51
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de Carvalho M, Swash M. Lower motor neuron dysfunction in ALS. Clin Neurophysiol 2016; 127:2670-81. [DOI: 10.1016/j.clinph.2016.03.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/08/2016] [Accepted: 03/01/2016] [Indexed: 12/11/2022]
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Oliveira JHPD, Dourado Filho MG, Lima NS, Silva HJD, Marcelino Filho M. Relação da espessura e da atividade elétrica do músculo masseter com a força de mordida: um estudo morfológico e eletrofisiológico. REVISTA CEFAC 2016. [DOI: 10.1590/1982-0216201618318915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO: Objetivo: estudar a relação da espessura e da atividade elétrica do músculo masseter com a força de mordida. Métodos: participaram do estudo 17 adultos jovens (21,3 ( 1,4 anos), sendo 7 do gênero feminino e 10 do gênero masculino, saudáveis e clinicamente assintomáticos, quanto a disfunções temporomandibulares. Foi efetuada a medida da espessura do músculo masseter unilateralmente, durante o repouso e contração voluntária máxima. Também foi quantificada a força de mordida para cada lado com um transdutor de força posicionado na região do primeiro molar e simultaneamente avaliou-se atividade elétrica do masseter durante a mordida unilateral. A análise foi baseada na comparação das amostras, sendo utilizados o test t, Wilcoxon, Mann-Whitney e regressão linear multivariada. Resultado: a espessura do músculo masseter foi maior nos homens, tanto no repouso quanto em contração. Observou-se uma simetria entre os lados com os músculos em repouso e em contração. A frequência mediana do sinal eletromiográfico, para o músculo masseter em contração voluntária máxima, não apresentou diferença estatisticamente significante intra-indivíduos e na comparação entre os gêneros. Foi encontrada maior força de mordida nos indivíduos do gênero masculino. Não foi encontrado um modelo de regressão linear multivariada entre as variáveis estudadas. Conclusão: neste estudo, não foi possível encontrar um modelo linear com as variáveis estudadas.
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53
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Park SH, Kwon M, Solis D, Lodha N, Christou EA. Motor control differs for increasing and releasing force. J Neurophysiol 2016; 115:2924-30. [PMID: 26961104 DOI: 10.1152/jn.00715.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 03/09/2016] [Indexed: 11/22/2022] Open
Abstract
Control of the motor output depends on our ability to precisely increase and release force. However, the influence of aging on force increase and release remains unknown. The purpose of this study, therefore, was to determine whether force control differs while increasing and releasing force in young and older adults. Sixteen young adults (22.5 ± 4 yr, 8 females) and 16 older adults (75.7 ± 6.4 yr, 8 females) increased and released force at a constant rate (10% maximum voluntary contraction force/s) during an ankle dorsiflexion isometric task. We recorded the force output and multiple motor unit activity from the tibialis anterior (TA) muscle and quantified the following outcomes: 1) variability of force using the SD of force; 2) mean discharge rate and variability of discharge rate of multiple motor units; and 3) power spectrum of the multiple motor units from 0-4, 4-10, 10-35, and 35-60 Hz. Participants exhibited greater force variability while releasing force, independent of age (P < 0.001). Increased force variability during force release was associated with decreased modulation of multiple motor units from 35 to 60 Hz (R(2) = 0.38). Modulation of multiple motor units from 35 to 60 Hz was further correlated to the change in mean discharge rate of multiple motor units (r = 0.66) and modulation from 0 to 4 Hz (r = -0.64). In conclusion, these findings suggest that force control is altered while releasing due to an altered modulation of the motor units.
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Affiliation(s)
- Seoung Hoon Park
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - MinHyuk Kwon
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Danielle Solis
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Neha Lodha
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida; and Department of Physical Therapy, University of Florida, Gainesville, Florida
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Roman-Liu D. The influence of confounding factors on the relationship between muscle contraction level and MF and MPF values of EMG signal: a review. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2016; 22:77-91. [PMID: 26654476 PMCID: PMC4784495 DOI: 10.1080/10803548.2015.1116817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The purpose of this article is to gather results of studies on the relationship between median frequency (MF) and mean power frequency (MPF) and the level of muscle contraction, and to use those results to discuss the differences in the trends according to factors related to measurement technique and subject. Twenty-one studies with 63 cases for upper limb muscles and nine studies with 31 cases for lower limb muscles were analysed. Most results showed an increase in parameters with an increased level of muscle contraction, only some studies showed a decrease. The influence on parameters of the level of muscle contraction and factors such as subjects, type of contraction, muscle length and electrodes was analysed for each muscle. It was concluded that when analysing the influence of different factors on MF and MPF, because those factors interact they should be considered together, not separately.
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Affiliation(s)
- Danuta Roman-Liu
- Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland
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55
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Hosseinzadeh M, Andersen OK, Arendt-Nielsen L, Samani A, Kamavuako EN, Madeleine P. Adaptation of local muscle blood flow and surface electromyography to repeated bouts of eccentric exercise. J Strength Cond Res 2015; 29:1017-26. [PMID: 25436624 DOI: 10.1519/jsc.0000000000000745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The aim of this randomized controlled crossover study was to investigate the effect of a bout of unaccustomed eccentric exercise (ECC) followed by a consecutive bout of the same intensity on local muscle blood flow, amplitude, and frequency of the electromyographic (EMG) signal from the exercised tibialis anterior muscle. Sixteen healthy male participants (age, 25.7 (0.6) years; body mass index 24.8 (1) kg·m(-2) participated in this study. Two identical bouts of high-intensity ECC were performed on the tibialis anterior muscle 7 days apart. Control sessions involving no exercise were performed 4 weeks either before or after the exercise sessions. Changes in local total blood flow [ΔtHb], EMG root mean square, and median power frequency were recorded during isometric maximum voluntary contraction of ankle dorsiflexion. Measurements were performed before, immediately after, and the day after both ECCs (ECC1 and ECC2). The participants rested quietly in a chair in the control session. Eccentric exercise 1 led to a significant decrease in [ΔtHb] on the day after (p ≤ 0.05), whereas ECC2 did not. Median power frequency decreased significantly in ECC2 compared with ECC1 (p < 0.01). Root mean square was unchanged in all the instants. The present study showed that adaptation is depicted in the local muscle blood flow and the frequency contents of the EMG after an unaccustomed ECC inducing muscle soreness. These alterations provide a potential mechanism for a rapid adaptation, which decreases susceptibility of the muscle to develop further soreness in the subsequent ECC bout.
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Affiliation(s)
- Mahdi Hosseinzadeh
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
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Poosapadi Arjunan S, Kumar DK, Wheeler K, Shimada H, Siddiqi A. Effect of number of motor units and muscle fibre type on surface electromyogram. Med Biol Eng Comput 2015. [PMID: 26223565 DOI: 10.1007/s11517-015-1344-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Reduction in number of motor units (nMU) and fast fibre ratio (FFR) is associated with disease or atrophy when this is rapid. There is a need to study the effect of nMU and FFR to analyse the association with ageing and disease. This study has developed a mathematical model to investigate the relationship between nMU and FFR on surface electromyogram (sEMG) of the biceps muscles. The model has been validated by comparing the simulation outcomes with experiments comparing the sEMG of physically active younger and older cohort. The results show that there is statistically significant difference between the two groups, and the simulation studies closely model the experimental results. This model can be applied to identify the cause of muscle weakness among the elderly due to factors such as muscle dystrophy or preferential loss of type F muscle fibres.
