A wireless in-shoe physical activity monitoring apparatus includes left and right shoe sensor systems. A shoe sensor system includes pressure sensing elements, an accelerometer, and a control circuit that includes a power source circuit, a clock circuit, a processing module, memory, a wireless communication transceiver, sensor communication links, and an accelerometer communication link. The processing module samples data from the pressure sensing element to produce foot force data and samples data from the first accelerometer to produce three-dimensional foot data. The wireless communication transmits as outbound radio frequency (RF) signals regarding the foot force data and the three-dimensional foot data.
