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.

Comparison of sEMG processing methods during whole-body vibration exercise.

Science.gov (United States)

Lienhard, Karin; Cabasson, Aline; Meste, Olivier; Colson, Serge S

2015-12-01

The objective was to investigate the influence of surface electromyography (sEMG) processing methods on the quantification of muscle activity during whole-body vibration (WBV) exercises. sEMG activity was recorded while the participants performed squats on the platform with and without WBV. The spikes observed in the sEMG spectrum at the vibration frequency and its harmonics were deleted using state-of-the-art methods, i.e. (1) a band-stop filter, (2) a band-pass filter, and (3) spectral linear interpolation. The same filtering methods were applied on the sEMG during the no-vibration trial. The linear interpolation method showed the highest intraclass correlation coefficients (no vibration: 0.999, WBV: 0.757-0.979) with the comparison measure (unfiltered sEMG during the no-vibration trial), followed by the band-stop filter (no vibration: 0.929-0.975, WBV: 0.661-0.938). While both methods introduced a systematic bias (P interpolation method and the band-stop filter was comparable. The band-pass filter was in poor agreement with the other methods (ICC: 0.207-0.697), unless the sEMG(RMS) was corrected for the bias (ICC ⩾ 0.931, %LOA ⩽ 32.3). In conclusion, spectral linear interpolation or a band-stop filter centered at the vibration frequency and its multiple harmonics should be applied to delete the artifacts in the sEMG signals during WBV. With the use of a band-stop filter it is recommended to correct the sEMG(RMS) for the bias as this procedure improved its performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Grip Force and 3D Push-Pull Force Estimation Based on sEMG and GRNN

Directory of Open Access Journals (Sweden)

Changcheng Wu

2017-06-01

Full Text Available The estimation of the grip force and the 3D push-pull force (push and pull force in the three dimension space from the electromyogram (EMG signal is of great importance in the dexterous control of the EMG prosthetic hand. In this paper, an action force estimation method which is based on the eight channels of the surface EMG (sEMG and the Generalized Regression Neural Network (GRNN is proposed to meet the requirements of the force control of the intelligent EMG prosthetic hand. Firstly, the experimental platform, the acquisition of the sEMG, the feature extraction of the sEMG and the construction of GRNN are described. Then, the multi-channels of the sEMG when the hand is moving are captured by the EMG sensors attached on eight different positions of the arm skin surface. Meanwhile, a grip force sensor and a three dimension force sensor are adopted to measure the output force of the human's hand. The characteristic matrix of the sEMG and the force signals are used to construct the GRNN. The mean absolute value and the root mean square of the estimation errors, the correlation coefficients between the actual force and the estimated force are employed to assess the accuracy of the estimation. Analysis of variance (ANOVA is also employed to test the difference of the force estimation. The experiments are implemented to verify the effectiveness of the proposed estimation method and the results show that the output force of the human's hand can be correctly estimated by using sEMG and GRNN method.

sEMG feature evaluation for identification of elbow angle resolution in graded arm movement.

Science.gov (United States)

Castro, Maria Claudia F; Colombini, Esther L; Aquino, Plinio T; Arjunan, Sridhar P; Kumar, Dinesh K

2014-11-25

Automatic and accurate identification of elbow angle from surface electromyogram (sEMG) is essential for myoelectric controlled upper limb exoskeleton systems. This requires appropriate selection of sEMG features, and identifying the limitations of such a system.This study has demonstrated that it is possible to identify three discrete positions of the elbow; full extension, right angle, and mid-way point, with window size of only 200 milliseconds. It was seen that while most features were suitable for this purpose, Power Spectral Density Averages (PSD-Av) performed best. The system correctly classified the sEMG against the elbow angle for 100% cases when only two discrete positions (full extension and elbow at right angle) were considered, while correct classification was 89% when there were three discrete positions. However, sEMG was unable to accurately determine the elbow position when five discrete angles were considered. It was also observed that there was no difference for extension or flexion phases.

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.

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.

Age related neuromuscular changes in sEMG of m. Tibialis Anterior using higher order statistics (Gaussianity & linearity test).

Science.gov (United States)

Siddiqi, Ariba; Arjunan, Sridhar P; Kumar, Dinesh K

2016-08-01

Age-associated changes in the surface electromyogram (sEMG) of Tibialis Anterior (TA) muscle can be attributable to neuromuscular alterations that precede strength loss. We have used our sEMG model of the Tibialis Anterior to interpret the age-related changes and compared with the experimental sEMG. Eighteen young (20-30 years) and 18 older (60-85 years) performed isometric dorsiflexion at 6 different percentage levels of maximum voluntary contractions (MVC), and their sEMG from the TA muscle was recorded. Six different age-related changes in the neuromuscular system were simulated using the sEMG model at the same MVCs as the experiment. The maximal power of the spectrum, Gaussianity and Linearity Test Statistics were computed from the simulated and experimental sEMG. A correlation analysis at α=0.05 was performed between the simulated and experimental age-related change in the sEMG features. The results show the loss in motor units was distinguished by the Gaussianity and Linearity test statistics; while the maximal power of the PSD distinguished between the muscular factors. The simulated condition of 40% loss of motor units with halved the number of fast fibers best correlated with the age-related change observed in the experimental sEMG higher order statistical features. The simulated aging condition found by this study corresponds with the moderate motor unit remodelling and negligible strength loss reported in literature for the cohorts aged 60-70 years.

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.

Evaluation of novel algorithm embedded in a wearable sEMG device for seizure detection

DEFF Research Database (Denmark)

Conradsen, Isa; Beniczky, Sandor; Wolf, Peter

2012-01-01

We implemented a modified version of a previously published algorithm for detection of generalized tonic-clonic seizures into a prototype wireless surface electromyography (sEMG) recording device. The method was modified to require minimum computational load, and two parameters were trained...... on prior sEMG data recorded with the device. Along with the normal sEMG recording, the device is able to set an alarm whenever the implemented algorithm detects a seizure. These alarms are annotated in the data file along with the signal. The device was tested at the Epilepsy Monitoring Unit (EMU......) at the Danish Epilepsy Center. Five patients were included in the study and two of them had generalized tonic-clonic seizures. All patients were monitored for 2–5 days. A double-blind study was made on the five patients. The overall result showed that the device detected four of seven seizures and had a false...

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).

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.

Estimation of Handgrip Force from SEMG Based on Wavelet Scale Selection.

