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Sample records for surface electromyographic emg

  1. Surface Electromyographic Sensor for Human Motion Estimation Based on Arm Wrestling Robot

    Directory of Open Access Journals (Sweden)

    Zhen GAO

    2010-06-01

    Full Text Available In this paper, the surface electromyographic (EMG sensor is developed to acquire the EMG signals from the upper limb when the participants compete with the arm wrestling robot (AWR which is fabricated to play arm wrestling game with human on a table with pegs for entertainment and human motion modeling of upper limbs muscle. As the EMG signal is a measurement of the anatomical and physiological characteristic of the specific muscle, the macroscopical movement patterns of the human body can be classified and recognized. The high-frequency noises are eliminated effectively and the characteristics of EMG signals can be extracted through wavelet packet transformation. Auto-regressive model of EMG is conducted to effectively simulate the stochastic time sequences with a series of auto-regressive coefficients. The win/lose pattern is recognized by neural network based on extracted characteristics of surface EMG signal.

  2. Predicting 3D lip shapes using facial surface EMG

    NARCIS (Netherlands)

    Eskes, Merijn; van Alphen, Maarten J. A.; Balm, Alfons J. M.; Smeele, Ludi E.; Brandsma, Dieta; van der Heijden, Ferdinand

    2017-01-01

    Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and

  3. Surface EMG measurements during fMRI at 3T : Accurate EMG recordings after artifact correction

    NARCIS (Netherlands)

    van Duinen, Hiske; Zijdewind, Inge; Hoogduin, H; Maurits, N

    2005-01-01

    In this experiment, we have measured surface EMG of the first dorsal interosseus during predefined submaximal isometric contractions (5, 15, 30, 50, and 70% of maximal force) of the index finger simultaneously with fMRI measurements. Since we have used sparse sampling fMRI (3-s scanning; 2-s

  4. A comparison of the electromyographic activity (EMG of the muscles during the release phase of javelin throwing in disabled male world and paralympic champions

    Directory of Open Access Journals (Sweden)

    Heydar Sadeghi

    2016-09-01

    Full Text Available Background : The purpose of this study was to recognize the performance of the pectoralis major, anterior deltoid, and triceps muscles of the disabled male world and paralympic championsby the EMG. Materials and Methods: The electrical activity of the pectoralis major, anterior deltoid, and triceps muscles of 24 disabled Iranian male world and paralympic throwers in sitting and standing positions was recorded by a surface electromyographic device. To determine the significant differences of the sitting and standing classes, the statistics techniques of the One Way ANOVA and the independent t- test at the 0.05 sinificant level were administered to the recorded data. Results: The activity (amplitude of pectoralis major and anterior deltoid muscles of the participants differed significantly in the sitting classes. Also, the activity of triceps muscles in the standing classes and that of pectoralis major muscles of the sitting and standing classes while the amplitude of triceps muscles of sitting classes, pectoralis major and anterior deltoid muscles of the standing classes, and anterior deltoid and triceps muscles of both sitting and standing classes was not significantly different. (p<0.05. Conclusion: The means of all the variables in the sitting classes were more than those in the standing classes. The highest amplitude belonged to the anterior deltoid, pectoralis major and triceps muscles of the sitting classes, respectively. This is due to the disabled throwers’ paralysis in the sitting position compared with that of the throwers in standing positions. The comparison of the amplitude recorded by surface electromyography of the disabled throwers’ muscles in all classes showed that the pectoralis major, anterior deltoid, and triceps muscles have major roles in the disabled male world and paralympic champions’ throwing events.

  5. Predicting 3D lip shapes using facial surface EMG.

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    Merijn Eskes

    Full Text Available The aim of this study is to prove that facial surface electromyography (sEMG conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and their associated motions.With a stereo camera set-up, we recorded 3D lip shapes and simultaneously performed sEMG measurements of the facial muscles, applying principal component analysis (PCA and a modified general regression neural network (GRNN to link the sEMG measurements to 3D lip shapes. To test reproducibility, we conducted our experiment on five volunteers, evaluating several sEMG features and window lengths in unipolar and bipolar configurations in search of the optimal settings for facial sEMG.The errors of the two methods were comparable. We managed to predict 3D lip shapes with a mean accuracy of 2.76 mm when using the PCA method and 2.78 mm when using modified GRNN. Whereas performance improved with shorter window lengths, feature type and configuration had little influence.

  6. Reliability of surface EMG measurements from the suprahyoid muscle complex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Stubbs, Peter William; Pedersen, Asger Roer

    2017-01-01

    of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Methods: Seventeen healthy participants were recruited. Measurements were performed twice with one week...... between sessions. Single pulse (at 120% and 140% of the resting motor threshold (rMT)) and paired pulse (2 ms and 15 ms paired pulse) transcranial magnetic stimulation (TMS) were used to elicit MEPs in the SMC which were recorded using sEMG. Results: ≈50% of participants (range: 42%-58%; depending...... on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single pulse and paired pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. Conclusions: The assessment of the SMC using sEMG following TMS was poorly...

  7. Recording and conditioning of surface EMG signal for decomposition

    Czech Academy of Sciences Publication Activity Database

    Pošusta, A.; Otáhal, Jakub

    2012-01-01

    Roč. 8, č. 30 (2012), s. 28-31 ISSN 1801-1217 R&D Projects: GA AV ČR(CZ) 1QS501210509; GA ČR(CZ) GBP304/12/G069 Grant - others:GA MŠk(CZ) LH12070 Institutional support: RVO:67985823 Keywords : surface electromyography * decomposition * EMG Lab * prosthetics Subject RIV: FH - Neurology

  8. Modeling dynamic high-DOF finger postures from surface EMG using nonlinear synergies in latent space representation.

    Science.gov (United States)

    Ngeo, Jimson; Tamei, Tomoya; Ikeda, Kazushi; Shibata, Tomohiro

    2015-01-01

    Accurate proportional myoelectric control of the hand is important in replicating dexterous manipulation in robot prostheses and orthoses. However, this is still difficult to achieve due to the complex and high degree-of-freedom (DOF) nature present in the governing musculoskeletal system. To address this problem, we suggest using a low dimensional encoding based on nonlinear synergies to represent both the high-DOF finger joint kinematics and the coordination of muscle activities taken from surface electromyographic (EMG) signals. Generating smooth multi-finger movements using EMG inputs is then done by using a shared Gaussian Process latent variable model that learns a dynamical model between both the kinematic and EMG data represented in a shared latent space. The experimental results show that the method is able to synthesize continuous movements of a full five-finger hand model, with total dimensions as large as 69 (although highly redundant and correlated). Finally, by comparing the estimation performances when the number of EMG latent dimensions are varied, we show that these synergistic features can capture the variance, shared and specific to the observed kinematics.

  9. Muscle-tendon units localization and activation level analysis based on high-density surface EMG array and NMF algorithm

    Science.gov (United States)

    Huang, Chengjun; Chen, Xiang; Cao, Shuai; Zhang, Xu

    2016-12-01

    Objective. Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task. Approach. Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied. Eight healthy male subjects participated in the data collection experiments, and 128-channel surface electromyographic (sEMG) signals were collected with a high-density sEMG electrode grid (a grid consists of 8 rows and 16 columns). Then the sEMG envelopes matrix was factorized into a matrix of weighting vectors and a matrix of time-varying coefficients by nonnegative matrix factorization algorithm. Main results. The experimental results demonstrated that the weightings vectors, which represent invariant pattern of muscle activity across all channels, could be used to estimate the location of MTUs and the time-varying coefficients could be used to depict the variation of MTUs activation level during dynamic motion task. Significance. The proposed method provides one way to analyze in-depth the functional state of MTUs during dynamic tasks and thus can be employed on multiple noteworthy sEMG-based applications such as muscle force estimation, muscle fatigue research and the control of myoelectric prostheses. This work was supported by the National Nature Science Foundation of China under Grant 61431017 and 61271138.

  10. Surface EMG-based Sketching Recognition Using Two Analysis Windows and Gene Expression Programming

    Science.gov (United States)

    Yang, Zhongliang; Chen, Yumiao

    2016-01-01

    Sketching is one of the most important processes in the conceptual stage of design. Previous studies have relied largely on the analyses of sketching process and outcomes; whereas surface electromyographic (sEMG) signals associated with sketching have received little attention. In this study, we propose a method in which 11 basic one-stroke sketching shapes are identified from the sEMG signals generated by the forearm and upper arm muscles from 4 subjects. Time domain features such as integrated electromyography, root mean square and mean absolute value were extracted with analysis windows of two length conditions for pattern recognition. After reducing data dimensionality using principal component analysis, the shapes were classified using Gene Expression Programming (GEP). The performance of the GEP classifier was compared to the Back Propagation neural network (BPNN) and the Elman neural network (ENN). Feature extraction with the short analysis window (250 ms with a 250 ms increment) improved the recognition rate by around 6.4% averagely compared with the long analysis window (2500 ms with a 2500 ms increment). The average recognition rate for the eleven basic one-stroke sketching patterns achieved by the GEP classifier was 96.26% in the training set and 95.62% in the test set, which was superior to the performance of the BPNN and ENN classifiers. The results show that the GEP classifier is able to perform well with either length of the analysis window. Thus, the proposed GEP model show promise for recognizing sketching based on sEMG signals. PMID:27790083

  11. Surface EMG in advanced hand prosthetics.

    Science.gov (United States)

    Castellini, Claudio; van der Smagt, Patrick

    2009-01-01

    One of the major problems when dealing with highly dexterous, active hand prostheses is their control by the patient wearing them. With the advances in mechatronics, building prosthetic hands with multiple active degrees of freedom is realisable, but actively controlling the position and especially the exerted force of each finger cannot yet be done naturally. This paper deals with advanced robotic hand control via surface electromyography. Building upon recent results, we show that machine learning, together with a simple downsampling algorithm, can be effectively used to control on-line, in real time, finger position as well as finger force of a highly dexterous robotic hand. The system determines the type of grasp a human subject is willing to use, and the required amount of force involved, with a high degree of accuracy. This represents a remarkable improvement with respect to the state-of-the-art of feed-forward control of dexterous mechanical hands, and opens up a scenario in which amputees will be able to control hand prostheses in a much finer way than it has so far been possible.

  12. Prediction of Above-elbow Motions in Amputees, based on Electromyographic(EMG Signals, Using Nonlinear Autoregressive Exogenous (NARX Model

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    Ali Akbar Akbari

    2014-08-01

    Full Text Available Introduction In order to improve the quality of life of amputees, biomechatronic researchers and biomedical engineers have been trying to use a combination of various techniques to provide suitable rehabilitation systems. Diverse biomedical signals, acquired from a specialized organ or cell system, e.g., the nervous system, are the driving force for the whole system. Electromyography(EMG, as an experimental technique,is concerned with the development, recording, and analysis of myoelectric signals. EMG-based research is making progress in the development of simple, robust, user-friendly, and efficient interface devices for the amputees. Materials and Methods Prediction of muscular activity and motion patterns is a common, practical problem in prosthetic organs. Recurrent neural network (RNN models are not only applicable for the prediction of time series, but are also commonly used for the control of dynamical systems. The prediction can be assimilated to identification of a dynamic process. An architectural approach of RNN with embedded memory is Nonlinear Autoregressive Exogenous (NARX model, which seems to be suitable for dynamic system applications. Results Performance of NARX model is verified for several chaotic time series, which are applied as input for the neural network. The results showed that NARX has the potential to capture the model of nonlinear dynamic systems. The R-value and MSE are  and  , respectively. Conclusion  EMG signals of deltoid and pectoralis major muscles are the inputs of the NARX  network. It is possible to obtain EMG signals of muscles in other arm motions to predict the lost functions of the absent arm in above-elbow amputees, using NARX model.

  13. Electromyographic Grasp Recognition for a Five Fingered Robotic Hand

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    Nayan M. Kakoty

    2012-09-01

    Full Text Available This paper presents classification of grasp types based on surface electromyographic signals. Classification is through radial basis function kernel support vector machine using sum of wavelet decomposition coefficients of the EMG signals. In a study involving six subjects, we achieved an average recognition rate of 86%. The electromyographic grasp recognition together with a 8-bit microcontroller has been employed to control a fivefingered robotic hand to emulate six grasp types used during 70% daily living activities.

  14. Histamine induced airway response in pre-school children assessed by a non-invasive EMG technique

    NARCIS (Netherlands)

    Maarsingh, E. J. W.; van Eykern, LA; Sprikkelman, AB; van Aalderen, WMC

    The aim of the study was to investigate the association between surface electromyographic (EMG) activity of the diaphragm and intercostal muscles, and clinical symptoms (wheeze, cough, increased respiratory rate and prolonged expiration) during bronchial challenge testing and after administration of

  15. Interpreting Changes in Surface EMG Amplitude During High-Level Fatiguing Contractions of the Brachioradialis

    National Research Council Canada - National Science Library

    Lowery, M

    2001-01-01

    ... to estimate muscle fatigue. In this paper, theoretical relationships between surface EMG amplitude measures and mean motor unit firing rates and muscle fiber conduction velocity (MFCV) are established...

  16. Motor unit action potential conduction velocity estimated from surface electromyographic signals using image processing techniques.

    Science.gov (United States)

    Soares, Fabiano Araujo; Carvalho, João Luiz Azevedo; Miosso, Cristiano Jacques; de Andrade, Marcelino Monteiro; da Rocha, Adson Ferreira

    2015-09-17

    In surface electromyography (surface EMG, or S-EMG), conduction velocity (CV) refers to the velocity at which the motor unit action potentials (MUAPs) propagate along the muscle fibers, during contractions. The CV is related to the type and diameter of the muscle fibers, ion concentration, pH, and firing rate of the motor units (MUs). The CV can be used in the evaluation of contractile properties of MUs, and of muscle fatigue. The most popular methods for CV estimation are those based on maximum likelihood estimation (MLE). This work proposes an algorithm for estimating CV from S-EMG signals, using digital image processing techniques. The proposed approach is demonstrated and evaluated, using both simulated and experimentally-acquired multichannel S-EMG signals. We show that the proposed algorithm is as precise and accurate as the MLE method in typical conditions of noise and CV. The proposed method is not susceptible to errors associated with MUAP propagation direction or inadequate initialization parameters, which are common with the MLE algorithm. Image processing -based approaches may be useful in S-EMG analysis to extract different physiological parameters from multichannel S-EMG signals. Other new methods based on image processing could also be developed to help solving other tasks in EMG analysis, such as estimation of the CV for individual MUs, localization and tracking of innervation zones, and study of MU recruitment strategies.

  17. A Variance Distribution Model of Surface EMG Signals Based on Inverse Gamma Distribution.

    Science.gov (United States)

    Hayashi, Hideaki; Furui, Akira; Kurita, Yuichi; Tsuji, Toshio

    2017-11-01

    Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this variance. Variance distribution estimation based on marginal likelihood maximization is also outlined in this paper. The procedure can be approximated using rectified and smoothed EMG signals, thereby allowing the determination of distribution parameters in real time at low computational cost. Results: A simulation experiment was performed to evaluate the accuracy of distribution estimation using artificially generated EMG signals, with results demonstrating that the proposed model's accuracy is higher than that of maximum-likelihood-based estimation. Analysis of variance distribution using real EMG data also suggested a relationship between variance distribution and signal-dependent noise. Conclusion: The study reported here was conducted to examine the performance of a proposed surface EMG model capable of representing variance distribution and a related distribution parameter estimation method. Experiments using artificial and real EMG data demonstrated the validity of the model. Significance: Variance distribution estimated using the proposed model exhibits potential in the estimation of muscle force. Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this

  18. Comparison of hamstring and quadriceps femoris electromyographic activity between men and women during a single-limb squat on both a stable and labile surface.

    Science.gov (United States)

    Youdas, James W; Hollman, John H; Hitchcock, James R; Hoyme, Gregory J; Johnsen, Jeremiah J

    2007-02-01

    The purpose of this study was to determine if women are quadriceps dominant and men are hamstring dominant during the performance of a partial single-leg squat (SLS) on both a stable and labile ground surface against body weight resistance. Thirty healthy participants (15 men and 15 women) performed an SLS on both a stable surface and a 6.4-cm-thick vinyl pad. Surface electromyographic (EMG) recordings were obtained from the quadriceps femoris and hamstring muscles during the extension phase of the SLS. Statistical analysis revealed that women produced 14% more EMG activity (p = 0.04) in their quadriceps than the men during the SLS on a stable surface, whereas the men generated 18% more EMG activity (p = 0.04) in their hamstrings than the women during the SLS on a labile surface. Additionally, we found a statistically significant sex effect (p = 0.048) for the hamstring/quadriceps (H/Q) EMG ratio, which was 2.25 and 0.62, respectively, for men and women on the stable surface and 2.52 and 0.71, respectively, on the labile surface. We concluded that women are quadriceps dominant and men are hamstring dominant during the performance of SLS against body weight resistance on either a stable or labile surface condition. During an SLS, men showed an H/Q ratio approximately 3.5 times larger than their female counterparts, suggesting that men activate their hamstrings more effectively than women during an SLS. According to our data, the SLS may not be an ideal exercise for activating the hamstring muscles in women without additional neuromuscular training techniques, because women are quadriceps dominant during the SLS.

  19. Effect of Vibration Training on Anaerobic Power and Quardroceps Surface EMG in Long Jumpers

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    Liu, Bin; Luo, Jiong

    2015-01-01

    Objective: To explore the anaerobic power and surface EMG (sEMG) of quardrocep muscle in lower extremities after single vibration training intervention. Methods: 8 excellent male long jumpers voluntarily participated in this study. Four intervention modes were devised, including high frequency high amplitude (HFHA,30Hz,6mm), low frequency low…

  20. Estimation of Upper Limb Joint Angle Using Surface EMG Signal

    Directory of Open Access Journals (Sweden)

    Yee Mon Aung

    2013-10-01

    Full Text Available In the development of robot-assisted rehabilitation systems for upper limb rehabilitation therapy, human electromyogram (EMG is widely used due to its ability to detect the user intended motion. EMG is one kind of biological signal that can be recorded to evaluate the performance of skeletal muscles by means of a sensor electrode. Based on recorded EMG signals, user intended motion could be extracted via estimation of joint torque, force or angle. Therefore, this estimation becomes one of the most important factors to achieve accurate user intended motion. In this paper, an upper limb joint angle estimation methodology is proposed. A back propagation neural network (BPNN is developed to estimate the shoulder and elbow joint angles from the recorded EMG signals. A Virtual Human Model (VHM is also developed and integrated with BPNN to perform the simulation of the estimated angle. The relationships between sEMG signals and upper limb movements are observed in this paper. The effectiveness of our developments is evaluated with four healthy subjects and a VHM simulation. The results show that the methodology can be used in the estimation of joint angles based on EMG.

  1. Long-term surface EMG monitoring using K-means clustering and compressive sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    In this work, we present an advanced K-means clustering algorithm based on Compressed Sensing theory (CS) in combination with the K-Singular Value Decomposition (K-SVD) method for Clustering of long-term recording of surface Electromyography (sEMG) signals. The long-term monitoring of sEMG signals aims at recording of the electrical activity produced by muscles which are very useful procedure for treatment and diagnostic purposes as well as for detection of various pathologies. The proposed algorithm is examined for three scenarios of sEMG signals including healthy person (sEMG-Healthy), a patient with myopathy (sEMG-Myopathy), and a patient with neuropathy (sEMG-Neuropathr), respectively. The proposed algorithm can easily scan large sEMG datasets of long-term sEMG recording. We test the proposed algorithm with Principal Component Analysis (PCA) and Linear Correlation Coefficient (LCC) dimensionality reduction methods. Then, the output of the proposed algorithm is fed to K-Nearest Neighbours (K-NN) and Probabilistic Neural Network (PNN) classifiers in order to calclute the clustering performance. The proposed algorithm achieves a classification accuracy of 99.22%. This ability allows reducing 17% of Average Classification Error (ACE), 9% of Training Error (TE), and 18% of Root Mean Square Error (RMSE). The proposed algorithm also reduces 14% clustering energy consumption compared to the existing K-Means clustering algorithm.

  2. Neuromuscular functions in sportsmen and fibromyalgia patients : a surface EMG study in static and dynamic conditions

    NARCIS (Netherlands)

    Klaver-Krol, E.G.

    2012-01-01

    This thesis presents two studies, one involving sportsmen (sprinters versus endurance athletes) and one fibromyalgia patients (patients versus healthy controls). The studies have investigated muscular functions using a non-invasive method: surface electromyography (sEMG). In the sportsmen,

  3. Three-Dimensional Model of a Muscle and Simulation of its Surface EMG

    National Research Council Canada - National Science Library

    Schnetzer, M

    2001-01-01

    ...) and a simulation of its surface EMG. The simulations are part of a larger model including in addition the input system to the motoneuronal pool, the motoneuronal pool itself and the force generating mechanism...

  4. A Novel Hybrid Model for Drawing Trace Reconstruction from Multichannel Surface Electromyographic Activity.

    Science.gov (United States)

    Chen, Yumiao; Yang, Zhongliang

    2017-01-01

    Recently, several researchers have considered the problem of reconstruction of handwriting and other meaningful arm and hand movements from surface electromyography (sEMG). Although much progress has been made, several practical limitations may still affect the clinical applicability of sEMG-based techniques. In this paper, a novel three-step hybrid model of coordinate state transition, sEMG feature extraction and gene expression programming (GEP) prediction is proposed for reconstructing drawing traces of 12 basic one-stroke shapes from multichannel surface electromyography. Using a specially designed coordinate data acquisition system, we recorded the coordinate data of drawing traces collected in accordance with the time series while 7-channel EMG signals were recorded. As a widely-used time domain feature, Root Mean Square (RMS) was extracted with the analysis window. The preliminary reconstruction models can be established by GEP. Then, the original drawing traces can be approximated by a constructed prediction model. Applying the three-step hybrid model, we were able to convert seven channels of EMG activity recorded from the arm muscles into smooth reconstructions of drawing traces. The hybrid model can yield a mean accuracy of 74% in within-group design (one set of prediction models for all shapes) and 86% in between-group design (one separate set of prediction models for each shape), averaged for the reconstructed x and y coordinates. It can be concluded that it is feasible for the proposed three-step hybrid model to improve the reconstruction ability of drawing traces from sEMG.

  5. Force control is related to low-frequency oscillations in force and surface EMG.

    Directory of Open Access Journals (Sweden)

    Hwasil Moon

    Full Text Available Force variability during constant force tasks is directly related to oscillations below 0.5 Hz in force. However, it is unknown whether such oscillations exist in muscle activity. The purpose of this paper, therefore, was to determine whether oscillations below 0.5 Hz in force are evident in the activation of muscle. Fourteen young adults (21.07 ± 2.76 years, 7 women performed constant isometric force tasks at 5% and 30% MVC by abducting the left index finger. We recorded the force output from the index finger and surface EMG from the first dorsal interosseous (FDI muscle and quantified the following outcomes: 1 variability of force using the SD of force; 2 power spectrum of force below 2 Hz; 3 EMG bursts; 4 power spectrum of EMG bursts below 2 Hz; and 5 power spectrum of the interference EMG from 10-300 Hz. The SD of force increased significantly from 5 to 30% MVC and this increase was significantly related to the increase in force oscillations below 0.5 Hz (R(2 = 0.82. For both force levels, the power spectrum for force and EMG burst was similar and contained most of the power from 0-0.5 Hz. Force and EMG burst oscillations below 0.5 Hz were highly coherent (coherence = 0.68. The increase in force oscillations below 0.5 Hz from 5 to 30% MVC was related to an increase in EMG burst oscillations below 0.5 Hz (R(2 = 0.51. Finally, there was a strong association between the increase in EMG burst oscillations below 0.5 Hz and the interference EMG from 35-60 Hz (R(2 = 0.95. In conclusion, this finding demonstrates that bursting of the EMG signal contains low-frequency oscillations below 0.5 Hz, which are associated with oscillations in force below 0.5 Hz.

  6. Integration of surface electromyographic sensors with the transfemoral amputee socket: a comparison of four differing configurations.

    Science.gov (United States)

    Hefferman, Gerald M; Zhang, Fan; Nunnery, Michael J; Huang, He

    2015-04-01

    In recent years, there has been an increased interest in recording high-quality electromyographic signals from within the sockets of lower-limb amputees. However, successful recording presents major challenges to both researchers and clinicians. This article details and compares four prototypical integrated socket-sensor designs used to record electromyographic signals from within the sockets of transfemoral amputees. Four prototypical socket-sensor configurations were constructed and tested on a single transfemoral amputee asked to perform sitting/standing, stair ascent/descent, and level ground walking. The number of large-amplitude motion artifacts generated using each prototype was quantified, the amount of skin irritation documented, and the comfort level of each assembly subjectively assessed by the amputee subject. Of the four configurations tested, the combination of a suction socket with integrated wireless surface electrodes generated the lowest number of large-amplitude motion artifacts, the least visible skin irritation, and was judged to be most comfortable by the amputee subject. The collection of high-quality electromyographic signals from an amputee's residual limb while maximizing patient comfort holds substantial potential to enhance neuromuscular clinical assessment and as a method of intuitive control of powered lower-limb prostheses. © The International Society for Prosthetics and Orthotics 2014.

  7. Recognition and prediction of individual and combined muscular activation modes via surface EMG analysis

    Directory of Open Access Journals (Sweden)

    Daniel Graupe

    2010-09-01

    Full Text Available The paper discusses how recognition of individual and combined muscular activation modes (functions and the prediction of intended such modes can be accomplished by identifying parameters of noninvasive surface EMG signals. It outlines the mathematical analysis of surface EMG signal to facilitate such recognition and related prediction, including recognition of intention (in terms of attempts to activate motor functions from the EMG, without accessing the CNS itself, in cases where a patient, say, a high-level amputee does not have the final-activation muscles and joints. The EMG activity thus allows to interpret and recognize CNS commands from minute variations in the parameters of surface EMG signals that record changes in the firing of motor neurons triggering contractions in related muscle fibers. We note that although in popular media this is sometimes referred to as detection of “thoughts”, no thoughts are detected, but only motor-outcomes of thoughts as found in the EMG signal. Examples of concrete cases where such recognition or prediction were accomplished in the author’s lab and in devices that came out of that lab, are given as are references to these in the literature over the last 35 years.

  8. Surface EMG decomposition based on K-means clustering and convolution kernel compensation.

    Science.gov (United States)

    Ning, Yong; Zhu, Xiangjun; Zhu, Shanan; Zhang, Yingchun

    2015-03-01

    A new approach has been developed by combining the K-mean clustering (KMC) method and a modified convolution kernel compensation (CKC) method for multichannel surface electromyogram (EMG) decomposition. The KMC method was first utilized to cluster vectors of observations at different time instants and then estimate the initial innervation pulse train (IPT). The CKC method, modified with a novel multistep iterative process, was conducted to update the estimated IPT. The performance of the proposed K-means clustering-Modified CKC (KmCKC) approach was evaluated by reconstructing IPTs from both simulated and experimental surface EMG signals. The KmCKC approach successfully reconstructed all 10 IPTs from the simulated surface EMG signals with true positive rates (TPR) of over 90% with a low signal-to-noise ratio (SNR) of -10 dB. More than 10 motor units were also successfully extracted from the 64-channel experimental surface EMG signals of the first dorsal interosseous (FDI) muscles when a contraction force was held at 8 N by using the KmCKC approach. A "two-source" test was further conducted with 64-channel surface EMG signals. The high percentage of common MUs and common pulses (over 92% at all force levels) between the IPTs reconstructed from the two independent groups of surface EMG signals demonstrates the reliability and capability of the proposed KmCKC approach in multichannel surface EMG decomposition. Results from both simulated and experimental data are consistent and confirm that the proposed KmCKC approach can successfully reconstruct IPTs with high accuracy at different levels of contraction.

  9. Effect of upper costal and costo-diaphragmatic breathing types on electromyographic activity of respiratory muscles.

    Science.gov (United States)

    Celhay, Isabel; Cordova, Rosa; Miralles, Rodolfo; Meza, Francisco; Erices, Pia; Barrientos, Camilo; Valenzuela, Saúl

    2015-04-01

    To compare electromyographic (EMG) activity in young-adult subjects with different breathing types. This study included 50 healthy male subjects with complete natural dentition, and no history of orofacial pain or craniomandibular-cervical-spinal disorders. Subjects were classified into two groups: upper costal breathing type, and costo-diaphragmatic breathing. Bipolar surface electrodes were located on sternocleidomastoid, diaphragm, external intercostal, and latissimus dorsi muscles. Electromyographic activity was recorded during the following tasks: (1) normal quiet breathing; (2) speaking the word 'Mississippi'; (3) swallowing saliva; and (4) forced deep breathing. Sternocleidomastoid and latissimus dorsi EMG activity was not significantly different between breathing types, whereas diaphragm and external intercostal EMG activity was significantly higher in the upper costal than costo-diaphragmatic breathing type in all tasks (P<0·05; Wilcoxon signed rank-sum test). Diaphragm and external intercostal EMG activity suggests that there could be differences in motor unit recruitment strategies depending on the breathing type.

  10. A comparison of surface and fine wire EMG recordings of gluteus medius during selected maximum isometric voluntary contractions of the hip.

    Science.gov (United States)

    Semciw, Adam I; Neate, Rachel; Pizzari, Tania

    2014-12-01

    Electromyographic (EMG) studies into gluteus medius (GMed) typically involve surface EMG electrodes. Previous comparisons of surface and fine wire electrode recordings in other muscles during high load isometric tasks suggest that recordings between electrodes are comparable when the muscle is contracting at a high intensity, however, surface electrodes record additional activity when the muscle is contracting at a low intensity. The purpose of this study was to compare surface and fine wire recordings of GMed at high and low intensities of muscle contractions, under high load conditions (maximum voluntary isometric contractions, MVICs). Mann-Whitney U tests compared median electrode recordings during three MVIC hip actions; abduction, internal rotation and external rotation, in nine healthy adults. There were no significant differences between electrode recordings in positions that evoked a high intensity contraction (internal rotation and abduction, fine wire activity >77% MVIC; effect size, ES0.277). During external rotation, the intensity of muscle activity was low (4.2% MVIC), and surface electrodes recorded additional myoelectric activity (ES=0.67, p=0.002). At low levels of muscle activity during high load isometric tasks, the use of surface electrodes may result in additional myoelectric recordings of GMed, potentially reflective of cross-talk from surrounding muscles. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  11. Electromyographic Analysis of the Lower Limb Muscles in Low- and High-Handicap Golfers

    Science.gov (United States)

    Marta, Sérgio; Silva, Luís; Vaz, João R.; Castro, Maria António; Reinaldo, Gustavo; Pezarat-Correia, Pedro

    2016-01-01

    Purpose: The aim of this study was to compare the electromyographic patterns of the lower limb muscles during a golf swing performed by low- and high-handicap golfers. Method: Ten golfers (5 low- and 5 high-handicap) performed 8 swings using a 7-iron. Surface electromyography (EMG) was recorded for the following lower limb muscles on both sides:…

  12. Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings.

    Science.gov (United States)

    Peng, Yun; He, Jinbao; Khavari, Rose; Boone, Timothy B; Zhang, Yingchun

    2016-11-01

    Knowledge of the innervation of pelvic floor and sphincter muscles is of great importance to understanding the pathophysiology of female pelvic floor dysfunctions. This report presents our high-density intravaginal and intrarectal electromyography (EMG) probes and a comprehensive innervation zone (IZ) imaging technique based on high-density EMG readings to characterize the IZ distribution. Both intravaginal and intrarectal probes are covered with a high-density surface electromyography electrode grid (8 × 8). Surface EMG signals were acquired in ten healthy women performing maximum voluntary contractions of their pelvic floor. EMG decomposition was performed to separate motor-unit action potentials (MUAPs) and then localize their IZs. High-density surface EMG signals were successfully acquired over the vaginal and rectal surfaces. The propagation patterns of muscle activity were clearly visualized for multiple muscle groups of the pelvic floor and anal sphincter. During each contraction, up to 218 and 456 repetitions of motor units were detected by the vaginal and rectal probes, respectively. MUAPs were separated with their IZs identified at various orientations and depths. The proposed probes are capable of providing a comprehensive mapping of IZs of the pelvic floor and sphincter muscles. They can be employed as diagnostic and preventative tools in clinical practices.

  13. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

    Directory of Open Access Journals (Sweden)

    Jinzhuang Xiao

    2016-01-01

    Full Text Available Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P>0.05 between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.

  14. Comparison of surface and intramuscular EMG pattern recognition for simultaneous wrist/hand motion classification.

    Science.gov (United States)

    Smith, Lauren H; Hargrove, Levi J

    2013-01-01

    The simultaneous control of multiple degrees of freedom (DOFs) is important for the intuitive, life-like control of artificial limbs. The objective of this study was to determine whether the use of intramuscular electromyogram (EMG) improved pattern classification of simultaneous wrist/hand movements compared to surface EMG. Two pattern classification methods were used in this analysis, and were trained to predict 1-DOF and 2-DOF movements involving wrist rotation, wrist flexion/extension, and hand open/close. The classification methods used were (1) a single pattern classifier discriminating between 1-DOF and 2-DOF motion classes, and (2) a parallel set of three classifiers to predict the activity of each of the 3 DOFs. We demonstrate that in this combined wrist/hand classification task, the use of intramuscular EMG significantly decreases classification error compared to surface EMG for the parallel configuration (p<0.01), but not for the single classifier. We also show that the use of intramuscular EMG mitigates the increase in errors produced when the parallel classifier method is trained without 2-DOF motion class data.

  15. Subspace based adaptive denoising of surface EMG from neurological injury patients

    Science.gov (United States)

    Liu, Jie; Ying, Dongwen; Zev Rymer, William; Zhou, Ping

    2014-10-01

    Objective: After neurological injuries such as spinal cord injury, voluntary surface electromyogram (EMG) signals recorded from affected muscles are often corrupted by interferences, such as spurious involuntary spikes and background noises produced by physiological and extrinsic/accidental origins, imposing difficulties for signal processing. Conventional methods did not well address the problem caused by interferences. It is difficult to mitigate such interferences using conventional methods. The aim of this study was to develop a subspace-based denoising method to suppress involuntary background spikes contaminating voluntary surface EMG recordings. Approach: The Karhunen-Loeve transform was utilized to decompose a noisy signal into a signal subspace and a noise subspace. An optimal estimate of EMG signal is derived from the signal subspace and the noise power. Specifically, this estimator is capable of making a tradeoff between interference reduction and signal distortion. Since the estimator partially relies on the estimate of noise power, an adaptive method was presented to sequentially track the variation of interference power. The proposed method was evaluated using both semi-synthetic and real surface EMG signals. Main results: The experiments confirmed that the proposed method can effectively suppress interferences while keep the distortion of voluntary EMG signal in a low level. The proposed method can greatly facilitate further signal processing, such as onset detection of voluntary muscle activity. Significance: The proposed method can provide a powerful tool for suppressing background spikes and noise contaminating voluntary surface EMG signals of paretic muscles after neurological injuries, which is of great importance for their multi-purpose applications.

  16. Real-time intelligent pattern recognition algorithm for surface EMG signals

    Directory of Open Access Journals (Sweden)

    Jahed Mehran

    2007-12-01

    Full Text Available Abstract Background Electromyography (EMG is the study of muscle function through the inquiry of electrical signals that the muscles emanate. EMG signals collected from the surface of the skin (Surface Electromyogram: sEMG can be used in different applications such as recognizing musculoskeletal neural based patterns intercepted for hand prosthesis movements. Current systems designed for controlling the prosthetic hands either have limited functions or can only be used to perform simple movements or use excessive amount of electrodes in order to achieve acceptable results. In an attempt to overcome these problems we have proposed an intelligent system to recognize hand movements and have provided a user assessment routine to evaluate the correctness of executed movements. Methods We propose to use an intelligent approach based on adaptive neuro-fuzzy inference system (ANFIS integrated with a real-time learning scheme to identify hand motion commands. For this purpose and to consider the effect of user evaluation on recognizing hand movements, vision feedback is applied to increase the capability of our system. By using this scheme the user may assess the correctness of the performed hand movement. In this work a hybrid method for training fuzzy system, consisting of back-propagation (BP and least mean square (LMS is utilized. Also in order to optimize the number of fuzzy rules, a subtractive clustering algorithm has been developed. To design an effective system, we consider a conventional scheme of EMG pattern recognition system. To design this system we propose to use two different sets of EMG features, namely time domain (TD and time-frequency representation (TFR. Also in order to decrease the undesirable effects of the dimension of these feature sets, principle component analysis (PCA is utilized. Results In this study, the myoelectric signals considered for classification consists of six unique hand movements. Features chosen for EMG signal

  17. Surface EMG signals based motion intent recognition using multi-layer ELM

    Science.gov (United States)

    Wang, Jianhui; Qi, Lin; Wang, Xiao

    2017-11-01

    The upper-limb rehabilitation robot is regard as a useful tool to help patients with hemiplegic to do repetitive exercise. The surface electromyography (sEMG) contains motion information as the electric signals are generated and related to nerve-muscle motion. These sEMG signals, representing human's intentions of active motions, are introduced into the rehabilitation robot system to recognize upper-limb movements. Traditionally, the feature extraction is an indispensable part of drawing significant information from original signals, which is a tedious task requiring rich and related experience. This paper employs a deep learning scheme to extract the internal features of the sEMG signals using an advanced Extreme Learning Machine based auto-encoder (ELMAE). The mathematical information contained in the multi-layer structure of the ELM-AE is used as the high-level representation of the internal features of the sEMG signals, and thus a simple ELM can post-process the extracted features, formulating the entire multi-layer ELM (ML-ELM) algorithm. The method is employed for the sEMG based neural intentions recognition afterwards. The case studies show the adopted deep learning algorithm (ELM-AE) is capable of yielding higher classification accuracy compared to the Principle Component Analysis (PCA) scheme in 5 different types of upper-limb motions. This indicates the effectiveness and the learning capability of the ML-ELM in such motion intent recognition applications.

  18. Effectiveness of the Wavelet Transform on the Surface EMG to Understand the Muscle Fatigue During Walk

    Science.gov (United States)

    Hussain, M. S.; Mamun, Md.

    2012-01-01

    Muscle fatigue is the decline in ability of a muscle to create force. Electromyography (EMG) is a medical technique for measuring muscle response to nervous stimulation. During a sustained muscle contraction, the power spectrum of the EMG shifts towards lower frequencies. These effects are due to muscle fatigue. Muscle fatigue is often a result of unhealthy work practice. In this research, the effectiveness of the wavelet transform applied to the surface EMG (SEMG) signal as a means of understanding muscle fatigue during walk is presented. Power spectrum and bispectrum analysis on the EMG signal getting from right rectus femoris muscle is executed utilizing various wavelet functions (WFs). It is possible to recognize muscle fatigue appreciably with the proper choice of the WF. The outcome proves that the most momentous changes in the EMG power spectrum are symbolized by WF Daubechies45. Moreover, this research has compared bispectrum properties to the other WFs. To determine muscle fatigue during gait, Daubechies45 is used in this research to analyze the SEMG signal.

  19. Convolutive blind source separation of surface EMG measurements of the respiratory muscles.

    Science.gov (United States)

    Petersen, Eike; Buchner, Herbert; Eger, Marcus; Rostalski, Philipp

    2017-04-01

    Electromyography (EMG) has long been used for the assessment of muscle function and activity and has recently been applied to the control of medical ventilation. For this application, the EMG signal is usually recorded invasively by means of electrodes on a nasogastric tube which is placed inside the esophagus in order to minimize noise and crosstalk from other muscles. Replacing these invasive measurements with an EMG signal obtained non-invasively on the body surface is difficult and requires techniques for signal separation in order to reconstruct the contributions of the individual respiratory muscles. In the case of muscles with small cross-sectional areas, or with muscles at large distances from the recording site, solutions to this problem have been proposed previously. The respiratory muscles, however, are large and distributed widely over the upper body volume. In this article, we describe an algorithm for convolutive blind source separation (BSS) that performs well even for large, distributed muscles such as the respiratory muscles, while using only a small number of electrodes. The algorithm is derived as a special case of the TRINICON general framework for BSS. To provide evidence that it shows potential for separating inspiratory, expiratory, and cardiac activities in practical applications, a joint numerical simulation of EMG and ECG activities was performed, and separation success was evaluated in a variety of noise settings. The results are promising.

  20. Muscle fiber velocity and electromyographic signs of fatigue in fibromyalgia.

    Science.gov (United States)

    Klaver-Król, Ewa G; Rasker, Johannes J; Henriquez, Nizare R; Verheijen, Wilma G; Zwarts, Machiel J

    2012-11-01

    Fibromyalgia (FM) is a disorder of widespread muscular pain. We investigated possible differences in surface electromyography (sEMG) in clinically unaffected muscle between patients with FM and controls. sEMG was performed on the biceps brachii muscle of 13 women with FM and 14 matched healthy controls during prolonged dynamic exercises, unloaded, and loaded up to 20% of maximum voluntary contraction. The sEMG parameters were: muscle fiber conduction velocity (CV); skewness of motor unit potential (peak) velocities; peak frequency (PF) (number of peaks per second); and average rectified voltage (ARV). There was significantly higher CV in the FM group. Although the FM group performed the tests equally well, their electromyographic fatigue was significantly less expressed compared with controls (in CV, PF, and ARV). In the patients with FM, we clearly showed functional abnormalities of the muscle membrane, which led to high conduction velocity and resistance to fatigue in electromyography. Copyright © 2012 Wiley Periodicals, Inc.

  1. Comparison of EMG signals recorded by surface electrodes on endotracheal tube and thyroid cartilage during monitored thyroidectomy

    Directory of Open Access Journals (Sweden)

    Feng-Yu Chiang

    2017-10-01

    Full Text Available A variety of electromyography (EMG recording methods were reported during intraoperative neural monitoring (IONM of recurrent laryngeal nerve (RLN in thyroid surgery. This study compared two surface recording methods that were obtained by electrodes on endotracheal tube (ET and thyroid cartilage (TC. This study analyzed 205 RLNs at risk in 110 patients undergoing monitored thyroidectomy. Each patient was intubated with an EMG ET during general anesthesia. A pair of single needle electrode was inserted obliquely into the TC lamina on each side. Standard IONM procedure was routinely followed, and EMG signals recorded by the ET and TC electrodes at each step were compared. In all nerves, evoked laryngeal EMG signals were reliably recorded by the ET and TC electrodes, and showed the same typical waveform and latency. The EMG signals recorded by the TC electrodes showed significantly higher amplitudes and stability compared to those by the ET electrodes. Both recording methods accurately detected 7 partial loss of signal (LOS and 2 complete LOS events caused by traction stress, but only the ET electrodes falsely detected 3 LOS events caused by ET displacement during surgical manipulation. Two patients with true complete LOS experienced temporary RLN palsy postoperatively. Neither permanent RLN palsy, nor complications from ET or TC electrodes were encountered in this study. Both electrodes are effective and reliable for recording laryngeal EMG signals during monitored thyroidectomy. Compared to ET electrodes, TC electrodes obtain higher and more stable EMG signals as well as fewer false EMG results during IONM.

  2. The reliability of surface EMG recorded from the pelvic floor muscles.

    Science.gov (United States)

    Auchincloss, Cindy C; McLean, Linda

    2009-08-30

    The neuromuscular function of the pelvic floor muscles (PFMs) is frequently evaluated using surface electrodes embedded on vaginal probes. The purpose of this study was to determine the between-trial and between-day reliability of EMG data recorded from the PFM using two different vaginal probes while subjects performed PFM maximum voluntary contractions and a coughing task. The Femiscan and the Periform vaginal probes were used to acquire EMG data while the subjects performed the tasks. Peak RMS amplitudes were computed for each instrument, task, and side of the pelvic floor using a sliding window technique. The between-trial reliability was evaluated using intraclass correlation coefficients (ICCs) and coefficients of variation (CV). Between-trial reliability was determined using ICCs, Pearson's correlation coefficients, computing the mean absolute difference between days, and calculating the standard error the measurement (SEM) for each instrument and task. EMG amplitude differences were detected between the left and right PFM (pperformed separately for each side. Overall, between-trial reliability was fair to high for the Femiscan (ICC((3,1))=0.58-0.98, CV=8.5-20.7%) and good to high for the Periform (ICC((3,1))=0.80-0.98, CV=9.6-19.5%), however between-day reliability was generally poor for both vaginal probes (ICC((3,1))=0.08-0.84). The results suggest that although it is acceptable to use PFM surface EMG as a biofeedback tool for training purposes, it is not recommended for use to make between-subject comparisons or to use as an outcome measure between-days when evaluating PFM function.

  3. Onset Detection in Surface Electromyographic Signals: A Systematic Comparison of Methods

    Directory of Open Access Journals (Sweden)

    Claus Flachenecker

    2001-06-01

    Full Text Available Various methods to determine the onset of the electromyographic activity which occurs in response to a stimulus have been discussed in the literature over the last decade. Due to the stochastic characteristic of the surface electromyogram (SEMG, onset detection is a challenging task, especially in weak SEMG responses. The performance of the onset detection methods were tested, mostly by comparing their automated onset estimations to the manually determined onsets found by well-trained SEMG examiners. But a systematic comparison between methods, which reveals the benefits and the drawbacks of each method compared to the other ones and shows the specific dependence of the detection accuracy on signal parameters, is still lacking. In this paper, several classical threshold-based approaches as well as some statistically optimized algorithms were tested on large samples of simulated SEMG data with well-known signal parameters. Rating between methods is performed by comparing their performance to that of a statistically optimal maximum likelihood estimator which serves as reference method. In addition, performance was evaluated on real SEMG data obtained in a reaction time experiment. Results indicate that detection behavior strongly depends on SEMG parameters, such as onset rise time, signal-to-noise ratio or background activity level. It is shown that some of the threshold-based signal-power-estimation procedures are very sensitive to signal parameters, whereas statistically optimized algorithms are generally more robust.

  4. Self-Recalibrating Surface EMG Pattern Recognition for Neuroprosthesis Control Based on Convolutional Neural Network

    Directory of Open Access Journals (Sweden)

    Xiaolong Zhai

    2017-07-01

    Full Text Available Hand movement classification based on surface electromyography (sEMG pattern recognition is a promising approach for upper limb neuroprosthetic control. However, maintaining day-to-day performance is challenged by the non-stationary nature of sEMG in real-life operation. In this study, we propose a self-recalibrating classifier that can be automatically updated to maintain a stable performance over time without the need for user retraining. Our classifier is based on convolutional neural network (CNN using short latency dimension-reduced sEMG spectrograms as inputs. The pretrained classifier is recalibrated routinely using a corrected version of the prediction results from recent testing sessions. Our proposed system was evaluated with the NinaPro database comprising of hand movement data of 40 intact and 11 amputee subjects. Our system was able to achieve ~10.18% (intact, 50 movement types and ~2.99% (amputee, 10 movement types increase in classification accuracy averaged over five testing sessions with respect to the unrecalibrated classifier. When compared with a support vector machine (SVM classifier, our CNN-based system consistently showed higher absolute performance and larger improvement as well as more efficient training. These results suggest that the proposed system can be a useful tool to facilitate long-term adoption of prosthetics for amputees in real-life applications.

  5. Does Heel Height Cause Imbalance during Sit-to-Stand Task: Surface EMG Perspective

    Directory of Open Access Journals (Sweden)

    Ganesh R. Naik

    2017-08-01

    Full Text Available The purpose of this study was to determine whether electromyography (EMG muscle activities around the knee differ during sit-to-stand (STS and returning task for females wearing shoes with different heel heights. Sixteen healthy young women (age = 25.2 ± 3.9 years, body mass index = 20.8 ± 2.7 kg/m2 participated in this study. Electromyography signals were recorded from the two muscles, vastus medialis (VM and vastus lateralis (VL that involve in the extension of knee. The participants wore shoes with five different heights, including 4, 6, 8, 10, and 12 cm. Surface electromyography (sEMG data were acquired during STS and stand-to-sit-returning (STSR tasks. The data was filtered using a fourth order Butterworth (band pass filter of 20–450 Hz frequency range. For each heel height, we extracted median frequency (MDF and root mean square (RMS features to measure sEMG activities between VM and VL muscles. The experimental results (based on MDF and RMS-values indicated that there is imbalance between vasti muscles for more elevated heels. The results are also quantified with statistical measures. The study findings suggest that there would be an increased likelihood of knee imbalance and fatigue with regular usage of high heel shoes (HHS in women.

  6. Surface EMG of the masticatory muscles (part 2): fatigue testing, mastication analysis and influence of different factors.

    Science.gov (United States)

    Hugger, S; Schindler, H J; Kordass, B; Hugger, A

    2013-01-01

    The second part of this review of the literature on the clinical significance of surface electromyography (EMG) of the masticatory muscles systematically examines the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, investigating relevant aspects of EMG activity during prolonged chewing activity (fatigue effects), during the mastication process, and under the influence of different factors. Studies on the influence of factors such as gender, age, tooth status, orofacial morphology and (acute) pain, the significance of different occlusal relationships during static and dynamic occlusion, and the impact of changes in static occlusion on EMG activity of the masticatory muscles were included in the review.

  7. Assessment of Diaphragm and External Intercostals Fatigue from Surface EMG using Cervical Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Ya-Ju Chang

    2008-03-01

    Full Text Available This study was designed: (1 to test the reliability of surface electromyography (sEMG recording of the diaphragm and external intercostals contractions response to cervical magnetic stimulation (CMS, (2 to examine the amount and the types of inspiratory muscle fatigue that developed after maximum voluntary ventilation (MVV maneuvers.Ten male college students without physical disability (22.1±2.0 years old participated in the study and each completed a control (quiet breathing trial and a fatigue (MVV maneuvers trial sequentially. In the quiet breathing trial, the subjects maintained quiet breathing for five minutes. The subjects performed five maximal static inspiratory efforts and received five CMS before and after the quiet breathing. In the MVV trial, subjects performed five maximal inspiratory efforts and received five CMS before, immediately after, and ten minutes after two sets of MVV maneuvers performed five minutes apart. Maximal inspiratory pressure (PImax, sEMG of diaphragm and external intercostals during maximal static inspiratory efforts and during CMS were recorded. In the quiet breathing trial, high intraclass correlation coefficients (ICC=0.95-0.99 were observed in all the variables. In the MVV trial, the PImax, the EMG amplitude and the median power frequency during maximal static inspiratory efforts significantly decreased in both the diaphragm and the external intercostals immediately after the MVV maneuvers Sensors 2008, 8 2175 (P 0.05. It is concluded that the sEMG recordings of the diaphragm during maximal static inspiratory efforts and in response to CMS allow reproducible sequential assessment of diaphragm contractility. MVV maneuvers resulted in inspiratory muscles fatigue, possibly central fatigue.

  8. The effect of handedness on electromyographic activity of human shoulder muscles during movement

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

    2006-01-01

    The aim of the study was to investigate whether there was a difference in the electromyographic (EMG) activity of human shoulder muscles between the dominant and nondominant side during movement and to explore whether a possible side-difference depends on the specific task. We compared the EMG...... activity with surface and intramuscular electrodes in eight muscles of both shoulders in 20 healthy subjects whose hand preference was evaluated using a standard questionnaire. EMG signals were recorded during abduction and external rotation. During abduction, the normalized EMG activity was significantly...... smaller on the dominant side compared to the nondominant side for all the muscles except for infraspinatus and lower trapezius (P Udgivelsesdato: 2007-Aug...

  9. Comparison of trunk electromyographic muscle activity depends on sitting postures.

    Science.gov (United States)

    Lee, DongGeon; Yu, SeoJeong; Song, SunHae; Lee, Se-Han; An, SeungHeon; Cho, Hwi-Young; Cho, Ki-Hun; Lee, GyuChang

    2017-01-01

    Different postural positions can be characterized by the activation and relative contributions of different postural muscles, and may variously contribute to the recovery from or worsening of chronic lower back pain. The present study aimed to investigates trunk muscle activities in four types of seated postures: cross-legged, long, side, and W-shaped. Eight healthy adults participated in the study. Trunk muscle activities of the external oblique (EO), rectus abdominis (RA), latissimus dorsi (LD), and erector spinae (ES) muscles in each of the sitting postures including cross-legged, long, side, and W-shaped were collected utilizing surface electromyography (sEMG). The mean sEMG signals in each of the sitting postures were used for statistical comparisons. There were no significant differences in electromyographic muscle activity of EO, RA, LD, and ES in the four postures (p > 0.05). However, in the W-shape sitting posture, the left LD showed the greatest electromyographic muscle activity, followed by the right LD and left EO, respectively. The right and left LD in the long sitting posture and left ES in the side sitting posture showed greater electromyographic muscle activity than that of other muscles. Based on the results, trunk muscle activity did not significantly differ between the four types of sitting postures. However, our study is limited by its experimental method and sample size. Thus, in the Future, further study will be needed.

  10. Amplitude and frequency changes in surface EMG of biceps femoris during five days Bruce Protocol treadmill test.

    Science.gov (United States)

    Jamaluddin, Fauzani N; Ahmad, Siti A; Noor, Samsul Bahari Mohd; Hassan, Wan Zuha Wan; Yaakob, Azhar; Adam, Yunus; Ali, Sawal H M

    2015-01-01

    Electromyography (EMG) is one of the indirect tools in indexing fatigue. Fatigue can be detected when there are changes on amplitude and frequency. However, various outcomes from literature make researchers conclude that EMG is not a reliable tool to measure fatigue. This paper investigates EMG behavior of biceps femoris in median frequency and mean absolute value during five days of Bruce Protocol treadmill test. Before that, surface EMG signals are filtered using band pass filter cut-off at 20-500Hz and are de-noised using db45 1-decimated wavelet transform. Five participants achieved more than 85% of their maximal heart rate during the running activity. The authors also consider other markers of fatigue such as performance, muscle soreness and lethargy as indicators to adaptation and maladaptation conditions. Result shows that turning points of median frequency and mean absolute value are very significant in indexing fatigue and indicators to adaptation of resistive training.

  11. Electromyographic Analysis of the Triceps Surae Muscle Complex During Achilles Tendon Rehabilitation Program Exercises

    OpenAIRE

    Mullaney, Michael; Tyler, Timothy F.; McHugh, Malachy; Orishimo, Karl; Kremenic, Ian; Caggiano, Jessica; Ramsey, Abi

    2011-01-01

    Background: Specific guidelines for therapeutic exercises following an Achilles tendon repair are lacking. Hypothesis: A hierarchical progression of triceps surae exercises can be determined on the basis of electromyographic (EMG) activity. Study Design: Randomized laboratory trial. Methods: Bipolar surface electrodes were applied over the medial and lateral heads of the gastrocnemius as well as the soleus on 20 healthy lower extremities (10 participants, 27 ± 5 years old). Muscle activity wa...

  12. Surface EMG and intra-socket force measurement to control a prosthetic device

    Science.gov (United States)

    Sanford, Joe; Patterson, Rita; Popa, Dan

    2015-06-01

    Surface electromyography (SEMG) has been shown to be a robust and reliable interaction method allowing for basic control of powered prosthetic devices. Research has shown a marked decrease in EMG-classification efficiency throughout activities of daily life due to socket shift and movement and fatigue as well as changes in degree of fit of the socket throughout the subject's lifetime. Users with the most severe levels of amputation require the most complex devices with the greatest number of degrees of freedom. Controlling complex dexterous devices with limited available inputs requires the addition of sensing and interaction modalities. However, the larger the amputation severity, the fewer viable SEMG sites are available as control inputs. Previous work reported the use of intra-socket pressure, as measured during wrist flexion and extension, and has shown that it is possible to control a powered prosthetic device with pressure sensors. In this paper, we present data correlations of SEMG data with intra-socket pressure data. Surface EMG sensors and force sensors were housed within a simulated prosthetic cuff fit to a healthy-limbed subject. EMG and intra-socket force data was collected from inside the cuff as a subject performed pre-defined grip motions with their dominant hand. Data fusion algorithms were explored and allowed a subject to use both intra-socket pressure and SEMG data as control inputs for a powered prosthetic device. This additional input modality allows for an improvement in input classification as well as information regarding socket fit through out activities of daily life.

  13. Reliability of a combined biomechanical and surface electromyographical analysis system during dynamic barbell squat exercise.

    Science.gov (United States)

    Brandon, Raphael; Howatson, Glyn; Hunter, Angus

    2011-10-01

    An analysis system for barbell weightlifting exercises is proposed to record reliable performance and neuromuscular responses. The system consists of surface electromyography (sEMG) synchronized with electrogoniometry and a barbell position transducer. The purpose of this study was to establish the reliability of the three components of the system. Nine males (age 28.9 ± 4.8 years, mass 85.7 ± 15.1 kg) performed squat exercise at three loads on three separate trial days. A data acquisition and software system processed maximal knee angle (flexion), mean power for the concentric phase of squat exercise, and normalized root mean square of the vastus lateralis. Inter-trial coefficients of variation for each variable were calculated as 5.3%, 7.8%, and 7.5% respectively. In addition, knee joint motion and barbell displacement were significantly related to each other (bar displacement (m) = 1.39-0.0057 × knee angle (degress), with goodness-of-fit value, r² = 0.817), suggesting knee goniometry alone can represent the kinematics of a multi-joint squat exercise. The proven reliability of the three components of this system allows for real-time monitoring of resistance exercise using the preferred training methods of athletes, which could be valuable in the understanding of the neuromuscular response of elite strength training methods.

  14. The surface electromyographic evaluation of the Functional Reach in elderly subjects.

    Science.gov (United States)

    Maranesi, E; Fioretti, S; Ghetti, G G; Rabini, R A; Burattini, L; Mercante, O; Di Nardo, F

    2016-02-01

    This study proposes a comprehensive assessment of myoelectric activity of the main muscles involved in the Functional Reach (FR) test, in 24 elderly subjects. A specific protocol for the surface electromyography (sEMG) signal acquisition during FR-test was developed. Results show that anterior muscles activate following a caudo-cranial order. Tibialis Anterior (TA) is the first to be activated (-18.0±16.3% of the FR-period), together with Rectus Femoris (-10.4±17.9%). Then, Rectus Abdominis (19.7±24.7%) and Sternocleidomastoideus (19.9±15.6%) activate after the FR-start. Hamstrings, Soleus, and L4-level Erectores Spinae (posterior muscles) activate after the FR-start in this order (11.4±16.8%, 17.7±16.6%, and 35.2±29.0%, respectively) and remain active until the movement end. The analysis of the kinematic strategies adopted by subjects revealed an association between TA-activation patterns and two kinematic strategies (hip/mixed strategy), quantified by an increase (pelderly subjects, providing an early contribution in building a reference frame for balance assessment in clinical context. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Effective Low-Power Wearable Wireless Surface EMG Sensor Design Based on Analog-Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Mohammadreza Balouchestani

    2014-12-01

    Full Text Available Surface Electromyography (sEMG is a non-invasive measurement process that does not involve tools and instruments to break the skin or physically enter the body to investigate and evaluate the muscular activities produced by skeletal muscles. The main drawbacks of existing sEMG systems are: (1 they are not able to provide real-time monitoring; (2 they suffer from long processing time and low speed; (3 they are not effective for wireless healthcare systems because they consume huge power. In this work, we present an analog-based Compressed Sensing (CS architecture, which consists of three novel algorithms for design and implementation of wearable wireless sEMG bio-sensor. At the transmitter side, two new algorithms are presented in order to apply the analog-CS theory before Analog to Digital Converter (ADC. At the receiver side, a robust reconstruction algorithm based on a combination of ℓ1-ℓ1-optimization and Block Sparse Bayesian Learning (BSBL framework is presented to reconstruct the original bio-signals from the compressed bio-signals. The proposed architecture allows reducing the sampling rate to 25% of Nyquist Rate (NR. In addition, the proposed architecture reduces the power consumption to 40%, Percentage Residual Difference (PRD to 24%, Root Mean Squared Error (RMSE to 2%, and the computation time from 22 s to 9.01 s, which provide good background for establishing wearable wireless healthcare systems. The proposed architecture achieves robust performance in low Signal-to-Noise Ratio (SNR for the reconstruction process.

  16. Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by Volitional Activation of the Same Muscle

    DEFF Research Database (Denmark)

    Sennels, Søren; Biering-Sørensen, Fin; Andersen, Ole Trier

    1997-01-01

    In order to use the volitional electromyography (EMG) as a control signal for the stimulation of the same muscle, it is necessary to eliminate the stimulation artifacts and the muscle responses caused by the stimulation. The stimulation artifacts, caused by the electric field in skin and tissue....... For variations in shape of the muscle responses and for real data, an increased filter performance can be achieved by increasing the filter length. Using a filter length of up to seven stimulation periods, it is possible to reduce real muscle responses to a level comparable with the background noise. Using...... the shut-down circuit and the adaptive filter both the stimulation artifacts and the muscle responses can be effectively eliminated from the EMG signal from a stimulated muscle. It is therefore possible to extract the volitional EMG from a partly paralyzed muscle and use it for controlling the stimulation...

  17. Surface EMG to assess arm function in boys with DMD: a pilot study.

    Science.gov (United States)

    Janssen, Mariska M H P; Harlaar, Jaap; de Groot, Imelda J M

    2015-04-01

    Preserving functional abilities of the upper extremities is a major concern in boys with Duchenne Muscular Dystrophy (DMD). To assess disease progression and treatments, good knowledge on arm function in boys with DMD is essential. Therefore, feasibility and validity of the use of surface electromyography (sEMG) to assess arm function in boys with DMD was examined. Five boys with DMD and 6 age-matched controls participated in this study. Single joint movements and ADL activities were examined while recording sEMG of main shoulder and elbow muscles. All boys with DMD and controls were able to perform the non standardized movements of the measurement protocol, however one boy with DMD was not able to perform all the standardized movements. Boys with DMD used significantly more of their maximal muscle capacity for all muscles to conduct movements compared to controls. The measurement protocol was feasible to assess arm function in boys with DMD. This tool was able to discriminate between DMD patients and controls. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Abdominal strengthening using the AbVice machine as measured by surface electromyographic activation levels.

    Science.gov (United States)

    Avedisian, Lori; Kowalsky, Don S; Albro, Richard C; Goldner, Daniel; Gill, Robert C

    2005-08-01

    Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal musculature in conjunction with the abdominals, which may assist in decreasing activation of the hip flexors by allowing greater activity levels of the abdominal musculature via the theory of reflex inhibition, compared with other devices currently available on the market (AbRoller and AbRocker). The repeated-measures study included 17 women and 7 men who ranged in age from 20-23 years (mean +/- SD age, 21.3 +/- 1.5 years). Each subject underwent a single session of data collection during which they completed 10 repetitions of abdominal crunches per device. Subjects completed 4 different crunch sets (AbRocker, AbRoller, standard crunch, AbVice). Counterbalancing of the device was used to negate the effect of fatigue. Speed of repetitions was ensured via use of a metronome set at 40 b.min(-1) to permit similar contraction times and rest periods between repetitions. Rest between conditions was 3 minutes. Mean activation levels of surface electromyography (EMG) were recorded for each condition at the following locations on the right side of the body: rectus abdominis 2.5 cm superior to the umbilicus, rectus abdominis 2.5 cm inferior to the umbilicus, external oblique abdominis 1.0 cm medial to the anterior superior iliac spine, and external oblique abdominis less than 1.0 cm superior to the inguinal ligament. Mean (SD) activation was 1,165.21 mV (634.60 mV) with the AbVice, 242.92 mV (263.03 mV) with the AbRocker, 753.29 mV (514.80 mV) with the standard crunch, and 757.67 mV (542.85 mV) with the AbRoller. Broken down by sex, women had the following mean (SD) EMG values: 1,079.76 mV (705.02 mV) with the AbVice, 680.35 mV (535.35 m

  19. Evoked Electromyographically Controlled Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Hayashibe

    2016-07-01

    Full Text Available Time-variant muscle responses under electrical stimulation (ES are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications.Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES are also well known source of time-varying characteristics coming from muscle response under ES. Therefore it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favour of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

  20. Electromyographic comparison of concentric and eccentric ...

    African Journals Online (AJOL)

    The study was conducted to compare the Electromyographic (EMG) activity variation of contractions (concentric and eccentric) during three different abdominal exercises (sit-up) exercises on rectus abdominal (upper and lower rectus). The sit-up exercises were: straight leg sit-up, bent leg sit-up and crunches. The EMG ...

  1. On the behavior of surface electromyographic variables during the menstrual cycle

    International Nuclear Information System (INIS)

    Soares, Fabiano Araujo; Salomoni, Sauro Emerick; De Carvalho, Joao Luiz Azevedo; Nascimento, Francisco Assis de Oliveira; Veneziano, Wilson Henrique; Pires, Kenia Fonseca; Da Rocha, Adson Ferreira

    2011-01-01

    The goal of this work is to study the behavior of electromyographic variables during the menstrual cycle. Ten female volunteers (24.0 ± 2.8 years of age) performed fatiguing isometric contractions, and electromyographic signals were measured on the biceps brachii in four phases of the menstrual cycle. Adaptations of classical algorithms were used for the estimation of the root mean square (RMS) value, absolute rectified value (ARV), mean frequency (MNF), median frequency (MDF), and conduction velocity (CV). The CV estimator had a higher (p = 0.002) rate of decrease at the end of the follicular phase and at the end of the luteal phase. The MDF (p = 0.002) and MNF (p = 0.004) estimators had a higher rate of decrease at the beginning of the follicular phase and at the end of the luteal phase. No significant differences between phases of the menstrual cycle were detected with the ARV and RMS estimators (p > 0.05). These results suggest that the behavior of the muscles in women presents different characteristics during different phases of the menstrual cycle. In particular, women were more susceptible to fatigue at the end of the luteal phase

  2. Processing Electromyographic Signals to Recognize Words

    Science.gov (United States)

    Jorgensen, C. C.; Lee, D. D.

    2009-01-01

    A recently invented speech-recognition method applies to words that are articulated by means of the tongue and throat muscles but are otherwise not voiced or, at most, are spoken sotto voce. This method could satisfy a need for speech recognition under circumstances in which normal audible speech is difficult, poses a hazard, is disturbing to listeners, or compromises privacy. The method could also be used to augment traditional speech recognition by providing an additional source of information about articulator activity. The method can be characterized as intermediate between (1) conventional speech recognition through processing of voice sounds and (2) a method, not yet developed, of processing electroencephalographic signals to extract unspoken words directly from thoughts. This method involves computational processing of digitized electromyographic (EMG) signals from muscle innervation acquired by surface electrodes under a subject's chin near the tongue and on the side of the subject s throat near the larynx. After preprocessing, digitization, and feature extraction, EMG signals are processed by a neural-network pattern classifier, implemented in software, that performs the bulk of the recognition task as described.

  3. THE EFFECTIVENESS OF ELECTROMYOGRAPHIC BIOFEEDBACK AS PART OF A MENISCAL REPAIR REHABILITATION PROGRAMME

    Directory of Open Access Journals (Sweden)

    Mihaela Oravitan

    2013-09-01

    Full Text Available The objective of the study was to assess the effectiveness of using electromyographic biofeedback in the early stages of rehabilitation after meniscal repair. In this randomised, controlled, parallel group study, the evolution of patients with meniscal lesions treated by meniscal suture who received (study group, n = 33 or did not receive (control group, n = 31 electromyographic biofeedback as part of their early rehabilitation programme has been compared. A total of 64 patients with previous meniscal repair participated in the study. The patients received a baseline assessment (after 1 postoperative week and a follow-up (after 8 postoperative weeks consisting of surface electromyography, dynamometry of thigh muscles and the assessment of the Knee injury and Osteoarthritis Outcome Score (KOOS. The electrical potential in contraction and the speed for contraction and relaxation for all monitored muscles increased significantly in the study group (p < 0.05. The difference between groups in the assessed score was significant for sport and recreational function (p < 0.05. The strength of the thigh muscles was not significantly influenced by the introduction of electromyographic biofeedback (EMG- BFB in the rehabilitation programme. Electromyographic biofeedback helped patients to control their muscles after meniscal repair to accomplish physical activities that require better neuromuscular coordination and control. For these reasons, one may consider electromyographic biofeedback as an important component of rehabilitation after meniscal repair

  4. Electromyographic analysis of muscle activation during sit-and-reach flexibility tests.

    Science.gov (United States)

    Mookerjee, Swapan; McMahon, Matthew J

    2014-12-01

    The sit-and-reach test (SRT) has been included in standard fitness test batteries for decades, but empirical evidence of actual muscle activity has been lacking. Furthermore, the positioning of the ankle joint during the execution of this test has received relatively scant attention. Therefore, the purpose of this investigation was to compare surface electromyographic (sEMG) activity of selected lower extremity and back musculature and examine the impact of ankle positioning during the standard SRT and the modified sit-and-reach test (MSRT). Seven male and 7 female subjects performed 3 trials of the SRT and MSRT, each in a dorsiflexed and plantar flexed ankle position. During all trials, muscle activity (sEMG) was measured from the right semimembranous (SM), erector spinae (ES), and gastrocnemius (G). Mean sEMG data from each muscle (SM, ES, and G) were normalized by being expressed as a percent contribution to the total electrical activity (100%). Surface electromyographic activity data were also used to determine muscle activation ratios (e.g., SM to ES). Results revealed significantly higher flexibility scores during the plantar flexion condition for both test modalities. The SM exhibited the greatest percent contribution to total sEMG activity within all testing conditions. The SM to G and SM to ES muscle activation ratios were significantly greater than their inverse counterparts within all 4 testing conditions. Based on the 2 sEMG analysis techniques, the SM seemed to exhibit the greatest muscle activity. This investigation provides direct evidence of sEMG muscle activity during the SRT and MSRT, further confirming these tests to be a valid measure of hamstring flexibility.

