The effects of innervation zone on electromyographic amplitude and mean power frequency during incremental cycle ergometry

Malek, Moh H.; Coburn, Jared W.; Weir, Joseph P.; Beck, Travis W.; Housh, Terry J.

doi:10.1016/j.jneumeth.2006.01.019

Cited by 62 publications

(106 citation statements)

References 47 publications

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“…The proximity of the EMG electrodes to a muscle's innervation zone can affect features of the EMG signal (de Luca 1997), and the innervation zone can show considerable variability in its location for certain muscles (Rainoldi et al 2004). However, normalized measures of EMG amplitude have been shown to remove the sensitivity to electrode placement for cycling-based studies (Malek et al 2006), and such an approach has been used here to quantify the patterns of activity. We have recently used cross-correlation to shown that the cross-talk in raw EMG signal between adjacent muscles for our cycle tests has r 2 Ͻ 0.04 (Wakeling 2008b), and thus Ն96% of the EMG signal measured from an electrode can be ascribed to that muscle.…”

Section: Discussionmentioning

confidence: 99%

Neuromechanics of Muscle Synergies During Cycling

Wakeling¹,

Horn²

2009

Journal of Neurophysiology

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. Muscle synergies have been proposed as building blocks that could simplify the construction of motor behaviors. However, the muscles within synergistic groups may have different architectures, mechanical linkages to the skeleton, and biochemical properties, and these put competing demands on the most appropriate way to activate them for different mechanical tasks. This study identifies the extent to which synergistic patterns of muscle activity vary when the mechanical demands on a limb were altered, and additionally identifies how consistent the spectral profiles of the electromyographic (EMG) intensities were across the different movement tasks. The muscle activities were measured with surface EMG across 10 muscles in the leg during cycling at a range of loads and velocities. The EMGs were quantified by their intensities in time-frequency space using wavelet analysis; the instantaneous patterns of activity identified using principal component analysis, statistically compared and further visualized using the varimax rotation. Variability (35.7%) in the patterns of activity between the muscles were correlated with the torque and velocity of the pedal crank. Anatomic groups of muscles share a common mechanical action across a joint; uncoupling between such muscles was identified in 68.8% of the varimax patterns that encompassed all 10 muscles and 20.8 -29.5% of the activity patterns when the anatomic groups were analyzed separately. The EMG spectra showed greatest heterogeneity for the gastrocnemii. These results show that the activity of muscles within anatomic groups is partially uncoupled in response to altered mechanical demands on the limb.

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Section: Discussionmentioning

confidence: 99%

Neuromechanics of Muscle Synergies During Cycling

Wakeling¹,

Horn²

2009

Journal of Neurophysiology

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“…Similarly, Malek et al 24 reported that the absolute EMG amplitude was greater for the distal location relative to directly on or proximal to the IZ during incremental cycle ergometry for the vastus lateralis muscle. Their findings, 23,24 in conjunction with more recent results by DeFreitas et al, 22,25 suggest that the IZ may influence the EMG signal during various muscle actions.…”

Section: Muscle Nerve 44: 424-431 2011mentioning

confidence: 87%

“…19 The majority of studies examining the effects of the IZ on neuromuscular response patterns to exercise perturbations have predominantly focused on the EMG signal. [22][23][24] For example, Beck et al 23 reported that electrodes placed directly over the IZ and within 10 mm proximal to the IZ for the vastus lateralis resulted in reductions in the absolute EMG amplitude relative to the more distal sites during isometric muscle actions. Similarly, Malek et al 24 reported that the absolute EMG amplitude was greater for the distal location relative to directly on or proximal to the IZ during incremental cycle ergometry for the vastus lateralis muscle.…”