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Affiliation(s)
- Sridhar Poosapadi Arjunan
- School of Electrical and Computer Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia.
| | - Dinesh Kant Kumar
- School of Electrical and Computer Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia
| | - Katherine Wheeler
- School of Electrical and Computer Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia
| | - Hirokazu Shimada
- Department of Computer and Control Engineering, Oita National College of Technology, Oita, Japan
| | - Ariba Siddiqi
- School of Electrical and Computer Engineering, RMIT University, GPO Box 2476, Melbourne, VIC, Australia
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Rodriguez-Falces J, Place N. Power spectral changes of the superimposed M wave during isometric voluntary contractions of increasing strength. Muscle Nerve 2015; 51:580-91. [PMID: 25111456 DOI: 10.1002/mus.24418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 07/25/2014] [Accepted: 08/04/2014] [Indexed: 11/08/2022]
Abstract
INTRODUCTION We examined the power spectral changes of the compound muscle action potential (M wave) evoked during isometric contractions of increasing strength. METHODS Surface electromyography (sEMG) of the vastus lateralis and medialis was recorded from 20 volunteers who performed 4-s step-wise isometric contractions of different intensities. A maximal M wave was elicited by a single stimulus to the femoral nerve and superimposed on the voluntary contractions. The spectral characteristics (Fmean and Fmedian) of sEMG and M-wave signals were calculated. RESULTS M-wave spectral indicators increased systematically with contraction intensity up to 60% MVC and then leveled off at higher forces. Over the 10-60% MVC range, the increase in spectral indicators was 3 times higher for M waves (36%) than for sEMG (12%). CONCLUSIONS The consistent increase in M-wave spectral characteristics with force is due to the fact that the number of motor units recruited by the superimposed supramaximal stimulus is approximately stable.
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Affiliation(s)
- Javier Rodriguez-Falces
- Universidad Pública de Navarra D.I.E.E., Department of Electrical and Electronical Engineering, Campus de Arrosadía s/n., 31006, Pamplona, Spain
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Kawczyński A, Samani A, Mroczek D, Chmura P, Błach W, Migasiewicz J, Klich S, Chmura J, Madeleine P. Functional connectivity between core and shoulder muscles increases during isometric endurance contractions in judo competitors. Eur J Appl Physiol 2015; 115:1351-8. [PMID: 25633071 DOI: 10.1007/s00421-015-3114-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 01/19/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to assess the surface electromyogram (SEMG) changes within and between muscles of the torso and shoulder region during static endurance contraction in elite judokas. We hypothesized an increased functional connectivity of muscles from the shoulder and torso regions during sustained isometric contraction. METHODS Twelve healthy, right-handed judo competitors participated in the study. The SEMG signals from the dominant trapezius (upper, middle and lower part), deltoideus anterior, serratus anterior, and pectoralis major muscles were recorded during isometric endurance contraction consisting of bilateral arm abduction at 90°. The normalized mutual information (NMI) was computed between muscle pairs as an index indicating functional connectivity. RESULTS The NMIs increased significantly during endurance test for 10 of the 15 muscle pairs (P < 0.001). CONCLUSION We concluded that the increases in NMIs highlighted functional changes in the interplay between core and shoulder muscles during an endurance contraction in elite judokas.
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Affiliation(s)
- Adam Kawczyński
- Department of Athletes Motor Skills, University School of Physical Education, al.I.J Paderewskiego 35, Wrocław, Poland
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59
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Ye X, Beck TW, DeFreitas JM, Wages NP. Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold. Hum Mov Sci 2014; 40:24-37. [PMID: 25514631 DOI: 10.1016/j.humov.2014.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 10/23/2014] [Accepted: 11/15/2014] [Indexed: 10/24/2022]
Abstract
The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss.
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Affiliation(s)
- Xin Ye
- Department of Health and Exercise Science, 1401 Asp Ave. Room 104, University of Oklahoma, Norman, OK 73019, USA.
| | - Travis W Beck
- Department of Health and Exercise Science, 1401 Asp Ave. Room 104, University of Oklahoma, Norman, OK 73019, USA
| | - Jason M DeFreitas
- Health and Human Performance, Oklahoma State University, 198 Colvin Rec Center, Stillwater, OK 74078, USA
| | - Nathan P Wages
- Department of Health and Exercise Science, 1401 Asp Ave. Room 104, University of Oklahoma, Norman, OK 73019, USA
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60
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Farina D, Merletti R, Enoka RM. The extraction of neural strategies from the surface EMG: an update. J Appl Physiol (1985) 2014; 117:1215-30. [PMID: 25277737 DOI: 10.1152/japplphysiol.00162.2014] [Citation(s) in RCA: 307] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A surface EMG signal represents the linear transformation of motor neuron discharge times by the compound action potentials of the innervated muscle fibers and is often used as a source of information about neural activation of muscle. However, retrieving the embedded neural code from a surface EMG signal is extremely challenging. Most studies use indirect approaches in which selected features of the signal are interpreted as indicating certain characteristics of the neural code. These indirect associations are constrained by limitations that have been detailed previously (Farina D, Merletti R, Enoka RM. J Appl Physiol 96: 1486-1495, 2004) and are generally difficult to overcome. In an update on these issues, the current review extends the discussion to EMG-based coherence methods for assessing neural connectivity. We focus first on EMG amplitude cancellation, which intrinsically limits the association between EMG amplitude and the intensity of the neural activation and then discuss the limitations of coherence methods (EEG-EMG, EMG-EMG) as a way to assess the strength of the transmission of synaptic inputs into trains of motor unit action potentials. The debated influence of rectification on EMG spectral analysis and coherence measures is also discussed. Alternatively, there have been a number of attempts to identify the neural information directly by decomposing surface EMG signals into the discharge times of motor unit action potentials. The application of this approach is extremely powerful, but validation remains a central issue.
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Affiliation(s)
- Dario Farina
- Department of Neurorehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University, Göttingen, Germany;
| | - Roberto Merletti
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy; and
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado Boulder, Colorado
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Islam MA, Sundaraj K, Ahmad RB, Sundaraj S, Ahamed NU, Ali MA. Longitudinal, lateral and transverse axes of forearm muscles influence the crosstalk in the mechanomyographic signals during isometric wrist postures. PLoS One 2014; 9:e104280. [PMID: 25090008 PMCID: PMC4121292 DOI: 10.1371/journal.pone.0104280] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 07/08/2014] [Indexed: 12/02/2022] Open
Abstract
Problem Statement In mechanomyography (MMG), crosstalk refers to the contamination of the signal from the muscle of interest by the signal from another muscle or muscle group that is in close proximity. Purpose The aim of the present study was two-fold: i) to quantify the level of crosstalk in the mechanomyographic (MMG) signals from the longitudinal (Lo), lateral (La) and transverse (Tr) axes of the extensor digitorum (ED), extensor carpi ulnaris (ECU) and flexor carpi ulnaris (FCU) muscles during isometric wrist flexion (WF) and extension (WE), radial (RD) and ulnar (UD) deviations; and ii) to analyze whether the three-directional MMG signals influence the level of crosstalk between the muscle groups during these wrist postures. Methods Twenty, healthy right-handed men (mean ± SD: age = 26.7±3.83 y; height = 174.47±6.3 cm; mass = 72.79±14.36 kg) participated in this study. During each wrist posture, the MMG signals propagated through the axes of the muscles were detected using three separate tri-axial accelerometers. The x-axis, y-axis, and z-axis of the sensor were placed in the Lo, La, and Tr directions with respect to muscle fibers. The peak cross-correlations were used to quantify the proportion of crosstalk between the different muscle groups. Results The average level of crosstalk in the MMG signals generated by the muscle groups ranged from: 34.28–69.69% for the Lo axis, 27.32–52.55% for the La axis and 11.38–25.55% for the Tr axis for all participants and their wrist postures. The Tr axes between the muscle groups showed significantly smaller crosstalk values for all wrist postures [F (2, 38) = 14–63, p<0.05, η2 = 0.416–0.769]. Significance The results may be applied in the field of human movement research, especially for the examination of muscle mechanics during various types of the wrist postures.
