Edward C Frederick: Device for determining the speed, distance traversed, elapsed time and calories expended by a person while running. Nike, Banner Birch McKie & Beckett, March 25, 1986: US04578769 (286 worldwide citation)

A device for measuring the speed of a person while running along a surface is disclosed. A pressure switch or transducer located in a shoe senses when a foot of the runner is in contact with the surface and produces a foot contact signal having a duration proportional to the time the foot is in cont ...