Dennis Kimetto - what are we Westerners still missing about Kenyan Marathoners?

Two separate, European-led studies in a small region in western Kenya, which produces most of the race-winners, found that young men there could, with only a few months training, reliably outperform some of the West's best professional runners. In other words, they appeared to have a physical advantage that is common to their community, making it probably genetic. The studies found significant differences in body mass index and bone structure between the Western pros and the Kenyan amateurs who had bested them. The studied Kenyans had less mass for their height, longer legs, shorter torsos, and more slender limbs. One of the researchers described the Kenyan physical differences as "bird-like," noting that these traits would make them more efficient runners, especially over long distances.

Racial politics can make the genetics of African athleticism difficult to talk about in the West.

Surprisingly, Western popular writing about Kenyans' running success seems to focus less on these genetic distinctions and more on cultural differences. For years, the cultural argument has been that Kenyans become great runners because they often run several miles to and from school every day. But, about a decade ago, someone started asking actual Kenyans if this was true, and it turned out to be a merely a product of Western imaginations: 14 of 20 surveyed Kenyan race-winners said they'd walked or ridden the bus to school, like normal children do. Another cultural argument says they run barefoot, which develops good habits, but if this were true then surely the far more populated countries of South Asia, where living without shoes is also common, would dominate over Kenyans. Another ascribes it to the "simple food" of Kenya, but this again is true of many parts of the world, and Kenya's not-so-great health record suggests the country has not discovered the secret to great nutrition.

Source:

http://www.theatlantic.com/international/archive/2012/04/why-kenyans-make-such-great-runners-a-story-of-genes-and-cultures/256015/

Leading the charge in penetrating the Kenyan mystique has been Bengt Saltin, a Swedish physiologist who heads the Copenhagen Muscle Research Centre in Denmark. In the 1990s, Saltin's group began comparing Kenyan and Scandinavian runners by scrutinizing their physiological makeups and assessing the "trainability" of novice runners in both countries.

A decade later, the scientists have ruled out most of the popular explanations for Kenyans' domination of running. Altitude is not the key to the riddle, they have found, because there's no difference between Kenyans and Scandinavians in their capacity to consume oxygen. And the Kenyan diet is on the low side for essential amino acids and some vitamins as well as fat, says Dirk Christensen of the Copenhagen center: "In spite of the diet, they perform at high level." The running-to-school hypothesis was demolished as well: Kenyan children aren't any more physically active than their Danish peers. Do Kenyans try harder? The researchers found that the Danes actually pushed themselves harder on a treadmill test, reaching higher maximum heart rates.

An important clue is the ability of Kenyans to resist fatigue longer. Lactate, generated by tired, oxygen- deprived muscles, accumulates more slowly in their blood. Comparisons of lactate levels have suggested to Saltin's group that Kenyan runners squeeze about 10% more mileage from the same oxygen intake than Europeans can.

Just as more aerodynamic cars get better gas mileage, the Kenyan build helps explain their fuel efficiency. A recent British TV documentary described the Kalenjin as possessing "birdlike legs, very long levers that are very, very thin [on which they] bounce and skip" along.

Saltin's group has quantified this observation. Compared with Danes, the thinner calves of Kenyans have, on average, 400 grams less flesh in each lower leg. The farther a weight is from the center of gravity, the more energy it takes to move it. Fifty grams added to the ankle will increase oxygen consumption by 1%, Saltin's team calculates. For the Kenyans, that translates into an 8% energy savings to run a kilometer. "We have solved the main problem," declares Henrik Larsen of the Copenhagen center. "Kenyans are more efficient because it takes less energy to swing their limbs."

However, slim lower legs are not the whole story. Kenyan runners also have a higher concentration of an enzyme in skeletal muscle that spurs high lactate turnover and low lactate production. Saltin says that this results in an "extraordinarily high" capacity for fatty acid oxidation, which helps wring more energy out of the muscles' biochemical reactions. Because intense training alters the body's biochemistry, Saltin says that he can't say for sure whether the ezyme levels are due to genes or training. But he adds, "I think it's genetic." Research in South Africa jibes with the Copenhagen group's findings.

A team led by exercise physiologist Adele Weston of the University of Sydney, Australia, compared black South Africans, whose running strengths are similar to those of Kenyans, with white runners. The two groups had similar VO2 max values—that is, when putting out maximum effort, they used up the same amount of oxygen per kilogram of body weight per minute. But the black runners were more efficient in their oxygen consumption, lasting on a treadmill at maximum speed for twice as long as the whites. As with the Kenyans, the black South African runners accumulated less lactate and had higher levels of key muscle enzymes.

Source:

http://www.jonentine.com/reviews/AAAS_peeringUnderTheHood.htm

These Kenyan runners tend to have slim legs, with high calf muscles (a genetic trait), which is a very efficient anatomy for a runner.

Source:

http://www.theguardian.com/science/2004/aug/05/1

fisky wrote:

Here's what scientists have to say on East African distance running success. Short story: It's primarily genetics.

