If you were the parent of a 14 year old American boy with a BMI of 15.5, the neighbors would whisper about neglect and possibly report you to child & family services. In Kenya, on the other hand, their home could be considered an Olympic training camp for long-distance runners.
That’s one of the surprising results of an exciting new (free, full-text) study of the daily energy expenditure of Rift Valley adolescents: Boys are very, very skinny. which could be one of the reasons why they are also so fast in drag races.
Reading: Run as fast as kenyans
For decades, many observers of Kenya’s success story have guessed that Rift Valley runners dominate distance running because they spend their childhood “training” by running or walking to school and working in the fields. American kids ride the school bus, watch TV after school, and struggle to keep up with major marathons.
Recently, an experienced team of Kenyan experts, including Yiannis Pitsiladis from the University of Glasgow and Daniel Lieberman from Harvard, decided to test the early training theory. They thought that young Kenyans who ran and walked the most in their daily lives would have the highest VO2 max scores, a measure of potential running success. however, their tests of 30 young men and women did not support the hypothesis. In other words, the Kenyans who ran and walked the most did not have the highest VO2 max scores. this tends to undermine the early training theory.
But that does not imply that Kenyan children are sedentary. hardly. they averaged 7.5 kilometers a day, jogging to and from school. still, this doesn’t exactly equate to marathon training, not when they were making four trips a day (to school, home for lunch, back to school, back home) averaging about 1.1 miles in every way.
what really stands out is the low body mass index of Kenyans (see table below). When you are fit and have a low body mass index, you also have a high VO2 max, as the two are inversely related. young rift valley subjects were tested for VO2 max through a tough interval running routine on a 400-meter makeshift (and undulating) track. According to Jack Daniels’ “Oxygen Energy” tables, untrained young Kenyans who attended a school that is not known for producing track and field champions may have the potential to run a 2:18 (men’s) marathon or 2:39 (women). and those are the “average” scores; The paper did not report the full range of observed vo2 max scores, so we do not know how the fittest boys and girls performed.
Mean body mass index, vo2 max. and rift valley 14 year old marathon potential
[new information: the article’s lead author, alexander gibson, has just responded to my request for the full range of data by reporting that three of the boys exceeded 80 ml*kg/min, with the top runner reaching 81 ,6. based on the potency of oxygen, 80 confers potential for a marathon of 2:07:38 and 81.9 a 2:05:06. the top girl reached 68.9 ml*kg/min, giving a potential of 2:25:08. says gibson: “it was clear from the start that we were studying a remarkable population by seeing them complete the running tests, sometimes at speeds of up to 18 km/hour at altitude and using a handheld accelerometer. it was also evident when looking at the children in their rural, homey setting, running to and from school, occasionally carrying books, younger siblings, or water.”]
but do skinny kids with high vo2 max scores become championship runners? Daniels says it’s quite possible, based on a longitudinal test he conducted many years ago with teenage runners. he found that they gained weight as they matured, but also gained muscle, with the result that they were able to keep their maximums high.
lieberman, who is now in kenya working on his next project, says he was not at all surprised by the results. “We’ve known that children are physically active from a young age, live at high altitudes and don’t eat junk food,” he says.
pitsiladis believes the study paints a bleak picture for the future distance efforts of runners in the Western world. “It’s no wonder that Steve Cram, David Moorcroft and Sebastian Coe still hold strong UK times with little or no chance of breaking their records,” he says. “Our young population is simply too inadequate overall, so there is little chance of extremely talented athletes emerging. similarly, these data explain why East Africans (i.e., Kenyans in particular) will continue to dominate middle- and long-distance running, further perpetuating the unproven notion that Kenyan long-distance runners have a Superior genetics for long-distance racing.”
Here’s another new report on 14 fully mature but skinny Kenyan marathoners with an average best time of 2:07:16. if I did my math correctly, they have a ratio of height (in inches) to weight (in pounds) of .53. You can compare yourself by dividing your height by your weight. higher is better. if you’re somewhere around .5, you might have a chance against the Kenyans. if you’re in the .4xs or .3xs, you should challenge them to a bowling match.
On the day I won the Boston Marathon in 1968, my ratio was 0.52. but now I’ve sunk into the .4xs.