Comparison of Two Contact Detection Methods for Ground Reaction Forces and Moment Estimation During Sidestep Cuts, Runs and Walks

The use of force platforms limits the study of human movement in the laboratory. Promising methods for estimating ground reaction forces and moments minimise a cost function, constrained by the subject's dynamic equilibrium, to distribute the overall force over the contact surfaces. The detection of the contact surfaces is dependent on parameter settings. The aim of this study was to evaluate two contact surface detection methods: one based on foot kinematics and the other based on pressure insoles data. Optimal parameters were identified for both methods on sidestep cuts, runs and walks. Contact can be detected on the basis of a position threshold or of a velocity threshold. Using pressure insoles data to detect contact gives a better estimate of the position of the centre of pressure. The two contact detection methods demonstrated comparable accuracy in terms of estimating the external forces.