The Potential for Error With Use of Inverse Dynamic Calculations in Gait Analysis of Individuals With Lower Limb Loss: A Review of Model Selection and Assumptions

Abstract

In Brief Lower limb joint kinetics are among the most commonly reported values after instrumented gait analysis and are typically estimated via inverse dynamic calculations. These calculations require, among other things, the selection of a link-segment model that is representative of the subject being tested. In applying inverse dynamics calculations to a standard link-segment model, several assumptions are commonly made in an effort to simplify the calculations. These assumptions regarding the link-segment model are derived from conventional anatomy and physiology and therefore may not be valid when applied to individuals with lower limb loss because their unique anatomical characteristics and the design of lower limb prosthetic componentry may not be accurately accounted for. This article reviews the validity of applying these common assumptions to the analysis of individuals with lower limb loss, with the goal of enabling prosthetists to better judge the quality and accuracy of empirical research findings by furthering their understanding of inverse dynamic theory and its application to the quantitative gait analysis of individuals with lower limb loss. Lower limb joint kinetics are among the most commonly reported values after instrumented gait analysis and are typically estimated via inverse dynamic calculations. In applying inverse dynamics calculations to a standard link-segment model, several assumptions are commonly made in an effort to simplify the calculations. This article reviews the validity of applying these common assumptions to the analysis of individuals with lower limb loss, with the goal of enabling prosthetists to better judge the quality and accuracy of empirical research findings by furthering their understanding of inverse dynamic theory and its application to the quantitative gait analysis of individuals with lower limb loss.