Alternative approach to modal gait analysis through the Karhunen–Loève decomposition: An application in the sagittal plane

This article uses the Karhunen–Loève decomposition (KL) technique, also known as proper orthogonal decomposition (POD) or principal component analysis (PCA), to introduce the concept of gait mode, which can be used as a tool to identify gait differences among subjects or groups and to approximate gait curves. The KL is a statistical pattern analysis technique for finding dominant structures in an ensemble of data. This technique can be used to decompose a spatiotemporal signal into time-independent, orthogonal, spatial components and time-dependent amplitudes. This study demonstrates the existence of a common gait mode through the analysis of the kinematics of 57 young, healthy subjects, and how they can be used to identify different walking patterns, for instance differentiating male and female subjects.