Abstract

An article of performance enhancing footwear having a piezoelectric spring apparatus in the sole member. Walking or running applies a first force deforming a piezoelectric actuator, thereby generating electrical energy. An energy storage circuit stores electrical energy generated by the piezoelectric actuator. Sensing means is provided to sense the release of a second force greater than the first force, which triggers the release of stored electrical energy back into the piezoelectric actuator. The resulting deformation of the piezoelectric actuator imparts a force into the bottom contact surface of the sole member.