Science.gov (United States)

Wang, Kai; Zhang, Xianmin; Ota, Jun; Huang, Yanjiang

2018-02-24

This paper proposes a nonlinear correlation-based wavelet scale selection technology to select the effective wavelet scales for the estimation of handgrip force from surface electromyograms (SEMG). The SEMG signal corresponding to gripping force was collected from extensor and flexor forearm muscles during the force-varying analysis task. We performed a computational sensitivity analysis on the initial nonlinear SEMG-handgrip force model. To explore the nonlinear correlation between ten wavelet scales and handgrip force, a large-scale iteration based on the Monte Carlo simulation was conducted. To choose a suitable combination of scales, we proposed a rule to combine wavelet scales based on the sensitivity of each scale and selected the appropriate combination of wavelet scales based on sequence combination analysis (SCA). The results of SCA indicated that the scale combination VI is suitable for estimating force from the extensors and the combination V is suitable for the flexors. The proposed method was compared to two former methods through prolonged static and force-varying contraction tasks. The experiment results showed that the root mean square errors derived by the proposed method for both static and force-varying contraction tasks were less than 20%. The accuracy and robustness of the handgrip force derived by the proposed method is better than that obtained by the former methods.

Design of sEMG assembly to detect external anal sphincter activity: a proof of concept.

Science.gov (United States)

Shiraz, Arsam; Leaker, Brian; Mosse, Charles Alexander; Solomon, Eskinder; Craggs, Michael; Demosthenous, Andreas

2017-10-31

Conditional trans-rectal stimulation of the pudendal nerve could provide a viable solution to treat hyperreflexive bladder in spinal cord injury. A set threshold of the amplitude estimate of the external anal sphincter surface electromyography (sEMG) may be used as the trigger signal. The efficacy of such a device should be tested in a large scale clinical trial. As such, a probe should remain in situ for several hours while patients attend to their daily routine; the recording electrodes should be designed to be large enough to maintain good contact while observing design constraints. The objective of this study was to arrive at a design for intra-anal sEMG recording electrodes for the subsequent clinical trials while deriving the possible recording and processing parameters. Having in mind existing solutions and based on theoretical and anatomical considerations, a set of four multi-electrode probes were designed and developed. These were tested in a healthy subject and the measured sEMG traces were recorded and appropriately processed. It was shown that while comparatively large electrodes record sEMG traces that are not sufficiently correlated with the external anal sphincter contractions, smaller electrodes may not maintain a stable electrode tissue contact. It was shown that 3 mm wide and 1 cm long electrodes with 5 mm inter-electrode spacing, in agreement with Nyquist sampling, placed 1 cm from the orifice may intra-anally record a sEMG trace sufficiently correlated with external anal sphincter activity. The outcome of this study can be used in any biofeedback, treatment or diagnostic application where the activity of the external anal sphincter sEMG should be detected for an extended period of time.

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.

Generating Human-Like Velocity-Adapted Jumping Gait from sEMG Signals for Bionic Leg’s Control

Directory of Open Access Journals (Sweden)

Weiwei Yu

2017-01-01

Full Text Available In the case of dynamic motion such as jumping, an important fact in sEMG (surface Electromyogram signal based control on exoskeletons, myoelectric prostheses, and rehabilitation gait is that multichannel sEMG signals contain mass data and vary greatly with time, which makes it difficult to generate compliant gait. Inspired by the fact that muscle synergies leading to dimensionality reduction may simplify motor control and learning, this paper proposes a new approach to generate flexible gait based on muscle synergies extracted from sEMG signal. Two questions were discussed and solved, the first one concerning whether the same set of muscle synergies can explain the different phases of hopping movement with various velocities. The second one is about how to generate self-adapted gait with muscle synergies while alleviating model sensitivity to sEMG transient changes. From the experimental results, the proposed method shows good performance both in accuracy and in robustness for producing velocity-adapted vertical jumping gait. The method discussed in this paper provides a valuable reference for the sEMG-based control of bionic robot leg to generate human-like dynamic gait.

Multichannel noninvasive human-machine interface via stretchable µm thick sEMG patches for robot manipulation

Science.gov (United States)

Zhou, Ying; Wang, Youhua; Liu, Runfeng; Xiao, Lin; Zhang, Qin; Huang, YongAn

2018-01-01

Epidermal electronics (e-skin) emerging in recent years offer the opportunity to noninvasively and wearably extract biosignals from human bodies. The conventional processes of e-skin based on standard microelectronic fabrication processes and a variety of transfer printing methods, nevertheless, unquestionably constrains the size of the devices, posing a serious challenge to collecting signals via skin, the largest organ in the human body. Herein we propose a multichannel noninvasive human-machine interface (HMI) using stretchable surface electromyography (sEMG) patches to realize a robot hand mimicking human gestures. Time-efficient processes are first developed to manufacture µm thick large-scale stretchable devices. With micron thickness, the stretchable µm thick sEMG patches show excellent conformability with human skin and consequently comparable electrical performance with conventional gel electrodes. Combined with the large-scale size, the multichannel noninvasive HMI via stretchable µm thick sEMG patches successfully manipulates the robot hand with eight different gestures, whose precision is as high as conventional gel electrodes array.

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.

Age and Electromyographic Frequency Alterations during Walking in Children with Cerebral Palsy

OpenAIRE

Lauer, Richard T.; Pierce, Samuel R.; Tucker, Carole A.; Barbe, Mary F.; Prosser, Laura A.

2009-01-01

The use of surface electromyography (sEMG) recorded during ambulation has provided valuable insight into motor development and changes with age in the pediatric population. However, no studies have reported sEMG differences with age in the children with cerebral palsy (CP). In this study, data from 50 children were divided retrospectively into four groups, representing either an older (above the age of 7 years) or younger (below the age of 7 years) age group with either typical development (T...

A sEMG model with experimentally based simulation parameters.

Science.gov (United States)

Wheeler, Katherine A; Shimada, Hiroshima; Kumar, Dinesh K; Arjunan, Sridhar P

2010-01-01

A differential, time-invariant, surface electromyogram (sEMG) model has been implemented. While it is based on existing EMG models, the novelty of this implementation is that it assigns more accurate distributions of variables to create realistic motor unit (MU) characteristics. Variables such as muscle fibre conduction velocity, jitter (the change in the interpulse interval between subsequent action potential firings) and motor unit size have been considered to follow normal distributions about an experimentally obtained mean. In addition, motor unit firing frequencies have been considered to have non-linear and type based distributions that are in accordance with experimental results. Motor unit recruitment thresholds have been considered to be related to the MU type. The model has been used to simulate single channel differential sEMG signals from voluntary, isometric contractions of the biceps brachii muscle. The model has been experimentally verified by conducting experiments on three subjects. Comparison between simulated signals and experimental recordings shows that the Root Mean Square (RMS) increases linearly with force in both cases. The simulated signals also show similar values and rates of change of RMS to the experimental signals.

Use of sEMG in identification of low level muscle activities: features based on ICA and fractal dimension.

Science.gov (United States)

Naik, Ganesh R; Kumar, Dinesh K; Arjunan, Sridhar

2009-01-01

This paper has experimentally verified and compared features of sEMG (Surface Electromyogram) such as ICA (Independent Component Analysis) and Fractal Dimension (FD) for identification of low level forearm muscle activities. The fractal dimension was used as a feature as reported in the literature. The normalized feature values were used as training and testing vectors for an Artificial neural network (ANN), in order to reduce inter-experimental variations. The identification accuracy using FD of four channels sEMG was 58%, and increased to 96% when the signals are separated to their independent components using ICA.