  5. Does breathing type influence electromyographic activity of obligatory and accessory respiratory muscles?

    Science.gov (United States)

    Gutiérrez, M F; Valenzuela, S; Miralles, R; Portus, C; Santander, H; Fuentes, A D; Celhay, I

    2014-11-01

    Craniomandibular electromyographic (EMG) studies frequently include several parameters, e.g. resting, chewing and tooth-clenching. EMG activity during these parameters has been recorded in the elevator muscles, but little is known about the respiratory muscles. The aim of this study was to compare EMG activity in obligatory and accessory respiratory muscles between subjects with different breathing types. Forty male subjects were classified according to their breathing type into two groups of 20 each: costo-diaphragmatic breathing type and upper costal breathing type. Bipolar surface electrodes were placed on the sternocleidomastoid, diaphragm, external intercostal and latissimus dorsi muscles. EMG activity was recorded during the following tasks: (i) normal quiet breathing, (ii) maximal voluntary clenching in intercuspal position, (iii) natural rate chewing until swallowing threshold, (iv) short-time chewing. Diaphragm EMG activity was significantly higher in the upper costal breathing type than in the costo-diaphragmatic breathing type in all tasks (P breathing type than in the costo-diaphragmatic breathing type in tasks 3 and 4 (P breathing types in the tasks studied (P > 0·05). The significantly higher EMG activity observed in subjects with upper costal breathing than in the costo-diaphragmatic breathing type suggests that there could be differences in motor unit recruitment strategies depending on the breathing type. This may be an expression of the adaptive capability of muscle chains in subjects who clinically have a different thoraco-abdominal expansion during inspiration at rest. © 2014 John Wiley & Sons Ltd.

  6. A Wearable System for Recognizing American Sign Language in Real-Time Using IMU and Surface EMG Sensors.

    Science.gov (United States)

    Wu, Jian; Sun, Lu; Jafari, Roozbeh

    2016-09-01

    A sign language recognition system translates signs performed by deaf individuals into text/speech in real time. Inertial measurement unit and surface electromyography (sEMG) are both useful modalities to detect hand/arm gestures. They are able to capture signs and the fusion of these two complementary sensor modalities will enhance system performance. In this paper, a wearable system for recognizing American Sign Language (ASL) in real time is proposed, fusing information from an inertial sensor and sEMG sensors. An information gain-based feature selection scheme is used to select the best subset of features from a broad range of well-established features. Four popular classification algorithms are evaluated for 80 commonly used ASL signs on four subjects. The experimental results show 96.16% and 85.24% average accuracies for intra-subject and intra-subject cross session evaluation, respectively, with the selected feature subset and a support vector machine classifier. The significance of adding sEMG for ASL recognition is explored and the best channel of sEMG is highlighted.

  7. EMG-force relationship during static contraction: Effects on sensor placement locations on biceps brachii muscle.

    Science.gov (United States)

    Ahamed, Nizam Uddin; Sundaraj, Kenneth; Alqahtani, Mahdi; Altwijri, Omar; Ali, Md Asraf; Islam, Md Anamul

    2014-10-15

    The relationship between surface electromyography (EMG) and force have been the subject of ongoing investigations and remain a subject of controversy. Even under static conditions, the relationships at different sensor placement locations in the biceps brachii (BB) muscle are complex. The aim of this study was to compare the activity and relationship between surface EMG and static force from the BB muscle in terms of three sensor placement locations. Twenty-one right hand dominant male subjects (age 25.3 ± 1.2 years) participated in the study. Surface EMG signals were detected from the subject's right BB muscle. The muscle activation during force was determined as the root mean square (RMS) electromyographic signal normalized to the peak RMS EMG signal of isometric contraction for 10 s. The statistical analysis included linear regression to examine the relationship between EMG amplitude and force of contraction [40-100% of maximal voluntary contraction (MVC)], repeated measures ANOVA to assess differences among the sensor placement locations, and coefficient of variation (CoV) for muscle activity variation. The results demonstrated that when the sensor was placed on the muscle belly, the linear slope coefficient was significantly greater for EMG versus force testing (r^{2} = 0.61, P > 0.05) than when placed on the lower part (r^{2}=0.31, Pr^{2}=0.29, P > 0.05). In addition, the EMG signal activity on the muscle belly had less variability than the upper and lower parts (8.55% vs. 15.12% and 12.86%, respectively). These findings indicate the importance of applying the surface EMG sensor at the appropriate locations that follow muscle fiber orientation of the BB muscle during static contraction. As a result, EMG signals of three different placements may help to understand the difference in the amplitude of the signals due to placement.

  8. Identification of Onset Of Fatigue in Biceps Brachii Muscles Using Surface EMG and Multifractal DMA Alogrithm.

    Science.gov (United States)

    Marri, Kiran; Swaminathan, Ramakrishnan

    2015-01-01

    Prolonged and repeated fatigue conditions can cause muscle damage and adversely impact coordination in dynamic contractions. Hence it is important to determine the onset of muscle fatigue (OMF) in clinical rehabilitation and sports medicine. The aim of this study is to propose a method for analyzing surface electromyography (sEMG) signals and identify OMF using multifractal detrending moving average algorithm (MFDMA). Signals are recorded from biceps brachii muscles of twenty two healthy volunteers while performing standard curl exercise. The first instance of muscle discomfort during curl exercise is considered as experimental OMF. Signals are pre-processed and divided into 1-second epoch for MFDMA analysis. Degree of multifractality (DOM) feature is calculated from multifractal spectrum. Further, the variance of DOM is computed and OMF is calculated from instances of high peaks. The analysis is carried out by dividing the entire duration into six equal zones for time axis normalization. High peaks are observed in zones where subjects reported muscle discomfort. First muscle discomfort occurred in third and forth zones for majority of subjects. The calculated and experimental muscle discomfort zone closely matched in 72% of subjects indicating that multifractal technique may be a good method for detecting onset of fatigue. The experimental data may have an element of subjectivity in identifying muscle discomfort. This work can also be useful to analyze progressive changes in muscle dynamics in neuromuscular condition and co-contraction activity.

  9. Electromyographic amplitude variability of chewing cycles in deaf individuals.

    Science.gov (United States)

    de Oliveira, A Siriani; Vitti, M; Chaves, T C; Bevilaqua-Grossi, D; Zuccolotto, M C C; Regalo, S C H

    2006-09-01

    This study had the goal of determining if the amplitude of the surface electromyograph signals changes in terms of time of analysis and subjects, deaf or normal listeners, when estimated in a 250 ms of length window, visually determined, considering the most stable signal period from the center of the chewing cycle. In order to do this, groups with control subjects, listeners and deaf individuals, who made use of the Brazilian sign language (LIBRAS), were studied. All participants performed continuous 5 s of chewing for the electromyographic recording of the temporalis and masseter muscles. The normalized RMS values of three chewing cycles were compared between and among groups. The results from the Kruskall-Wallis test did not show any statistically significant differences (p > 0.05) between the normalized RMS values obtained in the three individual chewing cycles, for each of the two completed and evaluated cycles, in both groups studied. The Mann-Whitney test showed that the mean normalized RMS values obtained in the first chewing cycle were higher for the control group when compared to the mean amplitude values of the first chewing cycle of the group of deaf volunteers. It can be concluded that, in these experimental conditions, the RMS values obtained from the select windows of 250 ms length duration, in relatively stable periods of the electromyographic signal of chewing cycles did not suffer any changes in terms of EMG register duration, in both studied groups, but does give evidence of the differences among the groups.

  10. Spatial localization of electromyographic amplitude distributions associated to the activation of dorsal forearm muscles

    Directory of Open Access Journals (Sweden)

    Alessio eGallina

    2013-12-01

    Full Text Available In this study we investigated whether the spatial distribution of surface electromyographic (EMG amplitude can be used to describe the activation of muscle portions with different biomechanical actions. Ten healthy subjects performed isometric contractions aimed to selectively activate a number of forearm muscles or muscle subportions. Monopolar electromyographic signals were collected with an electrode grid of 128 electrodes placed on the proximal, dorsal portion of the forearm. The monopolar EMG amplitude (root mean square value distribution was calculated for each contraction, and high-amplitude channels were identified through an automatic procedure; the position of the EMG source was estimated with the barycenter of these channels. Each of the contractions tested was associated to a specific EMG amplitude distribution, whose location in space was consistent with the expected anatomical position of the main agonist muscle (or subportion. The position of each source was significantly different from the others in at least one direction (ANOVA; transversally to the forearm: P < 0.01, F = 125.92; longitudinally: P < 0.01, F = 35.83. With such an approach, we could distinguish the spatial position of EMG distributions related to the activation of contiguous muscles (e.g.: extensor carpi ulnaris and extensor digitorum communis, different heads of the same muscle (i.e.: extensor carpi radialis brevis and longus and different functional compartments (i.e.: extensor digitorum communis, middle and ring fingers. These findings are discussed in terms of how forces along a given direction can be produced by recruiting population of motor units clustered not only in specific muscles, but also in muscle sub-portions. In addition, this study supports the use of high-density EMG systems to characterize the activation of muscle subportions with different biomechanical actions.

  11. Analysis of High-Density Surface EMG and Finger Pressure in the Left Forearm of Violin Players: A Feasibility Study.

    Science.gov (United States)

    Cattarello, Paolo; Merletti, Roberto; Petracca, Francesco

    2017-09-01

    Wrist and finger flexor muscles of the left hand were evaluated using high-density surface EMG (HDsEMG) in 17 violin players. Pressure sensors also were mounted below the second string of the violin to evaluate, simultaneously, finger pressure. Electrode grid size was 110x70 mm (12x8 electrodes with interelectrode distance=10 mm and Ø=3 mm). The study objective was to observe the activation patterns of these muscles while the violinists sequentially played four notes--SI (B), DO# (C#), RE (D), MI (E)--at 2 bows/s (one bow up in 0.5 s and one down in 0.5 s) and 4 bows/s on the second string, while producing a constant (CONST) or ramp (RAMP) sound volume. HDsEMG images obtained while playing the notes were compared with those obtained during isometric radial or ulnar flexion of the wrist or fingers. Two image descriptors provided information on image differences. Results showed that the technique was reliable and provided reliable signals, and that recognizably different sEMG images could be associated with the four notes tested, despite the variability within and between subjects playing the same note. sEMG activity of the left hand muscles and pressure on the string in the RAMP task were strongly affected in some individuals by the sound volume (controlled by the right hand) and much less in other individuals. These findings question whether there is an individual or generally optimal way of pressing violin strings with the left hand. The answer to this question might substantially modify the teaching of string instruments.

  12. Random Forest-Based Recognition of Isolated Sign Language Subwords Using Data from Accelerometers and Surface Electromyographic Sensors.

    Science.gov (United States)

    Su, Ruiliang; Chen, Xiang; Cao, Shuai; Zhang, Xu

    2016-01-14

    Sign language recognition (SLR) has been widely used for communication amongst the hearing-impaired and non-verbal community. This paper proposes an accurate and robust SLR framework using an improved decision tree as the base classifier of random forests. This framework was used to recognize Chinese sign language subwords using recordings from a pair of portable devices worn on both arms consisting of accelerometers (ACC) and surface electromyography (sEMG) sensors. The experimental results demonstrated the validity of the proposed random forest-based method for recognition of Chinese sign language (CSL) subwords. With the proposed method, 98.25% average accuracy was obtained for the classification of a list of 121 frequently used CSL subwords. Moreover, the random forests method demonstrated a superior performance in resisting the impact of bad training samples. When the proportion of bad samples in the training set reached 50%, the recognition error rate of the random forest-based method was only 10.67%, while that of a single decision tree adopted in our previous work was almost 27.5%. Our study offers a practical way of realizing a robust and wearable EMG-ACC-based SLR systems.

  13. High-density surface EMG maps from upper-arm and forearm muscles

    Directory of Open Access Journals (Sweden)

    Rojas-Martínez Monica

    2012-12-01

    Full Text Available Abstract Background sEMG signal has been widely used in different applications in kinesiology and rehabilitation as well as in the control of human-machine interfaces. In general, the signals are recorded with bipolar electrodes located in different muscles. However, such configuration may disregard some aspects of the spatial distribution of the potentials like location of innervation zones and the manifestation of inhomogineties in the control of the muscular fibers. On the other hand, the spatial distribution of motor unit action potentials has recently been assessed with activation maps obtained from High Density EMG signals (HD-EMG, these lasts recorded with arrays of closely spaced electrodes. The main objective of this work is to analyze patterns in the activation maps, associating them with four movement directions at the elbow joint and with different strengths of those tasks. Although the activation pattern can be assessed with bipolar electrodes, HD-EMG maps could enable the extraction of features that depend on the spatial distribution of the potentials and on the load-sharing between muscles, in order to have a better differentiation between tasks and effort levels. Methods An experimental protocol consisting of isometric contractions at three levels of effort during flexion, extension, supination and pronation at the elbow joint was designed and HD-EMG signals were recorded with 2D electrode arrays on different upper-limb muscles. Techniques for the identification and interpolation of artifacts are explained, as well as a method for the segmentation of the activation areas. In addition, variables related to the intensity and spatial distribution of the maps were obtained, as well as variables associated to signal power of traditional single bipolar recordings. Finally, statistical tests were applied in order to assess differences between information extracted from single bipolar signals or from HD-EMG maps and to analyze

  14. Assessment of work-related muscle strain by using surface EMG during test contractions interposed between work periods of simulateted mushroom picking

    DEFF Research Database (Denmark)

    Ohashi, Jun-Ya; Blangsted, Anne Katrine; Nielsen, Pernille Kofoed

    2010-01-01

    Surface electromyograms(EMG) during test contractions (TCs) were studied to assess the muscle strain in simulated mushroom picking. Additionally, the duration of the TC for the effective assessment was investigated. Nine female subjects performed standardized shoulder abduction and a stooped...... minutes in the rest periods. EMGs were recorded from the trapezius, infraspinatus, deltoid, and erector spinae muscles. The amplitude of EMG (AEMG) and mean power frequency (MPF) of EMG were calculated. Each TC was divided equally into three parts. Ratings of perceived exertion (RPE) in the neck, shoulder...... during the TCs. AEMG and MPF fluctuated before W1 although the changes of RPE were small. Averaging several TCs was recommended to get stable results from TCs. EMG changes and appropriate TC conditions were discussed in relation to the adaptation in fatiguing contractions....

  15. Arm Orthosis/Prosthesis Movement Control Based on Surface EMG Signal Extraction.

    Science.gov (United States)

    Suberbiola, Aaron; Zulueta, Ekaitz; Lopez-Guede, Jose Manuel; Etxeberria-Agiriano, Ismael; Graña, Manuel

    2015-05-01

    This paper shows experimental results on electromyography (EMG)-based system control applied to motorized orthoses. Biceps and triceps EMG signals are captured through two biometrical sensors, which are then filtered and processed by an acquisition system. Finally an output/control signal is produced and sent to the actuators, which will then perform the actual movement, using algorithms based on autoregressive (AR) models and neural networks, among others. The research goal is to predict the desired movement of the lower arm through the analysis of EMG signals, so that the movement can be reproduced by an arm orthosis, powered by two linear actuators. In this experiment, best accuracy has achieved values up to 91%, using a fourth-order AR-model and 100ms block length.

  16. The potential use of spectral electromyographic fatigue as a screening and outcome monitoring tool of sarcopenic back muscle alterations.

    Science.gov (United States)

    Kienbacher, Thomas; Habenicht, Richard; Starek, Christian; Mair, Patrick; Wolf, Markus; Paul, Birgit; Riegler, Sara; Kollmitzer, Josef; Ebenbichler, Gerold

    2014-07-02

    To examine whether or not median frequency surface electromyographic (MF-EMG) back muscle fatigue monitoring would be able to identify alterations in back muscle function in elderly muscles, if a protocol was used that allowed optimum standardization of the processes underlying electromyographic fatigue, and whether these tests were reliable from day to day. A total of 42 older (21 females; 67 (±10.5) years old) and 44 younger persons (19 females; 33 (±10) years) performed maximum isometric back extensions which were followed by one 30 s lasting 80% submaximum extension. Participants were seated on a dynamometer with their trunks 30° anteflexed, and they repeated all tests after 1-2 days and 6 weeks. SEMG was recorded bilaterally from the L1 (iliocostalis lumborum), L2 (longissimus), and L5 (multifidus) recording sites. Outcome variables included maximum back extension torque, initial MF-EMG (IMF-EMG), MF-EMG slope declines, and individual MF-EMG muscular imbalance scores. Two-factorial ANOVAs served to examine the age and gender-specific effects, and models from Generalizability Theory (G-Theory) were used for assessing retest-reliability. Maximum back extension moment was non-significantly smaller in elders. IMF-EMG was overall higher in elders, with significant differences at the L5 recordings sites. In the elderly, MF-EMG fatigue declines were significantly smaller in L5, in the recording with the most negative slope, or if the slope of all electrodes was considered. Retest reliability was unanimous in young and older persons. ICC-type measurements from G-Theory of both the IMF and the fatigue slopes ranged from 0.7 to 0.85. Absolute SEM values were found clinically acceptable for the IMF-EMG, but relatively high for the fatigue slope declines. The MF-EMG fatigue method is able to elucidate alterations of aging back muscles. This method, thus, might be suggested as a potential biomarker to objectively identify persons at risk for sarcopenia. Considering

  17. Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss

    Directory of Open Access Journals (Sweden)

    Truong Quang Dang Khoa

    2012-08-01

    Full Text Available Abstract Background This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. Methods In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG and Higuchi fractal dimension (HFD were used to analyze the EMG signals. Results The results showed that (1 Imbalance in the jaw causes loss of arm strength contra-laterally; (2 The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased. In addition, the tendency of Higuchi fractal dimension decreased for all muscles. Conclusions This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength.

  18. Comparative study of PCA in classification of multichannel EMG signals.

    Science.gov (United States)

    Geethanjali, P

    2015-06-01

    Electromyographic (EMG) signals are abundantly used in the field of rehabilitation engineering in controlling the prosthetic device and significantly essential to find fast and accurate EMG pattern recognition system, to avoid intrusive delay. The main objective of this paper is to study the influence of Principal component analysis (PCA), a transformation technique, in pattern recognition of six hand movements using four channel surface EMG signals from ten healthy subjects. For this reason, time domain (TD) statistical as well as auto regression (AR) coefficients are extracted from the four channel EMG signals. The extracted statistical features as well as AR coefficients are transformed using PCA to 25, 50 and 75 % of corresponding original feature vector space. The classification accuracy of PCA transformed and non-PCA transformed TD statistical features as well as AR coefficients are studied with simple logistic regression (SLR), decision tree (DT) with J48 algorithm, logistic model tree (LMT), k nearest neighbor (kNN) and neural network (NN) classifiers in the identification of six different movements. The Kruskal-Wallis (KW) statistical test shows that there is a significant reduction (P PCA transformed features compared to non-PCA transformed features. SLR with non-PCA transformed time domain (TD) statistical features performs better in accuracy and computational power compared to other features considered in this study. In addition, the motion control of three drives for six movements of the hand is implemented with SLR using TD statistical features in off-line with TMSLF2407 digital signal controller (DSC).

  19. Reliability of surface EMG as an assessment tool for trunk activity and potential to determine neurorecovery in SCI.

    Science.gov (United States)

    Mitchell, M D; Yarossi, M B; Pierce, D N; Garbarini, E L; Forrest, G F

    2015-05-01

    Reliability and validity study. This study investigates the responsiveness and reliability of the brain motor control assessment (BMCA) as a standardized neurophysiological assessment tool to: (i) characterize trunk neural activity in neurologically-intact controls; (ii) measure and quantify neurorecovery of trunk after spinal cord injury (SCI). Kessler Foundation Research Center, West Orange, NJ. A standardized BMCA protocol was performed to measure surface electromyography (sEMG) recordings for seven bilateral trunk muscles on 15 able-bodied controls during six maneuvers (inhalation, exhalation, neck flexion, jendrassik, unilateral grip). Additionally, sEMG recordings were analyzed for one chronic SCI individual before electrical stimulation (ES), after ES of the lower extremities while supine, and after active stand training using body-weight support with bilateral ES. sEMG recordings were collected on bilateral erector spinae, internal and external obliques, upper and middle trapezius, biceps and triceps. For each maneuver a voluntary response index was calculated: incorporating the magnitude of sEMG signal and a similarity index (SI), which quantifies the distribution of activity across all muscles. Among all maneuvers, the SI presented reproducible assessment of trunk-motor function within (ICC: 0.860-0.997) and among (P⩾0.22) able-bodied individuals. In addition, potential changes were measured in a chronic SCI individual after undergoing two intensive ES protocols. The BMCA provides reproducible characterization of trunk activity in able-bodied individuals, lending credence for its use in neurophysiological assessment of motor control. Additionally, the BMCA as an assessment tool to measure neurorecovery in an individual with chronic SCI after intense ES interventions was demonstrated.

  20. Use of the discriminant Fourier-derived cepstrum with feature-level post-processing for surface electromyographic signal classification

    International Nuclear Information System (INIS)

    Chen, Xinpu; Zhu, Xiangyang; Zhang, Dingguo

    2009-01-01

    Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum takes advantage of the Fourier magnitude or sub-band power energy of signals directly and provides flexible use of spectral information changing with different motions. Appropriate cepstral coefficients are selected by a proposed separability criterion to construct DFC features. For the post-processing, FLPP which combines features from several analysis windows is used to improve the feature performance further. In this work, two classifiers (a linear discriminant classifier and quadratic discriminant classifier) without hyper-parameter optimization are employed to simplify the training procedure and avoid the possible bias of feature evaluation. Experimental results of the 11-motion problem show that the proposed DFC feature outperforms traditional features such as time-domain statistics and autoregressive-derived cepstrum in terms of the classification accuracy, and it is a promising method for the multi-functionality and high-accuracy control of myoelectric prostheses

  1. Spatial localization of electromyographic amplitude distributions associated to the activation of dorsal forearm muscles

    Science.gov (United States)

    Gallina, Alessio; Botter, Alberto

    2013-01-01

    In this study we investigated whether the spatial distribution of surface electromyographic (EMG) amplitude can be used to describe the activation of muscle portions with different biomechanical actions. Ten healthy subjects performed isometric contractions aimed to selectively activate a number of forearm muscles or muscle subportions. Monopolar electromyographic signals were collected with an electrode grid of 128 electrodes placed on the proximal, dorsal portion of the forearm. The monopolar EMG amplitude [root mean square (RMS) value] distribution was calculated for each contraction, and high-amplitude channels were identified through an automatic procedure; the position of the EMG source was estimated with the barycenter of these channels. Each of the contractions tested was associated to a specific EMG amplitude distribution, whose location in space was consistent with the expected anatomical position of the main agonist muscle (or subportion). The position of each source was significantly different from the others in at least one direction (ANOVA; transversally to the forearm: P extensor carpi ulnaris (ECU) and extensor digitorum communis (EDC)], different heads of the same muscle (i.e., extensor carpi radialis (ECR) brevis and longus) and different functional compartments (i.e., EDC, middle, and ring fingers). These findings are discussed in terms of how forces along a given direction can be produced by recruiting population of motor units clustered not only in specific muscles, but also in muscle sub-portions. In addition, this study supports the use of high-density EMG systems to characterize the activation of muscle subportions with different biomechanical actions. PMID:24379788

  2. Influence of changing occlusal support on jaw-closing muscle electromyographic activity in healthy men and women.

    Science.gov (United States)

    Wang, Mei-Qing; He, Jian-Jun; Wang, Kelun; Svensson, Peter

    2009-01-01

    To test whether changes in occlusal support differentially modulate masseter and anterior temporalis muscle electromyographic (EMG) activity during controlled maximal voluntary clenching. Forty-seven healthy subjects (32 M and 15 F, 22.9+/-1.3 years) were recruited. Cotton-rolls were used to modify the occlusal contact relations and were positioned on the right, left, or both sides, and either in the molar or premolar regions, i.e. six different occlusal combinations. Surface EMG activity was recorded bilaterally from the masseter and anterior temporalis area and normalized with respect to maximal voluntary clenching in the intercuspal position. Analysis of variance and the paired t-test were used to test the data. Normalized EMG activity was influenced by changes in cotton-roll modified occlusal support, and there were differences between muscles (pocclusal support was moved from the molar to the premolar region. When occlusal support was moved from bilateral to unilateral contacts, EMG activity in the balancing-side anterior temporalis muscle and in bilateral masseter muscles decreased. Unilateral clenching on the molars, but not on the premolars, was associated with lower EMG activity in the balancing-side masseter and always associated with lower EMG activity in the balancing-side anterior temporalis compared to the working side (pocclusal support, which may have implications for stability of the mandible during intense clenching.

  3. Gait in adolescent idiopathic scoliosis: kinematics and electromyographic analysis.

    Science.gov (United States)

    Mahaudens, P; Banse, X; Mousny, M; Detrembleur, C

    2009-04-01

    Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. Consequently, AIS can modify human locomotion. Very few studies have investigated a simple activity like walking in a cohort of well-defined untreated patients with scoliosis. The first goal of this study is to evaluate the effects of scoliosis and scoliosis severity on kinematic and electromyographic (EMG) gait variables compared to an able-bodied population. The second goal is to look for any asymmetry in these parameters during walking. Thirteen healthy girls and 41 females with untreated AIS, with left thoracolumbar or lumbar primary structural curves were assessed. AIS patients were divided into three clinical subgroups (group 1 40 degrees). Gait analysis included synchronous bilateral kinematic and EMG measurements. The subjects walked on a treadmill at 4 km/h (comfortable speed). The tridimensional (3D) shoulder, pelvis, and lower limb motions were measured using 22 reflective markers tracked by four infrared cameras. The EMG timing activity was measured using bipolar surface electrodes on quadratus lumborum, erector spinae, gluteus medius, rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius muscles. Statistical comparisons (ANOVA) were performed across groups and sides for kinematic and EMG parameters. The step length was reduced in AIS compared to normal subjects (7% less). Frontal shoulder, pelvis, and hip motion and transversal hip motion were reduced in scoliosis patients (respectively, 21, 27, 28, and 22% less). The EMG recording during walking showed that the quadratus lumborum, erector spinae, gluteus medius, and semitendinosus muscles contracted during a longer part of the stride in scoliotic patients (46% of the stride) compared with normal subjects (35% of the stride). There was no significant difference between scoliosis groups 1, 2, and 3 for any of the kinematic and EMG parameters, meaning

  4. Hybrid soft computing systems for electromyographic signals analysis: a review

    Science.gov (United States)

    2014-01-01

    Electromyographic (EMG) is a bio-signal collected on human skeletal muscle. Analysis of EMG signals has been widely used to detect human movement intent, control various human-machine interfaces, diagnose neuromuscular diseases, and model neuromusculoskeletal system. With the advances of artificial intelligence and soft computing, many sophisticated techniques have been proposed for such purpose. Hybrid soft computing system (HSCS), the integration of these different techniques, aims to further improve the effectiveness, efficiency, and accuracy of EMG analysis. This paper reviews and compares key combinations of neural network, support vector machine, fuzzy logic, evolutionary computing, and swarm intelligence for EMG analysis. Our suggestions on the possible future development of HSCS in EMG analysis are also given in terms of basic soft computing techniques, further combination of these techniques, and their other applications in EMG analysis. PMID:24490979

  5. Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises.

    Science.gov (United States)

    Ebenbichler, Gerold R; Unterlerchner, Lena; Habenicht, Richard; Bonato, Paolo; Kollmitzer, Josef; Mair, Patrick; Riegler, Sara; Kienbacher, Thomas

    2017-01-01

    Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG) data. Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's), an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG) and the instantaneous median frequency (IMDF-SEMG) estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise. Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise. Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

  6. Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises

    Directory of Open Access Journals (Sweden)

    Gerold R. Ebenbichler

    2017-05-01

    Full Text Available Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG data.Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's, an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG and the instantaneous median frequency (IMDF-SEMG estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise.Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise.Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

  7. Motor Function Evaluation of Hemiplegic Upper-Extremities Using Data Fusion from Wearable Inertial and Surface EMG Sensors

    Directory of Open Access Journals (Sweden)

    Yanran Li

    2017-03-01

    Full Text Available Quantitative evaluation of motor function is of great demand for monitoring clinical outcome of applied interventions and further guiding the establishment of therapeutic protocol. This study proposes a novel framework for evaluating upper limb motor function based on data fusion from inertial measurement units (IMUs and surface electromyography (EMG sensors. With wearable sensors worn on the tested upper limbs, subjects were asked to perform eleven straightforward, specifically designed canonical upper-limb functional tasks. A series of machine learning algorithms were applied to the recorded motion data to produce evaluation indicators, which is able to reflect the level of upper-limb motor function abnormality. Sixteen healthy subjects and eighteen stroke subjects with substantial hemiparesis were recruited in the experiment. The combined IMU and EMG data yielded superior performance over the IMU data alone and the EMG data alone, in terms of decreased normal data variation rate (NDVR and improved determination coefficient (DC from a regression analysis between the derived indicator and routine clinical assessment score. Three common unsupervised learning algorithms achieved comparable performance with NDVR around 10% and strong DC around 0.85. By contrast, the use of a supervised algorithm was able to dramatically decrease the NDVR to 6.55%. With the proposed framework, all the produced indicators demonstrated high agreement with the routine clinical assessment scale, indicating their capability of assessing upper-limb motor functions. This study offers a feasible solution to motor function assessment in an objective and quantitative manner, especially suitable for home and community use.

  8. S-EMG signal compression based on domain transformation and spectral shape dynamic bit allocation.

    Science.gov (United States)

    Trabuco, Marcel Henrique; Costa, Marcus Vinícius Chaffim; Nascimento, Francisco Assis de Oliveira

    2014-02-27

    Surface electromyographic (S-EMG) signal processing has been emerging in the past few years due to its non-invasive assessment of muscle function and structure and because of the fast growing rate of digital technology which brings about new solutions and applications. Factors such as sampling rate, quantization word length, number of channels and experiment duration can lead to a potentially large volume of data. Efficient transmission and/or storage of S-EMG signals are actually a research issue. That is the aim of this work. This paper presents an algorithm for the data compression of surface electromyographic (S-EMG) signals recorded during isometric contractions protocol and during dynamic experimental protocols such as the cycling activity. The proposed algorithm is based on discrete wavelet transform to proceed spectral decomposition and de-correlation, on a dynamic bit allocation procedure to code the wavelets transformed coefficients, and on an entropy coding to minimize the remaining redundancy and to pack all data. The bit allocation scheme is based on mathematical decreasing spectral shape models, which indicates a shorter digital word length to code high frequency wavelets transformed coefficients. Four bit allocation spectral shape methods were implemented and compared: decreasing exponential spectral shape, decreasing linear spectral shape, decreasing square-root spectral shape and rotated hyperbolic tangent spectral shape. The proposed method is demonstrated and evaluated for an isometric protocol and for a dynamic protocol using a real S-EMG signal data bank. Objective performance evaluations metrics are presented. In addition, comparisons with other encoders proposed in scientific literature are shown. The decreasing bit allocation shape applied to the quantized wavelet coefficients combined with arithmetic coding results is an efficient procedure. The performance comparisons of the proposed S-EMG data compression algorithm with the established

  9. Multiscale feature based analysis of surface EMG signals under fatigue and non-fatigue conditions.

    Science.gov (United States)

    Navaneethakrishna, M; Ramakrishnan, S

    2014-01-01

    In this work, an attempt has been made to differentiate sEMG signals under muscle fatigue and non-fatigue conditions using multiscale features. Signals are recorded from biceps brachii muscle of 50 normal adults during repetitive dynamic contractions. After prescribed preprocessing, each signal is divided into six segments out of which first and last segments are considered in this analysis. Multiscale RMS (MSRMS) and Multiscale Permutation Entropy (MSPE) are computed for each subject in the time scales ranging from 1 to 50. The median values of the MSRMS and MSPE are calculated for further analysis. The results show an increase in amplitude for sEMG signals under fatigue condition. MSRMS values are found to be significantly higher in fatigue. An approximately constant difference in MSRMS value between fatigue and non-fatigue condition is observed over the entire time scale with a negative slope. Further, the median of MSRMS values for each subject is able to distinguish fatigue and non-fatigue conditions. Similar analysis on MSPE showed significant difference between fatigue and non-fatigue cases and lower values of MSPE is observed in fatigue. It is also observed that the median value of MSRMS and MSPE are able to distinguish these conditions. t-test for MSRMS, MSPE and their median value show high statistical significance. It appears that this method of analysis can be used for clinical evaluation of muscles.

  10. The effect of handedness on electromyographic activity of human shoulder muscles during movement

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

    2006-01-01

    The aim of the study was to investigate whether there was a difference in the electromyographic (EMG) activity of human shoulder muscles between the dominant and nondominant side during movement and to explore whether a possible side-difference depends on the specific task. We compared the EMG ac...

  11. Botulinum toxin in cervical dystonia: low dosage with electromyographic guidance

    NARCIS (Netherlands)

    Brans, J. W.; de Boer, I. P.; Aramideh, M.; Ongerboer de Visser, B. W.; Speelman, J. D.

    1995-01-01

    Sixty patients with idiopathic cervical dystonia were treated a total of 240 times with botulinum toxin type A (BTA). Selected muscles were injected with BTA under electromyographic (EMG) guidance. The clinical effect was measured on the Tsui scale and a 10-point anchored visual analogue scale. A

  12. Electromyographic and kinetic analysis of two abdominal muscle performance tests.

    Science.gov (United States)

    Haladay, Douglas E; Denegar, Craig R; Miller, Sayers J; Challis, John

    2015-01-01

    In order to accurately assess the abdominal muscles, clinicians need valid clinical measures. The double leg lowering test (DLLT) and lower abdominal muscle progression (LAMP) are two common tests of abdominal muscle performance. The purposes of this study were to determine the relation between surface electromyographic (EMG) activity during the DLLT and LAMP levels; hip joint resultant moments and DLLT and LAMP levels; and the two measures of DLLT and LAMP. Ten healthy participants were tested under both conditions. Surface EMG activity of the abdominal muscles was obtained, while pelvic movement was detected simultaneously. A moderate to strong association was found between rectus abdominus muscle activity and a moderate association with the external obliques with both test levels. For the internal oblique/transversus abdominus, a moderate and weak association was found with the DLLT and LAMP, respectively. A very strong association existed between the hip resultant joint moments (RJM) and the DLLT, while there was a weak correlation between hip RJM and the LAMP. No significant correlation was found between the DLLT and LAMP grades. This finding suggests that these tests may measure different qualities of muscle performance and provides preliminary support for their use. Further evaluation of these assessments with clinical populations is necessary.

  13. Effects of sampling rate on automated fatigue recognition in surface EMG signals

    Directory of Open Access Journals (Sweden)

    Kahl Lorenz

    2015-09-01

    Full Text Available This study investigated the effects different sampling rates may produce on the quality of muscle fatigue detection algorithms. sEMG signals were obtained from isometric contractions of the arm. Subsampled signals resulting in technically relevant sampling rates were computationally deduced from the original recordings. The spectral based fatigue recognition methods mean and median frequency as well as spectral moment ratio were included in this investigation, as well as the sample and the fuzzy approximate entropy. The resulting fatigue indices were evaluated with respect to noise and separability of different load levels. We concluded that the spectral moment ratio provides the best results in fatigue detection over a wide range of sampling rates.

  14. Functional Neuromuscular Stimulation Controlled by Surface Electromyographic Signals Produced by the Volitional Activation of the Same Muscle:

    DEFF Research Database (Denmark)

    Sennels, Søren; Fin, Biering-Sørensen; Andersen, Ole Trier

    1997-01-01

    Using the voluntary EMG as a control signal for the stimulation of the same muscle necessitates elimination of stimulus artifacts and the muscle response caused by the stimulation. The stimulus artifacts are easily eliminated by shutting down the amplifier during stimulation. The muscle response ...... comparable with the background noise. It is thus possible to extract the voluntary EMG from a partly paralysed muscle and use it for controlling the stimulation of the same muscle.......Using the voluntary EMG as a control signal for the stimulation of the same muscle necessitates elimination of stimulus artifacts and the muscle response caused by the stimulation. The stimulus artifacts are easily eliminated by shutting down the amplifier during stimulation. The muscle response...

  15. Differences in the electromyographic activity of the hamstring muscles during maximal eccentric knee flexion.

    Science.gov (United States)

    Higashihara, Ayako; Ono, Takashi; Kubota, Jun; Fukubayashi, Toru

    2010-01-01

    This study investigated the effects of the knee joint angle and angular velocity on hamstring muscles' activation patterns during maximum eccentric knee flexion contractions. Ten healthy young males (23.4 +/- 1.3 years) performed eccentric knee flexion at constant velocities of 10, 60, 180, and 300 deg/s in random order. The eccentric knee flexion torque and the surface electromyographic (EMG) activity of the biceps femoris (BF), semitendinosus (ST), and semimembranosus (SM) muscles were measured. The results of torque during 10 deg/s were lower than the faster velocities. No significant change was found in eccentric torque output and the EMG amplitude with change in the faster test velocities, although those values showed a decreasing tendency as the knee approached extension. Furthermore, the EMG amplitude of the BF decreased significantly as the knee approached extension, although the EMG activity of the ST and SM remained constant. These results suggest that the neural inhibitory mechanism might be involved in decreasing in maximal voluntary force and hamstring muscles activation toward the knee extension during high-velocity eccentric movement and therefore subjects have difficulties to maintain high eccentric force level throughout the motion. Moreover, the possible mechanism reducing the BF muscle activation as the knee approaches extension was architectural differences in the hamstring muscles, which might reflect each muscle's function.

  16. Spatial distribution of surface EMG on trapezius and lumbar muscles of violin and cello players in single note playing.

    Science.gov (United States)

    Afsharipour, Babak; Petracca, Francesco; Gasparini, Mauro; Merletti, Roberto

    2016-12-01

    Musicians activate their muscles in different patterns, depending on their posture, the instrument being played, and their experience level. Bipolar surface electrodes have been used in the past to monitor such activity, but this method is highly sensitive to the location of the electrode pair. In this work, the spatial distribution of surface EMG (sEMG) of the right trapezius and right and left erector spinae muscles were studied in 16 violin players and 11 cello players. Musicians played their instrument one string at a time in sitting position with/without backrest support. A 64 sEMG electrode (16×4) grid, 10mm inter-electrode distance (IED), was placed over the middle and lower trapezius (MT and LT) of the bowing arm. Two 16×2 electrode grids (IED=10mm) were placed on the left and right erector spinae muscles. Subjects played each of the four strings of the instrument either in large (1bow/s) or detaché tip/tail (8bows/s) bowing in two sessions (two days). In each of two days, measurements were repeated after half an hour of exercise to see the effect of exercise on the muscle activity and signal stability. A "muscle activity index" (MAI) was defined as the spatial average of the segmented active region of the RMS map. Spatial maps were automatically segmented using the watershed algorithm and thresholding. Results showed that, for violin players, sliding the bow upward from the tip toward the tail results in a higher MAI for the trapezius muscle than a downward bow. On the contrary, in cello players, higher MAI is produced in the tail to tip movement. For both instruments, an increasing MAI in the trapezius was observed as the string position became increasingly lateral, from string 1 (most medial) toward string 4 (most lateral). Half an hour of performance did not cause significant differences between the signal quality and the MAI values measured before and after the exercise. The MAI of the left and right erector spinae was smaller in the case of

  17. Differential effects of type of keyboard playing task and tempo on surface EMG amplitudes of forearm muscles

    Directory of Open Access Journals (Sweden)

    Hyun Ju eChong

    2015-09-01

    Full Text Available Despite increasing interest in keyboard playing as a strategy for repetitive finger exercises in fine motor skill development and hand rehabilitation, comparative analysis of task-specific finger movements relevant to keyboard playing has been less extensive. This study examined whether there were differences in surface EMG activity levels of forearm muscles associated with different keyboard playing tasks. Results demonstrated higher muscle activity with sequential keyboard playing in a random pattern compared to individuated playing or sequential playing in a successive pattern. Also, the speed of finger movements was found as a factor that affect muscle activity levels, demonstrating that faster tempo elicited significantly greater muscle activity than self-paced tempo. The results inform our understanding of the type of finger movements involved in different types of keyboard playing at different tempi so as to consider the efficacy and fatigue level of keyboard playing as an intervention for amateur pianists or individuals with impaired fine motor skills.

  18. Assessment of work-related muscle strain by using surface EMG during test contractions interposed between work periods of simulateted mushroom picking

    DEFF Research Database (Denmark)

    Ohashi, Jun-Ya; Blangsted, Anne Katrine; Nielsen, Pernille Kofoed

    2010-01-01

    Surface electromyograms(EMG) during test contractions (TCs) were studied to assess the muscle strain in simulated mushroom picking. Additionally, the duration of the TC for the effective assessment was investigated. Nine female subjects performed standardized shoulder abduction and a stooped post...... during the TCs. AEMG and MPF fluctuated before W1 although the changes of RPE were small. Averaging several TCs was recommended to get stable results from TCs. EMG changes and appropriate TC conditions were discussed in relation to the adaptation in fatiguing contractions....

  19. Assessment of work-related muscle strain by using surface EMG during test contractions interposed between work periods of simulateted mushroom picking

    DEFF Research Database (Denmark)

    Ohashi, Jun-Ya; Blangsted, Anne Katrine; Nielsen, Pernille Kofoed

    2010-01-01

    Surface electromyograms(EMG) during test contractions (TCs) were studied to assess the muscle strain in simulated mushroom picking. Additionally, the duration of the TC for the effective assessment was investigated. Nine female subjects performed standardized shoulder abduction and a stooped...

  20. Effect of a combined inversion and plantarflexion surface on ankle kinematics and EMG activities in landing

    Directory of Open Access Journals (Sweden)

    Divya Bhaskaran

    2015-12-01

    Conclusion: These findings suggest that compared to the inversion surface, the combined plantarflexion and inversion surface seems to provide a more unstable surface condition for lateral ankle sprains during landing.

  1. EMG (elektromyografie jako metoda pro sledování účinnosti sportovního tréninku Surface EMG as a method for following-up sports training efficiency

    Directory of Open Access Journals (Sweden)

    Damian Miklavčič

    2005-02-01

    Full Text Available Účel této studie byl zhodnotit vhodnost a použitelnost povrchové elektromyografie pro vyhodnocení změn kontrakčních vlastností svalů spojených s tréninkem. Skupina osmi národních juniorských tenistů se zúčastnila šestitýdenního výcvikového programu, který byl zaměřen na zvýšení rychlosti a výbušnosti. Jejich fyzické charakteristiky byly zhodnoceny před a po období programu, a to specifickými tenisovými testy, které měří izometrickou kontrakci trhnutí středního gastroknemického svalu, a zaznamenáváním spektra frekvence EMG při 50% maximální volní kontrakci. Ve specifických tenisových testech se prokázalo, že většina hráčů zlepšila své výkony po výcvikovém období, pouze u 3 hráčů byla zjištěna zvýšená rychlost kontrakce středního gastroknemického svalu, která byla vyjádřena kratší dobou kontrakčního trhnutí po období výcviku. Stejní hráči předvedli vyšší charakteristickou frekvenci (definována jako střední frekvence ležící mezi 6. a 9. decilem spektrální distribuční funkce a širší EMG spektrum rozkmitu po výcvikovém období. Vysoká korelace byla zjištěna mezi počtem parametrů izometrické kontrakce trhnutí, která byla zlepšena o více než 2 % po období výcviku (Np, poměr mezi charakteristickou frekvencí po období výcviku (fA a před výcvikovým obdobím (fB (fA/fB (p = 0,0065, a také mezi Np a stoupáním lineárního přiblížení závislosti mezi decilovými frekvencemi signálů EMG po období výcviku (dAf a před výcvikovým obdobím (dBf (dAf = f(dBf (p = 0,0035. Korelace mezi počtem parametrů izometrické kontrakce trhnutí, které byly zlepšeny po období výcviku, a změny v charakteristických parametrech EMG evokují použitelnost EMG pro sledování účinnosti sportovního výcviku. The purpose of the present study was to evaluate the applicability of surface electromyography (EMG for evaluation of

  2. Comparison of joint angles and electromyographic activity of the lower extremities during standing with wearing standard and revised high-heeled shoes: A pilot study.

    Science.gov (United States)

    Bae, Young-Hyeon; Ko, Mansoo; Lee, Suk Min

    2016-04-29

    Revised high-heeled shoes (HHSs) were designed to improve the shortcomings of standard HHSs. This study was conducted to compare revised and standard HHSs with regard to joint angles and electromyographic (EMG) activity of the lower extremities during standing. The participants were five healthy young women. Data regarding joint angles and EMG activity of the lower extremities were obtained under three conditions: barefoot, when wearing revised HHSs, and when wearing standard HHSs. Lower extremity joint angles in the three dimensional plane were confirmed using a VICON motion capture system. EMG activity of the lower extremities was measured using active bipolar surface EMG. Kruskal-Wallis one-way analysis of variance by rank applied to analyze differences during three standing conditions. Compared with the barefoot condition, the standard HHSs condition was more different than the revised HHSs condition with regard to lower extremity joint angles during standing. EMG activity of the lower extremities was different for the revised HHSs condition, but the differences among the three conditions were not significant. Wearing revised HHSs may positively impact joint angles and EMG activity of the lower extremities by improving body alignment while standing.

  3. Surface electromyographic analysis of core trunk and hip muscles during selected rehabilitation exercises in the side-bridge to neutral spine position.

    Science.gov (United States)

    Youdas, James W; Boor, Mallory M P; Darfler, Arynn L; Koenig, Margaret K; Mills, Katherine M; Hollman, John H

    2014-09-01

    Strengthening of core hip, trunk, and abdominal muscles has been utilized with injury prevention and low back pain and has the potential to improve athletic performance. During a side-bridge, trunk and thigh muscles on the ipsilateral weightbearing side would produce greater activation than their counterparts on the contralateral nonweightbearing side. Descriptive laboratory study. Twelve females and 13 males participated. Electromyography (EMG) signals were gathered for 5 right-sided muscles (rectus abdominis [RA], external oblique [EO], longissimus thoracis [LT], lumbar multifidus [LM], and gluteus medius [GM]) during 3 repetitions of 4 side-bridging exercises (trunk-elevated side support [TESS], foot-elevated side support [FESS], clamshell, and rotational side-bridge [RSB]) performed bilaterally in random order using surface electrodes. EMG signals were normalized to peak activity in maximum voluntary isometric contraction (MVIC) trials and expressed as a percentage. Descriptive EMG data were calculated for EMG recruitment (% MVIC) and compared between right side up and right side down conditions and between exercises with 2-way repeated-measures analyses of variance at α = 0.05. RSB created the most muscle activation in 3 of 4 recorded trunk muscles (RA, 43.9% MVIC; EO, 62.8 % MVIC; and LT, 41.3% MVIC). Activation of the GM exceeded 69% MVIC for TESS, FESS, and RSB. With the exception of the RA in RSB and LT in TESS, recruitment within muscles of the ipsilateral weightbearing trunk and thigh (% MVIC) was significantly greater than their counterparts on the nonweightbearing trunk and thigh for all muscles during the side-bridge exercise conditions. Muscle recruitment was greater within muscles of the ipsilateral weightbearing trunk and thigh for all examined muscles except RA during RSB and LT during TESS. Activation at or above 50% MVIC is needed for strengthening. Activation of the GM and EO meets these requirements. Side-bridge exercises appear to provide

  4. Electromyographic analysis of the gluteus medius in five weight-bearing exercises.

    Science.gov (United States)

    Krause, David A; Jacobs, Rebecca S; Pilger, Katie E; Sather, Becky R; Sibunka, Seth P; Hollman, John H

    2009-12-01

    Weight-bearing exercises are frequently used to train and strengthen muscles of the hip. These exercises have been advocated in the rehabilitation of a variety of hip and knee dysfunctions. Limited evidence is available to describe the level of muscle activation occurring with specific weight-bearing exercises. The purpose of this study was to investigate the level of activation of the gluteus medius muscle as measured by electromyographic (EMG) signal amplitude in 5 weight-bearing exercises. Twenty healthy subjects aged 21 to 30 years participated in the study. The EMG surface electrodes were positioned over the muscle belly of the gluteus medius. Subjects performed 5 exercises that consisted of bilateral stance, single limb stance, single limb stance on both a firm surface and an Airex cushion, and single limb squat on a firm surface and an Airex cushion. Statistical differences (rho gluteus medius EMG values were found between single limb stance as compared with double limb stance, and single limb squat as compared with single limb stance. Single limb stance places more demands on the gluteus medius than double limb stance, whereas single limb squats are more demanding than single limb stance. Although exercises performed on an Airex cushion produced greater EMG values as compared with a firm surface, the difference was not statistically significant. The results, however, suggest that if the goal is to increase the challenge to the gluteus medius, dynamic, single limb exercises performed on unstable surfaces, such as a balance cushion, may place greater demands on the gluteus medius than similar exercises performed on stable surfaces.

  5. Comparison of the EMG Activities in the Vastus Medialis Oblique ...

    African Journals Online (AJOL)

    The purpose of this study was to compare the electromyographic (EMG) activities in the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles during two open chain exercises commonly used in the management of patellofemoral pain syndrome (PFPS). Twenty-five (14 female and 11 male) healthy subjects ...

  6. EMG biofeedback of the abductor pollicis brevis in piano performance.

    Science.gov (United States)

    Montes, R; Bedmar, M; Sol Martin, M

    1993-06-01

    The aim of the present study was to apply EMG biofeedback as an auxiliary to piano teaching techniques. We studied the changes in integrated electromyographic activity, using the abductor pollicis brevis functioning as an agonist during the teaching of identical selective movements of piano playing in two groups, one with EMG biofeedback and the other following traditional method of instruction. The analysis of variance revealed an increase in the peak amplitude and the relaxation rate values for the biofeedback group. These results have implications for the application of piano playing techniques and reveal EMG biofeedback as an aid in the teaching of thumb attack with the abductor pollicis brevis as agonist.

  7. Locomotor training with body weight support in SCI : EMG improvement is more optimally expressed at a low testing speed

    NARCIS (Netherlands)

    Meyns, P.; Van de Crommert, H. W. A. A.; Rijken, H.; van Kuppevelt, D. H. J. M.; Duysens, J.

    2014-01-01

    Study design: Case series. Objectives: To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Setting: Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands.

  8. Robust functional statistics applied to Probability Density Function shape screening of sEMG data.

    Science.gov (United States)

    Boudaoud, S; Rix, H; Al Harrach, M; Marin, F

    2014-01-01

    Recent studies pointed out possible shape modifications of the Probability Density Function (PDF) of surface electromyographical (sEMG) data according to several contexts like fatigue and muscle force increase. Following this idea, criteria have been proposed to monitor these shape modifications mainly using High Order Statistics (HOS) parameters like skewness and kurtosis. In experimental conditions, these parameters are confronted with small sample size in the estimation process. This small sample size induces errors in the estimated HOS parameters restraining real-time and precise sEMG PDF shape monitoring. Recently, a functional formalism, the Core Shape Model (CSM), has been used to analyse shape modifications of PDF curves. In this work, taking inspiration from CSM method, robust functional statistics are proposed to emulate both skewness and kurtosis behaviors. These functional statistics combine both kernel density estimation and PDF shape distances to evaluate shape modifications even in presence of small sample size. Then, the proposed statistics are tested, using Monte Carlo simulations, on both normal and Log-normal PDFs that mimic observed sEMG PDF shape behavior during muscle contraction. According to the obtained results, the functional statistics seem to be more robust than HOS parameters to small sample size effect and more accurate in sEMG PDF shape screening applications.

  9. Effect of hypnosis on masseter EMG recorded during the 'resting' and a slightly open jaw posture.

    Science.gov (United States)

    Al-Enaizan, N; Davey, K J; Lyons, M F; Cadden, S W

    2015-11-01

    The aim of this experimental study was to determine whether minimal levels of electromyographic activity in the masseter muscle are altered when individuals are in a verified hypnotic state. Experiments were performed on 17 volunteer subjects (8 male, 9 female) all of whom gave informed consent. The subjects were dentate and had no symptoms of pain or masticatory dysfunction. Surface electromyograms (EMGs) were made from the masseter muscles and quantified by integration following full-wave rectification and averaging. The EMGs were obtained (i) with the mandible in 'resting' posture; (ii) with the mandible voluntarily lowered (but with the lips closed); (iii) during maximum voluntary clenching (MVC). The first two recordings were made before, during and after the subjects were in a hypnotic state. Susceptibility to hypnosis was assessed with Spiegel's eye-roll test, and the existence of the hypnotic state was verified by changes in ventilatory pattern. On average, EMG levels expressed as percentages of MVC were less: (i) when the jaw was deliberately lowered as opposed to being in the postural position: (ii) during hypnosis compared with during the pre- and post-hypnotic periods. However, analysis of variance followed by post hoc tests with multiple comparison corrections (Bonferroni) revealed that only the differences between the level during hypnosis and those before and after hypnosis were statistically significant (P hypnosis, it appears that part of that EMG is of biological origin. © 2015 John Wiley & Sons Ltd.

  10. Effect of sex on torque, recovery, EMG, and MMG responses to fatigue

    Science.gov (United States)

    Hill, E.C.; Housh, T.J.; Smith, C.M.; Cochrane, K.C.; Jenkins, N.D.M.; Cramer, J.T.; Schmidt, R.J.; Johnson, G.O.

    2016-01-01

    Objective: The purpose of the present investigation was to examine the effect of sex on maximal voluntary isometric contraction (MVIC) torque and the EMG and MMG responses as a result of fatiguing, intermittent, submaximal (65% of MVIC), isometric elbow flexion muscle contractions. Methods: Eighteen men and women performed MVIC trials before (pretest), after (posttest), and 5-min after (5-min recovery) performing 50 intermittent, submaximal isometric muscle contractions. Surface electromyographic (EMG) and mechanomyographic (MMG) signals were simultaneously recorded from the biceps brachii muscle. Results: As a result of the fatiguing workbout torque decreased similarly from pretest to posttest for both the men (24.0%) and women (23.3%). After 5-min of recovery, torque had partially recovered for the men, while torque had returned to pretest levels for the women. For both sexes, from pretest to posttest EMG mean power frequency and MMG amplitude decreased, but returned to pretest levels after 5-min of recovery. Conclusions: In the present study, there were sex-related differences in muscle fatigue that were not associated with the EMG or MMG responses. PMID:27973383

  11. The electromyographic threshold in boys and men.

    Science.gov (United States)

    Pitt, Brynlynn; Dotan, Raffy; Millar, Jordan; Long, Devon; Tokuno, Craig; O'Brien, Thomas; Falk, Bareket

    2015-06-01

    Children have been shown to have higher lactate (LaTh) and ventilatory (VeTh) thresholds than adults, which might be explained by lower levels of type-II motor-unit (MU) recruitment. However, the electromyographic threshold (EMGTh), regarded as indicating the onset of accelerated type-II MU recruitment, has been investigated only in adults. To compare the relative exercise intensity at which the EMGTh occurs in boys versus men. Participants were 21 men (23.4 ± 4.1 years) and 23 boys (11.1 ± 1.1 years), with similar habitual physical activity and peak oxygen consumption (VO2pk) (49.7 ± 5.5 vs. 50.1 ± 7.4 ml kg(-1) min(-1), respectively). Ramped cycle ergometry was conducted to volitional exhaustion with surface EMG recorded from the right and left vastus lateralis muscles throughout the test (~10 min). The composite right-left EMG root mean square (EMGRMS) was then calculated per pedal revolution. The EMGTh was then determined as the exercise intensity at the point of least residual sum of squares for any two regression line divisions of the EMGRMS plot. EMGTh was detected in 20/21 of the men (95.2 %) and only in 18/23 of the boys (78.3 %). The boys' EMGTh was significantly higher than the men's (86.4 ± 9.6 vs. 79.7 ± 10.0 % of peak power output at exhaustion; p boys' higher EMGTh suggests delayed and hence lesser utilization of type-II MUs in progressive exercise, compared with men. The boys-men EMGTh differences were of similar magnitude as those shown for LaTh and VeTh, further suggesting a common underlying factor.

  12. Muscular Activities Measurements of Forward Lean and Upright Sitting Motorcycling Postures via Surface Electromyography (sEMG

    Directory of Open Access Journals (Sweden)

    Ma’arof Muhammad Izzat Nor

    2017-01-01

    Full Text Available Motorcycling postures are generically speculated to be physical and physiologically demanding – which in-turn may lead to motorcycling fatigue, and then becoming a possible factor to road accident. The objective of this study was to measure the muscular activities of various motorcycling postures. High muscular activity reading will signifies that motorcycling is indeed physically and physiologically demanding to the motorcyclist. For this particular study, the following postures were tested: i forward lean, ii upright sitting, and iii neutral sitting (as control. Surface electromyography (sEMG measurement was conducted on the following muscles: i extensor carpi radialis, ii upper trapezius iii latissimus dorsi, and iv erector spinae. The results showed that for all test subjects, the muscular activities readings for the forward lean posture was actually close to neutral sitting’s. Whilst, the upright sitting had showed much higher muscular activities measurement instead. Conclusively, this study had proven that any types of discomforts associated with the forward lean posture is not originated from muscular activities. Whereas, confirming that any discomforts in regards to the upright sitting is indeed related to muscular activities. Further studies are warranted to discover the actual risk factors that causes physical and physiological discomforts for the forward lean motorcycling posture.

  13. ECG artifact cancellation in surface EMG signals by fractional order calculus application.

    Science.gov (United States)

    Miljković, Nadica; Popović, Nenad; Djordjević, Olivera; Konstantinović, Ljubica; Šekara, Tomislav B

    2017-03-01

    New aspects for automatic electrocardiography artifact removal from surface electromyography signals by application of fractional order calculus in combination with linear and nonlinear moving window filters are explored. Surface electromyography recordings of skeletal trunk muscles are commonly contaminated with spike shaped artifacts. This artifact originates from electrical heart activity, recorded by electrocardiography, commonly present in the surface electromyography signals recorded in heart proximity. For appropriate assessment of neuromuscular changes by means of surface electromyography, application of a proper filtering technique of electrocardiography artifact is crucial. A novel method for automatic artifact cancellation in surface electromyography signals by applying fractional order calculus and nonlinear median filter is introduced. The proposed method is compared with the linear moving average filter, with and without prior application of fractional order calculus. 3D graphs for assessment of window lengths of the filters, crest factors, root mean square differences, and fractional calculus orders (called WFC and WRC graphs) have been introduced. For an appropriate quantitative filtering evaluation, the synthetic electrocardiography signal and analogous semi-synthetic dataset have been generated. The examples of noise removal in 10 able-bodied subjects and in one patient with muscle dystrophy are presented for qualitative analysis. The crest factors, correlation coefficients, and root mean square differences of the recorded and semi-synthetic electromyography datasets showed that the most successful method was the median filter in combination with fractional order calculus of the order 0.9. Statistically more significant (p ECG peak reduction was obtained by the median filter application compared to the moving average filter in the cases of low level amplitude of muscle contraction compared to ECG spikes. The presented results suggest that the

  14. Electromyographic Analysis of the Triceps Surae Muscle Complex During Achilles Tendon Rehabilitation Program Exercises

    Science.gov (United States)

    Mullaney, Michael; Tyler, Timothy F.; McHugh, Malachy; Orishimo, Karl; Kremenic, Ian; Caggiano, Jessica; Ramsey, Abi

    2011-01-01

    Background: Specific guidelines for therapeutic exercises following an Achilles tendon repair are lacking. Hypothesis: A hierarchical progression of triceps surae exercises can be determined on the basis of electromyographic (EMG) activity. Study Design: Randomized laboratory trial. Methods: Bipolar surface electrodes were applied over the medial and lateral heads of the gastrocnemius as well as the soleus on 20 healthy lower extremities (10 participants, 27 ± 5 years old). Muscle activity was recorded during 8 therapeutic exercises commonly used following an Achilles repair. Maximal voluntary isometric contractions (MVICs) were also performed on an isokinetic device. The effect of exercise on EMG activity (% MVIC) was assessed using repeated measures analysis of variance with Bonferroni corrections for planned pairwise comparisons. Results: Seated toe raises (11% MVIC) had the least amount of activity compared with all other exercises (P < 0.01), followed by single-leg balance on wobble board (25% MVIC), prone ankle pumps (38% MVIC), supine plantarflexion with red elastic resistance (45% MVIC), normal gait (47% MVIC), lateral step-ups (60% MVIC), single-leg heel raises (112% MVIC), and single-leg jumping (129% MVIC). Conclusion: There is an increasing progression of EMG activity for exercises that target the triceps surae muscle complex during common exercises prescribed in an Achilles tendon rehabilitation program. Seated toe raises offer relatively low EMG activity and can be utilized as an early rehabilitative exercise. In contrast, the single-leg heel raise and single-leg jumping should be utilized only during later-stage rehabilitation. Clinical Relevance: EMG activity in the triceps surae is variable with common rehab exercises. PMID:23016056

  15. Design and assessment of a low-cost, electromyographically controlled, prosthetic hand

    Directory of Open Access Journals (Sweden)

    Polisiero M

    2013-06-01

    Full Text Available Massimo Polisiero,1 Paolo Bifulco,1 Annalisa Liccardo,2 Mario Cesarelli,1 Maria Romano,1 Gaetano D Gargiulo,3 Alistair L McEwan,3 Massimo D'Apuzzo2 1Department of Biomedical, Electronics and Telecommunication Engineering, 2Department of Electrical Engineering, University Federico II of Naples, Naples, Italy; 3School of Electrical and Information Engineering, The University of Sydney, New South Wales, Australia Abstract: The study reported here explored the design and realization of a low-cost, electromyographically controlled hand prosthesis for amputees living in developing countries. The developed prosthesis is composed of a light aluminum structure with opposing fingers connected to a DC motor that imparts only the movement of grasp. Problems associated with surface electromyographic signal acquisition and processing, motor control, and evaluation of grasp force were addressed, with the goal of minimizing cost and ensuring easy assembly. Simple analog front ends amplify and condition the electromyographic signals registered from two antagonist muscles by surface electrodes. Analog signals are sampled at 1 kHz and processed by a microcontroller that drives the motor with a supply voltage proportional to the muscular contraction, performing the opening and closing of the opposing fingers. Reliable measurements of the level of muscle contractions were obtained by specific digital processing: real-time operators implementing the root mean square value, mean absolute value, standard deviation, and mean absolute differential value were compared in terms of efficiency to estimate the EMG envelope, computational load, and time delay. The mean absolute value operator was adopted at a time window of 64 milliseconds. A suitable calibration procedure was proposed to overcome problems associated with the wide variation of electromyograph amplitude and background noise depending on the specific patient's muscles selected. A pulse-width modulated signal

  16. Timing of electromyographic activity and ranges of motion during simple motor tasks of upper extremities

    Directory of Open Access Journals (Sweden)

    Syczewska Małgorzata

    2017-10-01

    Full Text Available Study aim: Improvement of the upper extremities’ performance is one of the key aims in the rehabilitation process. In order to achieve high effectiveness of this process the amount of functional improvement achieved by a patient during the therapy needs to be assessed. The aim of this study was to obtain electromyographic (EMG activity profiles of the upper extremity muscles during execution of simple tasks in healthy subjects. Additionally the ranges of wrist, elbow and shoulder joints were measured and reported during performed trials. The second aim was to determine whether the movement execution and ranges of move­ments and muscular activity depend on age. Material and methods: Twenty-eight healthy adults, age range 21 to 65 years old, participated in the study. Surface electrodes were placed bilaterally on 7 upper extremity muscles. To obtain information about the beginning and end of the movement task and ranges of upper extremity joints, 13 markers were placed on the elbows and wrists of both upper extremities. The move­ments of the segments were calculated (distal vs proximal in five simple functional tasks (each task involved only one joint, performed while sitting. Kinematic data were collected by the VICON 460 system, and electromyographic data with the Mo­tion Lab EMG system. Results: Charts of timing of EMG activity of the upper extremity muscles together with ranges of upper extremity joint motion were obtained. Conclusion: The results show that the number of muscles activated and the time (or percentage of the task during which they are active depend on the type of the task and age. These data can be used as a reference in evaluation of functional deficits of patients.

  17. Local muscle endurance is associated with fatigue-based changes in electromyographic spectral properties, but not with conduction velocity.

    Science.gov (United States)

    Beck, Travis W; Ye, Xin; Wages, Nathan P

    2015-06-01

    The purpose of this study was to examine the associations amongst muscle fiber action potential conduction velocity (CV), spectral characteristics of the surface electromyographic (EMG) signal, and endurance time during a sustained submaximal isometric muscle action. Eleven men (mean±SD age=23±4yrs) performed a sustained, submaximal isometric muscle action of the dominant forearm flexors at 60% of the maximum voluntary contraction (MVC) until the designated force level could no longer be maintained. Sixteen separate bipolar surface EMG signals were detected from the biceps brachii with a linear electrode array during this contraction. Two channels from this array were used to measure CV, and one of these two channels was used for further EMG signal processing. The channels that provided the highest signal quality were used for the CV measurements and further data analysis. A wavelet analysis was then used to analyze the bipolar EMG signal, and the resulting wavelet spectrum was decomposed with a nonparametric spectral decomposition procedure. The results showed that the time to exhaustion during the sustained contraction was not correlated with the rate of decrease in CV, but it was highly correlated with both the decrease in high-frequency spectral power (r=0.947) and the increase in low-frequency spectral power (r=0.960). These findings are particularly interesting, considering that the decrease in traditional EMG spectral variables (e.g., mean frequency or median frequency) with fatigue is generally attributed to reductions in CV. While this may indeed be true, the present results suggested that other factors (i.e., other than CV) that can affect the shape of the EMG frequency spectrum during fatigue are more important in determining the endurance capabilities of the muscle than is CV. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Abdominal muscle EMG-activity during bridge exercises on stable and unstable surfaces.

    Science.gov (United States)

    Czaprowski, Dariusz; Afeltowicz, Anna; Gębicka, Anna; Pawłowska, Paulina; Kędra, Agnieszka; Barrios, Carlos; Hadała, Michał

    2014-08-01

    To assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball). Prospective comparison study. Research laboratory. Thirty-three healthy volunteers from a university population. Surface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA). The AM exhibited the highest activity during prone bridge on a Swiss Ball (RA, EO, IO-TA 44.7 ± 19.2, 54.7 ± 22.9, 36.8 ± 18.6 in % of MVC, respectively). The lowest activity was observed during supine bridge on a stable surface and a BOSU (under 5.0). The lowest ratio analyzed on the basis of the relation of EO and IO-TA activity to RA was obtained during prone bridge on the Swiss Ball (1.4 ± 0.7 for EO, 0.9 ± 0.5 for IO-TA). The highest ratio was obtained during prone bridge on stable surface and supine bridges. The highest level of activity in the abdominal muscles is achieved during prone bridge on a Swiss Ball. However, this exercise provided the lowest activity of the EO and IO-TA in relation to RA. It is essential to conduct further studies verifying the usefulness of using Swiss Ball during core stability training. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Comparison of analysis techniques for electromyographic data.

    Science.gov (United States)

    Johnson, J C

    1978-01-01

    Electromyography has been effectively employed to estimate the stress encountered by muscles in performing a variety of functions in the static environment. Such analysis provides the basis for modification of a man-machine system in order to optimize the performances of individual tasks by reducing muscle stress. Myriad analysis methods have been proposed and employed to convert raw electromyographic data into numerical indices of stress and, more specifically, muscle work. However, the type of analysis technique applied to the data can significantly affect the outcome of the experiment. In this study, four methods of analysis are employed to simultaneously process electromyographic data from the flexor muscles of the forearm. The methods of analysis include: 1) integrated EMG (three separate time constants), 2) root mean square voltage, 3) peak height discrimination (three level), and 4) turns counting (two methods). Mechanical stress input as applied to the arm of the subjects includes static load and vibration. The results of the study indicate the comparative sensitivity of each of the techniques to changes in EMG resulting from changes in static and dynamic load on the muscle.

  20. Electromyographic evaluation of the upper lip according to the breathing mode: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Aldrieli Regina Ambrosio

    2009-12-01

    Full Text Available The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB or mouth (PMB breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1, period 2 (P2 and the variation between periods (Δ did not reveal statistically significant differences between groups (p < 0.05. However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.

