Why is the back and front of a shoe harder than the middle?

There is an extra piece in the toe (called a toe puff) and another in the back of the shoe (called a conter) which will make those parts extra sturdy. These pieces are dipped in a solvent and dry and stiffen once they’re in the shoe.

In order to support the heel there is a small wooden stick between the heel and the sole. It used to be a sturdier metal piece but shoes kept setting off airport security devices so now they use wood instead.