Why do we have the arch in our feet?

The arch has two main functions:

Support body weight while we are standing
Work with other bones, ligaments, and tendons to produce a spring-like propulsion while we are walking or running

Some research also hints at a role in gripping and climbing trees.

The arch absorbs the shock and compresses when our feet hit the ground. The tendons and ligaments in the arch can store elastic energy. This energy is used in the second stage as the arch recoils and pushes us forward.

The compression and recoil save a lot of effort, much like the bounce of a rubber ball. It can save and return up to 17% of the mechanical effort. Running would have been a lot more tiring if we didn't have this spring-like mechanism in our feet.

Arch height, width, and shape differ from one person to another. Babies are born with flat feet. The arch starts to take shape during the childhood, and the shape keeps changing from childhood to adolescence.