In our world, at one point, people only knew how to stand, walk, and sit.
Bartholomew was peacefully walking through a forest. But, suddenly, a llama approached.
The llama then spits on Bartholomew and "walks" away very fast.
Bartholomew was enraged. He was walking so fast that he discovers that picking his legs up to a 45 degree angle makes go faster.
Bartholomew catches the llama, engages in a tickle fight, and wins. Then, the defeated llama walks away.
Bartholomew is amazed at his new talent. He calls it Running. He runs from town to town to spread the word of his new ability. Every human now knows how to run because of Bartholomew's great adventure.