Inverse relationship between the complexity of midfoot kinematics and muscle activation in patients with medial tibial stress syndrome

DEFF Research Database (Denmark)

Rathleff, M S; Samani, Afshin; Olesen, C G

2011-01-01

Medial tibial stress syndrome is a common overuse injury characterized by pain located on the medial side of the lower leg during weight bearing activities such as gait. The purpose of this study was to apply linear and nonlinear methods to compare the structure of variability of midfoot kinematics...... and surface electromyographic (SEMG) signals between patients with medial tibial stress syndrome and healthy controls during gait. Fourteen patients diagnosed with medial tibial stress syndrome and 11 healthy controls were included from an orthopaedic clinic. SEMG from tibialis anterior and the soleus muscles...... as well as midfoot kinematics were recorded during 20 consecutive gait cycles. Permuted sample entropy and permutation entropy were used as a measure of complexity from SEMG signals and kinematics. SEMG signals in patients with medial tibial stress syndrome were characterized by higher structural...

Relationship between oxygen uptake slow component and surface EMG during heavy exercise in humans: influence of pedal rate.

Science.gov (United States)

Vercruyssen, Fabrice; Missenard, Olivier; Brisswalter, Jeanick

2009-08-01

The aim of this study was to test the hypothesis that extreme pedal rates contributed to the slow component of oxygen uptake (VO(2) SC) in association with changes in surface electromyographic (sEMG) during heavy-cycle exercise. Eight male trained cyclists performed two square-wave transitions at 50 and 110 rpm at a work rate that would elicit a VO(2) corresponding to 50% of the difference between peak VO(2) and the ventilatory threshold. Pulmonary gas exchange was measured breath-by-breath and sEMG was obtained from the vastus lateralis and medialis muscles. Integrated EMG flow (QiEMG) and mean power frequency (MPF) were computed. The relative amplitude of the VO(2) SC was significantly higher during the 110-rpm bout (556+/-186 ml min(-1), Pexercise only during the 110-rpm bout and were associated with the greater amplitude of the VO(2) SC observed for this condition (Pmotor units recruitment pattern, muscle energy turnover and muscle temperature have been suggested to explain the different VO(2) SC to heavy pedal rate bouts.

Electromyographic Grasp Recognition for a Five Fingered Robotic Hand

Directory of Open Access Journals (Sweden)

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.

Preferred sensor sites for surface EMG signal decomposition

International Nuclear Information System (INIS)

Zaheer, Farah; Roy, Serge H; De Luca, Carlo J

2012-01-01

Technologies for decomposing the electromyographic (EMG) signal into its constituent motor unit action potential trains have become more practical by the advent of a non-invasive methodology using surface EMG (sEMG) sensors placed on the skin above the muscle of interest (De Luca et al 2006 J. Neurophysiol. 96 1646–57 and Nawab et al 2010 Clin. Neurophysiol. 121 1602–15). This advancement has widespread appeal among researchers and clinicians because of the ease of use, reduced risk of infection, and the greater number of motor unit action potential trains obtained compared to needle sensor techniques. In this study we investigated the influence of the sensor site on the number of identified motor unit action potential trains in six lower limb muscles and one upper limb muscle with the intent of locating preferred sensor sites that provided the greatest number of decomposed motor unit action potential trains, or motor unit yield. Sensor sites rendered varying motor unit yields throughout the surface of a muscle. The preferred sites were located between the center and the tendinous areas of the muscle. The motor unit yield was positively correlated with the signal-to-noise ratio of the detected sEMG. The signal-to-noise ratio was inversely related to the thickness of the tissue between the sensor and the muscle fibers. A signal-to-noise ratio of 3 was found to be the minimum required to obtain a reliable motor unit yield. (paper)

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…

Surface electromyographic amplitude does not identify differences in neural drive to synergistic muscles.

Science.gov (United States)

Martinez-Valdes, Eduardo; Negro, Francesco; Falla, Deborah; De Nunzio, Alessandro Marco; Farina, Dario

2018-04-01

Surface electromyographic (EMG) signal amplitude is typically used to compare the neural drive to muscles. We experimentally investigated this association by studying the motor unit (MU) behavior and action potentials in the vastus medialis (VM) and vastus lateralis (VL) muscles. Eighteen participants performed isometric knee extensions at four target torques [10, 30, 50, and 70% of the maximum torque (MVC)] while high-density EMG signals were recorded from the VM and VL. The absolute EMG amplitude was greater for VM than VL ( P differences in EMG amplitude can be due to both differences in the neural drive and in the size of the MU action potentials, we indirectly inferred the neural drives received by the two muscles by estimating the synaptic inputs received by the corresponding motor neuron pools. For this purpose, we analyzed the increase in discharge rate from recruitment to target torque for motor units matched by recruitment threshold in the two muscles. This analysis indicated that the two muscles received similar levels of neural drive. Nonetheless, the size of the MU action potentials was greater for VM than VL ( P difference explained most of the differences in EMG amplitude between the two muscles (~63% of explained variance). These results indicate that EMG amplitude, even following normalization, does not reflect the neural drive to synergistic muscles. Moreover, absolute EMG amplitude is mainly explained by the size of MU action potentials. NEW & NOTEWORTHY Electromyographic (EMG) amplitude is widely used to compare indirectly the strength of neural drive received by synergistic muscles. However, there are no studies validating this approach with motor unit data. Here, we compared between-muscles differences in surface EMG amplitude and motor unit behavior. The results clarify the limitations of surface EMG to interpret differences in neural drive between muscles.

Evaluation of higher order statistics parameters for multi channel sEMG using different force levels.

Science.gov (United States)

Naik, Ganesh R; Kumar, Dinesh K

2011-01-01

The electromyograpy (EMG) signal provides information about the performance of muscles and nerves. The shape of the muscle signal and motor unit action potential (MUAP) varies due to the movement of the position of the electrode or due to changes in contraction level. This research deals with evaluating the non-Gaussianity in Surface Electromyogram signal (sEMG) using higher order statistics (HOS) parameters. To achieve this, experiments were conducted for four different finger and wrist actions at different levels of Maximum Voluntary Contractions (MVCs). Our experimental analysis shows that at constant force and for non-fatiguing contractions, probability density functions (PDF) of sEMG signals were non-Gaussian. For lesser MVCs (below 30% of MVC) PDF measures tends to be Gaussian process. The above measures were verified by computing the Kurtosis values for different MVCs.

Electromyographic activity and 6RM strength in bench press on stable and unstable surfaces.