  1. Electromyographical Comparison of Muscle Activation Patterns Across Three Commonly Performed Kettlebell Exercises.

    Science.gov (United States)

    Lyons, Brian C; Mayo, Jerry J; Tucker, W Steven; Wax, Ben; Hendrix, Russell C

    2017-09-01

    Lyons, BC, Mayo, JJ, Tucker, WS, Wax, B, and Hendrix, RC. Electromyographical comparison of muscle activation patterns across 3 commonly performed kettlebell exercises. J Strength Cond Res 31(9): 2363-2370, 2017-The purpose of this study was to compare the muscle activation patterns of 3 different kettlebell (KB) exercises using electromyography (EMG). Fourteen resistance-trained subjects completed a 1-arm swing (Swing), 1-arm swing style snatch (Snatch), and a 1-arm clean (Clean) using a self-selected 8 to 10 repetition maximum load for each exercise. Trial sessions consisted of subjects performing 5 repetitions of each KB exercise. Mean EMG was used to assess the muscle activation of the biceps brachii, anterior deltoid, posterior deltoid, erector spinae (ES), vastus lateralis (VL), biceps femoris, contralateral external oblique (EO), and gluteus maximus during each lift using surface electrodes. The mean EMG was normalized using maximal voluntary contractions obtained from manual muscle testing. Repeated-measures analysis of variance revealed a significant difference in the muscle activation patterns of the ES (Swing > Snatch), EO (Snatch, Clean > Swing), and VL (Swing > Clean) across the 3 KB exercises. We conclude that although the KB Swing, Snatch, and Clean are total body exercises, they place different demands on the ES, contralateral EO, and the VL. Therefore, KBs represent an authentic alternative for lifters, and the Swing, Snatch, and Clean are not redundant exercises.

  2. Electromyographical Comparison of Four Common Shoulder Exercises in Unstable and Stable Shoulders

    Directory of Open Access Journals (Sweden)

    Aaron Sciascia

    2012-01-01

    Full Text Available This study examines if electromyographic (EMG amplitude differences exist between patients with shoulder instability and healthy controls performing scaption, prone horizontal abduction, prone external rotation, and push-up plus shoulder rehabilitation exercises. Thirty nine subjects were categorized by a single orthopedic surgeon as having multidirectional instability (n=10, anterior instability (n=9, generalized laxity (n=10, or a healthy shoulder (n=10. Indwelling and surface electrodes were utilized to measure EMG activity (reported as a % of maximum voluntary isometric contraction (MVIC in various shoulder muscles during 4 common shoulder exercises. The exercises studied effectively activated the primary musculature targeted in each exercise equally among all groups. The serratus anterior generated high activity (50–80% MVIC during a push-up plus, while the infraspinatus and teres major generated moderate-to-high activity (30–80% MVIC during both the prone horizontal and prone external rotation exercises. Scaption exercise generated moderate activity (20–50% MVIC in both rotator cuff and scapular musculature. Clinicians should feel confident in prescribing these shoulder-strengthening exercises in patients with shoulder instability as the activation levels are comparable to previous findings regarding EMG amplitudes and should improve the dynamic stabilization capability of both rotator cuff and scapular muscles using exercises designed to address glenohumeral joint instability.

  3. Comparison of electromyographic activity and range of neck motion in violin students with and without neck pain during playing.

    Science.gov (United States)

    Park, Kyue-nam; Kwon, Oh-yun; Ha, Sung-min; Kim, Su-jung; Choi, Hyun-jung; Weon, Jong-hyuck

    2012-12-01

    Neck pain is common in violin students during a musical performance. The purpose of this study was to compare electromyographic (EMG) activity in superficial neck muscles with neck motion when playing the violin as well as neck range of motion (ROM) at rest, between violin students with and without neck pain. Nine violin students with neck pain and nine age- and gender-matched subjects without neck pain were recruited. Muscle activity of the bilateral upper trapezius, sternocleidomastoid, and superficial cervical extensor muscles was measured using surface EMG. Kinematic data on neck motion while playing and active neck ROM were also measured using a three-dimensional motion analysis system. Independent t-tests were used to compare EMG activity with kinematic data between groups. These analyses revealed that while playing, both the angle of left lateral bending and leftward rotation of the cervical spine were significantly greater in the neck pain group than among those without neck pain. Similarly, EMG activity of the left upper trapezius, both cervical extensors, and both sternocleidomastoid muscles were significantly greater in the neck pain group. The active ROM of left axial rotation was significantly lower in the neck pain group. These results suggest that an asymmetric playing posture and the associated increased muscle activity as well as decreased neck axial rotation may contribute to neck pain in violin students.

  4. Computed myography: three-dimensional reconstruction of motor functions from surface EMG data

    International Nuclear Information System (INIS)

    Doel, Kees van den; Ascher, Uri M; Pai, Dinesh K

    2008-01-01

    We describe a methodology called computed myography to qualitatively and quantitatively determine the activation level of individual muscles by voltage measurements from an array of voltage sensors on the skin surface. A finite element model for electrostatics simulation is constructed from morphometric data. For the inverse problem, we utilize a generalized Tikhonov regularization. This imposes smoothness on the reconstructed sources inside the muscles and suppresses sources outside the muscles using a penalty term. Results from experiments with simulated and human data are presented for activation reconstructions of three muscles in the upper arm (biceps brachii, bracialis and triceps). This approach potentially offers a new clinical tool to sensitively assess muscle function in patients suffering from neurological disorders (e.g., spinal cord injury), and could more accurately guide advances in the evaluation of specific rehabilitation training regimens

  5. Computed myography: three-dimensional reconstruction of motor functions from surface EMG data

    Science.gov (United States)

    van den Doel, Kees; Ascher, Uri M.; Pai, Dinesh K.

    2008-12-01

    We describe a methodology called computed myography to qualitatively and quantitatively determine the activation level of individual muscles by voltage measurements from an array of voltage sensors on the skin surface. A finite element model for electrostatics simulation is constructed from morphometric data. For the inverse problem, we utilize a generalized Tikhonov regularization. This imposes smoothness on the reconstructed sources inside the muscles and suppresses sources outside the muscles using a penalty term. Results from experiments with simulated and human data are presented for activation reconstructions of three muscles in the upper arm (biceps brachii, bracialis and triceps). This approach potentially offers a new clinical tool to sensitively assess muscle function in patients suffering from neurological disorders (e.g., spinal cord injury), and could more accurately guide advances in the evaluation of specific rehabilitation training regimens.

  6. Electromyographic Study of a Sequence of Yau-Man Kung Fu Palm Strikes with and without Impact.

    Science.gov (United States)

    Neto, Osmar Pinto; Magini, Marcio; Pacheco, Marcos T T

    2007-01-01

    IN MARTIAL ARTS AND CONTACT SPORTS, STRIKES ARE OFTEN TRAINED IN TWO DIFFERENT WAYS: with and without impacts. This study aims to compare the electromyographical activity (EMG) of the triceps brachii (TB), biceps brachii (BB) and brachioradialis (BR) muscles during strikes with and without impacts. Eight Yau-Man Kung Fu practitioners participated in the experiment. Each participant performed 5 sequences of 5 consecutive KF Yau-Man palm strikes with no impact intercalated with 5 sequences of 5 repetitions targeting a KF training shield. Surface EMG signals were obtained from the TB, BB, and RB for 3.0 seconds using an eight-channel module with a total amplifier gain of 2000 and sampled at 3500 Hz. The EMG analyses were done in the time (rms) and frequency (wavelet) domains. For the frequency domain, Morlet wavelet power spectra were obtained and an original method was used to quantify statistically significant regions on the power spectra. The results both in the time and frequency domains indicate a higher TB and BR muscle activity for the strikes with impacts. No significant difference was found for the BB in the two different scenarios. In addition, the results show that the wavelet power spectra pattern for the three analysed muscles obtained from the strikes with and without impacts were similar. Key pointsEMG analysis of a sequence of Kung Fu strikes demonstrates higher Triceps Brachii and Brachioradialis muscle activity for strikes with impact than strikes without impact.An original reliable method for quantifying EMG wavelet transform results is presented.EMG wavelet power spectra describe muscle roles during a Kung Fu sequence of strikes.

  7. Surface-EMG analysis for the quantification of thigh muscle dynamic co-contractions during normal gait.

    Science.gov (United States)

    Strazza, Annachiara; Mengarelli, Alessandro; Fioretti, Sandro; Burattini, Laura; Agostini, Valentina; Knaflitz, Marco; Di Nardo, Francesco

    2017-01-01

    The research purpose was to quantify the co-contraction patterns of quadriceps femoris (QF) vs. hamstring muscles during free walking, in terms of onset-offset muscular activation, excitation intensity, and occurrence frequency. Statistical gait analysis was performed on surface-EMG signals from vastus lateralis (VL), rectus femoris (RF), and medial hamstrings (MH), in 16315 strides walked by 30 healthy young adults. Results showed full superimpositions of MH with both VL and RF activity from terminal swing, 80 to 100% of gait cycle (GC), to the successive loading response (≈0-15% of GC), in around 90% of the considered strides. A further superimposition was detected during the push-off phase both between VL and MH activation intervals (38.6±12.8% to 44.1±9.6% of GC) in 21.9±13.6% of strides, and between RF and MH activation intervals (45.9±5.3% to 50.7±9.7 of GC) in 32.7±15.1% of strides. These findings led to identify three different co-contractions among QF and hamstring muscles during able-bodied walking: in early stance (in ≈90% of strides), in push-off (in 25-30% of strides) and in terminal swing (in ≈90% of strides). The co-contraction in terminal swing is the one with the highest levels of muscle excitation intensity. To our knowledge, this analysis represents the first attempt for quantification of QF/hamstring muscles co-contraction in young healthy subjects during normal gait, able to include the physiological variability of the phenomenon. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping.

    Science.gov (United States)

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R; Hamm, Thomas M; Santello, Marco

    2010-12-01

    Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible. The coordination of 12 hand muscles was quantified as electromyographic (EMG) muscle activation pattern (MAP) vector and EMG-EMG coherence. We hypothesized that muscle fatigue would cause uniform changes in EMG amplitude across all muscles and an increase in EMG-EMG coherence in the higher frequency bands but with an invariant heterogeneous distribution across muscles. Muscle fatigue caused a 12.5% drop in the maximum voluntary contraction force (P EMG amplitude of all muscles increased during the fatiguing contraction (P muscle coordination pattern was used throughout the fatiguing contraction. Last, EMG-EMG coherence (0-35 Hz) was significantly greater at the end than at the beginning of the fatiguing contraction (P muscles. These findings suggest that similar mechanisms are involved for modulating and sustaining digit forces in nonfatiguing and fatiguing contractions, respectively.

  9. A Simple Network to Remove Interference in Surface EMG Signal from Single Gene Affected Phenylketonuria Patients for Proper Diagnosis

    Science.gov (United States)

    Mohanty, Madhusmita; Basu, Mousumi; Pattanayak, Deba Narayan; Mohapatra, Sumant Kumar

    2018-04-01

    Recently Autosomal Recessive Single Gene (ARSG) diseases are highly effective to the children within the age of 5-10 years. One of the most ARSG disease is a Phenylketonuria (PKU). This single gene disease is associated with mutations in the gene that encodes the enzyme phenylalanine hydroxylase (PAH, Gene 612349). Through this mutation process, PAH of the gene affected patient can not properly manufacture PAH as a result the patients suffer from decreased muscle tone which shows abnormality in EMG signal. Here the extraction of the quality of the PKU affected EMG (PKU-EMG) signal is a keen interest, so it is highly necessary to remove the added ECG signal as well as the biological and instrumental noises. In the Present paper we proposed a method for detection and classification of the PKU affected EMG signal. Here Discrete Wavelet Transformation is implemented for extraction of the features of the PKU affected EMG signal. Adaptive Neuro-Fuzzy Inference System (ANFIS) network is used for the classification of the signal. Modified Particle Swarm Optimization (MPSO) and Modified Genetic Algorithm (MGA) are used to train the ANFIS network. Simulation result shows that the proposed method gives better performance as compared to existing approaches. Also it gives better accuracy of 98.02% for the detection of PKU-EMG signal. The advantages of the proposed model is to use MGA and MPSO to train the parameters of ANFIS network for classification of ECG and EMG signal of PKU affected patients. The proposed method obtained the high SNR (18.13 ± 0.36 dB), SNR (0.52 ± 1.62 dB), RE (0.02 ± 0.32), MSE (0.64 ± 2.01), CC (0.99 ± 0.02), RMSE (0.75 ± 0.35) and MFRE (0.01 ± 0.02), RMSE (0.75 ± 0.35) and MFRE (0.01 ± 0.02). From authors knowledge, this is the first time a composite method is used for diagnosis of PKU affected patients. The accuracy (98.02%), sensitivity (100%) and specificity (98.59%) helps for proper clinical treatment. It can help for readers

  10. A Simple Network to Remove Interference in Surface EMG Signal from Single Gene Affected Phenylketonuria Patients for Proper Diagnosis

    Science.gov (United States)

    Mohanty, Madhusmita; Basu, Mousumi; Pattanayak, Deba Narayan; Mohapatra, Sumant Kumar

    2018-01-01

    Recently Autosomal Recessive Single Gene (ARSG) diseases are highly effective to the children within the age of 5-10 years. One of the most ARSG disease is a Phenylketonuria (PKU). This single gene disease is associated with mutations in the gene that encodes the enzyme phenylalanine hydroxylase (PAH, Gene 612349). Through this mutation process, PAH of the gene affected patient can not properly manufacture PAH as a result the patients suffer from decreased muscle tone which shows abnormality in EMG signal. Here the extraction of the quality of the PKU affected EMG (PKU-EMG) signal is a keen interest, so it is highly necessary to remove the added ECG signal as well as the biological and instrumental noises. In the Present paper we proposed a method for detection and classification of the PKU affected EMG signal. Here Discrete Wavelet Transformation is implemented for extraction of the features of the PKU affected EMG signal. Adaptive Neuro-Fuzzy Inference System (ANFIS) network is used for the classification of the signal. Modified Particle Swarm Optimization (MPSO) and Modified Genetic Algorithm (MGA) are used to train the ANFIS network. Simulation result shows that the proposed method gives better performance as compared to existing approaches. Also it gives better accuracy of 98.02% for the detection of PKU-EMG signal. The advantages of the proposed model is to use MGA and MPSO to train the parameters of ANFIS network for classification of ECG and EMG signal of PKU affected patients. The proposed method obtained the high SNR (18.13 ± 0.36 dB), SNR (0.52 ± 1.62 dB), RE (0.02 ± 0.32), MSE (0.64 ± 2.01), CC (0.99 ± 0.02), RMSE (0.75 ± 0.35) and MFRE (0.01 ± 0.02), RMSE (0.75 ± 0.35) and MFRE (0.01 ± 0.02). From authors knowledge, this is the first time a composite method is used for diagnosis of PKU affected patients. The accuracy (98.02%), sensitivity (100%) and specificity (98.59%) helps for proper clinical treatment. It can help for readers

  11. Design and assessment of a low-cost, electromyographically controlled, prosthetic hand.

    Science.gov (United States)

    Polisiero, Massimo; Bifulco, Paolo; Liccardo, Annalisa; Cesarelli, Mario; Romano, Maria; Gargiulo, Gaetano D; McEwan, Alistair L; D'Apuzzo, Massimo

    2013-01-01

    The study reported here explored the design and realization of a low-cost, electromyographically controlled hand prosthesis for amputees living in developing countries. The developed prosthesis is composed of a light aluminum structure with opposing fingers connected to a DC motor that imparts only the movement of grasp. Problems associated with surface electromyographic signal acquisition and processing, motor control, and evaluation of grasp force were addressed, with the goal of minimizing cost and ensuring easy assembly. Simple analog front ends amplify and condition the electromyographic signals registered from two antagonist muscles by surface electrodes. Analog signals are sampled at 1 kHz and processed by a microcontroller that drives the motor with a supply voltage proportional to the muscular contraction, performing the opening and closing of the opposing fingers. Reliable measurements of the level of muscle contractions were obtained by specific digital processing: real-time operators implementing the root mean square value, mean absolute value, standard deviation, and mean absolute differential value were compared in terms of efficiency to estimate the EMG envelope, computational load, and time delay. The mean absolute value operator was adopted at a time window of 64 milliseconds. A suitable calibration procedure was proposed to overcome problems associated with the wide variation of electromyograph amplitude and background noise depending on the specific patient's muscles selected. A pulse-width modulated signal drives the DC motor, allowing closing and opening of the prosthesis. The relationship between the motor-driver signal and the actual hand-grasp force developed by the prosthesis was measured using a hand-held grip dynamometer. The resulting force was proportional to current for moderate values of current and then saturated. The motor torque, and, in turn, the force elicited, can be measured by sensing the current absorbed by the motor

  12. Electromyographic analysis of core trunk, hip, and thigh muscles during 9 rehabilitation exercises.

    Science.gov (United States)

    Ekstrom, Richard A; Donatelli, Robert A; Carp, Kenji C

    2007-12-01

    Prospective, single-group, repeated-measures design. To identify exercises that could be used for strength development and the exercises that would be more appropriate for endurance or stabilization training. The exercises analyzed are often used in rehabilitation programs for the spine, hip, and knee. They are active exercises using body weight for resistance; thus a clinician is unable to determine the amount of resistance being applied to a muscle group. Electromyographic (EMG) analysis can provide a measure of muscle activation so that the clinician can have a better idea about the effect the exercise may have on the muscle for strength, endurance, or stabilization. Surface EMG analysis was carried out in 19 males and 11 females while performing the following 9 exercises: active hip abduction, bridge, unilateral-bridge, side-bridge, prone-bridge on the elbows and toes, quadruped arm/lower extremity lift, lateral step-up, standing lunge, and using the Dynamic Edge. The rectus abdominis, external oblique abdominis, longissimus thoracis, lumbar multifidus, gluteus maximus, gluteus medius, vastus medialis obliquus, and hamstring muscles were studied. In healthy subjects, the lateral step-up and the lunge exercises produced EMG levels greater than 45% maximum voluntary isometric contraction (MVIC) in the vastus medialis obliquus, which suggests that they may be beneficial for strengthening that muscle. The side-bridge exercise could be used for strengthening the gluteus medius and the external oblique abdominis muscles, and the quadruped arm/lower extremity lift exercise may help strengthen the gluteus maximus muscle. All the other exercises produced EMG levels less than 45% MVIC, so they may be more beneficial for training endurance or stabilization in healthy subjects. Our results suggest these exercises could be used for a core rehabilitation or performance enhancement program. Depending on the individual needs of a patient or athlete, some of the exercises may

  13. Optimal Elbow Angle for Extracting sEMG Signals During Fatiguing Dynamic Contraction

    Directory of Open Access Journals (Sweden)

    Mohamed R. Al-Mulla

    2015-09-01

    Full Text Available Surface electromyographic (sEMG activity of the biceps muscle was recorded from 13 subjects. Data was recorded while subjects performed dynamic contraction until fatigue and the signals were segmented into two parts (Non-Fatigue and Fatigue. An evolutionary algorithm was used to determine the elbow angles that best separate (using Davies-Bouldin Index, DBI both Non-Fatigue and Fatigue segments of the sEMG signal. Establishing the optimal elbow angle for feature extraction used in the evolutionary process was based on 70% of the conducted sEMG trials. After completing 26 independent evolution runs, the best run containing the optimal elbow angles for separation (Non-Fatigue and Fatigue was selected and then tested on the remaining 30% of the data to measure the classification performance. Testing the performance of the optimal angle was undertaken on nine features extracted from each of the two classes (Non-Fatigue and Fatigue to quantify the performance. Results showed that the optimal elbow angles can be used for fatigue classification, showing 87.90% highest correct classification for one of the features and on average of all eight features (including worst performing features giving 78.45%.

  14. Prosthetic EMG control enhancement through the application of man-machine principles

    Science.gov (United States)

    Simcox, W. A.

    1977-01-01

    An area in medicine that appears suitable to man-machine principles is rehabilitation research, particularly when the motor aspects of the body are involved. If one considers the limb, whether functional or not, as the machine, the brain as the controller and the neuromuscular system as the man-machine interface, the human body is reduced to a man-machine system that can benefit from the principles behind such systems. The area of rehabilitation that this paper deals with is that of an arm amputee and his prosthetic device. Reducing this area to its man-machine basics, the problem becomes one of attaining natural multiaxis prosthetic control using Electromyographic activity (EMG) as the means of communication between man and prothesis. In order to use EMG as the communication channel it must be amplified and processed to yield a high information signal suitable for control. The most common processing scheme employed is termed Mean Value Processing. This technique for extracting the useful EMG signal consists of a differential to single ended conversion to the surface activity followed by a rectification and smoothing.

  15. Atypical hamstrings electromyographic activity as a compensatory mechanism in anterior cruciate ligament deficiency

    NARCIS (Netherlands)

    Boerboom, AL; Hof, AL; Halbertsma, JPK; van Raaij, JJAM; Schenk, W; Diercks, RL; van Horn, [No Value; van Horn, J.R.

    Anterior cruciate ligament (ACL) deficiency may cause functional instability of the knee (noncopers), while other patients compensate and perform at the same level as before injury (copers). This pilot study investigated whether there is a compensatory electromyographic (EMG) activity of the

  16. Sex Comparisons for Relative Peak Torque and Electromyographic Mean Frequency during Fatigue

    Science.gov (United States)

    Stock, Matt S.; Beck, Travis W.; DeFreitas, Jason M.; Ye, Xin

    2013-01-01

    Purpose: This study compared the relative peak torque and normalized electromyographic (EMG) mean frequency (MNF) responses during fatiguing isokinetic muscle actions for men versus women. Method: Twenty men M[subscript age] ± SD = 22 ± 2 years) and 20 women M[subscript age] ± SD = 22 ± 1 years) performed 50 maximal concentric isokinetic muscle…

  17. A preliminary study on electromyographic analysis of the paraspinal musculature in idiopathic scoliosis

    NARCIS (Netherlands)

    Cheung, J.; Halbertsma, J.P.; Veldhuizen, A.G.; Sluiter, W.J.; Maurits, N.M.; Cool, J.C.; van Horn, J.R.

    The paraspinal muscles have been implicated as a major causative factor in the progression of idiopathic scoliosis. Therefore, the objectives of this preliminary study were to measure the electromyographic activity (EMG) of the paraspinal muscles to determine its relationship to progression of the

  18. Influence of Nordic Walking Training on Muscle Strength and the Electromyographic Activity of the Lower Body in Women With Low Bone Mass

    Directory of Open Access Journals (Sweden)

    Ossowski Zbigniew

    2016-06-01

    Full Text Available Introduction. Osteoporosis and osteopenia are related to changes in the quantity and quality of skeletal muscle and contribute to a decreased level of muscle strength. The purpose of this study was to evaluate the impact of Nordic walking training on muscle strength and the electromyographic (EMG activity of the lower body in women with low bone mass. Material and methods. The participants of the study were 27 women with low bone mass. The sample was randomly divided into two groups: a control group and an experimental group. Women from the experimental group participated in 12 weeks of regular Nordic walking training. Functional strength was assessed with a 30-second chair stand test. The EMG activities of the gluteus maximus (GMax, rectus femoris (RF, biceps femoris (BF, soleus (SOL, and lumbar (LB muscles were measured using a surface electromyogram. Results. Nordic walking training induced a significant increase in the functional strength (p = 0.006 of the lower body and activity of GMax (p = 0.013 and a decrease in body mass (p = 0.006 in women with reduced bone mass. There was no statistically significant increase in the EMG activities of the RF, BF, SOL, or LB muscles. The study did not indicate any significant changes in functional muscle strength, the EMG activity of the lower body, or anthropometry in women from the control group. Conclusions. Nordic walking training induces positive changes in lower body strength and the electromyographic activity of the gluteus maximus as well as a decrease in body mass in women with low bone mass.

  19. Study of stability of time-domain features for electromyographic pattern recognition

    Directory of Open Access Journals (Sweden)

    Huang He

    2010-05-01

    Full Text Available Abstract Background Significant progress has been made towards the clinical application of human-machine interfaces (HMIs based on electromyographic (EMG pattern recognition for various rehabilitation purposes. Making this technology practical and available to patients with motor deficits requires overcoming real-world challenges, such as physical and physiological changes, that result in variations in EMG signals and systems that are unreliable for long-term use. In this study, we aimed to address these challenges by (1 investigating the stability of time-domain EMG features during changes in the EMG signals and (2 identifying the feature sets that would provide the most robust EMG pattern recognition. Methods Variations in EMG signals were introduced during physical experiments. We identified three disturbances that commonly affect EMG signals: EMG electrode location shift, variation in muscle contraction effort, and muscle fatigue. The impact of these disturbances on individual features and combined feature sets was quantified by changes in classification performance. The robustness of feature sets was evaluated by a stability index developed in this study. Results Muscle fatigue had the smallest effect on the studied EMG features, while electrode location shift and varying effort level significantly reduced the classification accuracy for most of the features. Under these disturbances, the most stable EMG feature set with combination of four features produced at least 16.0% higher classification accuracy than the least stable set. EMG autoregression coefficients and cepstrum coefficients showed the most robust classification performance of all studied time-domain features. Conclusions Selecting appropriate EMG feature combinations can overcome the impact of the studied disturbances on EMG pattern classification to a certain extent; however, this simple solution is still inadequate. Stabilizing electrode contact locations and developing

  20. ELECTROMYOGRAPHIC STUDY OF A SEQUENCE OF YAU-MAN KUNG FU PALM STRIKES WITH AND WITHOUT IMPACT

    Directory of Open Access Journals (Sweden)

    Osmar Pinto Neto

    2007-10-01

    Full Text Available In martial arts and contact sports, strikes are often trained in two different ways: with and without impacts. This study aims to compare the electromyographical activity (EMG of the triceps brachii (TB, biceps brachii (BB and brachioradialis (BR muscles during strikes with and without impacts. Eight Yau-Man Kung Fu practitioners participated in the experiment. Each participant performed 5 sequences of 5 consecutive KF Yau-Man palm strikes with no impact intercalated with 5 sequences of 5 repetitions targeting a KF training shield. Surface EMG signals were obtained from the TB, BB, and RB for 3.0 seconds using an eight-channel module with a total amplifier gain of 2000 and sampled at 3500 Hz. The EMG analyses were done in the time (rms and frequency (wavelet domains. For the frequency domain, Morlet wavelet power spectra were obtained and an original method was used to quantify statistically significant regions on the power spectra. The results both in the time and frequency domains indicate a higher TB and BR muscle activity for the strikes with impacts. No significant difference was found for the BB in the two different scenarios. In addition, the results show that the wavelet power spectra pattern for the three analysed muscles obtained from the strikes with and without impacts were similar

  1. Activity of the equine rectus abdominis and oblique external abdominal muscles measured by surface EMG during walk and trot on the treadmill.

    Science.gov (United States)

    Zsoldos, R R; Kotschwar, A; Kotschwar, A B; Rodriguez, C P; Peham, C; Licka, T

    2010-11-01

    The rectus abdominis (RA) and oblique external abdominal (OEA) muscles are both part of the construction of the equine trunk and thought to be essential for the function of the spine during locomotion. Although RA activity at trot has previously been investigated, the relationship between OEA and RA at walk and trot has not yet been described. To document abdominal muscle activities during walk and trot, and test the hypothesis that muscle activity at walk would be smaller than at trot. Six horses (8-20 years old, 450-700 kg) were used for surface electromyography (EMG) measurements, with EMG electrodes placed caudal to the sternum (RA) and at the level of the 16th rib (OEA). On all hooves, the withers and the sacrum reflective markers were placed to determine motion cycles. Normal distribution of data was tested using a Kolmogorov-Smirnov test and Student's t test was used to compare left-right and walk-trot differences (P activity ranged from 8-44 mV (RA) and 7-54 mV (OEA). At trot, EMG activity ranged from 18-150 mV (RA) and 27-239 mV (OEA). There were statistically significant differences between maximum activities of left and right OEA and RA muscles at walk in all horses, and in 4/6 horses at trot. Muscle activities of OEA and RA are smaller at walk than at trot. At walk, the OEA/RA ratio is lower than at trot. There are more significant correlations between muscle activities of both RA and OEA and limb movements at walk than at the trot. © 2010 EVJ Ltd.

  2. Advanced biofeedback from surface electromyography signals using fuzzy system

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2010-01-01

    The aims of this study were to develop a fuzzy inference-based biofeedback system and investigate its effects when inducing active (shoulder elevation) and passive (relax) pauses on the trapezius muscle electromyographic (EMG) activity during computer work. Surface EMG signals were recorded from...... clavicular, descending (bilateral) and ascending parts of the trapezius muscles during computer work. The fuzzy system readjusted itself based on the history of previous inputs. The effect of feedback was assessed in terms of muscle activation regularity and amplitude. Active pause resulted in non...

  3. Hip Rotations' Influence of Electromyographic Activity of Gluteus Medius Muscle During Pelvic-Drop Exercise.

    Science.gov (United States)

    Monteiro, Renan Lima; Facchini, Joana Hoverter; de Freitas, Diego Galace; Callegari, Bianca; João, Sílvia Maria Amado

    2017-01-01

    Pelvic-drop exercises are often used to strengthen the gluteus medius (GM) muscle with the aim of increasing or prioritizing its recruitment. However, the effect of hip rotation on the performance of the action of the GM is unknown. To evaluate the effect of hip rotation on the recruitment of the GM, tensor fasciae latae (TFL), and quadratus lumborum (QL). Seventeen healthy subjects performed 2 sets of 4 repetitions of pelvic-drop exercise in random order with pelvic-drop lateral, medial, and neutral rotation of the hip. The electromyographic (EMG) activity of the GM, TFL, and QL was evaluated using surface electromyography. There were significant increases in the activation of the GM with medial and neutral rotation compared with lateral rotation (P = .03, P = .01, respectively), and there was no difference between medial and neutral rotation (P = 1.00). There was no difference in EMG activity of the TFL and QL in any of the positions. The GM:TFL ratio was the same in all analyzed positions. Regarding the GM:QL ratio, there was a significant increase with medial rotation compared with lateral rotation (P = .02). Pelvic-drop exercises are more efficient for activating the GM when the hip is in medial rotation and neutral position.

  4. A Real-Time Pinch-to-Zoom Motion Detection by Means of a Surface EMG-Based Human-Computer Interface

    Directory of Open Access Journals (Sweden)

    Jongin Kim

    2014-12-01

    Full Text Available In this paper, we propose a system for inferring the pinch-to-zoom gesture using surface EMG (Electromyography signals in real time. Pinch-to-zoom, which is a common gesture in smart devices such as an iPhone or an Android phone, is used to control the size of images or web pages according to the distance between the thumb and index finger. To infer the finger motion, we recorded EMG signals obtained from the first dorsal interosseous muscle, which is highly related to the pinch-to-zoom gesture, and used a support vector machine for classification between four finger motion distances. The powers which are estimated by Welch’s method were used as feature vectors. In order to solve the multiclass classification problem, we applied a one-versus-one strategy, since a support vector machine is basically a binary classifier. As a result, our system yields 93.38% classification accuracy averaged over six subjects. The classification accuracy was estimated using 10-fold cross validation. Through our system, we expect to not only develop practical prosthetic devices but to also construct a novel user experience (UX for smart devices.

  5. A real-time pinch-to-zoom motion detection by means of a surface EMG-based human-computer interface.

    Science.gov (United States)

    Kim, Jongin; Cho, Dongrae; Lee, Kwang Jin; Lee, Boreom

    2014-12-29

    In this paper, we propose a system for inferring the pinch-to-zoom gesture using surface EMG (Electromyography) signals in real time. Pinch-to-zoom, which is a common gesture in smart devices such as an iPhone or an Android phone, is used to control the size of images or web pages according to the distance between the thumb and index finger. To infer the finger motion, we recorded EMG signals obtained from the first dorsal interosseous muscle, which is highly related to the pinch-to-zoom gesture, and used a support vector machine for classification between four finger motion distances. The powers which are estimated by Welch's method were used as feature vectors. In order to solve the multiclass classification problem, we applied a one-versus-one strategy, since a support vector machine is basically a binary classifier. As a result, our system yields 93.38% classification accuracy averaged over six subjects. The classification accuracy was estimated using 10-fold cross validation. Through our system, we expect to not only develop practical prosthetic devices but to also construct a novel user experience (UX) for smart devices.

  6. Dynamic factors and electromyographic activity in a sprint start

    Directory of Open Access Journals (Sweden)

    M Čoh

    2009-07-01

    Full Text Available The aim of the study was to establish the major dynamic parameters as well as the EMG activation of muscles in a sprint start as the first derivative of sprint velocity. The subject of the analysis was block velocity, the production of force in the front and rear starting blocks, the block acceleration in the first two steps and the electromyographic activity (EMG of the following muscles: the erector spinae muscle, gluteus maximus muscle, rectus femoris muscle, vastus medialis muscle, vastus lateralis muscle, biceps femoris muscle and gastrocnemius–medialis muscle. One international-class female sprinter participated in the experiment. She performed eight starts in constant laboratory conditions. The 3-D kinematic analysis was made using a system of nine Smart-e 600 cameras operating at a frame rate of 60 Hz. Dynamic parameters were established by means of two separate force platforms to which the starting blocks were fixed. A 16-channel electromyograph was used to analyse electromyographic activity (EMG. It was established that the block velocity depended on the absolute force produced in the front and rear starting blocks and that it was 2.84±0.21 m.s-1. The maximal force on the rear and front blocks was 628±34 N and 1023±30 N, respectively. In view of the total impulse (210±11 Ns the force production/time ratio in the rear and front blocks was 34%:66%. The erector spinae muscle, vastus lateralis muscle and gastrocnemius–medialis muscle generate the efficiency of the start. The block acceleration in the first two steps primarily depends on the activation of the gluteus maximus muscle, rectus femoris muscle, biceps femoris muscle and gastrocnemius–medialis muscle. A sprint start is a complex motor stereotype requiring a high degree of integration of the processes of central movement regulation and an optimal level of biomotor abilities.

  7. Electromyographic and ultrasonographic evaluation of the masseter muscle individuals with unilateral peripheral facial paralysis

    Directory of Open Access Journals (Sweden)

    Sassi, Fernanda Chiarion

    2011-10-01

    Full Text Available Introduction: Individuals with peripheral Facial Paralysis (FP show conditions that lead to unilateral mastication, performed by the non-affected side, mainly due to the difficulty of action of the buccinator muscle. Objectives: characterize the motor control and morphology of the masseter muscle in individuals with unilateral peripheral FP through electromyographic and ultrasonographic evaluation. Method: 16 participants, of both sexes, with ages superior to 18 years old. The study group (SG consisted of 8 individuals who'd had idiopathic unilateral peripheral FP for more than 6 months; the control group (CG consisted of 8 normal individuals. All the subjects were submitted to the masseter muscle evaluation through surface electromyography (sEMG and ultrasonography (USG during the following tasks: rest, clenching with cotton roller between the teeth (CT and clenching with maximum intercuspation (MIC. Results: There was no statistically significant difference in comparisons within and between the groups concerning the hemifacial asymmetry, both for the sEMG and for the USG. Also there were no significant differences in the activation of the masticatory muscles (masseter and temporal in the sEMG. Conclusions: Both the motor control and the morphology of the masseter muscles in individuals with unilateral peripheral FP were similar to those of normal individuals. Although literature suggests that the demand of functional adaptations made by FP individuals could exceed the structural and functional tolerance of the temporomandibular joints, the results indicate that the length of analyzed patient's FP was not enough to generate anatomical and physiological differences in the masticatory muscles.

  8. Automated analysis of prerecorded evoked electromyographic activity from rat muscle.

    Science.gov (United States)

    Basarab-Horwath, I; Dewhurst, D G; Dixon, R; Meehan, A S; Odusanya, S

    1989-03-01

    An automated microprocessor-based data acquisition and analysis system has been developed specifically to quantify electromyographic (EMG) activity induced by the convulsant agent catechol in the anaesthetized rat. The stimulus and EMG response are recorded on magnetic tape. On playback, the stimulus triggers a digital oscilloscope and, via interface circuitry, a BBC B microcomputer. The myoelectric activity is digitized by the oscilloscope before being transferred under computer control via a RS232 link to the microcomputer. This system overcomes the problems of dealing with signals of variable latency and allows quantification of latency, amplitude, area and frequency of occurrence of specific components within the signal. The captured data can be used to generate either signal or superimposed high resolution graphic reproductions of the original waveforms. Although this system has been designed for a specific application, it could easily be modified to allow analysis of any complex waveform.

  9. Transvaginal electrical stimulation with surface-EMG biofeedback in managing stress urinary incontinence in women of premenopausal age: a double-blind, placebo-controlled, randomized clinical trial.

    Science.gov (United States)

    Terlikowski, Robert; Dobrzycka, Bozena; Kinalski, Maciej; Kuryliszyn-Moskal, Anna; Terlikowski, Slawomir J

    2013-10-01

    The aim of this study was to evaluate the results of conservative treatment of urodynamic stress urinary incontinence (SUI) using transvaginal electrical stimulation with surface-electromyography-assisted biofeedback (TVES + sEMG) in women of premenopausal age. One hundred and two patients with SUI were divided into two groups: active (n = 68) and placebo (n = 34) TVES + sEMG. The treatment lasted for 8 weeks and consisted of two sessions per day. Women were evaluated before and after the intervention by pad test, voiding diary, urodynamic test, and the Incontinence Quality of Life Questionnaire (I-QOL). Mean urinary leakage on a standard pad test at the end of 8th week was significantly lower in the active than the placebo group (19.5 ± 13.6 vs. 39.8 ± 28.5). Mean urinary leakage on a 24-h pad test was significantly reduced in the active group at the end of 8th and 16th weeks compared with the placebo group (8.2 ± 14.8 vs. 14.6 ± 18.9 and 6.1 ± 11.4 vs. 18.2 ± 20.8, respectively). There was also a significant improvement in muscle strength as measured by the Oxford scale in the active vs the placebo group after 8 and 16 weeks (4.2 vs 2.6 and 4.1 vs 2.7, respectively). No significant difference was found between groups in urodynamic data before and after treatment. At the end of 8th week, the mean I-QOL score in the active vs the placebo group was 78.2 ± 17.9 vs 55.9 ± 14.2, respectively, and at the end of 16th week 80.8 ± 24.1 vs. 50.6 ± 14.9, respectively. Our study showed that TVES + sEMG is a trustworthy method of treatment in premenopausal women with SUI; however, its reliability needs to be established.

  10. Muscle fiber velocity and electromyographic signs of fatigue in fibromyalgia

    NARCIS (Netherlands)

    Klaver-Krol, E.G.; Rasker, J.J.; Henriquez, N.R.; Verheijen, W.G.; Zwarts, M.J.

    2012-01-01

    INTRODUCTION: Fibromyalgia (FM) is a disorder of widespread muscular pain. We investigated possible differences in surface electromyography (sEMG) in clinically unaffected muscle between patients with FM and controls. METHODS: sEMG was performed on the biceps brachii muscle of 13 women with FM and

  11. Muscle fiber velocity and electromyographic signs of fatigue in fibromyalgia

    NARCIS (Netherlands)

    Klaver-Krol, E.G.; Rasker, Johannes J.; Henriquez, N.R.; Verheijen, W.G.; Zwarts, M.J.

    2012-01-01

    Introduction: Fibromyalgia (FM) is a disorder of widespread muscular pain. We investigated possible differences in surface electromyography (sEMG) in clinically unaffected muscle between patients with FM and controls. Methods: sEMG was performed on the biceps brachii muscle of 13 women with FM and

  12. Surface electromyography physiology, engineering and applications

    CERN Document Server

    Farina, Dario

    2016-01-01

    The book presents a quantitative approach to the study and use of noninvasively detected electromyographic (EMG) signals, as well as their numerous applications in various aspects of the life sciences. Surface Electromyography: Physiology, Engineering, and Applications is an update of Electromyography: Physiology, Engineering, and Noninvasive Applications (Wiley-IEEE Press, 2004) and focuses on the developments that have taken place over the last decade. The first nine chapters deal with the generation, detection, understanding, interpretation, and modeling of EMG signals. Detection technology, with particular focus on EMG imaging techniques that are based on two-dimensional electrode arrays are also included in the first half of the book. The latter 11 chapters deal with applications, which range fro monitoring muscle fatigue, electrically elicited contractions, posture analysis, prevention of work-related and child-delivery-related neuromuscular disorders, ergonomics, movement analysis, physical therapy, ex...

  13. Effect of Selective Muscle Training Using Visual EMG Biofeedback on Infraspinatus and Posterior Deltoid

    OpenAIRE

    Lim, One-bin; Kim, Jeong-ah; Song, Si-jeong; Cynn, Heon-seock; Yi, Chung-hwi

    2014-01-01

    We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The v...

  14. Kinesiology Taping does not Modify Electromyographic Activity or Muscle Flexibility of Quadriceps Femoris Muscle: A Randomized, Placebo-Controlled Pilot Study in Healthy Volleyball Players.

    Science.gov (United States)

    Halski, Tomasz; Dymarek, Robert; Ptaszkowski, Kuba; Słupska, Lucyna; Rajfur, Katarzyna; Rajfur, Joanna; Pasternok, Małgorzata; Smykla, Agnieszka; Taradaj, Jakub

    2015-08-01

    Kinesiology taping (KT) is a popular method of supporting professional athletes during sports activities, traumatic injury prevention, and physiotherapeutic procedures after a wide range of musculoskeletal injuries. The effectiveness of KT in muscle strength and motor units recruitment is still uncertain. The objective of this study was to assess the effect of KT on surface electromyographic (sEMG) activity and muscle flexibility of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles in healthy volleyball players. Twenty-two healthy volleyball players (8 men and 14 women) were included in the study and randomly assigned to 2 comparative groups: "kinesiology taping" (KT; n=12; age: 22.30 ± 1.88 years; BMI: 22.19 ± 4.00 kg/m(2)) in which KT application over the RF muscle was used, and "placebo taping" (PT; n=10; age: 21.50 ± 2.07 years; BMI: 22.74 ± 2.67 kg/m(2)) in which adhesive nonelastic tape over the same muscle was used. All subjects were analyzed for resting sEMG activity of the VL and VM muscles, resting and functional sEMG activity of RF muscle, and muscle flexibility of RF muscle. No significant differences in muscle flexibility of the RF muscle and sEMG activity of the RF, VL, and VM muscles were registered before and after interventions in both groups, and between the KT and PT groups (p>0.05). The results show that application of the KT to the RF muscle is not useful to improve sEMG activity.

  15. Postural and dynamic masseter and anterior temporalis muscle EMG repeatability in serial assessments.

    Science.gov (United States)

    Suvinen, T I; Malmberg, J; Forster, C; Kemppainen, P

    2009-11-01

    Electromyographic (EMG) assessment has been used as a non-invasive tool to objectively assess muscle function, although with controversial research and clinical potential. The aim of this study was to assess within-, inter-subject and between-day repeatability of serial EMG recordings. The study sample included 10 asymptomatic subjects with no history of temporomandibular disorders or muscle parafunctions. Bilateral masseter and anterior temporalis muscle EMG parameters were assessed in two standardized serial recordings (day 1 to day 2) using a portable EMG equipment (ME 6000 recorder, Mega Electronics, Kuopio, Finland). The functional tasks included postural/resting activities as pre- and post-recording series of 30 s each and jaw opening/closing, intercuspal and maximal voluntary clenching activities of 5 s, repeated three times. The assessed EMG parameters included the mean amplitude, s.d. and error. In addition, the power spectrum EMG parameter assessment included the median power frequencies and the averaged EMG spectrum data values. The results of the intraclass correlation coefficient analysis indicated reliability for nearly all of the intercuspal and all clenching EMG amplitude and power spectrum parameters. This was complemented by the repeated measures anova and post hoc analyses that indicated non-significant differences between day 1 and 2 in task- and muscle-related analyses. Most variability was noted in postural and some in opening/closing tasks. In conclusion this study assessed the reliability, repeatability and limitations of postural and various dynamic masseter and temporalis EMG recordings for serial assessment.

  16. An electromyographic exploratory study comparing the difference in the onset of hamstring and quadriceps contraction in patients with anterior knee pain.

    Science.gov (United States)

    Patil, Sunit; Dixon, John; White, Lisa C; Jones, Alex P; Hui, Anthony C W

    2011-10-01

    Idiopathic anterior knee pain in teenagers and young adults is a common condition. Patellar maltracking has been considered as a causative factor. The aim of our study was to investigate whether there was a difference in the timing of electromyographic (EMG) activity in the medial and lateral hamstring and quadriceps muscles of patients with anterior knee pain compared to asymptomatic control participants. This was a cross sectional observational study measuring EMG activation patterns. Two groups of participants were tested, one patient (mean age 15 years, n = 20) and one asymptomatic control (mean age 16 years, n = 17). Surface EMG (sampling rate 1000 Hz) was recorded from vastus medialis obliqus, vastus lateralis, and the medial and lateral hamstrings during three repetitions of maximal voluntary isometric contractions. The relative timing of the medial and lateral quadriceps and hamstrings was evaluated. The mean (95% confidence interval) difference between the groups in the lateral-medial hamstring onset timing was 53.8(1.9 to 105.6)ms during the maximal contraction. An independent t test showed that this difference was statistically significant (p = 0.043). The differences between the groups in the relative VMO to VL onset did not reach statistical significance. The results of this study suggest that the lateral hamstrings contract significantly earlier in patients with AKP compared to healthy controls for this small cohort. This altered activation pattern could produce external rotation of the tibia on the femur and cause lateral patella tracking. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. A Comparison of Gluteus Maximus, Biceps Femoris, and Vastus Lateralis Electromyographic Activity in the Back Squat and Barbell Hip Thrust Exercises.

    Science.gov (United States)

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2015-12-01

    The back squat and barbell hip thrust are both popular exercises used to target the lower body musculature; however, these exercises have yet to be compared. Therefore, the purpose of this study was to compare the surface electromyographic (EMG) activity of the upper and lower gluteus maximus, biceps femoris, and vastus lateralis between the back squat and barbell hip thrust. Thirteen trained women (n = 13; age = 28.9 years; height = 164 cm; mass = 58.2 kg) performed estimated 10-repetition maximums (RM) in the back squat and barbell hip thrust. The barbell hip thrust elicited significantly greater mean (69.5% vs 29.4%) and peak (172% vs 84.9%) upper gluteus maximus, mean (86.8% vs 45.4%) and peak (216% vs 130%) lower gluteus maximus, and mean (40.8% vs 14.9%) and peak (86.9% vs 37.5%) biceps femoris EMG activity than the back squat. There were no significant differences in mean (99.5% vs 110%) or peak (216% vs 244%) vastus lateralis EMG activity. The barbell hip thrust activates the gluteus maximus and biceps femoris to a greater degree than the back squat when using estimated 10RM loads. Longitudinal training studies are needed to determine if this enhanced activation correlates with increased strength, hypertrophy, and performance.

  18. Comparison of electromyographic activity during the bench press and barbell pulloverexercises

    Directory of Open Access Journals (Sweden)

    Yuri de Almeida Costa Campos

    2014-06-01

    Full Text Available The aim of the study was to compare the electromyographic (EMG activity of the following muscles: clavicular portion of pectoralis major, sternal portion of pectoralis major, long portion of triceps brachii, anterior deltoid, posterior deltoid and latissimus dorsi during dynamic contractions between flat horizontal bench press and barbell pulloverexercises. The sample comprised 12 males individuals experienced in resistance training. The volunteers made three visits to the laboratory. The first one consisted of 12 repetitions of the exercises for the electromyographic data collection. The results showed a higher EMG activation of the pectoralis major and anterior deltoid muscles in the flat horizontal bench press in comparison with the barbell pullover. The triceps brachii and latissimus dorsi muscles were more activated in the barbell pullover.

  19. Comparison of electromyographic activity during the bench press and barbell pulloverexercises

    OpenAIRE

    Campos,Yuri de Almeida Costa; Silva,Sandro Fernandes da

    2014-01-01

    The aim of the study was to compare the electromyographic (EMG) activity of the following muscles: clavicular portion of pectoralis major, sternal portion of pectoralis major, long portion of triceps brachii, anterior deltoid, posterior deltoid and latissimus dorsi during dynamic contractions between flat horizontal bench press and barbell pulloverexercises. The sample comprised 12 males individuals experienced in resistance training. The volunteers made three visits to the laboratory. The fi...

  20. Electromyographic activity imbalances between contralateral back muscles: An assessment of measurement properties.

    Science.gov (United States)

    Larivière, Christian; Gagnon, Denis; Arsenault, A Bertrand; Gravel, Denis; Loisel, Patrick

    2005-01-01

    Electromyographic (EMG) contralateral imbalances of back muscles are often interpreted as an aberrant back muscle pattern related to back pain. This study assessed different measurement properties (influence of the control of asymmetric efforts and of the force level, reliability, and sensitivity to low back status) of EMG imbalance parameters. Healthy controls (n = 34) and chronic low back pain subjects (n = 55) stood in a dynamometer measuring the principal (extension) and coupled (lateral bending, axial rotation) L5/S1 moments during isometric trunk extension efforts. The results showed that back pain subjects did not produce higher coupled moments than controls. Providing feedback of the axial rotation moment to correct asymmetric efforts during the task did not reduce EMG contralateral imbalances, except for some extreme cases. Normalized EMG imbalance parameters remain relatively constant between 40% and 80% of the maximal voluntary contraction. The reliability of EMG imbalance parameters was moderate, at best. Finally, neither low back status nor pain location had an effect on EMG contralateral imbalances. We conclude that the clinical relevance of EMG contralateral imbalances of back muscles remains to be established.

  1. Effect of neurofeedback and electromyographic-biofeedback therapy on improving hand function in stroke patients.

    Science.gov (United States)

    Rayegani, S M; Raeissadat, S A; Sedighipour, L; Rezazadeh, I Mohammad; Bahrami, M H; Eliaspour, D; Khosrawi, S

    2014-01-01

    The aim of the present study was to evaluate the effect of applying electroencephalogram (EEG) biofeedback (neurobiofeedback) or electromyographic (EMG) biofeedback to conventional occupational therapy (OT) on improving hand function in stroke patients. This study was designed as a preliminary clinical trial. Thirty patients with stroke were entered the study. Hand function was evaluated by Jebsen Hand Function Test pre and post intervention. Patients were allocated to 3 intervention cohorts: (1) OT, (2) OT plus EMG-biofeedback therapy, and (3) OT plus neurofeedback therapy. All patients received 10 sessions of conventional OT. Patients in cohorts 2 and 3 also received EMG-biofeedback and neurofeedback therapy, respectively. EMG-biofeedback therapy was performed to strengthen the abductor pollicis brevis (APB) muscle. Neurofeedback training was aimed at enhancing sensorimotor rhythm after mental motor imagery. Hand function was improved significantly in the 3 groups. The spectral power density of the sensorimotor rhythm band in the neurofeedback group increased after mental motor imagery. Maximum and mean contraction values of electrical activities of the APB muscle during voluntary contraction increased significantly after EMG-biofeedback training. Patients in the neurofeedback and EMG-biofeedback groups showed hand improvement similar to conventional OT. Further studies are suggested to assign the best protocol for neurofeedback and EMG-biofeedback therapy.

  2. An EMG Interface for the Control of Motion and Compliance of a Supernumerary Robotic Finger

    Science.gov (United States)

    Hussain, Irfan; Spagnoletti, Giovanni; Salvietti, Gionata; Prattichizzo, Domenico

    2016-01-01

    In this paper, we propose a novel electromyographic (EMG) control interface to control motion and joints compliance of a supernumerary robotic finger. The supernumerary robotic fingers are a recently introduced class of wearable robotics that provides users additional robotic limbs in order to compensate or augment the existing abilities of natural limbs without substituting them. Since supernumerary robotic fingers are supposed to closely interact and perform actions in synergy with the human limbs, the control principles of extra finger should have similar behavior as human’s ones including the ability of regulating the compliance. So that, it is important to propose a control interface and to consider the actuators and sensing capabilities of the robotic extra finger compatible to implement stiffness regulation control techniques. We propose EMG interface and a control approach to regulate the compliance of the device through servo actuators. In particular, we use a commercial EMG armband for gesture recognition to be associated with the motion control of the robotic device and surface one channel EMG electrodes interface to regulate the compliance of the robotic device. We also present an updated version of a robotic extra finger where the adduction/abduction motion is realized through ball bearing and spur gears mechanism. We have validated the proposed interface with two sets of experiments related to compensation and augmentation. In the first set of experiments, different bimanual tasks have been performed with the help of the robotic device and simulating a paretic hand since this novel wearable system can be used to compensate the missing grasping abilities in chronic stroke patients. In the second set, the robotic extra finger is used to enlarge the workspace and manipulation capability of healthy hands. In both sets, the same EMG control interface has been used. The obtained results demonstrate that the proposed control interface is intuitive and can

  3. Quantitative electromyographic examination in myogenic disorders of 6 horses.

    Science.gov (United States)

    Wijnberg, I D; Franssen, H; Jansen, G H; Back, W; van der Kolk, J H

    2003-01-01

    Electromyographic needle examination (EMG), including the semiautomatic quantitative analysis of motor unit action potential (MUAP), is an important diagnostic tool for myopathy in humans. The diagnostic possibilities of this technique have not been fully explored in horses; however, recent studies have shown that MUAP analysis can be performed in conscious horses. To determine the diagnostic possibilities of EMG in horses, we compared the EMG results of the subclavian muscle, the triceps, and the lateral vastus muscle in 6 equine patients thought to have myogenic disorders with those in 7 normal control horses. The EMG results were compared with the results of the histopathologic examination of the lateral vastus muscle in patients and controls. Histopathologic examination showed muscle disease in 3 patients. In the patient group, several types of abnormal spontaneous activities were observed (mainly fibrillation potentials and positive sharp waves), and the MUAPs of the patient group had a markedly shorter duration and lower amplitude than those of the control group. In the subclavian muscle, triceps, and lateral vastus muscle of affected horses, the MUAP duration was 5.0 +/- 0.4 (mean +/- SD), 3.9 +/- 0.3, and 4.7 +/- 1.1 milliseconds, respectively. The MUAP amplitude was 217 +/- 55, 150 +/- 74, and 180 +/- 54 microV; the number of phases was 2.4 +/- 0.2, 2.5 +/- 0.3, and 2.3 +/- 0.1; and the number of turns was 2.6 +/- 0.2, 2.4 +/- 0.2, and 2.8 +/- 0.5, respectively. In conclusion, it appears that the EMG may be a more sensitive method than other techniques for examining muscle biopsies for diagnosis of early-stage myopathy in horses.

  4. Comparison of methods for removing electromagnetic noise from electromyographic signals

    International Nuclear Information System (INIS)

    DeFreitas, Jason M; Beck, Travis W; Stock, Matt S

    2012-01-01

    The purpose of this investigation was to compare three different methods of removing noise from monopolar electromyographic (EMG) signals: (a) electrical shielding with a Faraday cage, (b) denoising with a digital notch-filter and (c) applying a bipolar differentiation with another monopolar EMG signal. Ten men and ten women (mean age = 24.0 years) performed isometric muscle actions of the leg extensors at 10–100% of their maximal voluntary contraction on two separate occasions. One trial was performed inside a Faraday tent (a flexible Faraday cage made from conductive material), and the other was performed outside the Faraday tent. The EMG signals collected outside the Faraday tent were analyzed three separate ways: as a raw signal, as a bipolar signal, and as a signal digitally notch filtered to remove 60 Hz noise and its harmonics. The signal-to-noise ratios were greatest after notch-filtering (range: 3.0–33.8), and lowest for the bipolar arrangement (1.6–10.2). Linear slope coefficients for the EMG amplitude versus force relationship were also used to compare the methods of noise removal. The results showed that a bipolar arrangement had a significantly lower linear slope coefficient when compared to the three other conditions (raw, notch and tent). These results suggested that an appropriately filtered monopolar EMG signal can be useful in situations that require a large pick-up area. Furthermore, although it is helpful, a Faraday tent (or cage) is not required to achieve an appropriate signal-to-noise ratio, as long as the correct filters are applied. (paper)

  5. Surface electromyographic evaluation of jaw muscles in children with unilateral crossbite and lateral shift in the early mixed dentition. Sexual dimorphism.

    Science.gov (United States)

    Lenguas, Leticia; Alarcón, José-Antonio; Venancio, Filipa; Kassem, Marta; Martín, Conchita

    2012-11-01

    To examine the activity of jaw muscles at rest and during maximal voluntary clenching (MVC) in children with unilateral posterior crossbite (UPXB) and functional lateral shift in the early mixed dentition and to evaluate sex differences. The sample included 30 children (15 males, 15 females) aged 6 to 10 years old, with UPXB and functional mandibular lateral shift (≥1.5 mm) in the early mixed dentition. sEMG activity coming from the muscle areas (anterior temporalis [AT], posterior temporalis [PT], masseter [MA] and suprahyoid [SH]) were obtained from both the crossbite (XB) and noncrossbite (NONXB) sides at mandibular rest position. sEMG activity of the bilateral AT and MA muscles sides was obtained during MVC. Asymmetry and activity indexes were calculated for each muscle area at rest and during MVC; the MA/TA ratio during MVC was also determined. At rest, no differences were found between sexes for any muscle areas or asymmetry and activity indexes. No differences were found between XB and NONXB sides. During MVC, however, significant sex differences were found in AT and MA activity, with higher sEMG values in males than in females, on both XB and NONXB sides. Asymmetry indexes, activity indexes and MA/AT ratios did not show significant differences between the sexes. Activity was symmetric both in males and in females. At rest, no sex differences were found, but during MVC males showed higher activity than did females in both XB and NONXB AT and MA muscle areas. Muscular activity was symmetrical at rest and during MVC in both sexes. Sexual dimorphism should be considered in the diagnosis and treatment of UPXB and lateral shift in the early mixed dentition.

  6. EMG evaluation of hip adduction exercises for soccer players

    DEFF Research Database (Denmark)

    Serner, Andreas; Jakobsen, Markus Due; Andersen, Lars Louis

    2014-01-01

    traditional and two new hip adduction exercises. Additionally, to analyse muscle activation of gluteals and abdominals. MATERIALS AND METHODS: 40 healthy male elite soccer players, training >5 h a week, participated in the study. Muscle activity using surface electromyography (sEMG) was measured bilaterally...... for the adductor longus during eight hip adduction strengthening exercises and peak EMG was normalised (nEMG) using an isometric maximal voluntary contraction (MVC) as reference. Furthermore, muscle activation of the gluteus medius, rectus abdominis and the external abdominal obliques was analysed during...... the exercises. RESULTS: There were large differences in peak nEMG of the adductor longus between the exercises, with values ranging from 14% to 108% nEMG (pEMG results for the gluteals...

  7. Locomotor changes in length and EMG activity of feline medial gastrocnemius muscle following paralysis of two synergists

    NARCIS (Netherlands)

    Maas, H.; Gregor, R.J.; Hodson-Tole, E.F.; Farrell, B.J.; English, A.W.; Prilutsky, B.I.

    2010-01-01

    The mechanism of the compensatory increase in electromyographic activity (EMG) of a cat ankle extensor during walking shortly after paralysis of its synergists is not fully understood. It is possible that due to greater ankle Xexion in stance in this situation, muscle spindles are stretched to a

  8. Drop punt kicking induces eccentric knee flexor weakness associated with reductions in hamstring electromyographic activity.

    Science.gov (United States)

    Duhig, Steven J; Williams, Morgan D; Minett, Geoffrey M; Opar, David; Shield, Anthony J

    2017-06-01

    To examine the effect of 100 drop punt kicks on isokinetic knee flexor strength and surface electromyographic activity of bicep femoris and medial hamstrings. Randomized control study. Thirty-six recreational footballers were randomly assigned to kicking or control groups. Dynamometry was conducted immediately before and after the kicking or 10min of sitting (control). Eccentric strength declined more in the kicking than the control group (phamstring surface electromyographic activity (bicep femoris and medial hamstrings combined) was greater in the kicking than the control group (phamstring surface electromyographic activity did not differ between groups (p=0.863; d=0.04). Post-kicking reductions in surface electromyographic activity were greater in eccentric than concentric actions for both bicep femoris (p=0.008; d=0.77) and medial hamstrings (phamstring surface electromyographic activity for bicep femoris (p=0.026; d=0.64) and medial hamstrings (p=0.032; d=0.53). Reductions in bicep femoris surface electromyographic activity were correlated with eccentric strength decline (R=0.645; p=0.007). Reductions in knee flexor strength and hamstring surface electromyographic activity are largely limited to eccentric contractions and this should be considered when planning training loads in Australian Football. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  9. Navigating features: a topologically informed chart of electromyographic features space.

    Science.gov (United States)

    Phinyomark, Angkoon; Khushaba, Rami N; Ibáñez-Marcelo, Esther; Patania, Alice; Scheme, Erik; Petri, Giovanni

    2017-12-01

    The success of biological signal pattern recognition depends crucially on the selection of relevant features. Across signal and imaging modalities, a large number of features have been proposed, leading to feature redundancy and the need for optimal feature set identification. A further complication is that, due to the inherent biological variability, even the same classification problem on different datasets can display variations in the respective optimal sets, casting doubts on the generalizability of relevant features. Here, we approach this problem by leveraging topological tools to create charts of features spaces. These charts highlight feature sub-groups that encode similar information (and their respective similarities) allowing for a principled and interpretable choice of features for classification and analysis. Using multiple electromyographic (EMG) datasets as a case study, we use this feature chart to identify functional groups among 58 state-of-the-art EMG features, and to show that they generalize across three different forearm EMG datasets obtained from able-bodied subjects during hand and finger contractions. We find that these groups describe meaningful non-redundant information, succinctly recapitulating information about different regions of feature space. We then recommend representative features from each group based on maximum class separability, robustness and minimum complexity. © 2017 The Authors.

  10. An open and configurable embedded system for EMG pattern recognition implementation for artificial arms.

    Science.gov (United States)

    Jun Liu; Fan Zhang; Huang, He Helen

    2014-01-01

    Pattern recognition (PR) based on electromyographic (EMG) signals has been developed for multifunctional artificial arms for decades. However, assessment of EMG PR control for daily prosthesis use is still limited. One of the major barriers is the lack of a portable and configurable embedded system to implement the EMG PR control. This paper aimed to design an open and configurable embedded system for EMG PR implementation so that researchers can easily modify and optimize the control algorithms upon our designed platform and test the EMG PR control outside of the lab environments. The open platform was built on an open source embedded Linux Operating System running a high-performance Gumstix board. Both the hardware and software system framework were openly designed. The system was highly flexible in terms of number of inputs/outputs and calibration interfaces used. Such flexibility enabled easy integration of our embedded system with different types of commercialized or prototypic artificial arms. Thus far, our system was portable for take-home use. Additionally, compared with previously reported embedded systems for EMG PR implementation, our system demonstrated improved processing efficiency and high system precision. Our long-term goals are (1) to develop a wearable and practical EMG PR-based control for multifunctional artificial arms, and (2) to quantify the benefits of EMG PR-based control over conventional myoelectric prosthesis control in a home setting.

  11. Effect of a pelvic belt on EMG activity during manual load lifting

    Directory of Open Access Journals (Sweden)

    Marcelo Pinto Pereira

    2009-04-01

    Full Text Available Manual lifting (ML capacity is still a matter of concern for industry administrators and electromyography (EMG seems to be a good alternative for the evaluation of muscles involved in this task. However, the reliability of these measures is very important. Thus, the objective of this study was to evaluate the influence of a pelvic belt on EMG activity of the erector spinus (ES and rectus femoralis (RF muscles during ML and during maximal voluntary contractions (MVC of trunk extension performed before (baseline and after ML. In addition, the variabilityin the EMG signal normalized by the following three different methods was evaluated: peak EMG activity, mean EMG activity, and EMG activity obtained during MVC. Eight volunteers performed ML of 15% and 25% of their body weight for 1 minute in the presence or absence of a pelvic belt. The coefficient of variation (CV of the EMG signal obtained for the ES and RF muscles was calculated during ML. Load cell traction values and the electromyographic variables RMS, median frequency, mean power frequency and total power of the ES muscle were obtained during MVC. The results showed lower CV (smaller variability when the EMG signal was normalized by peak activity, with this method thus being preferable. During MVC, only the load cell traction value differed from baseline after ML of 25% body weight without the pelvic belt (p=0.035, a finding suggesting rapid recovery of ES muscle after ML for 1 minute.

  12. EMG signal morphology in essential tremor and Parkinson's disease.

    Science.gov (United States)

    Ruonala, V; Meigal, A; Rissanen, S M; Airaksinen, O; Kankaanpaa, M; Karjalainen, P A

    2013-01-01

    The aim of this work was to differentiate patients with essential tremor from patients with Parkinson's disease. The electromyographic signal from the biceps brachii muscle was measured during isometric tension from 17 patients with essential tremor, 35 patients with Parkinson's disease, and 40 healthy controls. The EMG signals were high pass filtered and divided to smaller segments from which histograms were calculated using 200 histogram bins. EMG signal histogram shape was analysed with a feature dimension reduction method, the principal component analysis, and the shape parameters were used to differentiate between different patient groups. The height of the histogram and the side difference between left and right hand were the best discriminators between essential tremor and Parkinson's disease groups. With this method, it was possible to discriminate 13/17 patients with essential tremor from 26/35 patients with Parkinson's disease and 14/17 patients with essential tremor from 29/40 healthy controls.

  13. Sequential decoding of intramuscular EMG signals via estimation of a Markov model.

    Science.gov (United States)

    Monsifrot, Jonathan; Le Carpentier, Eric; Aoustin, Yannick; Farina, Dario

    2014-09-01

    This paper addresses the sequential decoding of intramuscular single-channel electromyographic (EMG) signals to extract the activity of individual motor neurons. A hidden Markov model is derived from the physiological generation of the EMG signal. The EMG signal is described as a sum of several action potentials (wavelet) trains, embedded in noise. For each train, the time interval between wavelets is modeled by a process that parameters are linked to the muscular activity. The parameters of this process are estimated sequentially by a Bayes filter, along with the firing instants. The method was tested on some simulated signals and an experimental one, from which the rates of detection and classification of action potentials were above 95% with respect to the reference decomposition. The method works sequentially in time, and is the first to address the problem of intramuscular EMG decomposition online. It has potential applications for man-machine interfacing based on motor neuron activities.

  14. Electromyographic, cerebral and muscle hemodynamic responses during intermittent, isometric contractions of the biceps brachii at three submaximal intensities

    Directory of Open Access Journals (Sweden)

    Yagesh eBhambhani

    2014-06-01

    Full Text Available This study examined the electromyographic, cerebral and muscle hemodynamic responses during intermittent isometric contractions of biceps brachii at 20%, 40% and 60% of maximal voluntary contraction (MVC. Eleven volunteers completed two minutes of intermittent isometric contractions (12/min at an elbow angle of 90° interspersed with three minutes rest between intensities in systematic order. Surface electromyography (EMG was recorded from the right biceps brachii and near infrared spectroscopy (NIRS was used to simultaneously measure left prefrontal and right biceps brachii oxyhemoglobin (HbO2, deoxyhemoglobin (HHb and total hemoglobin (Hbtot. Transcranial Doppler ultrasound was used to measure middle cerebral artery velocity (MCAv bilaterally. Finger photoplethysmography was used to record beat-to-beat blood pressure and heart rate. EMG increased with force output from 20% to 60% MVC (P0.05. MCAv increased from rest to exercise but was not different among intensities (P>0.05. Force output correlated with the root mean square EMG and changes in muscle HbO2 (P0.05 at all three intensities. Force output declined by 8% from the 1st to the 24th contraction only at 60% MVC and was accompanied by systematic increases in RMS, cerebral HbO2 and Hbtot with a levelling off in muscle HbO2 and Hbtot. These changes were independent of alterations in mean arterial pressure. Since cerebral blood flow and oxygenation were elevated at 60% MVC, we attribute the development of fatigue to reduced muscle oxygen availability rather than impaired central n

  15. Electromyographic activity after latissimus dorsi transfer: testing of coactivation as a simple tool to assess latissimus dorsi motor learning.