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Affiliation(s)
- Md. Anamul Islam
- AI-Rehab Research Group, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
- * E-mail:
| | - Kenneth Sundaraj
- AI-Rehab Research Group, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
| | - R. Badlishah Ahmad
- AI-Rehab Research Group, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
| | | | - Nizam Uddin Ahamed
- AI-Rehab Research Group, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
| | - Md. Asraf Ali
- AI-Rehab Research Group, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
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Wenzel U, Taubert M, Ragert P, Krug J, Villringer A. Functional and structural correlates of motor speed in the cerebellar anterior lobe. PLoS One 2014; 9:e96871. [PMID: 24800742 PMCID: PMC4011948 DOI: 10.1371/journal.pone.0096871] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/12/2014] [Indexed: 11/19/2022] Open
Abstract
In athletics, motor performance is determined by different abilities such as technique, endurance, strength and speed. Based on animal studies, motor speed is thought to be encoded in the basal ganglia, sensorimotor cortex and the cerebellum. The question arises whether there is a unique structural feature in the human brain, which allows "power athletes" to perform a simple foot movement significantly faster than "endurance athletes". We acquired structural and functional brain imaging data from 32 track-and-field athletes. The study comprised of 16 "power athletes" requiring high speed foot movements (sprinters, jumpers, throwers) and 16 endurance athletes (distance runners) which in contrast do not require as high speed foot movements. Functional magnetic resonance imaging (fMRI) was used to identify speed specific regions of interest in the brain during fast and slow foot movements. Anatomical MRI scans were performed to assess structural grey matter volume differences between athletes groups (voxel based morphometry). We tested maximum movement velocity of plantarflexion (PF-Vmax) and acquired electromyographical activity of the lateral and medial gastrocnemius muscle. Behaviourally, a significant difference between the two groups of athletes was noted in PF-Vmax and fMRI indicates that fast plantarflexions are accompanied by increased activity in the cerebellar anterior lobe. The same region indicates increased grey matter volume for the power athletes compared to the endurance counterparts. Our results suggest that speed-specific neuro-functional and -structural differences exist between power and endurance athletes in the peripheral and central nervous system.
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Affiliation(s)
- Uwe Wenzel
- Institute of Training Science and General Kinesiology, University of Leipzig, Leipzig, Germany
| | - Marco Taubert
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Patrick Ragert
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Jürgen Krug
- Institute of Training Science and General Kinesiology, University of Leipzig, Leipzig, Germany
| | - Arno Villringer
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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63
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Li X, Shin H, Zhou P, Niu X, Liu J, Rymer WZ. Power spectral analysis of surface electromyography (EMG) at matched contraction levels of the first dorsal interosseous muscle in stroke survivors. Clin Neurophysiol 2014; 125:988-94. [PMID: 24268816 DOI: 10.1016/j.clinph.2013.09.044] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 09/26/2013] [Accepted: 09/30/2013] [Indexed: 11/24/2022]
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Rodriguez-Falces J, Navallas J, Malanda A, Rodriguez-Martin O. Comparison of the duration and power spectral changes of monopolar and bipolar M waves caused by alterations in muscle fibre conduction velocity. J Electromyogr Kinesiol 2014; 24:452-64. [PMID: 24774228 DOI: 10.1016/j.jelekin.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/21/2014] [Accepted: 04/01/2014] [Indexed: 02/07/2023] Open
Abstract
The muscle compound action potential (M wave) recorded under monopolar configuration reflects both the propagation of the action potentials along the muscle fibres and their extinction at the tendon. M waves recorded under a bipolar configuration contain less cross talk and noise than monopolar M waves, but they do not contain the entire informative content of the propagating potential. The objective of this study was to compare the effect of changes in muscle fibre conduction velocity (MFCV) on monopolar and bipolar M waves and how this effect depends on the distance between the recording electrodes and tendon. The study was based on a simulation approach and on an experimental investigation of the characteristics of surface M waves evoked in the vastus lateralis during 4-s step-wise isometric contractions in knee extension at 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% MVC. The peak-to-peak duration (Durpp) and median frequency (Fmedian) of the M waves were calculated. For monopolar M waves, changes in Durpp and Fmedian produced by MFCV depended on the distance from the electrode to the tendon, whereas, for bipolar M waves, changes in Durpp and Fmedian were largely independent of the electrode-to-tendon distance. When the distance between the detection point and tendon lay between approximately 15 and 40mm, changes in Durpp of bipolar M waves were more pronounced than those of distal monopolar M waves but less marked than those of proximal monopolar M waves, and the opposite occurred for Fmedian. Since, for bipolar M waves, changes in duration and power spectral features produced by alterations in MFCV are not influenced by the electrode-to-tendon distance, the bipolar electrode configuration is a preferable choice over monopolar arrangements to estimate changes in conduction velocity.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain.
| | - Javier Navallas
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Armando Malanda
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Olivia Rodriguez-Martin
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
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Amaral JF, Alvim FC, Castro EA, Doimo LA, Silva MV, Novo Júnior JM. Influence of aging on isometric muscle strength, fat-free mass and electromyographic signal power of the upper and lower limbs in women. Braz J Phys Ther 2014; 18:183-90. [PMID: 24676705 PMCID: PMC4183246 DOI: 10.1590/s1413-35552012005000145] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 10/15/2013] [Indexed: 12/25/2022] Open
Abstract
Background Aging is a multifactorial process that leads to changes in the quantity and
quality of skeletal muscle and contributes to decreased levels of muscle
strength. Objective This study sought to investigate whether the isometric muscle strength,
fat-free mass (FFM) and power of the electromyographic (EMG) signal of the
upper and lower limbs of women are similarly affected by aging. Method The sample consisted of 63 women, who were subdivided into three groups
(young (YO) n=33, 24.7±3.5 years; middle age (MA) n=15, 58.6±4.2 years; and
older adults (OA). n=15, 72.0±4.2 years). Isometric strength was recorded
simultaneously with the capture of the electrical activity of the flexor
muscles of the fingers and the vastus lateralis during handgrip and knee
extension tests, respectively. FFM was assessed using dual-energy X-ray
absorptiometry. Results The handgrip strength measurements were similar among groups (p=0.523),
whereas the FFM of the upper limbs was lower in group OA compared to group
YO (p=0.108). The RMSn values of the hand flexors were similar among groups
(p=0.754). However, the strength of the knee extensors, the FFM of the lower
limbs and the RMSn values of the vastus lateralis were lower in groups MA
(p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and
p<0.000, respectively) compared to group YO. Conclusions The results of this study demonstrate that changes in isometric muscle
strength in MLG and electromyographic activity of the lower limbs are more
pronounced with the aging process of the upper limb.
