Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue

Detalhes bibliográficos
Autor(a) principal: Becman, Eric Cito
Data de Publicação: 2019
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
Texto Completo: http://www.teses.usp.br/teses/disponiveis/41/41135/tde-18112019-102118/
Resumo: Surface electromyography (EMG) is a non-invasive technique to measure on-going changes in the electrical potentials of a muscle of interest. The EMG record is known to display alterations when assessed throughout sustained contractions. For instance, a frequency shift and compression of the signal\'s power spectrum density towards lower-frequencies. It is believed that a reduction of muscle fibre conduction velocity explains at least partially such dynamics. Additionally, the muscle acidosis observed at fatiguing contractions of some exercises seems to alter both conduction velocity and frequency properties. Within this context, the main goal of the present thesis was to explore the effects of muscle buffering capacity manipulation on the EMG power spectrum. More specifically, the mean power frequency (MNF). For manipulating buffering capacity, chronic β -alanine supplementation was used. The randomised and placebo-controlled study measured MNF throughout isometric contractions at submaximal and acidotic intensity (50% of maximal voluntary contraction force) before and after a ?-alanine or placebo supplementation period of 28 days. The β-alanine administration was found to increase muscle endurance, expected result according to the literature. Nonetheless, no visible effect was detected for MNF fatigue behaviour. Under theoretical assumptions, the fatigue behaviour of MNF should change when differences at muscle endurance are found. Thus, the lack of a statistically significant result was discussed in the face of the multifaceted nature of myoelectric signals, composed by influences of several biological and non-biological elements. Secondarily, investigation of EMG signal complexity via a1ApEn is also presented in the body of the thesis, which makes contextual sense, as it had a crucial contribution on the development of methodological aspects of the protocol employed in the main investigation and the overall Master\'s project. Additionally, EMG signal complexity is an underexplored topic and with little information known. Hence, a1ApEn provides potential to assess different EMG information not yet provided by better-documented tools, such as MNF
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spelling Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigueEfeitos do aumento da capacidade tamponante sobre o comportamento do espectro de potências do eletromiograma durante a fadiga muscularBuffering capacityCapacidade tamponanteCarnosinaCarnosineElectromyographyEletromiografiaEspectro de potênciasFadiga muscularMuscle fatiguePower spectrum densitySurface electromyography (EMG) is a non-invasive technique to measure on-going changes in the electrical potentials of a muscle of interest. The EMG record is known to display alterations when assessed throughout sustained contractions. For instance, a frequency shift and compression of the signal\'s power spectrum density towards lower-frequencies. It is believed that a reduction of muscle fibre conduction velocity explains at least partially such dynamics. Additionally, the muscle acidosis observed at fatiguing contractions of some exercises seems to alter both conduction velocity and frequency properties. Within this context, the main goal of the present thesis was to explore the effects of muscle buffering capacity manipulation on the EMG power spectrum. More specifically, the mean power frequency (MNF). For manipulating buffering capacity, chronic β -alanine supplementation was used. The randomised and placebo-controlled study measured MNF throughout isometric contractions at submaximal and acidotic intensity (50% of maximal voluntary contraction force) before and after a ?-alanine or placebo supplementation period of 28 days. The β-alanine administration was found to increase muscle endurance, expected result according to the literature. Nonetheless, no visible effect was detected for MNF fatigue behaviour. Under theoretical assumptions, the fatigue behaviour of MNF should change when differences at muscle endurance are found. Thus, the lack of a statistically significant result was discussed in the face of the multifaceted nature of myoelectric signals, composed by influences of several biological and non-biological elements. Secondarily, investigation of EMG signal complexity via a1ApEn is also presented in the body of the thesis, which makes contextual sense, as it had a crucial contribution on the development of methodological aspects of the protocol employed in the main investigation and the overall Master\'s project. Additionally, EMG signal complexity is an underexplored topic and with little information known. Hence, a1ApEn provides potential to assess different EMG information not yet provided by better-documented tools, such as MNFEletromiografia de superfície (EMG) se trata de uma técnica não invasiva para medir mudanças de potencial elétrico de membrana em um dado músculo. O registro de EMG é conhecido por apresentar alterações ao longo de contrações até a fadiga. Por exemplo, se observa uma compressão das frequências componentes do sinal em direção a bandas de menor frequência. Acredita-se que tal comportamento esteja relacionado a uma redução de velocidade de propagação de impulsos elétricos nas fibras musculares. A acidose muscular vista durante a fadiga em certos exercícios também parece estar correlacionada com ambos aspectos eletrofisiológicos. Nesse contexto, essa dissertação se propõe explorar os efeitos de alterações na capacidade tamponante muscular sobre o espectrograma do registro de EMG. Mais precisamente, sobre a frequência de potência média (MNF) do mesmo. A manipulação da capacidade tamponante se deu pela administração de suplementação nutricional de β-alanina. O estudo, aleatorizado e controlado por grupo placebo, avaliou o comportamento de