Navegando por Palavras-chave "fadiga muscular"

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    Análise da fadiga muscular localizada em atletas e sedentários através de parâmetros de freqüência do sinal eletromiográfico
    (Sociedade Brasileira de Medicina do Exercício e do Esporte, 2008-12-01) Santos, Marcelo Cláudio Amaral [UNIFESP]; Semeghuini, Tatiana Adamov; Azevedo, Fábio Mícolis de; Colugnati, Diego Basile [UNIFESP]; Negrão Filho, Rúben de Faria; Alves, Neri; Arida, Ricardo Mario [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade do Oeste Paulista Faculdade de Fisioterapia; Universidade Estadual Paulista (UNESP); Instituto de Ensino e Pesquisa Movimentare® Fisioterapia e Reabilitação
    Although the analysis in the frequency domain of the Electromyographic Signal (EMG) has been used in the characterization of the localized muscular fatigue process, its application, specifically the Median Frequency (MF), is rarely explored in sports. The objective of this study was to verify the viability of the EMG signal application, through its frequency domain analysis, as a parameter for determination and differentiation of the behavior of localized muscle fatigue. Two groups of subjects, one characterized as athletes (n = 12) and the other as sedentary (n = 12), were submitted to analysis based on procedures from three different experimental situations, all involving isometric exercise modality: i) maximum test for determination of the Maximum Voluntary Isometric Contraction (MVIC); ii) fatigue test, 35 sec. sustained load of 80% of MVIC; iii) recovery test, 10 sec. sustained load of 80% of MVIC. In the latter, the MF behavior in the three first (Fmedi) and three last (Fmedf) seconds of the EMG signal of tibialis anterior muscle during the fatigue test have been monitored. During the 10 seconds of the recovery test, MF was calculated regarding the whole period (Fmedr); this parameter was used to calculate the Muscular Recovery Index (MRI). The results showed that Fmedf presented lower value in relation to Fmedi in both groups (p < 0.05). Additionally, the Fmedi and Fmedf values for the athlete group were higher in comparison to the sedentary group (p < 0.05). The MRI mean value and standard deviation for the athlete group were 62.1% ± 28.7 and for the sedentary group was 55.2% ± 27.8 (p > 0.05). Therefore, the results presented in this study allow inferring the viability in the application of the frequency domain parameters of the EMG signal for the determination and differentiation of localized muscle fatigue behavior.
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    Efeito agudo dos extensores do joelho unilateral na cadeira extensora com e sem estímulos na plataforma vibratória
    (Sociedade Brasileira de Medicina do Exercício e do Esporte, 2013-10-01) Ferreira, Fernando Roberto [UNIFESP]; Angeli, Gerseli [UNIFESP]; Confessor, Yara Queiroga [UNIFESP]; Gagliardi, João Fernando Laurito; Barros Neto, Turibio Leite de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Unifieo Fundação Instituto de Ensino para Osasco
    INTRODUCTION: A great number of studies have been conducted lately concerning the use of mechanical vibration as part of the training for improvement of physical conditioning. However, the majority of these studies have evaluated the effects of the exercises joined with the vibrating training in order to determine if there was post-training improvement, and did not evaluate the effects of both vibrating and non-vibrating platform exercises. OBJECTIVE: To evaluate the acute effect of exercise on the knee extensors, with and without the stimulus of the vibrating platform. METHODS: Thirty male active individuals, with age range between 18 and 45 years, randomly conducted three protocols: with the platform on (POG), the platform off (POFFG) and control group (CG). Each protocol began with a five minute warm-up on the ergonomic bicycle, with loads ranging from 75 to 100 watts and 70 rotations per minute, followed by six sets of 10 unilateral squats with one minute of pause between them, with or without mechanical vibrating, and finished with the Work Test, performed only on the dominant leg for determination of the physical valences: work, strength, power and speed. RESULTS: Only the variable speed has presented statistically significant difference (p < 0.05) when the platform on was compared to the control. CONCLUSION: The training on the vibration platform had no influence on the work or muscle power variables, but it exerted negative influence on the movement velocity causing fatigue in the quadriceps muscles.