Scalable weighted-cumulated methodology for fatigue estimation

作     者：de Oliveira Nascimento, Francisco Assis de Araújo Rocha, Valdinar do Carmo, Jake Carvalho 

作者机构：Group of Digital Signal Processing Department of Electrical Engineering University of Brasília DF BrasíliaCO 04465 Brazil Laboratory of Biological Signal Processing Faculty of Physical Education University of Brasília DF BrasíliaCO 04465 Brazil 

出 版 物：《Research on Biomedical Engineering》 (Res. Biomed. Eng.)

年 卷 期：2022年第38卷第4期

页      面：1087-1101页

核心收录：

基　　金：The present study was supported by the National Council for Scientific and Technological Development (CNPq) and the Federal District Research Support Foundation (FAP-DF)  two Brazilian government agencies for scientific and technological development 

主　　题：Wavelet transforms 

摘      要：Purpose: The objective measurement of muscle fatigue through the analysis of surface electromyographic signals (S-EMG) has been the object of study in recent decades. The use of S-EMG is interesting because it allows accessing the muscular structure and function through the use of a noninvasive technique. This is a subject of interest to many areas of science such as clinical and orthopedic medicine, biomechanics, physiotherapy and rehabilitation, telemedicine, control of interfaces, intelligent prosthetics, and exoskeletons control and for expert systems to support medical diagnosis to neuromuscular diseases. Changes in the spectral signature of the S-EMG signal such as spectral shift for low frequencies and the increase in the dynamic range of the signal indicate the installation of the biological phenomenon of fatigue. For instance, classical techniques such as zero-crossing, median frequency (MDF), and mean power frequency (MPF) are able to perceive the spectral shift in S-EMG signals. On the other hand, techniques such as root mean square (RMS) values can only perceive the variation in the dynamic range of the S-EMG signal. Methods: In this work, new mathematical models for the objective assessment of muscle fatigue are presented. We sought to design models for objective fatigue estimators that simultaneously perceive the spectral shift for low frequencies and the increase in the dynamic range in the S-EMG signal during the instauration of the fatigue process. The new approach is integrated to the weighted-cumulated methodology framework previously proposed. Three new objective muscle fatigue estimators were conceived: the scalable weighted-cumulated Fourier estimator, the weighted-cumulated wavelet estimator (SWCW), and the weighted-cumulated p-side lobe attenuation algorithm (p-SL). Results: To evaluate the proposed tools based on the scalable weighted-cumulated methodology, we investigated two dynamic protocols with muscle fatigue production. The S-EMG signa