Two separate, European-led studies in a small region in western Kenya, which produces most of the race-winners, found that young men there could, with only a few months training, reliably outperform some of the West's best professional runners. In other words, they appeared to have a physical advantage that is common to their community, making it probably genetic. The studies found significant differences in body mass index and bone structure between the Western pros and the Kenyan amateurs who had bested them. The studied Kenyans had less mass for their height, longer legs, shorter torsos, and more slender limbs. One of the researchers described the Kenyan physical differences as "bird-like," noting that these traits would make them more efficient runners, especially over long distances.

Racial politics can make the genetics of African athleticism difficult to talk about in the West.

Surprisingly, Western popular writing about Kenyans' running success seems to focus less on these genetic distinctions and more on cultural differences. For years, the cultural argument has been that Kenyans become great runners because they often run several miles to and from school every day. But, about a decade ago, someone started asking actual Kenyans if this was true, and it turned out to be a merely a product of Western imaginations: 14 of 20 surveyed Kenyan race-winners said they'd walked or ridden the bus to school, like normal children do. Another cultural argument says they run barefoot, which develops good habits, but if this were true then surely the far more populated countries of South Asia, where living without shoes is also common, would dominate over Kenyans. Another ascribes it to the "simple food" of Kenya, but this again is true of many parts of the world, and Kenya's not-so-great health record suggests the country has not discovered the secret to great nutrition.

Source:

http://www.theatlantic.com/international/archive/2012/04/why-kenyans-make-such-great-runners-a-story-of-genes-and-cultures/256015/

This aticle is discussing an opinion, but the authors are not identifying any specific genes associated with Kenyan running success.

Leading the charge in penetrating the Kenyan mystique has been Bengt Saltin, a Swedish physiologist who heads the Copenhagen Muscle Research Centre in Denmark. In the 1990s, Saltin's group began comparing Kenyan and Scandinavian runners by scrutinizing their physiological makeups and assessing the "trainability" of novice runners in both countries.

A decade later, the scientists have ruled out most of the popular explanations for Kenyans' domination of running. Altitude is not the key to the riddle, they have found, because there's no difference between Kenyans and Scandinavians in their capacity to consume oxygen. And the Kenyan diet is on the low side for essential amino acids and some vitamins as well as fat, says Dirk Christensen of the Copenhagen center: "In spite of the diet, they perform at high level." The running-to-school hypothesis was demolished as well: Kenyan children aren't any more physically active than their Danish peers. Do Kenyans try harder? The researchers found that the Danes actually pushed themselves harder on a treadmill test, reaching higher maximum heart rates.

An important clue is the ability of Kenyans to resist fatigue longer. Lactate, generated by tired, oxygen- deprived muscles, accumulates more slowly in their blood. Comparisons of lactate levels have suggested to Saltin's group that Kenyan runners squeeze about 10% more mileage from the same oxygen intake than Europeans can.

Just as more aerodynamic cars get better gas mileage, the Kenyan build helps explain their fuel efficiency. A recent British TV documentary described the Kalenjin as possessing "birdlike legs, very long levers that are very, very thin [on which they] bounce and skip" along.

Saltin's group has quantified this observation. Compared with Danes, the thinner calves of Kenyans have, on average, 400 grams less flesh in each lower leg. The farther a weight is from the center of gravity, the more energy it takes to move it. Fifty grams added to the ankle will increase oxygen consumption by 1%, Saltin's team calculates. For the Kenyans, that translates into an 8% energy savings to run a kilometer. "We have solved the main problem," declares Henrik Larsen of the Copenhagen center. "Kenyans are more efficient because it takes less energy to swing their limbs."

However, slim lower legs are not the whole story. Kenyan runners also have a higher concentration of an enzyme in skeletal muscle that spurs high lactate turnover and low lactate production. Saltin says that this results in an "extraordinarily high" capacity for fatty acid oxidation, which helps wring more energy out of the muscles' biochemical reactions. Because intense training alters the body's biochemistry, Saltin says that he can't say for sure whether the ezyme levels are due to genes or training. But he adds, "I think it's genetic." Research in South Africa jibes with the Copenhagen group's findings.

A team led by exercise physiologist Adele Weston of the University of Sydney, Australia, compared black South Africans, whose running strengths are similar to those of Kenyans, with white runners. The two groups had similar VO2 max values—that is, when putting out maximum effort, they used up the same amount of oxygen per kilogram of body weight per minute. But the black runners were more efficient in their oxygen consumption, lasting on a treadmill at maximum speed for twice as long as the whites. As with the Kenyans, the black South African runners accumulated less lactate and had higher levels of key muscle enzymes.

Source:

http://www.jonentine.com/reviews/AAAS_peeringUnderTheHood.htm

This study is identifying primarily physiological differences between European and African runners. It cannot conlude whether these differences are due to genetic differences or training/lifestyle culture differences and their influences over a lifetime.

These Kenyan runners tend to have slim legs, with high calf muscles (a genetic trait), which is a very efficient anatomy for a runner.

Source:

http://www.theguardian.com/science/2004/aug/05/1