Análise da reprodutibilidade de parâmetros no domínio da frequência do sinal EMG utilizados na caracterização da fadiga muscular localizada

Abstract

A fadiga muscular pode ser definida como qualquer redução na capacidade do sistema neuromuscular em gerar força (ZWARTS et al., 2008). A perda da capacidade do músculo em gerar força pode ter duas origens: uma central e uma periférica. A fadiga de origem central pode ser definida como uma degradação progressiva Motriz, Rio Claro, v.18 n.3, p.456-464, jul./set. 2012 Analysis of reliability of EMG signal frequency domain parameters used in the characterization of localized muscle fatigueAbstract: The aim of this study was to analyze the reproducibility of the electromyography signal´s parameters (EMG) in the frequency domain used in the characterization of localized muscle fatigue. Fifteen male subjects underwent a fatigue test based on isometric knee extension, being held at three different times at intervals of seven days. To assess the reproducibility of data between the tests we calculated the correlation coefficient (ICC) for the median frequency (MF) in total exercise time (MF T ), MF obtained for every 10% of exercise time (MF 10% ) and the powers of the frequency bands obtained by dividing the power spectrum at windows of 20 Hz. The results showed: (1) excellent reproducibility for MF T , (2) good reproducibility for MF 10% , and (3) greater variation in the signal EMG bands from 20 to 120 Hz, especially at the bands of 20-40 Hz and 40-60 Hz, which showed greater sensitivity to the process of muscle fatigue. We conclude that the MF is a variable that shows good reproducibility and that the fragmented analysis of the power spectrum, by means of frequency bands, showed that significant variations occur in the EMG signal during the installation of the fatigue process, having potential to become a new method for the characterization of localized muscle fatigue.

Electromyographic assessment of women's pelvic floor: What is the best place for a superficial sensor?

“…Regarding the MF, it is usually used to evaluate the muscular fatigue and it also may be used to classify the predominant types of muscle fibers . However, since the protocol used does not allow fatigue analysis, the discussion will be focused on types of muscles fibers.…”

Fadiga dos músculos extensores do punho diminui a força de preensão palmar

“…Larivière et al 40 showed the same change on the MF in the gluteus maximus muscle when they analyzed the specificity of an exercise about the "Roman Chair" in healthy people or people with low back pain. Da Silva et al 41 evaluated the reproducibility of MF in muscle fatigue located in the quadriceps venters and concluded that the MF is a reproducible and sensitive parameter for the characterization of muscle fatigue. Accordingly, Rota et al 28 describe the influence of muscle fatigue of the pectoralis major muscle and the muscles of the forearm in decreasing the performance of tennis athletes.…”

Influence of Breathing Modes and Facial Growth Patterns on Electromyographic Fatigue of Masticatory Muscles in Children

“…These changes include mandible posture and occlusal changes and influences on the facial growth pattern. [5][6][7][8][9] Some studies have shown that MBs typically have an elongated face, 5 while others have found mesofacial 10,11 and brachyfacial growth patterns 12 as a characteristic of this population. All these imbalances may potentialize speech, 13 swallowing, 2,9 and mastication changes.…”

“…[17][18][19][20][21] The fatigue depends on the type, duration, and intensity of the exercise; the muscle fiber type; the training level of the individual; and the environmental conditions where the exercise is performed. 5 This variable can be analyzed through electrical activity patterns, mainly obtained with surface electromyography (EMG) by means of isometric contractions, which causes this phenomenon more easily 1,22,23 -although usual isotonic situations are also investigated. 1,22,23 Isotonicity nears the usual training of the masticatory muscles, 24,25 which is why the present study seeks to investigate this situation more in depth.…”