How do kick starts work?

Answer 1

Most are foot recoil starters. Meaning that a spring is wound by the kicking action of the operator, then is released at the end of the kicking action. The potential energy of the uncoiling spring turns the engine over.

Very few are a foot crank starter. Meaning that the kicking action is directly engaged in the engine's movement. You would feel the individual compression cycle with your foot, if this were the case. (If you slip off the kick start lever during the compression cycle it can snap back and hurt you.)