Shoes, devices for shoes, and methods of using shoes

A shoe, comprising:

• a first plate and a second plate that are separate units and that are entirely located in a forefoot portion of the shoe between an upper and an outsole of the shoe, the first plate having a first hinge portion, and the second plate having a hinge portion;
• one or more springs for biasing the first plate and the second plate apart from each other;
• a pin that passes through the first hinge portion of the first plate and the hinge portion of the second plate to hold together the first plate and the second plate;
• wherein the first plate is at least partially rotatable about the pin;
• wherein the hinge portion of the second plate is located between the first hinge portion of the first plate and the second hinge portion of the first plate;
• and
• wherein the hinge portion of the second plate is in contact with the first hinge portion of the first plate and the second hinge portion of the first plate.