Less is more: high pass filtering, to remove up to 99% of the surface EMG signal power, improves EMG-based biceps brachii muscle force estimates

Potvin, Jim R.; Brown, Stephen H.M.

doi:10.1016/j.jelekin.2003.10.005

Cited by 198 publications

(163 citation statements)

References 41 publications

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“…Although studies 29,37,38 try to find solutions featuring new methodological developments for this limitation, it is not yet possible to make a direct relationship between electromyographic findings and muscle strength.…”

Section: Resultsmentioning

confidence: 99%

Mastigação habitual e atividade eletromiográfica dos músculos masseter e temporal em escolares de 7 a 12 anos

et al. 2014

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Conflict of interest: non-existent stimulation of supporting structures, such as bones and teeth and for favoring that the harmonious craniofacial growth occurs³ .The chewing pattern can be influenced by several factors, such as occlusal interferences, dental and/ or periodontal problems, tooth loss, muscle and/or temporomandibular joints problems².It is known that in a unilateral mastication, the chewing muscles are mainly characterized by increased muscle strength on the working side, in other words, where chewing is occurring. The muscles of the balancing side, opposite side to the working side, is generally more elongated and with NTRODUCTIONChewing is considered by many authors as one of the most important and most studied functions of the stomatognathic system¹,². When performed in a alternating bilateral way, there is synchrony of masticatory muscles, which in turn are crucial for the ABSTRACT Purpose: to investigate the relationship of the masticatory preference side in the electrical activity of masseter and temporalis muscles. Methods: the sample was composed by 115 children aged between 7 and 12 years. The acquisition of the electrical activity of the masticatory muscles was recorded during 5 seconds of isometric contraction in maximal intercuspal position. The children were divided into four groups according to masticatory preference observed: Chewing Preferential Right, Left, Bilateral Alternating, and Bilateral Simultaneous. The electromyographicdata were analyzed using the SPSS 17.0 software, and for determination of statistical difference between the electrical activity of the right and left masseter and temporalis muscles was performed by Paired Student t-test (p <0.05). Results: from the total of 115 children, 76 (63.4%) had a preferred side during mastication, whereas 44 (36.7%) children had masticatory right and 32 (26.7%) preferred chewing left. Of the individuals without a preferred side, it was found 25.8% (n = 31) alternating with bilateral chewing and 10.8% (n = 13) with simultaneous bilateral chewing. After comparing the electrical activity of the masseter and temporal, right and left, according to the group chewing, it was found that the average electrical activity of the muscles on the left side showed no statistically significant differences when compared with the average of its peers right side. Conclusion: for the study sample, there was no relationship between the habitual chewing side and electrical activity of the muscles masseter and temporal.

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Section: Resultsmentioning

confidence: 99%

Mastigação habitual e atividade eletromiográfica dos músculos masseter e temporal em escolares de 7 a 12 anos

et al. 2014

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“…Increasing magnitude of the processed signal is representative of increasing sEMG activity (Cram & Kasman, 1998). Rectification and low-pass filtering results in processed data with a shape representing force production and time lag approximating the electromechanical delay of muscles to a stimulus (Potvin & Brown, 2004).…”

Section: Discussionmentioning

confidence: 99%

Spectral Analysis of Root-Mean-Square Processed Surface Electromyography Data as a Measure of Repetitive Muscular Exertion