    Science.gov (United States)

    Plath, Johannes E; Seiberl, Wolfgang; Beitzel, Knut; Minzlaff, Philipp; Schwirtz, Ansgar; Imhoff, Andreas B; Buchmann, Stefan

    2014-08-01

    The purpose of this study was to investigate coactivation (CoA) testing as a clinical tool to monitor motor learning after latissimus dorsi tendon transfer. We evaluated 20 patients clinically with the American Shoulder and Elbow Surgeons (ASES) and University of California-Los Angeles (UCLA) outcomes scores, visual analog scale, active external rotation (aER), and isometric strength testing in abduction and external rotation. Measurements of aER were performed while the latissimus dorsi was activated in its new function of external rotation with concomitant activation (coactivation) of its native functions (adduction and extension). Bilateral surface electromyographic (EMG) activity was recorded during aER measurements and the strength testing procedure (EMG activity ratio: with/without CoA). Patients were divided into two groups (excellent/good vs fair/poor) according to the results of the ASES and UCLA scores. The mean follow-up was 57.8 ± 25.2 months. Subdivided by clinical scores, the superior outcome group lost aER with CoA, whereas the inferior outcome group gained aER (UCLA score: -2.2° ± 7.4° vs +4.3° ± 4.1°; P = .031). Patients with inferior outcomes in the ASES score showed higher latissimus dorsi EMG activity ratios (P = .027), suggesting an inadequate motor learning process. Isometric strength testing revealed that the latissimus dorsi transfer had significantly greater activity compared with the contralateral side (external rotation, P = .008; abduction, P = .006) but did not have comparable strength (external rotation, P = .017; abduction, P = .009). Patients with inferior clinical results were more likely to be dependent on CoA to gain external rotation. Therefore, CoA testing may be used as a tool to evaluate the status of postoperative motor learning after latissimus dorsi transfer. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  16. Electromyographic Activity of the Gluteus Maximus on the Weight-Bearing Side During Lateral and Frontal Wall Press Exercises

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    Ishida

    2016-01-01

    Full Text Available Background The lateral wall press (WP exercise is one of the weight-bearing exercises used in gluteal muscle strengthening programs. However, little is known about the muscle activity level of the gluteus maximus (Gmax on the weight-bearing side during the lateral WP exercise. The primary actions of the Gmax are hip extension and hip external rotation. In addition, the superior area of the Gmax also functions as a hip abductor. We hypothesized that not only lateral but also frontal WP exercise might be suitable for Gmax strengthening. Objectives The purpose of this study was to quantify electromyographic (EMG activity of Gmax in weight-bearing side during lateral and frontal WP exercise. Patients and Methods Twelve healthy women (university students participated in this study. The surface EMG was used to quantify the activity of the Gmax on the weight-bearing side during lateral and frontal WP exercises. The exercises were done with opposite leg. A paired t-test was used to examine the significance of differences in the Gmax activity between the lateral and frontal WP exercises. Results The means ± standard deviations of the averaged EMG during the lateral and frontal WP exercises were 40.1 ± 19.1, and 23.7 ± 11.3 µV, respectively. Those of the percent maximal voluntary contraction during the lateral and frontal WP exercises were 51.4 ± 29.7, and 31.3 ± 20.5, respectively. Gmax activity during the lateral WP exercise was significantly higher than that during the frontal WP exercise Conclusions The results of this study indicate that the lateral WP exercise is more suitable than the frontal WP exercise for strengthening the Gmax on the weight-bearing side.

  17. An electromyographic-based test for estimating neuromuscular fatigue during incremental treadmill running

    International Nuclear Information System (INIS)

    Camic, Clayton L; Kovacs, Attila J; Hill, Ethan C; Calantoni, Austin M; Yemm, Allison J; Enquist, Evan A; VanDusseldorp, Trisha A

    2014-01-01

    The purposes of the present study were two fold: (1) to determine if the model used for estimating the physical working capacity at the fatigue threshold (PWC FT ) from electromyographic (EMG) amplitude data during incremental cycle ergometry could be applied to treadmill running to derive a new neuromuscular fatigue threshold for running, and (2) to compare the running velocities associated with the PWC FT , ventilatory threshold (VT), and respiratory compensation point (RCP). Fifteen college-aged subjects (21.5  ±  1.3 y, 68.7  ±  10.5 kg, 175.9  ±  6.7 cm) performed an incremental treadmill test to exhaustion with bipolar surface EMG signals recorded from the vastus lateralis. There were significant (p < 0.05) mean differences in running velocities between the VT (11.3  ±  1.3 km h −1 ) and PWC FT (14.0  ±  2.3 km h −1 ), VT and RCP (14.0  ±  1.8 km h −1 ), but not the PWC FT and RCP. The findings of the present study indicated that the PWC FT model could be applied to a single continuous, incremental treadmill test to estimate the maximal running velocity that can be maintained prior to the onset of neuromuscular fatigue. In addition, these findings suggested that the PWC FT , like the RCP, may be used to differentiate the heavy from severe domains of exercise intensity. (paper)

  18. Averaged EMG profiles in jogging and running at different speeds

    NARCIS (Netherlands)

    Gazendam, Marnix G. J.; Hof, At L.

    EMGs were collected from 14 muscles with surface electrodes in 10 subjects walking 1.25-2.25 m s(-1) and running 1.25-4.5 m s(-1). The EMGs were rectified, interpolated in 100% of the stride, and averaged over all subjects to give an average profile. In running, these profiles could be decomposed

  19. Electromyographic Evaluation of the Effect of Lined Dentures on Masticatory Muscle Activity in Edentulous Subjects.

    Science.gov (United States)

    Rastogi, Abhishek; Srivastava, Shitij; Gaur, Abhishek; Dupare, Arun; Rastogi, Shiksha; Kamatagi, Laxmikant

    2015-08-01

    The purpose of this study was to examine changes in relative electromyographic (EMG) activities of temporal and masseter muscles after relining the dentures with silicone and acrylic-resin based denture liners. Conventional complete dentures were fabricated for 20 edentulous patients. One month after completing adjustments of the dentures, electromyography of the masseter and temporalis muscle during maximum intercuspation was recorded. The dentures were then relined with a silicone denture liner and after an adaptation period of one month, were again subjected for electromyographic evaluation. Further, the dentures were relined with acrylic denture liner and subjected to electromyographic evaluation. Data was analysed using Statistical Package for Social Sciences (SPSS) version 15.0. Intergroup comparisons were done using ANOVA followed by post-hoc assessments using Tukey HSD test. Mean amplitude and duration with conventional dentures was found to be significantly lower as compared to silicone lined and acrylic lined dentures for all the comparisons. Statistically, no significant difference between silicone lined and acrylic lined dentures was observed for any of the comparisons. Within the limitations of this experimental design, it was concluded that relining significantly increases electromyographic activity of the masseter and temporalis muscles. Thus, resulting in an improved biting force, chewing efficiency and masticatory performance. There were no significant differences between silicone and acrylic based denture liners for both electromyographic variables.

  20. Surface EMG and muscle fatigue: multi-channel approaches to the study of myoelectric manifestations of muscle fatigue.

    Science.gov (United States)

    Marco, Gazzoni; Alberto, Botter; Taian, Vieira

    2017-05-01

    In a broad view, fatigue is used to indicate a degree of weariness. On a muscular level, fatigue posits the reduced capacity of muscle fibres to produce force, even in the presence of motor neuron excitation via either spinal mechanisms or electric pulses applied externally. Prior to decreased force, when sustaining physically demanding tasks, alterations in the muscle electrical properties take place. These alterations, termed myoelectric manifestation of fatigue, can be assessed non-invasively with a pair of surface electrodes positioned appropriately on the target muscle; traditional approach. A relatively more recent approach consists of the use of multiple electrodes. This multi-channel approach provides access to a set of physiologically relevant variables on the global muscle level or on the level of single motor units, opening new fronts for the study of muscle fatigue; it allows for: (i) a more precise quantification of the propagation velocity, a physiological variable of marked interest to the study of fatigue; (ii) the assessment of regional, myoelectric manifestations of fatigue; (iii) the analysis of single motor units, with the possibility to obtain information about motor unit control and fibre membrane changes. This review provides a methodological account on the multi-channel approach for the study of myoelectric manifestation of fatigue and on the experimental conditions to which it applies, as well as examples of their current applications.

  1. Evaluation of muscle fatigue of wheelchair basketball players with spinal cord injury using recurrence quantification analysis of surface EMG.

    Science.gov (United States)

    Uzun, S; Pourmoghaddam, A; Hieronymus, M; Thrasher, T A

    2012-11-01

    Wheelchair basketball is the most popular exercise activity among individuals with spinal cord injury (SCI). The purpose of this study was to investigate muscular endurance and fatigue in wheelchair basketball athletes with SCI using surface electromyography (SEMG) and maximal torque values. SEMG characteristics of 10 wheelchair basketball players (WBP) were compared to 13 able-bodied basketball players and 12 sedentary able-bodied subjects. Participants performed sustained isometric elbow flexion at 50% maximal voluntary contraction until exhaustion. Elbow flexion torque and SEMG signals were recorded from three elbow flexor muscles: biceps brachii longus, biceps brachii brevis and brachioradialis. SEMG signals were clustered into 0.5-s epochs with 50% overlap. Root mean square (RMS) and median frequency (MDF) of SEMG signals were calculated for each muscle and epoch as traditional fatigue monitoring. Recurrence quantification analysis was used to extract the percentage of determinism (%DET) of SEMG signals. The slope of the %DET for basketball players and WBP showed slower increase with time than the sedentary able-bodied control group for three different elbow flexor muscles, while no difference was observed for the slope of the %DET between basketball and WBP. This result indicated that the athletes are less fatigable during the task effort than the nonathletes. Normalized MDF slope decay exhibited similar results between the groups as %DET, while the slope of the normalized RMS failed to show any significant differences among the groups (p > 0.05). MDF and %DET could be useful for the evaluation of muscle fatigue in wheelchair basketball training. No conclusions about special training for WBP could be determined.

  2. Ventilatory threshold during incremental running can be estimated using EMG shorts.

    Science.gov (United States)

    Tikkanen, Olli; Hu, Min; Vilavuo, Toivo; Tolvanen, Pekka; Cheng, Sulin; Finni, Taija

    2012-04-01

    The present study examined whether shorts with textile electromyographic (EMG) electrodes can be used to detect second ventilatory threshold (V(T2)) during incremental treadmill running. Thirteen recreationally active (REC) and eight endurance athletes were measured for EMG, heart rate, blood lactate and respiratory gases during VO(2max) test (3 min ramps, 1 km·h(-1) increments). V(T)(2), onset of blood lactate accumulation (OBLA) and EMG threshold (EMG(T)) were determined. In athletes, OBLA occurred at 56 ± 6 mL·kg(-1)·min(-1), V(T2) occurred at 59 ± 6 mL·kg(-1)·min(-1), and EMG(T) at 62 ± 6 mL·kg(-1)·min(-1) without significant differences between methods (analysis of variance: ANOVA). In REC participants, OBLA occurred at 40 ± 10 mL·kg(-1)·min(-1), V(T2) occurred at 43 ± 7 mL·kg(-1)·min(-1), and EMG(T) at 41 ± 9 mL·kg(-1)·min(-1) without significant differences between methods (ANOVA). For the entire group, correlation between EMG(T) and V(T2) was 0.86 (P < 0.001) and 0.84 (P < 0.001) between EMG(T) and OBLA. Limits of agreement between EMG(T) and V(T2) were narrower in athletes than in REC participants. Thus, it is concluded that estimation of V(T2) using EMG(T) in athletes is more valid than in REC participants. In practice, experienced runners could use online feedback from EMG garments to monitor whether their running intensity is near V(T2). © 2012 Institute of Physics and Engineering in Medicine

  3. Correlated EMG Oscillations between Antagonists during Cocontraction in Men.

    Science.gov (United States)

    Yoshitake, Yasuhide; Kanehisa, Hiroaki; Shinohara, Minoru

    2017-03-01

    The purpose of this study was to determine the modulation of common low-frequency oscillations in pools of motor units across antagonistic muscles because of the difference in the activation level of pools of spinal motor neurons and the presence of neuromuscular fatigue during intended cocontraction. Ten healthy young men (21.8 ± 1.5 yr) performed intended steady cocontractions of elbow flexors and extensors at maximal and a submaximal (10% of maximal EMG) effort. The submaximal cocontraction was repeated after sustained maximal contraction of elbow flexors. Surface EMG was recorded from the biceps brachii and triceps brachii muscles. Correlated EMG oscillations between the antagonistic muscles were quantified by the cross-correlation function (CCF) using rectified EMG for the EMG for the 3- to 15-Hz bands. The positive CCF peak in rectified EMG EMG, a negative CCF peak (i.e., out-of-phase oscillations) during submaximal cocontraction was smaller compared with maximal cocontraction but increased after the sustained contraction. Across subjects, the degree of reduction in maximal EMG amplitude after the sustained contraction was correlated with the amount of change in the CCF peak in EMG oscillations between antagonistic muscles occur during intended cocontraction, and 2) the magnitude of these correlated oscillations increases with the activation level of pools of spinal motor neurons and neuromuscular fatigue.

  4. EMG patterns during assisted walking in the exoskeleton

    Directory of Open Access Journals (Sweden)

    Francesca eSylos-Labini

    2014-06-01

    Full Text Available Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns.

  5. EMG patterns during assisted walking in the exoskeleton

    Science.gov (United States)

    Sylos-Labini, Francesca; La Scaleia, Valentina; d'Avella, Andrea; Pisotta, Iolanda; Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco; Wang, Shiqian; Wang, Letian; van Asseldonk, Edwin; van der Kooij, Herman; Hoellinger, Thomas; Cheron, Guy; Thorsteinsson, Freygardur; Ilzkovitz, Michel; Gancet, Jeremi; Hauffe, Ralf; Zanov, Frank; Lacquaniti, Francesco; Ivanenko, Yuri P.

    2014-01-01

    Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts, and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns. PMID:24982628

  6. Simultaneous Recording and Analysis of Uterine and Abdominal Muscle Electromyographic Activity in Nulliparous Women During Labor.

    Science.gov (United States)

    Qian, Xueya; Li, Pin; Shi, Shao-Qing; Garfield, Robert E; Liu, Huishu

    2017-03-01

    To record and characterize electromyography (EMG) from the uterus and abdominal muscles during the nonlabor to first and second stages of labor and to define relationships to contractions. Nulliparous patients without any treatments were used (n = 12 nonlabor stage, 48 during first stage and 33 during second stage). Electromyography of both uterine and abdominal muscles was simultaneously recorded from electrodes placed on patients' abdominal surface using filters to separate uterine and abdominal EMG. Contractions of muscles were also recorded using tocodynamometry. Electromyography was characterized by analysis of various parameters. During the first stage of labor, when abdominal EMG is absent, uterine EMG bursts temporally correspond to contractions. In the second stage, uterine EMG bursts usually occur at same frequency as groups of abdominal bursts and precede abdominal bursts, whereas abdominal EMG bursts correspond to contractions and are accompanied by feelings of "urge to push." Uterine EMG increases progressively from nonlabor to second stage of labor. (1) Uterine EMG activity can be separated from abdominal EMG events by filtering. (2) Uterine EMG gradually evolves from the antepartum stage to the first and second stages of labor. (3) Uterine and abdominal EMG reflect electrical activity of the muscles during labor and are valuable to assess uterine and abdominal muscle events that control labor. (4) During the first stage of labor uterine, EMG is responsible for contractions, and during the second stage, both uterine and abdominal muscle participate in labor.

  7. Effects of Velocity on Electromyographic, Mechanomyographic, and Torque Responses to Repeated Eccentric Muscle Actions.

    Science.gov (United States)

    Hill, Ethan C; Housh, Terry J; Camic, Clayton L; Smith, Cory M; Cochrane, Kristen C; Jenkins, Nathaniel D M; Cramer, Joel T; Schmidt, Richard J; Johnson, Glen O

    2016-06-01

    The purposes of this study were to examine the effects of the velocity of repeated eccentric muscle actions on the torque and neuromuscular responses during maximal isometric and eccentric muscle actions. Twelve resistance-trained men performed 30 repeated, maximal, eccentric, isokinetic muscle actions at randomly ordered velocities of 60, 120, or 180°·s on separate days. Maximal voluntary isometric contractions (MVICs) were performed before (pretest) and after (posttest) the repeated eccentric muscle actions on each day. Eccentric isokinetic peak torque (EIPT) values were the averages of the first 3 and last 3 repetitions of the 30 repeated eccentric muscle actions. During the EIPT and MVIC muscle actions, electromyographic (EMG) and mechanomyographic (MMG) amplitude (EMG AMP and MMG AMP) and mean power frequency (EMG MPF and MMG MPF) values were assessed. These results indicated that the repeated eccentric muscle actions had no effects on EIPT, or the EMG AMP, EMG MPF, or MMG MPF values assessed during the EIPT muscle actions, but decreased MMG AMP. The repeated eccentric muscle actions, however, decreased MVIC torque, and also the EMG AMP and MMG MPF values assessed during the MVIC muscle actions, but increased MMG AMP. The results indicated that the velocity of the repeated eccentric muscle actions affected the MVIC torque responses, but not EIPT or any of the neuromuscular parameters. Furthermore, there are differences in the torque and neuromuscular responses for isometric vs. eccentric muscle actions after repeated eccentric muscle actions.

  8. A Novel EMG Interface for Individuals With Tetraplegia to Pilot Robot Hand Grasping.

    Science.gov (United States)

    Tigra, Wafa; Navarro, Benjamin; Cherubini, Andrea; Gorron, X; Gelis, Anthony; Fattal, Charles; Guiraud, David; Azevedo Coste, Christine

    2018-02-01

    This paper introduces a new human-machine interface for individuals with tetraplegia. We investigated the feasibility of piloting an assistive device by processing supra-lesional muscle responses online. The ability to voluntarily contract a set of selected muscles was assessed in five spinal cord-injured subjects through electromyographic (EMG) analysis. Two subjects were also asked to use the EMG interface to control palmar and lateral grasping of a robot hand. The use of different muscles and control modalities was also assessed. These preliminary results open the way to new interface solutions for high-level spinal cord-injured patients.

  9. Electromyographic patterns of lower limb muscles during apprehensive gait in younger and older female adults.

    Science.gov (United States)

    Hallal, Camilla Zamfolini; Marques, Nise Ribeiro; Spinoso, Deborah Hebling; Vieira, Edgar Ramos; Gonçalves, Mauro

    2013-10-01

    Investigate the influence of apprehensive gait on activation and cocontraction of lower limb muscles of younger and older female adults. Data of 17 younger (21.47±2.06yr) and 18 older women (65.33±3.14yr) were considered for this study. Participants walked on the treadmill at two different conditions: normal gait and apprehensive gait. The surface electromyographic signals (EMG) were recorded during both conditions on: rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), tibialis anterior (TA), gastrocnemius lateralis (GL), and soleus (SO). Apprehensive gait promoted greater activation of thigh muscles than normal gait (F=5.34 and p=0.007, for significant main effect of condition; RF, p=0.002; VM, pmuscles than younger women (F=4.05 and p=0.019, for significant main effect of groups; VM/BF, p=0.010; TA/GL, p=0.007; and TA/SO, p=0.002). Apprehensive gait promoted greater activation of thigh muscles and older adults had greater cocontraction of knee and ankle stabilizer muscles. Thus, apprehensive gait may leads to increased percentage of neuromuscular capacity, which is associated with greater cocontraction and contribute to the onset of fatigue and increased risk of falling in older people. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. The Design of EMG Measurement System for Arm Strength Training Machine

    Directory of Open Access Journals (Sweden)

    Tze-Yee Ho

    2015-01-01

    Full Text Available The setup of interactive communication between arm strength training machine and the people will make exercise and rehabilitation therapy become more friendly. The employment of electromyographic not only can help physical therapy but also can achieve more effective rehabilitation. Both of the system hardware and software of the arm strength training machine with EMG system are well designed and described. The fundamental design of electromyographic measurement system based on a microcontroller is analyzed and discussed. The software programming is developed in MPLAB integrated development environment from the Microchip Technology Inc. and the friendly user interface is created as well. Finally, an arm strength training machine with electromyographic control system is realized and demonstrated. The experimental results show the feasibility and fidelity of the complete designed system.

  11. Effect of a jig on EMG activity in different orofacial pain conditions.

    Science.gov (United States)

    Bodere, Celine; Woda, Alain

    2008-01-01

    The bite stop (jig) is commonly used in clinical practice. It has been recommended as a simple means to routinely record or provide centric relation closure and, more recently, to reduce migraines and tension-type headaches. However, the reason for the jig effect has yet to be explained. This study tested the hypothesis that it works through a decrease in masticatory muscle activity. The effect of a jig placed on the maxillary anterior teeth was investigated by recording the electromyographic (EMG) activity of the superficial masseter and anterior temporal muscles at postural position and when swallowing on the jig. EMG recordings were obtained from 2 groups of pain patients (myofascial and neuropathic) and from 2 groups of pain-free patients (disc derangement and controls) unaware of the role of dental occlusion treatments. EMG activity in postural position was higher in pain groups than in pain-free groups. The jig strongly but temporarily decreased the postural EMG activity for masseter muscles in all groups except for the neuropathic group and for temporal muscles in the myofascial group. The EMG activity when swallowing with the jig was reduced in control, disc derangement, and myofascial groups; however, EMG "hyperactivity" in the neuropathic pain group seemed to be locked. The decrease of postural EMG activity, especially in the myofascial group, was short lasting and cannot be considered as evidence to support the hypothesis of a long-term muscle relaxation jig effect. However, the results may uphold certain short-term clinical approaches.

  12. EMG amplitude, fatigue threshold, and time to task failure: A meta-analysis.

    Science.gov (United States)

    McCrary, J Matt; Ackermann, Bronwen J; Halaki, Mark

    2017-11-11

    Electromyographic (EMG) fatigue threshold (EMG FT ) is utilised as a correlate of critical power, torque, and force thresholds that establishes a theoretical exercise intensity-the power, torque, or force at which the rate of change of EMG amplitude (ΔEM¯G) is zero-below which neuromuscular fatigue is negligible and unpredictable. Recent studies demonstrating neuromuscular fatigue below critical thresholds raise questions about the construct validity of EMG FT . The purpose of this analysis is to evaluate the construct validity of EMGFT by aggregating ΔEM¯G and time to task failure (T lim ) data. Meta-analysis. Database search of MEDLINE, SPORTDiscus, Web of Science, and Cochrane (inception - September 2016) conducted using terms relevant to EMG and muscle fatigue. Inclusion criteria were studies reporting agonist muscle EMG amplitude data during constant force voluntary isometric contractions taken to task failure. Linear and nonlinear regression models were used to relate ΔEM¯G and T lim data extracted from included studies. Regression analyses included data from 837 healthy adults from 43 studies. Relationships between ΔEM¯G and T lim were strong in both nonlinear (R 2 =0.65) and linear (R 2 =0.82) models. ΔEM¯G at EMG FT was significantly nonzero overall and in 3 of 5 cohorts in the nonlinear model (pEMG FT lacks face validity as currently calculated; models for more precise EMG FT calculation are proposed. A new framework for prediction of task failure using EMG amplitude data alone is presented. The ΔEM¯G vs. Tlim relationship remains consistent across sexes and force vs. position tasks. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  13. Wavelet analysis for detection of phasic electromyographic activity in sleep: influence of mother wavelet and dimensionality reduction.

    Science.gov (United States)

    Fairley, Jacqueline A; Georgoulas, George; Smart, Otis L; Dimakopoulos, George; Karvelis, Petros; Stylios, Chrysostomos D; Rye, David B; Bliwise, Donald L

    2014-05-01

    Phasic electromyographic (EMG) activity during sleep is characterized by brief muscle twitches (duration 100-500ms, amplitude four times background activity). High rates of such activity may have clinical relevance. This paper presents wavelet (WT) analyses to detect phasic EMG, examining both Symlet and Daubechies approaches. Feature extraction included 1s epoch processing with 24 WT-based features and dimensionality reduction involved comparing two techniques: principal component analysis and a feature/variable selection algorithm. Classification was conducted using a linear classifier. Valid automated detection was obtained in comparison to expert human judgment with high (>90%) classification performance for 11/12 datasets. Published by Elsevier Ltd.

  14. Are chronic neck pain, scapular dyskinesis and altered scapulothoracic muscle activity interrelated?: A case-control study with surface and fine-wire EMG.

    Science.gov (United States)

    Castelein, Birgit; Cools, Ann; Parlevliet, Thierry; Cagnie, Barbara

    2016-12-01

    The function of the scapula is important in normal neck function and might be disturbed in patients with neck pain. The surrounding muscular system is important for the function of the scapula. To date, it is not clear if patients with idiopathic neck pain show altered activity of these scapulothoracic muscles. Therefore, the objective of this study was to investigate differences in deeper and superficial lying scapulothoracic muscle activity between patients with idiopathic neck pain and healthy controls during arm elevation, and to identify the influence of scapular dyskinesis on muscle activity. Scapular dyskinesis was rated with the yes/no method. The deeper lying (Levator Scapulae, Pectoralis Minor (Pm) and Rhomboid major) and superficial lying (Trapezius and Serratus Anterior) scapulothoracic muscles' activity was investigated with fine-wire and surface EMG, respectively, in 19 female subjects with idiopathic neck pain (age 28.3±10.1years, average duration of neck pain 45.6±36.3months) and 19 female healthy control subjects (age 29.3±11.7years) while performing scaption and towel wall slide. Possible interactions or differences between subject groups, scapular dyskinesis groups or phases of the task were studied with a linear mixed model. Higher Pm activity during the towel wallslide (p=0.024, mean difference 8.8±3.3% MVIC) was shown in patients with idiopathic neck pain in comparison with healthy controls. For the MT, a significant group∗dyskinesis interaction effect was found during scaption which revealed that patients with neck pain and scapular dyskinesis showed lower Middle Trapezius (MT) activity in comparison with healthy controls with scapular dyskinesis (p=0.029, mean difference 5.1±2.2% MVIC). In the presence of idiopathic neck pain, higher Pm activity during the towel wallslide was found. Patients with neck pain and scapular dyskinesis showed lower MT activity in comparison with healthy controls with scapular dyskinesis during scaption

  15. sEMG Signal Acquisition Strategy towards Hand FES Control

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    Cinthya Lourdes Toledo-Peral

    2018-01-01

    Full Text Available Due to damage of the nervous system, patients experience impediments in their daily life: severe fatigue, tremor or impaired hand dexterity, hemiparesis, or hemiplegia. Surface electromyography (sEMG signal analysis is used to identify motion; however, standardization of electrode placement and classification of sEMG patterns are major challenges. This paper describes a technique used to acquire sEMG signals for five hand motion patterns from six able-bodied subjects using an array of recording and stimulation electrodes placed on the forearm and its effects over functional electrical stimulation (FES and volitional sEMG combinations, in order to eventually control a sEMG-driven FES neuroprosthesis for upper limb rehabilitation. A two-part protocol was performed. First, personalized templates to place eight sEMG bipolar channels were designed; with these data, a universal template, called forearm electrode set (FELT, was built. Second, volitional and evoked movements were recorded during FES application. 95% classification accuracy was achieved using two sessions per movement. With the FELT, it was possible to perform FES and sEMG recordings simultaneously. Also, it was possible to extract the volitional and evoked sEMG from the raw signal, which is highly important for closed-loop FES control.

  16. Using gastrocnemius sEMG and plasma α-synuclein for the prediction of freezing of gait in Parkinson's disease patients.

    Directory of Open Access Journals (Sweden)

    Xiao-Ying Wang

    Full Text Available Freezing of gait (FOG is a complicated gait disturbance in Parkinson's disease (PD and a relevant subclinical predictor algorithm is lacking. The main purpose of this study is to explore the potential value of surface electromyograph (sEMG and plasma α-synuclein levels as predictors of the FOG seen in PD. 21 PD patients and 15 normal controls were recruited. Motor function was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS and Freezing of gait questionnaire (FOG-Q. Simultaneously, gait analysis was also performed using VICON capture system in PD patients and sEMG data was recorded as well. Total plasma α-synuclein was quantitatively assessed by Luminex assay in all participants. Recruited PD patients were classified into two groups: PD patients with FOG (PD+FOG and without FOG (PD-FOG, based on clinical manifestation, the results of the FOG-Q and VICON capture system. PD+FOG patients displayed higher FOG-Q scores, decreased walking speed, smaller step length, smaller stride length and prolonged double support time compared to the PD-FOG in the gait trial. sEMG data indicated that gastrocnemius activity in PD+FOG patients was significantly reduced compared to PD-FOG patients. In addition, plasma α-synuclein levels were significantly decreased in the PD+FOG group compared to control group; however, no significant difference was found between the PD+FOG and PD-FOG groups. Our study revealed that gastrocnemius sEMG could be used to evaluate freezing gait in PD patients, while plasma α-synuclein might discriminate freezing of gait in PD patients from normal control, though no difference was found between the PD+FOG and PD-FOG groups.

  17. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    OpenAIRE

    Serefoglu, Abdullah; Sekir, Ufuk; G?r, Hakan; Akova, Bedrettin

    2017-01-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) ...

  18. Change in bite force and electromyographic activity of masticatory muscle in accordance with change of occlusal plane.

    Science.gov (United States)

    Park, Min-Kyu; Cho, Sung-Min; Yun, Kyoung-In; Park, Je-Uk

    2012-08-01

    The purpose of the present study was to evaluate effects of occlusal plane on masticatory function (biting force, masticatory muscle activity, biting efficiency) after bimaxillary orthognathic surgery. The subjects of the present study consisted of a group of 55 adults who had undergone bimaxillary surgery more than 6 months earlier. Lateral cephalographs, bite force, and electromyographic measurements of the anterior temporal [EMG(t)] and masseter muscles [EMG(m)] were recorded before and after bimaxillary surgery. Statistical analyses were performed. In the increased occlusal plane group, the frequency of decreased EMG(t) was significantly high. The frequency of increased EMG(t) was also significantly high in the decreased occlusal plane group. A negative correlation was found between the postoperative occlusal plane angle and the biting force efficiency change. No significant difference was found between the group that moved from an abnormal to a normal range and the group that moved from a normal to an abnormal range. The occlusal plane change was significantly greater in the decreased EMG(t) group than in the increased EMG(t) group. The value of EMG(t) was related to the changes in the occlusal plane, and the biting efficiency was affected by the postoperative occlusal plane angle. However, normalization of the occlusal plane might not play a major role in masticatory function. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  19. Oynophagia in patients after dental extraction: surface electromyography study

    Directory of Open Access Journals (Sweden)

    Nahlieli Oded

    2006-10-01

    Full Text Available Abstract Objectives Surface electromyographic (sEMG studies were performed on 40 adult patients following extraction of lower third and second molars to research the approach and limitations of sEMG evaluation of their odynophagia complaints. Methods Parameters evaluated during swallowing and drinking include the timing, number of swallows per 100 cc of water, and range (amplitude of EMG activity of m. masseter, infrahyoid and submental-submandibular group. The above mentioned variables (mean + standard deviation were measured for the group of dental patients (n = 40 and control group of healthy adults (n = 40. Results The duration of swallows and drinking in all tests showed increase in dental patients' group, in which this tendency is statistically significant. There was no statistically significant difference between male and female adults' duration and amplitude of muscle activity during continuous drinking in both groups (p = 0.05. The mean of electric activity (in μV of m. masseter was significantly lower in the dental patients' group in comparison with control group. The electric activity of submental-submandimular and infrahyoid muscle groups was the same in both groups. Conclusion Surface EMG of swallowing is a simple and reliable noninvasive method for evaluation of odynophagia/dysphagia complaints following dental extraction with low level of discomfort of the examination. The surface EMG studies prove that dysphagia following dental extraction and molar surgery has oral origin, does not affect pharingeal segment and submental-submandibular muscle group. This type of dysphagia has clear EMG signs: increased duration of single swallow, longer drinking time, low range of electric activity of m. masseter, normal range of activity of submental-submandibular muscle group, and the "dry swalow" aftereffect. The data can be used for evaluation of complaints and symptoms, as well as for comparison purposes in pre- and postoperative stages and

  20. A dynamical model improves reconstruction of handwriting from multichannel electromyographic recordings

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    Elizaveta eOkorokova

    2015-10-01

    Full Text Available In recent years, several assistive devices have been proposed to reconstruct arm and hand movements from electromyographic (EMG activity. Although simple to implement and potentially useful to augment many functions, such myoelectric devices still need improvement before they become practical. Here we considered the problem of reconstruction of handwriting from multichannel EMG activity. Previously, linear regression methods (e.g. the Wiener filter have been utilized for this purpose with some success. To improve reconstruction accuracy, we implemented the Kalman filter, which allows to fuse two information sources: the physical characteristics of handwriting and the activity of the leading hand muscles, registered by the EMG. Applying the Kalman filter, we were able to convert eight channels of EMG activity recorded from the forearm and the hand muscles into smooth reconstructions of handwritten traces. The filter operates in a causal manner and acts as a true predictor utilizing the EMGs from the past only, which makes the approach suitable for real-time operations. Our algorithm is appropriate for clinical neuroprosthetic applications and computer peripherals. Moreover, it is applicable to a broader class of tasks where predictive myoelectric control is needed.

  1. TIME-OF-DAY EFFECTS ON EMG PARAMETERS DURING THE WINGATE TEST IN BOYS

    Directory of Open Access Journals (Sweden)

    Hichem Souissi

    2012-09-01

    Full Text Available In boys, muscle power and strength fluctuate with time-of-day with morning nadirs and afternoon maximum values. However, the exact underlying mechanisms of this daily variation are not studied yet. Thus, the purpose of this study was to examine the time-of-day effects on electromyographic (EMG parameters changes during a Wingate test in boys. Twenty-two boys performed a 30-s Wingate test (measurement of muscle power and fatigue at 07:00 and 17:00-h on separate days. Surface EMG activity was recorded in the Vastus lateralis, rectus femoris and vastus medialis muscles throughout the test and analyzed over a 5-s span. The root-mean-square (RMS and mean-power-frequency (MPF were calculated. Neuromuscular efficiency (NME was estimated from the ratio of power to RMS. Muscle power (8.22 ± 0.92 vs. 8.75 ± 0.99 W·kg-1 for peak power and 6.96 ± 0. 72 vs. 7.31 ± 0.77 W·kg-1 for mean power, p < 0.001 and fatigue (30.27 ± 7.98 vs. 34.5 ± 10. 15 %, p < 0.05 during the Wingate test increased significantly from morning to evening. Likewise, MPF (102.14 ± 18.15 vs. 92.38 ± 12.39 Hz during the first 5-s, p < 0.001 and NME (4.78 ± 1.7 vs. 3.88 ± 0.79 W·mV-1 during the first 5-s, p < 0.001 were higher in the evening than the morning; but no significant time-of-day effect was noticed for RMS. Taken together, these results suggest that peripheral mechanisms are more likely the cause of the child's diurnal variations of muscle power and fatigue during the Wingate test

  2. Control engineering and electromyographic kinesiology analyses of normal human gait.

    Science.gov (United States)

    Hashimoto, F; Ogawa, R; Kameyama, O

    2000-01-01

    In this study, we analyzed the electrical activity patterns of the antagonistic bi-articular and mono-articular muscles of both legs during normal gait cycles, in terms of electromyographic (EMG) kinesiology and control engineering. For control engineering analyses, we utilized a mechanical two-joint link model equipped with antagonistic pairs of bi-articular and mono-articular muscles. It was confirmed that the coordinated activity pattern, in which the bi-articular muscles of the rectus femoris (Rf) and the medial hamstrings (Mh) showed criss-cross EMG patterns, and the mono-articular muscles of the gluteus maximus and the vastus medialis showed sustained activities during the early stance phase in the gait cycle, contributed to the output force control and the output force direction control. Reversal of Rf and Mh activities was responsible for changes in the output force direction during the heel contact period. The results obtained here strongly highlight the importance of and necessity for control engineering evaluation of coordinated muscle activities of bi-articular and mono-articular antagonistic muscles for analyses not only of gait but also of sports injuries.

  3. The Vastus Medialis Oblique: Vastus Lateralis Electromyographic Intensity Ratio During Squat with Hip Adduction in Athletes with and Without Patellofemoral Pain Syndrome

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    Farhad Reza-zadeh

    2012-07-01

    Full Text Available Objective: This study was designed to compare vastus medialis oblique (VMO: vastus lateralis longus (VLL electromyographic intensity ratio during squat with hip adduction in athletes with and without patellofemoral pain syndrome (PFPS. Materials & Methods: In this non-experimental and case-control study, 16 male athletes with PFPS were selected purposefully and 16 healthy male athletes aged 18-30 years from national teams (Volleyball, Handball and Taekwondo were matched based on variables such as weight, height, age, dominancy. All subjects selected based on inclusion and exclusion criteria. EMG activity of VMO and VLL muscles was recorded by surface electrodes with Telemetric EMG System at 15, 30 and 45 degrees of squat and VMO: VLL ratio was calculated. One way ANOVA was used to compare these muscles ratio between two groups. Results: The ratio of VMO: VLL in both groups with and without PFPS in almost all angles were lower than one. However, healthy athletes had lower ratios. Also, there were no significant differences in VMO: VLL ratio at various angles. Conclusion: It seems that sports activities prevent VMO weakening in athletes. However, VMO: VLL ratio in athletes with and without patellofemoral pain does not influence by this syndrome.

  4. Electromyographic analysis of gluteus maximus and hamstring activity during the supine resisted hip extension exercise versus supine unilateral bridge to neutral.

    Science.gov (United States)

    Youdas, James W; Hartman, James P; Murphy, Brooke A; Rundle, Ashley M; Ugorowski, Jenna M; Hollman, John H

    2017-02-01

    Hip extension strengthening exercises which maximize gluteus maximus contributions and minimize hamstring influences may be beneficial for persons with hip pain. This study's aim was to compare muscle activation of the gluteus maximus and hamstrings from healthy subjects during a supine resisted hip extension exercise versus supine unilateral bridge to neutral. Surface electromyographic (EMG) signals were obtained from the right gluteus maximus and hamstrings in 13 healthy male and 13 healthy female subjects. Maximum voluntary isometric contractions (MVICs) were collected to normalize data and permit meaningful comparisons across muscles. Peak median activation of the gluteus maximus was 33.8% MVIC for the bridge and 34.7% MVIC for the hip extension exercise, whereas peak median recruitment for hamstrings was 28.4% MVIC for the bridge and 51% MVIC for the hip extension exercise. The gluteus maximus to hamstrings ratio was compared between the two exercises using the Wilcoxon signed-ranks test (α = 0.05). The ratio (p = 0.014) was greater in the supine unilateral bridge (median = 111.3%) than supine hip extension exercise (median = 59.2%), suggesting a reduction of hamstring recruitment in the unilateral bridge to neutral compared to the supine resisted hip extension exercise. The supine hip extension exercise demonstrated higher EMG activity of hamstrings in comparison with supine unilateral bridge and, therefore, may be less appropriate in subjects who need to increase gluteus maximus activation.

  5. Evaluation of EMG processing techniques using Information Theory

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    Felice Carmelo J

    2010-11-01

    Full Text Available Abstract Background Electromyographic signals can be used in biomedical engineering and/or rehabilitation field, as potential sources of control for prosthetics and orthotics. In such applications, digital processing techniques are necessary to follow efficient and effectively the changes in the physiological characteristics produced by a muscular contraction. In this paper, two methods based on information theory are proposed to evaluate the processing techniques. Methods These methods determine the amount of information that a processing technique is able to extract from EMG signals. The processing techniques evaluated with these methods were: absolute mean value (AMV, RMS values, variance values (VAR and difference absolute mean value (DAMV. EMG signals from the middle deltoid during abduction and adduction movement of the arm in the scapular plane was registered, for static and dynamic contractions. The optimal window length (segmentation, abduction and adduction movements and inter-electrode distance were also analyzed. Results Using the optimal segmentation (200 ms and 300 ms in static and dynamic contractions, respectively the best processing techniques were: RMS, AMV and VAR in static contractions, and only the RMS in dynamic contractions. Using the RMS of EMG signal, variations in the amount of information between the abduction and adduction movements were observed. Conclusions Although the evaluation methods proposed here were applied to standard processing techniques, these methods can also be considered as alternatives tools to evaluate new processing techniques in different areas of electrophysiology.

  6. EMG-based pattern recognition approach in post stroke robot-aided rehabilitation: a feasibility study

    Science.gov (United States)

    2013-01-01

    Background Several studies investigating the use of electromyographic (EMG) signals in robot-based stroke neuro-rehabilitation to enhance functional recovery. Here we explored whether a classical EMG-based patterns recognition approach could be employed to predict patients’ intentions while attempting to generate goal-directed movements in the horizontal plane. Methods Nine right-handed healthy subjects and seven right-handed stroke survivors performed reaching movements in the horizontal plane. EMG signals were recorded and used to identify the intended motion direction of the subjects. To this aim, a standard pattern recognition algorithm (i.e., Support Vector Machine, SVM) was used. Different tests were carried out to understand the role of the inter- and intra-subjects’ variability in affecting classifier accuracy. Abnormal muscular spatial patterns generating misclassification were evaluated by means of an assessment index calculated from the results achieved with the PCA, i.e., the so-called Coefficient of Expressiveness (CoE). Results Processing the EMG signals of the healthy subjects, in most of the cases we were able to build a static functional map of the EMG activation patterns for point-to-point reaching movements on the horizontal plane. On the contrary, when processing the EMG signals of the pathological subjects a good classification was not possible. In particular, patients’ aimed movement direction was not predictable with sufficient accuracy either when using the general map extracted from data of normal subjects and when tuning the classifier on the EMG signals recorded from each patient. Conclusions The experimental findings herein reported show that the use of EMG patterns recognition approach might not be practical to decode movement intention in subjects with neurological injury such as stroke. Rather than estimate motion from EMGs, future scenarios should encourage the utilization of these signals to detect and interpret the normal and

  7. Origin of the low-level EMG during the silent period following transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Butler, Jane E; Petersen, Nicolas C; Herbert, Robert D

    2012-01-01

    OBJECTIVE: The cortical silent period refers to a period of near silence in the electromyogram (EMG) after transcranial magnetic stimulation (TMS) of the motor cortex during contraction. However, low-level EMG of unknown origin is often present. We hypothesised that it arises through spinal...... the motor cortex. The rate of flexion during shortening contractions reduced muscle lengthening caused by muscle relaxation. Surface EMG was recorded from biceps brachii and brachioradialis, and the low-level EMG during silent periods produced by TMS was measured. RESULTS: Low-level EMG activity was reduced...

  8. What is slumped sitting? A kinematic and electromyographical evaluation.

    Science.gov (United States)

    Nairn, Brian C; Chisholm, Stewart R; Drake, Janessa D M

    2013-12-01

    Slumped sitting is a commonly used reference posture when comparing effects of upright sitting in both clinical and non-clinical populations alike. The exact nature of slumped sitting has not been clearly defined, including regional differences within the posture, and how the passive nature of slumped sitting compares to an active-flexion posture. Kinematic and electromyographical (EMG) data were collected from 12 males during three repeats of slumped sitting and seated maximum forward flexion. Spine angles were defined in four regions (three thoracic and lumbar) as well as for the pelvis, and EMG was collected from eight muscles bilaterally. Kinematic data were expressed as a range of motion (in degrees), and as a percent of full forward flexion while seated (%SIT-FF) and standing (%STAND-FF). EMG data were normalized to a percent maximum contraction (%MVC). Results showed that slumped sitting is characterized by 10° posterior pelvis rotation, near end-range flexion of the mid- (90%SIT-FF) and lower- (81%SIT-FF) thoracic regions, and mid-range flexion of the upper-thoracic (51%SIT-FF) and lumbar (43%SIT-FF) regions. Comparison of slumped by %STAND-FF showed the upper- and mid-thoracic regions to have high variability and large values (over 100%STAND-FF). Muscle activation showed a significant 3%MVC reduction in the lower-thoracic erector spinae muscle when moving from upright to slumped sitting. These data highlight the postural differences occurring within different spine regions, and interpretations that could be drawn, depending on which normalization (sit or stand) method is used. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Deep bite: a case report with chewing pattern and electromyographic activity before and after therapy with function generating bite.

    Science.gov (United States)

    Piancino, M G; Vallelonga, T; Debernardi, C; Bracco, P

    2013-06-01

    The purpose of this case report is the concurrent evaluation of the masticatory pattern and the electromyographic activity, recorded during mastication, before and after therapy of deep bite malocclusion. An 11-year-old boy, affected by deep bite (overbite = 5 mm) was treated by the use of a functional appliance (Function Generating Bite for Deep bite correction = FGB-D). Mandibular movements during mastication of a soft and a hard bolus were recorded both before and 10 months after correction of the malocclusion. Electromyographic activity (EMG) of the masseters and anterior temporalis muscles were recorded at the same time. Chewing cycles and EMG activity were recorded with the K7 I kinesiograph (Myotronics Inc., Seattle, WA-USA). Before therapy a higher EMG activity was recorded for both masseters and anterior temporalis muscles in comparison with the results after therapy. The results showed a great decrease of the EMG activity of masseter and anterior temporalis muscles. Moreover, the height and width of the chewing cycles in the frontal plane increased after therapy. The functional improvement showed after therapy with FGB-D showed that the functional appliance is able to correct the dental malocclusion and the masticatory function. The orthodontic treatment should consider not only the repositioning of teeth within the dental arches but also the effects on function, especially when the malocclusion involves the muscular and skeletal structures.

  10. Muscular activity of lower limb muscles associated with working on inclined surfaces.

    Science.gov (United States)

    Lu, Ming-Lun; Kincl, Laurel; Lowe, Brian; Succop, Paul; Bhattacharya, Amit

    2015-01-01

    This study investigated the effects of visual cues, muscular fatigue, task performance and experience of working on inclined surfaces on activity of postural muscles in the lower limbs associated with maintaining balance on three inclined surfaces - 0°, 14° and 26°. Normalised electromyographic (NEMG) data were collected in 44 professional roofers bilaterally from the rectus femoris, biceps femoris, tibialii anterior and gastrocnemii medial muscle groups. The 50th and 95th percentile NEMG amplitudes were used as EMG variables. Results showed that inclination angle and task performance caused a significant increase in the NEMG amplitudes of all postural muscles. Visual cues were significantly associated with a decrease in the 95th percentile EMG amplitude for the right gastrocnemius medial and tibialis anterior. Fatigue was related to a significant decrease in the NEMG amplitude for the rectus femoris. Experience of working on inclined surfaces did not have a significant effect on the NEMG amplitude.

  11. The impact of subacromial impingement syndrome on muscle activity patterns of the shoulder complex: a systematic review of electromyographic studies

    Directory of Open Access Journals (Sweden)

    Smith Toby O

    2010-03-01

    Full Text Available Abstract Background Subacromial impingement syndrome (SIS is a commonly reported cause of shoulder pain. The purpose of this study was to systematically review the literature to examine whether a difference in electromyographic (EMG activity of the shoulder complex exists between people with SIS and healthy controls. Methods Medline, CINAHL, AMED, EMBASE, and grey literature databases were searched from their inception to November 2008. Inclusion, data extraction and trial quality were assessed in duplicate. Results Nine studies documented in eleven papers, eight comparing EMG intensity and three comparing EMG onset timing, representing 141 people with SIS and 138 controls were included. Between one and five studies investigated each muscle totalling between 20 and 182 participants. The two highest quality studies of five report a significant increase in EMG intensity in upper trapezius during scaption in subjects with SIS. There was evidence from 2 studies of a delayed activation of lower trapezius in patients with SIS. There was otherwise no evidence of a consistent difference in EMG activity between the shoulders of subjects with painful SIS and healthy controls. Conclusions A difference may exist in EMG activity within some muscles, in particular upper and lower trapezius, between people with SIS and healthy controls. These muscles may be targets for clinical interventions aiding rehabilitation for people with SIS. These differences should be investigated in a larger, high quality survey and the effects of therapeutically targeting these muscles in a randomised controlled trial.

  12. Electromyographic quantification of hand performance during simulated extravehicular activity

    Science.gov (United States)

    Ranniger, Claudia Ute

    Pressure-suited humans are the most versatile work system in the space environment. Improvements in extravehicular activity (EVA) technology strive to enhance performance of manual tasks on orbit; however, methods with which to quantitatively assess these improvements are rare. This research encompasses the development of a system which can be used to quantify gloved hand performance during end-to-end EVA tasks, based both on hand motion and muscle activity. The system is unique in that it incorporates the physiological characteristics of the hand and forearm within the pressure suit glove, rather than simply evaluating the glove alone. Tracking of electromyographic (EMG) activity in the large flexor and extensor muscles of the hand, and of finger deflection within the glove, enables examination of both muscle activity levels and fatigue throughout a task. Two metrics suited to analysis of realistic, dynamic activities have been developed. A Task Intensity metric based on the amplitude distribution of the EMG signal provides a measure of the muscular effort required to complete individual activities. A mean power frequency (MPF) analysis tool derived from wavelet theory provides EMG spectral information indicative of muscle fatigue. The wavelet-based frequency analysis method is superior to traditional Fourier-based methods because it inherently provides temporal resolution of the signal, enabling decomposition of dynamic (nonstationary) and isometric (stationary) EMG signals alike. The Task Intensity and wavelet MPF analysis tools have been used to assess the gloved hand performance during representative EVA tasks completed in the suited neutral buoyancy environment, and to assess changes in muscle use during trials of a new power-assisted EVA glove. Results suggest that the metrics developed herein can be used to rank tasks based on relative muscular effort and fatigue, and that the scope of the results is naturally limited to the muscles under investigation

  13. Are fatigue-related EMG-parameters correlated to trunk extensor muscles fatigue induced by the Sörensen test?

    OpenAIRE

    Demoulin Christophe; George, Florian; Matheve, Thomas; Jidovtseff, Boris; Vanderthommen, Marc

    2016-01-01

    The Sorensen test has been extensively studied and is a rapid, simple, and reproducible evaluation of the trunk extensor muscles [1]. It is often considered as a fatigue test because fatigue-related electromyographic (EMG) parameters change throughout the test [2]; however, only recently it has been confirmed that this test induces a decrease of trunk extensor force during a maximal voluntary contraction (MVC) [3], which best characterises muscle fatigue. The main aim of this stud...

  14. An electromyographic analysis of commercial and common abdominal exercises: implications for rehabilitation and training.

    Science.gov (United States)

    Escamilla, Rafael F; McTaggart, Michael S C; Fricklas, Ethan J; DeWitt, Ryan; Kelleher, Peter; Taylor, Marcus K; Hreljac, Alan; Moorman, Claude T

    2006-02-01

    A repeated-measures, counterbalanced design. To test the effectiveness of 7 commercial abdominal machines (Ab Slide, Ab Twister, Ab Rocker, Ab Roller, Ab Doer, Torso Track, SAM) and 2 common abdominal exercises (crunch, bent-knee sit-up) on activating abdominal and extraneous (nonabdominal) musculature. Numerous abdominal machine exercises are believed to be effective in activating abdominal musculature and minimizing low back stress, but there are minimal data to substantiate these claims. Many of these exercises also activate nonabdominal musculature, which may or may not be beneficial. A convenience sample of 14 subjects performed 5 repetitions for each exercise. Electromyographic (EMG) data were recorded for upper and lower rectus abdominis, external and internal oblique, pectoralis major, triceps brachii, latissimus dorsi, lumbar paraspinals, and rectus femoris, and then normalized by maximum muscle contractions. Upper and lower rectus abdominis EMG activities were greatest for the Ab Slide, Torso Track, crunch, and Ab Roller, while external and internal oblique EMG activities were greatest for the Ab Slide, Torso Track, crunch, and bent-knee sit-up. Pectoralis major, triceps brachii, and latissimus dorsi EMG activities were greatest for the Ab Slide and Torso Track. Lumbar paraspinal EMG activities were greatest for the Ab Doer, while rectus femoris EMG activities were greatest for the bent-knee sit-up, SAM, Ab Twister, Ab Rocker, and Ab Doer. The Ab Slide and Torso Track were the most effective exercises in activating abdominal and upper extremity muscles while minimizing low back and rectus femoris (hip flexion) activity. The Ab Doer, Ab Twister, Ab Rocker, SAM, and bent-knee sit-up may be problematic for individuals with low back pathologies due to relatively high rectus femoris activity.

  15. Automated real-time detection of tonic-clonic seizures using a wearable EMG device

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Conradsen, Isa; Henning, Oliver

    2018-01-01

    OBJECTIVE: To determine the accuracy of automated detection of generalized tonic-clonic seizures (GTCS) using a wearable surface EMG device. METHODS: We prospectively tested the technical performance and diagnostic accuracy of real-time seizure detection using a wearable surface EMG device. The s...

  16. EMG analysis of back muscles during various types of sitting position

    OpenAIRE

    Nitka, Radek

    2009-01-01

    Title: EMG Analysis of Back Muscles during various Types of Sitting Position Purposes: The purpose of the thesis is the assessment of EMG activity of back muscles while sitting on a chair without any back support, and while sitting on a gymball. Methods: Surface electromyography - recording EMG activity of back muscles (20 minutes sitting on a chair and 20 minutes sitting on a gymball). Results: The mean muscle activity of all probands while sitting on a chair is higher than while sitting on ...

  17. The influence of foot position on lower leg muscle activity during a heel raise exercise measured with fine-wire and surface EMG.

    Science.gov (United States)

    Akuzawa, Hiroshi; Imai, Atsushi; Iizuka, Satoshi; Matsunaga, Naoto; Kaneoka, Koji

    2017-11-01

    Exercises for lower leg muscles are important to improve function. To examine the influence of foot position on lower leg muscle activity during heel raises. Cross-sectional laboratory study. Laboratory. Fourteen healthy men participated in this study. The muscle activity levels of the tibialis posterior (TP), peroneus longus (PL), flexor digitorum longus (FDL) and medial gastrocnemius (MG) were measured. The heel raises consisted of three foot positions: 1) neutral, 2) 30° abduction, and 3) 30° adduction. The EMG data for five repetitions of each foot position were normalized to maximum voluntary contraction. One-way repeated measure ANOVA was employed for statistical analysis. The muscle activity level of TP, PL and FDL was significantly different between the three foot positions during the heel raises. TP and FDL showed the highest activity level in 30° foot adduction while PL demonstrated the highest activity level in 30° foot abduction. Heel raises with 30° foot adduction and abduction positions can change lower leg muscle activity; These findings suggest that altering foot posture during the heel raise exercise may benefit patients with impaired TP, PL or FDL function. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Electromyographic Findings in Overt Hypothyroidism and Subclinical Hypothyroidism

    Directory of Open Access Journals (Sweden)

    Emel Oğuz Akarsu

    2013-12-01

    Full Text Available OBJECTIVE: Hypothyroidism may cause neurologic signs and symptoms as its effects neuromuscular system like many other systems. Subclinical hypothyroidism is the most common thyroid dysfuntion, it may cause neuromuscular signs and symptoms. In this retrospective study, it is aimed to compare neuromuscular symptoms and electromyographic (EMG manifestations between hypothyroid patients and control group with normal thyroid function and without a disease causing polyneuropathy. METHODS: 31 overt hypothyroidic, 139 subclinic hypothyroidic patients and 50 individuals with normal thyroid function, without a disease causing polyneuropathy, as control group whom made EMG for another reason were included to the study. Neuromuscular symptoms, neurological examination and electrophysiological findings was obtained from the patient records. RESULTS: In our study, we observed frequent neuromuscular complaints such as fatigue, morning stiffness, cramp, general pain and paresthesia in favor of both for overt and subclinic hypothyroidism. Carpal Tunnel Syndrom(CTS, was statistically higher in overt hypothyroidism group than control group. CTS was also observed higher in subclinic hypothyroidism group when compared with control group but it didn't reach to statistical significance. We did not detect polyneuropathy in any group. Motor nerve velocity and compound muscle action potential amplitudes were found to be statistically significant difference between hypothyroid ve control group. CONCLUSION: Since motor fibres' and neuromuscular area's being affected in hypothyroidism, which we interpret to happen due to basal metabolism's slowing down, can show a significant recovery after thyroid replacement therapy. We consider that, in further studies, comparison of electrophysiological findings after treatment with the findings of pre -treatment is necessary

  19. Comparative Analysis of Wavelet-based Feature Extraction for Intramuscular EMG Signal Decomposition.

    Science.gov (United States)

    Ghofrani Jahromi, M; Parsaei, H; Zamani, A; Dehbozorgi, M

    2017-12-01

    Electromyographic (EMG) signal decomposition is the process by which an EMG signal is decomposed into its constituent motor unit potential trains (MUPTs). A major step in EMG decomposition is feature extraction in which each detected motor unit potential (MUP) is represented by a feature vector. As with any other pattern recognition system, feature extraction has a significant impact on the performance of a decomposition system. EMG decomposition has been studied well and several systems were proposed, but feature extraction step has not been investigated in detail. Several EMG signals were generated using a physiologically-based EMG signal simulation algorithm. For each signal, the firing patterns of motor units (MUs) provided by the simulator were used to extract MUPs of each MU. For feature extraction, different wavelet families including Daubechies (db), Symlets, Coiflets, bi-orthogonal, reverse bi-orthogonal and discrete Meyer were investigated. Moreover, the possibility of reducing the dimensionality of MUP feature vector is explored in this work. The MUPs represented using wavelet-domain features are transformed into a new coordinate system using Principal Component Analysis (PCA). The features were evaluated regarding their capability in discriminating MUPs of individual MUs. Extensive studies on different mother wavelet functions revealed that db2, coif1, sym5, bior2.2, bior4.4, and rbior2.2 are the best ones in differentiating MUPs of different MUs. The best results were achieved at the 4th detail coefficient. Overall, rbior2.2 outperformed all wavelet functions studied; nevertheless for EMG signals composed of more than 12 MUPTs, syms5 wavelet function is the best function. Applying PCA slightly enhanced the results.

  20. Quantifying the effects of electrode distance from the innervation zone on the electromyographic amplitude versus torque relationships

    International Nuclear Information System (INIS)

    Herda, Trent J; Weir, Joseph P; Zuniga, Jorge M; Ryan, Eric D; Camic, Clayton L.; Bergstrom, Haley C; Cramer, Joel T; Housh, Terry J; Smith, Doug B

    2013-01-01

    The present study applied a log-transformation model to compare the electromyographic (EMG) amplitude versus torque relationships from monopolar EMG signals up to 35 mm proximal and distal from the innervation zone (IZ). Seven men (age = 23 ± 2 year; mass = 82 ± 10 kg) and two women (age = 21 ± 1 year; mass = 62 ± 8 kg) performed isometric ramp contractions of the right leg extensors with an eight-channel linear electrode array positioned over the vastus lateralis with the IZ located between channels 4 and 5. Linear regression models were fit to the log-transformed monopolar EMG RMS –torque relationships with the b terms (slope) and the a terms (Y-intercept) calculated for each channel and subject. The b terms for channels 4, 5, and 6 were higher (P ≤ 0.05) than the more distal channels 7 and 8 (P < 0.05). In contrast, there were no differences (P > 0.05) among the a terms of the eight channels. Thus, the shapes of the monopolar EMG RMS –torque relationships were altered as a function of distance between the IZ and recording area, which may be helpful for clinicians and researchers who infer changes in motor control strategies based on the shapes of the EMG RMS –torque relationships. (paper)

  1. Effect of shoe heel height on vastus medialis and vastus lateralis electromyographic activity during sit to stand

    Directory of Open Access Journals (Sweden)

    Hodgson David

    2008-01-01

    Full Text Available Abstract Background It has been proposed that high-heeled shoes may contribute to the development and progression of knee pain. However, surprisingly little research has been carried out on how shoe heel height affects muscle activity around the knee joint. The purpose of this study was to investigate the effect of differing heel height on the electromyographic (EMG activity in vastus medialis (VM and vastus lateralis (VL during a sit to stand activity. This was an exploratory study to inform future research. Methods A repeated measures design was used. Twenty five healthy females carried out a standardised sit to stand activity under 4 conditions; barefoot, and with heel wedges of 1, 3, and 5 cm in height. EMG activity was recorded from VM and VL during the activity. Data were analysed using 1 × 4 repeated measures ANOVA. Results Average rectified EMG activity differed with heel height in both VM (F2.2, 51.7 = 5.24, p 3, 72 = 5.32, p 3, 72 = 0.61, p = 0.609. Conclusion We found that as heel height increased, there was an increase in EMG activity in both VM and VL, but no change in the relative EMG intensity of VM and VL as measured by the VM: VL ratio. This showed that no VM: VL imbalance was elicited. This study provides information that will inform future research on how heel height affects muscle activity around the knee joint.

  2. Electromyographic investigation of unstable patella before and after its realignment operation

    Directory of Open Access Journals (Sweden)

    D D Baksi

    2011-01-01

    Full Text Available Background: Patellar dislocations are either due to superolateral contracture of the soft tissue or imbalance of the power between the vastus medialis (VM and the vastus lateralis (VL. The imbalance of muscle power as an etiology of patellar dislocation has not been studied. Hence, we studied the recurrent, habitual and permanent dislocations of the patella with an electromyogram (EMG of the vastus medialis, vastus lateralis, and pes anserinus, before and after realignment operations, to document the muscle imbalance and effectiveness of the realignment operation. Materials and Methods: An electromyographic investigation was carried out on the vastus medialis and vastus lateralis in nine recurrent, 20 habitual, and 13 permanent dislocations of the patella, before and after their realignment operations. Pes anserinus transposition, which acted as a medial stabilizer of the patella, was also investigated with an EMG study, to understand its role on patellar stability at 0΀, 30΀, 60΀, 90΀, 120΀, 150΀, and full flexion of the knee. The age of the patients varied from nine to 30 (mean 15 years. There were 24 males and 18 females. Twenty-six patellar dislocations were on the right and 16 were on the left side. Results: Electromyographic pictures reveal subnormal activity of the vastus medialis in all types of dislocations and similar activities of the vastus lateralis in permanent and habitual dislocations recorded pre operatively, which recovered to almost normal values postoperatively, at the mean one-year follow-up. Pes anserinus, which was used for medial stabilization of the patella after its realignment, maintained normal EMG activity before and after the operation. Conclusion: This study is significant for understanding the imbalance of muscle activities in patients with an unstable patella, which can be rectified without recurrence after pes anserinus transposition.

  3. Locomotor training with body weight support in SCI: EMG improvement is more optimally expressed at a low testing speed.

    Science.gov (United States)

    Meyns, P; Van de Crommert, H W A A; Rijken, H; van Kuppevelt, D H J M; Duysens, J

    2014-12-01

    Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) was assessed in four leg muscles; biceps femoris, rectus femoris, gastrocnemius medialis and tibialis anterior. The changes in RMS EMG occurred at similar phases of the step cycle for both walking conditions, but these changes were larger when the treadmill was set at a low speed (0.5 km h(-1)). Improvement in gait is feasible with BWS treadmill training even long after injury. The EMG changes after treadmill training are more optimally expressed using a low rather than a high testing treadmill speed.

  4. Comparison of algorithms to quantify muscle fatigue in upper limb muscles based on sEMG signals.

    Science.gov (United States)

    Kahl, Lorenz; Hofmann, Ulrich G

    2016-11-01

    This work compared the performance of six different fatigue detection algorithms quantifying muscle fatigue based on electromyographic signals. Surface electromyography (sEMG) was obtained by an experiment from upper arm contractions at three different load levels from twelve volunteers. Fatigue detection algorithms mean frequency (MNF), spectral moments ratio (SMR), the wavelet method WIRM1551, sample entropy (SampEn), fuzzy approximate entropy (fApEn) and recurrence quantification analysis (RQA%DET) were calculated. The resulting fatigue signals were compared considering the disturbances incorporated in fatiguing situations as well as according to the possibility to differentiate the load levels based on the fatigue signals. Furthermore we investigated the influence of the electrode locations on the fatigue detection quality and whether an optimized channel set is reasonable. The results of the MNF, SMR, WIRM1551 and fApEn algorithms fell close together. Due to the small amount of subjects in this study significant differences could not be found. In terms of disturbances the SMR algorithm showed a slight tendency to out-perform the others. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Differences in the EMG pattern of lea muscle activation during locomotion in Parkinson's disease

    NARCIS (Netherlands)

    Albani, G; Sandrini, G; Kunig, G; Martin-Soelch, C; Mauro, A; Pignatti, R; Pacchetti, C; Dietz, [No Value; Leenders, KL

    2003-01-01

    In this pilot study, EMG patterns of leg muscle activation were studied in five parkinsonian patients with (B1) and five without (B2) freezing. Gastrocnemius medialis (GM) and tibialis anterior (TA) activity was analysed, by means of surface electromyography (EMG), during treadmill walking at two

  6. Therapeutic efficacy of neuromuscular electrical stimulation and electromyographic biofeedback on Alzheimer's disease patients with dysphagia.

    Science.gov (United States)

    Tang, Yi; Lin, Xiang; Lin, Xiao-Juan; Zheng, Wei; Zheng, Zhi-Kai; Lin, Zhao-Min; Chen, Jian-Hao

    2017-09-01

    To study the therapeutic effect of neuromuscular electrical stimulation and electromyographic biofeedback (EMG-biofeedback) therapy in improving swallowing function of Alzheimer's disease patients with dysphagia.A series of 103 Alzheimer's disease patients with dysphagia were divided into 2 groups, among which the control group (n = 50) received swallowing function training and the treatment group (n = 53) received neuromuscular electrical stimulation plus EMG-biofeedback therapy. The mini-mental state scale score was performed in all patients along the treatment period. Twelve weeks after the treatment, the swallowing function was assessed by the water swallow test. The nutritional status was evaluated by Mini Nutritional Assessment (MNA) as well as the levels of hemoglobin and serum albumin. The frequency and course of aspiration pneumonia were also recorded.No significant difference on mini-mental state scale score was noted between 2 groups. More improvement of swallowing function, better nutritional status, and less frequency and shorter course of aspiration pneumonia were presented in treatment group when compared with the control group.Neuromuscular electrical stimulation and EMG-biofeedback treatment can improve swallowing function in patients with Alzheimer's disease and significantly reduce the incidence of adverse outcomes. Thus, they should be promoted in clinical practice.

  7. Electromyographical comparison of plank variations performed with and without instability devices.

    Science.gov (United States)

    Snarr, Ronald L; Esco, Michael R

    2014-11-01

    Although there are multiple studies involving abdominal musculature activation and instability devices (e.g., Swiss balls), there is minimal research comparing them with a suspension device (e.g., TRX). The purpose of this investigation was to measure the electromyographical (EMG) activity of the rectus abdominis (RA), external oblique (EO), and erector spinae while performing planks with and without multiple instability devices. Twelve apparently healthy men (n = 6; age = 23.92 ± 3.64 years) and women (n = 6; age = 22.57 ± 1.87 years) volunteered to participate in this study. All participants performed 2 isometric contractions of 5 different plank variations, with or without an instability device, where the order of the exercises was randomized. Mean peak and normalized EMG of the RA, EO, and erector spinae musculature were compared across the 5 exercises. Results indicated that planks performed with the instability devices increased EMG activity in the superficial musculature when compared with traditional stable planks. Therefore, a traditional plank performed on a labile device may be considered an advanced variation and appropriate for use when a greater challenge is warranted. However, caution should be taken for those individuals with a history or weakness in the lumbar region due to the increases in erector spinae activation during instability planks.

  8. Effect of Selective Muscle Training Using Visual Emg Biofeedback on Infraspinatus and Posterior Deltoid

    Directory of Open Access Journals (Sweden)

    Lim One-bin

    2014-12-01

    Full Text Available We investigated the effects of visual electromyography (EMG biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity.

  9. Effect of Selective Muscle Training Using Visual EMG Biofeedback on Infraspinatus and Posterior Deltoid

    Science.gov (United States)

    Lim, One-bin; Kim, Jeong-ah; Song, Si-jeong; Cynn, Heon-seock; Yi, Chung-hwi

    2014-01-01

    We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity. PMID:25713668

  10. EMG of the hip adductor muscles in six clinical examination tests.

    Science.gov (United States)

    Lovell, Gregory A; Blanch, Peter D; Barnes, Christopher J

    2012-08-01

    To assess activation of muscles of hip adduction using EMG and force analysis during standard clinical tests, and compare athletes with and without a prior history of groin pain. Controlled laboratory study. 21 male athletes from an elite junior soccer program. Bilateral surface EMG recordings of the adductor magnus, adductor longus, gracilis and pectineus as well as a unilateral fine-wire EMG of the pectineus were made during isometric holds in six clinical examination tests. A load cell was used to measure force data. Test type was a significant factor in the EMG output for all four muscles (all muscles p magnus, adductor longus and gracilis. EMG activation for pectineus was highest in Hips 90. Injury history was a significant factor in the EMG output for the adductor longus (p magnus. For force data, clinical test type was a significant factor (p force. All other factors had no significant effect on the force outputs. Hip adduction strength assessment is best measured at hips 0 (which produced most force) or 45° flexion (which generally gave the highest EMG output). Muscle EMG varied significantly with clinical test position. Athletes with previous groin injury had a significant fall in some EMG outputs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. EMG activities and plantar pressures during ski jumping take-off on three different sized hills.

    Science.gov (United States)

    Virmavirta, M; Perttunen, J; Komi, P V

    2001-04-01

    Different profiles of ski jumping hills have been assumed to make the initiation of take-off difficult especially when moving from one hill to another. Neuromuscular adaptation of ski jumpers to the different jumping hills was examined by measuring muscle activation and plantar pressure of the primary take-off muscles on three different sized hills. Two young ski jumpers volunteered as subjects and they performed several trials from each hill (K-35 m, K-65 m and K-90 m) with the same electromyographic (EMG) electrode and insole pressure transducer set-up. The results showed that the differences in plantar pressure and EMGs between the jumping hills were smaller than expected for both jumpers. The small changes in EMG amplitudes between the hills support the assumption that the take-off was performed with the same intensity on different jumping hills and the timing of the gluteus EMG demonstrates well the similarity of the muscle activation on different hills. On the basis of the results obtained it seems that ski jumping training on small hills does not disturb the movement patterns for bigger hills and can also be helpful for special take-off training with low speed.

  12. Control of Leg Movements Driven by EMG Activity of Shoulder Muscles

    Science.gov (United States)

    La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P.

