This picture doesn’t, but if you look into it then you’ll see studies have shown the Kalenjin people have quite small ankles and calves which mean their legs weigh less and so make it easier for them to run long distances.
That isn’t to say genetics are the sole reason they are good. But it’s undeniable they have a genetic advantage.
Maybe a small advantage, but they also have a culture of training specifically for long distance running. That’s almost all of it. The size of your ankles doesn’t matter if you don’t practice.
There are better ultra marathon runners in Mexico who look nothing like these Kenyans. They barely warm up with a marathon, so they don’t place highly. They are good because their culture involves running ultra marathons. They will keep running for fun long after everyone else has died.
Training is what matters. If you went and joined a running club in Kenya, you would be able to beat any Kenyan who didn’t practice. It’s 99% practice.
I mean yeah no shit someone who trains to run marathons is going to be better at running marathons than someone who doesn’t.
The point is when you get to the highest level, where everyone is putting in the absolute max hard work and training, then their biology gives them an advantage.
My point is, you are putting too much emphasis on genetic gifts. Take a sport like basketball, where being tall is clearly an advantage. It’s a much bigger advantage than “small calves” are in running. You basically can’t play in the NBA at all unless you’re 6ft or taller.
Even among people 6ft 9 and up, you really have to practice with a good teacher. Someone who’s a foot shorter will easily beat you if they are good.
Running isn’t just “moving your legs”. There’s strategy that these guys learn from their running group at a young age. They practice running as a sport. That’s why they’re good.
It’s the same reason why people from the US, who are all genetically different, play basketball and baseball better than most other countries. They practice it competitively when they’re young.