The Distribution of Force under the Human Foot—An On-Line Measuring System

Abstract

The distribution of force under foot is an important parameter for assessing different surgical procedures on it. In order to develop a clinical tool to do this completely and accurately, a system has been developed based on resistance strain gauge load cells. These have an exposed area 15 × 15 mm square and have been assembled in square modules of 16. Eight such modules (128 load cells in all) have been brought together in a 4 × 2 arrangement to form a load sensitive area 250 × 125 mm. To condition and process the data the load cells have been connected through amplifiers, a multiplexer and an analogue to digital converter to a PDP 11/40 minicomputer. This has been programmed to give as one option a hard copy graphic representation of the actual outline of the foot with the force readings printed in a superposed matrix. Force/time curves can also be plotted for individual cells.