Gant¹,

Fethke²,

Gerr³

2012

PsycEXTRA Dataset

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Highly repetitive motion is associated with upper extremity musculoskeletal disorders (UEMSDs) among industrial workers, especially when encountered concurrently with forceful exertions. Current methods of estimating occupational exposure to "repetitiveness" provide information about the repetitiveness of joint motion, but fail to provide complete information about the repetitiveness of muscular exertion, a more biomechanically meaningful measure of repetition. This thesis introduces an innovative digital signal processing method, from which muscular exertion frequency was estimated. Specifically, time series recordings of muscle activity obtained with surface electromyography (sEMG) were processed with standard root-mean-square (RMS) amplitude calculations and then transformed from the time domain into the frequency domain. The mean power frequencies of the RMS-processed sEMG signals (MPF EMG ) were then calculated to estimate muscular exertion frequency.In a laboratory-based validation study involving repetitive isometric hand gripping exertions, MPF EMG was compared to established measures of muscular exertion frequency and joint motion frequency across a range of known exertion frequencies, exertion intensities (i.e. forces), and exertion durations (i.e., duty cycles). Strong linear relationships were observed between MPF EMG and external measures of muscular exertion frequency. However, performance of MPF EMG as a measure of muscular exertion frequency may be improved with an increase of the signal to noise ratio in the sEMG data. Signal processing parameters were therefore investigated and alternative techniques were explored. Alternative processing parameters were suggested to minimize difference between MPF EMG and established methods of muscular exertion frequency.A second laboratory-based validation study compared MPF EMG to an established measure of muscular exertion frequency and a widely-used measure of joint movement frequency during a simulated industrial task. Although a stronger linear relationship was observed between metrics of joint motion frequency and established measures of 2 muscular exertion, the differences between measures were not meaningful and the relationship between MPF EMG and established measures was moderate-to-strong.The final phase of this thesis explores the application of the newly proposed techniques to field-based data collected during a study of ironworkers involved in construction stud-welding tasks. Limitations in data collection limited the analysis of MPF EMG in this study.The research presented in this thesis introduces a novel metric based on the frequency analysis of RMS processed sEMG data, and presents evidence that MPF EMG has potential to be a valuable assessment technique of exposure to repetitive muscular exertion.Abstract Approved: _____________________________________ Thesis Supervisor

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“…The modulation of the EMG yields to a lower correlation between muscle activity and force output during sustained contractions. Thus, previous studies have tried to improve the linear correlation by removing low frequency components of EMG signals [Potvin and Brown, 2004;Staudenmann et al, 2006], reducing common components in the EMG [Farina et al, 2004;Potvin and Brown, 2004;Staudenmann et al, 2006]. …”

Section: Relationship Between Force Variability and Emg Activitymentioning

confidence: 99%

Spatial reorganisation of muscle activity correlates with change in tangential force variability during isometric contractions

Mista

Salomoni

Graven‐Nielsen

2014

Journal of Electromyography and Kinesiology

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The aim of this study was to quantify the effects of spatial reorganisation of muscle activity on task-related and tangential components of force variability during sustained contractions. Three-dimensional forces were measured from isometric elbow flexion during submaximal contractions (50 s, 5-50% of maximal voluntary contraction (MVC)) and total excursion of the centre of pressure was extracted. Spatial electromyographic (EMG) activity was recorded from the biceps brachii muscle. The centroids of the root mean square (RMS) EMG and normalised mutual information (NMI) maps were computed to assess spatial muscle activity and spatial relationship between EMG and task-related force variability, respectively. Result showed that difference between the position of the centroids at the beginning and at the end of the contraction of the RMS EMG and the NMI maps were different in the medial-lateral direction (P < 0.05), reflecting that muscle regions modulate their activity without necessarily modulating the contribution to the taskrelated force variability over time. Moreover, this difference between shifts of the centroids was positively correlated with the total excursion of the centre of pressure at the higher levels of contractions (>30% MVC, R2 > 0.30, P < 0.05), suggesting that changes in spatial muscle activity could impact on the modulation of tangential forces. Therefore, withinmuscle adaptations do not necessarily increase force variability, and this interaction can be quantified by analysing the RMS EMG and the NMI map centroids.3

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Less is more: high pass filtering, to remove up to 99% of the surface EMG signal power, improves EMG-based biceps brachii muscle force estimates

Cited by 198 publications

References 41 publications

Mastigação habitual e atividade eletromiográfica dos músculos masseter e temporal em escolares de 7 a 12 anos

Mastigação habitual e atividade eletromiográfica dos músculos masseter e temporal em escolares de 7 a 12 anos

Spectral Analysis of Root-Mean-Square Processed Surface Electromyography Data as a Measure of Repetitive Muscular Exertion

Spatial reorganisation of muscle activity correlates with change in tangential force variability during isometric contractions

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