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Affiliation(s)
- Josária F Amaral
- School of Physical Therapy, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Felipe C Alvim
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Eliane A Castro
- Department of Physical Education, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Leonice A Doimo
- Department of Physical Education, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Marcus V Silva
- School of Physical Therapy, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil
| | - José M Novo Júnior
- Department of Physical Education, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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66
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Abstract
Movement is accomplished by the controlled activation of motor unit populations. Our understanding of motor unit physiology has been derived from experimental work on the properties of single motor units and from computational studies that have integrated the experimental observations into the function of motor unit populations. The article provides brief descriptions of motor unit anatomy and muscle unit properties, with more substantial reviews of motoneuron properties, motor unit recruitment and rate modulation when humans perform voluntary contractions, and the function of an entire motor unit pool. The article emphasizes the advances in knowledge on the cellular and molecular mechanisms underlying the neuromodulation of motoneuron activity and attempts to explain the discharge characteristics of human motor units in terms of these principles. A major finding from this work has been the critical role of descending pathways from the brainstem in modulating the properties and activity of spinal motoneurons. Progress has been substantial, but significant gaps in knowledge remain.
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Affiliation(s)
- C J Heckman
- Northwestern University, Evanston, Illinois, USA.
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67
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Ferreira ADS, Guimarães FS, Magalhães MAR, Silva RCSE. Accuracy and learning curves of inexperienced observers for manual segmentation of electromyograms. FISIOTERAPIA EM MOVIMENTO 2013. [DOI: 10.1590/s0103-51502013000300009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: The shape-varying format of surface electromyograms introduces errors in the detection of contraction events. OBJECTIVE: To investigate the accuracy and learning curves of inexperienced observers to detect the quantity of contraction events in surface electromyograms. MATERIALS AND METHODS: Six observers performed manual segmentation in 1200 shape-varying waveforms simulated using a phenomenological model with variable events, smooth changes in amplitude, marked on-off timing, and variable signal-to-noise ratio (0-39 dB). Segmentation was organized in four sessions with 15 blocks of 20 signals each. Accuracy and learning curves were modeled per block by linear and power regression models and tested for difference among sessions. Cut-off values of signal-to-noise ratio for optimal manual segmentation were also estimated. RESULTS: The accuracy curve showed no significant linear trend throughout blocks and no difference among sessions 1-2-3-4 (87% [85; 89], 87% [85; 89], 87% [85; 89], 87% [81; 88]; p = 0.691). Accuracy was low for detection of 1 event (AUC = 0.40; sensitivity = 44%; specificity = 43%; cut-off = 12.9 dB) but was high and affected by the signal-to-noise ratio for detection of two events (AUC = 0.82; sensitivity = 77%; specificity = 76%; cut-off = 7.0 dB). The learning curve showed a significant power regression (p < 0.001) with decreasing values of learning percentages (time duration to complete the task) among sessions 1-2-3-4 (86.5% [68; 94], 76% [68; 91], 62% [38; 77], and 57% [52; 75]; p = 0.002). CONCLUSION: Inexperienced observers exhibit high, not trainable accuracy and a practice-dependent shortening in the time spent to detect the quantity of contraction events in simulated surface electromyograms.
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68
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Lee SSM, Arnold AS, Miara MDB, Biewener AA, Wakeling JM. Accuracy of gastrocnemius muscles forces in walking and running goats predicted by one-element and two-element Hill-type models. J Biomech 2013; 46:2288-95. [PMID: 23871235 DOI: 10.1016/j.jbiomech.2013.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 06/05/2013] [Accepted: 06/09/2013] [Indexed: 10/26/2022]
Abstract
Hill-type models are commonly used to estimate muscle forces during human and animal movement-yet the accuracy of the forces estimated during walking, running, and other tasks remains largely unknown. Further, most Hill-type models assume a single contractile element, despite evidence that faster and slower motor units, which have different activation-deactivation dynamics, may be independently or collectively excited. This study evaluated a novel, two-element Hill-type model with "differential" activation of fast and slow contractile elements. Model performance was assessed using a comprehensive data set (including measures of EMG intensity, fascicle length, and tendon force) collected from the gastrocnemius muscles of goats during locomotor experiments. Muscle forces predicted by the new two-element model were compared to the forces estimated using traditional one-element models and to the forces measured in vivo using tendon buckle transducers. Overall, the two-element model resulted in the best predictions of in vivo gastrocnemius force. The coefficient of determination, r(2), was up to 26.9% higher and the root mean square error, RMSE, was up to 37.4% lower for the two-element model than for the one-element models tested. All models captured salient features of the measured muscle force during walking, trotting, and galloping (r(2)=0.26-0.51), and all exhibited some errors (RMSE=9.63-32.2% of the maximum in vivo force). These comparisons provide important insight into the accuracy of Hill-type models. The results also show that incorporation of fast and slow contractile elements within muscle models can improve estimates of time-varying, whole muscle force during locomotor tasks.
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Affiliation(s)
- Sabrina S M Lee
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
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69
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Kamavuako EN, Scheme EJ, Englehart KB. Wrist torque estimation during simultaneous and continuously changing movements: surface vs. untargeted intramuscular EMG. J Neurophysiol 2013; 109:2658-65. [PMID: 23515790 DOI: 10.1152/jn.00086.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this paper, the predictive capability of surface and untargeted intramuscular electromyography (EMG) was compared with respect to wrist-joint torque to quantify which type of measurement better represents joint torque during multiple degrees-of-freedom (DoF) movements for possible application in prosthetic control. Ten able-bodied subjects participated in the study. Surface and intramuscular EMG was recorded concurrently from the right forearm. The subjects were instructed to track continuous contraction profiles using single and combined DoF in two trials. The association between torque and EMG was assessed using an artificial neural network. Results showed a significant difference between the two types of EMG (P < 0.007) for all performance metrics: coefficient of determination (R(2)), Pearson correlation coefficient (PCC), and root mean square error (RMSE). The performance of surface EMG (R(2) = 0.93 ± 0.03; PCC = 0.98 ± 0.01; RMSE = 8.7 ± 2.1%) was found to be superior compared with intramuscular EMG (R(2) = 0.80 ± 0.07; PCC = 0.93 ± 0.03; RMSE = 14.5 ± 2.9%). The higher values of PCC compared with R(2) indicate that both methods are able to track the torque profile well but have some trouble (particularly intramuscular EMG) in estimating the exact amplitude. The possible cause for the difference, thus the low performance of intramuscular EMG, may be attributed to the very high selectivity of the recordings used in this study.
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Affiliation(s)
- Ernest N Kamavuako
- Center for SMI, Dept. of HST, Aalborg Univ., Fredrik Bajers Vej 7 D3, DK-9220 Aalborg, Denmark.
