This paper details the development of a multi-sensor platform designed to support functional monitoring and knee rehabilitation via its integration into a smart garment. The system incorporates flexible conductive polymer sensors, interfaced to a customized body sensor node with embedded accelerometer and gyroscope sensors. The body node was specifically developed for unobtrusive sensor data acquisition and the wireless transmission of data via a Bluetooth link. To demonstrate the system, a proof of concept investigation was conducted to assess its potential for functional monitoring in the context of daily activity discrimination. Preliminary results show that walking, running, stairs climbing and descending activities can be easily discriminated based on the data collected with the developed sensing platform. Moreover, simple clustering and discrimination of the tested activities is shown to be feasible based on a single time domain signal power feature.