Understanding the effect of window length and overlap for assessing sEMG in dynamic fatiguing contractions: A non-linear dimensionality reduction and clustering

JOURNAL OF BIOMECHANICS

卷:125

Article

De la Fuente, Carlos^1,2,3,4  Martinez-Valdes, Eduardo⁵  Ignacio Priego-Quesada, Jose⁶  Weinstein, Alejandro⁴  Valencia, Oscar^4,7  Kunzler, Marcos R.¹  Alvarez-Ruf, Joel^8,9  Carpes, Felipe P.¹ 

[1] Univ Fed Pampa, Lab Neuromech, Uruguaiana, Brazil

[2] Pontificia Univ Catolica, Fac Med, Dept Cs Salud, Carrera Kinesiol, Santiago, Chile

[3] Clin MEDS, Santiago, Chile

[4] Univ Valparaiso, Ctr Invest & Desarrollo Ingn Salud, Valparaiso, Chile

[5] Univ Birmingham, Sch Sport Exercise & Rehabil Sci, Ctr Precis Rehabil Spinal Pain CPR Spine, Coll Life & Environm Sci, Birmingham, W Midlands, England

[6] Univ Valencia, Dept Phys Educ & Sport, Res Grp Sport Biomech, Valencia, Spain

[7] Univ Los Andes, Lab LIBFE, Escuela Kinesiol, Santiago, Chile

[8] Univ Metropolitana Ciencias Educ, Dept Kinesiol, Lab Cognic & Comportamiento Sensoriomotor, Santiago, Chile

[9] Univ Desarrollo, Fac Med Clin Alemana, Lab Biomecan Clin, Carrera Kinesiol, Santiago, Chile

关键词: Electromyography;    Methods;    Muscle activation;    Fourier;    Gastrocnemius medialis;    Fatigue;   

DOI  :  10.1016/j.jbiomech.2021.110598

来源: Elsevier

【 摘 要 】

The Short-Time Fourier transform (STFT) is a helpful tool to identify muscle fatigue with clinical and sports applications. However, the choice of STFT parameters may affect the estimation of myoelectrical manifestations of fatigue. Here, we determine the effect of window length and overlap selections on the frequency slope and the coefficient of variation from EMG spectrum features in fatiguing contractions. We also determine whether STFT parameters affect the relationship between frequency slopes and task failure. Eighty-eight healthy adult men performed one-leg heel-rise until exhaustion. A factorial design with a window length of 50, 100, 250, 500, and 1000 ms with 0, 25, 50, 75, and 90% of overlap was used. The frequency slope was non-linearly fitted as a task failure function, followed by a dimensionality reduction and clustering analysis. The STFT parameters elicited five patterns. A small window length produced a higher slope frequency for the peak frequency (p < 0.001). The contrary was found for the mean and median frequency (p < 0.001). A larger window length elicited a higher slope frequency for the mean and peak frequencies. The largest frequency slope and dispersion was found for a window length of 50 ms without overlap using peak frequency. A combination of 250 ms with 50% of overlap reduced the dispersion both for peak, median, and mean frequency, but decreased the slope frequency. Therefore, the selection of STFT parameters during dynamic contractions should be accompanied by a mechanical measure of the task failure, and its parameters should be adjusted according to the experiment's requirements.

【 授权许可】

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