Why Kenyan Runners Dominate—And Why It’s Not Just Genetics

I don’t want you to think I’ve turned this into a running blog—but I do need to correct something from last week’s article.

Besides, this one isn't just about running. It’s a quick dive into one of exercise physiology’s favorite debates: nature vs. nurture in athletic performance.

The correction is to this line:

“Particularly East African runners, whose natural physiology makes them absolute machines over long distances.”

One of my readers asked if that was really accurate.

There’s no doubt that East African countries like Kenya and Ethiopia dominate the long-distance scene. A quick scan of the world marathon rankings shows the men and women runners from these regions filling most of the top 100 spots.

But I was too quick to pin that dominance solely on “natural physiology.”

 

Yes, East African runners often display traits that support endurance performance—high VO₂ max, a greater proportion of slow-twitch muscle fibers, and dense capillary networks.

 

But when you compare those things to elite runners from other parts of the world, they’re not significantly better. Where they do stand out is running economy, which is how efficiently they use oxygen at a given pace.

 

In simple terms, East Africans tend to run faster while burning less fuel.

That said, running economy isn’t just a physiological trait. It’s shaped by biomechanics, body type, and even early life experiences. East African runners tend to be lean, with long legs and slim calves—ideal for endurance efficiency.

 

But there’s no single “running gene” behind it all.

Instead, their dominance looks more like a perfect storm of environmental, cultural, and lifestyle factors.

Most grow up and train between 6,000 and 9,000 feet above sea level.

 

This lifelong exposure to altitude builds adaptations like better oxygen utilization, higher red blood cell counts, and an enhanced running economy—benefits that can take sea-level athletes years to develop, if ever.

Running is woven into everyday life. Many East African athletes log hundreds of miles just getting to school—and often do it barefoot.

One study from 2017 compared children from the region who did not wear shoes to children around the world who always wore shoes growing up.

 

The barefoot group not only had different foot structures and more efficient mechanics, but also had a drastically lower rate of lower-limb injuries—just 8% compared to 61% in the shod group.

 

Although, the article pointed out a major confounding variable.  Kids who grow up without shoes also don't typically have videos games and screens, so they tend to be much more physically active.

Running is more than a sport—it’s a shot at opportunity. In areas where economic hardship is common, athletic success can change a family’s future and that kind of motivation runs deeper than trophies.

 

This rich history of running has also created an ecosystem where competitors in the region are surrounded by other world-class runners, elite coaches, and high-altitude training centers.  They essentially grow up immersed in a system built for producing greatness.

Meanwhile, other East African nations haven’t built the same pipeline. Political instability in Somalia and underinvestment in Tanzania have left them trailing in the development of distance running. 

Even Uganda, despite recent success stories, lacks the depth and infrastructure found in Kenya and Ethiopia.

The traditional Kenyan diet is about 77% carbs, 13% fat, and 10% protein, mostly from fruits, vegetables, unrefined sugars, and a cornmeal mush called ugali. 

 

It’s simple, consistent, and built for endurance.

So, you can start to see how it all stacks up. It's not nature or nurture—but a complex blend of both.

To answer the reader’s question:

 

No, it’s not just “natural physiology.”

It’s environment, culture, training, lifestyle, and yes—a bit of genetic predisposition. But the recipe is far more nuanced than any single ingredient.