A method of forming an article of apparel having a sensor system includes extruding one or more polymeric materials onto the article of apparel to form one or a plurality of sensors. The polymeric material(s) may have a conductive particulate material dispersed therein. Conductive leads connecting the sensors to a port may also be formed of a polymeric material having a conductive particulate material dispersed therein. The conductive material may be dispersed in the sensor(s) at a first dispersion density and in the leads at a second dispersion density. Each of the sensors is configured to increase in resistance when deformed under pressure, which is detected by a module connected to the port. The second dispersion density is such that each of the leads has sufficient conductivity that the leads are configured to conduct an electronic signal between each sensor and the port in any state of deformation.