Human legs can only run so fast: Here's why

So far, the fastest any human has run is about 27 1/2 mph, a speed reached (briefly) by sprinter Usain Bolt just after the midpoint of his world-record 100-meter dash in 2009.

Kenichi Ito: The 'world's fastest man on four legs', The Independent

Elevating Legs: Health Benefits, How To, Precautions

How Fast Can A Human Run, Really?

Yes, Men Run Faster Than Women, but Over Shorter Distances and Not by Much - Neuroscience News

Blount's Disease Symptoms, Causes & Treatment

The science of long-distance running revealed, including the roles of energy, carbohydrates (as in pasta), water, salts, lactic acid, and dopamine, as well as aspects of homeostasis

Humans Walk Weird. Scientists May Finally Know Why

Do people with long legs run faster than people with shorter legs? - Quora

Long-distance running and evolution: Why humans can outrun horses but can't jump higher than cats.

The Human Body Is Built for Distance - The New York Times

Why Do My Legs Feel Heavy When Running?