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70
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Lohse KR, Sherwood DE. Thinking about muscles: the neuromuscular effects of attentional focus on accuracy and fatigue. Acta Psychol (Amst) 2012; 140:236-45. [PMID: 22683497 DOI: 10.1016/j.actpsy.2012.05.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 05/04/2012] [Accepted: 05/15/2012] [Indexed: 11/18/2022] Open
Abstract
Although the effects of attention on movement execution are well documented behaviorally, much less research has been done on the neurophysiological changes that underlie attentional focus effects. This study presents two experiments exploring effects of attention during an isometric plantar-flexion task using surface electromyography (sEMG). Participants' attention was directed either externally (towards the force plate they were pushing against) or internally (towards their own leg, specifically the agonist muscle). Experiment 1 tested the effects of attention on accuracy and efficiency of force produced at three target forces (30, 60, and 100% of the maximum voluntary contraction; MVC). An internal focus of attention reduced the accuracy of force being produced and increased cocontraction of the antagonist muscle. Error on a given trial was positively correlated with the magnitude of cocontraction on that trial. Experiment 2 tested the effects of attention on muscular fatigue at 30, 60 and 100%MVC. An internal focus of attention led to less efficient intermuscular coordination, especially early in the contraction. These results suggest that an internal focus of attention disrupts efficient motor control in force production resulting in increased cocontraction, which potentially explains other neuromechanical findings (e.g. reduced functional variability with an internal focus).
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Affiliation(s)
- Keith R Lohse
- Department of Psychology and Neuroscience, University of Colorado, Boulder, 345 UCB, Boulder, CO 80309, USA.
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71
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Christodoulou C, Kaplanis P, Murray V, Pattichis M, Pattichis C, Kyriakides T. Multi-scale AM–FM analysis for the classification of surface electromyographic signals. Biomed Signal Process Control 2012. [DOI: 10.1016/j.bspc.2012.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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72
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Li X, Rymer WZ, Zhou P. A simulation-based analysis of motor unit number index (MUNIX) technique using motoneuron pool and surface electromyogram models. IEEE Trans Neural Syst Rehabil Eng 2012; 20:297-304. [PMID: 22514208 PMCID: PMC3556460 DOI: 10.1109/tnsre.2012.2194311] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Motor unit number index (MUNIX) measurement has recently achieved increasing attention as a tool to evaluate the progression of motoneuron diseases. In our current study, the sensitivity of the MUNIX technique to changes in motoneuron and muscle properties was explored by a simulation approach utilizing variations on published motoneuron pool and surface electromyogram (EMG) models. Our simulation results indicate that, when keeping motoneuron pool and muscle parameters unchanged and varying the input motor unit numbers to the model, then MUNIX estimates can appropriately characterize changes in motor unit numbers. Such MUNIX estimates are not sensitive to different motor unit recruitment and rate coding strategies used in the model. Furthermore, alterations in motor unit control properties do not have a significant effect on the MUNIX estimates. Neither adjustment of the motor unit recruitment range nor reduction of the motor unit firing rates jeopardizes the MUNIX estimates. The MUNIX estimates closely correlate with the maximum M-wave amplitude. However, if we reduce the amplitude of each motor unit action potential rather than simply reduce motor unit number, then MUNIX estimates substantially underestimate the motor unit numbers in the muscle. These findings suggest that the current MUNIX definition is most suitable for motoneuron diseases that demonstrate secondary evidence of muscle fiber reinnervation. In this regard, when MUNIX is applied, it is of much importance to examine a parallel measurement of motor unit size index (MUSIX), defined as the ratio of the maximum M-wave amplitude to the MUNIX. However, there are potential limitations in the application of the MUNIX methods in atrophied muscle, where it is unclear whether the atrophy is accompanied by loss of motor units or loss of muscle fiber size.
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Affiliation(s)
- Xiaoyan Li
- Sensory Motor Performance Program (SMPP) of the Rehabilitation Institute of Chicago, Chicago, 60611, USA
| | - William Zev Rymer
- SMPP of the Rehabilitation Institute of Chicago, and Departments of Physical Medicine and Rehabilitation, Physiology, and Biomedical Engineering of Northwestern University, Chicago, 60611, USA
| | - Ping Zhou
- SMPP of the Rehabilitation Institute of Chicago, and Department of Physical Medicine and Rehabilitation of Northwestern University, Chicago, 60611, USA, and the Institute of Biomedical Engineering of the University of Science and Technology of China, Hefei, China, phone: 01-312-238-1365
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73
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A muscle's force depends on the recruitment patterns of its fibers. Ann Biomed Eng 2012; 40:1708-20. [PMID: 22350666 DOI: 10.1007/s10439-012-0531-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 02/08/2012] [Indexed: 10/28/2022]
Abstract
Biomechanical models of whole muscles commonly used in simulations of musculoskeletal function and movement typically assume that the muscle generates force as a scaled-up muscle fiber. However, muscles are comprised of motor units that have different intrinsic properties and that can be activated at different times. This study tested whether a muscle model comprised of motor units that could be independently activated resulted in more accurate predictions of force than traditional Hill-type models. Forces predicted by the models were evaluated by direct comparison with the muscle forces measured in situ from the gastrocnemii in goats. The muscle was stimulated tetanically at a range of frequencies, muscle fiber strains were measured using sonomicrometry, and the activation patterns of the different types of motor unit were calculated from electromyographic recordings. Activation patterns were input into five different muscle models. Four models were traditional Hill-type models with different intrinsic speeds and fiber-type properties. The fifth model incorporated differential groups of fast and slow motor units. For all goats, muscles and stimulation frequencies the differential model resulted in the best predictions of muscle force. The in situ muscle output was shown to depend on the recruitment of different motor units within the muscle.
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74
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Thongpanja S, Phinyomark A, Phukpattaranont P, Limsakul C. A Feasibility Study of Fatigue and Muscle Contraction Indices Based on EMG Time-dependent Spectral Analysis. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.proeng.2012.01.1263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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75
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Farina D, Negro F. Accessing the Neural Drive to Muscle and Translation to Neurorehabilitation Technologies. IEEE Rev Biomed Eng 2012; 5:3-14. [DOI: 10.1109/rbme.2012.2183586] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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76
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McChesney BD, Haig L, Gissane C. The effect of thoracic spine high-velocity low-amplitude thrust manipulation on myoelectric activity of the lower trapezius and posterior deltoid muscles during treadmill walking. INT J OSTEOPATH MED 2011. [DOI: 10.1016/j.ijosm.2011.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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77
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Effects of monopolar and bipolar electrode configurations on surface EMG spike analysis. Med Eng Phys 2011; 33:1079-85. [DOI: 10.1016/j.medengphy.2011.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 04/12/2011] [Accepted: 04/23/2011] [Indexed: 11/17/2022]
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78
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A spectral analysis of rotator cuff musculature electromyographic activity: surface and indwelling. HSS J 2011; 7:21-8. [PMID: 22294954 PMCID: PMC3026106 DOI: 10.1007/s11420-010-9178-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 06/22/2010] [Indexed: 02/07/2023]
Abstract
Electromyography (EMG) of the shoulder girdle is commonly performed; however, EMG spectral properties of shoulder muscles have not been clearly defined. The purpose of this study was to determine the maximum power frequency, Nyquist rate, and minimum sampling rate for indwelling and surface EMG of the normal shoulder girdle musculature. EMG signals were recorded using indwelling electrodes for the rotator cuff muscles and surface electrodes for ten additional shoulder muscles in ten healthy volunteers. A fast Fourier transform was performed on the raw EMG signal collected during maximal isometric contractions to derive the power spectral density. The 95% power frequency was calculated during the ramp and plateau subphase of each contraction. Data were analyzed with analysis of variance (ANOVA) and paired t tests. Indwelling EMG signals had more than twice the frequency content of surface EMG signals (p < .001). Mean 95% power frequencies ranged from 495 to 560 Hz for indwelling electrodes and from 152 to 260 Hz for surface electrodes. Significant differences in the mean 95% power frequencies existed among muscles monitored with surface electrodes (p = .002), but not among muscles monitored with indwelling electrodes (p = .961). No significant differences in the 95% power frequencies existed among contraction subphases for any of the muscle-electrode combinations. Maximum Nyquist rate was 893 Hz for surface electrodes and 1,764 Hz for indwelling electrodes. Our results suggest that when recording EMG of shoulder muscles, the minimum sampling frequency is 1,340 Hz for surface electrodes and 2,650 Hz for indwelling electrodes. The minimum sampling recommendations are higher than the 1,000 Hz reported in many studies involving EMG of the shoulder.
