Abstract: An athletic shoe (20) includes a sole (22), an upper (25), and a tongue (26), as well as fasteners (28), such as shoelaces. Incorporated into the sole (22) of the athletic shoe (20) is a receptacle (30) for receiving and retaining a plug-in module (32) in a slide-in, releasably locking arrangement. The plug-in module (32) preferably includes a battery (62), a light emitting device (54), and electrical circuit elements (58, 60, 72) arranged to selectively connect the battery (62) to the light emitting device (54).

Abstract: An inertially responsive lighting system (10) for footwear has at least one electric light source (12), a battery (16), circuit means (22) to connect the battery to the light, and electro-mechanical switching means (24) disposed in the circuit means that are responsive to an inertial impulse force acting on the footwear to cause the light to flash on and off for a brief interval after the force is applied.

Abstract: A replaceable shoe heel spring assembly allows the wearer of a shoe to selectively change the energy absorption and return characteristics of the heel portion of the shoe by changing shoe heel spring cartridges. The wearer activates a release mechanism located on an exterior surface of the shoe and a cartridge containing a shoe heel spring is ejected from a location in the mid-sole of the shoe. Another shoe heel spring cartridge having different energy absorption and return characteristics can then be inserted into the mid-sole. The cartridge is securely held in the mid-sole by a locking mechanism connected to the release mechanism. The shoe heel spring is provided with a cover which matches the material of the mid-sole. The cover assists in preventing debris from entering the mid-sole. The selectable range of energy absorption and return characteristics is limited only by the number of cartridges available.

Abstract: An athletic shoe (20) having an inflatable air bladder (52) integrated into the design and construction of the shoe, and apparatus (50) for inflating the air bladder, as well as apparatus (82) for sensing and indicating the pressure in the bladder, all incorporated into the design of the shoe.