MNF durante contrações isométricas antes e após um período de suplementação de 28 dias. A intervenção com β-alanina resultou em um aumento da resistência muscular, resultado esperado de acordo com a literatura. Entretanto, nenhuma diferença significativa foi observada em MNF. Teoricamente, o comportamento de MNF durante a fadiga deve carregar mudanças quando o tempo até a falha muscular é aumentado. Assim sendo, foi discutido que a ausência de significância poderia ser consequência do aspecto multifatorial do sinal eletromiográfico, que incorpora influências de numerosos fatores biológicos a não-biológicos. Secundariamente, o estudo da complexidade de sinal do EMG via a1ApEn também foi apresentado, devido a sua relação contextual com o cerne dessa dissertação. Tal estudo foi fundamental para o desenvolvimento de aspectos metodológicos utilizados ao longo do projeto de mestrado. Adicionalmente, o tópico é pouco explorado pela literatura e, por tanto, com potencial de prover informações diferentes daquelas já fornecidas por ferramentas mais famosas, como a MNFBiblioteca Digitais de Teses e Dissertações da USPBerlinck, José Guilherme de Souza Chaui MattosGualano, BrunoBecman, Eric Cito2019-09-12info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://www.teses.usp.br/teses/disponiveis/41/41135/tde-18112019-102118/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2020-01-07T17:18:02Zoai:teses.usp.br:tde-18112019-102118Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212020-01-07T17:18:02Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false
dc.title.none.fl_str_mv Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
Efeitos do aumento da capacidade tamponante sobre o comportamento do espectro de potências do eletromiograma durante a fadiga muscular
title Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
spellingShingle Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
Becman, Eric Cito
Buffering capacity
Capacidade tamponante
Carnosina
Carnosine
Electromyography
Eletromiografia
Espectro de potências
Fadiga muscular
Muscle fatigue
Power spectrum density
title_short Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
title_full Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
title_fullStr Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
title_full_unstemmed Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
title_sort Effects of increased buffering capacity on electromyogram\'s power spectrum density behaviour during muscle fatigue
author Becman, Eric Cito
author_facet Becman, Eric Cito
author_role author
dc.contributor.none.fl_str_mv Berlinck, José Guilherme de Souza Chaui Mattos
Gualano, Bruno
dc.contributor.author.fl_str_mv Becman, Eric Cito
dc.subject.por.fl_str_mv Buffering capacity
Capacidade tamponante
Carnosina
Carnosine
Electromyography
Eletromiografia
Espectro de potências
Fadiga muscular
Muscle fatigue
Power spectrum density
topic Buffering capacity
Capacidade tamponante
Carnosina
Carnosine
Electromyography
Eletromiografia
Espectro de potências
Fadiga muscular
Muscle fatigue
Power spectrum density
description Surface electromyography (EMG) is a non-invasive technique to measure on-going changes in the electrical potentials of a muscle of interest. The EMG record is known to display alterations when assessed throughout sustained contractions. For instance, a frequency shift and compression of the signal\'s power spectrum density towards lower-frequencies. It is believed that a reduction of muscle fibre conduction velocity explains at least partially such dynamics. Additionally, the muscle acidosis observed at fatiguing contractions of some exercises seems to alter both conduction velocity and frequency properties. Within this context, the main goal of the present thesis was to explore the effects of muscle buffering capacity manipulation on the EMG power spectrum. More specifically, the mean power frequency (MNF). For manipulating buffering capacity, chronic β -alanine supplementation was used. The randomised and placebo-controlled study measured MNF throughout isometric contractions at submaximal and acidotic intensity (50% of maximal voluntary contraction force) before and after a ?-alanine or placebo supplementation period of 28 days. The β-alanine administration was found to increase muscle endurance, expected result according to the literature. Nonetheless, no visible effect was detected for MNF fatigue behaviour. Under theoretical assumptions, the fatigue behaviour of MNF should change when differences at muscle endurance are found. Thus, the lack of a statistically significant result was discussed in the face of the multifaceted nature of myoelectric signals, composed by influences of several biological and non-biological elements. Secondarily, investigation of EMG signal complexity via a1ApEn is also presented in the body of the thesis, which makes contextual sense, as it had a crucial contribution on the development of methodological aspects of the protocol employed in the main investigation and the overall Master\'s project. Additionally, EMG signal complexity is an underexplored topic and with little information known. Hence, a1ApEn provides potential to assess different EMG information not yet provided by better-documented tools, such as MNF
publishDate 2019
dc.date.none.fl_str_mv 2019-09-12
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
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dc.identifier.uri.fl_str_mv http://www.teses.usp.br/teses/disponiveis/41/41135/tde-18112019-102118/
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dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv
dc.rights.driver.fl_str_mv Liberar o conteúdo para acesso público.
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Liberar o conteúdo para acesso público.
eu_rights_str_mv openAccess
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dc.publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
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reponame_str Biblioteca Digital de Teses e Dissertações da USP
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