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79
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Leporace G, Pereira GR, Nadal J, Batista LA. Differences in time-frequency representation of lower limbs myoelectric activity during single and double leg landing in male athletes. J Electromyogr Kinesiol 2011; 21:506-11. [PMID: 21195629 DOI: 10.1016/j.jelekin.2010.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/28/2010] [Accepted: 12/02/2010] [Indexed: 11/26/2022] Open
Abstract
This study compared the instantaneous median frequency (IMF) obtained by means of a Choi-Williams transform of an electromyogram of the lower-limb muscles during single-leg (SL) and double-leg (DL) landings performed by fifteen male athletes. The IMF values of the rectus femoris (RF), biceps femoris (BF) and hip adductors (HA) were compared between two landing tasks, within each landing, and before and after ground contact (GC). The IMF values of the RF did not change between landings in contrast to those of the BF, which presented from 20- to 40-ms higher SL values before GC and from 40 to 60 ms after GC. HA presented higher SL values during the 40-60 ms range before GC. Within each landing, the RF IMF decreased from 40 ms to 60 ms after GC in the SL. Similar results were found for the HA IMF, which decreased from 40ms to 80 ms after GC. The BF IMF showed no significant change. These results suggest muscle recruitment related to anterior cruciate ligament protection since the IMF values of the RF decreased in the SL, whereas the BF IMF increased. Results for the HA showed the importance of hip muscles in stabilizing the core region, allowing the activation of distal muscles with greater safety.
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Affiliation(s)
- Gustavo Leporace
- Laboratory of Biomechanics and Motor Behavior, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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80
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81
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Gabriel DA, Christie A, Inglis JG, Kamen G. Experimental and modelling investigation of surface EMG spike analysis. Med Eng Phys 2010; 33:427-37. [PMID: 21146442 DOI: 10.1016/j.medengphy.2010.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 10/27/2010] [Accepted: 11/12/2010] [Indexed: 11/15/2022]
Abstract
A pattern classification method based on five measures extracted from the surface electromyographic (sEMG) signal is used to provide a unique characterization of the interference pattern for different motor unit behaviours. This study investigated the sensitivity of the five sEMG measures during the force gradation process. Tissue and electrode filtering effects were further evaluated using a sEMG model. Subjects (N=8) performed isometric elbow flexion contractions from 0 to 100% MVC. The sEMG signals from the biceps brachii were recorded simultaneously with force. The basic building block of the sEMG model was the detection of single fibre action potentials (SFAPs) through a homogeneous, equivalent isotropic, infinite volume conduction medium. The SFAPs were summed to generate single motor unit action potentials. The physiologic properties from a well-known muscle model and motor unit recruitment and firing rate schemes were combined to generate synthetic sEMG signals. The following pattern classification measures were calculated: mean spike amplitude, mean spike frequency, mean spike slope, mean spike duration, and the mean number of peaks per spike. Root-mean-square amplitude and mean power frequency were also calculated. Taken together, the experimental data and modelling analysis showed that below 50% MVC, the pattern classification measures were more sensitive to changes in force than traditional time and frequency measures. However, there are additional limitations associated with electrode distance from the source that must be explored further. Future experimental work should ensure that the inter-electrode distance is no greater than 1cm to mitigate the effects of tissue filtering.
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Affiliation(s)
- David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON, Canada L2S 3A1.
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82
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Stirn I, Jarm T, Kapus V, Strojnik V. Evaluation of muscle fatigue during 100-m front crawl. Eur J Appl Physiol 2010; 111:101-13. [DOI: 10.1007/s00421-010-1624-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2010] [Indexed: 11/24/2022]
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83
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Lenti M, De Vito G, Sbriccoli P, Scotto di Palumbo A, Sacchetti M. Muscle fibre conduction velocity and cardiorespiratory response during incremental cycling exercise in young and older individuals with different training status. J Electromyogr Kinesiol 2010; 20:566-71. [DOI: 10.1016/j.jelekin.2010.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/26/2010] [Accepted: 02/10/2010] [Indexed: 11/17/2022] Open
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84
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Navallas J, Malanda A, Gila L, Rodríguez J, Rodríguez I. A muscle architecture model offering control over motor unit fiber density distributions. Med Biol Eng Comput 2010; 48:875-86. [PMID: 20535575 DOI: 10.1007/s11517-010-0642-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 05/13/2010] [Indexed: 11/29/2022]
Abstract
The aim of this study was to develop a muscle architecture model able to account for the observed distributions of innervation ratios and fiber densities of different types of motor units in a muscle. A model algorithm is proposed and mathematically analyzed in order to obtain an inverse procedure that allows, by modification of input parameters, control over the output distributions of motor unit fiber densities. The model's performance was tested with independent data from a glycogen depletion study of the medial gastrocnemius of the rat. Results show that the model accurately reproduces the observed physiological distributions of innervation ratios and fiber densities and their relationships. The reliability and accuracy of the new muscle architecture model developed here can provide more accurate models for the simulation of different electromyographic signals.
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Affiliation(s)
- Javier Navallas
- Department of Electric and Electronic Engineering, Public University of Navarra, Pamplona, Navarra, Spain.
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85
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Madeleine P. On functional motor adaptations: from the quantification of motor strategies to the prevention of musculoskeletal disorders in the neck-shoulder region. Acta Physiol (Oxf) 2010; 199 Suppl 679:1-46. [PMID: 20579000 DOI: 10.1111/j.1748-1716.2010.02145.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Occupations characterized by a static low load and by repetitive actions show a high prevalence of work-related musculoskeletal disorders (WMSD) in the neck-shoulder region. Moreover, muscle fatigue and discomfort are reported to play a relevant initiating role in WMSD. AIMS To investigate relationships between altered sensory information, i.e. localized muscle fatigue, discomfort and pain and their associations to changes in motor control patterns. MATERIALS & METHODS In total 101 subjects participated. Questionnaires, subjective assessments of perceived exertion and pain intensity as well as surface electromyography (SEMG), mechanomyography (MMG), force and kinematics recordings were performed. RESULTS Multi-channel SEMG and MMG revealed that the degree of heterogeneity of the trapezius muscle activation increased with fatigue. Further, the spatial organization of trapezius muscle activity changed in a dynamic manner during sustained contraction with acute experimental pain. A graduation of the motor changes in relation to the pain stage (acute, subchronic and chronic) and work experience were also found. The duration of the work task was shorter in presence of acute and chronic pain. Acute pain resulted in decreased activity of the painful muscle while in subchronic and chronic pain, a more static muscle activation was found. Posture and movement changed in the presence of neck-shoulder pain. Larger and smaller sizes of arm and trunk movement variability were respectively found in acute pain and subchronic/chronic pain. The size and structure of kinematics variability decreased also in the region of discomfort. Motor variability was higher in workers with high experience. Moreover, the pattern of activation of the upper trapezius muscle changed when receiving SEMG/MMG biofeedback during computer work. DISCUSSION SEMG and MMG changes underlie functional mechanisms for the maintenance of force during fatiguing contraction and acute pain that may lead to the widespread pain seen in WMSD. A lack of harmonious muscle recruitment/derecruitment may play a role in pain transition. Motor behavior changed in shoulder pain conditions underlining that motor variability may play a role in the WMSD development as corroborated by the changes in kinematics variability seen with discomfort. This prognostic hypothesis was further, supported by the increased motor variability among workers with high experience. CONCLUSION Quantitative assessments of the functional motor adaptations can be a way to benchmark the pain status and help to indentify signs indicating WMSD development. Motor variability is an important characteristic in ergonomic situations. Future studies will investigate the potential benefit of inducing motor variability in occupational settings.
