A sensor for detecting the presence of a force exerted by a persons foot on the ground is provided in a shoe, the sensor interposed between the foot and the ground in the region of the sole of the shoe. The sensor includes a resilient compressible elastomeric middle layer of insulating material disposed between a lower conductive fabric layer and a plurality of upper conductive fabric layer portions. The resilient elastomeric layer includes a plurality of embedded electrically conductive metal filaments extending from a first surface towards a second surface of the elastomeric layer. In regions of the sensor compressed by force ‘F’ due to a persons weight the thickness of the elastomeric layer is reduced and so the metal filaments are of sufficient length to provide electrical continuity through the elastomeric layer between the lower and upper conductive fabric. The occurrence of such continuity is monitored and processed by a system to provide data for use in the field of sports training and athlete monitoring applications.