Science.gov (United States)

Saeterbakken, Atle H; Fimland, Marius S

2013-04-01

The purpose of the study was to compare 6-repetition maximum (6RM) loads and muscle activity in bench press on 3 surfaces, namely, stable bench, balance cushion, and Swiss ball. Sixteen healthy, resistance-trained men (age 22.5 ± 2.0 years, stature 1.82 ± 6.6 m, and body mass 82.0 ± 7.8 kg) volunteered for 3 habituation/strength testing sessions and 1 experimental session. In randomized order on the 3 surfaces, 6RM strength and electromyographic activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were assessed. Relative to stable bench, the 6RM strength was approximately 93% for balance cushion (p ≤ 0.001) and approximately 92% for Swiss ball (p = 0.008); the pectoralis major electromyographic (EMG) activity was approximately 90% using the balance cushion (p = 0.080) and approximately 81% using Swiss ball (p = 0.006); the triceps EMG was approximately 79% using the balance cushion (p = 0.028) and approximately 69% using the Swiss ball (p = 0.002). Relative to balance cushion, the EMG activity in pectoralis, triceps, and erector spinae using Swiss ball was approximately 89% (p = 0.016), approximately 88% (p = 0.014) and approximately 80% (p = 0.020), respectively. In rectus abdominis, the EMG activity relative to Swiss ball was approximately 69% using stable bench (p = 0.042) and approximately 65% using the balance cushion (p = 0.046). Similar EMG activities between stable and unstable surfaces were observed for deltoid anterior, biceps brachii, and oblique external. In conclusion, stable bench press had greater 6RM strength and triceps and pectoralis EMG activity compared with the unstable surfaces. These findings have implications for athletic training and rehabilitation, because they demonstrate an inferior effect of unstable surfaces on muscle activation of prime movers and strength in bench press. If an unstable surface in bench press is desirable, a balance cushion should

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

Comparison between sEMG and force as control interfaces to support planar arm movements in adults with Duchenne: a feasibility study.

Science.gov (United States)

Lobo-Prat, Joan; Nizamis, Kostas; Janssen, Mariska M H P; Keemink, Arvid Q L; Veltink, Peter H; Koopman, Bart F J M; Stienen, Arno H A

2017-07-12

Adults with Duchenne muscular dystrophy (DMD) can benefit from devices that actively support their arm function. A critical component of such devices is the control interface as it is responsible for the human-machine interaction. Our previous work indicated that surface electromyography (sEMG) and force-based control with active gravity and joint-stiffness compensation were feasible solutions for the support of elbow movements (one degree of freedom). In this paper, we extend the evaluation of sEMG- and force-based control interfaces to simultaneous and proportional control of planar arm movements (two degrees of freedom). Three men with DMD (18-23 years-old) with different levels of arm function (i.e. Brooke scores of 4, 5 and 6) performed a series of line-tracing tasks over a tabletop surface using an experimental active arm support. The arm movements were controlled using three control methods: sEMG-based control, force-based control with stiffness compensation (FSC), and force-based control with no compensation (FNC). The movement performance was evaluated in terms of percentage of task completion, tracing error, smoothness and speed. For subject S1 (Brooke 4) FNC was the preferred method and performed better than FSC and sEMG. FNC was not usable for subject S2 (Brooke 5) and S3 (Brooke 6). Subject S2 presented significantly lower movement speed with sEMG than with FSC, yet he preferred sEMG since FSC was perceived to be too fatiguing. Subject S3 could not successfully use neither of the two force-based control methods, while with sEMG he could reach almost his entire workspace. Movement performance and subjective preference of the three control methods differed with the level of arm function of the participants. Our results indicate that all three control methods have to be considered in real applications, as they present complementary advantages and disadvantages. The fact that the two weaker subjects (S2 and S3) experienced the force-based control

Cervico-mandibular muscle activity in females with chronic cervical pain

OpenAIRE

T. Lang; R. Parker; T. Burgess

2013-01-01

Pathophysiological mechanisms behind pain in chroniccervical musculoskeletal conditions (MSC) in office workers remainunclear. Chronic cervical pain has established links with temporomandibular(TM) disorders. Yet there is no current published evidence to reportwhether individuals with cervical dysfunction exhibit altered masseterand cervical extensor (CE) muscle activity. Objective: To explore CE andmasseter surface electromyographic (sEMG) activity and teeth clenchinghabits in females with c...

Classification of rhythmic locomotor patterns in electromyographic signals using fuzzy sets

Directory of Open Access Journals (Sweden)

Thrasher Timothy A

2011-12-01

Full Text Available Abstract Background Locomotor control is accomplished by a complex integration of neural mechanisms including a central pattern generator, spinal reflexes and supraspinal control centres. Patterns of muscle activation during walking exhibit an underlying structure in which groups of muscles seem to activate in united bursts. Presented here is a statistical approach for analyzing Surface Electromyography (SEMG data with the goal of classifying rhythmic "burst" patterns that are consistent with a central pattern generator model of locomotor control. Methods A fuzzy model of rhythmic locomotor patterns was optimized and evaluated using SEMG data from a convenience sample of four able-bodied individuals. As well, two subjects with pathological gait participated: one with Parkinson's Disease, and one with incomplete spinal cord injury. Subjects walked overground and on a treadmill while SEMG was recorded from major muscles of the lower extremities. The model was fit to half of the recorded data using non-linear optimization and validated against the other half of the data. The coefficient of determination, R2, was used to interpret the model's goodness of fit. Results Using four fuzzy burst patterns, the model was able to explain approximately 70-83% of the variance in muscle activation during treadmill gait and 74% during overground gait. When five burst functions were used, one function was found to be redundant. The model explained 81-83% of the variance in the Parkinsonian gait, and only 46-59% of the variance in spinal cord injured gait. Conclusions The analytical approach proposed in this article is a novel way to interpret multichannel SEMG signals by reducing the data into basic rhythmic patterns. This can help us better understand the role of rhythmic patterns in locomotor control.

SEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture

Science.gov (United States)

Qianxiang, Zhou; Chao, Ma; Xiaohui, Zheng

sEMG analysis of astronaut upper arm during isotonic muscle actions with normal standing posture*1 Introduction Now the research on the isotonic muscle actions by using Surface Electromyography (sEMG) is becoming a pop topic in fields of astronaut life support training and rehabilitations. And researchers paid more attention on the sEMG signal processes for reducing the influence of noise which is produced during monitoring process and the fatigue estimation of isotonic muscle actions with different force levels by using the parameters which are obtained from sEMG signals such as Condition Velocity(CV), Median Frequency(MDF), Mean Frequency(MNF) and so on. As the lucubrated research is done, more and more research on muscle fatigue issue of isotonic muscle actions are carried out with sEMG analysis and subjective estimate system of Borg scales at the same time. In this paper, the relationship between the variable for fatigue based on sEMG and the Borg scale during the course of isotonic muscle actions of the upper arm with different contraction levels are going to be investigated. Methods 13 young male subjects(23.4±2.45years, 64.7±5.43Kg, 171.7±5.41cm) with normal standing postures were introduced to do isotonic actions of the upper arm with different force levels(10% MVC, 30%MVC and 50%MVC). And the MVC which means maximal voluntary contraction was obtained firstly in the experiment. Also the sEMG would be recorded during the experiments; the Borg scales would be recorded for each contraction level. By using one-third band octave method, the fatigue variable (p) based on sEMG were set up and it was expressed as p = i g(fi ) · F (fi ). And g(fi ) is defined as the frequent factor which was 0.42+0.5 cos(π fi /f0 )+0.08 cos(2π fi /f0 ), 0 f0 . According to the equations, the p could be computed and the relationship between variable p and the Borg scale would be investigated. Results In the research, three kinds of fitted curves between variable p and Borg

Simultaneous Force Regression and Movement Classification of Fingers via Surface EMG within a Unified Bayesian Framework.