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Affiliation(s)
- P Madeleine
- Laboratory for Ergonomics and Work-related Disorders, Department of Health Science and Technology, Aalborg University, Center for Sensory-Motor Interaction, Aalborg, Denmark.
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86
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Suzuki E, Ishigaki S, Yatani H, Morishige E, Uchida M. Mean power frequency during speech in myalgia patients. J Oral Rehabil 2010; 37:692-7. [PMID: 20492433 DOI: 10.1111/j.1365-2842.2010.02101.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The purpose of this study was to clarify a difference of mean power frequency (MPF) during speech between control and myalgia patients groups. The control group consisted of 20 asymptomatic volunteers and the myalgia patients group consisted of 19 patients. A bilateral electromyogram (EMG) of masseter muscles during speech movement was recorded using surface electrodes, and the EMG data were stored and analysed with a computer-based EMG analyzer. The MPF during the entire duration of EMG burst during speech was compared between the control and myalgia group. The average (SD) MPFs during speech in the myalgia and control groups were 214.06 (17.23) and 183.39 (22.35) Hz, respectively, significantly higher in the former (P < 0.001). In myalgia patients, firing rates or recruitment of motor units innervated by high threshold motoneurons might decrease and lead to a higher MPF. The result suggests the possibility that muscle pain, that is a subjective experience, could be evaluated by objective data that is calculated from electromyographic activities which is recorded during speech.
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Affiliation(s)
- E Suzuki
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
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87
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Orizio C, Baruzzi E, Gaffurini P, Diemont B, Gobbo M. Electromyogram and force fluctuation during different linearly varying isometric motor tasks. J Electromyogr Kinesiol 2010; 20:732-41. [PMID: 20395156 DOI: 10.1016/j.jelekin.2010.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 03/12/2010] [Accepted: 03/17/2010] [Indexed: 12/14/2022] Open
Abstract
The purpose of this work was to verify if deviation from the mirror-like behaviour of the motor units activation strategy (MUAS) and de-activation strategy (MUDS) and the degree of the error of the motor control system, during consecutive linearly increasing-decreasing isometric tension tasks, depend on the maximum reached tension and/or on the rate of tension changes. In 12 male subjects the surface EMG and force produced by the first dorsal interosseus activity were recorded during two (a and b) trapezoid isometric contractions with different plateau (a: 50% maximal voluntary contraction (MVC) and b: 100% MVC) and rate of tension changes (a: 6.7% MVC/s and b: 13.3% MVC/s) during up-going (UGR) and down-going (DGR) ramps. Ten steps (ST) 6s long at 5, 10, 20, 30, 40, 50, 60, 70, 80 and 90% MVC were also recorded. The root mean square (RMS) and mean frequency (MF) from EMG and the relative error of actual force output with respect to the target (% ERR) were computed. The EMG-RMS/% MVC and EMG-MF/% MVC relationships were not overlapped when the ST and DGR as well as the UGR and DGR data were compared. The % ERR/% MVC relationships during a and b contractions differed from ST data only below 20% MVC. It can be concluded that MUAS and MUDS are not mirroring one each other because MU recruitment or de-recruitment threshold may be influenced by the maximum effort and by the % MVC/s of UGR and DGR. The role of MUs mechanical and/or central nervous system hysteresis on force decrement control is discussed.
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Affiliation(s)
- C Orizio
- Department of Biomedical Sciences and Biotechnologies, University of Brescia, Viale Europa 11, Brescia, Italy.
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88
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TILLIN NEALEA, JIMENEZ-REYES PEDRO, PAIN MATTHEWTG, FOLLAND JONATHANP. Neuromuscular Performance of Explosive Power Athletes versus Untrained Individuals. Med Sci Sports Exerc 2010; 42:781-90. [DOI: 10.1249/mss.0b013e3181be9c7e] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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89
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90
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Neto OP, Christou EA. Rectification of the EMG signal impairs the identification of oscillatory input to the muscle. J Neurophysiol 2009; 103:1093-103. [PMID: 20032241 DOI: 10.1152/jn.00792.2009] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rectification of EMG signals is a common processing step used when performing electroencephalographic-electromyographic (EEG-EMG) coherence and EMG-EMG coherence. It is well known, however, that EMG rectification alters the power spectrum of the recorded EMG signal (interference EMG). The purpose of this study was to determine whether rectification of the EMG signal influences the capability of capturing the oscillatory input to a single EMG signal and the common oscillations between two EMG signals. Several EMG signals were reconstructed from experimentally recorded EMG signals from the surface of the first dorsal interosseus muscle and were manipulated to have an oscillatory input or common input (for pairs of reconstructed EMG signals) at various frequency bands (in Hz: 0-12, 12-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, and 300-400), one at a time. The absolute integral and normalized integral of power, peak power, and peak coherence (for pairs of EMG signals) were quantified from each frequency band. The power spectrum of the interference EMG accurately detected the changes to the oscillatory input to the reconstructed EMG signal, whereas the power spectrum of the rectified EMG did not. Similarly, the EMG-EMG coherence between two interference EMG signals accurately detected the common input to the pairs of reconstructed EMG signals, whereas the EMG-EMG coherence between two rectified EMG signals did not. The frequency band from 12 to 30 Hz in the power spectrum of the rectified EMG and the EMG-EMG coherence between two rectified signals was influenced by the input from 100 to 150 Hz but not from the input from 12 to 30 Hz. The study concludes that the power spectrum of the EMG and EMG-EMG coherence should be performed on interference EMG signals and not on rectified EMG signals because rectification impairs the identification of the oscillatory input to a single EMG signal and the common oscillatory input between two EMG signals.
