A pair of running shoes provided with a housing at the heel thereof, into one of which an electronic device is removably mounted. The electronic device comprises a normally open inertia switch for producing a footstrike count, an oscillator crystal for providing a stopwatch function, a sound generating...http://www.google.com/patents/US4771394?utm_source=gb-gplus-sharePatent US4771394 - Computer shoe system and shoe for use therewith