Science.gov (United States)

Baldacchino, Tara; Jacobs, William R; Anderson, Sean R; Worden, Keith; Rowson, Jennifer

2018-01-01

This contribution presents a novel methodology for myolectric-based control using surface electromyographic (sEMG) signals recorded during finger movements. A multivariate Bayesian mixture of experts (MoE) model is introduced which provides a powerful method for modeling force regression at the fingertips, while also performing finger movement classification as a by-product of the modeling algorithm. Bayesian inference of the model allows uncertainties to be naturally incorporated into the model structure. This method is tested using data from the publicly released NinaPro database which consists of sEMG recordings for 6 degree-of-freedom force activations for 40 intact subjects. The results demonstrate that the MoE model achieves similar performance compared to the benchmark set by the authors of NinaPro for finger force regression. Additionally, inherent to the Bayesian framework is the inclusion of uncertainty in the model parameters, naturally providing confidence bounds on the force regression predictions. Furthermore, the integrated clustering step allows a detailed investigation into classification of the finger movements, without incurring any extra computational effort. Subsequently, a systematic approach to assessing the importance of the number of electrodes needed for accurate control is performed via sensitivity analysis techniques. A slight degradation in regression performance is observed for a reduced number of electrodes, while classification performance is unaffected.

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.

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

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.

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.

The vastus lateralis neuromuscular activity during all-out cycling exercise.

Science.gov (United States)

Bercier, Stephane; Halin, Renaud; Ravier, Philippe; Kahn, Jean-Francois; Jouanin, Jean-Claude; Lecoq, Anne-Marie; Buttelli, Olivier

2009-10-01

The objective of this work was to study modifications in motor control through surface electromyographic (sEMG) activity during a very short all-out cycling exercise. Twelve male cyclists (age 23+/-4 years) participated in this study. After a warm-up period, each subject performed three all-out cycling exercises of 6s separated by 2 min of complete rest. This protocol was repeated three times with a minimum of 2 days between each session. The braking torque imposed on cycling motion was 19 Nm. The sEMG of the vastus lateralis was recorded during the first seven contractions of the sprint. Time-frequency analysis of sEMG was performed using continuous wavelet transform. The mean power frequency (MPF, qualitative modifications in the recruitment of motor units) and signal energy (a quantitative indicator of modifications in the motor units recruitment) were computed for the frequency range 10-500 Hz. sEMG energy increased (P0.05) between contraction number 1 and 2, decreased (P recruitment of motor units (MUs) at the beginning of the sprint followed by a preferential recruitment of faster MUs at the end of the sprint, respectively.

An ICA-EBM-Based sEMG Classifier for Recognizing Lower Limb Movements in Individuals With and Without Knee Pathology.

Science.gov (United States)

Naik, Ganesh R; Selvan, S Easter; Arjunan, Sridhar P; Acharyya, Amit; Kumar, Dinesh K; Ramanujam, Arvind; Nguyen, Hung T

2018-03-01

Surface electromyography (sEMG) data acquired during lower limb movements has the potential for investigating knee pathology. Nevertheless, a major challenge encountered with sEMG signals generated by lower limb movements is the intersubject variability, because the signals recorded from the leg or thigh muscles are contingent on the characteristics of a subject such as gait activity and muscle structure. In order to cope with this difficulty, we have designed a three-step classification scheme. First, the multichannel sEMG is decomposed into activities of the underlying sources by means of independent component analysis via entropy bound minimization. Next, a set of time-domain features, which would best discriminate various movements, are extracted from the source estimates. Finally, the feature selection is performed with the help of the Fisher score and a scree-plot-based statistical technique, prior to feeding the dimension-reduced features to the linear discriminant analysis. The investigation involves 11 healthy subjects and 11 individuals with knee pathology performing three different lower limb movements, namely, walking, sitting, and standing, which yielded an average classification accuracy of 96.1% and 86.2%, respectively. While the outcome of this study per se is very encouraging, with suitable improvement, the clinical application of such an sEMG-based pattern recognition system that distinguishes healthy and knee pathological subjects would be an attractive consequence.

Muscle force output and electromyographic activity in squats with various unstable surfaces.

Science.gov (United States)

Saeterbakken, Atle H; Fimland, Marius S

2013-01-01

The purpose of the study was to compare force output and muscle activity of leg and trunk muscles in isometric squats executed on stable surface (i.e., floor), power board, BOSU ball, and balance cone. Fifteen healthy men (23.3 ± 2.7 years, mass: 80.5 ± 8.5 kg, height: 1.81 ± 0.09 m) volunteered. The force output and electromyographic (EMG) activities of the rectus femoris, vastus medialis, vastus lateralis, biceps femoris, soleus, rectus abdominis, oblique external, and erector spinae were assessed. The order of the surfaces was randomized. One familiarization session was executed before the experimental test. Compared with stable surface (749 ± 222 N), the force output using power board was similar (-7%, p = 0.320) but lower for BOSU ball (-19%, p = 0.003) and balance cone (-24%, p ≤ 0.001). The force output using BOSU ball and balance cone was approximately 13% (p = 0.037) and approximately 18% (p = 0.001) less than the power board. There were similar EMG activities between the surfaces in all muscles except for rectus femoris, in which stable squat provided greater EMG activity than did the other exercises (p = 0.004-0.030). Lower EMG activity was observed in the rectus femoris using balance cone compared with the BOSU ball (p = 0.030). In conclusion, increasing the instability of the surface during maximum effort isometric squats usually maintains the muscle activity of lower-limb and superficial trunk muscles although the force output is reduced. This suggests that unstable surfaces in the squat may be beneficial in rehabilitation and as a part of periodized training programs, because similar muscle activity can be achieved with reduced loads.

Repeatability of grasp recognition for robotic hand prosthesis control based on sEMG data.

