Relationship Between the Electrical Response of a Skeletal Muscle Versus the Applied Force and the Angle of Flexion

Abstract

Studying the relationship between muscle force and some electrical parameters of muscle measured on the surface could serve as an indirect indicator of force that would be useful for various applications In this work, is proposed to find a possible relationship between muscle force and parameters obtained from surface electromyography (and electrical impedance myography (depending on the angle of flexion of the biceps brachii of a case of study A machine was developed that allows fixing an angle of elbow flexion, combined with a dynamometer which allowed the recording of force simultaneously with the EMG and EIM The maximum peak and AC power of the EMG were calculated, as well as the magnitude of the impedance for a range of angles between 0 º (full extension) and 100 º of flexion The magnitude of impedance vs frequency showed 3 decreasing transitions, two small at 400 Hz and 12 KHz and one large at 4 59 MHz An almost linear relationship was obtained between the force and the angle of bending, and a convex nonlinear relationship with a local maximum (at 40 º 80 Nt) between the peak values and the AC power of the EMG vs the angle and force Polynomial models were used to fit the data by minimum squares, being better in the 3 rd and 4 th order An increase in the sample is recommended as well as testing more suitable models for the analytical behavior of the data obtained. Key words : Muscle force , Electrical impedance myography , Muscle modelling