June 27, 2000 -- Plant yourself at the finish line of any long-distance race in the world, and, chances are, the first face you'll see run across the finish line will be Kenyan -- or at least African.
The fact that Africans dominate long-distance running is widely known, but why they dominate is not so clear. In a study published in the June issue of Medicine & Science in Sports & Exercise, Adele Weston, PhD, and colleagues offer some suggestions as to what may account for the many excellent African runners.
The researchers compared eight African runners and eight Caucasian runners. They were evenly matched according to their body size, although the Caucasians were slightly taller. All 16 runners reported their primary race distance to be 10 kilometers, and they all were competitive at the distance.
The runners were put through various treadmill tests, one at race pace. According to the researchers, "this study indicates greater running economy and higher fractional utilization of VO2 peak in African distance runners. Although not elucidating the origin of these differences, the findings may partially explain the success of African runners at the elite level." The technical language really has a simple explanation.
Basically, the Africans used less oxygen to accomplish the same results as the Caucasians. Their running economy -- or how well they used the oxygen consumed -- was 8% better than the Caucasians when adjusted for weight. The Africans still were able, according to Weston, to run at a higher level of intensity with a higher heart rate.
A key aspect of the Africans' success has to do with lactate buildup. Too much lactate in the blood is the bane of any athlete, leading to fatigue and the feeling that "we'd have the bear climb up our back," David E. Martin, PhD, tells WebMD.
Martin, the chairman of sports science for USA Track & Field and a professor of physiology at Georgia State University in Atlanta, explains that the "fractional utilization" Weston wrote about was related to an athlete's peak oxygen consumption in relation to the point of lactate accumulation in the blood.
The fact that the African athletes could compete at a better running economy than the Caucasians at a higher intensity, with about the same amount of lactate accumulation, "suggests the lactate removal may be enhanced in African runners," write Weston and colleagues.
According to Martin, this study is likely an outgrowth of a past study showing that the lactate threshold seemed to be higher among African runners than Scandinavian runners.
"What this study is saying is, it may be that distance runners in Africa may be better than distance runners in other countries because they can race at a faster pace. And, obviously, the person who races at the fastest pace is the person who wins," Martin says.
So, "how come all these hundreds of Kenyans are racing at a faster pace than everyone else?" Martin asks. Is it the loaded issue of genetics, or the more likely answer: training?
In that same study of Scandinavian runners, a muscle biopsy was done of all the athletes, and no genetic difference was found, leading the researcher to propose a training-related phenomenon, says Martin. "The Kenyans tend to train at a higher, or faster pace," he explains.
Most runners tend to train below race pace, says Martin, whereas the Africans run at the higher pace at all times. "If you train at that pace, you'll adapt to that pace," he says, and use less oxygen while resisting lactic acid.
The Kenyans are known for training among hills and high altitude. Although both these things are present in other areas of the world, too, Martin points out that Kenya does have "long hills." He says, "It's a combination of many factors."
Also, Martin says, many Kenyan kids grow up running to school in bare feet, which also tends to build long-term injury protection because of lower limb flexibility. It's a process that can build the ultimate runner.
"These athletes are running machines by the time they start thinking about serious running," Martin says. By that point, they're more resistant to lactic acid accumulation, more resistant to fatigue. "It's like having a fourth gear instead of third gear," he says. "They've got overdrive."
"Whether they lift weights, run hills, or whether they run from childhood, I would think those would be the three likely contributors to running economy," Martin tells WebMD. "It's not all that complicated. These athletes are a product of their environment, just as our American athletes are a product of their environment."