Patent ID: 8617033

Claim:
An exercise footwear apparatus, comprising: a self-expanding sole assembly movable between an expanded configuration and a compressed configuration, the sole assembly comprising: a lower sole portion; an upper sole portion movable with respect to the lower sole portion; and an expansion mechanism configured to allow the self-expanding sole assembly to begin to collapse an appreciable amount after a user steps onto the self-expanding sole assembly and after a substantial portion of the user's weight is supported by the sole assembly, and the expansion mechanism is configured to expand the sole assembly after removal of the substantial portion of the user's weight, wherein the expansion mechanism does not provide an appreciable propelling force as the user steps off a support surface, and wherein the expansion mechanism is configured to provide a resistive force that controls collapse of the sole assembly; and wherein a magnitude of the propelling force, if any, is less than about 50% of a maximum magnitude of the resistive force.