An inner sole board having varying regions of flexibility is provided for use in an article of footwear. The inner sole board may include different materials along its length at different locations that vary its flexibility. An inner sole board is manufactured in an injection molding process requiring only one mold. The process includes a first step of providing a mold, a second step of providing an injection molding assembly, a third step of preparing an injection molding assembly and mold, a fourth step of injecting material into the mold, and a fifth step of establishing the dimensions of a first portion. During the injection molding process, the flow rate of at least one material may be controlled by a nozzle gate to control the shape and size of the flex zone it creates. In this manner, the inner sole board may be customized for a specific sport or individual.