Science.gov (United States)

Palermo, Francesca; Cognolato, Matteo; Gijsberts, Arjan; Muller, Henning; Caputo, Barbara; Atzori, Manfredo

2017-07-01

Control methods based on sEMG obtained promising results for hand prosthetics. Control system robustness is still often inadequate and does not allow the amputees to perform a large number of movements useful for everyday life. Only few studies analyzed the repeatability of sEMG classification of hand grasps. The main goals of this paper are to explore repeatability in sEMG data and to release a repeatability database with the recorded experiments. The data are recorded from 10 intact subjects repeating 7 grasps 12 times, twice a day for 5 days. The data are publicly available on the Ninapro web page. The analysis for the repeatability is based on the comparison of movement classification accuracy in several data acquisitions and for different subjects. The analysis is performed using mean absolute value and waveform length features and a Random Forest classifier. The accuracy obtained by training and testing on acquisitions at different times is on average 27.03% lower than training and testing on the same acquisition. The results obtained by training and testing on different acquisitions suggest that previous acquisitions can be used to train the classification algorithms. The inter-subject variability is remarkable, suggesting that specific characteristics of the subjects can affect repeatibility and sEMG classification accuracy. In conclusion, the results of this paper can contribute to develop more robust control systems for hand prostheses, while the presented data allows researchers to test repeatability in further analyses.

The reliability of a maximal isometric hip strength and simultaneous surface EMG screening protocol in elite, junior rugby league athletes.

Science.gov (United States)

Charlton, Paula C; Mentiplay, Benjamin F; Grimaldi, Alison; Pua, Yong-Hao; Clark, Ross A

2017-02-01

Firstly to describe the reliability of assessing maximal isometric strength of the hip abductor and adductor musculature using a hand held dynamometry (HHD) protocol with simultaneous wireless surface electromyographic (sEMG) evaluation of the gluteus medius (GM) and adductor longus (AL). Secondly, to describe the correlation between isometric strength recorded with the HHD protocol and a laboratory standard isokinetic device. Reliability and correlational study. A sample of 24 elite, male, junior, rugby league athletes, age 16-20 years participated in repeated HHD and isometric Kin-Com (KC) strength testing with simultaneous sEMG assessment, on average (range) 6 (5-7) days apart by a single assessor. Strength tests included; unilateral hip abduction (ABD) and adduction (ADD) and bilateral ADD assessed with squeeze (SQ) tests in 0 and 45° of hip flexion. HHD demonstrated good to excellent inter-session reliability for all outcome measures (ICC (2,1) =0.76-0.91) and good to excellent association with the laboratory reference KC (ICC (2,1) =0.80-0.88). Whilst intra-session, inter-trial reliability of EMG activation and co-activation outcome measures ranged from moderate to excellent (ICC (2,1) =0.70-0.94), inter-session reliability was poor (all ICC (2,1) Isometric strength testing of the hip ABD and ADD musculature using HHD may be measured reliably in elite, junior rugby league athletes. Due to the poor inter-session reliability of sEMG measures, it is not recommended for athlete screening purposes if using the techniques implemented in this study. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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

2012-01-01

Objectives: 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. Material and Methods: 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 acti-vity 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. Results: 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. Conclusions: 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. Key words:Unilateral crossbite, mandibular shift, jaw muscles, sEMG, early mixed dentition. PMID:22926468

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....... 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...... recordings did not deteriorate the NMR spectra. The VARPRO time domain fitting routine was very suitable for estimating 31P muscle spectra. With these methods it was possible to accurately estimate parameters describing metabolic and electrical changes during rest, exercise and the entire recovery period...

Work related perceived stress and muscle activity during standardized computer work among female computer users

DEFF Research Database (Denmark)

Larsman, P; Thorn, S; Søgaard, K

2009-01-01

The current study investigated the associations between work-related perceived stress and surface electromyographic (sEMG) parameters (muscle activity and muscle rest) during standardized simulated computer work (typing, editing, precision, and Stroop tasks). It was part of the European case......-control study, NEW (Neuromuscular assessment in the Elderly Worker). The present cross-sectional study was based on a questionnaire survey and sEMG measurements among Danish and Swedish female computer users aged 45 or older (n=49). The results show associations between work-related perceived stress...... and trapezius muscle activity and rest during standardized simulated computer work, and provide partial empirical support for the hypothesized pathway of stress induced muscle activity in the association between an adverse psychosocial work environment and musculoskeletal symptoms in the neck and shoulder....

An isometric muscle force estimation framework based on a high-density surface EMG array and an NMF algorithm

Science.gov (United States)

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

2017-08-01

Objective. To realize accurate muscle force estimation, a novel framework is proposed in this paper which can extract the input of the prediction model from the appropriate activation area of the skeletal muscle. Approach. Surface electromyographic (sEMG) signals from the biceps brachii muscle during isometric elbow flexion were collected with a high-density (HD) electrode grid (128 channels) and the external force at three contraction levels was measured at the wrist synchronously. The sEMG envelope matrix was factorized into a matrix of basis vectors with each column representing an activation pattern and a matrix of time-varying coefficients by a nonnegative matrix factorization (NMF) algorithm. The activation pattern with the highest activation intensity, which was defined as the sum of the absolute values of the time-varying coefficient curve, was considered as the major activation pattern, and its channels with high weighting factors were selected to extract the input activation signal of a force estimation model based on the polynomial fitting technique. Main results. Compared with conventional methods using the whole channels of the grid, the proposed method could significantly improve the quality of force estimation and reduce the electrode number. Significance. The proposed method provides a way to find proper electrode placement for force estimation, which can be further employed in muscle heterogeneity analysis, myoelectric prostheses and the control of exoskeleton devices.

Postnatal changes in electromyographic signals during piglet growth, and in relation to muscle fibre types

DEFF Research Database (Denmark)

Andersen, Ninette Kieme; Ravn, L.S.; Guy, J.H.

2008-01-01

This study uses non-invasive evoked surface electromyography (SEMG) to investigate postnatal muscle development in pigs, and to assess any correlation between recorded signal parameters and muscle fibre types in two different skeletal muscles. Four litters (n=43) of Large White x Landrace pigs were...... used. Evoked SEMG mesurements were taken on days 2, 5, 14, 26, 60 and 151 post partum from m. Longissimus dorsi (LD) and on days 14, 26, 60 and 151 post partum from m. Biceps femoris (BF). A third of each litter was slaughtered at days 27, 61 and 153 post partum. Biopsy samples for LD and BF were taken...... to categorize day 5 post partum, whilst for BF significant increases occurred from days 14 to 26 post partum. Fibre type development in both muscles showed a significant decrease in type IIA fibre number (Ptype IIB fibre number (P

Electromyographic activity of the trunk extensor muscles: effect of varying hip position and lumbar posture during Roman chair exercise.