    2014-01-01

    During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3–5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human–machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons. PMID:25368569

  13. Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies.

    Science.gov (United States)

    Shultz, Rebecca; Silder, Amy; Malone, Maria; Braun, Hillary Jane; Dragoo, Jason Logan

    2015-03-01

    Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor (stable surface). (1) The SLD on an unstable surface would lower the quadriceps to hamstrings electromyographic (EMG) activation ratio (Q:H EMG activation ratio) compared with being performed on the floor. (2) Lower Q:H EMG activation ratio would be caused by a relative increase in hamstring activation, with no significant change in quadriceps activation. Controlled laboratory study. Thirty-nine Division I National Collegiate Athletic Association (NCAA) female athletes performed 3 SLDs per leg onto a Bosu ball and onto the floor. Muscle activity of the vastus lateralis and lateral hamstrings were used to estimate peak quadriceps and hamstring activation, along with the Q:H EMG activation ratio. Kinematic measures at the knee, hip, and trunk were also estimated. Differences between landings were assessed using a 2-level analysis of variance (limb and surface). The maximum Q:H EMG activation ratio was significantly reduced when athletes performed an SLD onto the Bosu ball (20%, P hamstring activity was higher when athletes landed on a Bosu ball (18% higher, P = 0.029) compared with when they landed on the floor. Compared with landing on the floor (a stable surface), landing on a Bosu ball (unstable surface) changed the athlete's co-contraction at the knee and increased hamstring activity. However, landing on a Bosu ball also decreased the athlete's knee flexion, which was an undesired effect. These findings highlight the potential utility of unstable surfaces as a training tool to reduce the risk of ACL injury in female athletes.

  14. Simultaneous EEG and EMG biofeedback for peak performance in musicians.

    Science.gov (United States)

    Markovska-Simoska, Silvana; Pop-Jordanova, Nada; Georgiev, Dejan

    2008-07-01

    The aim of this study was to determine the effects of alpha neurofeedback and EMG biofeedback protocols for improvement of musical performance in violinists. The sample consisted of 12 music students (10 violinists and 2 viola players) from the Faculty of Music, Skopje (3 males, mean age of 20 +/- 0 and 9 females, mean age = 20.89 +/- 2.98). Six of them had a low alpha peak frequency (APF) ( 10 Hz). The sample was randomized in two groups. The students from the experimental group participated in 20 sessions of biofeedback (alpha/EMG), combined with music practice, while the students from the control group did only music practice. Average absolute power, interhemispheric coherence in the alpha band, alpha peak frequency (APF), individual alpha band width (IABW), amount of alpha suppression (AAS) and surface forehead integrated EMG power (IEMG), as well as a score on musical performance and inventories measuring anxiety, were assessed. Alpha-EEG/EMG-biofeedback was associated with a significant increase in average alpha power, APF and IABW in all the participants and with decreases in IEMG only in high-APF musicians. The biofeedback training success was positively correlated with the alpha power, IcoH, APF, IABW and baseline level of APF and IABW. Alpha-EEG/EMG biofeedback is capable of increasing voluntary self-regulation and the quality of musical performance. The efficiency of biofeedback training depends on the baseline EEG alpha activity status, in particular the APF.

  15. Simulation of facial expressions using person-specific sEMG signals controlling a biomechanical face model.

    Science.gov (United States)

    Eskes, Merijn; Balm, Alfons J M; van Alphen, Maarten J A; Smeele, Ludi E; Stavness, Ian; van der Heijden, Ferdinand

    2018-01-01

    Functional inoperability in advanced oral cancer is difficult to assess preoperatively. To assess functions of lips and tongue, biomechanical models are required. Apart from adjusting generic models to individual anatomy, muscle activation patterns (MAPs) driving patient-specific functional movements are necessary to predict remaining functional outcome. We aim to evaluate how volunteer-specific MAPs derived from surface electromyographic (sEMG) signals control a biomechanical face model. Muscle activity of seven facial muscles in six volunteers was measured bilaterally with sEMG. A triple camera set-up recorded 3D lip movement. The generic face model in ArtiSynth was adapted to our needs. We controlled the model using the volunteer-specific MAPs. Three activation strategies were tested: activating all muscles [Formula: see text], selecting the three muscles showing highest muscle activity bilaterally [Formula: see text]-this was calculated by taking the mean of left and right muscles and then selecting the three with highest variance-and activating the muscles considered most relevant per instruction [Formula: see text], bilaterally. The model's lip movement was compared to the actual lip movement performed by the volunteers, using 3D correlation coefficients [Formula: see text]. The correlation coefficient between simulations and measurements with [Formula: see text] resulted in a median [Formula: see text] of 0.77. [Formula: see text] had a median [Formula: see text] of 0.78, whereas with [Formula: see text] the median [Formula: see text] decreased to 0.45. We demonstrated that MAPs derived from noninvasive sEMG measurements can control movement of the lips in a generic finite element face model with a median [Formula: see text] of 0.78. Ultimately, this is important to show the patient-specific residual movement using the patient's own MAPs. When the required treatment tools and personalisation techniques for geometry and anatomy become available, this may

  16. Electromyographic validation of the trapezius and serratus anterior muscles in frontal-lateral cross, dumbbells exercises.

    Science.gov (United States)

    Büll, M L; Freitas, V; Vitti, M; Rosa, G J M

    2002-01-01

    Based on the lack of electromyographic researches on sport and programmes of physical conditioning, we can say that it is necessary to reexamine some exercises routinely used in the programmes of physical conditioning. Thus, the trapezius and serratus anterior muscles were studied electromyographically so that we could evaluate the validity in some ways of execution of the frontal-lateral cross, dumbbells exercises for the development of these muscles. We analyzed 24 male volunteers, 18 to 25 years old, using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. For the execution of the exercise it was used a supine bench, a straight board and two bars of 40 cm made of light wood. The results showed that TS acted preferentially in standing modality and in the inclined supine modality, however with activity levels that do not justify its inclusion in physical fitness programmes.

  17. Effect of Electromyographic Biofeedback Training on Pain, Quadriceps Muscle Strength, and Functional Ability in Juvenile Rheumatoid Arthritis.

    Science.gov (United States)

    Eid, Mohamed Ahmed Mahmoud; Aly, Sobhy M; El-Shamy, Shamekh M

    2016-12-01

    To investigate the effects of electromyographic (EMG) biofeedback training on pain, quadriceps strength, and functional ability in juvenile rheumatoid arthritis (JRA). This is a randomized controlled study; 36 children (11 boys and 25 girls) with polyarticular JRA, with ages ranging from 8 to 13 years, were selected and assigned randomly, using computer-generated random numbers, into 2 groups. The control group (n = 18) received the conventional physical therapy program, whereas the study group (n = 18) received the same program as the control group in addition to EMG biofeedback-guided isometric exercises for 3 days a week for 12 weeks. Pain, peak torque of quadriceps strength, and functional ability were evaluated before, after 6 weeks, and at the end of 12 weeks of the treatment program. By 6 weeks, significant differences were observed in the study group (P biofeedback may be a useful intervention modality to reduce pain, improve quadriceps strength, and functional performance in JRA.

  18. Detection of EMG-based muscle fatigue during cyclic dynamic contraction using a monopolar configuration.

    Science.gov (United States)

    Hotta, Yu; Ito, Kenichi

    2013-01-01

    Measurement of surface EMG signals is usually performed using the bipolar (single differential) configuration. However, even if contraction during exercise is performed until near-complete exhaustion, the change in the surface EMG accompanying the fatigue could be undetectable using the bipolar configuration. In order to overcome this disadvantage, this study proposes the measurement of surface EMG using the monopolar configuration. Experimental results show that the monopolar configuration can detect the change in muscle fatigue with greater sensitivity and better stability, as compared to the bipolar configuration.

  19. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

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    Abdullah Serefoglu, Ufuk Sekir, Hakan Gür, Bedrettin Akova

    2017-03-01

    Full Text Available The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a non-stretching (control, (b static stretching of the quadriceps muscles, (c static stretching of the hamstring muscles, (d dynamic stretching of the quadriceps muscles, and (e dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05 differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05 following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG

  20. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles.

    Science.gov (United States)

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-03-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  1. Análise eletromiográfica e força do grupo muscular extensor do punho durante isquemia induzida Electromyographic analysis and strength of the wrist extensor muscle group during induced ischemia

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    CCA Bandeira

    2009-02-01

    procedure was repeated on three nonconsecutive days. Ischemia was induced for 5 minutes using a sphygmomanometer placed on the dominant arm and inflated until blood flow was absent, as confirmed by Doppler ultrasound. The EMG1000 module (Lynx® was used with differential surface electrodes (Lynx® to record the electromyographic signal of the WEMG. Three MVIC were recorded for 15 seconds, with 30 seconds intervals between them, under the following conditions: pre-ischemia, ischemia, immediate post-ischemia (post-1 and later post-ischemia (post-2: 10 minutes after the onset of ischemia. The MATLAB 6.5.1 software was used to analyze the parameters for the electromyographic signal, the root mean square (RMS and the median frequency of the signal power spectrum. For statistical analysis, two-way ANOVA and the Friedman test were used. RESULTS: Ischemia caused a significant reduction (p<0.05 in WEMG strength. However, there were no significant changes in the RMS electromyographic parameters (p=0.05 or the median frequency of the signal power spectrum (p=0.09. CONCLUSION: Induced ischemia caused WEMG fatigue in relation to muscle strength production. However, it did not cause electromyographic fatigue in the evaluated muscle group.

  2. Behaviour of a surface EMG based measure for motor control: Motor unit action potential rate in relation to force and muscle fatigue

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Hermens, Hermanus J.

    2008-01-01

    Surface electromyography parameters such as root-mean-square value (RMS) and median power frequency (FMED) are commonly used to assess the input of the central nervous system (CNS) to a muscle. However, RMS and FMED are influenced not only by CNS input, but also by peripheral muscle properties. The

  3. Measurement of EMG activity with textile electrodes embedded into clothing.

    Science.gov (United States)

    Finni, T; Hu, M; Kettunen, P; Vilavuo, T; Cheng, S

    2007-11-01

    Novel textile electrodes that can be embedded into sports clothing to measure averaged rectified electromyography (EMG) have been developed for easy use in field tests and in clinical settings. The purpose of this study was to evaluate the validity, reliability and feasibility of this new product to measure averaged rectified EMG. The validity was tested by comparing the signals from bipolar textile electrodes (42 cm(2)) and traditional bipolar surface electrodes (1.32 cm(2)) during bilateral isometric knee extension exercise with two electrode locations (A: both electrodes located in the same place, B: traditional electrodes placed on the individual muscles according to SENIAM, n=10 persons for each). Within-session repeatability (the coefficient of variation CV%, n=10) was calculated from five repetitions of 60% maximum voluntary contraction (MVC). The day-to-day repeatability (n=8) was assessed by measuring three different isometric force levels on five consecutive days. The feasibility of the textile electrodes in field conditions was assessed during a maximal treadmill test (n=28). Bland-Altman plots showed a good agreement within 2SD between the textile and traditional electrodes, demonstrating that the textile electrodes provide similar information on the EMG signal amplitude to the traditional electrodes. The within-session CV ranged from 13% to 21% in both the textile and traditional electrodes. The day-to-day CV was smaller, ranging from 4% to 11% for the textile electrodes. A similar relationship (r(2)=0.5) was found between muscle strength and the EMG of traditional and textile electrodes. The feasibility study showed that the textile electrode technique can potentially make EMG measurements very easy in field conditions. This study indicates that textile electrodes embedded into shorts is a valid and feasible method for assessing the average rectified value of EMG.

  4. User adaptation in long-term, open-loop myoelectric training: implications for EMG pattern recognition in prosthesis control

    Science.gov (United States)

    He, Jiayuan; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Farina, Dario; Zhu, Xiangyang

    2015-08-01

    Objective. Recent studies have reported that the classification performance of electromyographic (EMG) signals degrades over time without proper classification retraining. This problem is relevant for the applications of EMG pattern recognition in the control of active prostheses. Approach. In this study we investigated the changes in EMG classification performance over 11 consecutive days in eight able-bodied subjects and two amputees. Main results. It was observed that, when the classifier was trained on data from one day and tested on data from the following day, the classification error decreased exponentially but plateaued after four days for able-bodied subjects and six to nine days for amputees. The between-day performance became gradually closer to the corresponding within-day performance. Significance. These results indicate that the relative changes in EMG signal features over time become progressively smaller when the number of days during which the subjects perform the pre-defined motions are increased. The performance of the motor tasks is thus more consistent over time, resulting in more repeatable EMG patterns, even if the subjects do not have any external feedback on their performance. The learning curves for both able-bodied subjects and subjects with limb deficiencies could be modeled as an exponential function. These results provide important insights into the user adaptation characteristics during practical long-term myoelectric control applications, with implications for the design of an adaptive pattern recognition system.

  5. Differential EMG biofeedback for children with ADHD: a control method for neurofeedback training with a case illustration.

    Science.gov (United States)

    Maurizio, S; Liechti, M D; Brandeis, D; Jäncke, L; Drechsler, R

    2013-06-01

    The objective of the present paper was to develop a differential electromyographic biofeedback (EMG-BF) training for children with attention-deficit/hyperactivity disorder (ADHD) matching multiple neurofeedback training protocols in order to serve as a valid control training. This differential EMG-BF training method feeds back activity from arm muscles involved in fine motor skills such as writing and grip force control. Tonic EMG-BF training (activation and deactivation blocks, involving bimanual motor tasks) matches the training of EEG frequency bands, while phasic EMG-BF training (short activation and deactivation trials) was developed as an equivalent to the training of slow cortical potentials. A case description of a child who learned to improve motor regulation in most task conditions and showed a clinically relevant reduction of behavioral ADHD symptoms illustrates the training course and outcome. Differential EMG-BF training is feasible and provides well-matched control conditions for neurofeedback training in ADHD research. Future studies should investigate its value as a specific intervention for children diagnosed with ADHD and comorbid sensorimotor problems.

  6. EMG processing to interpret a neural tension-limiting mechanism with fatigue.

    Science.gov (United States)

    La Delfa, Nicholas J; Sutherland, Chad A; Potvin, Jim R

    2014-09-01

    Surface electromyography (sEMG) amplitude increases with constant muscle tension during fatiguing sub-maximum efforts. The purpose of this study was to determine if extreme highpass filtering and/or autoregressive whitening would result in a more consistent sEMG-to-moment ratio than a standard bandpass filter (20-500 Hz) during repeated, dynamic maximal efforts of the quadriceps. We collected sEMG and knee extensor moment from 16 participants during the concentric and eccentric phases of repeated, maximal knee extensor efforts. The alternative processing methods provided more consistent vastus medialis and lateralis sEMG-to-moment ratios. A neural tension-limiting mechanism appeared to exist and was magnified during the eccentric phase, particularly with fatigue. There appears to be a difference in how the central nervous system controls concentric and eccentric efforts as the quadriceps fatigues, and this is more apparent with the alternative EMG processing methods we used. Copyright © 2013 Wiley Periodicals, Inc.

  7. Recognition of grasp types through principal components of DWT based EMG features.

    Science.gov (United States)

    Kakoty, Nayan M; Hazarika, Shyamanta M

    2011-01-01

    With the advancement in machine learning and signal processing techniques, electromyogram (EMG) signals have increasingly gained importance in man-machine interaction. Multifingered hand prostheses using surface EMG for control has appeared in the market. However, EMG based control is still rudimentary, being limited to a few hand postures based on higher number of EMG channels. Moreover, control is non-intuitive, in the sense that the user is required to learn to associate muscle remnants actions to unrelated posture of the prosthesis. Herein lies the promise of a low channel EMG based grasp classification architecture for development of an embedded intelligent prosthetic controller. This paper reports classification of six grasp types used during 70% of daily living activities based on two channel forearm EMG. A feature vector through principal component analysis of discrete wavelet transform coefficients based features of the EMG signal is derived. Classification is through radial basis function kernel based support vector machine following preprocessing and maximum voluntary contraction normalization of EMG signals. 10-fold cross validation is done. We have achieved an average recognition rate of 97.5%. © 2011 IEEE

  8. Analysis of the sEMG/force relationship using HD-sEMG technique and data fusion: A simulation study.

    Science.gov (United States)

    Al Harrach, Mariam; Carriou, Vincent; Boudaoud, Sofiane; Laforet, Jeremy; Marin, Frederic

    2017-04-01

    The relationship between the surface Electromyogram (sEMG) signal and the force of an individual muscle is still ambiguous due to the complexity of experimental evaluation. However, understanding this relationship should be useful for the assessment of neuromuscular system in healthy and pathological contexts. In this study, we present a global investigation of the factors governing the shape of this relationship. Accordingly, we conducted a focused sensitivity analysis of the sEMG/force relationship form with respect to neural, functional and physiological parameters variation. For this purpose, we used a fast generation cylindrical model for the simulation of an 8×8 High Density-sEMG (HD-sEMG) grid and a twitch based force model for the muscle force generation. The HD-sEMG signals as well as the corresponding force signals were simulated in isometric non-fatiguing conditions and were based on the Biceps Brachii (BB) muscle properties. A total of 10 isometric constant contractions of 5s were simulated for each configuration of parameters. The Root Mean Squared (RMS) value was computed in order to quantify the sEMG amplitude. Then, an image segmentation method was used for data fusion of the 8×8 RMS maps. In addition, a comparative study between recent modeling propositions and the model proposed in this study is presented. The evaluation was made by computing the Normalized Root Mean Squared Error (NRMSE) of their fitting to the simulated relationship functions. Our results indicated that the relationship between the RMS (mV) and muscle force (N) can be modeled using a 3rd degree polynomial equation. Moreover, it appears that the obtained coefficients are patient-specific and dependent on physiological, anatomical and neural parameters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Muscle fiber conduction velocity and EMG amplitude of the upper trapezius muscle in healthy subjects after low-level laser irradiation: a randomized, double-blind, placebo-controlled, crossover study.

    Science.gov (United States)

    Sarilho de Mendonça, Fabiana; de Tarso Camillo de Carvalho, Paulo; Biasotto-Gonzalez, Daniela Aparecida; Calamita, Simone Aparecida Penimpedo; de Paula Gomes, Cid André Fidelis; Amorim, César Ferreira; Fumagalli, Marco Antônio; Politti, Fabiano

    2017-12-05

    Although low-level laser therapy (LLLT) is an important resource for the treatment of non-specific neck pain patients, the dose which presents the greatest therapeutic potential for the treatment of this pathology is still unclear. The present study aimed to evaluate the immediate effect of LLLT on the muscle fiber conduction velocity (MFCV) and electromyographic activity (EMG) of the upper trapezius (UT) muscle in healthy individuals. A total of 20 healthy subjects were enrolled in a randomized, double-blind, crossover study. Active LLLT (820 nm wavelength, 30 mW, energy total 18 J) or placebo LLLT (pLLLT) was delivered on the UT muscle. Each subject was subjected to a single session of active LLLT and pLLLT. Surface electromyography (sEMG) signal of the UT muscle was recorded during five different step contractions of shoulder elevation force (10-30% maximal voluntary contraction) pre- and post-LLLT irradiation. The values of MFCV and sEMG global amplitude (RMS G ) were used to calculate the effects of LLLT. The results showed no difference in the MFCV comparing the LLLT and pLLLT groups (F = 0.72 p = 0.39, η p 2  = 0.004). However, a significant difference was observed in the RMS G between the LLLT and pLLLT (F 1,2  = 16.66; P upper trapezius muscle in healthy subjects to a level of up to 30% of maximal voluntary contraction.

  10. Influência do calçado de salto alto na atividade eletromiográfica do músculo quadríceps em mulheres com e sem síndrome da dor femoropatelar durante a tarefa de levantar e sentar Influencia del calzado de tacón alto en la actividad electromiográfica del músculo cuádriceps en mujeres con y sin síndrome de dolor patelofemoral durante la tarea de levantarse y sentarse Influence of high-heeled shoes on the quadriceps electromyographic activity in women with and without patellofemoral pain syndrome during the sit-to-stand task

    Directory of Open Access Journals (Sweden)

    Laísla da Silva Paixão Batista

    2013-03-01

    performed a standardized sit-to-stand task under 3 conditions: barefoot, wearing sneakers and wearing 10 cm high-heeled shoes. The electromyographic (EMG activity was recorded from the vastus medialis obliquus (VMO, vastus lateralis (VL and rectus femoris (RF muscles during the tasks using simple differential surface electrodes connected to an EMG system. To compare data between groups and tasks, the ANOVA test with repeated measures and the Tukey post hoc test were applied (p<0.05. Results demonstrated higher EMG activity for the VMO muscles during stand and sit tasks performed with high-heeled shoes in the control group. In the PFPS group, an increased EMG activity for the VL muscle during the stand task was observed, and the VMO:VL ratio decreased with the use of high heels. Results show that the use of high-heeled shoes can further increase the EMG activity of the VL muscle than the VMO in women with PFPS, a fact that may contribute to the increased joint imbalance and worsened PFPS. Therefore, the results suggest that this type of footwear should be avoided by women with PFPS.

  11. The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Morufu Olusola Ibitoye

    2014-07-01

    Full Text Available The evoked electromyographic signal (eEMG potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05 between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI population.

  12. An EMG-driven biomechanical model that accounts for the decrease in moment generation capacity during a dynamic fatigued condition.

    Science.gov (United States)

    Rao, Guillaume; Berton, Eric; Amarantini, David; Vigouroux, Laurent; Buchanan, Thomas S

    2010-07-01

    Although it is well known that fatigue can greatly reduce muscle forces, it is not generally included in biomechanical models. The aim of the present study was to develop an electromyographic-driven (EMG-driven) biomechanical model to estimate the contributions of flexor and extensor muscle groups to the net joint moment during a nonisokinetic functional movement (squat exercise) performed in nonfatigued and in fatigued conditions. A methodology that aims at balancing the decreased muscle moment production capacity following fatigue was developed. During an isometric fatigue session, a linear regression was created linking the decrease in force production capacity of the muscle (normalized force/EMG ratio) to the EMG mean frequency. Using the decrease in mean frequency estimated through wavelet transforms between dynamic squats performed before and after the fatigue session as input to the previous linear regression, a coefficient accounting for the presence of fatigue in the quadriceps group was computed. This coefficient was used to constrain the moment production capacity of the fatigued muscle group within an EMG-driven optimization model dedicated to estimate the contributions of the knee flexor and extensor muscle groups to the net joint moment. During squats, our results showed significant increases in the EMG amplitudes with fatigue (+23.27% in average) while the outputs of the EMG-driven model were similar. The modifications of the EMG amplitudes following fatigue were successfully taken into account while estimating the contributions of the flexor and extensor muscle groups to the net joint moment. These results demonstrated that the new procedure was able to estimate the decrease in moment production capacity of the fatigued muscle group.

  13. The effectiveness of FES-evoked EMG potentials to assess muscle force and fatigue in individuals with spinal cord injury.

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Estigoni, Eduardo H; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M

    2014-07-14

    The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population.

  14. Changes in surface electromyography signals and kinetics associated with progression of fatigue at two speeds during wheelchair propulsion.

    Science.gov (United States)

    Qi, Liping; Wakeling, James; Grange, Simon; Ferguson-Pell, Martin

    2012-01-01

    The purpose of this study was to determine whether muscle balance is influenced by fatigue in a recordable way, toward creating novel defensive activity strategies for manual wheelchair users (MWUs). Wheelchair propulsion to a point of mild fatigue, level 15 on the Rating of Perceived Exertion scale, was investigated at two different speeds. Surface electromyographic (EMG) activity of 7 muscles was recorded on 14 nondisabled participants. Kinetic variables were measured using a SmartWheel. No significant effect was found of percentage endurance time on kinetic variables for the two propulsion speeds. Fatigue-related changes in the EMG spectra were identified as an increase of EMG intensity and a decrease of mean power frequency as a function of percent endurance time for the tested muscles under both fast and slow speed conditions. The greater increases in activity for propulsive muscles compared with recovery muscles during fast speed wheelchair propulsion indicated muscle imbalance associated with fatiguing wheelchair propulsion. This study shows how kinetic and EMG information might be used as feedback to MWUs to ensure that they conduct activity in ways that do not precipitate injury.

  15. EOG-sEMG Human Interface for Communication.

    Science.gov (United States)

    Tamura, Hiroki; Yan, Mingmin; Sakurai, Keiko; Tanno, Koichi

    2016-01-01

    The aim of this study is to present electrooculogram (EOG) and surface electromyogram (sEMG) signals that can be used as a human-computer interface. Establishing an efficient alternative channel for communication without overt speech and hand movements is important for increasing the quality of life for patients suffering from amyotrophic lateral sclerosis, muscular dystrophy, or other illnesses. In this paper, we propose an EOG-sEMG human-computer interface system for communication using both cross-channels and parallel lines channels on the face with the same electrodes. This system could record EOG and sEMG signals as "dual-modality" for pattern recognition simultaneously. Although as much as 4 patterns could be recognized, dealing with the state of the patients, we only choose two classes (left and right motion) of EOG and two classes (left blink and right blink) of sEMG which are easily to be realized for simulation and monitoring task. From the simulation results, our system achieved four-pattern classification with an accuracy of 95.1%.

  16. Differential control of abdominal muscles during multi-directional support-surface translations in man.

    Science.gov (United States)

    Carpenter, Mark G; Tokuno, Craig D; Thorstensson, Alf; Cresswell, Andrew G

    2008-07-01

    The current study aimed to understand how deep and superficial abdominal muscles are coordinated with respect to activation onset times and amplitudes in response to unpredictable support-surface translations delivered in multiple directions. Electromyographic (EMG) data were recorded intra-muscularly using fine-wire electrodes inserted into the right rectus abdominis (RA), obliquus externus (OE), obliquus internus (OI) and transversus abdominis (TrA) muscles. Twelve young healthy male subjects were instructed to maintain their standing balance during 40 support surface translations (peak acceleration 1.3 m s(-2); total displacement 0.6 m) that were counter-balanced between four different directions (forward, backward, leftward, rightward). Differences between abdominal muscles in EMG onset times were found for specific translation directions. The more superficial RA (backward translations) and OE (forward and leftward translations) muscles had significantly earlier EMG onsets compared to TrA. EMG onset latencies were dependent on translation direction in RA, OE and OI, but independent of direction in TrA. EMG amplitudes in RA and OE were dependent on translation direction within the first 100 ms of activity, whereas responses from the two deeper muscles (TrA and OI) were independent of translation direction during this interval. The current results provide new insights into how abdominal muscles contribute to postural reactions during human stance. Response patterns of deep and superficial abdominal muscles during support surface translations are unlike those previously described during upper-body perturbations or voluntary arm movements, indicating that the neural mechanisms controlling individual abdominal muscles are task-specific to different postural demands.

  17. Experimentally induced stress validated by EMG activity.

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    Rosan Luijcks

    Full Text Available Experience of stress may lead to increased electromyography (EMG activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.

  18. Predicting Blood Lactate Concentration and Oxygen Uptake from sEMG Data during Fatiguing Cycling Exercise

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    Petras Ražanskas

    2015-08-01

    Full Text Available This article presents a study of the relationship between electromyographic (EMG signals from vastus lateralis, rectus femoris, biceps femoris and semitendinosus muscles, collected during fatiguing cycling exercises, and other physiological measurements, such as blood lactate concentration and oxygen consumption. In contrast to the usual practice of picking one particular characteristic of the signal, e.g., the median or mean frequency, multiple variables were used to obtain a thorough characterization of EMG signals in the spectral domain. Based on these variables, linear and non-linear (random forest models were built to predict blood lactate concentration and oxygen consumption. The results showed that mean and median frequencies are sub-optimal choices for predicting these physiological quantities in dynamic exercises, as they did not exhibit significant changes over the course of our protocol and only weakly correlated with blood lactate concentration or oxygen uptake. Instead, the root mean square of the original signal and backward difference, as well as parameters describing the tails of the EMG power distribution were the most important variables for these models. Coefficients of determination ranging from R2 = 0:77 to R2 = 0:98 (for blood lactate and from R2 = 0:81 to R2 = 0:97 (for oxygen uptake were obtained when using random forest regressors.

  19. Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

    Science.gov (United States)

    Simsek, Deniz

    2017-12-01

    The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at pmuscle fatigue (pEMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Predicting Blood Lactate Concentration and Oxygen Uptake from sEMG Data during Fatiguing Cycling Exercise.

    Science.gov (United States)

    Ražanskas, Petras; Verikas, Antanas; Olsson, Charlotte; Viberg, Per-Arne

    2015-08-19

    This article presents a study of the relationship between electromyographic (EMG) signals from vastus lateralis, rectus femoris, biceps femoris and semitendinosus muscles, collected during fatiguing cycling exercises, and other physiological measurements, such as blood lactate concentration and oxygen consumption. In contrast to the usual practice of picking one particular characteristic of the signal, e.g., the median or mean frequency, multiple variables were used to obtain a thorough characterization of EMG signals in the spectral domain. Based on these variables, linear and non-linear (random forest) models were built to predict blood lactate concentration and oxygen consumption. The results showed that mean and median frequencies are sub-optimal choices for predicting these physiological quantities in dynamic exercises, as they did not exhibit significant changes over the course of our protocol and only weakly correlated with blood lactate concentration or oxygen uptake. Instead, the root mean square of the original signal and backward difference, as well as parameters describing the tails of the EMG power distribution were the most important variables for these models. Coefficients of determination ranging from R(2) = 0:77 to R(2) = 0:98 (for blood lactate) and from R(2) = 0:81 to R(2) = 0:97 (for oxygen uptake) were obtained when using random forest regressors.

  1. Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

    Science.gov (United States)

    Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

    2013-01-01

    Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

  2. Upper-Limb Recovery After Stroke: A Randomized Controlled Trial Comparing EMG-Triggered, Cyclic, and Sensory Electrical Stimulation.

    Science.gov (United States)

    Wilson, Richard D; Page, Stephen J; Delahanty, Michael; Knutson, Jayme S; Gunzler, Douglas D; Sheffler, Lynne R; Chae, John

    2016-11-01

    This study compared the effect of cyclic neuromuscular electrical stimulation (NMES), electromyographically (EMG)-triggered NMES, and sensory stimulation on motor impairment and activity limitations in patients with upper-limb hemiplegia. This was a multicenter, single-blind, multiarm parallel-group study of nonhospitalized hemiplegic stroke survivors within 6 months of stroke. A total of 122 individuals were randomized to receive either cyclic NMES, EMG-triggered NMES, or sensory stimulation twice every weekday in 40-minute sessions, over an 8 week-period. Patients were followed for 6 months after treatment concluded. There were significant increases in the Fugl-Meyer Assessment [F(1, 111) = 92.6, P stimulation therapy applied within 6 months of stroke. Improvements were likely a result of spontaneous recovery. There was no difference based on the type of electrical stimulation that was administered. © The Author(s) 2016.

  3. A neuromusculoskeletal model of the human lower limb: towards EMG-driven actuation of multiple joints in powered orthoses.

    Science.gov (United States)

    Sartori, Massimo; Reggiani, Monica; Lloyd, David G; Pagello, Enrico

    2011-01-01

    This paper presents a novel neuromusculoskeletal (NMS) model of the human lower limb that uses the electromyo-graphic (EMG) signals from 16 muscles to estimate forces generated by 34 musculotendon actuators and the resulting joint moments at the hip, knee and ankle joints during varied contractile conditions. Our proposed methodology allows overcoming limitations on force computation shown by currently available NMS models, which constrain the operation of muscles to satisfy joint moments about one single degree of freedom (DOF) only (i.e. knee flexion-extension). The design of advanced human machine interfaces can benefit from the application of our proposed multi-DOF NMS model. The better estimates of the human internal state it provides with respect to single-DOF NMS models, will allow designing more intuitive human-machine interfaces for the simultaneous EMG-driven actuation of multiple joints in lower limb powered orthoses. © 2011 IEEE

  4. Analysis of kinematic, kinetic and electromyographic patterns during root canal preparation with rotary and manual instruments

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    Braulio Pasternak-Júnior

    2012-02-01

    Full Text Available OBJECTIVE: This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG. MATERIAL AND METHODS: The operators prepared one canal with RaCe rotary instruments and another with Flexo-files. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radialis, extensor carpi radialis, brachioradialis, biceps brachii, triceps brachii, middle deltoid, and upper trapezius were recorded. The joint torques of the shoulder, elbow and wrist were calculated using inverse dynamics. In the kinematic analysis, angular movements of the wrist and elbow were classified as low risk factors for work-related musculoskeletal disorders. With respect to the shoulder, the classification was medium-risk. RESULTS: There was no significant difference revealed by the kinetic reports. The EMG results showed that for the middle deltoid and upper trapezius the rotary instrumentation elicited higher values. The flexor carpi radialis and extensor carpi radialis, as well as the brachioradialis showed a higher value with the manual method. CONCLUSION: The muscular recruitment for accomplishment of articular movements for root canal preparation with either the rotary or manual techniques is distinct. Nevertheless, the rotary instrument presented less difficulty in the generation of the joint torque in each articulation, thus, presenting a greater uniformity of joint torques.

  5. Kinematic and Electromyographic Activity Changes during Back Squat with Submaximal and Maximal Loading

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    Hasan U. Yavuz

    2017-01-01

    Full Text Available The aim of this study was to investigate the possible kinematic and muscular activity changes with maximal loading during squat maneuver. Fourteen healthy male individuals, who were experienced at performing squats, participated in this study. Each subject performed squats with 80%, 90%, and 100% of the previously established 1 repetition maximum (1RM. Electromyographic (EMG activities were measured for the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, and erector spinae by using an 8-channel dual-mode portable EMG and physiological signal data acquisition system (Myomonitor IV, Delsys Inc., Boston, MA, USA. Kinematical data were analyzed by using saSuite 2D kinematical analysis program. Data were analyzed with repeated measures analysis of variance (p<0.05. Overall muscle activities increased with increasing loads, but significant increases were seen only for vastus medialis and gluteus maximus during 90% and 100% of 1RM compared to 80% while there was no significant difference between 90% and 100% for any muscle. The movement pattern in the hip joint changed with an increase in forward lean during maximal loading. Results may suggest that maximal loading during squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk.

  6. Neuromuscular demand in a soccer match assessed by a continuous electromyographic recording.

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    Montini, Marco; Felici, Francesco; Nicolò, Andrea; Sacchetti, Massimo; Bazzucchi, Ilenia

    2017-04-01

    The bulk of research investigating soccer player's performance has been concentrated on the metabolic demand, while only few studies focused on the neuromuscular activation. The present study aimed at investigating the activation profile of the leg muscles throughout a 90- minute soccer match. Fifteen football players (18.3±0.7 years) performed: 1) an isometric maximal voluntary contraction (MVC) before the game [MVCpre]; 2) a 90-minute soccer match (composed of two 45-minute periods separated by a 15-minute rest); 3) a second MVC after the match [MVCpost]. Electromyographic (EMG) activity of the Vastus Lateralis (VL) muscle of the dominant leg was recorded during the match. The root mean square (RMS) of the EMG signals was normalized for the maximal RMS obtained during the MVCpre (100%RMSmax) and six intensity classes were created in order to represent the %RMS distribution during the match (1st: 0-20%RMSmax; 2nd: 20-40%RMSmax; 3rd: 40-60%RMSmax; 4th: 60-80%RMSmax; 5th: 80-100%RMSmax; 6th: 100-120%RMSmax). After the 90-minute soccer match, knee extensor MVC failed to show any statistical difference from pre-game values (-4.2%; P>0.05) whilst the neuromuscular activation demonstrated a significant reduction (-26.3%, Psoccer match. Integrating this approach with more traditional ones may help further our understanding of the physiological demand of competitive soccer.

  7. Estimating mood variation from MPF of EMG during walking.

    Science.gov (United States)

    Kinase, Yuta; Venture, Gentiane

    2013-01-01

    The information on the mood included in behavior is classified into nonverbal information, and is included in behavior without necessarily being based on the intention of an agent. Consequently, it is considered that we can estimate the mood from the measurement of the behavior. In this work, we estimate the mood from the surface electromyogram (EMG) information of the muscles of the upper limb during walking. Identification of emotion and mood using EMG information has been done with a variety of methods until now. In addition, it is known that human walking includes information that is specific to the individual and be affected by mood. Therefore, it is thought that the EMG analysis of walking is effective in the identification of human mood. In this work, we made a subject walk in the various mood states and answer psychological tests that measure the mood. We use two types of tasks (music listening and numerical calculation) for evoking different moods. Statistical features of EMG signals are calculated using Fast Fourier Transform (FFT) and Principal Component Analysis (PCA). These statistical features are related with psychological test scores, using regression analysis. In this paper, we have shown the statistical significance of the linear model to predict the variation of mood based on the information on the variation in MPF of EMG data of the muscles of the upper limb during walking with different moods. This shows the validity of such a mapping. However, since the interpretability of the model is still low, it cannot be said that the model is able to accurately represent the mood variation. Creating a model with high accuracy is a key issue in the future.

  8. Treatment for TMD with occlusal splint and electromyographic control: application of the FARC protocol in a Brazilian population.

    Science.gov (United States)

    Vieira e Silva, Carolina A; da Silva, Marco Antônio M Rodrigues; Melchior, Melissa de Oliveira; de Felício, Cláudia Maria; Sforza, Chiarella; Tartaglia, Gianluca M

    2012-07-01

    The purpose of this study was to apply Functional Anatomy Research Center (FARC) Protocol of TMD treatment, which includes the use of a specific type of mandibular occlusal splint, adjusted based on the electromyographic index, in a group of 15 patients with disc displacement, classified according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and then analyzing the results compared with the control group. The clinical evaluations were completed both before and after the treatment. Electromyographic (EMG) data was collected and recorded on the day the splint was inserted (visit 1), after one week (visit 2) and after five weeks of treatment (visit 3). The control group consisted of 15 asymptomatic subjects, according to the same diagnostic criteria (RDC/TMD), who were submitted to the same evaluations with the same interval periods as the treatment group. Immediately after splint adjustment, masseter muscle symmetry and total muscular activity were significantly different with than without the splint (p < 0.05), showing an increased neuromuscular coordination. After treatment, significant variations (p < .05) were found in mouth opening and in pain remission. There were no significant differences among the three sessions, either with or without the splint. There were significant differences between the TMD and control groups for all analyzed indices of muscular symmetry, activity and torque, with the exception of total muscular activity. The use of the splint promoted balance of the EMG activities during its use, relieving symptoms. EMG parameters identified neuromuscular imbalance, and allowed an objective analysis of different phases of TMD treatment, differentiating individuals with TMD from the asymptomatic subjects.

  9. Biofeedback and the electromyographic activity of pelvic floor muscles in pregnant women Biofeedback na atividade eletromiográfica dos músculos do assoalho pélvico em gestantes

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    Roberta L. A. Batista

    2011-10-01

    Full Text Available BACKGROUND: Maintaining continence is among the functions of the pelvic floor muscles (PFM and their dysfunction can cause urinary incontinence (UI, which is a common occurrence during pregnancy and the puerperal period. Pelvic floor muscle training (PFMT, therefore, is important during pregnancy, although most women perform the muscle contractions unsatisfactorily. OBJECTIVES: This study is an exploratory analysis of the results of three electromyographic (EMG activity biofeedback sessions in pregnant women. METHODS: The study sample included 19 nulliparous women with low risk pregnancies. The participants performed three sessions of EMG biofeedback consisting of slow and fast contractions. The average value of the normalized amplitudes of surface electromyography was used to evaluate the results. The linear regression model with mixed effects was used for statistical analysis, with the EMG data normalized by maximum voluntary contraction (MVC. RESULTS: A steady increase in EMG amplitude was observed during each contraction and by the end of the biofeedback sessions, although this difference was only significant when comparing the first tonic contraction of each session (p=0.03. CONCLUSIONS: The results indicate that three sessions of training with biofeedback improved PFM EMG activity during the second trimester in women with low-risk pregnancies. The effectiveness of this protocol should be further investigated in randomized controlled trials.CONTEXTUALIZAÇÃO: Dentre as funções dos músculos do assoalho pélvico (MAPs, pode-se citar a manutenção da continência, sendo que sua disfunção pode causar a incontinência urinária (IU, muito frequente no período gestacional e no puerpério. Diante disso, se faz importante o treinamento dos músculos do assoalho pélvico (TMAP durante o período gestacional, entretanto grande parte das mulheres realiza a contração dessa musculatura de maneira insatisfatória. OBJETIVOS: Realizar uma an

  10. Motor imagery modulation of postural sway is accompanied by changes in the EMG-COP association.

    Science.gov (United States)

    Lemos, Thiago; Rodrigues, Erika C; Vargas, Claudia D

    2014-08-08

    Motor imagery (MI) performed in an upright stance promotes increases in postural sway without changes in usual amplitude measures of calf muscle EMG. However, postural muscle activity can also be determined from the temporal association between EMG and center of pressure (COP) displacements. In this study we investigated whether the MI modulation of postural sway is accompanied by changes in EMG-COP association. Surface EMG from the lateral gastrocnemius (LG) muscle and COP coordinates were collected from 12 subjects while they imagined themselves performing a rising on tiptoes movement via kinesthetic or visual imagery. As a control condition subjects were requested to imagine singing a song. The standard deviation of the forward-backward COP sway and the coefficient of variation of the EMG were calculated and compared across tasks. The degree of association between COP sways and LG activity was evaluated through a cross-correlation function. Kinesthetic imagery promoted a larger COP displacement than both visual and control imagery (pCOP association during kinesthetic imagery compared to control imagery (p=0.02), whereas the EMG-COP association in visual imagery was not different from that observed during kinesthetic or control imagery (p>0.19). In conclusion, kinesthetic imagery resulted in a higher EMG-COP temporal association. Subliminal fringe mechanisms may account for the imagery effects on muscle activity and postural sway during upright stance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Femoral anteversion influences vastus medialis and gluteus medius EMG amplitude: composite hip abductor EMG amplitude ratios during isometric combined hip abduction-external rotation.

    Science.gov (United States)

    Nyland, J; Kuzemchek, S; Parks, M; Caborn, D N M

    2004-04-01

    This prospective study evaluated differences in vastus medialis (VM) and gluteus medius (GM) EMG amplitude:composite hip abductor (gluteus maximus, gluteus medius, tensor fascia lata) EMG amplitude ratios among subjects with low or high relative femoral anteversion. Data were collected during the performance of a non-weight bearing, non-sagittal plane maximal volitional effort isometric combined hip abduction-external rotation maneuver. Eighteen nonimpaired athletically active females participated in this surface EMG study. Medial hip rotation (relative femoral anteversion estimate) was measured with a handheld goniometer. Subjects were grouped by medial hip rotation displacement (group 1 42 degrees =52.7+/-7 degrees ) for statistical analysis (Mann Whitney U-tests, p < 0.05). Group 2 had decreased VM (42+/-23% vs. 69+/-30%, U=19, p=0.034) and GM (62+/-25% vs. 96+/-39%, U=19, p=0.034) normalized mean peak EMG amplitude:composite mean peak hip abductor EMG amplitude ratios compared to group 1. Decreased normalized VM (-27%) and GM (-34%) EMG amplitudes among subjects with increased relative femoral anteversion suggest reduced dynamic frontal and transverse plane femoral control from these muscles, possibly contributing to the increased incidence of non-contact knee injury observed among athletic females.

  12. What do facial expressions of emotion express in young children? The relationship between facial display and EMG measures

    Directory of Open Access Journals (Sweden)

    Michela Balconi

    2014-04-01

    Full Text Available The present paper explored the relationship between emotional facial response and electromyographic modulation in children when they observe facial expression of emotions. Facial responsiveness (evaluated by arousal and valence ratings and psychophysiological correlates (facial electromyography, EMG were analyzed when children looked at six facial expressions of emotions (happiness, anger, fear, sadness, surprise and disgust. About EMG measure, corrugator and zygomatic muscle activity was monitored in response to different emotional types. ANOVAs showed differences for both EMG and facial response across the subjects, as a function of different emotions. Specifically, some emotions were well expressed by all the subjects (such as happiness, anger and fear in terms of high arousal, whereas some others were less level arousal (such as sadness. Zygomatic activity was increased mainly for happiness, from one hand, corrugator activity was increased mainly for anger, fear and surprise, from the other hand. More generally, EMG and facial behavior were highly correlated each other, showing a “mirror” effect with respect of the observed faces.

  13. A hybrid brain-machine interface based on EEG and EMG activity for the motor rehabilitation of stroke patients.

    Science.gov (United States)

    Sarasola-Sanz, Andrea; Irastorza-Landa, Nerea; Lopez-Larraz, Eduardo; Bibian, Carlos; Helmhold, Florian; Broetz, Doris; Birbaumer, Niels; Ramos-Murguialday, Ander

    2017-07-01

    Including supplementary information from the brain or other body parts in the control of brain-machine interfaces (BMIs) has been recently proposed and investigated. Such enriched interfaces are referred to as hybrid BMIs (hBMIs) and have been proven to be more robust and accurate than regular BMIs for assistive and rehabilitative applications. Electromyographic (EMG) activity is one of the most widely utilized biosignals in hBMIs, as it provides a quite direct measurement of the motion intention of the user. Whereas most of the existing non-invasive EEG-EMG-hBMIs have only been subjected to offline testings or are limited to one degree of freedom (DoF), we present an EEG-EMG-hBMI that allows the simultaneous control of 7-DoFs of the upper limb with a robotic exoskeleton. Moreover, it establishes a biologically-inspired hierarchical control flow, requiring the active participation of central and peripheral structures of the nervous system. Contingent visual and proprioceptive feedback about the user's EEG and EMG activity is provided in the form of velocity modulation during functional task training. We believe that training with this closed-loop system may facilitate functional neuroplastic processes and eventually elicit a joint brain and muscle motor rehabilitation. Its usability is validated during a real-time operation session in a healthy participant and a chronic stroke patient, showing encouraging results for its application to a clinical rehabilitation scenario.

  14. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    Science.gov (United States)

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-01-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  15. Electromyographic fatigue in neck/shoulder muscles and endurance in women with repetitive work.

    Science.gov (United States)

    Hansson, G A; Strömberg, U; Larsson, B; Ohlsson, K; Balogh, I; Moritz, U

    1992-11-01

    EMG was recorded with surface electrodes from the trapezius and deltoid muscles during a static endurance test at approximately 20% of maximal voluntary contraction. Objective parameters for localized muscular fatigue were derived from the time course of the root mean square (RMS) and mean power frequency (MPF) of the EMG recordings. Isotonic regression is introduced as a tool for assessment of such parameters. The most pronounced sign of fatigue for trapezius was an increase in the RMS values, while for deltoid it was a decrease in the MPF values. This could be explained by the different functions of the two muscles. The endurance time for a group of 11 women in industrial work with repetitive short-cycled work tasks who were diagnosed with neck/shoulder disorders (tension neck) was significantly shorter (p less than 0.05) than for a group with the same work, but without neck/shoulder disorders (n = 11), and shorter than for a control group (n = 11). Regarding the EMG fatigue measures, there were no significant differences between the three groups. We did not find any relationships between endurance time and the EMG parameters. The results indicate that neck/shoulder disorders were not associated with divergent mechanisms for developing fatigue in the muscles, as recorded with surface EMG.

  16. Effect of L-Glutamine Supplementation on Electromyographic Activity of the Quadriceps Muscle Injured By Eccentric Exercise

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    Farhad Rahmani Nia

    2013-06-01

    Full Text Available   Objective(s: The purpose of the present study was to examine the effects of L-glutamine on electromyographic (EMG activity of the quadriceps muscle injured by eccentric exercise (EE.   Materials and Methods: Seventeen healthy men (age: 22.35±2.27 yr; body mass: 69.91±9.78 kg; height: 177.08±4.32 cm were randomly and double-blind study with subjects assigned to either an L-glutamine supplementation (n=9 or placebo (n=8 group. The subjects in two groups were asked to take three times during a week for 4 weeks. Each subject was screened for dietary habits before inclusion into the study. Participants performed 6 set to exhaustion eccentric leg extensions at 75% of 1RM and rest intervals were 3 min among sets. Pain Assessment Scale (PAS, EMG activity and range of motion (ROM measurements were taken before exercise protocol and 24 and 48 hr afterwards. Results: There was no statistically significant difference between groups in perceived muscle soreness (SOR, ROM and EMG activity (P < 0.05. Conclusion: The results indicate that L-glutamine supplementation has no significant effect on muscle injury markers in between groups, although glutamine supplementation attenuated delayed onset muscle soreness (DOMS effects in sup group.

  17. Comparison of Electromyographic Activity of the Superior and Inferior Portions of the Gluteus Maximus Muscle During Common Therapeutic Exercises.

    Science.gov (United States)

    Selkowitz, David M; Beneck, George J; Powers, Christopher M

    2016-09-01

    Study Design Controlled laboratory study, repeated-measures design. Background Previous studies have reported that the superior and inferior portions of the gluteus maximus have different functional roles. Knowledge of how the different portions of the gluteus maximus are activated during therapeutic exercise may lead to more specific exercise prescription. Objective To compare muscle activation of the superior and inferior portions of the gluteus maximus during commonly used therapeutic exercises. Methods Twenty healthy persons participated. Electromyographic (EMG) signals were obtained from the superior and inferior portions of the gluteus maximus using fine-wire electrodes. Normalized EMG signal amplitudes were compared between the superior and inferior gluteus maximus across 11 exercises using a 2-way repeated-measures analysis of variance. Results The superior portion of the gluteus maximus had significantly greater relative EMG activity than the inferior portion of the gluteus maximus during exercises that incorporated elements of hip abduction and/or external rotation (5 of 11 exercises evaluated). There was no significant difference in activation between the superior and inferior portions of the gluteus maximus during the remaining 6 exercises. Conclusion The results of the present study demonstrate preferential activation of the superior portion of the gluteus maximus during exercises that incorporate elements of hip abduction and/or external rotation. In contrast, exercises that primarily involve hip extension target both portions of the gluteus maximus to a similar extent. J Orthop Sports Phys Ther 2016;46(9):794-799. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6493.

  18. Statistically significant contrasts between EMG waveforms revealed using wavelet-based functional ANOVA

    Science.gov (United States)

    McKay, J. Lucas; Welch, Torrence D. J.; Vidakovic, Brani

    2013-01-01

    We developed wavelet-based functional ANOVA (wfANOVA) as a novel approach for comparing neurophysiological signals that are functions of time. Temporal resolution is often sacrificed by analyzing such data in large time bins, increasing statistical power by reducing the number of comparisons. We performed ANOVA in the wavelet domain because differences between curves tend to be represented by a few temporally localized wavelets, which we transformed back to the time domain for visualization. We compared wfANOVA and ANOVA performed in the time domain (tANOVA) on both experimental electromyographic (EMG) signals from responses to perturbation during standing balance across changes in peak perturbation acceleration (3 levels) and velocity (4 levels) and on simulated data with known contrasts. In experimental EMG data, wfANOVA revealed the continuous shape and magnitude of significant differences over time without a priori selection of time bins. However, tANOVA revealed only the largest differences at discontinuous time points, resulting in features with later onsets and shorter durations than those identified using wfANOVA (P < 0.02). Furthermore, wfANOVA required significantly fewer (∼¼×; P < 0.015) significant F tests than tANOVA, resulting in post hoc tests with increased power. In simulated EMG data, wfANOVA identified known contrast curves with a high level of precision (r2 = 0.94 ± 0.08) and performed better than tANOVA across noise levels (P < <0.01). Therefore, wfANOVA may be useful for revealing differences in the shape and magnitude of neurophysiological signals (e.g., EMG, firing rates) across multiple conditions with both high temporal resolution and high statistical power. PMID:23100136

  19. Peak and average rectified EMG measures: which method of data reduction should be used for assessing core training exercises?

    Science.gov (United States)

    Hibbs, A E; Thompson, K G; French, D N; Hodgson, D; Spears, I R

    2011-02-01

    Core strengthening and stability exercises are fundamental for any conditioning training program. Although surface electromyography (sEMG) is used to quantify muscle activity there is a lack of research using this method to investigate the core musculature and core stability. Two types of data reduction are commonly used for sEMG; peak and average rectified EMG methods. Peak EMG has been infrequently reported in the literature with regard to the assessment of core training while even fewer studies have incorporated average rectified EMG data (ARV). The aim of the study was to establish the repeatability of peak and average rectified EMG data during core training exercises and their interrelationship. Ten male highly trained athletes (inter-subject repeatability group; age, 18 ± 1.2 years; height, 176.5 ± 3.2 cm; body mass, 71 ± 4.5 kg) and one female highly trained athlete (intra-subject repeatability group; age; 27 years old; height; 180 cm; weight; 53 kg) performed five maximal voluntary isometric contractions (MVIC) and five core exercises, chosen to represent a range of movement and muscle recruitment patterns. Peak EMG and ARV EMG were calculated for eight core muscles (rectus abdominis, RA; external oblique, EO; internal oblique, IO; multifidis, MF; latissimus dorsi, LD; longissimus, LG; gluteus maximus, GM; rectus femoris, RF) using sEMG. Average coefficient of variation (CV%) for peak EMG across all the exercises and muscles was 45%. This is in comparison to 35% for the ARV method, which was found to be a significant difference (Pexercise. Analysis of the inter-subject and intra-subject CV% values suggest that these exercises and muscles are sufficiently repeatable using sEMG. Five muscles were highly correlated (R>0.70; RA, EO, MF, GM, LG) between peak and ARV EMG suggesting, that for these core muscles, the two methods provide a similar evaluation of muscle activity. However, for other muscles (IO, RF, LD) the relationship was found to range from poor

  20. EMG spectral indices and muscle power fatigue during dynamic contractions.

    Science.gov (United States)

    González-Izal, M; Malanda, A; Navarro-Amézqueta, I; Gorostiaga, E M; Mallor, F; Ibañez, J; Izquierdo, M

    2010-04-01

    The purpose of this study was to examine acute exercise-induced changes on muscle power output and surface electromyography (sEMG) parameters (amplitude and spectral indices of muscle fatigue) during a dynamic fatiguing protocol. Fifteen trained subjects performed five sets consisting of 10 leg presses (10RM), with 2min rest between sets. Surface electromyography was recorded from vastus medialis (VM) and lateralis (VL) and biceps femoris (BF) muscles. A number of EMG-based parameters were compared for estimation accuracy and sensitivity to detect peripheral muscle fatigue. These were: Mean Average Voltage, median spectral frequency, Dimitrov spectral index of muscle fatigue (FI(nsm5)), as well as other parameters obtained from a time-frequency analysis (Choi-Williams distributions) such as mean and variance of the instantaneous frequency and frequency variance. The log FI(nsm5) as a single parameter predictor accounted for 37% of the performance variance of changes in muscle power and the log FI(nsm5) and MFM as a two factor combination predictor accounted for 44%. Peripheral impairments assessed by sEMG spectral index FI(nsm5) may be a relevant factor involved in the loss of power output after dynamic high-loading fatiguing task. 2009 Elsevier Ltd. All rights reserved.

  1. Electromyographic activity of preterm newborns in the kangaroo position: a cohort study

    OpenAIRE

    Miranda, Rafael Moura; Cabral Filho, José Eulálio; Diniz, Kaísa Trovão; Souza Lima, Geisy Maria; Vasconcelos, Danilo de Almeida

    2014-01-01

    Objective To compare the electromyographic activity of preterm newborns placed in the kangaroo position with the activity of newborns not placed in this position. Design A cohort study. Setting A Kangaroo Unit sector and a Nursery sector in a secondary and tertiary care at a mother-child hospital in Recife, Brazil. Participants Preterm infants of gestational age 27–34 weeks (n=38) and term infants (n=39). Primary and secondary outcome measures Surface electromyography was used to investigate ...

  2. Seizure detection algorithms based on EMG signals

    DEFF Research Database (Denmark)

    Conradsen, Isa

    Background: the currently used non-invasive seizure detection methods are not reliable. Muscle fibers are directly connected to the nerves, whereby electric signals are generated during activity. Therefore, an alarm system on electromyography (EMG) signals is a theoretical possibility. Objective......: to show whether medical signal processing of EMG data is feasible for detection of epileptic seizures. Methods: EMG signals during generalised seizures were recorded from 3 patients (with 20 seizures in total). Two possible medical signal processing algorithms were tested. The first algorithm was based...... the frequency-based algorithm was efficient for detecting the seizures in the third patient. Conclusion: Our results suggest that EMG signals could be used to develop an automatic seizuredetection system. However, different patients might require different types of algorithms /approaches....

  3. Effect of concrete block weight and wall height on electromyographic activity and heart rate of masons.

    Science.gov (United States)

    Anton, D; Rosecrance, J C; Gerr, F; Merlino, L A; Cook, T M

    2005-08-15

    Work-related musculoskeletal disorders (MSDs) are common among construction workers, such as masons. Few interventions are available to reduce masons' exposure to heavy lifting, a risk factor for MSDs. The purpose of this study was to determine whether one such intervention, the use of light-weight concrete blocks (LWBs), reduces physiological loads compared to standard-weight blocks (SWBs). Using a repeated measures design, 21 masons each constructed two 32-block walls, seven courses (rows) high, entirely of either SWBs or LWBs. Surface electromyography (EMG), from arm and back muscles, and heart rate was sampled. For certain muscles, EMG amplitudes were slightly lower when masons were laying LWBs compared to SWBs. Upper back and forearm extensor EMG amplitudes were greater for the higher wall courses for both block weights. There were no significant differences in heart rate between the two blocks. Interventions that address block weight and course height may be effective for masons.

  4. Embodiment and the origin of interval timing: kinematic and electromyographic data.

    Science.gov (United States)

    Addyman, Caspar; Rocha, Sinead; Fautrelle, Lilian; French, Robert M; Thomas, Elizabeth; Mareschal, Denis

    2017-03-01

    Recent evidence suggests that interval timing (the judgment of durations lasting from approximately 500 ms. to a few minutes) is closely coupled to the action control system. We used surface electromyography (EMG) and motion capture technology to explore the emergence of this coupling in 4-, 6-, and 8-month-olds. We engaged infants in an active and socially relevant arm-raising task with seven cycles and response period. In one condition, cycles were slow (every 4 s); in another, they were fast (every 2 s). In the slow condition, we found evidence of time-locked sub-threshold EMG activity even in the absence of any observed overt motor responses at all three ages. This study shows that EMGs can be a more sensitive measure of interval timing in early development than overt behavior.

  5. EMG amplifier with wireless data transmission

    Science.gov (United States)

    Kowalski, Grzegorz; Wildner, Krzysztof

    2017-08-01

    Wireless medical diagnostics is a trend in modern technology used in medicine. This paper presents a concept of realization, architecture of hardware and software implementation of an elecromyography signal (EMG) amplifier with wireless data transmission. This amplifier consists of three components: analogue processing of bioelectric signal module, micro-controller circuit and an application enabling data acquisition via a personal computer. The analogue bioelectric signal processing circuit receives electromyography signals from the skin surface, followed by initial analogue processing and preparation of the signals for further digital processing. The second module is a micro-controller circuit designed to wirelessly transmit the electromyography signals from the analogue signal converter to a personal computer. Its purpose is to eliminate the need for wired connections between the patient and the data logging device. The third block is a computer application designed to display the transmitted electromyography signals, as well as data capture and analysis. Its purpose is to provide a graphical representation of the collected data. The entire device has been thoroughly tested to ensure proper functioning. In use, the device displayed the captured electromyography signal from the arm of the patient. Amplitude- frequency characteristics were set in order to investigate the bandwidth and the overall gain of the device.

  6. FEATURE EXTRACTION FOR EMG BASED PROSTHESES CONTROL

    Directory of Open Access Journals (Sweden)

    R. Aishwarya

    2013-01-01

    Full Text Available The control of prosthetic limb would be more effective if it is based on Surface Electromyogram (SEMG signals from remnant muscles. The analysis of SEMG signals depend on a number of factors, such as amplitude as well as time- and frequency-domain properties. Time series analysis using Auto Regressive (AR model and Mean frequency which is tolerant to white Gaussian noise are used as feature extraction techniques. EMG Histogram is used as another feature vector that was seen to give more distinct classification. The work was done with SEMG dataset obtained from the NINAPRO DATABASE, a resource for bio robotics community. Eight classes of hand movements hand open, hand close, Wrist extension, Wrist flexion, Pointing index, Ulnar deviation, Thumbs up, Thumb opposite to little finger are taken into consideration and feature vectors are extracted. The feature vectors can be given to an artificial neural network for further classification in controlling the prosthetic arm which is not dealt in this paper.

  7. An Electromyograph Comparison of an Isokenetic Bench Press at Three Speeds.

    Science.gov (United States)

    Ridgeway, M.; And Others

    The muscle action potentials (MAP) of the anterior deltoid, pectoralis major, biceps brachii, and the triceps muscle were studied by quantitative electromyography (emg) during a bench press exercise at three controlled speeds. Bipolar surface electrodes with standard placement were employed throughout the study. Eleven volunteer college women…

  8. Time and frequency domain analysis of surface myoelectric signals during electrically-elicited cramps.

    Science.gov (United States)

    Minetto, M A; Botter, A; De Grandis, D; Merletti, R

    2009-02-01

    To examine if different frequencies of electrical stimulation trigger different sized cramps in the abductor hallucis muscle and to analyze their surface electromyographic (EMG) behaviour in both time and frequency domains. Fifteen subjects were studied. Stimulation trains of 150 pulses were applied to the muscle motor point. Frequency was increased (starting from 4pps with 2-pps steps) until a cramp developed. Current intensity was 30% higher than that eliciting maximal M-waves. After the first cramp ("threshold cramp"), a 30-minute rest was provided before a second cramp ("above-threshold cramp") was elicited with a frequency increased by 50% with respect to that eliciting the first cramp. We found greater EMG amplitude and a compression of the power spectrum for above-threshold cramps with respect to threshold cramps. M-wave changes (ranging between small decreases of M-wave amplitude to complete M-wave disappearance) occurred and progressively increased throughout stimulation trains. Significant positive correlations were found between estimates of EMG amplitude during cramps and estimated reductions of M-wave amplitude. Varying frequencies of electrical stimulation triggered different sized cramps. Moreover, decreases in M-wave amplitude were observed during both threshold and above-threshold stimulations. The choice of the stimulation frequency has relevance for optimizing electrical stimulation protocols for the study of muscle cramps in both healthy and pathological subjects.

  9. Association between changes in electromyographic signal amplitude and abdominal muscle thickness in individuals with and without lumbopelvic pain.

    Science.gov (United States)

    Whittaker, Jackie L; McLean, Linda; Hodder, Joanne; Warner, Martin B; Stokes, Maria J

    2013-01-01

    Validation study. To investigate the association between changes in electromyographic (EMG) signal amplitude and sonographic measures of muscle thickness of 4 abdominal muscles, during 2 clinical tests, in adults with and without lumbopelvic pain. There is a trend in rehabilitation to use ultrasound imaging (USI) to determine the extent of abdominal muscle contraction. However, the literature investigating the relationship between abdominal muscle thickness change and level of activation is inconclusive and has not included clinically relevant tasks. Simultaneous recording from fine-wire EMG and USI was performed for 4 abdominal muscles, in 7 adults with lumbopelvic pain (mean ± SD age, 29.7 ± 12.0 years) and 7 adults without lumbopelvic pain (32.0 ± 10.6 years), during an active straight leg raise (ASLR) test and an abdominal drawing-in maneuver (ADIM). Cross-correlation functions and linear regression analyses were used to describe the relationship between the 2 measures. Analyses of variance were used to compare individuals with and without lumbopelvic pain, with an alpha set at .05. Across all muscles, peak cross-correlation values were low (ASLR, r = 0.28 ± 0.09; ADIM, r = 0.35 ± 0.11), and there was large variability in associated time lags (ASLR, τ = 0.69 ± 2.56 seconds; ADIM, τ = 0.53 ± 3.75 seconds). Regression analyses did not detect a systematic pattern of association between EMG signal amplitude and USI measurements, and analyses of variance revealed no differences between cohorts. These results suggest a weak relationship between EMG amplitude and abdominal muscle thickness change measured with USI during the ADIM and ASLR, and raise questions about thickness change derived from USI as a measure of muscular activity for the abdominal musculature.

  10. The Effect of Auricular and Systemic Acupuncture on the Electromyographic Activity of the Trapezius Muscle with Trigger Points—A Pilot Study

    Directory of Open Access Journals (Sweden)

    Patrícia Silva de Camargo

    2018-02-01

    Full Text Available The purpose of this study was to analyze and compare intra and intergroup the immediate effect of the auricular and LR8 systemic acupuncture on the electromyographic activity of the trapezius with the trigger points. This is an experimental clinical trial; 40 people were split in 4 distinct groups (n = 10: GI mustard seed application in the auricular acupoint; GII bilateral needle application in the LR8 acupoint; GIII combination of the techniques; GIV/Control Group mustard seed application in an acupoint not linked to the muscle tension. The EMG was used to assess the muscle contraction for 5 seconds during the resting time and during the isometric contraction time. The EMG signal was first collect without the acupuncture intervention; then both techniques were applied for 5 minutes; and the EMG was collected again right after these applications. The Shapiro-Wilk test was used, the t test was paired with the Wilcoxon test to the intragroup comparison; One-way analysis of variance test for intergroup comparison. There was no statistical difference in the intragroup comparison for the groups. The same happened to the intergroup comparison before and after application. Systemic and auricular acupuncture did not promote immediate changes in the EMG activity of the trapezius muscle in individuals with MTrPs.

  11. EMG feature assessment for myoelectric pattern recognition and channel selection: a study with incomplete spinal cord injury.

    Science.gov (United States)

    Liu, Jie; Li, Xiaoyan; Li, Guanglin; Zhou, Ping

    2014-07-01

    Myoelectric pattern recognition with a large number of electromyogram (EMG) channels provides an approach to assessing motor control information available from the recorded muscles. In order to develop a practical myoelectric control system, a feature dependent channel reduction method was developed in this study to determine a small number of EMG channels for myoelectric pattern recognition analysis. The method selects appropriate raw EMG features for classification of different movements, using the minimum Redundancy Maximum Relevance (mRMR) and the Markov random field (MRF) methods to rank a large number of EMG features, respectively. A k-nearest neighbor (KNN) classifier was used to evaluate the performance of the selected features in terms of classification accuracy. The method was tested using 57 channels' surface EMG signals recorded from forearm and hand muscles of individuals with incomplete spinal cord injury (SCI). Our results demonstrate that appropriate selection of a small number of raw EMG features from different recording channels resulted in similar high classification accuracies as achieved by using all the EMG channels or features. Compared with the conventional sequential forward selection (SFS) method, the feature dependent method does not require repeated classifier implementation. It can effectively reduce redundant information not only cross different channels, but also cross different features in the same channel. Such hybrid feature-channel selection from a large number of EMG recording channels can reduce computational cost for implementation of a myoelectric pattern recognition based control system. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  12. Effect of the kangaroo position on the electromyographic activity of preterm children: a follow-up study.

    Science.gov (United States)

    Diniz, Kaísa Trovão; Cabral-Filho, José Eulálio; Miranda, Rafael Moura; Souza Lima, Geisy Maria; Vasconcelos, Danilo de Almeida

    2013-05-16

    One of the components of the Kangaroo Method (KM) is the adoption of the Kangaroo Position. The skin-to-skin contact and the vertical position the child adopts when in this position may provide sensorial, vestibular and postural stimuli for the newborn. The Kangaroo Position may encourage vestibular stimuli and a flexed posture of the limbs, suggesting the hypothesis that the Kangaroo Position may have an impact on flexor muscle tone. The effect of these stimuli on the motor features of the newborn has not been the subject of much investigation. No study has yet been conducted to determine whether the Kangaroo Position may progressively increase electromyographic activity or whether this increase persists until term-equivalent age. The aim of this study was to evaluate the effect of the Kangaroo Position on the electromyographic activity of preterm children. A follow-up study was carried out between July and November 2011 at the Instituto de Medicina Integral Prof. Fernando Figueira (IMIP), Recife-Brazil, using a sample of 30 preterm children. Surface Eletromyography (SEMG) was used to investigate the muscle activity of biceps brachii. The electromyographic readings were taken immediately before (0 h) and after 24 h, 48 h, 72 h, 96 h of application of the Kangaroo Position as well as at the term equivalent age in each baby. Electromyographic activity was analyzed using the Root Mean Square (RMS) and the mean values of the times were analyzed by way of analysis of variance for repeated measures and the Tukey test. Electromyographic activity of the biceps brachii varied and increased over the whole 96h period (RMS:0 h = 36.5 and 96 h = 52.9) (F(5.174) = 27.56; p Position leads to a growing increase in the electromyographic activity of preterm children's biceps brachii after up to 96 h of stimulation and this response persists until at least the 21st day after this period.

  13. Kettlebell swing targets semitendinosus and supine leg curl targets biceps femoris: an EMG study with rehabilitation implications.

