A sensor system for measuring power generated by a person during running includes a pair of sensor insoles and a portable electronic device. Each of the sensor insoles includes a substrate layer, force sensors, and a transmitter for transmitting data from the force sensors. The portable electronic device performs the steps of: determining a reference distance ratio for the person that is an approximate distance travelled for each step taken by that person； receiving force data from the plurality of force sensors； receiving force data from the pair of sensor insoles； calculating power using the force data and the reference distance ratio； and reporting the power calculated.