Science.gov (United States)

Mayer, John M; Verna, Joe L; Manini, Todd M; Mooney, Vert; Graves, James E

2002-11-01

To evaluate the effect of hip position and lumbar posture on the surface electromyographic activity of the trunk extensors during Roman chair exercise. Descriptive, repeated measures. University-based musculoskeletal research laboratory. Twelve healthy volunteers (7 men, 5 women; age range, 18-35y) without a history of low back pain were recruited from a university setting. Not applicable. Surface electromyographic activity was recorded from the lumbar extensor, gluteal, and hamstring musculature during dynamic Roman chair exercise. For each muscle group, electromyographic activity (mV/rep) was compared among exercises with internal hip rotation and external hip rotation and among exercises by using a typical lumbar posture (nonbiphasic) and a posture that accentuated lumbar lordosis (biphasic). For the lumbar extensors, electromyographic activity during exercise was 18% greater with internal hip rotation than external hip rotation (Phamstrings, there was no difference in electromyographic activity between internal and external hip rotation or between biphasic and nonbiphasic postures (P >.05). The level of recruitment of the lumbar extensors can be modified during Roman chair exercise by altering hip position and lumbar posture. Clinicians can use these data to develop progressive exercise protocols for the lumbar extensors with a variety of resistance levels without the need for complex equipment. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Novel Feature Modelling the Prediction and Detection of sEMG Muscle Fatigue towards an Automated Wearable System

Directory of Open Access Journals (Sweden)

Mohamed R. Al-Mulla

2010-05-01

Full Text Available Surface Electromyography (sEMG activity of the biceps muscle was recorded from ten subjects performing isometric contraction until fatigue. A novel feature (1D spectro_std was used to extract the feature that modeled three classes of fatigue, which enabled the prediction and detection of fatigue. Initial results of class separation were encouraging, discriminating between the three classes of fatigue, a longitudinal classification on Non-Fatigue and Transition-to-Fatigue shows 81.58% correct classification with accuracy 0.74 of correct predictions while the longitudinal classification on Transition-to-Fatigue and Fatigue showed lower average correct classification of 66.51% with a positive classification accuracy 0.73 of correct prediction. Comparison of the 1D spectro_std with other sEMG fatigue features on the same dataset show a significant improvement in classification, where results show a significant 20.58% (p < 0.01 improvement when using the 1D spectro_std to classify Non-Fatigue and Transition-to-Fatigue. In classifying Transition-to-Fatigue and Fatigue results also show a significant improvement over the other features giving 8.14% (p < 0.05 on average of all compared features.

Is there any change in pelvic floor electromyography during the first 6 months after radical retropubic prostatectomy?

Science.gov (United States)

Hacad, Claudia R; Glazer, Howard I; Zambon, João Paulo C; Burti, Juliana S; Almeida, Fernando G

2015-03-01

The aim of this study is to determine electromyographic pelvic floor muscles activity during the first 6 months post RRP and its relationship to urinary continence. Thirty-eight men (mean age of 63.1 ± 5.7 year) with prostate cancer scheduled for open radical retropubic prostatectomy were evaluated. pelvic radiotherapy, systemic or neurologic diseases, pre-operative International Prostate Symptoms Score (IPSS) >7 and OABq ≥8. Surface electromyography (sEMG) evaluation, IPSS, Urinary Distress Inventory, Incontinence Impact Questionnaire, and Overactive Bladder Questionnaire-short form were applied before and at 1, 3, and 6 months after RRP. Six months after surgery, 18 men (47.4 %) presented urinary leakage. The sEMG evaluations within the first 6 months presented changes in fast contraction amplitude (p = 0.006), rest amplitude after fast contraction (p = 0.04), 10 s sustained contraction mean amplitude (p = 0.024) and final rest amplitude (p = 0.011). We observed that continent and incontinent patients as a group presented electromyographic changes during the first 6 months after radical prostatectomy that could be justified by the denervation/reinnervation of the external urethral sphincter. This finding is consistent with the adaptation of the pelvic floor musculature to the new urethral sphincter condition following surgery.

Electromyographic evaluation in children orthodontically treated for skeletal Class II malocclusion: Comparison of two treatment techniques.

Science.gov (United States)

Ortu, Eleonora; Pietropaoli, Davide; Adib, Fray; Masci, Chiara; Giannoni, Mario; Monaco, Annalisa

2017-11-16

Objective To compare the clinical efficacy of two techniques for fabricating a Bimler device by assessing the patient's surface electromyography (sEMG) activity at rest before treatment and six months after treatment. Methods Twenty-four patients undergoing orthodontic treatment were enrolled in the study; 12 formed the test group and wore a Bimler device fabricated with a Myoprint impression using neuromuscular orthodontic technique and 12 formed the control group and were treated by traditional orthodontic technique with a wax bite in protrusion. The "rest" sEMG of each patient was recorded prior to treatment and six months after treatment. Results The neuromuscular-designed Bimler device was more comfortable and provided better treatment results than the traditional Bimler device. Conclusion This study suggests that the patient group subjected to neuromuscular orthodontic treatment had a treatment outcome with more relaxed masticatory muscles and better function versus the traditional orthodontic treatment.

Virtual Control of Prosthetic Hand Based on Grasping Patterns and Estimated Force from Semg

Directory of Open Access Journals (Sweden)

Zhu Gao-Ke

2016-01-01

Full Text Available Myoelectric prosthetic hands aim to serve upper limb amputees. The myoelectric control of the hand grasp action is a kind of real-time or online method. Thus it is of great necessity to carry on a study of online prosthetic hand electrical control. In this paper, the strategy of simultaneous EMG decoding of grasping patterns and grasping force was realized by controlling a virtual multi-degree-freedom prosthetic hand and a real one-degree-freedom prosthetic hand simultaneously. The former realized the grasping patterns from the recognition of the sEMG pattern. The other implemented the grasping force from sEMG force decoding. The results show that the control method is effective and feasible.

Stable tooth contacts in intercuspal occlusion makes for utilities of the jaw elevators during maximal voluntary clenching.

Science.gov (United States)

Wang, X-R; Zhang, Y; Xing, N; Xu, Y-F; Wang, M-Q

2013-05-01

Data are inconsistent concerning whether the level of the surface electromyographic (SEMG) activity of jaw-closing muscles increases when biting forces elevated during maximal voluntary clenching (MVC). In this study, T-Scan III system and BioEMG III system were used to record bite force, occlusal contacts and SEMG activity of the anterior temporalis (TA) and of the masseter muscles (MM) simultaneously. Recordings were obtained from 16 healthy young adult males during different conditions: (i) a fast MVC from resting position to intercuspal position (ICP); (ii) mandibular movements from ICP to protrusive or lateral edge-to-edge positions with teeth in contact with biting; (iii) a fast MVC in protrusive and lateral edge-to-edge positions. A higher level of SEMG activity was associated with a higher bite force during occluding movements (P < 0.05). However, during fast MVC from rest to ICP, the largest number of occlusal contacts was achieved and distributed more symmetrically, the highest level of biting force was obtained, but the SEMG activity of the jaw elevator muscles was reduced compared with its maximum level (P < 0.05). This phenomenon was not observed during the fast MVC in protrusive or lateral edge-to-edge positions. The present results that a lower SEMG activity was associated with the largest number of occlusal contacts and the highest level of bite force during centric MVC demonstrated a complex integration of jaw-closing muscles when a stable occlusion is present. © 2013 Blackwell Publishing Ltd.

