Whole body inverse dynamics over a complete gait cycle based only on measured kinematics

Ren, L; Jones, RK; Howard, D

Abstract

This paper presents a three-dimensional (3D) whole body multi-segment model for inverse dynamics analysis over a complete gait cycle, based only on measured kinematic data. The sequence of inverse dynamics calculations differs significantly from the conventional application of inverse dynamics using force plate data. A new validated ‘‘Smooth Transition Assumption’’ was used to solve the indeterminacy
problem in the double support phase. Kinematic data is required for all major body segments and, hence, a whole body gait measurement protocol is presented. Finally, sensitivity analyses were conducted to evaluate the effects of digital filtering and body segment parameters on the accuracy of the prediction results. The model gave reasonably good estimates of sagittal plane ground forces and moment; however, the estimates in the other planes were less good, which we believe is largely due to their small magnitudes in comparison to the sagittal forces and moment. The errors observed are most likely caused by errors in the kinematic data resulting from skin movement artefact and by errors in the estimated body segment parameters. A digital filtering cut-off frequency of 4.5 Hz was found to produce
the best results. It was also shown that errors in the mass properties of body segments can play a crucial role, with changes in properties sometimes having a disproportionate effect on the calculated ground reactions. The implication of these results is that, even when force plate data is available, the estimated joint forces are likely to suffer from similar errors.

Citation

Ren, L., Jones, R., & Howard, D. Whole body inverse dynamics over a complete gait cycle based only on measured kinematics. Journal of Biomechanics, 41(12), 2750-2759. https://doi.org/10.1016/j.jbiomech.2008.06.001

• Journal Article Type: Article
• Deposit Date: May 16, 2011
• Journal: Journal of Biomechanics
• Print ISSN: 0021-9290
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 41
• Issue: 12
• Pages: 2750-2759
• DOI: https://doi.org/10.1016/j.jbiomech.2008.06.001
• Keywords: Three-dimensional, gait model, whole body, inverse dynamics
• Publisher URL: http://dx.doi.org/10.1016/j.jbiomech.2008.06.001