To establish whether conducting polymer-coated fabric sensors could be used to monitor breast motion, vertical breast motion of two large breasted women (C+ bra cup) was simultaneously monitored using an OPTOTRAK 3020 motion analysis system (200 Hz) and polymer-coated fabric sensors linked to a custom-made Bluetooth telemetry system (100 Hz) as the subjects walked and ran on a treadmill (7-10 km h(-1)). Sensor strain, change in resistance and vertical breast displacement relative to trunk movement were output for analysis. It was concluded that, although polymer-coated fabric sensors may exhibit a small response lag due to textile geometry changes, they were able to accurately and reliably represent changes in the amplitude of vertical breast displacement during treadmill gait.