Entropy-based method for COP data analysis

Entropy-based data analysis methods have been applied to many science or engineering fields. The centre of pressure (COP) data are often dynamic, nonlinear and non-stationary in nature. It is thought that it may be used to analyse COP data, which is often used for evaluating postural stability in ergonomics research. Multi-scale entropy (MSE) and empirical mode decomposition are introduced first; then, three examples are presented to demonstrate the initial applications of the proposed methods, young and elderly subjects: (1) standing with attention; (2) standing with eyes open/closed; and (3) wearing vibratory shoes. The MSE analysis results are compared with traditional COP stabilogram metrics. Based on these applications, MSE can be an effective metric for COP data analysis and other ergonomics research. The cautions of using MSE, including the non-specificity nature and individual baseline variation, are also discussed. There is a good potential for using MSE in ergonomics-related research, especially for ageing ergonomics.