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Affiliation(s)
- Osmar Pinto Neto
- Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843-4243, USA
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91
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Marusiak J, Jaskólska A, Kisiel-Sajewicz K, Yue GH, Jaskólski A. EMG and MMG activities of agonist and antagonist muscles in Parkinson’s disease patients during absolute submaximal load holding. J Electromyogr Kinesiol 2009; 19:903-14. [DOI: 10.1016/j.jelekin.2008.03.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 03/03/2008] [Accepted: 03/11/2008] [Indexed: 10/22/2022] Open
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92
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Marusiak J, Jaskólska A, Jarocka E, Najwer W, Kisiel-Sajewicz K, Jaskólski A. Electromyography and mechanomyography of elbow agonists and antagonists in Parkinson disease. Muscle Nerve 2009; 40:240-8. [PMID: 19472352 DOI: 10.1002/mus.21250] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of this study was to assess the electromyographic (EMG) and mechanomyographic (MMG) activities of agonist and antagonist muscles in Parkinson disease patients during maximal isometric elbow contraction in flexion and extension. Ten elderly females with Parkinson disease (average age 75 years) and 10 age-matched healthy females were tested. The torque and the EMG and MMG signals from biceps brachii and triceps brachii were recorded during sustained maximal voluntary isometric contraction of the elbow flexors and extensors. There were no intergroup differences in the EMG and MMG activities of agonist and antagonist muscles or in torque. This might be because the Parkinson subjects were tested during their medication "ON" phase, or perhaps maximal isometric contraction (MVC) induced greater active muscle stiffness that affected the MMG signal. Muscle Nerve 40: 240-248, 2009.
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Affiliation(s)
- Jarosław Marusiak
- Department of Kinesiology, Faculty of Physiotherapy, University School of Physical Education, Al. Paderewskiego 35, Building P4, Wroclaw 51-612, Poland
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93
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Navallas J, Malanda A, Gila L, Rodriguez J, Rodriguez I. Comparative evaluation of motor unit architecture models. Med Biol Eng Comput 2009; 47:1131-42. [DOI: 10.1007/s11517-009-0526-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 08/03/2009] [Indexed: 11/27/2022]
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94
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Watanabe K, Akima H. Cross-talk from adjacent muscle has a negligible effect on surface electromyographic activity of vastus intermedius muscle during isometric contraction. J Electromyogr Kinesiol 2009; 19:e280-9. [DOI: 10.1016/j.jelekin.2008.06.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 05/23/2008] [Accepted: 06/06/2008] [Indexed: 11/26/2022] Open
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95
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Changes in interstitial noradrenaline, trapezius muscle activity and oxygen saturation during low-load work and recovery. Eur J Appl Physiol 2009; 107:31-42. [DOI: 10.1007/s00421-009-1095-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2009] [Indexed: 10/20/2022]
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96
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Cifrek M, Medved V, Tonković S, Ostojić S. Surface EMG based muscle fatigue evaluation in biomechanics. Clin Biomech (Bristol, Avon) 2009; 24:327-40. [PMID: 19285766 DOI: 10.1016/j.clinbiomech.2009.01.010] [Citation(s) in RCA: 355] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 02/07/2023]
Abstract
In the last three decades it has become quite common to evaluate local muscle fatigue by means of surface electromyographic (sEMG) signal processing. A large number of studies have been performed yielding signal-based quantitative criteria of fatigue in primarily static but also in dynamic tasks. The non-invasive nature of this approach has been particularly appealing in areas like ergonomics and occupational biomechanics, to name just the most prominent ones. However, a correct appreciation of the findings concerned can only be obtained by judging both the scientific value and practical utility of methods while appreciating the corresponding advantages and limitations. The aim of this paper is to serve as a state of the art summary of this issue. The paper gives an overview of classical and modern signal processing methods and techniques from the standpoint of applicability to sEMG signals in fatigue-inducing situations relevant to the broad field of biomechanics. Time domain, frequency domain, time-frequency and time-scale representations, and other methods such as fractal analysis and recurrence quantification analysis are described succinctly and are illustrated with their biomechanical applications, research or clinical alike. Examples from the authors' own work are incorporated where appropriate. The future of this methodology is projected by estimating those methods that have the greatest chance to be routinely used as reliable muscle fatigue measures.
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Affiliation(s)
- Mario Cifrek
- Faculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, HR-10000 Zagreb, Croatia.
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97
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Liebermann DG, Defrin R. Characteristics of the nociceptive withdrawal response elicited under aware and unaware conditions. J Electromyogr Kinesiol 2009; 19:e114-22. [DOI: 10.1016/j.jelekin.2007.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 10/12/2007] [Accepted: 10/12/2007] [Indexed: 11/26/2022] Open
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98
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A method for better positioning bipolar electrodes for lower limb EMG recordings during dynamic contractions. J Neurosci Methods 2009; 180:133-7. [PMID: 19427540 DOI: 10.1016/j.jneumeth.2009.02.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 02/22/2009] [Accepted: 02/23/2009] [Indexed: 11/24/2022]
Abstract
To obtain a high quality EMG acquisition, the signal must be recorded as far away as possible from muscle innervations and tendon zones, which are known to shift during dynamic contractions. This study describes a methodology, using commercial bipolar electrodes, to identify better electrode positions for superficial EMG of lower limb muscles during dynamic contractions. Eight female volunteers participated in this study. Myoelectric signals of the vastus lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles were acquired during maximum isometric contractions using bipolar electrodes. The electrode positions of each muscle were selected assessing SENIAM and then, other positions were located along the length of muscle up and down the SENIAM site. The raw signal (density), the linear envelopes, the RMS value, the motor point site, the position of the IZ and its shift during dynamic contractions were taken into account to select and compare electrode positions. For vastus lateralis and peroneus longus, the best sites were 66% and 25% of muscle length, respectively (similar to SENIAM location). The position of the tibialis anterior electrodes presented the best signal at 47.5% of its length (different from SENIAM location). The position of the gastrocnemius medialis electrodes was at 38% of its length and SENIAM does not specify a precise location for signal acquisition. The proposed method should be considered as another methodological step in every EMG study to guarantee the quality of the signal and subsequent human movement interpretations.
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99
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Judkins TN, Oleynikov D, Stergiou N. Electromyographic response is altered during robotic surgical training with augmented feedback. J Biomech 2009; 42:71-6. [DOI: 10.1016/j.jbiomech.2008.09.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 09/30/2008] [Accepted: 09/30/2008] [Indexed: 11/28/2022]
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100
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Falla D, Farina D, Kanstrup Dahl M, Graven-Nielsen T. Pain-induced changes in cervical muscle activation do not affect muscle fatigability during sustained isometric contraction. J Electromyogr Kinesiol 2008; 18:938-46. [PMID: 17632012 DOI: 10.1016/j.jelekin.2007.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/30/2007] [Accepted: 05/30/2007] [Indexed: 11/20/2022] Open
Abstract
This study investigated whether pain-induced changes in cervical muscle activation affect myoelectric manifestations of cervical muscle fatigue. Surface EMG signals were detected from the sternocleidomastoid and splenius capitis muscles bilaterally from 14 healthy subjects during 20-s cervical flexion contractions at 25% of the maximal force. Measurements were performed before and after the injection of 0.5 ml of hypertonic (painful) or isotonic (control) saline into either the sternocleidomastoid or splenius capitis in two experimental sessions. EMG average rectified value and mean power spectral frequency were estimated throughout the sustained contraction. Sternocleidomastoid or splenius capitis muscle pain resulted in lower sternocleidomastoid EMG average rectified value on the side of pain (P < 0.01). However, changes over time of sternocleidomastoid EMG average rectified value and mean frequency (myoelectric manifestations of fatigue) during sustained flexion were not changed during muscle pain. These results demonstrate that pain-induced modifications of cervical muscle activity do not change myoelectric manifestations of fatigue. This finding has implications for interpreting the mechanisms underlying greater cervical muscle fatigue in people with neck pain disorders.
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Affiliation(s)
- Deborah Falla
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, D-3, DK-9220 Aalborg, Denmark.
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