    Science.gov (United States)

    Zebis, Mette Kreutzfeldt; Skotte, Jørgen; Andersen, Christoffer H; Mortensen, Peter; Petersen, Højland H; Viskaer, Tine C; Jensen, Tanja L; Bencke, Jesper; Andersen, Lars L

    2013-12-01

    The medial hamstring muscle has the potential to prevent excessive dynamic valgus and external rotation of the knee joint during sports. Thus, specific training targeting the medial hamstring muscle seems important to avoid knee injuries. The aim was to investigate the medial and lateral hamstring muscle activation balance during 14 selected therapeutic exercises. The study design involved single-occasion repeated measures in a randomised manner. Sixteen female elite handball and soccer players with a mean (SD) age of 23 (3) years and no previous history of knee injury participated in the present study. Electromyographic (EMG) activity of the lateral (biceps femoris - BF) and medial (semitendinosus - ST) hamstring muscle was measured during selected strengthening and balance/coordination exercises, and normalised to EMG during isometric maximal voluntary contraction (MVC). A two-way analysis of variance was performed using the mixed procedure to determine whether differences existed in normalised EMG between exercises and muscles. Kettlebell swing and Romanian deadlift targeted specifically ST over BF (Δ17-22%, p<0.05) at very high levels of normalised EMG (73-115% of MVC). In contrast, the supine leg curl and hip extension specifically targeted the BF over the ST (Δ 20-23%, p<0.05) at very high levels of normalised EMG (75-87% of MVC). Specific therapeutic exercises targeting the hamstrings can be divided into ST dominant or BF dominant hamstring exercises. Due to distinct functions of the medial and lateral hamstring muscles, this is an important knowledge in respect to prophylactic training and physical therapist practice.

  14. External abdominal oblique muscle ultrasonographic thickness changes is not an appropriate surrogate measure of electromyographic activity during isometric trunk contractions.

    Science.gov (United States)

    Rabello, Lucas M; Gagnon, Dany; da Silva, Rubens A; Paquette, Philippe; Larivière, Christian

    2015-01-01

    The function of specific abdominal muscles can be assessed using both electromyography (EMG) and ultrasound imaging (USI) thickness measures. However, the relationship between these two measurements is not conclusive during sitting isometric trunk efforts. This study was conducted to assess the relationship between USI thickness and EMG amplitude measures of the right external oblique (EO) muscle during isometric efforts in the sitting position. Eighteen subjects performed ramp isometric efforts progressing from 0 to 50% of their maximal voluntary contraction (MVC) in three trunk directions on a dynamometer: (1) forward flexion; (2) right lateral flexion; and (3) left axial rotation. USI and surface EMG amplitude measures of the EO muscle were recorded concomitantly and both normalized against rest values and maximal EMG, respectively. EO muscle was significantly more activated (p muscle activity. USI thickness measures should be interpreted with great caution in research and clinical settings.

  15. Experimental muscle pain during a forward lunge--the effects on knee joint dynamics and electromyographic activity

    DEFF Research Database (Denmark)

    Henriksen, Marius; Alkjaer, T; Simonsen, Erik Bruun

    2009-01-01

    OBJECTIVE: The purpose of this study was to investigate whether the knee joint dynamics during a forward lunge could be modulated by experimentally induced vastus medialis pain in healthy subjects. DESIGN: Randomised cross-over study. SETTING: Biomechanical movement laboratory. PARTICIPANTS: 20 h...... of muscle pain and prevention of injuries during activities involving the knee joint.......OBJECTIVE: The purpose of this study was to investigate whether the knee joint dynamics during a forward lunge could be modulated by experimentally induced vastus medialis pain in healthy subjects. DESIGN: Randomised cross-over study. SETTING: Biomechanical movement laboratory. PARTICIPANTS: 20....... Isotonic saline (0.9%) was used as control. MAIN OUTCOME MEASUREMENTS: Three-dimensional movement analyses were performed and inverse dynamics were used to calculate joint kinematics and kinetics for ankle, knee and hip joints. Electromyographic (EMG) signals of the hamstrings and quadriceps muscles were...

  16. Utility of electromyographic fatigue threshold during treadmill running.

    Science.gov (United States)

    Crozara, Luciano F; Castro, Alex; De Almeida Neto, Antonio F; Laroche, Dain P; Cardozo, Adalgiso C; Gonçalves, Mauro

    2015-12-01

    We investigated 2 different methods for determining muscle fatigue threshold by electromyography (EMG). Thirteen subjects completed an incremental treadmill running protocol for EMG fatigue threshold (EMGFT ) determination based on the critical power concept (EMGFT 1) and the breakpoint in the linear relationship between EMG amplitude and exercise intensity (EMGFT 2). Then, both the EMGFT 1 and EMGFT 2 were tested in a continuous treadmill running protocol. EMG was recorded from the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and lateral gastrocnemius (LG) muscles. For BF, EMGFT 2 was higher than EMGFT 1, and EMGFT 1 for BF was lower than EMGFT 1 for LG. EMG of RF was higher at EMGFT 2 than at EMGFT 1, and LG EMG was lower at EMGFT 2. EMGFT can be determined during a single treadmill running test, and EMGFT 1 may be the most appropriate method to estimate the muscle fatigue threshold during running. © 2015 Wiley Periodicals, Inc.

  17. Muscular co-operation during joint stabilisation, as reflected by EMG.

    Science.gov (United States)

    Kornecki, S; Kebel, A; Siemieński, A

    2001-05-01

    The experiment that was carried out consisted of subjects pushing an external object (a heavy pendulum) using stable and unstable handles of increasing mobility. Using this protocol it was possible to distinguish between the motor and stabilising functions of the muscles of the upper extremity. The motor functions were realised by the extensors of the upper extremity, whereas stabilising functions were effected by the muscles spanning the wrist joint. The experiment involved synchronised measurements of the electromyographic (EMG) activity of the muscles in question together with several mechanical quantities revealed against the external object: force, velocity and power. As a result, the instantaneous and global EMG contributions of the extensor and stabilising muscles were determined. It was found that it is the equilibrium state of the object being set in motion and not its mobility (expressed in terms of the number of degrees of freedom) that influences the forces produced by individual muscles. We also suggest that the realisation of stabilising functions by skeletal muscles is a necessary condition of performing any voluntary and co-ordinated movement.

  18. [Hip abduction force measured by a new method and its relation to EMG activity].

    Science.gov (United States)

    Murakami, K

    1989-11-01

    I measured hip abduction force using a new device of my own design and evaluated the correlation between hip abduction force and electromyographic (EMG) activity of the gluteus medius, gluteus maximus, rectus femoris and adductor longus in 20 normal adults. Hip abduction force showed a maximum value on starting and decreased during abduction of the hip joint. Durability, on the other hand, showed an increase. The attenuation curve was approximated to the exponential function A.e-Kt; A and l/k indicating maximum hip abduction force and durability, respectively. Maximum hip abduction force was about 20 kg and durability was about 160 seconds on starting hip abduction. The regression coefficient between hip abduction force and EMG activity of the gluteus medius, gluteus maximus, rectus femoris and adductor longus was 1.5, 06, 0.6 and 0.2 respectively. From these results, I concluded that although the gluteus medius plays the major role in hip abduction, the rectus femoris and gluteus maximus may act as stabilizers for maintaining the position of hip abduction.

  19. Fuel selection during intense shivering in humans: EMG pattern reflects carbohydrate oxidation

    Science.gov (United States)

    Haman, François; Legault, Stéphane R; Weber, Jean-Michel

    2004-01-01

    The thermogenic response of humans depends critically on the coordination of muscle fibre recruitment and oxidative fuel metabolism. The primary goal of this study was to determine whether the electromyographic (EMG) pattern of muscle recruitment could provide metabolic information on oxidative fuel selection during high-intensity shivering. EMG activity (of 8 large muscles) and fuel metabolism were monitored simultaneously in non-acclimatized adult men during high-intensity shivering. Even though acute cold exposure elicited similar changes in metabolic rate among subjects, lipid and carbohydrate use was very different. Depending on the subject, the cold-induced increase in carbohydrate (CHO) oxidation ranged between 2- and 8-fold, with CHO accounting for 33–78% of total heat production (Ḣprod), and lipids for 14–60% Ḣprod. This high variability in fuel selection was primarily explained by differences in ‘burst shivering’ rate, indicating that the recruitment of type II fibres plays a key role in orchestrating fuel selection. This study is the first to show that the pattern of muscle recruitment can provide quantitative information on energy metabolism. Future work should focus on the study of shivering bursts that may provide essential clues on what limits human survival in the cold. PMID:14742724

  20. An electromyographic study of dental work.

    Science.gov (United States)

    Milerad, E; Ericson, M O; Nisell, R; Kilbom, A

    1991-07-01

    Musculoskeletal disorders are common among dentists, and have been ascribed to the demands of high precision work and sustained static loading in the neck-shoulder region, combined with a flexed and rotated cervical spine. In order to determine muscular load levels during dentistry, activity in neck, shoulder, and arm muscles was recorded using an electromyography technique (EMG). Normalized mean, median, 10th and 90th percentile EMG amplitude levels (% maximal reference contraction, %max-RVC) were calculated during ordinary dental work. Among the muscles investigated, the trapezius muscle on both sides had the highest mean (the right trapezius 9.0% and the left 7.6% of max-RVC) and 10th percentile amplitude levels (both about 2% of max-RVC). The trapezius muscles showed similar myoelectric activity on the right and left side, probably because of similar muscular static load on the both sides. The right extensor carpi radialis muscle had a significantly higher muscular load level than the left one, possibly due to stabilization demands on the dominant wrist during demanding precision work. The infraspinatus muscle had low activity level on both sides, reflecting that the dentists worked with a small degree of arm elevation and external rotation. The dentistry work thus seems to generate relatively high muscular load on both trapezius and dominant extensor-carpi-radialis, and relatively low load on the infraspinatus muscle.

  1. A Study on EMG-based Biometrics

    Directory of Open Access Journals (Sweden)

    Jin Su Kim

    2017-05-01

    Full Text Available Biometrics is a technology that recognizes user's information by using unique physical features of his or her body such as face, fingerprint, and iris. It also uses behavioral features such as signature, electrocardiogram (ECG, electromyogram (EMG, and electroencephalogram (EEG. Among them, the EMG signal is a sign generated when the muscles move, which can be used in various fields such as motion recognition, personal identification, and disease diagnosis. In this paper, we analyze EMG-based biometrics and implement a motion recognition and personal identification system. The system extracted features using non-uniform filter bank and Waveform Length (WL, and reduces the dimension using Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA. Afterward, it classified the features using Euclidean Distance (ED, Support Vector Machine (SVM and K Nearest Neighbors (KNN. As a result of the motion recognition experiment, 95% of acquired EMG data and 84.66% of UCI data were obtained and as a result of the personal recognition experiment, 85% of acquired EMG data and 88.66% of UCI data were obtained.

  2. Electromyographic comparison of conventional machine strength training versus bodyweight exercises in patients with chronic stroke.

    Science.gov (United States)

    Vinstrup, Jonas; Calatayud, Joaquin; Jakobsen, Markus D; Sundstrup, Emil; Jay, Kenneth; Brandt, Mikkel; Zeeman, Peter; Jørgensen, Jørgen R; Andersen, Lars L

    2017-05-01

    To investigate whether bodyweight exercises can induce comparable levels of muscle activity as conventional machine exercises in chronic stroke patients. Eighteen patients performed three repetitions of bilateral- and unilateral machine leg press and the bodyweight exercises chair rise and hip thrust. Surface electromyography (EMG) was recorded from 10 lower extremity muscles and normalized to maximal EMG (nEMG) of the non-paretic leg. For the paretic leg, the bodyweight exercises showed comparable levels of nEMG in 6 out of 10 muscles compared with the bilateral leg press. Vastus lateralis nEMG was higher during bilateral leg press compared with hip thrust (38% [95% CI 33-42] vs. 10% [95% CI 6-15], p hip thrust (34% [95%CI 27-40] vs. 8% [95% CI 2-15], p < 0.0001). Unilateral leg press showed higher nEMG compared with bilateral leg press in biceps femoris (28% [95% CI 23-34] vs. 19% [95% CI 13-24], p = 0.0009), gluteus maximus (32% [95% CI 23-41] vs. 25% [95% CI 16-34], p < 0.05), and vastus medialis (42% [95% CI 36-48] vs. 34% [95% CI 27-40], p = 0.0013). In patients with chronic stroke, bodyweight exercises activate the majority of the lower limb muscles to comparable levels as bilateral leg press performed in machine. In addition, unilateral leg press was superior to the bilateral leg press and both bodyweight exercises.

  3. Effects of electromyographic and mechanomyographic biofeedback on upper trapezius muscle activity during standardized computer work

    DEFF Research Database (Denmark)

    Madeleine, Pascal; Vedsted, Pernille; Blangsted, Anne Katrine

    2006-01-01

    The purpose of this laboratory study was to investigate the effects of surface electromyography (EMG)- and mechanomyography (MMG)-based audio and visual biofeedback during computer work. Standardized computer work was performed for 3 min with/without time constraint and biofeedback in a randomize...... alternative to EMG in ergonomics. A lowering of the trapezius muscle activity may contribute to diminish the risk of work related musculoskeletal disorders development.......The purpose of this laboratory study was to investigate the effects of surface electromyography (EMG)- and mechanomyography (MMG)-based audio and visual biofeedback during computer work. Standardized computer work was performed for 3 min with/without time constraint and biofeedback in a randomized......) values as well as the work performance in terms of number of completed graph/mouse clicks/errors, the rating of perceived exertion (RPE) and the usefulness of the biofeedback were assessed. The duration of muscle activity above the threshold was significantly lower with MMG compared with EMG as source...

  4. An Embedded, Eight Channel, Noise Canceling, Wireless, Wearable sEMG Data Acquisition System With Adaptive Muscle Contraction Detection.

    Science.gov (United States)

    Ergeneci, Mert; Gokcesu, Kaan; Ertan, Erhan; Kosmas, Panagiotis

    2018-02-01

    Wearable technology has gained increasing popularity in the applications of healthcare, sports science, and biomedical engineering in recent years. Because of its convenient nature, the wearable technology is particularly useful in the acquisition of the physiological signals. Specifically, the (surface electromyography) sEMG systems, which measure the muscle activation potentials, greatly benefit from this technology in both clinical and industrial applications. However, the current wearable sEMG systems have several drawbacks including inefficient noise cancellation, insufficient measurement quality, and difficult integration to customized applications. Additionally, none of these sEMG data acquisition systems can detect sEMG signals (i.e., contractions), which provides a valuable environment for further studies such as human machine interaction, gesture recognition, and fatigue tracking. To this end, we introduce an embedded, eight channel, noise canceling, wireless, wearable sEMG data acquisition system with adaptive muscle contraction detection. Our design consists of two stages, which are the sEMG sensors and the multichannel data acquisition unit. For the first stage, we propose a low cost, dry, and active sEMG sensor that captures the muscle activation potentials, a data acquisition unit that evaluates these captured multichannel sEMG signals and transmits them to a user interface. In the data acquisition unit, the sEMG signals are processed through embedded, adaptive methods in order to reject the power line noise and detect the muscle contractions. Through extensive experiments, we demonstrate that our sEMG sensor outperforms a widely used commercially available product and our data acquisition system achieves 4.583 dB SNR gain with accuracy in the detection of the contractions.

  5. Effects of static stretching on the hamstrings-to-quadriceps ratio and electromyographic amplitude in men.

    Science.gov (United States)

    Costa, P B; Ryan, E D; Herda, T J; Defreitas, J M; Beck, T W; Cramer, J T

    2009-12-01

    The purpose of this study was to examine the effects of posterior thigh and leg stretching on leg flexion peak torque (PT), leg extension PT, the hamstrings-to-quadriceps (H:Q) ratio, and electromyographic (EMG) amplitude of the hamstrings and quadriceps in recreationally-active men. Fifteen men (mean age + or - SD = 22.0 + or - 4.4 years; body mass = 82.7 + or - 16.1 kg; height = 173.1 + or - 6.8 cm) performed three maximal voluntary concentric isokinetic leg extension and flexion muscle actions at three randomly ordered angular velocities (60, 180, and 300 degrees x s(-1)) before and after hamstring and calf static stretching. The stretching protocol consisted of 1 unassisted and 3 assisted static stretching exercises designed to stretch the posterior muscles of the thigh and leg. Four repetitions of each stretch were held for 30 s with 20-s rest between repetitions. These findings indicated no significant (P>0.05) stretching-induced changes in leg flexion PT, leg extension PT, or EMG amplitude at 60, 180, or 300 degrees .s-1. However, the non-significant (P>0.05) 2-4% increases in leg extension PT combined with the non-significant (P>0.05) 1-2% decreases in leg flexion PT resulted in the significant (P ratio from pre- to post-stretching for all three velocities. These findings suggested that static stretching of the hamstrings and calf muscles may decrease the H:Q ratio. These results may be useful for athletic trainers, physical therapists, and other allied health professionals who may use the H:Q ratio as a clinical assessment.

  6. Effect of occlusal vertical dimension on swallowing patterns and perioral electromyographic activity.

    Science.gov (United States)

    MacAvoy, S K; Jack, H C; Kieser, J; Farella, M

    2016-07-01

    Abnormal swallow patterns have been associated with specific dentofacial traits, such as an anterior open bite, but the cause-effect relationship between swallowing and malocclusion remains highly controversial. The aim of this research was to determine the effects of acute change in occlusal vertical dimension (OVD) on intraoral pressure swallow patterns and perioral electromyographic activity (EMG) during swallowing. Ten volunteers (five female, five male; 27-32 years) repeated standardised swallowing tasks as the OVD was progressively increased using mandibular trays of different heights. Standardised swallowing tasks were performed repetitively with each tray in place. Individual swallowing waveforms were quantitatively and qualitatively analysed. Peak pressure, swallow duration, time to peak pressure and lip EMG peak activity were assessed for each swallow. Data were analysed using mixed-model analysis. As OVD increased, lip peak pressure during swallowing increased almost threefold (+2·1 kPa; P ≤ 0·001), whereas swallow duration increased by 12·7 per cent (+160 ms; P = 0·01) at lip level and by 26·4 per cent (+270 ms; P < 0·001) at tongue level. Perioral muscle activity during swallows increased by 43·7 per cent (P ≤ 0·01) up to the OVD where resting lip seal was not attainable. Swallowing waveforms varied markedly between individuals, but interindividual waveforms were only minimally affected. The adaptive response and the waveform similarities associated with OVD variation supports the existence of a central control mechanism for swallowing, which may be modified by peripheral inputs. © 2016 John Wiley & Sons Ltd.

  7. EMG analysis of human inspiratory muscle resistance to fatigue during exercise.

    Science.gov (United States)

    Segizbaeva, M O; Donina, Zh A; Timofeev, N N; Korolyov, Yu N; Golubev, V N; Aleksandrova, N P

    2013-01-01

    The aim of this study was to characterize the pattern of inspiratory muscle fatigue and to assess the resistance to fatigue of the diaphragm (D), parasternal (PS), sternocleidomastoid (SCM), and scalene (SC) muscles. Nine healthy, untrained male subjects participated in this study. Electromyographic activity (EMG) of D, PS, SCM, and SC was recorded during an incremental cycling test to exhaustion (workload of 1.0 W/kg with 0.5 W/kg increments every 5 min). The before-to-after exercise measurements of maximal inspiratory pressure (MIP) and EMG power spectrum changes were performed. The maximal inspiratory pressure declined about 8.1 % after exercise compared with that in the control condition (124.3 ± 8.5 vs. 114.2 ± 8.9 cmH2O) (P > 0.05), whereas the peak magnitude of integrated electrical activity of D, PS, SCM, and SC during the post-exercise Müller maneuver was significantly greater in all subjects than that pre-exercise. The extent of inspiratory muscles fatigue was evaluated by analysis of a shift in centroid frequency (fc) of EMG power spectrum. Exercise-induced D fatigue was present in three subjects and PS fatigue was another in two; whereas both D and PC fatigue were observed in four subjects. All subjects demonstrated a significant reduction in fc of SCM and SC. Results indicate that early signs of the fatiguing process might be detected in the D, PS, SCM, and SC muscles during exercise to exhaustion. Fatigue of either D or PS muscles develops selectively or together during exhaustive exercise, depending on the recruitment pattern of respiratory muscles. Accessory inspiratory muscles of the neck are less resistant to fatigue compared with the D and PS muscles.

  8. Electromyographic bridge for promoting the recovery of hand movements in subacute stroke patients: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Yu-Xuan Zhou

    2017-08-01

    Full Text Available Objective: The electromyographic bridge (EMGB detects surface electromyographic signals from a non-paretic limb. It then generates electric pulse trains according to the electromyographic time domain features, which can be used to stimulate a paralysed or paretic limb in real time. This strategy can be used for the contralateral control of neuromuscular electrical stimulation (NMES to improve motor function after stroke. The aim of this study was to compare the treat-ment effects of EMGB vs cyclic NMES on wrist and finger impairments in subacute stroke patients. Methods: A total of 42 hemiplegic patients within 6 months of their cerebrovascular accidents were randomly assigned to 4-week treatments with EMGB or cyclic NMES. Each group underwent a standard rehabilitation programme and 10 sessions per week of hand training with EMGB or cyclic NMES. Outcome measures were: Brunnstrom stage, upper extremity components of the Fugl-Meyer Assessment, Motor Status Scale, voluntary surface electromyographic ratio and active range of motion of the wrist and finger joints. Results: The EMGB group showed significantly greater improvements than the cyclic NMES group on the following measures: Brunnstrom stages for the hand, upper extremity – Fugl-Meyer Assessment, Motor Status Scale, and the voluntary surface electromyographic ratio of wrist and finger extensors. Eleven and 4 participants of the EMGB group who had no active wrist and finger movements, respectively, at the start of the treatment could perform measurable wrist and finger extensions after EMGB training. The corresponding numbers in the cyclic NMES group were only 4 and 1. Conclusion: In the present group of subacute stroke patients, the results favour EMGB over cyclic NMES for augmenting the recovery of volitional wrist and finger motion.

  9. Electromyographic bridge for promoting the recovery of hand movements in subacute stroke patients: A randomized controlled trial.

    Science.gov (United States)

    Zhou, Yu-Xuan; Xia, Yang; Huang, Jia; Wang, Hai-Peng; Bao, Xue-Liang; Bi, Zheng-Yang; Chen, Xiao-Bing; Gao, Yu-Jie; Lü, Xiao-Ying; Wang, Zhi-Gong

    2017-08-31

    The electromyographic bridge (EMGB) detects surface electromyographic signals from a non-paretic limb. It then generates electric pulse trains according to the electromyographic time domain features, which can be used to stimulate a paralysed or paretic limb in real time. This strategy can be used for the contralateral control of neuromuscular electrical stimulation (NMES) to improve motor function after stroke. The aim of this study was to compare the treat-ment effects of EMGB vs cyclic NMES on wrist and finger impairments in subacute stroke patients. A total of 42 hemiplegic patients within 6 months of their cerebrovascular accidents were randomly assigned to 4-week treatments with EMGB or cyclic NMES. Each group underwent a standard rehabilitation programme and 10 sessions per week of hand training with EMGB or cyclic NMES. Outcome measures were: Brunnstrom stage, upper extremity components of the Fugl-Meyer Assessment, Motor Status Scale, voluntary surface electromyographic ratio and active range of motion of the wrist and finger joints. The EMGB group showed significantly greater improvements than the cyclic NMES group on the following measures: Brunnstrom stages for the hand, upper extremity - Fugl-Meyer Assessment, Motor Status Scale, and the voluntary surface electromyographic ratio of wrist and finger extensors. Eleven and 4 participants of the EMGB group who had no active wrist and finger movements, respectively, at the start of the treatment could perform measurable wrist and finger extensions after EMGB training. The corresponding numbers in the cyclic NMES group were only 4 and 1. In the present group of subacute stroke patients, the results favour EMGB over cyclic NMES for augmenting the recovery of volitional wrist and finger motion.

  10. Static optimization of muscle forces during gait in comparison to EMG-to-force processing approach.

    Science.gov (United States)

    Heintz, Sofia; Gutierrez-Farewik, Elena M

    2007-07-01

    models can arguably be more accurate than from those obtained from surface EMG during gait, though magnitude must still be validated.

  11. Electromyographic activity of hand muscles in a motor coordination game: effect of incentive scheme and its relation with social capital.

    Science.gov (United States)

    Censolo, Roberto; Craighero, Laila; Ponti, Giovanni; Rizzo, Leonzio; Canto, Rosario; Fadiga, Luciano

    2011-03-25

    A vast body of social and cognitive psychology studies in humans reports evidence that external rewards, typically monetary ones, undermine intrinsic motivation. These findings challenge the standard selfish-rationality assumption at the core of economic reasoning. In the present work we aimed at investigating whether the different modulation of a given monetary reward automatically and unconsciously affects effort and performance of participants involved in a game devoid of visual and verbal interaction and without any perspective-taking activity. Twelve pairs of participants were submitted to a simple motor coordination game while recording the electromyographic activity of First Dorsal Interosseus (FDI), the muscle mainly involved in the task. EMG data show a clear effect of alternative rewards strategies on subjects' motor behavior. Moreover, participants' stock of relevant past social experiences, measured by a specifically designed questionnaire, was significantly correlated with EMG activity, showing that only low social capital subjects responded to monetary incentives consistently with a standard rationality prediction. Our findings show that the effect of extrinsic motivations on performance may arise outside social contexts involving complex cognitive processes due to conscious perspective-taking activity. More importantly, the peculiar performance of low social capital individuals, in agreement with standard economic reasoning, adds to the knowledge of the circumstances that makes the crowding out/in of intrinsic motivation likely to occur. This may help in improving the prediction and accuracy of economic models and reconcile this puzzling effect of external incentives with economic theory.

  12. Evaluation of electromyographic activity and heart rate responses to isometric exercise. The role played by muscular mass and type

    Directory of Open Access Journals (Sweden)

    E. Silva

    1999-01-01

    Full Text Available The purpose of the present study was to examine the relationship between the electromyographic (EMG activity and heart rate (HR responses induced by isometric exercise performed by knee extension (KE and flexion (KF in men. Fifteen healthy male subjects, 21 ± 1.3 years (mean ± SD, were submitted to KE and KF isometric exercise tests at 100% of maximal voluntary contraction (MVC. The exercises were performed with one leg (right or left and with two legs simultaneously, for 10 s in the sitting position with the hip and knee flexed at 90o. EMG activity (root mean square values and HR (beats/min were recorded simultaneously both at rest and throughout the sustained contraction. The HR responses to isometric exercise in KE and KF were similar when performed with one and two legs. However, the HR increase was always significantly higher in KE than KF (P0.05 and KF (r = 0.15, P>0.05 contractions were not significant. These results suggest that the predominant mechanism responsible for the larger increase in HR response to KE as compared to KF in our study could be dependent on qualitative and quantitative differences in the fiber type composition found in each muscle group. This mechanism seems to demand a higher activation of motor units with a corresponding increase in central command to the cardiovascular centers that modulate HR control.

  13. The Response of Hyperkinesis to EMG Biofeedback.

    Science.gov (United States)

    Haight, Maryellen J.; And Others

    A study was conducted involving eight hyperkinetic males (11-15 years old) to determine if Ss receiving electromyography (EMG) biofeedback training would show a reduction in frontalis muscle tension, hyperactivity, and lability, and increases in self-esteem and visual and auditory attention span. Individual 45- and 30-minute relaxation exercises…

  14. Hedonic reactivity to visual and olfactory cues: rapid facial electromyographic reactions are altered in anorexia nervosa.

    Science.gov (United States)

    Soussignan, Robert; Schaal, Benoist; Rigaud, Daniel; Royet, Jean-Pierre; Jiang, Tao

    2011-03-01

    Though it has been suggested that hedonic processing is altered in anorexia nervosa (AN), few studies have used objective measures to assess affective processes in this eating disorder. Accordingly, we investigated facial electromyographic, autonomic and subjective reactivity to the smell and sight of food and non-food stimuli, and assessed more particularly rapid facial reactions reflecting automatic processing of pleasantness. AN and healthy control (HC) women were exposed, before and after a standardized lunch, to pictures and odorants of foods differing in energy density, as well as to non-food sensory cues. Whereas the temporal profile of zygomatic activity in AN patients was typified by a fast drop to sensory cues within the 1000 ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800-1000 ms time window. In contrast, pleasantness ratings discriminated the two groups only for high energy density food cues suggesting a partial dissociation between objective and subjective measures of hedonic processes in AN patients. The findings suggest that the automatic processing of pleasantness might be altered in AN, with the sensitivity to reward being modulated by controlled processes. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. A hybrid brain-computer interface based on the fusion of electroencephalographic and electromyographic activities

    Science.gov (United States)

    Leeb, Robert; Sagha, Hesam; Chavarriaga, Ricardo; Millán, José del R.

    2011-04-01

    Hybrid brain-computer interfaces (BCIs) are representing a recent approach to develop practical BCIs. In such a system disabled users are able to use all their remaining functionalities as control possibilities in parallel with the BCI. Sometimes these people have residual activity of their muscles. Therefore, in the presented hybrid BCI framework we want to explore the parallel usage of electroencephalographic (EEG) and electromyographic (EMG) activity, whereby the control abilities of both channels are fused. Results showed that the participants could achieve a good control of their hybrid BCI independently of their level of muscular fatigue. Thereby the multimodal fusion approach of muscular and brain activity yielded better and more stable performance compared to the single conditions. Even in the case of an increasing muscular fatigue a good control (moderate and graceful degradation of the performance compared to the non-fatigued case) and a smooth handover could be achieved. Therefore, such systems allow the users a very reliable hybrid BCI control although they are getting more and more exhausted or fatigued during the day.

  16. Electromyographic activity of masticatory muscles in elderly women – a pilot study

    Directory of Open Access Journals (Sweden)

    Gaszynska E

    2017-01-01

    Full Text Available Ewelina Gaszynska,1 Karolina Kopacz,2 Magdalena Fronczek-Wojciechowska,2 Gianluca Padula,2 Franciszek Szatko1 1Department of Hygiene and Health Promotion, 2Academic Laboratory of Movement and Human Physical Performance “DynamoLab”, Medical University of Lodz, Lodz, PolandObjectives: To evaluate the effect of age and chosen factors related to aging such as dentition, muscle strength, and nutrition on masticatory muscles electromyographic activity during chewing in healthy elderly women.Background: With longer lifespan there is a need for maintaining optimal quality of life and health in older age. Skeletal muscle strength deteriorates in older age. This deterioration is also observed within masticatory muscles.Methods: A total of 30 women, aged 68–92 years, were included in the study: 10 indivi­duals had natural functional dentition, 10 were missing posterior teeth in the upper and lower jaw reconstructed with removable partial dentures, and 10 were edontoulous, using complete removable dentures. Surface electromyography was performed to evaluate masticatory muscles activity. Afterwards, measurement of masseter thickness with ultrasound imaging was performed, body mass index and body cell mass index were calculated, and isometric handgrip strength was measured.Results: Isometric maximal voluntary contraction decreased in active masseters with increasing age and in active and passive temporalis muscles with increasing age and increasing body mass index. In active masseter, mean electromyographic activity during the sequence (time from the start of chewing till the end when the test food became ready to swallow decreased with increasing age and during the cycle (single bite time decreased with increasing age and increasing body mass index. In active and passive temporalis muscles, mean electromyographic activity during the sequence and the cycle decreased with increasing age, increasing body mass index, and loss of natural dentition

  17. Effect of conventional TENS on pain and electromyographic activity of masticatory muscles in TMD patients Efeito da TENS convencional sobre a dor e a atividade eletromiográfica dos músculos mastigatórios em pacientes com DTM

    Directory of Open Access Journals (Sweden)

    Delaine Rodrigues

    2004-12-01

    Full Text Available Temporomandibular disorders (TMD are characterized by several signs and symptoms, such as pain and changes in the electrical activity of masticatory muscles. Considering that transcutaneous electrical nerve stimulation (TENS is a resource indicated to promote analgesia, the objective of this study was to evaluate the effect of TENS on pain and electromyographic (EMG activity of the jaw elevator muscles in TMD patients. This study evaluated 35 female volunteers: 19 TMD patients (mean age = 23.04 ± 3.5 and 16 normal subjects (mean age = 23.3 ± 3.0. Transcutaneous electrical nerve stimulation (conventional mode, 150 Hz was applied once to each group for 45 minutes. Surface electromyography (gain of 100 times and 1 kHz sampling frequency and the visual analogue scale (VAS were applied before and immediately after TENS application. Both VAS data and root mean square (RMS values were analyzed using Student's t-test. The TMD group, compared to the control group, showed higher EMG activity of the jaw elevator muscles at rest. No difference was observed between the groups regarding maximum voluntary clenching (MVC. In TMD patients, TENS reduced both pain and EMG activity of the anterior portion of the temporal muscle, increasing the activity of the masseter muscles during MVC. It is possible to conclude that a single TENS application is effective in pain reduction. However, it does not act homogeneously on the features of the electric activity of the muscles evaluated.A desordem temporomandibular (DTM é caracterizada por diversos sinais e sintomas, como dor e alteração do sinal eletromiográfico dos músculos da mastigação. Considerando que a estimulação elétrica nervosa transcutânea (TENS é um recurso indicado para promover analgesia, o objetivo deste trabalho foi avaliar o efeito da TENS na dor e na atividade eletromiográfica (EMG dos músculos elevadores da mandíbula em indivíduos com DTM. Foram selecionados 35 voluntários do sexo

  18. A Wireless sEMG Recording System and Its Application to Muscle Fatigue Detection

    Science.gov (United States)

    Chang, Kang-Ming; Liu, Shin-Hong; Wu, Xuan-Han

    2012-01-01

    Surface electromyography (sEMG) is an important measurement for monitoring exercise and fitness. Because if its high sampling frequency requirement, wireless transmission of sEMG data is a challenge. In this article a wireless sEMG measurement system with a sampling frequency of 2 KHz is developed based upon a MSP 430 microcontroller and Bluetooth transmission. Standard isotonic and isometric muscle contraction are clearly represented in the receiving user interface. Muscle fatigue detection is an important application of sEMG. Traditional muscle fatigue is detected from the median frequency of the sEMG power spectrum. The regression slope of the linear regression of median frequency is an important muscle fatigue index. A more negative slope value represents a higher muscle fatigue condition. To test the system performance, muscle fatigue detection was examined by having subjects run on a pedaled-multifunctional elliptical trainer for approximately 30 minutes at three loading levels. Ten subjects underwent a total of 60 exercise sessions to provide the experimental data. Results showed that the regression slope gradually decreases as expected, and there is a significant gender difference. PMID:22368481

  19. A Wireless sEMG Recording System and Its Application to Muscle Fatigue Detection

    Directory of Open Access Journals (Sweden)

    Xuan-Han Wu

    2012-01-01

    Full Text Available Surface electromyography (sEMG is an important measurement for monitoring exercise and fitness. Because if its high sampling frequency requirement, wireless transmission of sEMG data is a challenge. In this article a wireless sEMG measurement system with a sampling frequency of 2 KHz is developed based upon a MSP 430 microcontroller and Bluetooth transmission. Standard isotonic and isometric muscle contraction are clearly represented in the receiving user interface. Muscle fatigue detection is an important application of sEMG. Traditional muscle fatigue is detected from the median frequency of the sEMG power spectrum. The regression slope of the linear regression of median frequency is an important muscle fatigue index. A more negative slope value represents a higher muscle fatigue condition. To test the system performance, muscle fatigue detection was examined by having subjects run on a pedaled-multifunctional elliptical trainer for approximately 30 minutes at three loading levels. Ten subjects underwent a total of 60 exercise sessions to provide the experimental data. Results showed that the regression slope gradually decreases as expected, and there is a significant gender difference.

  20. The champagne toast position isolates the supraspinatus better than the Jobe test: an electromyographic study of shoulder physical examination tests.

    Science.gov (United States)

    Chalmers, Peter N; Cvetanovich, Gregory L; Kupfer, Noam; Wimmer, Markus A; Verma, Nikhil N; Cole, Brian J; Romeo, Anthony A; Nicholson, Gregory P

    2016-02-01

    While Jobe's test is widely used, it does not isolate supraspinatus activity. Our purpose was to examine the electromyographic (EMG) activity within the supraspinatus and deltoid with resisted abduction to determine the shoulder position that best isolates the activity of the supraspinatus. We performed EMG analysis of the supraspinatus, anterior head of the deltoid, and middle head of the deltoid in 10 normal volunteers. We measured EMG activity during resisted shoulder abduction in the scapular plane to both manual resistance and a standardized load in varying degrees of abduction and rotation. To determine which position best isolates supraspinatus activity, the ratio of supraspinatus to deltoid activity (S:D) was calculated for each position. Results were analyzed with a repeated-measures analysis of variance with Bonferroni correction. The posterior deltoid was excluded as it serves mostly to extend and externally rotate. Our study confirmed Jobe's findings of maximal supraspinatus activity at 90° of abduction. However, decreasing abduction significantly increased S:D for both resisted manual testing and testing against a standardized load (P = .002 and .001, respectively). The greatest S:D ratio (4.6 ± 3.4 for standardized load testing) was seen at the "champagne toast" position, i.e., 30° of abduction, mild external rotation, 30° of flexion, and 90° of elbow flexion. The smallest ratio (0.8 ± 0.6) was seen at Jobe's position. Testing of abduction strength in the champagne toast position, i.e., 30° of abduction, mild external rotation, and 30° of flexion, better isolates the activity of the supraspinatus from the deltoid than Jobe's "empty can" position. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  1. Articulate torque and electromyographic activity of biceps femoris and semitendinosus muscles during isokinetic knee flexion movements in soccer athletes

    Directory of Open Access Journals (Sweden)

    Eduardo Bodnariuc Fontes

    2007-09-01

    Full Text Available The objective of the present study was to analyze the articulate torque (TO and the electromyographic activity (EMG of soccer athlete’s long head Biceps Femoris (BF and Semitendinosus (ST muscles during isokinetic knee fl exion movements (concentric-CON and eccentric-ECC actions at differing velocities, carried out in the ventral decubitus position. Fourteen soccer players aged 19 and 20 years old (71.2 ± 6.5 kg, 176.6 ± 6.4 cm were enrolled from the Associação Atlética Ponte Preta under- 20 team. They followed a protocol specifying 5 repetitions of fl exion (CON and ECC action of the knee at three velocities (60, 180 and 300º/s at random. The recovery interval between series adopted was 3 minutes. EMG Activity was recorded using surface electrodes and data were expressed in terms of root mean squares (RMS. Statistical analysis employed analysis of variance (Friedman test for repeated measures followed by the Wilcoxon test when necessary, with the level of signifi cance set at P ABSTRACT O objetivo do presente estudo foi analisar o torque articular (TO e a atividade eletromiográfi ca (EMG dos músculos Bíceps Femoral (BF cabeça longa e semitendíneo (ST durante movimentos isocinéticos de fl exão do joelho (ação concêntrica-CON e excêntrica-EXC, em diferentes velocidades de execução, na posição de decúbito ventral em atletas de futebol. Fizeram parte do estudo 14 atletas de futebol da equipe sub-20, da Associação Atlética Ponte Preta, com idade entre 19 e 20 anos (71,24 ± 6,53 kg, 176,59 ± 6,44 cm. Os atletas realizaram uma série de cinco repetições de fl exão (ação CON e EXC do joelho, em 3 velocidades (60, 180 e 300°/s, defi nidas anteriormente aleatoriamente. O intervalo de recuperação adotado entre as séries foi de 3 minutos. A atividade EMG foi coletada, utilizando-se eletrodos de superfície e os dados foram expressos em root mean square (RMS. Para análise estatística, foi empregada a análise de vari

  2. A canonical correlation analysis based EMG classification algorithm for eliminating electrode shift effect.

    Science.gov (United States)

    Zhe Fan; Zhong Wang; Guanglin Li; Ruomei Wang

    2016-08-01

    Motion classification system based on surface Electromyography (sEMG) pattern recognition has achieved good results in experimental condition. But it is still a challenge for clinical implement and practical application. Many factors contribute to the difficulty of clinical use of the EMG based dexterous control. The most obvious and important is the noise in the EMG signal caused by electrode shift, muscle fatigue, motion artifact, inherent instability of signal and biological signals such as Electrocardiogram. In this paper, a novel method based on Canonical Correlation Analysis (CCA) was developed to eliminate the reduction of classification accuracy caused by electrode shift. The average classification accuracy of our method were above 95% for the healthy subjects. In the process, we validated the influence of electrode shift on motion classification accuracy and discovered the strong correlation with correlation coefficient of >0.9 between shift position data and normal position data.

  3. EMG monitoring during functional non-surgical therapy of Achilles tendon rupture.

    Science.gov (United States)

    Hüfner, Tobias; Wohifarth, Kai; Fink, Matthias; Thermann, H; Rollnik, Jens D

    2002-07-01

    After surgical therapy of Achilles tendon rupture, neuromuscular changes may persist, even one year after surgery. We were interested whether these changes are also evident following a non-surgical functional therapy (Variostabil therapy boot/Adidas). Twenty-one patients with complete Achilles tendon rupture were enrolled in the study (mean age 38.5 years, range 24 to 60; 18 men, three women) and followed-up clinically and with surface EMG of the gastrocnemius muscles after four, eight, 12 weeks, and one year after rupture. EMG differences between the affected and non-affected side could only be observed at baseline and after four weeks following Achilles tendon rupture. The results from our study show that EMG changes are not found following non-surgical functional therapy.

  4. fMRI analysis for motor paradigms using EMG-based designs: a validation study

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; Renken, Remco; de Jong, Bauke M.; Hoogduin, Johannes M.; Tijssen, Marina A. J.; Maurits, Natasha M.

    2007-01-01

    The goal of the present validation study is to show that continuous surface EMG recorded simultaneously with 3T fMRI can be used to identify local brain activity related to (1) motor tasks, and to (2) muscle activity independently of a specific motor task, i.e. spontaneous (abnormal) movements. Five

  5. FMRl analysis for motor paradigms using EMG-Based designs : A validation study

    NARCIS (Netherlands)

    Van Rootselaar, Anne-Fleur; Renken, Remco; De Jong, Bauke M.; Hoogduin, Johannes M.; Tijssen, Marina A. J.; Maurits, Natasha M.

    2007-01-01

    The goal of the present validation study is to show that continuous surface EMG recorded simultaneously with 3T fMRI can be used to identify local brain activity related to (1) motor tasks, and to (2) muscle activity independently of a specific motor task, i.e. spontaneous (abnormal) movements. Five

  6. EMGAN: A computer program for time and frequency domain reduction of electromyographic data

    Science.gov (United States)

    Hursta, W. N.

    1975-01-01

    An experiment in electromyography utilizing surface electrode techniques was developed for the Apollo-Soyuz test project. This report describes the computer program, EMGAN, which was written to provide first order data reduction for the experiment. EMG signals are produced by the membrane depolarization of muscle fibers during a muscle contraction. Surface electrodes detect a spatially summated signal from a large number of muscle fibers commonly called an interference pattern. An interference pattern is usually so complex that analysis through signal morphology is extremely difficult if not impossible. It has become common to process EMG interference patterns in the frequency domain. Muscle fatigue and certain myopathic conditions are recognized through changes in muscle frequency spectra.

  7. Active pauses induce more variable electromyographic pattern of the trapezius muscle activity during computer work

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    , with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 2 min at two different work paces (low/high). Bipolar SEMG from four parts of the trapezius muscle was recorded. The relative rest time was higher for the lower parts compared with the upper......The aim of this laboratory study was to evaluate effects of active and passive pauses and investigate the distribution of the trapezius surface electromyographic (SEMG) activity during computer mouse work. Twelve healthy male subjects performed four sessions of computer work for 10 min in one day...... of the trapezius (pwork with active pause compared with passive one (p

  8. An electromyographic study to assess the minimal time duration for using the splint to raise the vertical dimension in patients with generalized attrition of teeth

    Directory of Open Access Journals (Sweden)

    Aditi Nanda

    2011-01-01

    Full Text Available Background: To investigate the effect of restoration of lost vertical by centric stabilizing splint on electromyographic (EMG activity of masseter and anterior temporalis muscles bilaterally in patients with generalized attrition of teeth. Materials and Methods: EMG activity of anterior temporalis and masseter muscle was recorded bilaterally for 10 patients whose vertical was restored with centric stabilizing splint. The recording was done at postural rest position and in maximum voluntary clenching for each subject before the start of treatment, immediately after placement of splint and at subsequent recall visits, with splint and without the splint. Results: The EMG activity at postural rest position (PRP and maximum voluntary clench (MVC decreased till 1 month for both the muscles. In the third month, an increase in muscle activity toward normalization was noted at PRP, both with and without splint. At MVC in the third month, the muscle activity without splint decreased significantly as compared to pretreatment values for anterior temporalis and masseter, while with the splint an increase was seen beyond the pretreatment values. Conclusion: A definite response of anterior temporalis and masseter muscle was observed over a period of 3 months. This is suggestive that the reversible increase in vertical prior to irreversible intervention must be carried out for a minimum of 3 months to achieve neuromuscular deprogramming. This allows the muscle to get adapted to the new postural position and attain stability in occlusion following splint therapy.

  9. Modulation of EMG-EMG Coherence in a Choice Stepping Task

    Directory of Open Access Journals (Sweden)

    Ippei Nojima

    2018-02-01

    Full Text Available The voluntary step execution task is a popular measure for identifying fall risks among elderly individuals in the community setting because most falls have been reported to occur during movement. However, the neurophysiological functions during this movement are not entirely understood. Here, we used electromyography (EMG to explore the relationship between EMG-EMG coherence, which reflects common oscillatory drive to motoneurons, and motor performance associated with stepping tasks: simple reaction time (SRT and choice reaction time (CRT tasks. Ten healthy elderly adults participated in the study. Participants took a single step forward in response to a visual imperative stimulus. EMG-EMG coherence was analyzed for 1000 ms before the presentation of the stimulus (stationary standing position from proximal and distal tibialis anterior (TA and soleus (SOL muscles. The main result showed that all paired EMG-EMG coherences in the alpha and beta frequency bands were greater in the SRT than the CRT task. This finding suggests that the common oscillatory drive to the motoneurons during the SRT task occurred prior to taking a step, whereas the lower value of corticospinal activity during the CRT task prior to taking a step may indicate an involvement of inhibitory activity, which is consistent with observations from our previous study (Watanabe et al., 2016. Furthermore, the beta band coherence in intramuscular TA tended to positively correlate with the number of performance errors that are associated with fall risks in the CRT task, suggesting that a reduction in the inhibitory activity may result in a decrease of stepping performance. These findings could advance the understanding of the neurophysiological features of postural adjustments in elderly individuals.

  10. EMG-Based Continuous and Simultaneous Estimation of Arm Kinematics in Able-Bodied Individuals and Stroke Survivors

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2017-08-01

    Full Text Available Among the potential biological signals for human-machine interactions (brain, nerve, and muscle signals, electromyography (EMG widely used in clinical setting can be obtained non-invasively as motor commands to control movements. The aim of this study was to develop a model for continuous and simultaneous decoding of multi-joint dynamic arm movements based on multi-channel surface EMG signals crossing the joints, leading to application of myoelectrically controlled exoskeleton robots for upper-limb rehabilitation. Twenty subjects were recruited for this study including 10 stroke subjects and 10 able-bodied subjects. The subjects performed free arm reaching movements in the horizontal plane with an exoskeleton robot. The shoulder, elbow and wrist movements and surface EMG signals from six muscles crossing the three joints were recorded. A non-linear autoregressive exogenous (NARX model was developed to continuously decode the shoulder, elbow and wrist movements based solely on the EMG signals. The shoulder, elbow and wrist movements were decoded accurately based only on the EMG inputs in all the subjects, with the variance accounted for (VAF > 98% for all three joints. The proposed approach is capable of simultaneously and continuously decoding multi-joint movements of the human arm by taking into account the non-linear mappings between the muscle EMGs and joint movements, which may provide less effortful control of robotic exoskeletons for rehabilitation training of individuals with neurological disorders and arm impairment.

  11. EMG-Based Continuous and Simultaneous Estimation of Arm Kinematics in Able-Bodied Individuals and Stroke Survivors

    Science.gov (United States)

    Liu, Jie; Kang, Sang Hoon; Xu, Dali; Ren, Yupeng; Lee, Song Joo; Zhang, Li-Qun

    2017-01-01

    Among the potential biological signals for human-machine interactions (brain, nerve, and muscle signals), electromyography (EMG) widely used in clinical setting can be obtained non-invasively as motor commands to control movements. The aim of this study was to develop a model for continuous and simultaneous decoding of multi-joint dynamic arm movements based on multi-channel surface EMG signals crossing the joints, leading to application of myoelectrically controlled exoskeleton robots for upper-limb rehabilitation. Twenty subjects were recruited for this study including 10 stroke subjects and 10 able-bodied subjects. The subjects performed free arm reaching movements in the horizontal plane with an exoskeleton robot. The shoulder, elbow and wrist movements and surface EMG signals from six muscles crossing the three joints were recorded. A non-linear autoregressive exogenous (NARX) model was developed to continuously decode the shoulder, elbow and wrist movements based solely on the EMG signals. The shoulder, elbow and wrist movements were decoded accurately based only on the EMG inputs in all the subjects, with the variance accounted for (VAF) > 98% for all three joints. The proposed approach is capable of simultaneously and continuously decoding multi-joint movements of the human arm by taking into account the non-linear mappings between the muscle EMGs and joint movements, which may provide less effortful control of robotic exoskeletons for rehabilitation training of individuals with neurological disorders and arm impairment. PMID:28890685

  12. Young, healthy subjects can reduce the activity of calf muscles when provided with EMG biofeedback in upright stance

    Directory of Open Access Journals (Sweden)

    Taian M. Vieira

    2016-04-01

    Full Text Available Recent evidence suggests the minimisation of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimising the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimise the level of muscle activation during standing without increasing the excursion of the centre of pressure (CoP. CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from ten healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects’ responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P<0.05 and an increase in tibialis anterior EMG (~10%; P<0.05. Furthermore, CoP mean position significantly shifted backward (~30 mm. In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at

  13. A motion-classification strategy based on sEMG-EEG signal combination for upper-limb amputees.

    Science.gov (United States)

    Li, Xiangxin; Samuel, Oluwarotimi Williams; Zhang, Xu; Wang, Hui; Fang, Peng; Li, Guanglin

    2017-01-07

    Most of the modern motorized prostheses are controlled with the surface electromyography (sEMG) recorded on the residual muscles of amputated limbs. However, the residual muscles are usually limited, especially after above-elbow amputations, which would not provide enough sEMG for the control of prostheses with multiple degrees of freedom. Signal fusion is a possible approach to solve the problem of insufficient control commands, where some non-EMG signals are combined with sEMG signals to provide sufficient information for motion intension decoding. In this study, a motion-classification method that combines sEMG and electroencephalography (EEG) signals were proposed and investigated, in order to improve the control performance of upper-limb prostheses. Four transhumeral amputees without any form of neurological disease were recruited in the experiments. Five motion classes including hand-open, hand-close, wrist-pronation, wrist-supination, and no-movement were specified. During the motion performances, sEMG and EEG signals were simultaneously acquired from the skin surface and scalp of the amputees, respectively. The two types of signals were independently preprocessed and then combined as a parallel control input. Four time-domain features were extracted and fed into a classifier trained by the Linear Discriminant Analysis (LDA) algorithm for motion recognition. In addition, channel selections were performed by using the Sequential Forward Selection (SFS) algorithm to optimize the performance of the proposed method. The classification performance achieved by the fusion of sEMG and EEG signals was significantly better than that obtained by single signal source of either sEMG or EEG. An increment of more than 14% in classification accuracy was achieved when using a combination of 32-channel sEMG and 64-channel EEG. Furthermore, based on the SFS algorithm, two optimized electrode arrangements (10-channel sEMG + 10-channel EEG, 10-channel sEMG + 20-channel

  14. Ulnar Nerve Conduction Block Using Surface Kilohertz Frequency Alternating Current: A Feasibility Study.

    Science.gov (United States)

    Springer, Shmuel; Kozol, Zvi; Reznic, Zvi

    2018-03-08

    The aim of this study was to test the effects of kilohertz frequency alternating current (KHFAC) surface stimulation applied to the ulnar nerve on force and myoelectrical activity of the abductor digiti minimi (ADM) muscle. Eighteen healthy volunteers (age: 27.6 ± 7.9 years; 10 males, 8 females) were included in the study. Each subject participated in one session during which a biphasic 7 kHz rectangular pulse was delivered above the medial epicondyle of the humerus to induce ulnar nerve blocking. ADM electromyographic (EMG) activity and contraction force were measured before (Pre), immediately after, and following 5 and 10 min post stimulation (post 1, post 2). The results showed that EMG activity decreased immediately after stimulation compared to prestimulation, it returned to the level of prestimulation at 5 min (post 1), and decreased again at 10 min (post 2). Furthermore, analysis of compound adjusted z-score indicated significant decrease of force and myoelectrical activity immediately, and 10 min post stimulation. The findings, which demonstrate that KHFAC surface stimulation of the ulnar nerve may decrease the motor activity of intrinsic hand muscle, can help to develop future methods of neuromodulation to treat hand spasticity. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  15. Revisiting the Single-Visit Protocol for Determining the Electromyographic Fatigue Threshold.

    Science.gov (United States)

    Khan, Fatin L; Lawal, Jordan M; Kapture, Drew O; Swingle, Joseph D; Malek, Moh H

    2017-12-01

    Khan, FL, Lawal, JM, Kapture, DO, Swingle, JD, and Malek, MH. Revisiting the single-visit protocol for determining the electromyographic fatigue threshold. J Strength Cond Res 31(12): 3503-3507, 2017-The electromyographic fatigue threshold (EMGFT) has been shown to demarcate between nonfatiguing and fatiguing exercise workloads. One potential limitation of incorporating the single EMGFT test in a clinical setting is the 2-minute stage increment inherit to the protocol. In most rehabilitation clinics, time with the client is limited, and any testing procedure needs to consider this factor. The purpose of this study, therefore, was to determine whether or not the estimation of the EMGFT is influenced by reducing the incremental stage to 1-minute intervals. We hypothesized that the 1-minute incremental protocol would provide similar estimates of the EMGFT as the traditional 2-minute incremental protocol. Nine college-aged men performed the single-leg knee-extensor ergometry at 1-minute (3 W) and 2-minute (6 W) stages in random order separated by 7 days. The exercise indices and the EMGFT were determined from the 2 protocols and analyzed using a paired samples t test. The EMG amplitude was assessed from the rectus femoris muscle. The results indicated significant differences between protocols for maximal power output (1 minute: 31.7 ± 2.2 W vs. 2 minutes: 38.0 ± 3.3 W, p = 0.016) and heart rate at end exercise (1 minute: 137 ± 5 b·min vs. 2 minutes: 148 ± 5 b·min, p = 0.024). There were, however, no significant mean differences for the EMGFT (1 minute: 19.8 ± 1.8 vs. 2 minutes: 20.3 ± 1.9 W, p = 0.63) and rating of perceived exertion (RPE) for the exercised leg (1 minute: 9 ± 0 vs. 2 minutes: 9 ± 1, p = 0.68). These results indicate that reducing the exercise protocol by 50% did not change the estimated EMGFT. The practical application of this finding resides in the potential use in sports or rehabilitative settings in which there is limited time with the

  16. An Electromyographic-driven Musculoskeletal Torque Model using Neuro-Fuzzy System Identification: A Case Study

    Science.gov (United States)

    Jafari, Zohreh; Edrisi, Mehdi; Marateb, Hamid Reza

    2014-01-01

    The purpose of this study was to estimate the torque from high-density surface electromyography signals of biceps brachii, brachioradialis, and the medial and lateral heads of triceps brachii muscles during moderate-to-high isometric elbow flexion-extension. The elbow torque was estimated in two following steps: First, surface electromyography (EMG) amplitudes were estimated using principal component analysis, and then a fuzzy model was proposed to illustrate the relationship between the EMG amplitudes and the measured torque signal. A neuro-fuzzy method, with which the optimum number of rules could be estimated, was used to identify the model with suitable complexity. Utilizing the proposed neuro-fuzzy model, the clinical interpretability was introduced; contrary to the previous linear and nonlinear black-box system identification models. It also reduced the estimation error compared with that of the most recent and accurate nonlinear dynamic model introduced in the literature. The optimum number of the rules for all trials was 4 ± 1, that might be related to motor control strategies and the % variance accounted for criterion was 96.40 ± 3.38 which in fact showed considerable improvement compared with the previous methods. The proposed method is thus a promising new tool for EMG-Torque modeling in clinical applications. PMID:25426427

  17. Electromyographic activity of preterm newborns in the kangaroo position: a cohort study.

    Science.gov (United States)

    Miranda, Rafael Moura; Cabral Filho, José Eulálio; Diniz, Kaísa Trovão; Souza Lima, Geisy Maria; Vasconcelos, Danilo de Almeida

    2014-10-28

    To compare the electromyographic activity of preterm newborns placed in the kangaroo position with the activity of newborns not placed in this position. A cohort study. A Kangaroo Unit sector and a Nursery sector in a secondary and tertiary care at a mother-child hospital in Recife, Brazil. Preterm infants of gestational age 27-34 weeks (n=38) and term infants (n=39). Surface electromyography was used to investigate muscle activity in the brachial biceps at rest. 3 groups were designed: (1) preterm newborns in the kangaroo position (PT-KAN), where the newborn remains in a vertical position, lying face down, with limbs flexed, dressed in light clothes, maintaining skin-to-skin contact with the adult's thorax. Her electromyographic activity was recorded at 0 h (immediately before starting this position), and then at 48 h after the beginning of the position (but newborns were kept in the kangaroo position for 8-12 h per day) and at term equivalent age (40±1 weeks); (2) preterm newborns not in the kangaroo position (PT-NKAN), in which measurements were made at 0 h and 48 h; and (3) term newborns (T), in which measurements were made at 24 h of chronological age. The Root Mean Square (RMS) values showed significant differences among groups (F(5,108)=56.69; ppreterm group in the kangaroo position, but not in the group not submitted in the kangaroo position. The RMS in the term equivalent aged group in the kangaroo position was also greater when compared with those in the term group. The kangaroo position increases electromyographic activity in the brachial biceps of preterm newborns and those who have reached the age equivalent to term. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. Automatic multi-modal intelligent seizure acquisition (MISA) system for detection of motor seizures from electromyographic data and motion data

    DEFF Research Database (Denmark)

    Conradsen, Isa; Beniczky, Sándor; Wolf, Peter

    2012-01-01

    The objective is to develop a non-invasive automatic method for detection of epileptic seizures with motor manifestations. Ten healthy subjects who simulated seizures and one patient participated in the study. Surface electromyography (sEMG) and motion sensor features were extracted as energy...

  19. Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

    Directory of Open Access Journals (Sweden)

    Tamara Grujic Supuk

    2014-05-01

    Full Text Available Surface electromyography (sEMG is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics, we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius. The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics.

  20. A Novel Electromyographic Approach to Estimate Fatigue Threshold in Maximum Incremental Strength Tests.

    Science.gov (United States)

    Aragón-Vela, Jerónimo; Barranco-Ruiz, Yaira; Casals-Vázquez, Cristina; Plaza-Díaz, Julio; Casuso, Rafael A; Fontana, Luis; Huertas, Jesús F Rodríguez

    2018-04-01

    Evaluation of muscular fatigue thresholds in athletes performing short-duration and explosive exercises is difficult because classic parameters do not suffer large variations. Therefore, the aim of this study was to develop a new method to estimate the fatigue threshold in single muscles. Our approach is based on electromyographic data recorded during a maximum incremental strength test until the one repetition maximum is reached. Ten men and 10 women performed a half-squat strength test consisting of five incremental intensities of one repetition maximum. Neither heart rate nor blood lactate concentrations showed significant differences at the various intensities tested. Surface electromyographic activities of vastus lateralis, vastus medialis, and rectus femoris were recorded, finding a break point corresponding to the fatigue threshold occurring in men at 70.74%, 71.48%, and 72.52% of one repetition maximum, respectively. In women, break-point values were 76.66% for vastus lateralis, 76.27% for vastus medialis, and 72.10% for rectus femoris. In conclusion, surface electromyography could be a useful, rapid, and noninvasive tool to determine the fatigue threshold of independent muscles during a maximal half-squat strength test.

  1. The impact of shoulder abduction loading on EMG-based intention detection of hand opening and closing after stroke.

    Science.gov (United States)

    Lan, Yiyun; Yao, Jun; Dewald, Julius P A

    2011-01-01

    Many stroke patients are subject to limited hand functions in the paretic arm due to a significant loss of Corticospinal Tract (CST) fibers. A possible solution for this problem is to classify surface Electromyography (EMG) signals generated by hand movements and uses that to implement Functional Electrical Stimulation (FES). However, EMG usually presents an abnormal muscle coactivation pattern shown as increased coupling between muscles within and/or across joints after stroke. The resulting Abnormal Muscle Synergies (AMS) could make the classification more difficult in individuals with stroke, especially when attempting to use the hand together with other joints in the paretic arm. Therefore, this study is aimed at identifying the impact of AMS following stroke on EMG pattern recognition between two hand movements. In an effort to achieve this goal, 7 chronic hemiparetic chronic stroke subjects were recruited and asked to perform hand opening and closing movements at their paretic arm while being either fully supported by a virtual table or loaded with 25% of subject's maximum shoulder abduction force. During the execution of motor tasks EMG signals from the wrist flexors and extensors were simultaneously acquired. Our results showed that increased synergy-induced activity at elbow flexors, induced by increasing shoulder abduction loading, deteriorated the performance of EMG pattern recognition for hand opening for those with a weak grasp strength and EMG activity. However, no such impact on hand closing has yet been observed possibly because finger/wrist flexion is facilitated by the shoulder abduction-induced flexion synergy.

  2. Assessment of the paraspinal muscles of subjects presenting an idiopathic scoliosis: an EMG pilot study

    Directory of Open Access Journals (Sweden)

    Larivière Christian

    2005-03-01

    Full Text Available Abstract Background It is known that the back muscles of scoliotic subjects present abnormalities in their fiber type composition. Some researchers have hypothesized that abnormal fiber composition can lead to paraspinal muscle dysfunction such as poor neuromuscular efficiency and muscle fatigue. EMG parameters were used to evaluate these impairments. The purpose of the present study was to examine the clinical potential of different EMG parameters such as amplitude (RMS and median frequency (MF of the power spectrum in order to assess the back muscles of patients presenting idiopathic scoliosis in terms of their neuromuscular efficiency and their muscular fatigue. Methods L5/S1 moments during isometric efforts in extension were measured in six subjects with idiopathic scoliosis and ten healthy controls. The subjects performed three 7 s ramp contractions ranging from 0 to 100% maximum voluntary contraction (MVC and one 30 s sustained contraction at 75% MVC. Surface EMG activity was recorded bilaterally from the paraspinal muscles at L5, L3, L1 and T10. The slope of the EMG RMS/force (neuromuscular efficiency and MF/force (muscle composition relationships were computed during the ramp contractions while the slope of the EMG RMS/time and MF/time relationships (muscle fatigue were computed during the sustained contraction. Comparisons were performed between the two groups and between the left and right sides for the EMG parameters. Results No significant group or side differences between the slopes of the different measures used were found at the level of the apex (around T10 of the major curve of the spine. However, a significant side difference was seen at a lower level (L3, p = 0.01 for the MF/time parameter. Conclusion The EMG parameters used in this study could not discriminate between the back muscles of scoliotic subjects and those of control subject regarding fiber type composition, neuromuscular efficiency and muscle fatigue at the level

  3. Efeitos da eletroestimulação do músculo vasto medial oblíquo em portadores de síndrome da dor patelofemoral: uma análise eletromiográfica Effects of electrical stimulation of vastus medialis obliquus muscle in patients with patellofemoral pain syndrome: an electromyographic analysis

    Directory of Open Access Journals (Sweden)

    Fabiana R. Garcia

    2010-12-01

    Full Text Available CONTEXTUALIZAÇÃO: O uso da eletromiografia de superfície (EMG-S tem sido considerado como instrumento de avaliação quantitativa na síndrome da dor patelofemoral (SDPF. Tratamentos conservadores objetivam melhorar o alinhamento patelar, e a estimulação elétrica do músculo vasto medial oblíquo (VMO tem sido considerada por ser seletiva e não causar irritação articular. OBJETIVO: Verificar o efeito de um programa de fortalecimento muscular com estimulação elétrica do VMO na SDPF por meio da capacidade de avaliação da EMG-S. MÉTODOS: Participaram deste estudo 10 mulheres jovens (idade: 23,1±4,9 anos; massa corporal: 66,8±14,0 kg; estatura: 1,63±6,9 cm; IMC: 25,1±5,6 kg/m² com SDPF unilateral, as quais realizaram o teste funcional de subir degrau para captação da atividade eletromiográfica dos músculos VMO e vasto lateral (VL, antes e após um programa de estimulação elétrica do VMO. A eletroestimulação foi realizada três vezes por semana, durante seis semanas. Foram consideradas, para análise entre VMO e VL, as variáveis razão do tempo do início até o pico de ativação, razão da integral do sinal (teste t para amostras dependentes e diferença de início de ativação (teste de Wilcoxon, com n��vel de significância de pBACKGROUND: The use of surface electromyography (SEMG has been considered a tool for quantitative assessment of patellofemoral pain syndrome (PFPS. Conservative treatments aim to improve patellar alignment, and electrical stimulation of the vastus medialis obliquus (VMO muscle has been considered effective because it is selective and does not cause joint irritation. OBJECTIVE: This study aims to investigate the efficiency of a muscle strengthening program with electrical stimulation of the VMO muscle in PFPS by SEMG. METHODS: A group of ten young women (age: 23.1±4.9 years; body mass: 66.8±14.0 kg; height: 1.63±6.9 cm; BMI: 25.1±5.6 kg/m² with unilateral PFPS participated in the

  4. Filter banks and the "Intensity Analysis" of EMG

    OpenAIRE

    Borg, Frank

    2010-01-01

    Vinzenz von Tscharner (2000) has presented an interesting mathematical method for analyzing EMG-data called "intensity analysis" (EMG = electromyography). Basically the method is a sort of bandpassing of the signal. The central idea of the method is to describe the "power" (or "intensity") of a non-stationary EMG signal as a function both of time and of frequency. The connection with wavelet theory is that the filter is constructed by rescaling a given mother wavelet using a special array of ...

  5. An EMG-Controlled SMA Device for the Rehabilitation of the Ankle Joint in Post-Acute Stroke

    Science.gov (United States)

    Pittaccio, S.; Viscuso, S.

    2011-07-01

    The capacity of flexing one's ankle is an indispensible segment of gait re-learning, as imbalance, wrong compensatory use of other joints and risk of falling may depend on the so-called drop-foot. The rehabilitation of ankle dorsiflexion may be achieved through active exercising of the relevant musculature (especially tibialis anterior, TA). This can be troublesome for patients affected by weakness and flaccid paresis. Thus, as needs evolve during patient's improvements, a therapeutic device should be able to guide and sustain gradual recovery by providing commensurate aid. This includes exploiting even initial attempts at voluntary motion and turns those into effective workout. An active orthosis powered by two rotary actuators containing NiTi wire was designed to obtain ankle dorsiflexion. A computer routine that analyzes the electromyographic (sEMG) signal from TA muscle is used to control the orthosis and trigger its activation. The software also provides instructions and feed-back for the patient. Tests on the orthosis proved that it can produce strokes up to 36° against resisting torques exceeding 180 Ncm. Three healthy subjects were able to control the orthosis by modulating their TA sEMG activity. The movement produced in the preliminary tests is interesting for lower limb rehabilitation, and will be further improved by optimizing body-orthosis interface. It is hoped that this device will enhance early rehabilitation and recovery of ankle mobility in stroke patients.

  6. Feasibility of using combined EMG and kinematic signals for prosthesis control: A simulation study using a virtual reality environment.

    Science.gov (United States)

    Blana, Dimitra; Kyriacou, Theocharis; Lambrecht, Joris M; Chadwick, Edward K

    2016-08-01

    Transhumeral amputation has a significant effect on a person's independence and quality of life. Myoelectric prostheses have the potential to restore upper limb function, however their use is currently limited due to lack of intuitive and natural control of multiple degrees of freedom. The goal of this study was to evaluate a novel transhumeral prosthesis controller that uses a combination of kinematic and electromyographic (EMG) signals recorded from the person's proximal humerus. Specifically, we trained a time-delayed artificial neural network to predict elbow flexion/extension and forearm pronation/supination from six proximal EMG signals, and humeral angular velocity and linear acceleration. We evaluated this scheme with ten able-bodied subjects offline, as well as in a target-reaching task presented in an immersive virtual reality environment. The offline training had a target of 4° for flexion/extension and 8° for pronation/supination, which it easily exceeded (2.7° and 5.5° respectively). During online testing, all subjects completed the target-reaching task with path efficiency of 78% and minimal overshoot (1.5%). Thus, combining kinematic and muscle activity signals from the proximal humerus can provide adequate prosthesis control, and testing in a virtual reality environment can provide meaningful data on controller performance. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. An EMG-to-Force Processing approach for estimating in vivo hip muscle forces in normal human walking.

