A vertical ground reaction force-measuring treadmill for the analysis of prosthetic limbs

Abstract

This paper presents the development of an instrumented-treadmill, designed for use in the evaluation of prosthetic limbs during amputee running. The motorised treadmill was chosen for this study because of its advantages over conventional ground mounted force platforms, e.g. decreased time required for the data- collection, laboratory space required, repeatability, control of speed, and improved statistical power through collection of a high number of successive foot contacts. The long-term aim of this work is to investigate amputee running and thus identify prosthetic limb/wearer characteristics, which may improve the training process and subsequent running experience. An existing treadmill was modified to measure the ground reaction force underneath the belt. A new treadmill bed was designed using finite element analysis techniques. Four biaxial strain gauge transducers were designed and fabricated in-house to measure the applied loads. The instrumented-treadmill has been statically and dynamically tested and calibrated, showing a maximum error of ± 3% and crosstalk of ± 4% to the horizontal force components, a hysteresis up to 8 N, and a 250 Hz natural frequency. Associated software has been developed to capture, process and display information related to gait data in a format suitable for left and right limb comparison. A pilot study was conducted to examine the force-measuring treadmill for evaluating amputee running.