Parametric characterization of the spectrum of the electromyographic signal of the biceps during voluntary isometric contraction

The electromyographic (EMG) signal, which is used for exploration of neuromuscular functions, is often quantitatively characterized by the structure of its spectrum. This structure correlates with variations in the metabolic state of a muscle which lead to fatigue. A quantitative measure is proposed for characterizing this structure and thus the EMG spectrum. Experiments were carried out on healthy subjects. Each subject was made to stand with biceps vertical along the body, and carried a weight such that the angle between the arm and forearm was 90°. Ag-AgCl electrodes of 1-cm² surface area were used to detect the signal. The experimental method, the analysis method, and the results are discussed