    Science.gov (United States)

    Bogey, Ross A; Barnes, Lee A

    2016-10-12

    The force of a single muscle is not directly measurable without invasive methods. Yet invasive techniques are not appropriate for clinical use, thus a non-invasive technique that combined the electromyographic (EMG) signal and a neuromuscular model was developed to determine in vivo active muscle forces at the hip. The EMG-to-force processing (EFP) model included active and passive moment components, and the net EFP moment was compared with the hip moment obtained with standard inverse dynamics techniques ("gold standard"). The two methods were compared at percent gait cycle intervals, and the correlation coefficient between methods was excellent (r2=91). The closeness of fit confirms that the approach is a reasonable approximation of net moment and, possibly, individual muscle forces. The greatest estimated hip force was produced by a hip abductor. A novel finding was that the hip adductors did not behave a single synergistic group. The Adductor Magnus synergistically assisted other hip extensors, and produced forces that were out-of-phase with the other hip adductor forces. Rectus Femoris was only active during hip flexion (not knee extension).

  8. Verification of a standardized method for inserting intramuscular EMG electrodes into uniquely oriented segments of gluteus minimus and gluteus medius.

    Science.gov (United States)

    Semciw, A I; Green, R A; Pizzari, T; Briggs, C

    2013-03-01

    Guidelines for assessing the function of gluteus minimus and gluteus medius with electromyography (EMG) traditionally offer one electrode placement site per muscle. However, anatomical studies suggest that there are two uniquely oriented segments within gluteus minimus (anterior and posterior), and three within gluteus medius (anterior, middle, and posterior) with potential for independent function. Assessment of these muscles with one electrode may therefore provide only a limited account of their role. Thus, the aim of this cadaveric study was to verify guidelines for placing intramuscular electrodes into two uniquely oriented segments of gluteus minimus, and three segments of gluteus medius. The guidelines were developed with reference to anatomical reports, cadaveric observation and real-time ultrasound imaging in vivo. Five cadaveric gluteal regions were marked for intramuscular electrode insertions based on these guidelines. Intramuscular electrodes were inserted into the marked regions of gluteus minimus (2×) and gluteus medius (3×) with the aid of a 15 cm biopsy needle. Systematic dissection revealed that electrodes were successfully inserted into uniquely oriented segments of gluteus minimus and medius. The orientation of fascicles surrounding each electrode was also consistent with segmental descriptions in past anatomical research. The findings of this research suggest that the guidelines described may be used to assess the functional role of segments within gluteus minimus and medius in health and dysfunction using EMG. Finally, electromyographers intent on investigating the role of posterior gluteus minimus must be cautious of the superior gluteal neurovascular bundle. Copyright © 2012 Wiley Periodicals, Inc.

  9. Development of three-dimensional shoulder kinematic and electromyographic exposure variation analysis methodology in violin musicians.

    Science.gov (United States)

    Reynolds, Jonathan F; Leduc, Robert E; Kahnert, Emily K; Ludewig, Paula M

    2014-01-01

    A total of 11 male and 19 female violinists performed 30-second random-ordered slow and fast musical repertoire while right shoulder three-dimensional kinematic, and upper trapezius and serratus anterior surface electromyography (EMG) data were summarised using exposure variation analysis (EVA), a bivariate distribution of work time spent at categories of signal amplitude, and duration spent at a fixed category of amplitude. Sixty-two per cent of intraclass correlation coefficients [1,1] for all kinematic and EMG variables exceeded 0.75, and 40% of standard error of the measurement results were below 5%, confirming EVA reliability. When fast repertoire was played, increases in odds ratios in short duration cells were seen in 23 of 24 possible instances, and decreases in longer duration cells were seen in 17 instances in all EVA arrays using multinomial logistic regression with random effects, confirming a shift towards shorter duration. A reliable technique to assess right shoulder kinematic and EMG exposure in violinists was identified. A reliable method of measuring right shoulder motion and muscle activity exposure variation in violinists was developed which can be used to assess ergonomic risk in other occupations. Recently developed statistical methods enabled differentiation between fast and slow musical performance of standardised musical repertoire.

  10. Electromyographic analysis of lower limb muscles during the golf swing performed with three different clubs.

    Science.gov (United States)

    Marta, Sérgio; Silva, Luís; Vaz, João Rocha; Castro, Maria António; Reinaldo, Gustavo; Pezarat-Correia, Pedro

    2016-01-01

    The aim of this study was to describe and compare the EMG patterns of select lower limb muscles throughout the golf swing, performed with three different clubs, in non-elite middle-aged players. Fourteen golfers performed eight swings each using, in random order, a pitching wedge, 7-iron and 4-iron. Surface electromyography (EMG) was recorded bilaterally from lower limb muscles: tibialis anterior, peroneus longus, gastrocnemius medialis, gastrocnemius lateralis, biceps femoris, semitendinosus, gluteus maximus, vastus medialis, rectus femoris and vastus lateralis. Three-dimensional high-speed video analysis was used to determine the golf swing phases. Results showed that, in average handicap golfers, the highest muscle activation levels occurred during the Forward Swing Phase, with the right semitendinosus and the right biceps femoris muscles producing the highest mean activation levels relative to maximal electromyography (70-76% and 68-73% EMG(MAX), respectively). Significant differences between the pitching wedge and the 4-iron club were found in the activation level of the left semitendinosus, right tibialis anterior, right peroneus longus, right vastus medialis, right rectus femuris and right gastrocnemius muscles. The lower limb muscles showed, in most cases and phases, higher mean values of activation on electromyography when golfers performed shots with a 4-iron club.

  11. Muscle Performance Investigated With a Novel Smart Compression Garment Based on Pressure Sensor Force Myography and Its Validation Against EMG

    Directory of Open Access Journals (Sweden)

    Aaron Belbasis

    2018-04-01

    Full Text Available Muscle activity and fatigue performance parameters were obtained and compared between both a smart compression garment and the gold-standard, a surface electromyography (EMG system during high-speed cycling in seven participants. The smart compression garment, based on force myography (FMG, comprised of integrated pressure sensors that were sandwiched between skin and garment, located on five thigh muscles. The muscle activity was assessed by means of crank cycle diagrams (polar plots that displayed the muscle activity relative to the crank cycle. The fatigue was assessed by means of the median frequency of the power spectrum of the EMG signal; the fractal dimension (FD of the EMG signal; and the FD of the pressure signal. The smart compression garment returned performance parameters (muscle activity and fatigue comparable to the surface EMG. The major differences were that the EMG measured the electrical activity, whereas the pressure sensor measured the mechanical activity. As such, there was a phase shift between electrical and mechanical signals, with the electrical signals preceding the mechanical counterparts in most cases. This is specifically pronounced in high-speed cycling. The fatigue trend over the duration of the cycling exercise was clearly reflected in the fatigue parameters (FDs and median frequency obtained from pressure and EMG signals. The fatigue parameter of the pressure signal (FD showed a higher time dependency (R2 = 0.84 compared to the EMG signal. This reflects that the pressure signal puts more emphasis on the fatigue as a function of time rather than on the origin of fatigue (e.g., peripheral or central fatigue. In light of the high-speed activity results, caution should be exerted when using data obtained from EMG for biomechanical models. In contrast to EMG data, activity data obtained from FMG are considered more appropriate and accurate as an input for biomechanical modeling as they truly reflect the mechanical

  12. Electromyographic and biomechanic analysis of anterior cruciate ligament deficiency and functional knee bracing.

    Science.gov (United States)

    Ramsey, Dan K; Wretenberg, Per F; Lamontagne, Mario; Németh, Gunnar

    2003-01-01

    Examine the neuromuscular response to functional knee bracing relative to anterior tibial translations in vivo. During randomised brace conditions, electromyographic data with simultaneous skeletal tibiofemoral kinematics were recorded from four anterior cruciate ligament deficient subjects to investigate the effect of the DonJoy Legend functional brace during activity. Knee braces do not increase knee stability but may influence afferent inputs from proprioception and therefore one might expect changes in muscle firing patterns, amplitude and timing. Hoffman bone pins affixed with markers were implanted into the tibia and femur for kinematic measurement. The EMG data from the rectus femoris, semitendinosus, biceps femoris, and lateral head of the gastrocnemius were integrated for each subject in three separate time periods: 250 ms preceding footstrike and two consecutive 125 ms time intervals following footstrike. With brace, semitendinosus activity significantly decreased 17% prior to footstrike whereas bicep femoris significantly decreased 44% during A2, (P<0.05). Rectus femoris activity significantly increased 21% in A2 (P<0.05). No consistent reductions in anterior translations were evident. Our preliminary findings, based on a limited number of subjects, indicate joint stability may result from proprioceptive feedback rather than the mechanical stabilising effect of the brace. Despite a significant increase in rectus femoris activity upon landing, only one subject demonstrated an increase in anterior tibial drawer. Studies have shown functional braces do not mechanically stabilise the anterior cruciate ligament deficient knee. Perhaps bracing alters proprioceptive feedback. It has been shown that bracing the anterior cruciate ligament deficient knee may affect hamstring and quadriceps activity. Our findings stresses the importance of functional knee bracing combined with proprioceptive and muscular coordination training in order to increase joint stability.

  13. Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

    Science.gov (United States)

    Saito, Akira; Akima, Hiroshi

    2013-12-01

    It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Muscle fatigue evaluation of astronaut upper limb based on sEMG and subjective assessment

    Science.gov (United States)

    Zu, Xiaoqi; Zhou, Qianxiang; Li, Yun

    2012-07-01

    All movements are driven by muscle contraction, and it is easy to cause muscle fatigue. Evaluation of muscle fatigue is a hot topic in the area of astronaut life support training and rehabilitation. If muscle gets into fatigue condition, it may reduce work efficiency and has an impact on psychological performance. Therefore it is necessary to develop an accurate and usable method on muscle fatigue evaluation of astronaut upper limb. In this study, we developed a method based on surface electromyography (sEMG) and subjective assessment (Borg scale) to evaluate local muscle fatigue. Fifteen healthy young male subjects participated in the experiment. They performed isometric muscle contractions of the upper limb. sEMG of the biceps brachii were recorded during the entire process of isotonic muscle contraction and Borg scales of muscle fatigue were collected in certain times. sEMG were divided into several parts, and then mean energy of each parts were calculated by the one-twelfth band octave method. Equations were derived based on the relationship between the mean energy of sEMG and Borg scale. The results showed that cubic curve could describe the degree of local muscle fatigue, and could be used to evaluate and monitor local muscle fatigue during the entire process.

  15. Detection of Simulated Vocal Dysfunctions Using Complex sEMG Patterns.

    Science.gov (United States)

    Smith, Nicholas R; Rivera, Luis A; Dietrich, Maria; Shyu, Chi-Ren; Page, Matthew P; DeSouza, Guilherme N

    2016-05-01

    Symptoms of voice disorder may range from slight hoarseness to complete loss of voice; from modest vocal effort to uncomfortable neck pain. But even minor symptoms may still impact personal and especially professional lives. While early detection and diagnosis can ameliorate that effect, to date, we are still largely missing reliable and valid data to help us better screen for voice disorders. In our previous study, we started to address this gap in research by introducing an ambulatory voice monitoring system using surface electromyography (sEMG) and a robust algorithm (HiGUSSS) for pattern recognition of vocal gestures. Here, we expand on that work by further analyzing a larger set of simulated vocal dysfunctions. Our goal is to demonstrate that such a system has the potential to recognize and detect real vocal dysfunctions from multiple individuals with high accuracy under both intra and intersubject conditions. The proposed system relies on four sEMG channels to simultaneously process various patterns of sEMG activation in the search for maladaptive laryngeal activity that may lead to voice disorders. In the results presented here, our pattern recognition algorithm detected from two to ten different classes of sEMG patterns of muscle activation with an accuracy as high as 99%, depending on the subject and the testing conditions.

  16. The averaged EMGs recorded from the arm muscles during bimanual rowing movements

    Directory of Open Access Journals (Sweden)

    Tomasz eTomiak

    2015-11-01

    Full Text Available The main purpose was to analyze quantitatively the the average surface EMGs of the muscles that function around the elbow and shoulder joints of both arms in similar bimanual ‘rowing’ movements, which were produced under identical elastic loads applied to the levers (‘oars’. The muscles of PM group (‘pulling’ muscles: elbow flexors, shoulder extensors generated noticeable velocity-dependent dynamic EMG components during the pulling and returning phases of movement and supported a steady-state activity during the hold phase. The muscles of RM group (‘returning’ muscles: elbow extensors, shoulder flexors co-contracted with PM group during the movement phases and decreased activity during the hold phase. The dynamic components of the EMGs strongly depended on the velocity factor in both muscle groups, whereas the side and load factors and combinations of various factors acted only in PM group muscles. Various subjects demonstrated diverse patterns of activity redistribution among muscles. We assume that central commands to the same muscles in two arms may be essentially different during execution of similar movement programs. Extent of the diversity in the EMG patterns of such muscles may reflect the subject’s skilling in motor performance; on the other hand, the diversity can reflect redistribution of activity between synergic muscles, thus providing a mechanism directed against development of the muscle fatigue.

  17. Lumbar paraspinal electromyographic activity during trunk extension exercises on two types of exercise machines.

    Science.gov (United States)

    Walsworth, M

    2004-06-01

    The objective of this study was to evaluate and compare lumbar paraspinal muscle activity during trunk extension exercises on two lumbar extension machines with different types of pelvic stabilization mechanisms. Thirteen healthy male (n = 9) and female (n = 4) volunteers aged 21-24 (22.6 +/- 1.4) were recruited in a university setting. Surface electromyographic activity was recorded bilaterally from the L3-4 paraspinal region during trunk extension exercises performed on two different exercise machines. One machine, the MedX, has a complex pelvic stabilization mechanism. The other machine, the Cybex, has a relatively simple pelvic stabilization mechanism. There was no significant difference between lumbar paraspinal electromyographic activity during trunk extension on the MedX compared to the Cybex dynamic variable resistance trunk extension machine. These results suggest that a complex pelvic stabilization mechanism does not significantly enhance the level of activation of the lumbar paraspinal muscles during lumbar extension exercises. Thus, a less expensive trunk extension machine with a less sophisticated pelvic stabilization mechanism, such as the Cybex, can be used to train the lumbar paraspinal muscles. This is important to rehabilitation clinicians because these machines are often more readily available and easier for patients to use. Further research is warranted to determine the applicability of these findings to a patient population.

  18. EMG Analysis and Sagittal Plane Kinematics of the Two-Handed and Single-Handed Kettlebell Swing: A Descriptive Study.

    Science.gov (United States)

    Van Gelder, Leonard H; Hoogenboom, Barbara J; Alonzo, Bryan; Briggs, Dayna; Hatzel, Brian

    2015-11-01

    Kettlebell (KB) swing exercises have been proposed as a possible method to improve hip and spinal motor control as well as improve power, strength, and endurance. To describe electromyographic (EMG) and sagittal plane kinematics during two KB exercises: the two-handed KB swing (THKS) and the single-handed KB swing (SHKS). In addition, the authors sought to investigate whether or not hip flexor length related to the muscular activity or the kinematics of the exercise. Twenty-three healthy college age subjects participated in this study. Demographic information and passive hip flexor length were recorded for each subject. A maximum voluntary isometric contraction (MVIC) of bilateral gluteus maximus (GMAX), gluteus medius (GMED), and biceps femoris (BF) muscles was recorded. EMG activity and sagittal plane video was recorded during both the THKS and SHKS in a randomized order. Normalized muscular activation of the three studied muscles was calculated from EMG data. During both SHKS and THKS, the average percent of peak MVIC for GMAX was 75.02% ± 55.38, GMED 55.47% ± 26.33, and BF 78.95% ± 53.29. Comparisons of the mean time to peak activation (TTP) for each muscle showed that the biceps femoris was the first muscle to activate during the swings. Statistically significant (p < .05), moderately positive correlations (r = .483 and .417) were found between passive hip flexor length and % MVIC for the GMax during the SHKS and THKS, respectively. The THKS and SHKS provide sufficient muscular recruitment for strengthening of all of the muscles explored. This is the first study to show significant correlations between passive hip flexor length and muscular activation of hip extensors, particularly the GMax. Finally, the BF consistently reached peak activity before the GMax and GMed during the SHKS. Level 3.

  19. Changes in EMG Activities of Upper Arm Muscles and in Shoulder Joint Angles in Post-stroke Patients

    Directory of Open Access Journals (Sweden)

    Rositsa Raikova

    2016-09-01

    Full Text Available The aim of the paper is to compare the electromyographic signals (EMGs and the joint angles of the affected upper limb muscles of stroke survivors to those of their non-affected limb as well as to those of the dominant and the non-dominant limbs of healthy volunteers. Twenty five volunteers, ten post-stroke survivors and fifteen healthy subjects as control group, participated in the experiments. EMGs of muscles of the upper limbs and two angles in the shoulder joint were registered and processed during three static and two dynamic tasks. The results showed a big variability of all investigated parameters (mean and median frequencies, ranges of motions, maximal normalized EMGs both for the patients and for the healthy subjects, for right and for left hand. This makes difficult a deduction of definitive conclusions about the changes in motor control of the upper limbs due to stroke. Moreover, natural differences in motor control exist for dominant and non-dominant limb. On the whole, the power-frequency analysis and the relevant statistical analysis indicated that the muscles of the affected limb had lower median frequencies than those of the healthy limb. Examination of full elbow flexions in the sagittal plane showed that the range of the motion in the shoulder joint of both limbs of the patients increased when compared to the healthy subjects and that this increase was larger for the affected limb. The post-stroke survivors used more of their muscle power although no increased co-contraction was observed.

  20. Young, Healthy Subjects Can Reduce the Activity of Calf Muscles When Provided with EMG Biofeedback in Upright Stance.

    Science.gov (United States)

    Vieira, Taian M; Baudry, Stéphane; Botter, Alberto

    2016-01-01

    Recent evidence suggests the minimization of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimizing the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG) recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimize the level of muscle activation during standing without increasing the excursion of the center of pressure (CoP). CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from 10 healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects' responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at assisting subjects in more efficiently controlling leg muscle activity during standing.

  1. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  2. EMGTools, an adaptive and versatile tool for detailed EMG analysis

    DEFF Research Database (Denmark)

    Nikolic, M; Krarup, C

    2010-01-01

    We have developed an EMG decomposition system called EMGTools that can extract the constituent MUAPs and firing patterns for quantitative analysis from the EMG signal recorded at slight effort for clinical evaluation. The aim was to implement a robust system able to handle the challenges...

  3. EMG MEDIAN POWER FREQUENCY IN AN EXHAUSTING EXERCISE

    NARCIS (Netherlands)

    AMENT, W; BONGA, GJJ; HOF, AL; VERKERKE, GJ

    1993-01-01

    EMG median power frequency of the calf muscles was investigated during an exhausting treadmill exercise. This exercise was an uphill run, the average endurance time was 1.5 min. Median power frequency of the calf muscles declined by more than 10% during this exercise. In addition EMG median power

  4. Masticatory function in temporomandibular dysfunction patients: electromyographic evaluation

    OpenAIRE

    Berretin-Felix,Giédre; Genaro,Katia Flores; Trindade,Inge Elly Kiemle; Trindade Júnior,Alceu Sergio

    2005-01-01

    Temporomandibular dysfunction (TMD) is a complex disturbance that involves the masticatory muscles and/or temporomandibular joint, causing damage to the masticatory function. This study evaluated the electromyographic activity of the masseter muscle during habitual mastication of bread, apple, banana, cashew nut and paraffin film (Parafilm M) in 25 adult subjects, of both gender, with TMD. The results were compared to those of a control group, composed of 15 adult subjects, of both sexes, fre...

  5. EMG-based facial gesture recognition through versatile elliptic basis function neural network.

    Science.gov (United States)

    Hamedi, Mahyar; Salleh, Sh-Hussain; Astaraki, Mehdi; Noor, Alias Mohd

    2013-07-17

    Recently, the recognition of different facial gestures using facial neuromuscular activities has been proposed for human machine interfacing applications. Facial electromyograms (EMGs) analysis is a complicated field in biomedical signal processing where accuracy and low computational cost are significant concerns. In this paper, a very fast versatile elliptic basis function neural network (VEBFNN) was proposed to classify different facial gestures. The effectiveness of different facial EMG time-domain features was also explored to introduce the most discriminating. In this study, EMGs of ten facial gestures were recorded from ten subjects using three pairs of surface electrodes in a bi-polar configuration. The signals were filtered and segmented into distinct portions prior to feature extraction. Ten different time-domain features, namely, Integrated EMG, Mean Absolute Value, Mean Absolute Value Slope, Maximum Peak Value, Root Mean Square, Simple Square Integral, Variance, Mean Value, Wave Length, and Sign Slope Changes were extracted from the EMGs. The statistical relationships between these features were investigated by Mutual Information measure. Then, the feature combinations including two to ten single features were formed based on the feature rankings appointed by Minimum-Redundancy-Maximum-Relevance (MRMR) and Recognition Accuracy (RA) criteria. In the last step, VEBFNN was employed to classify the facial gestures. The effectiveness of single features as well as the feature sets on the system performance was examined by considering the two major metrics, recognition accuracy and training time. Finally, the proposed classifier was assessed and compared with conventional methods support vector machines and multilayer perceptron neural network. The average classification results showed that the best performance for recognizing facial gestures among all single/multi-features was achieved by Maximum Peak Value with 87.1% accuracy. Moreover, the results proved a

  6. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity

    Directory of Open Access Journals (Sweden)

    Karin Lienhard

    2015-01-01

    Full Text Available The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG spectrum recorded during whole-body vibration (WBV exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p < 0.05, and was significantly correlated to the sEMG signal without the spikes of the respective muscle (r range: 0.54 - 0.92, p < 0.05. This finding indicates that reflex activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity.

  7. A two-dimensional matrix image based feature extraction method for classification of sEMG: A comparative analysis based on SVM, KNN and RBF-NN.

    Science.gov (United States)

    Wen, Tingxi; Zhang, Zhongnan; Qiu, Ming; Zeng, Ming; Luo, Weizhen

    2017-01-01

    The computer mouse is an important human-computer interaction device. But patients with physical finger disability are unable to operate this device. Surface EMG (sEMG) can be monitored by electrodes on the skin surface and is a reflection of the neuromuscular activities. Therefore, we can control limbs auxiliary equipment by utilizing sEMG classification in order to help the physically disabled patients to operate the mouse. To develop a new a method to extract sEMG generated by finger motion and apply novel features to classify sEMG. A window-based data acquisition method was presented to extract signal samples from sEMG electordes. Afterwards, a two-dimensional matrix image based feature extraction method, which differs from the classical methods based on time domain or frequency domain, was employed to transform signal samples to feature maps used for classification. In the experiments, sEMG data samples produced by the index and middle fingers at the click of a mouse button were separately acquired. Then, characteristics of the samples were analyzed to generate a feature map for each sample. Finally, the machine learning classification algorithms (SVM, KNN, RBF-NN) were employed to classify these feature maps on a GPU. The study demonstrated that all classifiers can identify and classify sEMG samples effectively. In particular, the accuracy of the SVM classifier reached up to 100%. The signal separation method is a convenient, efficient and quick method, which can effectively extract the sEMG samples produced by fingers. In addition, unlike the classical methods, the new method enables to extract features by enlarging sample signals' energy appropriately. The classical machine learning classifiers all performed well by using these features.

  8. Association of the Bedside Shivering Assessment Scale and derived EMG power during therapeutic hypothermia in survivors of cardiac arrest.

    Science.gov (United States)

    May, Teresa; Seder, David B; Fraser, Gilles L; Tu, Chunhao; McCrum, Barbara; Lucas, Lee; Riker, Richard R

    2011-08-01

    Shivering during therapeutic hypothermia (TH) after cardiac arrest (CA) is common, but the optimal means of detection and appropriate threshold for treatment are not established. In an effort to develop a quantitative, continuous tool to measure shivering, we hypothesized that continuous derived electromyography (dEMG) power detected by the Aspect A2000 or VISTA monitor would correlate with the intermittent Bedside Shivering Assessment Scale (BSAS) performed by nurses. Among 38 patients treated with TH after CA, 853 hourly BSAS measurements were compared to dEMG power measured every minute by a frontal surface electrode. Patients received intermittent vecuronium by protocol to treat clinically recognized shivering (BSAS>0). Mean dEMG power in decibels (dB) was determined for the hour preceding each BSAS measurement. dEMG and BSAS were compared using ANOVA. The median dEMG power for a BSAS score of 0 (no shivering) was 27 dB (IQR 26-31 dB), BSAS 1 was 30.5 dB (IQR 28-35 dB), BSAS 2 was 34 dB (IQR 30-38 dB), and BSAS 3 was 34.5 dB (IQR 32-44.25). The dEMG for BSAS≥1 (shivering) was statistically different from BSAS 0 (pShivering Assessment Scale. Given its continuous trending of dEMG power, the A2000 or VISTA may be a useful research and clinical tool for objectively monitoring shivering. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Recidivemeting LEMA en EMG 2009 : Achtergrondkenmerken en strafrechtelijke recidive van de eerste LEMA- en EMG-deelnemers - tussentijdse rapportage

    NARCIS (Netherlands)

    Blom, M.

    2013-01-01

    In oktober 2008 zijn in Nederland de Lichte Educatieve Maatregel Alcohol en Verkeer (LEMA) en de Educatieve Maatregel Gedrag en Verkeer (EMG) ingevoerd. De volgende onderzoeksvragen staan centraal: Wat zijn de achtergrondkenmerken van LEMA- en EMG-deelnemers uit 2009?Wat is het recidivebeeld van

  10. Electromyographic activity of the anterolateral abdominal wall muscles during the vesical filling and evacuation

    Directory of Open Access Journals (Sweden)

    Ahmed Shafik

    2007-06-01

    Full Text Available

    BACKGROUND: The role of the anterolateral abdominal wall muscles (AAWMs during the vesical filling and evacuation has not been sufficiently addressed in the literature. We have investigated the hypothesis that the AAWMs exhibit the increased electromyographic (EMG activity on the vesical distension and contraction which presumably assists vesical evacuation.

    METHODS: The effects of the vesical balloon distension on the vesical pressure (VP, vesical neck (VNP pressures and the AAWMs' EMG activity were studied in 28 healthy volunteers aged 40.7 ± 9.7 years (18 men, 10 women. These effects were tested after the individual anesthetization of the bladder and AAWMs and after saline infiltration.

    RESULTS: The VP and the VNP showed a gradual increase upon the incremental vesical balloon distension which started at a distending volume of 120–140 ml. At a mean volume of 364.6 ± 23.8 ml, the VP increased to a mean of 36.6 ± 3.2 cmH2O, the VNP decreased to 18.4 ± 2.4 cmH2O, and the AAWMs EMG registered a significant increase. This effect disappeared in the individual bladder and in the AAWMs' anesthetization. However, it did not disappear in the saline administration.

    CONCLUSIONS: The AAWMs appear to contract simultaneously with vesical contraction. This action presumably increases the IAP and it

  11. Trunk and Shoulder Kinematic and Kinetic and Electromyographic Adaptations to Slope Increase during Motorized Treadmill Propulsion among Manual Wheelchair Users with a Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Dany Gagnon

    2015-01-01

    Full Text Available The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°. Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG of the pectoralis major (clavicular and sternal portions and deltoid (anterior and posterior fibers was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments.

  12. Relationship Between Electromyographic Signal Amplitude and Thickness Change of the Trunk Muscles in Patients With and Without Low Back Pain.

    Science.gov (United States)

    Djordjevic, Olivera; Konstantinovic, Ljubica; Miljkovic, Nadica; Bijelic, Goran

    2015-10-01

    To compare the relative thickness change of the transversal abdominal (TrA) and lumbar multifidus (LM) muscles during activation in individuals with and without low back pain (LBP), and to establish a relationship between surface electromyography (sEMG) signal amplitude and the relative thickness change of the corresponding muscle during clinically relevant activity, with preferential activation of TrA/LM. Thirty-seven pain-free participants and 36 LBP patients were assessed by ultrasound for thickness changes of TrA and LM and by sEMG for changes of electrical activity of the same muscles. sEMG is done with wireless LUMBIA system. The position of the sEMG sensors and activation maneuvers were chosen carefully. Significant group effect was found for relative thickness change of TrA (F1,142=60.69, Ppain-free patients (r=0.43-0.47, Ppain-free participants for both sides (r=0.36 to 0.38 Passessment. Correlation results suggest that the relative change of the muscle thickness could be used as the indicator of the muscle activity. Insight into the activity of TrA/LM in pain-free individuals and LBP patients during and after painful episodes may clarify the role of functional abnormalities of these muscles in LBP.

  13. Electromyographic analysis of the masseter and buccinator muscles with the pro-fono facial exerciser use in bruxers.

    Science.gov (United States)

    Jardini, Renata S R; Ruiz, Lydia S R; Moysés, Maria A A

    2006-01-01

    The aim of this study was to evaluate the efficiency of the Pró-Fono Facial Exerciser (Pró-Fono Productos Especializados para Fonoaudiologia Ltda., Barueri/SP, Brazil) to decrease bruxism, as well as the correlation between the masseter and the buccinator muscles using electromyography (EMG). In this study, 39 individuals ranging from 23 to 48 years of age were selected from a dental school and then underwent surface EMG at three different periods of time: 0, 10, and 70 days. They were divided into a normal control group, a bruxer control group (without device), and an experimental bruxer group who used the device. The bruxer group showed a greater masseter EMG amplitude when compared to the normal group, while the experimental group had deceased activity with a reduction in symptoms. The buccinator EMG spectral analysis of the experimental bruxist group showed asynchronous contractions of the masseter muscle (during jaw opening) after using the Pró-Fono Facial Exerciser. The normal group also showed asynchronous contractions. Upon correlation of the data between these muscles, the inference is that there is a reduction in bruxism when activating the buccinator muscle.

  14. EMG evaluation of hip adduction exercises for soccer players: implications for exercise selection in prevention and treatment of groin injuries.

    Science.gov (United States)

    Serner, Andreas; Jakobsen, Markus Due; Andersen, Lars Louis; Hölmich, Per; Sundstrup, Emil; Thorborg, Kristian

    2014-07-01

    Exercise programmes are used in the prevention and treatment of adductor-related groin injuries in soccer; however, there is a lack of knowledge concerning the intensity of frequently used exercises. Primarily to investigate muscle activity of adductor longus during six traditional and two new hip adduction exercises. Additionally, to analyse muscle activation of gluteals and abdominals. 40 healthy male elite soccer players, training >5 h a week, participated in the study. Muscle activity using surface electromyography (sEMG) was measured bilaterally for the adductor longus during eight hip adduction strengthening exercises and peak EMG was normalised (nEMG) using an isometric maximal voluntary contraction (MVC) as reference. Furthermore, muscle activation of the gluteus medius, rectus abdominis and the external abdominal obliques was analysed during the exercises. There were large differences in peak nEMG of the adductor longus between the exercises, with values ranging from 14% to 108% nEMG (pinjuries. The Copenhagen Adduction and the hip adduction with an elastic band are dynamic high-intensity exercises, which can easily be performed at any training facility and could therefore be relevant to include in future prevention and treatment programmes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  15. Features extraction and multi-classification of sEMG using a GPU-Accelerated GA/MLP hybrid algorithm.

    Science.gov (United States)

    Luo, Weizhen; Zhang, Zhongnan; Wen, Tingxi; Li, Chunfeng; Luo, Ziheng

    2017-01-01

    Surface electromyography (sEMG) signal is the combined effect of superficial muscle EMG and neural electrical activity. In recent years, researchers did large amount of human-machine system studies by using the physiological signals as control signals. To develop and test a new multi-classification method to improve performance of analyzing sEMG signals based on public sEMG dataset. First, ten features were selected as candidate features. Second, a genetic algorithm (GA) was applied to select representative features from the initial ten candidates. Third, a multi-layer perceptron (MLP) classifier was trained by the selected optimal features. Last, the trained classifier was used to predict the classes of sEMG signals. A special graphics processing unit (GPU) was used to speed up the learning process. Experimental results show that the classification accuracy of the new method reached higher than 90%. Comparing to other previously reported results, using the new method yielded higher performance. The proposed features selection method is effective and the classification result is accurate. In addition, our method could have practical application value in medical prosthetics and the potential to improve robustness of myoelectric pattern recognition.

  16. Transradial Amputee Gesture Classification Using an Optimal Number of sEMG Sensors: An Approach Using ICA Clustering.

    Science.gov (United States)

    Naik, Ganesh R; Al-Timemy, Ali H; Nguyen, Hung T

    2016-08-01

    Surface electromyography (sEMG)-based pattern recognition studies have been widely used to improve the classification accuracy of upper limb gestures. Information extracted from multiple sensors of the sEMG recording sites can be used as inputs to control powered upper limb prostheses. However, usage of multiple EMG sensors on the prosthetic hand is not practical and makes it difficult for amputees due to electrode shift/movement, and often amputees feel discomfort in wearing sEMG sensor array. Instead, using fewer numbers of sensors would greatly improve the controllability of prosthetic devices and it would add dexterity and flexibility in their operation. In this paper, we propose a novel myoelectric control technique for identification of various gestures using the minimum number of sensors based on independent component analysis (ICA) and Icasso clustering. The proposed method is a model-based approach where a combination of source separation and Icasso clustering was utilized to improve the classification performance of independent finger movements for transradial amputee subjects. Two sEMG sensor combinations were investigated based on the muscle morphology and Icasso clustering and compared to Sequential Forward Selection (SFS) and greedy search algorithm. The performance of the proposed method has been validated with five transradial amputees, which reports a higher classification accuracy ( > 95%). The outcome of this study encourages possible extension of the proposed approach to real time prosthetic applications.

  17. A mechatronics platform to study prosthetic hand control using EMG signals.

    Science.gov (United States)

    Geethanjali, P

    2016-09-01

    In this paper, a low-cost mechatronics platform for the design and development of robotic hands as well as a surface electromyogram (EMG) pattern recognition system is proposed. This paper also explores various EMG classification techniques using a low-cost electronics system in prosthetic hand applications. The proposed platform involves the development of a four channel EMG signal acquisition system; pattern recognition of acquired EMG signals; and development of a digital controller for a robotic hand. Four-channel surface EMG signals, acquired from ten healthy subjects for six different movements of the hand, were used to analyse pattern recognition in prosthetic hand control. Various time domain features were extracted and grouped into five ensembles to compare the influence of features in feature-selective classifiers (SLR) with widely considered non-feature-selective classifiers, such as neural networks (NN), linear discriminant analysis (LDA) and support vector machines (SVM) applied with different kernels. The results divulged that the average classification accuracy of the SVM, with a linear kernel function, outperforms other classifiers with feature ensembles, Hudgin's feature set and auto regression (AR) coefficients. However, the slight improvement in classification accuracy of SVM incurs more processing time and memory space in the low-level controller. The Kruskal-Wallis (KW) test also shows that there is no significant difference in the classification performance of SLR with Hudgin's feature set to that of SVM with Hudgin's features along with AR coefficients. In addition, the KW test shows that SLR was found to be better in respect to computation time and memory space, which is vital in a low-level controller. Similar to SVM, with a linear kernel function, other non-feature selective LDA and NN classifiers also show a slight improvement in performance using twice the features but with the drawback of increased memory space requirement and time

  18. Automated Algorithm for Generalized Tonic–Clonic Epileptic Seizure Onset Detection Based on sEMG Zero-Crossing Rate

    DEFF Research Database (Denmark)

    Conradsen, Isa; Beniczky, Sándor; Hoppe, Karsten

    2012-01-01

    Patients are not able to call for help during a generalized tonic–clonic epileptic seizure. Our objective was to develop a robust generic algorithm for automatic detection of tonic–clonic seizures, based on surface electromyography (sEMG) signals suitable for a portable device. Twenty-two seizure...

  19. FATIGUE ASSOCIATED EMG BEHAVIOR OF THE FIRST DORSAL INTEROSSEOUS AND ADDUCTOR POLLICIS MUSCLES IN DIFFERENT GROUPS OF SUBJECTS

    NARCIS (Netherlands)

    ZIJDEWIND, Inge; KERNELL, D

    We have studied the fatigue-associated behavior of surface EMG in two histochemically different muscles of the hand: fi rst dorsal interosseous (FDI) and adductor pollicis (AP; relatively more type I fibers in AP than in FDI). During a fatigue test evoked by electrical stimulation of the ulnar

  20. Variabilidade de parâmetros eletromiográficos e cinemáticos em diferentes condições de marcha em idosos Electromyographic and kinematic parameters variability in different conditions of motion in the elderly

    Directory of Open Access Journals (Sweden)

    Camilla Zamfolini Hallal

    2013-03-01

    Full Text Available O objetivo deste estudo foi investigar a influência do medo de cair e da dupla tarefa sobre a variabilidade de parâmetros eletromiográficos e cinemáticos da marcha de idosas. Dezessete universitárias (21,47 ± 2,06 anos e dezoito idosas (65,33 ± 3,14 anos, fisicamente ativas, realizaram teste de marcha em três condições: velocidade de preferência; medo de cair; e dupla tarefa. A atividade eletromiográfica dos músculos do membro inferior dominante e o comprimento e tempo de passada foram registrados. Utilizou-se o teste ANOVA Two-Way (pThe main goal of this study was to investigate the influence of fear of fall and dual task on electromyographic and kinematic variability parameters on the gait of older females. Seventeen college students (21,47 ± 2,06 years old and eighteen older female adults, both groups were physically fit and performed the gait test on three different conditions: walking at self-select speed, fear of fall and dual task. Electromyographic activity was measured on muscles of dominant leg and stride time was recorded. ANOVA two-way (p<0.05 was used. Electromyographic and kinematic gait variability were higher in older adult groups. However, for the comparison between gait conditions was only found significant difference for electromyographic variability. In line with this, the higher EMG and kinematic variability in older adults suggest that aging contributes for a higher motor challenge while walking, which may be predispose these individuals a higher risk of fall.

  1. A Spiking Neural Network in sEMG Feature Extraction.

    Science.gov (United States)

    Lobov, Sergey; Mironov, Vasiliy; Kastalskiy, Innokentiy; Kazantsev, Victor

    2015-11-03

    We have developed a novel algorithm for sEMG feature extraction and classification. It is based on a hybrid network composed of spiking and artificial neurons. The spiking neuron layer with mutual inhibition was assigned as feature extractor. We demonstrate that the classification accuracy of the proposed model could reach high values comparable with existing sEMG interface systems. Moreover, the algorithm sensibility for different sEMG collecting systems characteristics was estimated. Results showed rather equal accuracy, despite a significant sampling rate difference. The proposed algorithm was successfully tested for mobile robot control.

  2. EMG Pattern Recognition based on Evidence Accumulation for Prosthesis Control

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.P. [Daewoo Electronics Co., Ltd., Seoul (Korea, Republic of); Park, S.H. [Yonsei University, Seoul (Korea, Republic of)

    1997-12-01

    We present a method of electromyography(EMG) pattern recognition to identify motion commands for the control of a prosthetic arm by evidence accumulation with multiple parameters. Integral absolute value, variance, autoregressive(AR) model coefficients, linear cepstrum coefficients, and adaptive cepstrum vector are extracted as feature parameters from several time segments of the EMG signals. Pattern recognition is carried out through the evidence accumulation procedure using the distances measured with reference parameters. A fuzzy mapping function is designed to transform the distances for the application of the evidence accumulation method. Results are presented to support the feasibility of the suggested approach for EMG pattern recognition. (author). 29 refs., 11 figs., 7 tabs.

  3. Variability of cardio-respiratory, electromyographic, and perceived exertion responses at the walk-run transition in a sample of young men controlled for anthropometric and fitness characteristics.

    Science.gov (United States)

    Monteiro, Walace D; Farinatti, Paulo T V; de Oliveira, Carlos G; Araújo, Claudio Gil S

    2011-06-01

    The cardio-respiratory (heart rate, HR; oxygen uptake, VO(2;) expired carbon dioxide, VCO(2); ventilation, VE), electromyographic (EMG; medial gastrocnemius, vastus lateralis, rectus femoralis, and anterior tibialis), and perceived exertion (PE) responses during a protocol for the determination of the walk-run transition speed (WRTS) were investigated. From an initial sample of 453 volunteers, 12 subjects matched for age, anthropometric characteristics [height, weight, lower limb length (LLL)], cardio-respiratory fitness (peak oxygen consumption, VO(2peak); ventilatory threshold, VT; maximal HR), and habitual physical activity levels were selected (age = 18.6 ± 0.5 years; height = 174.5 ± 1.4 cm; weight = 66.4 ± 1.1 kg; LLL = 83.3 ± 1.2 cm, VO(2peak) = 52.2 ± 2.2 ml kg(-1) min(-1); VT = 39.8 ± 2.6 ml kg(-1) min(-1)). The highly reproducible WRTS determination protocol (ICC = 0.92; p Cardio-respiratory responses at WRTS had a greater variation (VO(2) about 50%; VE/VCO(2) about 35%; VE/VO(2) about 45%; HR about 30%). The highest variation was found for PE (from 70 to 90%) whereas EMG variables showed the lowest variation (from 25 to 30%). Linear regression between EMG series and VO(2) data showed that VO(2) reflected the increase in muscle activity only before the WRTS. These results support the hypothesis that the walk-run transition phenomenon is determined by mechanical variables such as limb length and its relationship to biomechanical model rather than by metabolic factors.

  4. A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions.

    Science.gov (United States)

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2015-01-01

    Background. The purpose of this study was to compare the peak electromyography (EMG) of the most commonly-used position in the literature, the prone bent-leg (90°) hip extension against manual resistance applied to the distal thigh (PRONE), to a novel position, the standing glute squeeze (SQUEEZE). Methods. Surface EMG electrodes were placed on the upper and lower gluteus maximus of thirteen recreationally active females (age = 28.9 years; height = 164 cm; body mass = 58.2 kg), before three maximum voluntary isometric contraction (MVIC) trials for each position were obtained in a randomized, counterbalanced fashion. Results. No statistically significant (p gluteus maximus. Neither the PRONE nor SQUEEZE was more effective between all subjects. Conclusions. In agreement with other studies, no single testing position is ideal for every participant. Therefore, it is recommended that investigators employ multiple MVIC positions, when possible, to ensure accuracy. Future research should investigate a variety of gluteus maximus MVIC positions in heterogeneous samples.

  5. Electromyographic Comparison of Elastic Resistance and Machine Exercises for High-Intensity Strength Training in Patients With Chronic Stroke.

    Science.gov (United States)

    Vinstrup, Jonas; Calatayud, Joaquin; Jakobsen, Markus D; Sundstrup, Emil; Jay, Kenneth; Brandt, Mikkel; Zeeman, Peter; Jørgensen, Jørgen R; Andersen, Lars L

    2016-03-01

    To investigate whether elastic resistance training can induce comparable levels of muscle activity as conventional machine training in patients with chronic stroke. Comparative study. Outpatient rehabilitation facility. Stroke patients (N=18) with hemiparesis (mean age, 57 ± 8y). Patients performed 3 consecutive repetitions at 10 repetition maximum of unilateral knee extension and flexion using elastic resistance and conventional machine training. Surface electromyography was measured in vastus lateralis, vastus medialis, biceps femoris, and semitendinosus and was normalized to maximal electromyography (% of max) of the nonparetic leg. In the paretic leg, agonist muscle activity ranged from 18% to 24% normalized electromyography (% of max) (nEMG) during knee flexion and from 32% to 40% nEMG during knee extension. For knee extension, vastus lateralis nEMG was higher during machine exercise than during elastic resistance exercise (40% [95% confidence interval {CI}, 33-47] vs 32% [95% CI, 25-39]; P=.003). In the nonparetic leg, agonist muscle activity ranged from 54% to 61% during knee flexion and from 52% to 68% during knee extension. For knee flexion semitendinosus nEMG was higher (61% [95% CI, 50-71] vs 54% [95% CI, 44-64]; P=.016) and for knee extension vastus medialis nEMG was higher (68% [95% CI, 60-76] vs 56% [95% CI, 48-64]; Ptraining appears to induce slightly higher levels of muscle activity in some of the investigated muscles compared to elastic resistance during lower limb strength training in patients with chronic stroke. The higher level of coactivation during knee flexion when performed using elastic resistance suggests that elastic resistance exercises are more difficult to perform. This is likely due to a higher level of movement instability. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  6. Análise do padrão eletromiográfico durante os agachamentos padrão e declinado Analysis of electromyographic patterns during standard and declined squats

    Directory of Open Access Journals (Sweden)

    FSM Alves

    2009-04-01

    Full Text Available OBJETIVO: Identificar e comparar o padrão eletromiográfico (EMG dos principais músculos do membro inferior com apoio bilateral durante o agachamento padrão e declinado. MÉTODOS: Foram recrutados oito sujeitos (três homens e cinco mulheres, todos destros, atletas de final de semana e saudáveis (médias: 20,57 anos; 69,5±15kg; 1,73±0,15m. Foram registrados os sinais eletromiográficos dos músculos vasto medial oblíquo (VMO, vasto lateral (VL, bíceps femoral (BF, sóleo (SO, tibial anterior (TA e eretor espinhal (EE durante a fase ascendente (70º-0º e descendente (0º-70º dos agachamentos padrão (plano horizontal e declinado (a 25º. A integral da atividade EMG de cada músculo foi calculada no intervalo de 300 milisegundos (ms antes do início e do final do movimento. A média de cada músculo para cada sujeito foi analisada pelo teste de análise de variância para medidas repetidas (ANOVA para verificar o efeito da tarefa de agachar. RESULTADOS:A análise qualitativa revelou que o padrão de atividade muscular durante os agachamentos padrão e declinado foram similares, e a análise quantitativa não revelou diferenças na atividade EMG. CONCLUSÃO: Os resultados demonstram que a atividade EMG dos músculos estudados foi similar entre as tarefas propostas.OBJECTIVE: To identify and compare the electromyographic (EMG pattern of the main muscles of the lower limbs with bilateral support during standard and declined squats. METHODS:Eight healthy subjects were recruited (three men and five women, all right-handed and weekend athletes (means: 20.57 years; 69.5±15kg; 1.73±0.15m. Electromyographic (EMG signals from the vastus medialis obliquus (VMO, vastus lateralis (VL, biceps femoris (BF, soleus (SO, tibialis anterior (TA and erector spinae (ES muscles were recorded during the ascending (70º-0º and descending (0º-70º phases of the standard squat (horizontal plane and declined squat (at 25º. The integral of the EMG activity for

  7. siGnum: graphical user interface for EMG signal analysis.

    Science.gov (United States)

    Kaur, Manvinder; Mathur, Shilpi; Bhatia, Dinesh; Verma, Suresh

    2015-01-01

    Electromyography (EMG) signals that represent the electrical activity of muscles can be used for various clinical and biomedical applications. These are complicated and highly varying signals that are dependent on anatomical location and physiological properties of the muscles. EMG signals acquired from the muscles require advanced methods for detection, decomposition and processing. This paper proposes a novel Graphical User Interface (GUI) siGnum developed in MATLAB that will apply efficient and effective techniques on processing of the raw EMG signals and decompose it in a simpler manner. It could be used independent of MATLAB software by employing a deploy tool. This would enable researcher's to gain good understanding of EMG signal and its analysis procedures that can be utilized for more powerful, flexible and efficient applications in near future.

  8. Test-retest reliability of cardinal plane isokinetic hip torque and EMG.

    Science.gov (United States)

    Claiborne, Tina L; Timmons, Mark K; Pincivero, Danny M

    2009-10-01

    The objective of the present study was to establish test-retest reliability of isokinetic hip torque and prime mover electromyogram (EMG) through the three cardinal planes of motion. Thirteen healthy young adults participated in two experimental sessions, separated by approximately one week. During each session, isokinetic hip torque was evaluated on the Biodex Isokinetic Dynamometer at a velocity of 60 deg/s. Subjects performed three maximal-effort concentric and eccentric contractions, separately, for right and left hip abduction/adduction, flexion/extension, and internal/external rotation. Surface EMGs were sampled from the gluteus maximus, gluteus medius, adductor, medial and lateral hamstring, and rectus femoris muscles during all contractions. Intraclass correlation coefficients (ICC - 2,1) and standard errors of measurement (SEM) were calculated for peak torque for each movement direction and contraction mode, while ICCs were only computed for the EMG data. Motions that demonstrated high torque reliability included concentric hip abduction (right and left), flexion (right and left), extension (right) and internal rotation (right and left), and eccentric hip abduction (left), adduction (left), flexion (right), and extension (right and left) (ICC range=0.81-0.91). Motions with moderate torque reliability included concentric hip adduction (right), extension (left), internal rotation (left), and external rotation (right), and eccentric hip abduction and adduction (right), flexion (left), internal rotation (right and left), and external rotation (right and left) (ICC range=0.49-0.79). The majority of the EMG sampled muscles (n=12 and n=11 for concentric and eccentric contractions, respectively) demonstrated high reliability (ICC=0.81-0.95). Instances of low, or unacceptable, EMG reliability values occurred for the medial hamstring muscle of the left leg (both contraction modes) and the adductor muscle of the right leg during eccentric internal rotation. The major

  9. An electromyographic study of the hip muscles of transfemoral amputees in walking

    NARCIS (Netherlands)

    Jaegers, SMHJ; Arendzen, JH; deJongh, HJ

    The aim of this study was to obtain insight into the electromyographic activity of the hip muscles after transfemoral amputation and to determine whether the cleaved hip muscles are still functional in locomotion, The electromyographic activity of the superficial hip muscles of both legs was studied

  10. Contemporary linkages between EMG, kinetics and stroke rehabilitation

    OpenAIRE

    Wolf, Steven L.; Butler, Andrew J.; Alberts, Jay L.; Kim, Min Wook

    2005-01-01

    EMG and kinetic measures have been primary tools in the study of movement and have provided the foundation for much of the work presented in this journal. Recently, novel ways of combining these tools have provided opportunities to examine elements of motor learning and brain plasticity. This presentation reviews the quantification of EMG within the context of transcranial magnetic stimulation. This vehicle permits acquisition of measures that are fundamental to examining prospects for cortic...

  11. Anal sphincter EMG in the diagnosis of parkinsonian syndromes

    DEFF Research Database (Denmark)

    Winge, K; Jennum, Poul Jørgen; Løkkegaard, Annemette

    2010-01-01

    The role of electromyography (EMG) recorded from the external anal sphincter (EAS) in the diagnosis of atypical parkinsonian syndromes is a matter for continuous debate. Most studies addressing this issue are retrospective.......The role of electromyography (EMG) recorded from the external anal sphincter (EAS) in the diagnosis of atypical parkinsonian syndromes is a matter for continuous debate. Most studies addressing this issue are retrospective....

  12. Electromyographic Analysis of the Hip Extension Pattern in Visually Impaired Athletes.

    Science.gov (United States)

    Halski, Tomasz; Żmijewski, Piotr; Cięszczyk, Paweł; Nowak, Barbara; Ptaszkowski, Kuba; Slupska, Lucyna; Dymarek, Robert; Taradaj, Jakub

    2015-11-22

    The objective of the study was to determine the order of muscle recruitment during the active hip joint extension in particular positions in young visually impaired athletes. The average recruitment time (ART) of the gluteus maximus (GM) and the hamstring muscle group (HMG) was assessed by the means of surface electromyography (sEMG). The sequence of muscle recruitment in the female and male group was also taken into consideration. This study followed a prospective, cross - sectional, randomised design, where 76 visually impaired athletes between the age of 18-25 years were enrolled into the research and selected on chosen inclusion and exclusion criteria. Finally, 64 young subjects (32 men and 32 women) were included in the study (age: 21.1 ± 1.05 years; body mass: 68.4 ± 12.4 kg; body height: 1.74 ± 0.09 m; BMI: 22.20 ± 2.25 kg/m2). All subjects were analysed for the ART of the GM and HMG during the active hip extension performed in two different positions, as well as resting and functional sEMG activity of each muscle. Between gender differences were comprised and the correlations between the ART of the GM and HMG with their functional sEMG activity during hip extension in both positions were shown. No significant differences between the ART of the GM and HMG were found (p>0.05). Furthermore, there was no significant difference of ART among both tested positions, as well in male as female subjects (p>0.05).

  13. Electromyographic Analysis of the Hip Extension Pattern in Visually Impaired Athletes

    Directory of Open Access Journals (Sweden)

    Halski Tomasz

    2015-12-01

    Full Text Available The objective of the study was to determine the order of muscle recruitment during the active hip joint extension in particular positions in young visually impaired athletes. The average recruitment time (ART of the gluteus maximus (GM and the hamstring muscle group (HMG was assessed by the means of surface electromyography (sEMG. The sequence of muscle recruitment in the female and male group was also taken into consideration. This study followed a prospective, cross – sectional, randomised design, where 76 visually impaired athletes between the age of 18–25 years were enrolled into the research and selected on chosen inclusion and exclusion criteria. Finally, 64 young subjects (32 men and 32 women were included in the study (age: 21.1 ± 1.05 years; body mass: 68.4 ± 12.4 kg; body height: 1.74 ± 0.09 m; BMI: 22.20 ± 2.25 kg/m2. All subjects were analysed for the ART of the GM and HMG during the active hip extension performed in two different positions, as well as resting and functional sEMG activity of each muscle. Between gender differences were comprised and the correlations between the ART of the GM and HMG with their functional sEMG activity during hip extension in both positions were shown. No significant differences between the ART of the GM and HMG were found (p>0.05. Furthermore, there was no significant difference of ART among both tested positions, as well in male as female subjects (p>0.05.

  14. Ontogenetic Changes in Mammalian Feeding: Insights from Electromyographic Data

    OpenAIRE

    Campbell-Malone, Regina; Crompton, Alfred W.; Thexton, Allan J.; German, Rebecca Z.

    2011-01-01

    All infant mammals make a transition from suckling milk to eating solid foods. Yet, the neuromuscular implications of the transition from a liquid-only diet to solid foods are unknown even though the transport and swallowing of liquids is different from that of solids. We used legacy electromyography (EMG) data to test hypotheses concerning the changes in motor pattern and neuromuscular control that occur during the transition from an all-liquid diet to consumption of solid food in a porcine ...

  15. Uncoupling of in vivo torque production from EMG in mouse muscles injured by eccentric contractions

    Science.gov (United States)

    Warren, Gordon L; Ingalls, Christopher P; Shah, Shree J; Armstrong, R B

    1999-01-01

    The main objective of this study was to determine whether eccentric contraction-induced muscle injury causes impaired plasmalemmal action potential conduction, which could explain the injury-induced excitation-contraction coupling failure. Mice were chronically implanted with stimulating electrodes on the left common peroneal nerve and with electromyographic (EMG) electrodes on the left tibialis anterior (TA) muscle. The left anterior crural muscles of anaesthetized mice were stimulated to perform 150 eccentric (ECC) (n = 12 mice) or 150 concentric (CON) (n = 11 mice) contractions. Isometric torque, EMG root mean square (RMS) and M-wave mean and median frequencies were measured before, immediately after, and at 1, 3, 5 and 14 days after the protocols. In parallel experiments, nicotinic acetylcholine receptor (AChR) concentration was measured in TA muscles to determine whether the excitation failure elicited a denervation-like response.Immediately after the ECC protocol, torque was reduced by 47–89%, while RMS was reduced by 9–21%; the RMS decrement was not different from that observed for the CON protocol, which did not elicit large torque deficits. One day later, both ECC and CON RMS had returned to baseline values and did not change over the next 2 weeks. However, torque production by the ECC group showed a slow recovery over that time and was still depressed by 12–30% after 2 weeks. M-wave mean and median frequencies were not affected by performance of either protocol.AChR concentration was elevated by 79 and 368% at 3 and 5 days, respectively, after the ECC protocol; AChR concentration had returned to control levels 2 weeks after the protocol. At the time of peak AChR concentration in the ECC protocol muscles (i.e. 5 days), AChR concentration in CON protocol muscles was not different from the control level.In conclusion, these data demonstrate no major role for impaired plasmalemmal action potential conduction in the excitation-contraction coupling

  16. Electromyographic analysis of shoulder joint function of the biceps brachii muscle during isometric contraction.

    Science.gov (United States)

    Sakurai, G; Ozaki, J; Tomita, Y; Nishimoto, K; Tamai, S

    1998-09-01

    Surface electromyography was performed for both heads of the biceps brachii in 11 healthy men while the muscles were under 30% maximum isometric shoulder flexion and abduction. Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation. Electromyographic activity was normalized as a percentage of maximal muscle contraction during 24 shoulder motions. Electromyographic activity was detected in all motions examined, suggesting that the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of the biceps muscle had higher activities during external rotation than during internal rotation for most motions. Activities of both heads increased with arm elevation, but showed little dependence on elbow position. The long head was still active during internal rotation of the shoulder. These findings also suggest that the biceps muscle is a flexor and an abductor of the shoulder, and that the long head can act as a humeral head stabilizer in superior and anterior directions. Muscle fatigue of the biceps and the deltoid muscle also was determined at 30% of maximum isometric flexion. All muscles had significantly decreased mean power frequency and turns count, and increased amplitude and integrated electromyography. The rate of decrease in mean power frequency was larger for the biceps than for the deltoid muscle, and the rate of increase in amplitude was larger for the long head of the biceps than for the short head or for the deltoid muscle. These findings suggest that the long head of the biceps must increase its mechanical output to keep the arm in elevation to a greater extent than do the short head and the deltoid muscle. This may be one of the causes of tendinitis or rupture of the long head.

  17. Speedup computation of HD-sEMG signals using a motor unit-specific electrical source model.

    Science.gov (United States)

    Carriou, Vincent; Boudaoud, Sofiane; Laforet, Jeremy

    2018-01-23

    Nowadays, bio-reliable modeling of muscle contraction is becoming more accurate and complex. This increasing complexity induces a significant increase in computation time which prevents the possibility of using this model in certain applications and studies. Accordingly, the aim of this work is to significantly reduce the computation time of high-density surface electromyogram (HD-sEMG) generation. This will be done through a new model of motor unit (MU)-specific electrical source based on the fibers composing the MU. In order to assess the efficiency of this approach, we computed the normalized root mean square error (NRMSE) between several simulations on single generated MU action potential (MUAP) using the usual fiber electrical sources and the MU-specific electrical source. This NRMSE was computed for five different simulation sets wherein hundreds of MUAPs are generated and summed into HD-sEMG signals. The obtained results display less than 2% error on the generated signals compared to the same signals generated with fiber electrical sources. Moreover, the computation time of the HD-sEMG signal generation model is reduced to about 90% compared to the fiber electrical source model. Using this model with MU electrical sources, we can simulate HD-sEMG signals of a physiological muscle (hundreds of MU) in less than an hour on a classical workstation. Graphical Abstract Overview of the simulation of HD-sEMG signals using the fiber scale and the MU scale. Upscaling the electrical source to the MU scale reduces the computation time by 90% inducing only small deviation of the same simulated HD-sEMG signals.

  18. Masticatory function in temporomandibular dysfunction patients: electromyographic evaluation.

    Science.gov (United States)

    Berretin-Felix, Giédre; Genaro, Katia Flores; Trindade, Inge Elly Kiemle; Trindade Júnior, Alceu Sergio

    2005-12-01

    Temporomandibular dysfunction (TMD) is a complex disturbance that involves the masticatory muscles and/or temporomandibular joint, causing damage to the masticatory function. This study evaluated the electromyographic activity of the masseter muscle during habitual mastication of bread, apple, banana, cashew nut and paraffin film (Parafilm M) in 25 adult subjects, of both gender, with TMD. The results were compared to those of a control group, composed of 15 adult subjects, of both sexes, free of signs and/or symptoms of TMD. The MYO-TRONICS Inc., K6-I computer software was used for electromyographic processing and analyzed the following parameters: duration of the act, duration of the masticatory cycle and number of cycles. No significant differences were found between subjects in the control group and individuals with TMD as to duration of the masticatory act and of the masticatory cycle, considering all materials used for mastication. The duration of the masticatory act and cycle was longer during mastication of paraffin film in both groups. The number of masticatory cycles was higher for mastication of apple in comparison to mastication of banana, in both groups. It can be concluded that the consistency of foods influences the duration parameters of the act, duration of the cycle and the number of masticatory cycles, and the behavior of the masticatory muscles in individuals with TMD during habitual mastication is similar to that verified in individuals without TMD.

  19. Computational Intelligence Based Data Fusion Algorithm for Dynamic sEMG and Skeletal Muscle Force Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekhar Potluri,; Madhavi Anugolu; Marco P. Schoen; D. Subbaram Naidu

    2013-08-01

    In this work, an array of three surface Electrography (sEMG) sensors are used to acquired muscle extension and contraction signals for 18 healthy test subjects. The skeletal muscle force is estimated using the acquired sEMG signals and a Non-linear Wiener Hammerstein model, relating the two signals in a dynamic fashion. The model is obtained from using System Identification (SI) algorithm. The obtained force models for each sensor are fused using a proposed fuzzy logic concept with the intent to improve the force estimation accuracy and resilience to sensor failure or misalignment. For the fuzzy logic inference system, the sEMG entropy, the relative error, and the correlation of the force signals are considered for defining the membership functions. The proposed fusion algorithm yields an average of 92.49% correlation between the actual force and the overall estimated force output. In addition, the proposed fusionbased approach is implemented on a test platform. Experiments indicate an improvement in finger/hand force estimation.

  20. Neuromuscular interfacing: a novel approach to EMG-driven multiple DOF physiological models.

    Science.gov (United States)

    Pau, James W L; Xie, Shane S Q; Xu, W L

    2013-01-01

    This paper presents a novel approach that involves first identifying and verifying the available superficial muscles that can be recorded by surface electromyography (EMG) signals, and then developing a musculoskeletal model based on these findings, which have specifically independent DOFs for movement. Such independently controlled multiple DOF EMG-driven models have not been previously developed and a two DOF model for the masticatory system was achieved by implementing independent antagonist muscle combinations for vertical and lateral movements of the jaw. The model has six channels of EMG signals from the bilateral temporalis, masseter and digastric muscles to predict the motion of the mandible. This can be used in a neuromuscular interface to manipulate a jaw exoskeleton for rehabilitation. For a range of different complexities of jaw movements, the presented model is able to consistently identify movements with 0.28 - 0.46 average normalized RMSE. The results demonstrate the feasibility of the approach at determining complex multiple DOF movements and its applicability to any joint system.

  1. Electromyographic validation of basic exercises for physical conditioning programmes. IV. Analysis of the deltoid muscle (anterior portion) and pectoralis major muscle (clavicular portion) in frontal-lateral cross, dumbbells exercises.

    Science.gov (United States)

    Ferreira, M I; Büll, M L; Vitti, M

    2003-03-01

    The electromyographic activity of the shoulder muscles deltoid--anterior portion (DA) and pectoralis major--clavicular portion (PMC) was tested on 24 male volunteers using a 2 channel TECA TE4 electromyograph and Hewlett Packard surface electrodes during the execution of four different modalities of frontal-lateral cross, dumbbells exercises. The results showed that all of the tested exercises developed high levels of action potential for both muscles. So, we justify the indication of all of them for physical fitness programmes for DA and PMC. Some suggestions to the use of the tested exercises are presented.

  2. Electromyographic analysis of gluteus medius and gluteus maximus during rehabilitation exercises.

    Science.gov (United States)

    Boren, Kristen; Conrey, Cara; Le Coguic, Jennifer; Paprocki, Lindsey; Voight, Michael; Robinson, T Kevin

    2011-09-01

    Previous research studies by Bolga, Ayotte, and Distefano have examined the level of muscle recruitment of the gluteal muscles for various clinical exercises; however, there has been no cross comparison among the top exercises from each study. The purpose of this study is to compare top exercises from these studies as well as several other commonly performed clinical exercises to determine which exercises recruit the gluteal muscles, specifically the gluteus medius and maximus, most effectively. Twenty-six healthy subjects participated in this study. Surface EMG electrodes were placed on gluteus medius and maximus to measure muscle activity during 18 exercises. Maximal voluntary muscle contraction (MVIC) was established for each muscle group in order to express each exercise as a percentage of MVIC and allow standardized comparison across subjects. EMG data were analyzed using a root-mean-square algorithm and smoothed with a 50 millisecond time reference. Rank ordering of the exercises was performed utilizing the average percent MVIC peak activity for each exercise. Twenty-four subjects satisfied all eligibility criteria and consented to participate in the research study. Five of the exercises produced greater than 70%MVIC of the gluteus medius muscle. In rank order from highest EMG value to lowest, these exercises were: side plank abduction with dominant leg on bottom (103%MVIC), side plank abduction with dominant leg on top (89%MVIC), single limb squat (82%MVIC), clamshell (hip clam) progression 4 (77%MVIC), and font plank with hip extension (75%MVIC). Five of the exercises recruited gluteus maximus with values greater than 70%MVIC. In rank order from highest EMG value to lowest, these exercises were: front plank with hip extension (106%MVIC), gluteal squeeze (81%MVIC), side plank abduction with dominant leg on top (73%MVIC), side plank abduction with dominant leg on bottom (71%MVIC), and single limb squat (71%MVIC). Four of the exercises produced greater than 70

  3. EMG-Torque correction on Human Upper extremity using Evolutionary Computation

    Science.gov (United States)

    JL, Veronica; Parasuraman, S.; Khan, M. K. A. Ahamed; Jeba DSingh, Kingsly

    2016-09-01

    There have been many studies indicating that control system of rehabilitative robot plays an important role in determining the outcome of the therapy process. Existing works have done the prediction of feedback signal in the controller based on the kinematics parameters and EMG readings of upper limb's skeletal system. Kinematics and kinetics based control signal system is developed by reading the output of the sensors such as position sensor, orientation sensor and F/T (Force/Torque) sensor and there readings are to be compared with the preceding measurement to decide on the amount of assistive force. There are also other works that incorporated the kinematics parameters to calculate the kinetics parameters via formulation and pre-defined assumptions. Nevertheless, these types of control signals analyze the movement of the upper limb only based on the movement of the upper joints. They do not anticipate the possibility of muscle plasticity. The focus of the paper is to make use of the kinematics parameters and EMG readings of skeletal system to predict the individual torque of upper extremity's joints. The surface EMG signals are fed into different mathematical models so that these data can be trained through Genetic Algorithm (GA) to find the best correlation between EMG signals and torques acting on the upper limb's joints. The estimated torque attained from the mathematical models is called simulated output. The simulated output will then be compared with the actual individual joint which is calculated based on the real time kinematics parameters of the upper movement of the skeleton when the muscle cells are activated. The findings from this contribution are extended into the development of the active control signal based controller for rehabilitation robot.

  4. Facial EMG responses to odors in solitude and with an audience.

    Science.gov (United States)

    Jäncke, L; Kaufmann, N

    1994-04-01

    Two experiments were undertaken to examine whether facial responses to odors correlate with the hedonic odor evaluation. Experiment 1 examined whether subjects (n = 20) spontaneously generated facial movements associated with odor evaluation when they are tested in private. To measure facial responses, EMG was recorded over six muscle regions (M. corrugator supercilii, M. procerus, M. nasalis, M. levator, M. orbicularis oculi and M. zygomaticus major) using surface electrodes. In experiment 2 the experimental group (n = 10) smelled the odors while they were visually inspected by the experimenter sitting in front of the test subjects. The control group (n = 10) performed the same experimental condition as those subjects participating in experiment 1. Facial EMG over four mimetic muscle regions (M. nasalis, M. levator, M. zygomaticus major, M. orbicularis oculi) was measured while subjects smelled different odors. The main findings of this study may be summarized as follows: (i) there was no correlation between valence rating and facial EMG responses; (ii) pleasant odors did not evoke smiles when subjects smelled the odors in private; (iii) in solitude, highly concentrated malodors evoked facial EMG reactions of those mimetic muscles which are mainly involved in generating a facial display of disgust; (iv) those subjects confronted with an audience showed stronger facial reactions over the periocular and cheek region (indicative of a smile) during the smelling of pleasant odors than those who smelled these odors in private; (v) those subjects confronted with an audience showed stronger facial reactions over the M. nasalis region (indicative of a display of disgust) during the smelling of malodors than those who smelled the malodors in private. These results were taken as evidence for a more social communicative function of facial displays and strongly mitigates the reflexive-hedonic interpretation of facial displays to odors as supposed by Steiner.

  5. Fatigue sensation, electromyographical and hemodynamic changes of low back muscles during repeated static contraction.

    Science.gov (United States)

    Movahed, Mehrnoosh; Ohashi, Jun-ya; Kurustien, Nopporn; Izumi, Hiroyuki; Kumashiro, Masaharu

    2011-03-01

    The effects of work strategy and a rest condition on the physiological changes of the erector spinae muscle were studied. Eleven volunteers repeated fatiguing static contractions of holding an industrial box in 30° trunk flexion for a repetition of 12 times interrupted by rests for which the duration was equal to the duration of each preceding contraction. Each contraction was stopped at two fatigue sensation levels; moderate or strong, which corresponded to Borg's CR-10 3 and 5, as the work strategy conditions. The repeated contractions were performed for a total of eight conditions combined with the two rest conditions, with and without stretch exercise, and two contraction levels of 10 and 40% maximum pulling force in flexed posture (MVC) on separate days. Near-infrared spectroscopy and surface electromyography (EMG) were recorded. Amplitude and median frequency (MF) of EMG, oxy-hemoglobin, and deoxy-hemoglobin were calculated. MF related to fatigue sensation most closely. Oxy-hemoglobin decreased during each contraction. It, however, increased with repetition especially at 10% MVC and the increase was interpreted as adaptation to the work. The effect of the work strategy and the rest conditions was weak. MF decreased more in a strong work strategy condition than in a moderate one.

