Abstract: An apparatus and method of operation for measuring forces applied to a wearer's foot, the apparatus providing an indication to the wearer when forces on the foot exceed pre-selected upper limits or do not meet pre-selected lower limits. A body member is disclosed for attachment around the wearer's foot, the body member having an exterior sole and an interior sole portion covered by a rigid foot plate. The foot plate includes an upper support surface for contact with the foot. The interior sole portion includes at least one cavity within, with a force sensing unit attachable partially within the cavity. At least one strain gage is positioned at a midpoint on the force sensing unit, and the force sensing unit is connectable to the underside of the foot plate. An electronic means is mounted within the cavity and is electrically connected to the at least one strain gage.