Implementation of Electrical Bioimpedance to Determine the Muscular Fatigue of the Vastus Lateralis: Relevance in the Design of Feedback-Controlled Orthosis

Resumen

The detection of muscle fatigue has been indispensable in optimizing electrical bioimpedance myography, a non-invasive and easy-to-use diagnostic method that allows to obtain accurate results on the physiological behavior of the body. The aim of the present work was to perform muscle fatigue detection during physical activity using electrical bioimpedance (EB), examining the feasibility and accuracy of the measurement along with muscle physiological understanding, to implement the EB system in customized orthoses to determine and prevent musculoskeletal injuries more effectively. The vastus lateralis muscle of the volunteer was monitored at the beginning of the physical activity, as well as when he/she presented muscle fatigue when performing constant extension and flexion.  With these data, a frequency analysis was performed with the help of the fast Fourier transform to the signals before the physical activity and when the muscle was fatigued. At the same time, the behavior of the energy distribution in the frequency to identify the harmonics that quantitatively represent the change in the spectral composition of the signal in the behavior of muscle fatigue. In conclusion, significant changes in the spectral composition were identified, these findings suggest that muscle fatigue alters the electrical activity of the muscle, which is reflected by detectable changes in the frequency spectrum.