  6. Electromyographic response of global abdominal stabilizers in response to stable- and unstable-base isometric exercise.

    Science.gov (United States)

    Atkins, Stephen J; Bentley, Ian; Brooks, Darrell; Burrows, Mark P; Hurst, Howard T; Sinclair, Jonathan K

    2015-06-01

    Core stability training traditionally uses stable-base techniques. Less is known as to the use of unstable-base techniques, such as suspension training, to activate core musculature. This study sought to assess the neuromuscular activation of global core stabilizers when using suspension training techniques, compared with more traditional forms of isometric exercise. Eighteen elite level, male youth swimmers (age, 15.5 ± 2.3 years; stature, 163.3 ± 12.7 cm; body mass, 62.2 ± 11.9 kg) participated in this study. Surface electromyography (sEMG) was used to determine the rate of muscle contraction in postural musculature, associated with core stability and torso bracing (rectus abdominus [RA], external obliques [EO], erector spinae [ES]). A maximal voluntary contraction test was used to determine peak amplitude for all muscles. Static bracing of the core was achieved using a modified "plank" position, with and without a Swiss ball, and held for 30 seconds. A mechanically similar "plank" was then held using suspension straps. Analysis of sEMG revealed that suspension produced higher peak amplitude in the RA than using a prone or Swiss ball "plank" (p = 0.04). This difference was not replicated in either the EO or ES musculature. We conclude that suspension training noticeably improves engagement of anterior core musculature when compared with both lateral and posterior muscles. Further research is required to determine how best to activate both posterior and lateral musculature when using all forms of core stability training.

  7. An electromyographic investigation of the pattern of overflow facilitated by manual resistive proprioceptive neuromuscular facilitation in young healthy individuals: a preliminary study.

    Science.gov (United States)

    Reznik, J E; Biros, E; Bartur, G

    2015-01-01

    To investigate the pattern of overflow facilitated by the use of resistive proprioceptive neuromuscular facilitation (PNF). In a group of 12 young, healthy individuals, recruitment of electrical activity into the tibialis anterior (TA) muscle of the right lower limb (RLL) was assessed using surface electromyography (sEMG) during a random-sequence application of manually-resistive PNF to the other three limbs. Resistance exercise applied to the left lower limb (LLL) was associated with a considerable increase in sEMG activity in the RLL TA muscle compared to its baseline level (p = 0.001). Resistance exercise applied to the right or left upper limbs (RUL or LUL) respectively showed similar sEMG activity in RLL TA muscle to its baseline level. A resistance exercise would appear to be effective in producing electrical activity in the contralateral homologous muscles of non-exercised limb.

  8. Simultaneous 31P NMR spectroscopy and EMG in exercising and recovering human skeletal muscle: technical aspects

    DEFF Research Database (Denmark)

    Vestergaard-Poulsen, P; Thomsen, C; Sinkjaer, T

    1994-01-01

    The bioenergetics of human skeletal muscle can be studied by 31P NMR spectroscopy (31P-MRS) and by surface electromyography (SEMG). Simultaneous 31P-MRS and SEMG permit accurate and noninvasive studies of the correlation between metabolic and electrical changes in exercising and recovering human...... skeletal muscle, a relationship that is still poorly understood. This study describes the optimization of skeletal muscle 31P-MRS in a whole-body magnet, involving surface coil design, utilization of adiabatic radio frequency pulses and advanced time-domain fitting, to the technical design of SEMG....... A nonmagnetic ergometer was used for ankle dorsiflexions that activated only the anterior tibial muscle as verified by post exercise imaging. The coil design and the adiabatic sech/tanh pulse improved sensitivity by 45% and 56% respectively, compared with standard techniques. Simultaneous electromyographic...

  9. Continuous and simultaneous estimation of finger kinematics using inputs from an EMG-to-muscle activation model.

    Science.gov (United States)

    Ngeo, Jimson G; Tamei, Tomoya; Shibata, Tomohiro

    2014-08-14

    Surface electromyography (EMG) signals are often used in many robot and rehabilitation applications because these reflect motor intentions of users very well. However, very few studies have focused on the accurate and proportional control of the human hand using EMG signals. Many have focused on discrete gesture classification and some have encountered inherent problems such as electro-mechanical delays (EMD). Here, we present a new method for estimating simultaneous and multiple finger kinematics from multi-channel surface EMG signals. In this study, surface EMG signals from the forearm and finger kinematic data were extracted from ten able-bodied subjects while they were tasked to do individual and simultaneous multiple finger flexion and extension movements in free space. Instead of using traditional time-domain features of EMG, an EMG-to-Muscle Activation model that parameterizes EMD was used and shown to give better estimation performance. A fast feed forward artificial neural network (ANN) and a nonparametric Gaussian Process (GP) regressor were both used and evaluated to estimate complex finger kinematics, with the latter rarely used in the other related literature. The estimation accuracies, in terms of mean correlation coefficient, were 0.85 ± 0.07, 0.78 ± 0.06 and 0.73 ± 0.04 for the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and the distal interphalangeal (DIP) finger joint DOFs, respectively. The mean root-mean-square error in each individual DOF ranged from 5 to 15%. We show that estimation improved using the proposed muscle activation inputs compared to other features, and that using GP regression gave better estimation results when using fewer training samples. The proposed method provides a viable means of capturing the general trend of finger movements and shows a good way of estimating finger joint kinematics using a muscle activation model that parameterizes EMD. The results from this study demonstrates a potential control

  10. Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

    Science.gov (United States)

    Hsu, Chao-Jung; Kim, Janis; Tang, Rongnian; Roth, Elliot J; Rymer, William Z; Wu, Ming

    2017-10-01

    To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  11. Electrotactile EMG feedback improves the control of prosthesis grasping force

    Science.gov (United States)

    Schweisfurth, Meike A.; Markovic, Marko; Dosen, Strahinja; Teich, Florian; Graimann, Bernhard; Farina, Dario

    2016-10-01

    Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for

  12. The Reliability of Electromyographic Normalization Methods for Cycling Analyses

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2015-06-01

    Full Text Available Electromyography (EMG is normalized in relation to a reference maximum voluntary contraction (MVC value. Different normalization techniques are available but the most reliable method for cycling movements is unknown. This study investigated the reliability of different normalization techniques for cycling analyses. Twenty-five male cyclists (age 24.13 ± 2.79 years, body height 176.22 ± 4.87 cm and body mass 67.23 ± 4.19 kg, BMI = 21.70 ± 2.60 kg·m−1 performed different normalization procedures on two occasions, within the same testing session. The rectus femoris, biceps femoris, gastrocnemius and tibialis anterior muscles were examined. Participants performed isometric normalizations (IMVC using an isokinetic dynamometer. Five minutes of submaximal cycling (180 W were also undertaken, allowing the mean (DMA and peak (PDA activation from each muscle to serve as reference values. Finally, a 10 s cycling sprint (MxDA trial was undertaken and the highest activation from each muscle was used as the reference value. Differences between reference EMG amplitude, as a function of normalization technique and time, were examined using repeated measures ANOVAs. The testretest reliability of each technique was also examined using linear regression, intraclass correlations and Cronbach’s alpha. The results showed that EMG amplitude differed significantly between normalization techniques for all muscles, with the IMVC and MxDA methods demonstrating the highest amplitudes. The highest levels of reliability were observed for the PDA technique for all muscles; therefore, our results support the utilization of this method for cycling analyses.

  13. Electromyographic studies in abdominal exercises: a literature synthesis.

    Science.gov (United States)

    Monfort-Pañego, Manuel; Vera-García, Francisco J; Sánchez-Zuriaga, Daniel; Sarti-Martínez, Maria Angeles

    2009-01-01

    The purpose of this article is to synthesize the literature on studies that investigate electromyographic activity of abdominal muscles during abdominal exercises performance. MEDLINE and Sportdiscus databases were searched, as well as the Web pages of electronic journals access, ScienceDirect, and Swetswise, from 1950 to 2008. The terms used to search the literature were abdominal muscle and the specific names for the abdominal muscles and their combination with electromyography, and/or strengthening, and/or exercise, and/or spine stability, and/or low back pain. The related topics included the influence of the different exercises, modification of exercise positions, involvement of different joints, the position with supported or unsupported segments, plane variation to modify loads, and the use of equipment. Studies related to abdominal conditioning exercises and core stabilization were also reviewed. Eighty-seven studies were identified as relevant for this literature synthesis. Overall, the studies retrieved lacked consistency, which made it impossible to extract aggregate estimates and did not allow for a rigorous meta-analysis. The most important factors for the selection of abdominal strengthening exercises are (a) spine flexion and rotation without hip flexion, (b) arm support, (c) lower body segments involvement controlling the correct performance, (d) inclined planes or additional loads to increase the contraction intensity significantly, and (e) when the goal is to challenge spine stability, exercises such as abdominal bracing or abdominal hollowing are preferable depending on the participants' objectives and characteristics. Pertaining to safety criteria, the most important factors are (a) avoid active hip flexion and fixed feet, (b) do not pull with the hands behind the head, and (c) a position of knees and hips flexion during upper body exercises. Further replicable studies are needed to address and clarify the methodological doubts expressed in this

  14. Acoustic, respiratory kinematic and electromyographic effects of vocal training

    Science.gov (United States)

    Mendes, Ana Paula De Brito Garcia

    The longitudinal effects of vocal training on the respiratory, phonatory and articulatory systems were investigated in this study. During four semesters, fourteen voice major students were recorded while speaking and singing. Acoustic, temporal, respiratory kinematic and electromyographic parameters were measured to determine changes in the three systems as a function of vocal training. Acoustic measures of the speaking voice included fundamental frequency, sound pressure level (SPL), percent jitter and shimmer, and harmonic-to-noise ratio. Temporal measures included duration of sentences, diphthongs and the closure durations of stop consonants. Acoustic measures of the singing voice included fundamental frequency and sound pressure level of the phonational range, vibrato pulses per second, vibrato amplitude variation and the presence of the singer's formant. Analysis of the data revealed that vocal training had a significant effect on the singing voice. Fundamental frequency and SPL of the 90% level and 90--10% of the phonational range increased significantly during four semesters of vocal training. Physiological data was collected from four subjects during three semesters of vocal training. Respiratory kinematic measures included lung volume, rib cage and abdominal excursions extracted from spoken sung samples. Descriptive statistics revealed that rib cage and abdominal excursions increased from the 1st to the 2nd semester and decrease from the 2nd to the 3rd semester of vocal training. Electromyographic measures of the pectoralis major, rectus abdominis and external obliques muscles revealed that burst duration means decreased from the 1st to the 2nd semester and increased from the 2nd to the 3rd semester. Peak amplitude means increased from the 1st to the 2nd and decreased from the 2nd to the 3rd semester of vocal training. Chest wall excursions and muscle force generation of the three muscles increased as the demanding level and the length of the phonatory

  15. Mandibular kinematics and masticatory muscles EMG in patients with short lasting TMD of mild-moderate severity.

    Science.gov (United States)

    De Felício, Cláudia Maria; Mapelli, Andrea; Sidequersky, Fernanda Vincia; Tartaglia, Gianluca M; Sforza, Chiarella

    2013-06-01

    Mandibular kinematic and standardized surface electromyography (sEMG) characteristics of masticatory muscles of subjects with short lasting TMD of mild-moderate severity were examined. Volunteers were submitted to clinical examination and questionnaire of severity. Ten subjects with TMD (age 27.3years, SD 7.8) and 10 control subjects without TMD, matched by age, were selected. Mandibular movements were recorded during free maximum mouth opening and closing (O-C) and unilateral, left and right, gum chewing. sEMG of the masseter and temporal muscles was performed during maximum teeth clenching either on cotton rolls or in intercuspal position, and during gum chewing. sEMG indices were obtained. Subjects with TMD, relative to control subjects, had lower relative mandibular rotation at the end of mouth opening, larger mean number of intersection between interincisal O-C paths during mastication and smaller asymmetry between working and balancing side, with participation beyond the expected of the contralateral muscles (Pkinematic parameters and the EMG indices of the static test, although some changes in the mastication were observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. sEMG Sensor Using Polypyrrole-Coated Nonwoven Fabric Sheet for Practical Control of Prosthetic Hand.

    Science.gov (United States)

    Jiang, Yinlai; Togane, Masami; Lu, Baoliang; Yokoi, Hiroshi

    2017-01-01

    One of the greatest challenges of using a myoelectric prosthetic hand in daily life is to conveniently measure stable myoelectric signals. This study proposes a novel surface electromyography (sEMG) sensor using polypyrrole-coated nonwoven fabric sheet as electrodes (PPy electrodes) to allow people with disabilities to control prosthetic limbs. The PPy electrodes are sewn on an elastic band to guarantee close contact with the skin and thus reduce the contact electrical impedance between the electrodes and the skin. The sensor is highly customizable to fit the size and the shape of the stump so that people with disabilities can attach the sensor by themselves. The performance of the proposed sensor was investigated experimentally by comparing measurements of Ag/AgCl electrodes with electrolytic gel and the sEMG from the same muscle fibers. The high correlation coefficient (0.87) between the two types of sensors suggests the effectiveness of the proposed sensor. Another experiment of sEMG pattern recognition to control myoelectric prosthetic hands showed that the PPy electrodes are as effective as Ag/AgCl electrodes for measuring sEMG signals for practical myoelectric control. We also investigated the relation between the myoelectric signals' signal-to-noise ratio and the source impedances by simultaneously measuring the source impedances and the myoelectric signals with a switching circuit. The results showed that differences in both the norm and the phase of the source impedance greatly affect the common mode noise in the signal.

  17. Preliminary Study on Continuous Recognition of Elbow Flexion/Extension Using sEMG Signals for Bilateral Rehabilitation

    Directory of Open Access Journals (Sweden)

    Zhibin Song

    2016-10-01

    Full Text Available Surface electromyography (sEMG signals are closely related to the activation of human muscles and the motion of the human body, which can be used to estimate the dynamics of human limbs in the rehabilitation field. They also have the potential to be used in the application of bilateral rehabilitation, where hemiplegic patients can train their affected limbs following the motion of unaffected limbs via some rehabilitation devices. Traditional methods to process the sEMG focused on motion pattern recognition, namely, discrete patterns, which are not satisfactory for use in bilateral rehabilitation. In order to overcome this problem, in this paper, we built a relationship between sEMG signals and human motion in elbow flexion and extension on the sagittal plane. During the conducted experiments, four participants were required to perform elbow flexion and extension on the sagittal plane smoothly with only an inertia sensor in their hands, where forearm dynamics were not considered. In these circumstances, sEMG signals were weak compared to those with heavy loads or high acceleration. The contrastive experimental results show that continuous motion can also be obtained within an acceptable precision range.

  18. Wireless sEMG System with a Microneedle-Based High-Density Electrode Array on a Flexible Substrate.

    Science.gov (United States)

    Kim, Minjae; Gu, Gangyong; Cha, Kyoung Je; Kim, Dong Sung; Chung, Wan Kyun

    2017-12-30

    Surface electromyography (sEMG) signals reflect muscle contraction and hence, can provide information regarding a user's movement intention. High-density sEMG systems have been proposed to measure muscle activity in small areas and to estimate complex motion using spatial patterns. However, conventional systems based on wet electrodes have several limitations. For example, the electrolyte enclosed in wet electrodes restricts spatial resolution, and these conventional bulky systems limit natural movements. In this paper, a microneedle-based high-density electrode array on a circuit integrated flexible substrate for sEMG is proposed. Microneedles allow for high spatial resolution without requiring conductive substances, and flexible substrates guarantee stable skin-electrode contact. Moreover, a compact signal processing system is integrated with the electrode array. Therefore, sEMG measurements are comfortable to the user and do not interfere with the movement. The system performance was demonstrated by testing its operation and estimating motion using a Gaussian mixture model-based, simplified 2D spatial pattern.

  19. A Discrete-Time Algorithm for Stiffness Extraction from sEMG and Its Application in Antidisturbance Teleoperation

    Directory of Open Access Journals (Sweden)

    Peidong Liang

    2016-01-01

    Full Text Available We have developed a new discrete-time algorithm of stiffness extraction from muscle surface electromyography (sEMG collected from human operator’s arms and have applied it for antidisturbance control in robot teleoperation. The variation of arm stiffness is estimated from sEMG signals and transferred to a telerobot under variable impedance control to imitate human motor control behaviours, particularly for disturbance attenuation. In comparison to the estimation of stiffness from sEMG, the proposed algorithm is able to reduce the nonlinear residual error effect and to enhance robustness and to simplify stiffness calibration. In order to extract a smoothing stiffness enveloping from sEMG signals, two enveloping methods are employed in this paper, namely, fast linear enveloping based on low pass filtering and moving average and amplitude monocomponent and frequency modulating (AM-FM method. Both methods have been incorporated into the proposed stiffness variance estimation algorithm and are extensively tested. The test results show that stiffness variation extraction based on the two methods is sensitive and robust to attenuation disturbance. It could potentially be applied for teleoperation in the presence of hazardous surroundings or human robot physical cooperation scenarios.

  20. Broadband Prosthetic Interfaces: Combining Nerve Transfers and Implantable Multichannel EMG Technology to Decode Spinal Motor Neuron Activity

    Directory of Open Access Journals (Sweden)

    Konstantin D. Bergmeister

    2017-07-01

    Full Text Available Modern robotic hands/upper limbs may replace multiple degrees of freedom of extremity function. However, their intuitive use requires a high number of control signals, which current man-machine interfaces do not provide. Here, we discuss a broadband control interface that combines targeted muscle reinnervation, implantable multichannel electromyographic sensors, and advanced decoding to address the increasing capabilities of modern robotic limbs. With targeted muscle reinnervation, nerves that have lost their targets due to an amputation are surgically transferred to residual stump muscles to increase the number of intuitive prosthetic control signals. This surgery re-establishes a nerve-muscle connection that is used for sensing nerve activity with myoelectric interfaces. Moreover, the nerve transfer determines neurophysiological effects, such as muscular hyper-reinnervation and cortical reafferentation that can be exploited by the myoelectric interface. Modern implantable multichannel EMG sensors provide signals from which it is possible to disentangle the behavior of single motor neurons. Recent studies have shown that the neural drive to muscles can be decoded from these signals and thereby the user's intention can be reliably estimated. By combining these concepts in chronic implants and embedded electronics, we believe that it is in principle possible to establish a broadband man-machine interface, with specific applications in prosthesis control. This perspective illustrates this concept, based on combining advanced surgical techniques with recording hardware and processing algorithms. Here we describe the scientific evidence for this concept, current state of investigations, challenges, and alternative approaches to improve current prosthetic interfaces.

  1. EMG and kinematic analysis of sensorimotor control for patients after stroke using cyclic voluntary movement with visual feedback

    Directory of Open Access Journals (Sweden)

    Song Rong

    2013-02-01

    Full Text Available Abstract Background Clinical scales are often used to evaluate upper-limb deficits. The objective of this study is to investigate the parameters during voluntary arm tracking at different velocities for evaluating motor control performance after stroke. Methods Eight hemiplegic chronic stroke subjects were recruited to perform voluntary movements of elbow flexion and extension by following sinusoidal trajectories from 30 deg to 90 deg at six velocities in the horizontal plane by completing 3, 6, 8, 12, 15, 18 flexion and extension cycles in 36 seconds in a single trial, and the peak velocities ranged from 15.7 to 94.2 deg/s. The actual elbow angle and the target position were displayed as real-time visual feedback. The angular displacement of the arm and electromyographic (EMG signals of biceps and triceps were captured to evaluate the sensorimotor control of the affected and unaffected side. Results The results showed significant differences in the root mean square error (RMSE, response delay (RD and cocontraction index (CI when the affected and unaffected sides were compared during the arm tracking experiment (P Conclusions The method and parameters have potential for clinical use in quantitatively evaluating the sensorimotor deficiencies for patients after stroke about the accuracy of motion, response delay and cocontraction between muscle pairs.

  2. Stationary Wavelet-based Two-directional Two-dimensional Principal Component Analysis for EMG Signal Classification

    Directory of Open Access Journals (Sweden)

    Ji Yi

    2017-06-01

    Full Text Available Discrete wavelet transform (WT followed by principal component analysis (PCA has been a powerful approach for the analysis of biomedical signals. Wavelet coefficients at various scales and channels were usually transformed into a one-dimensional array, causing issues such as the curse of dimensionality dilemma and small sample size problem. In addition, lack of time-shift invariance of WT coefficients can be modeled as noise and degrades the classifier performance. In this study, we present a stationary wavelet-based two-directional two-dimensional principal component analysis (SW2D2PCA method for the efficient and effective extraction of essential feature information from signals. Time-invariant multi-scale matrices are constructed in the first step. The two-directional two-dimensional principal component analysis then operates on the multi-scale matrices to reduce the dimension, rather than vectors in conventional PCA. Results are presented from an experiment to classify eight hand motions using 4-channel electromyographic (EMG signals recorded in healthy subjects and amputees, which illustrates the efficiency and effectiveness of the proposed method for biomedical signal analysis.

  3. Influence of aging on isometric muscle strength, fat-free mass and electromyographic signal power of the upper and lower limbs in women.

    Science.gov (United States)

    Amaral, Josária F; Alvim, Felipe C; Castro, Eliane A; Doimo, Leonice A; Silva, Marcus V; Novo Júnior, José M

    2014-01-01

    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. 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. 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. 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 pstrength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb.

  4. Surface Electromyography for Speech and Swallowing Systems: Measurement, Analysis, and Interpretation

    Science.gov (United States)

    Stepp, Cara E.

    2012-01-01

    Purpose: Applying surface electromyography (sEMG) to the study of voice, speech, and swallowing is becoming increasingly popular. An improved understanding of sEMG and building a consensus as to appropriate methodology will improve future research and clinical applications. Method: An updated review of the theory behind recording sEMG for the…

  5. Intramuscular pressure and EMG relate during static contractions but dissociate with movement and fatigue

    DEFF Research Database (Denmark)

    Sjøgaard, Gisela; Jensen, Bente R.; Hargens, Allan R.

    2004-01-01

    Intramuscular pressure (IMP) and electromyography (EMG) mirror muscle force in the nonfatigued muscle during static contractions. The present study explores whether the constant IMP-EMG relationship with increased force may be extended to dynamic contractions and to fatigued muscle. IMP and EMG...... with speed of abduction. In the nonfatigued supraspinatus muscle, a linear relationship was found between IMP and EMG; in contrast, during fatigue and recovery, significant timewise changes of the IMP-to-EMG ratio occurred. The results indicate that IMP should be included along with EMG when mechanical load...... sharing between muscles is evaluated during dynamic and fatiguing contractions....

  6. Geometric and electromyographic assessments in the evaluation of curve progression in idiopathic scoliosis

    NARCIS (Netherlands)

    Cheung, J; Veldhuizen, AG; Halberts, JPK; Sluiter, WJ; Van Horn, [No Value

    2006-01-01

    Study Design. The natural history of patients with idiopathic scoliosis was analyzed radiographically and electromyographically in a prospective longitudinal study. Objectives. To identify changes in geometric variables and the sequence in which these changes occur during curve progression in the

  7. A critical period of corticomuscular and EMG-EMG coherence detection in healthy infants aged 9-25weeks

    DEFF Research Database (Denmark)

    Ritterband-Rosenbaum, Anina; Herskind, Anna; Li, Xi

    2017-01-01

    The early postnatal development of functional corticospinal connections in human infants is not fully clarified. We used EEG and EMG to investigate the development of corticomuscular and intramuscular coherence as indicators of functional corticospinal connectivity in healthy infants aged 1...... for infants younger than 9 weeks, whereas a short-lasting (10-20 ms) central peak was observed for EMG-EMG synchronization in older infants. This peak was largest for infants aged 9-25 weeks. These data suggest that the corticospinal drive to lower and upper limb muscles shows significant developmental...... changes with an increase in functional coupling in infants aged 9-25 weeks, a period which coincides partly with the developmental period of normal fidgety movements. We propose that these neurophysiological findings may reflect the existence of a sensitive period where the functional connections between...

  8. Muscle fatigue in women with primary biliary cirrhosis: Spectral analysis of surface electromyography

    Science.gov (United States)

    Biagini, Maria Rosa; Tozzi, Alessandro; Grippo, Antonello; Galli, Andrea; Milani, Stefano; Amantini, Aldo

    2006-01-01

    AIM: To evaluate the myoelectric manifestations of peripheral fatigability in patients with primary biliary cirrhosis in comparison to healthy subjects. METHODS: Sixteen women with primary biliary cirrhosis without comorbidity and 13 healthy women matched for age and body mass index (BMI) completed the self-reported questionnaire fatigue impact scale. All subjects underwent surface electromyography assessment of peripheral fatigability. Anterior tibial muscle isometric voluntary contraction was executed for 20 s at 80% of maximal voluntary isometric contraction. During the exercise electromyographic signal series were recorded and root mean square (expression of central drive) as well as mean and median of electromyographic signal frequency spectrum (estimates of muscle fatigability) were computed. Each subject executed the trial two times. EMG parameters were normalized, then linear regression was applied and slopes were calculated. RESULTS: Seven patients were fatigued (median fatigue impact scale score: 38, range: 26-66) and 9 were not fatigued (median fatigue impact scale score: 7, range: 0-17). The maximal voluntary isometric contraction was similar in patients (82, 54-115 N) and controls (87, 74-101 N), and in patients with high (81, 54-115 N) and low fatigue impact scale scores (86, 65-106 N). Root mean square as well as mean and median of frequency spectrum slopes were compared with the Mann-Whitney U test, and no significant difference was found between fatigued and non-fatigued patients and controls. CONCLUSION: No instrumental evidence of peripheral fatigability can be found in women with primary biliary cirrhosis but no comorbidity, suggesting that fatigue in such patients may be of central origin. PMID:16937530

  9. EMG-based detection of muscle fatigue during low-level isometric contraction by recurrence quantification analysis and monopolar configuration.

    Science.gov (United States)

    Ito, Kenichi; Hotta, Yu

    2012-01-01

    The center frequency (CF) of the power spectral density of a bipolar-configured surface electromyogram is typically used as an index of muscle fatigue. However, this index may be inadequate for measuring wave slowing due to muscle fatigue during low-level contractions. A previous study in which strong muscle fatigue was mimicked by compressing the proximal region of the forearm during isometric contractions showed that the differences in the degree of fatigue under compression and non-compression conditions were undetectable. The purpose of this study was to improve detection sensitivity of surface EMG variation caused by muscle fatigue using two approaches. The first approach employed recurrence quantification analysis (RQA) instead of traditional frequency analysis (FA) to compute the muscle fatigue index. The second approach employed a monopolar configuration for measuring surface EMG. We measured the surface EMG signal by using monopolar and bipolar configurations simultaneously during low-level isometric contractions under blood flow-restricted (BFR) and unrestricted (CON) conditions, and then compared and evaluated the detected differences in muscle fatigue. The results showed that the effect of BFR was better detected by RQA than by FA, and that the fatigability change was larger in the monopolar configuration than in the bipolar configuration.

  10. The EMG activity-acceleration relationship to quantify the optimal vibration load when applying synchronous whole-body vibration.

    Science.gov (United States)

    Di Giminiani, Riccardo; Masedu, Francesco; Padulo, Johnny; Tihanyi, Jozsef; Valenti, Marco

    2015-12-01

    To date are lacking methodological approaches to individualizing whole-body vibration (WBV) intensity. The aim of this study was: (1) to determine the surface-electromyography-root-mean-square (sEMG(RMS))-acceleration load relationship in the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), lateral gastrocnemius (LG) muscles during synchronous WBV, and (2) to assess the reliability of the acceleration corresponding to the maximal sEMG(RMS). Twenty-five sportsman voluntarily took part in this study with a single-group, repeated-measures design. All subjects postured themselves in an isometric half-squat during nine trials in the following conditions: no vibrations and random vibrations of different acceleration loads (from 0.12 to 5.72 g). The sEMG(RMS) were dependent on the acceleration loads in the VL (p = 0.0001), LG (p = 0.0001) and VM (p = 0.011) muscles; while RF was not affected by the acceleration loads (p = 0.508). The comparisons among the sEMG(RMS)-accelerations relationships revealed a significant difference between the LG and the others muscles (p = 0.001). No significant difference was found between the different thigh muscles (p > 0.05). The intra-class correlation coefficient ranged from 0.87 to 0.99 for the measurements performed on the LG, VL and VM. The sEMG(RMS)-acceleration relationship in the VL, VM and LG is a reliable test to individualize the WBV intervention. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Analysis of EMG Signals in Aggressive and Normal Activities by Using Higher-Order Spectra

    Science.gov (United States)

    Sezgin, Necmettin

    2012-01-01

    The analysis and classification of electromyography (EMG) signals are very important in order to detect some symptoms of diseases, prosthetic arm/leg control, and so on. In this study, an EMG signal was analyzed using bispectrum, which belongs to a family of higher-order spectra. An EMG signal is the electrical potential difference of muscle cells. The EMG signals used in the present study are aggressive or normal actions. The EMG dataset was obtained from the machine learning repository. First, the aggressive and normal EMG activities were analyzed using bispectrum and the quadratic phase coupling of each EMG episode was determined. Next, the features of the analyzed EMG signals were fed into learning machines to separate the aggressive and normal actions. The best classification result was 99.75%, which is sufficient to significantly classify the aggressive and normal actions. PMID:23193379

  12. Analysis of EMG Signals in Aggressive and Normal Activities by Using Higher-Order Spectra

    Directory of Open Access Journals (Sweden)

    Necmettin Sezgin

    2012-01-01

    Full Text Available The analysis and classification of electromyography (EMG signals are very important in order to detect some symptoms of diseases, prosthetic arm/leg control, and so on. In this study, an EMG signal was analyzed using bispectrum, which belongs to a family of higher-order spectra. An EMG signal is the electrical potential difference of muscle cells. The EMG signals used in the present study are aggressive or normal actions. The EMG dataset was obtained from the machine learning repository. First, the aggressive and normal EMG activities were analyzed using bispectrum and the quadratic phase coupling of each EMG episode was determined. Next, the features of the analyzed EMG signals were fed into learning machines to separate the aggressive and normal actions. The best classification result was 99.75%, which is sufficient to significantly classify the aggressive and normal actions.

  13. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Objective. Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. Approach. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. Main Results. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Significance. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle

  14. Open-Box Muscle-Computer Interface: Introduction to Human-Computer Interactions in Bioengineering, Physiology, and Neuroscience Courses

    Science.gov (United States)

    Landa-Jiménez, M. A.; González-Gaspar, P.; Pérez-Estudillo, C.; López-Meraz, M. L.; Morgado-Valle, C.; Beltran-Parrazal, L.

    2016-01-01

    A Muscle-Computer Interface (muCI) is a human-machine system that uses electromyographic (EMG) signals to communicate with a computer. Surface EMG (sEMG) signals are currently used to command robotic devices, such as robotic arms and hands, and mobile robots, such as wheelchairs. These signals reflect the motor intention of a user before the…

  15. Does EMG activation differ among fatigue-resistant leg muscles ...

    African Journals Online (AJOL)

    The participants (N=32) were divided into two groups according to the Fatigue Index value [Group I: Less Fatigue Resistant (LFR), n=17; Group II: More Fatigue Resistant (MFR), n=15]. The repeated EMG activities of four leg muscles [rectus femoris, biceps femoris, vastus lateralis and vastus medialis] were analysed during ...

  16. EMG Processing Based Measures of Fatigue Assessment during Manual Lifting

    Directory of Open Access Journals (Sweden)

    E. F. Shair

    2017-01-01

    Full Text Available Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs, where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG signal is used to monitor the workers’ muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird’s eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

  17. EMG Processing Based Measures of Fatigue Assessment during Manual Lifting

    Science.gov (United States)

    Marhaban, M. H.; Abdullah, A. R.

    2017-01-01

    Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications. PMID:28303251

  18. Trapezius muscle EMG as predictor of mental stress

    NARCIS (Netherlands)

    Wijsman, J.L.P; Grundlehner, B.; Penders, J.; Hermens, Hermanus J.

    Stress is a growing problem in society and can cause musculoskeletal complaints. It would be useful to measure stress for prevention of stress-related health problems. An experiment is described in which EMG signals of the upper trapezius muscle were measured with a wireless system during three

  19. Effects of load on good morning kinematics and EMG activity

    Directory of Open Access Journals (Sweden)

    Andrew David Vigotsky

    2015-01-01

    Full Text Available Many strength and conditioning coaches utilize the good morning (GM to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  20. 3D-printing soft sEMG sensing structures

    NARCIS (Netherlands)

    Wolterink, Gerjan; Sanders, Remco; Muijzer, Frodo; van Beijnum, Bert-Jan; Krijnen, Gijs

    2017-01-01

    This paper describes the development and characterization of soft and flexible 3D-printed sEMG electrodes. The electrodes are printed in one go on a low cost consumer multi-material FDM printer. The printed structures do not need any further production steps to give them conductive properties.

  1. EMG Processing Based Measures of Fatigue Assessment during Manual Lifting.

    Science.gov (United States)

    Shair, E F; Ahmad, S A; Marhaban, M H; Mohd Tamrin, S B; Abdullah, A R

    2017-01-01

    Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

  2. EMG based FES for post-stroke rehabilitation

    Science.gov (United States)

    Piyus, Ceethal K.; Anjaly Cherian, V.; Nageswaran, Sharmila

    2017-11-01

    Annually, 15 million in world population experiences stroke. Nearly 9 million stroke survivors every year experience mild to severe disability. The loss of upper extremity function in stroke survivors still remains a major rehabilitation challenge. The proposed EMG Abstract—Annually, 15 million in world population experiences stroke. Nearly 9 million stroke survivors every year experience mild to severe disability. The loss of upper extremity function in stroke survivors still remains a major rehabilitation challenge. The proposed EMG based FES system can be used for effective upper limb motor re-education in post stroke upper limb rehabilitation. The governing feature of the designed system is its synchronous activation, in which the FES stimulation is dependent on the amplitude of the EMG signal acquired from the unaffected upper limb muscle of the hemiplegic patient. This proportionate operation eliminates the undesirable damage to the patient’s skin by generating stimulus in proportion to voluntary EMG signals. This feature overcomes the disadvantages of currently available manual motor re-education systems. This model can be used in home-based post stroke rehabilitation, to effectively improve the upper limb functions.

  3. EMG-based simultaneous and proportional estimation of wrist/hand kinematics in uni-lateral trans-radial amputees

    Science.gov (United States)

    2012-01-01

    We propose a method for estimating wrist kinematics during dynamic wrist contractions from multi-channel surface electromyography (EMG). The algorithm extracts features from the surface EMG and uses dedicated multi-layer perceptron networks to estimate individual joint angles of the 3 degrees of freedom (DoFs) of the wrist. The method was designed with the aim of proportional and simultaneous control of multiple DoFs of active prostheses by unilateral amputees. Therefore, the proposed approach was tested in both unilateral transradial amputees and in intact-limbed control subjects. It was shown that the joint angles at the 3 DoFs of amputees can be estimated from surface EMG recordings , during mirrored bi-lateral contractions that simultaneously and proportionally articulated the 3 DoFs. The estimation accuracies of amputee subjects with long stumps were 62.5% ± 8.50% across all 3 DoFs, while accuracies of the intact-limbed control subjects were 72.0% ± 8.29%. The estimation results from intact-limbed subjects were consistent with earlier studies. The results from the current study demonstrated the feasibility of the proposed myoelectric control approach to provide a more intuitive myoelectric control strategy for unilateral transradial amputees. PMID:22742707

  4. EMG-based simultaneous and proportional estimation of wrist/hand kinematics in uni-lateral trans-radial amputees

    Directory of Open Access Journals (Sweden)

    Jiang Ning

    2012-06-01

    Full Text Available Abstract We propose a method for estimating wrist kinematics during dynamic wrist contractions from multi-channel surface electromyography (EMG. The algorithm extracts features from the surface EMG and uses dedicated multi-layer perceptron networks to estimate individual joint angles of the 3 degrees of freedom (DoFs of the wrist. The method was designed with the aim of proportional and simultaneous control of multiple DoFs of active prostheses by unilateral amputees. Therefore, the proposed approach was tested in both unilateral transradial amputees and in intact-limbed control subjects. It was shown that the joint angles at the 3 DoFs of amputees can be estimated from surface EMG recordings , during mirrored bi-lateral contractions that simultaneously and proportionally articulated the 3 DoFs. The estimation accuracies of amputee subjects with long stumps were 62.5% ± 8.50% across all 3 DoFs, while accuracies of the intact-limbed control subjects were 72.0% ± 8.29%. The estimation results from intact-limbed subjects were consistent with earlier studies. The results from the current study demonstrated the feasibility of the proposed myoelectric control approach to provide a more intuitive myoelectric control strategy for unilateral transradial amputees.

  5. Stretchable human-machine interface based on skin-conformal sEMG electrodes with self-similar geometry

    Science.gov (United States)

    Dong, Wentao; Zhu, Chen; Hu, Wei; Xiao, Lin; Huang, Yong'an

    2018-01-01

    Current stretchable surface electrodes have attracted increasing attention owing to their potential applications in biological signal monitoring, wearable human-machine interfaces (HMIs) and the Internet of Things. The paper proposed a stretchable HMI based on a surface electromyography (sEMG) electrode with a self-similar serpentine configuration. The sEMG electrode was transfer-printed onto the skin surface conformally to monitor biological signals, followed by signal classification and controlling of a mobile robot. Such electrodes can bear rather large deformation (such as >30%) under an appropriate areal coverage. The sEMG electrodes have been used to record electrophysiological signals from different parts of the body with sharp curvature, such as the index finger, back of the neck and face, and they exhibit great potential for HMI in the fields of robotics and healthcare. The electrodes placed onto the two wrists would generate two different signals with the fist clenched and loosened. It is classified to four kinds of signals with a combination of the gestures from the two wrists, that is, four control modes. Experiments demonstrated that the electrodes were successfully used as an HMI to control the motion of a mobile robot remotely. Project supported by the National Natural Science Foundation of China (Nos. 51635007, 91323303).

  6. A Versatile Embedded Platform for EMG Acquisition and Gesture Recognition.

    Science.gov (United States)

    Benatti, Simone; Casamassima, Filippo; Milosevic, Bojan; Farella, Elisabetta; Schönle, Philipp; Fateh, Schekeb; Burger, Thomas; Huang, Qiuting; Benini, Luca

    2015-10-01

    Wearable devices offer interesting features, such as low cost and user friendliness, but their use for medical applications is an open research topic, given the limited hardware resources they provide. In this paper, we present an embedded solution for real-time EMG-based hand gesture recognition. The work focuses on the multi-level design of the system, integrating the hardware and software components to develop a wearable device capable of acquiring and processing EMG signals for real-time gesture recognition. The system combines the accuracy of a custom analog front end with the flexibility of a low power and high performance microcontroller for on-board processing. Our system achieves the same accuracy of high-end and more expensive active EMG sensors used in applications with strict requirements on signal quality. At the same time, due to its flexible configuration, it can be compared to the few wearable platforms designed for EMG gesture recognition available on market. We demonstrate that we reach similar or better performance while embedding the gesture recognition on board, with the benefit of cost reduction. To validate this approach, we collected a dataset of 7 gestures from 4 users, which were used to evaluate the impact of the number of EMG channels, the number of recognized gestures and the data rate on the recognition accuracy and on the computational demand of the classifier. As a result, we implemented a SVM recognition algorithm capable of real-time performance on the proposed wearable platform, achieving a classification rate of 90%, which is aligned with the state-of-the-art off-line results and a 29.7 mW power consumption, guaranteeing 44 hours of continuous operation with a 400 mAh battery.

  7. A novel method for EMG decomposition based on matched filters

    Directory of Open Access Journals (Sweden)

    Ailton Luiz Dias Siqueira Júnior

    Full Text Available Introduction Decomposition of electromyography (EMG signals into the constituent motor unit action potentials (MUAPs can allow for deeper insights into the underlying processes associated with the neuromuscular system. The vast majority of the methods for EMG decomposition found in the literature depend on complex algorithms and specific instrumentation. As an attempt to contribute to solving these issues, we propose a method based on a bank of matched filters for the decomposition of EMG signals. Methods Four main units comprise our method: a bank of matched filters, a peak detector, a motor unit classifier and an overlapping resolution module. The system’s performance was evaluated with simulated and real EMG data. Classification accuracy was measured by comparing the responses of the system with known data from the simulator and with the annotations of a human expert. Results The results show that decomposition of non-overlapping MUAPs can be achieved with up to 99% accuracy for signals with up to 10 active motor units and a signal-to-noise ratio (SNR of 10 dB. For overlapping MUAPs with up to 10 motor units per signal and a SNR of 20 dB, the technique allows for correct classification of approximately 71% of the MUAPs. The method is capable of processing, decomposing and classifying a 50 ms window of data in less than 5 ms using a standard desktop computer. Conclusion This article contributes to the ongoing research on EMG decomposition by describing a novel technique capable of delivering high rates of success by means of a fast algorithm, suggesting its possible use in future real-time embedded applications, such as myoelectric prostheses control and biofeedback systems.

  8. Electromyographic assessment of trunk and shoulder muscles during a Pilates pull-up exercise

    Directory of Open Access Journals (Sweden)

    Isabel C.N. Sacco

    2014-06-01

    Full Text Available This study compares surface electromyographic activity of the internal oblique, rectus abdominis, multifidus, iliocostalis, anterior deltoids during the pull-up on a lower and on a higher difficulty level. We assessed nine adults with previous experience in Pilates. The root mean square (RMS values were normalized by maximum isometric contraction for each participant. During the ascent phase, the low spring position showed a significantly higher RMS than the high spring position of 8.9% for deltoid, 17.2% for internal oblique, 22.3% for rectus abdominis, 4.1% for iliocostalis, and 5.6% for multifidus, and in the descent phase, the RMS in the lower spring exceeded significantly the high spring position in 1.6% for the deltoid, 10% for internal oblique, 31.4% for rectus abdominis and 11.4% for iliocostalis. There was no predominance of abdominal muscles over the shoulder muscle in any spring position. The pull-up exercise can be a useful choice for the core and anterior deltoid muscles strengthening.

  9. Electromyographic study of rotator cuff muscle activity during full and empty can tests

    Directory of Open Access Journals (Sweden)

    Yoshihiro Kai

    2015-01-01

    Full Text Available The empty can (EC and full can (FC tests are used as diagnostic tools for patients with rotator cuff disease. However, recently concerns have been raised that these tests do not selectively activate the muscle. Therefore, the purpose of this study was to evaluate the rotator cuff muscle activation levels during the EC and FC tests in various positions using electromyography. Twelve healthy, right-handed men without shoulder complaints (mean age: 26.1 years, range: 23–35 years were included. The tests were performed isometrically with the shoulder elevated at 45° and 90° in the sagittal, scapular, and coronal planes, either in the thumb-up (FC test or thumb-down (EC test positions. During these positions, the electromyographic signal was recorded simultaneously from the four shoulder muscles using a combination of surface and intramuscular fine-wire electrodes. The average activation of the supraspinatus and subscapularis was greater during the EC test than during the FC test and in the scapular and coronal planes than in the sagittal plane at 90°. For the infraspinatus, there were no significant differences in any positions between the two tests. Thus, the rotator cuff muscles are influenced by arm position and the elevation plane during the EC and FC tests.

  10. Trunk muscle electromyographic activity with unstable and unilateral exercises.

    Science.gov (United States)

    Behm, David G; Leonard, Allison M; Young, Warren B; Bonsey, W Andrew C; MacKinnon, Scott N

    2005-02-01

    The purpose of this cross-sectional study was to evaluate the effect of unstable and unilateral resistance exercises on trunk muscle activation. Eleven subjects (6 men and 5 women) between 20 and 45 years of age participated. Six trunk exercises, as well as unilateral and bilateral shoulder and chest presses against resistance, were performed on stable (bench) and unstable (Swiss ball) bases. Electromyographic activity of the upper lumbar, lumbosacral erector spinae, and lower-abdominal muscles were monitored. Instability generated greater activation of the lower-abdominal stabilizer musculature (27.9%) with the trunk exercises and all trunk stabilizers (37.7-54.3%) with the chest press. There was no effect of instability on the shoulder press. Unilateral shoulder press produced greater activation of the back stabilizers, and unilateral chest press resulted in higher activation of all trunk stabilizers, when compared with bilateral presses. Regardless of stability, the superman exercise was the most effective trunk-stabilizer exercise for back-stabilizer activation, whereas the side bridge was the optimal exercise for lower-abdominal muscle activation. Thus, the most effective means for trunk strengthening should involve back or abdominal exercises with unstable bases. Furthermore, trunk strengthening can also occur when performing resistance exercises for the limbs, if the exercises are performed unilaterally.

  11. Electromyographic activity of beating and reaching during simulated boardsailing.

    Science.gov (United States)

    Buchanan, M; Cunningham, P; Dyson, R J; Hurrion, P D

    1996-04-01

    This study examined the responses of six competitive boardsailors (three males, three females) during laboratory-based simulation tasks while the electromyographic activity of up to 13 muscles was recorded. A sailboard, mounted in a steel frame and resting on a waterbed, allowed simulation of roll and pitch movements. Wind force was simulated by attaching the boom to a weight stack with a hydraulically controlled buffered release phase. The progression of the simulation test was controlled by the sailor copying movements on an edited video of each subject boardsailing on the open water. Analysis of individual pumping movements for mean peak percentage of maximal enveloped voluntary contraction (%MEVC) in 'beating' and 'reaching' showed that muscular activity in the arm (flexor carpi ulnaris, extensor carpi radialis and biceps brachii) was greatest (66-94% MEVC), with considerable activity (58-75% MEVC) in the deltoid and trapezius shoulder muscles, but much less activity in the leg muscles (16-40% MEVC). For the combined upper and lower body muscles there was a significant difference (P reflecting the current dynamic nature of the sport.

  12. Reflex-mediated dynamic neuromuscular stabilization in stroke patients: EMG processing and ultrasound imaging.

    Science.gov (United States)

    Yoon, Hyun S; You, Joshua Sung H

    2017-07-20

    Postural core instability is associated with poor dynamic balance and a high risk of serious falls. Both neurodevelopmental treatment (NDT) and dynamic neuromuscular stabilization (DNS) core stabilization exercises have been used to improve core stability, but the outcomes of these treatments remain unclear. This study was undertaken to examine the therapeutic effects of NDT and DNS core stabilization exercises on muscular activity, core stability, and core muscle thickness. Ten participants (5 healthy adults; 5 hemiparetic stroke patients) were recruited. Surface electromyography (EMG) was used to determine core muscle activity of the transversus abdominis/internal oblique (TrA/IO), external oblique (EO), and rectus abdominis (RA) muscles. Ultrasound imaging was used to measure transversus abdominals/internal oblique (TrA/IO) thickness, and a pressure biofeedback unit (PBU) was used to measure core stability during the DNS and NDT core exercise conditions. Data are reported as median and range and were compared using nonparametric Mann - Whitney U test and Wilcoxon signed rank test at p< 0.05. Both healthy and hemiparetic stroke groups showed greater median EMG amplitude in the TrA/IO muscles, core stability, and muscle thickness values during the DNS exercise condition than during the NDT core exercise condition, respectively (p< 0.05). However, the relative changes in the EMG amplitude, core stability, and muscle thickness values were greater during the DNS exercise condition than during the NDT core exercise condition in the hemiparetic stroke patient group (p< 0.05). Our novel results provide the first clinical evidence that DNS is more effective than NDT in both healthy and hemiparetic stroke subjects to provide superior deep core muscle activation, core stabilization, and muscle thickness. Moreover, such advantageous therapeutic benefits of the DNS core stabilization exercise over the NDT exercise were more apparent in the hemiparetis stroke patients than

  13. Slow-time changes in human EMG muscle fatigue states are fully represented in movement kinematics.

    Science.gov (United States)

    Song, Miao; Segala, David B; Dingwell, Jonathan B; Chelidze, David

    2009-02-01

    The ability to identify physiologic fatigue and related changes in kinematics can provide an important tool for diagnosing fatigue-related injuries. This study examined an exhaustive cycling task to demonstrate how changes in movement kinematics and variability reflect underlying changes in local muscle states. Motion kinematics data were used to construct fatigue features. Their multivariate analysis, based on smooth orthogonal decomposition, was used to reconstruct physiological fatigue. Two different features composed of (1) standard statistical metrics (SSM), which were a collection of standard long-time measures, and (2) phase space warping (PSW)-based metrics, which characterized short-time variations in the phase space trajectories, were considered. Movement kinematics and surface electromyography (EMG) signals were measured from the lower extremities of seven highly trained cyclists as they cycled to voluntary exhaustion on a stationary bicycle. Mean and median frequencies from the EMG time series were computed to measure the local fatigue dynamics of individual muscles independent of the SSM- and PSW-based features, which were extracted solely from the kinematics data. A nonlinear analysis of kinematic features was shown to be essential for capturing full multidimensional fatigue dynamics. A four-dimensional fatigue manifold identified using a nonlinear PSW-based analysis of kinematics data was shown to adequately predict all EMG-based individual muscle fatigue trends. While SSM-based analyses showed similar dominant global fatigue trends, they failed to capture individual muscle activities in a low-dimensional manifold. Therefore, the nonlinear PSW-based analysis of strictly kinematic time series data directly predicted all of the local muscle fatigue trends in a low-dimensional systemic fatigue trajectory. These results provide the first direct quantitative link between changes in muscle fatigue dynamics and resulting changes in movement kinematics.

  14. Electromyographic evaluation of high-intensity elastic resistance exercises for lower extremity muscles during bed rest

    DEFF Research Database (Denmark)

    Vinstrup, Jonas; Skals, Sebastian; Calatayud, Joaquin

    2017-01-01

    extremity muscles and normalized to the maximal EMG (nEMG). Likewise, exercise satisfaction was evaluated by a questionnaire. RESULTS: All participants were able to perform all exercises without discomfort and generally rated them satisfactory. High levels of muscle activity were observed for all prime...

  15. Towards the control of an active hand orthosis for people with Duchenne muscular dystrophy : Design and Validation of a wireless sEMG sleeve

    NARCIS (Netherlands)

    Nizamis, Kostas; Ganseij, Maarten; Koopman, H.F.J.M.

    2017-01-01

    Duchenne Muscular Dystrophy (DMD) is a progressive muscular disease. Active hand orthoses can greatly improve the quality of life of people with DMD. Surface Electromyography (sEMG) is commonly used for the control of active devices. The interfacing between the human and the sensor is regularly done

  16. Comparison of gluteus maximus and hamstring electromyographic activity and lumbopelvic motion during three different prone hip extension exercises in healthy volunteers.

    Science.gov (United States)

    Jeon, In-Cheol; Hwang, Ui-Jae; Jung, Sung-Hoon; Kwon, Oh-Yun

    2016-11-01

    To compare the surface electromyography (EMG) amplitude of the hip joint, including the gluteus maximus (GM), biceps femoris (BF), and semitendinosus (ST) muscles generated by three different exercises: prone hip extension (PHE), prone table hip extension (PTHE), and prone table hip extension with 90° knee flexion (PTHEK), with compensatory pelvic motions. Repeated-measure within-subject intervention. Sixteen-healthy males (mean age = 23.4 ± 2.2 years). EMG was used to collect EMG signals from the GM, erector spinae (ES), BF, and ST muscles. Furthermore an electromagnetic tracking motion analysis was also performed to measure the compensations. EMG amplitude differed significantly among the three conditions (PHE vs. PTHE vs. PTHEK) (p  0.05). These results suggest that the PTHEK can be recommended as an effective method to strengthen the GM muscle without increased BF or ES muscle activities and without compensatory pelvic motions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The effect of different skin-ankle brace application pressures on quiet single-limb balance and electromyographic activation onset of lower limb muscles.

    Science.gov (United States)

    Papadopoulos, Emmanuel S; Nikolopoulos, Christos; Badekas, Athanasios; Vagenas, George; Papadakis, Stamatios A; Athanasopoulos, Spyros

    2007-09-12

    Several studies have been carried out in order to investigate the effect of ankle bracing on ankle joint function and performance. However, no study so far has examined the role of skin-brace interface pressure in neuromuscular control. The aim of this study was to investigate the effect of different skin-ankle brace interface pressures on quiet single limb balance and the electromyographic (EMG) activation sequence of four lower limb muscles. Thirty three male physical education students who volunteered to take part in the study were measured under three ankle brace conditions: i) without brace, ii) with brace and 30 kPa application pressure and iii) with brace and 60 kPa application pressure. Single limb balance (anteroposterior and mediolateral parameter) was assessed on the dominant lower limb, with open and closed eyes, on a force platform, simultaneously with the EMG recording of four lower lower limb muscles' (gastrocnemius, peroneus longus, rectus femoris and biceps femoris) activation onset. The results showed that overall balance (total stability parameter) was not significantly affected in any of the three ankle brace conditions. However, the anteroposterior centre of pressure excursion and centre of pressure excursion velocity were significantly increased with the application of ankle brace, both with 30 and 60 kPa application pressures. Furthermore, it was found that single limb balance was significantly worse with closed eyes compared to open eyes. EMG measurements showed that the sequence of lower limb activation onset was not affected in any of the three ankle brace application conditions. The results of this study showed that the application of an ankle brace with two different skin-brace interface pressures had no effect on overall single limb balance and the sequence of lower limb muscle activation. These findings suggest that peripheral joint receptors are either not adequately stimulated by the brace application and therefore are not able to

  18. The effect of different skin-ankle brace application pressures on quiet single-limb balance and electromyographic activation onset of lower limb muscles

    Directory of Open Access Journals (Sweden)

    Papadakis Stamatios A

    2007-09-01

    Full Text Available Abstract Background Several studies have been carried out in order to investigate the effect of ankle bracing on ankle joint function and performance. However, no study so far has examined the role of skin-brace interface pressure in neuromuscular control. The aim of this study was to investigate the effect of different skin-ankle brace interface pressures on quiet single limb balance and the electromyographic (EMG activation sequence of four lower limb muscles. Methods Thirty three male physical education students who volunteered to take part in the study were measured under three ankle brace conditions: i without brace, ii with brace and 30 kPa application pressure and iii with brace and 60 kPa application pressure. Single limb balance (anteroposterior and mediolateral parameter was assessed on the dominant lower limb, with open and closed eyes, on a force platform, simultaneously with the EMG recording of four lower lower limb muscles' (gastrocnemius, peroneus longus, rectus femoris and biceps femoris activation onset. Results The results showed that overall balance (total stability parameter was not significantly affected in any of the three ankle brace conditions. However, the anteroposterior centre of pressure excursion and centre of pressure excursion velocity were significantly increased with the application of ankle brace, both with 30 and 60 kPa application pressures. Furthermore, it was found that single limb balance was significantly worse with closed eyes compared to open eyes. EMG measurements showed that the sequence of lower limb activation onset was not affected in any of the three ankle brace application conditions. The results of this study showed that the application of an ankle brace with two different skin-brace interface pressures had no effect on overall single limb balance and the sequence of lower limb muscle activation. Conclusion These findings suggest that peripheral joint receptors are either not adequately

  19. Avaliação eletromiográfica dos músculos estabilizadores da patela durante exercício isométrico de agachamento em indivíduos com síndrome da dor femoropatelar Evaluacion eletromiográfica de los músculos estabilizadores patelares durante el ejercício isométrico de agachamiento en indivíduos con síndrome de dolor femoropatelar Electromyographic activity evaluation of the patella muscles during squat isometric exercise in individuals with patellofemoral pain syndrome

    Directory of Open Access Journals (Sweden)

    Débora Bevilaqua-Grossi

    2005-06-01

    Full Text Available O objetivo deste trabalho foi comparar a atividade elétrica dos músculos vasto medial oblíquo (VMO, vasto lateral longo (VLL e vasto lateral oblíquo (VLO durante os exercícios isométricos de agachamento wall slide a 45º (WS 45º e 60º (WS 60º de flexão do joelho. Foram avaliadas 15 mulheres clinicamente saudáveis e 15 mulheres com síndrome da dor femoropatelar (SDFP. Os registros eletromiográficos foram obtidos por eletrodos ativos simples conectados a um eletromiógrafo durante a contração isométrica voluntária máxima (CIVM do WS 45º e WS 60º. Os dados foram analisados pela média dos valores do root mean square (RMS do sinal eletromiográfico, normalizado pela média do RMS obtido no agachamento a 75º de flexão do joelho. A análise estatística empregada foi o teste ANOVA two way (p El objetivo de este trabajo fué el de comparar la actvividad eléctrica de los músculos vasto medial oblíqüo (VMO, vasto lateral longo (VLL y vasto lateral oblicuo (VLO durante los ejercicios isometricos de agachamiento wall slide a 45º (WS 45º e 60º (WS 60º de flexión de rodilla. Fueron evaluadas 15 mujeres clinicamente saludables con sindrome de dolor femoropatelar (SDFP. Los registros fueron obtenidos por electrodos activos simples conectados a un electromiografo durante la contraccion isometrica voluntaria máxima (CIVM de WS 45º y de WS 60º. Los datos fueron analizados por la media de los valores de Root Mean Square - RMS de señal eletromiográfica, normalizada por la media del RMS obtenido en el agachamiento a 75º de flexión de la rodilla. El análisis estatístico empleado fue el test ANOVA two way (p The objective of this study was to compare the electromyographic (EMG activity of vastus medialis obliquus (VMO, vastus lateralis longus (VLL and vastus lateralis oblíquus (VLO during wall slide squat isometric exercises at 45º (WS 45º and at 60º (WS 60º of knee flexion. Fifteen healthy control women and fifteen women

  20. Electromyographic monitoring and its anatomical implications in minimally invasive spine surgery.

    Science.gov (United States)

    Uribe, Juan S; Vale, Fernando L; Dakwar, Elias

    2010-12-15

    Literature review. The objective of this article is to examine current intraoperative electromyography (EMG) neurophysiologic monitoring methods and their application in minimally invasive techniques. We will also discuss the recent application of EMG and its anatomic implications to the minimally invasive lateral transpsoas approach to the spine. Minimally invasive techniques require that the same goals of surgery be achieved, with the hope of decreased morbidity to the patient. Unlike standard open procedures, direct visualization of the anatomy is decreased. To increase the safety of minimally invasive spine surgery, neurophysiological monitoring techniques have been developed. Review of the literature was performed using the National Center for Biotechnology Information databases using PUBMED/MEDLINE. All articles in the English language discussing the use of intraoperative EMG monitoring and minimally invasive spine surgery were reviewed. The role of EMG monitoring in special reference to the minimally invasive lateral transpsoas approach is also described. In total, 76 articles were identified that discussed the role of neuromonitoring in spine surgery. The majority of articles on EMG and spine surgery discuss the use of intraoperative neurophysiological monitoring (IOM) for safe and accurate pedicle screw placement. In general, there is a paucity of literature that pertains to intraoperative EMG neuromonitoring and minimally invasive spine surgery. Recently, EMG has been used during minimally invasive lateral transpsoas approach to the lumbar spine for interbody fusion. The addition of EMG to the lateral approach has contributed to decrease the complication rate from 30% to less than 1%. In minimally invasive approaches to the spine, the use of EMG IOM might provide additional safety, such as percutaneous pedicle screw placement, where visualization is limited compared with conventional open procedures. In addition to knowledge of the anatomy and image

  1. Rate of torque and electromyographic development during anticipated eccentric contraction is lower in previously strained hamstrings.

    Science.gov (United States)

    Opar, David A; Williams, Morgan D; Timmins, Ryan G; Dear, Nuala M; Shield, Anthony J

    2013-01-01

    The effect of prior strain injury on myoelectrical activity of the hamstrings during tasks requiring high rates of torque development has received little attention. To determine if recreational athletes with a history of unilateral hamstring strain injury will exhibit lower levels of myoelectrical activity during eccentric contraction, rate of torque development (RTD), and impulse (IMP) at 30, 50, and 100 milliseconds after the onset of myoelectrical activity or torque development in the previously injured limb compared with the uninjured limb. Case control study; Level of evidence, 3. Twenty-six recreational athletes were recruited. Of these, 13 athletes had a history of unilateral hamstring strain injury (all confined to biceps femoris long head), and 13 had no history of hamstring strain injury. Following familiarization, all athletes undertook isokinetic dynamometry testing and surface electromyography (integrated EMG; iEMG) assessment of the biceps femoris long head and medial hamstrings during eccentric contractions at -60 and -180 deg·s(-1). In the injured limb of the injured group, compared with the contralateral uninjured limb, RTD and IMP was lower during -60 deg·s(-1) eccentric contractions at 50 milliseconds (RTD: injured limb, 312.27 ± 191.78 N·m·s(-1) vs uninjured limb, 518.54 ± 172.81 N·m·s(-1), P = .008; IMP: injured limb, 0.73 ± 0.30 N·m·s vs uninjured limb, 0.97 ± 0.23 N·m·s, P = .005) and 100 milliseconds (RTD: injured limb, 280.03 ± 131.42 N·m·s(-1) vs uninjured limb, 460.54 ± 152.94 N·m·s(-1), P = .001; IMP: injured limb, 2.15 ± 0.89 N·m·s vs uninjured limb, 3.07 ± 0.63 N·m·s, P contraction. Biceps femoris long head muscle activation was lower at 100 milliseconds at both contraction speeds (-60 deg·s(-1), normalized iEMG activity [×1000]: injured limb, 26.25 ± 10.11 vs uninjured limb, 33.57 ± 8.29, P = .009; -180 deg·s(-1), normalized iEMG activity [×1000]: injured limb, 31.16 ± 10.01 vs uninjured limb, 39.64

  2. Electromyographic validation of the trapezius and serratus anterior muscles in the rowing and frontal-lateral cross, dumbbells exercises.

    Science.gov (United States)

    Büll, M L; Freitas, V; Vitti, M; Rosa, G J M

    2002-03-01

    The trapezius and serratus anterior muscles were studied in four modalities of rowing exercises executed with two grips, middle and closed, in comparison with the four different modalities of frontal-lateral cross, dumbbells exercise. It was used 24 male volunteers, 18 to 25 years old using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. The results showed that TS acted in a higher significant way in all the modalities of rowing than in the supine lateral raise, inclined supine lateral raise and reverse supine lateral raise, dumbbells exercices, and demonstrated no standing frontal-lateral cross, dumbbells. The SI acted more significantly difference among all the execution modalities of rowing and the inclined supine lateral raise, dumbbells exercises than in all the rowing exercises; even though the activity levels do not make us suggest them as an excellent group of exercises for the development of this muscle.

  3. Mastigação e atividade eletromiográfica em crianças com mordida cruzada posterior Mastication and electromyographic activity in children with posterior crossbite

    Directory of Open Access Journals (Sweden)

    Luciana Vitaliano Voi Trawitzki

    2009-01-01

    Full Text Available OBJETIVO: investigar a preferência mastigatória e o comportamento dos músculos mastigatórios, em crianças de 6 a 9 anos, com mordida cruzada posterior. MÉTODOS: 30 crianças foram selecionadas num serviço de Ortodontia de uma universidade pública. Após a concordância na participação no trabalho, foi realizada entrevista com a criança e seu responsável, para investigação de disfunção temporomandibular; análise da preferência mastigatória, por meio de registros em vídeo e avaliação eletromiográfica (EMG dos músculos masseter e temporal anterior, durante a mastigação solicitada, direita e esquerda, de uma goma de marcar. RESULTADOS: houve diferença significante na atividade EMG dos músculos masseter e temporal anterior entre os lados de trabalho e balanceio, porém não houve diferença estatística quando foram comparadas as atividades EMG entre os lados de mordida cruzada e não cruzada, tampouco entre os lados de preferência e não preferência mastigatória. CONCLUSÃO: na amostra estudada não se verificou assimetria funcional muscular estabelecida.PURPOSE: to investigate the masticatory preference and the behavior of masticatory muscles, in children between6 to 9-year old, with posterior crossbite. METHODS: 30 children were selected from the Orthodontical service of a public university. After consenting to take part in the study, there was an interview with the children and the parent, in order to investigate temporomandibular disorders; masticatory was analyzed through video recording and electromyographic (EMG evaluation of the masseter and anterior temporal, during the solicited mastication, on right and left, using chewing gum. RESULTS: there was a significant difference in the EMG activity of the masseter and temporal between work and balance sides, however there was no statistical differences in the comparison between crossbite side and no crossbite side, but neither between preference side and non the

  4. Ground reaction force and electromyographic activity of transfemoral amputee gait: a case series

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    Alex Sandra Oliveira de Cerqueira

    2013-01-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2013v15n1p16 Ground reaction forces (GRF and electromyographic activity form a part of the descriptive data that characterise the biomechanics of gait. The research of these parameters is important in establishing gait training and understanding the impact of amputation and prosthetic components on movement during the act of walking. Therefore, this case series describes the GRF and electromyographic activity in the gait of transfemoral amputees. A force plate was used to measure GRF, and an electromyographic system monitored the vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius lateralis muscles of the non-amputated leg. The average vertical and anteroposterior GRF time-curves, average electromyographic activity, and descriptor variables were then analysed. We observed decreases in vertical and anteroposterior GRF magnitudes as well as in anteroposterior GRF descriptor variables during the propulsive phase in the amputated leg. There were increases in phasic muscle activity and co-activation in the non-amputated leg. We concluded that, during walking, the unilateral transfemoral amputees (who were analysed in this case series developed lower GRF in the amputated limb and a longer period of electromyographic activity in the non-amputated limb.

  5. Detection of driving fatigue by using noncontact EMG and ECG signals measurement system.

    Science.gov (United States)

    Fu, Rongrong; Wang, Hong

    2014-05-01

    Driver fatigue can be detected by constructing a discriminant mode using some features obtained from physiological signals. There exist two major challenges of this kind of methods. One is how to collect physiological signals from subjects while they are driving without any interruption. The other is to find features of physiological signals that are of corresponding change with the loss of attention caused by driver fatigue. Driving fatigue is detected based on the study of surface electromyography (EMG) and electrocardiograph (ECG) during the driving period. The noncontact data acquisition system was used to collect physiological signals from the biceps femoris of each subject to tackle the first challenge. Fast independent component analysis (FastICA) and digital filter were utilized to process the original signals. Based on the statistical analysis results given by Kolmogorov-Smirnov Z test, the peak factor of EMG (p fatigue of drivers. The discriminant criterion of fatigue was obtained from the training samples by using Mahalanobis distance, and then the average classification accuracy was given by 10-fold cross-validation. The results showed that the method proposed in this paper can give well performance in distinguishing the normal state and fatigue state. The noncontact, onboard vehicle drivers' fatigue detection system was developed to reduce fatigue-related risks.

  6. A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions

    Directory of Open Access Journals (Sweden)

    Bret Contreras

    2015-09-01

    Full Text Available Background. The purpose of this study was to compare the peak electromyography (EMG of the most commonly-used position in the literature, the prone bent-leg (90° hip extension against manual resistance applied to the distal thigh (PRONE, to a novel position, the standing glute squeeze (SQUEEZE.Methods. Surface EMG electrodes were placed on the upper and lower gluteus maximus of thirteen recreationally active females (age = 28.9 years; height = 164 cm; body mass = 58.2 kg, before three maximum voluntary isometric contraction (MVIC trials for each position were obtained in a randomized, counterbalanced fashion.Results. No statistically significant (p < 0.05 differences were observed between PRONE (upper: 91.94%; lower: 94.52% and SQUEEZE (upper: 92.04%; lower: 85.12% for both the upper and lower gluteus maximus. Neither the PRONE nor SQUEEZE was more effective between all subjects.Conclusions. In agreement with other studies, no single testing position is ideal for every participant. Therefore, it is recommended that investigators employ multiple MVIC positions, when possible, to ensure accuracy. Future research should investigate a variety of gluteus maximus MVIC positions in heterogeneous samples.

  7. Bizarre repetitive discharges recorded with single fibre EMG.

    OpenAIRE

    Trontelj, J; Stålberg, E

    1983-01-01

    Single fibre EMG was used to record bizarre repetitive discharges in patients with chronic denervation or muscle disorders. The low variability of intervals between individual spike components on successive discharges suggests that the bizarre repetitive discharges are based on ephaptic impulse transmission from the muscle fibre starting the discharge (principal pacemaker) to the adjacent muscle fibres. The low variability of the interdischarge intervals is explained by ephaptic reactivation ...

  8. Fuzzy Control of a Robotic Arm using EMG Signals

    OpenAIRE

    Hidalgo, M.; Tene, G.; Sánchez Terán, Alberto

    2007-01-01

    This paper presents the control design of a robotic arm employing Fuzzy algorithms to interpret electromiographic (EMG) signals from the Flexor Carpi Radial