenya with their cattle, so one might argue that genes which enhanced the ability to move long distances were 'selected' over evolutionary time. In contrast, members of another large Kenyan tribe, the Luo, have traditionally fished for a living and have produced few top runners..
However, political and social forces inside the country tend to favour the development of Kalenjins at the expense of other tribes. In spite of this, the recent trend in Kenyan running has been for non-Kalenjins (Ndeti, Kamau, Kinuthia, Masya, Osano, Asiago, Osoro, Karori, etc.) to become more prominent as time goes by, rather than for Kalenjins to increase their dominance. Most notably, the Kikuyu tribe, always a fine source of running talent (five-time world champion John Ngugi is Kikuyu), is beginning to produce more and more excellent runners, even though the Kikuyus have not interbred with Kalenjins and historically were not a nomadic people. In fact, running talent may be fairly equally distributed among Kenya's tribes. In other words, the Kalenjin-genetic hypothesis weakens once you take a closer look at what's really going on. How could so many different groups of non-interbreeding people produce top runners, if genetic factors were really the paramount factor?
So what's the real reason?
If genes aren't responsible, what accounts for the difference between African and non-African running? The African approach to training differs from the American-European method in a number of ways, including intensity (Africans usually train more intensely but with less mileage), the amount of hill training (there's no comparison here; the Africans are almost always working on hills), periodisation (Africans vary their training more - favouring big upswings and then gentle troughs; in fact, many Africans take a month or two away from running while their American and European peers continue to plug away without a break), and diet (Africans eat more carbohydrate, less protein, and less fat). Africans also benefit from a decade-long 'base' period - just running back and forth to junior school at moderate speeds - before they take up serious running, while Americans and Europeans tend to simply plunge into competition in more senior school without a prolonged, strength-boosting build-up..
Many of these factors have already been studied in scientific settings. We know that intensity is the most potent producer of fitness, yet American and European runners still preach the merits of high mileage. We know that hill training is better than flat-ground running, yet American and European runners often limit hill work to once a week. We know that the African diet is more conducive to elite performances, yet American and European runners continue to edge toward more protein and fat..
In addition, our book on periodisation - how to structure training over rather prolonged periods of time in order to produce the best-possible performances - is still empty, or - rather - it's filled with lots of theory and little hard data, so it's perhaps in this area that the Africans can be our pragmatic teachers. It's clear that the African pattern of very hard work followed by very thorough rest fits better with human physiology than the American and European scheme of hard work - and then more hard work. The human body always reaches optimal functioning more readily when stress is combined with recovery, rather than when stress is continuously kept at a taxing level..
The bottom line?
Rather than speculating about superior genes, let's ask world champions like Mr. Tergat and Ms. Tulu what they are doing in January, March, July and September, and throughout the whole year. Chances are good that we'll pick up some useful information from them. Let's face it, there's no evidence that Africans have a lock on the genes needed for world-record running performances. After all, we don't even know what those genes are, and (as the following note explains) most research has suggested that training and lifestyle - not genetic factors - account for more of the variation in athletic performances. So let's give the Africans credit for earning their world-beating performances. And let's learn from them about how to perform at the best-possible level..
Could geneticists ever demonstrate convincingly that Kenyans are genetically superior? Of course! They would simply have to identify the genes which are important for endurance performance and show that those genes are more prevalent in Kenyan runners..
This can't be done at present. We simply don't know which genes are critical for enhancing performance, so we can't measure their frequencies in Kenyans, Americans, Slovenians, Siberians, or anyone else. Identification of such genes will probably happen, but not for another five to 10 years at least..
In the meantime, we might try to look at genetic differences indirectly - by examining physiological differences between Kenyans and non-Kenyans and then making inferences about genetics. For example, we might compare Kenyan and American five-year-olds, before either group has had a chance to do any training (even a smattering of training might make one group look better than the other). If we found no physiological differences, it would appear that the Kenyans did not enjoy an inherent genetic advantage..
However, even if the Kenyans were fitter, it would be hard to argue convincingly that the difference was genetic. After all, the Kenyan kids would probably eat differently than the Americans (fruits and vegetables versus Snickers bars), their everyday activity patterns would be different (Kenyans would gather wood and haul water while Americans would watch the box), and many of the Kenyan youngsters would probably be residing at altitude. All of these factors - diet, habitual activity and altitude residence - can have a strong impact on physiology, so the Kenyan kids' edge might have nothing to do with genetics..
How about training previously sedentary groups of Kenyans and Americans of various ages and then observing their responses to training? Of course, we would try to make everything as similar as possible: Americans and Kenyans would have the same training history and be the same weight, height, age, etc. If the Kenyans improved by 30 percent in response to our training programme while the Americans went up by only 15 percent, wouldn't that show that Kenyans had special genes which boosted their responsiveness to training?
Well, no. Again, the Kenyan difference might simply be due to prior lifestyle factors such as diet, altitude, daily activity, etc. The bottom line is that you can't look at Kenyan world-beating performances and say 'Aha! It's genetic!' Too many other factors can account for performance differences. As the great geneticist Claude Bouchard, Ph.D., says: 'There's currently no evidence that the Kenyans are genetically superior.'
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