Abstract: A footwear system for monitoring weight, posture allocation, physical activity classification, and energy expenditure calculation includes an accelerometer configured to obtain acceleration data indicative of movement of a user's foot or leg. The footwear system may also include a pressure sensing device mounted in an insole and configured to obtain pressure data indicative of pressure applied by a user's foot to the insole, as well as a transmitter communicatively coupled to both the accelerometer and the pressure sensing device and configured to transmit the acceleration and pressure data to a first processing device configured process the acceleration data and the pressure data to distinguish a first posture from a second posture different from the first posture and process the acceleration data and the pressure data to distinguish a first movement-based activity from a second movement-based activity different from the first movement-based activity.