Section: Muscle Nerve 44: 424-431 2011mentioning

confidence: 99%

“…[22][23][24] For example, Beck et al 23 reported that electrodes placed directly over the IZ and within 10 mm proximal to the IZ for the vastus lateralis resulted in reductions in the absolute EMG amplitude relative to the more distal sites during isometric muscle actions. Similarly, Malek et al 24 reported that the absolute EMG amplitude was greater for the distal location relative to directly on or proximal to the IZ during incremental cycle ergometry for the vastus lateralis muscle. Their findings, 23,24 in conjunction with more recent results by DeFreitas et al, 22,25 suggest that the IZ may influence the EMG signal during various muscle actions.…”

Section: Muscle Nerve 44: 424-431 2011mentioning

confidence: 99%

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Mechanomyographic responses are not influenced by the innervation zone for the vastus medialis

Malek¹,

Coburn²

2011

Muscle and Nerve

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“…O sinal EMG reflete a somação linear algébrica dos sinais elétricos gerados pelas unidades motoras (UM) ativas dentro da área de registro do eletrodo 9 . A amplitude e a frequência do sinal EMG podem refletir a ativação e a velocidade de condução do potencial de ação nas UMs 10,11 , quantificados, respectivamente, pelo valor eficaz (root mean square -RMS) e frequência mediana (FM).…”

Section: Introductionunclassified

Eletromiografia do bíceps braquial em contrações dinâmicas

Cerqueira

Carvalho

Pompeu

2013

Rev Bras Med Esporte

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RESuMoIntrodução: A reprodutibilidade da atividade eletromiográfica de superfície (EMG) é mais estudada em protocolos que envolvem contrações isométricas. Alguns fatores relacionados às contrações dinâmicas podem contribuir para a instabilidade do sinal mioelétrico e dificultar a reprodutibilidade da medida da EMG. Objetivo: Determinar a reprodutibilidade teste-reteste e quantificar o erro téc-nico da medida da frequência mediana (FM) e da amplitude (root mean square, RMS) da EMG, em contrações dinâmicas e estáticas. Métodos: Dez sujeitos foram testados em dois dias, sendo a atividade EMG registrada na maior porção do bíceps braquial. No primeiro dia foi feito o teste de uma repetição máxima (1RM) e de contração voluntária máxima (CVM). No segundo dia foram realizadas duas séries de 10 contrações dos flexores do cotovelo com 75% de 1RM, entremeadas por 1 h em repouso. Antes de cada série foi realizada uma CVM. Resultados: Para a FM e RMS foi observado alto coeficiente de correlação intraclasse para o sinal do bíceps braquial (CCI = 0,90-0,98 para a FM; CCI = 0,89-0,94 para o RMS) e de baixo para moderado coeficiente de variação (CV = 2,5-6,2% para a FM; CV = 14,6-16,3% para o RMS) em ambos os testes. Não foi observada diferença significativa entre teste e reteste (p > 0,05). Conclusão: A FM e o RMS apresentam alta confiabilidade e baixo a moderado erro em contrações estáticas e dinâmicas, possibilitando o uso da EMG para investigação da fadiga e de desordens neuromusculares.Descritores: músculo esquelético, fadiga muscular, análise espectral, eletromiografia. for RMS) and low to moderate coefficient of variation ABStRAct Introduction: Reproducibility of electromyographic activity (EMG) is the most studied in protocols involving isometric contractions. Some factors related to dynamic contractions may contribute to the instability of the myoelectric signal and affect the reproducibility of the measurement of EMG. Objective: To determine the test-retest reproducibility and quantify the technical error of the measurement of the median frequency (MF) and amplitude (root mean square, RMS) of the surface EMG in static and dynamic contractions. Methods: Ten subjects were tested in two days with the EMG activity recorded for the greatest portion of the biceps brachii tendon. In the first day the subjects did one test of maximum repetition (1MR) and maximal voluntary contraction (MVC

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The effects of innervation zone on electromyographic amplitude and mean power frequency during incremental cycle ergometry

Cited by 62 publications

References 47 publications

Neuromechanics of Muscle Synergies During Cycling

Neuromechanics of Muscle Synergies During Cycling

Mechanomyographic responses are not influenced by the innervation zone for the vastus medialis

Eletromiografia do bíceps braquial em contrações dinâmicas

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