Eli5: how are humans, who are two legged, able to out endure creatures that are four legged?

Question

Eli5: how are humans, who are two legged, able to out endure creatures that are four legged?

In: 1455

Answer 1

All great explanations here, but one thing that hasn’t been mentioned much is our leg shape. The Achilles tendon alone makes humans ridiculously efficient, because it allows us to regain a lot of the energy we use when stepping. It acts as a spring, storing energy on the downward stride, and releasing it when we push off.

Then there is the human butt. We have a huge ass which powers our long legs.