Effect of electrocardiographic contamination on surface electromyography assessment of back muscles.

Science.gov (United States)

Hu, Yong; Mak, Joseph N F; Luk, Keith D K

2009-02-01

The purpose of this study was to demonstrate the relative effect of electrocardiography (ECG) on back muscle surface electromyography (SEMG) parameters and their corresponding sensitivity in low back pain (LBP) assessment. Back muscle SEMG activities were recorded from 17 healthy subjects and 18 chronic LBP patients under static postures (straight sitting and upright standing), and dynamic action (flexion-extension). ECG cancellation based on independent component analysis (ICA) method was performed. Root mean square (RMS) and median frequency (MF) of raw and denoised SEMG data were computed respectively. Multiple comparisons were then performed. A consistent trend of change (increased MF and decreased RMS) followed ECG removal was noticed. In particular, in SEMG measurements under static postures, a significant decrease in RMS (pcorruption by ECG artifacts on SEMG measurements was found to be more serious and prominent in static postures than that in dynamic action. After ECG removal, significant improvements in the ability of SEMG to discriminate LBP patients from healthy subjects were seen in RMS amplitude recorded while standing (peffect of ECG contamination on back muscles SEMG parameters and LBP assessment.

Estimation of muscle fatigue using surface electromyography and near-infrared spectroscopy.

Science.gov (United States)

Taelman, Joachim; Vanderhaegen, Joke; Robijns, Mieke; Naulaers, Gunnar; Spaepen, Arthur; Van Huffel, Sabine

2011-01-01

This study looks at various parameters, derived from surface electromyography (sEMG) and Near Infrared Spectroscopy (NIRS) and their relationship in muscle fatigue during a static elbow flexion until exhaustion as well as during a semidynamic exercise.We found a linear increasing trend for a corrected amplitude parameter and a linear decreasing slope for the frequency content of the sEMG signal. The tissue oxygenation index (TOI) extracted from NIRS recordings showed a four-phase response for all the subjects. A strong correlation between frequency content of the sEMG signal and TOI was established. We can conclude that both sEMG and NIRS give complementary information concerning muscle fatigue.

A computational model to investigate the effect of pennation angle on surface electromyogram of Tibialis Anterior.

Directory of Open Access Journals (Sweden)

Diptasree Maitra Ghosh

Full Text Available This study has described and experimentally validated the differential electrodes surface electromyography (sEMG model for tibialis anterior muscles during isometric contraction. This model has investigated the effect of pennation angle on the simulated sEMG signal. The results show that there is no significant effect of pennation angle in the range 0° to 20° to the single fibre action potential shape recorded on the skin surface. However, the changes with respect to pennation angle are observed in sEMG amplitude, frequency and fractal dimension. It is also observed that at different levels of muscle contractions there is similarity in the relationships with Root Mean Square, Median Frequency, and Fractal Dimension of the recorded and simulated sEMG signals.

An electromyographic study on the sequential recruitment of bilateral sternocleidomastoid and masseter muscle activity during gum chewing.

Science.gov (United States)

Guo, S-X; Li, B-Y; Zhang, Y; Zhou, L-J; Liu, L; Widmalm, S-E; Wang, M-Q

2017-08-01

Mandibular functions are associated with electromyographic activity of the jaw muscles and also the sternocleidomastoid muscle (SCM). The precise spatiotemporal relation of SCM and masticatory muscles activities during chewing is worthy of investigation. To analyse the sequential recruitment of SCM and masseter activities during chewing as indicated by the spatiotemporal locations of their activity peaks. Jaw movements and bilateral surface electromyographic activity of SCM and masseter were recorded during gum chewing in 20 healthy subjects. The timing order was decided by comparing the length of time from the time when the opening started to the time when the surface electromyographic activity reached its peak value. Spatial order was analysed by locating the peak electromyographic activity onto a standard chewing cycle which was created based on 15 unilateral chewing cycles. Paired t-test, one-way ANOVA and Student-Newman-Keuls post-test were used for comparisons. Although the Time to Peak for the balancing side SCM appeared shorter than for the other three tested muscles, most often it did not reach a level of significance. However, the location of the balancing side SCM's peak activity was further from the terminal chewing position (TCP) than the working side SCM and bilateral masseters (P < 0·05). The balancing side SCM activity reached its peak significantly further away from TCP than the other three tested muscles during chewing. Further studies with spatiotemporal variables included should be helpful to understand the roles of the head, neck and jaw muscles in orofacial and cervical dysfunctional problems. © 2017 John Wiley & Sons Ltd.

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.

Effects of 12-wk eccentric calf muscle training on muscle-tendon glucose uptake and SEMG in patients with chronic Achilles tendon pain.

Science.gov (United States)

Masood, Tahir; Kalliokoski, Kari; Magnusson, S Peter; Bojsen-Møller, Jens; Finni, Taija

2014-07-15

High-load eccentric exercises have been a key component in the conservative management of chronic Achilles tendinopathy. This study investigated the effects of a 12-wk progressive, home-based eccentric rehabilitation program on ankle plantar flexors' glucose uptake (GU) and myoelectric activity and Achilles tendon GU. A longitudinal study design with control (n = 10) and patient (n = 10) groups was used. Surface electromyography (SEMG) from four ankle plantar flexors and GU from the same muscles and the Achilles tendon were measured during submaximal intermittent isometric plantar flexion task. The results indicated that the symptomatic leg was weaker (P eccentric rehabilitation. Additionally, the rehabilitation resulted in greater GU in both soleus (P tendon GU than the controls (P effect on the tendon GU. Concerning SEMG, at baseline, soleus showed more relative activity in the symptomatic leg compared with both the asymptomatic and control legs (P Eccentric rehabilitation was effective in decreasing subjective severity of Achilles tendinopathy. It also resulted in redistribution of relative electrical activity, but not metabolic activity, within the triceps surae muscle. Copyright © 2014 the American Physiological Society.

Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity

Directory of Open Access Journals (Sweden)

Minjae Kim

2015-07-01

Full Text Available Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

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

The effects of a single intercuspal interference on electromyographic characteristics of human masticatory muscles during maximal voluntary teeth clenching.

Science.gov (United States)

Ferrario, V F; Sforza, C; Serrao, G; Colombo, A; Schmitz, J H

1999-07-01

In 13 healthy subjects (eight men and five women, mean age, 22 years), an aluminum intercuspal interference (height, 0.25 mm) was placed on the maxillary right first premolar to study its effect on the contractile symmetry of the right and left masseter and anterior temporalis muscles when measured through a Percentage Overlapping Coefficient (POC), derived from surface electromyographic recordings of maximum voluntary teeth clenching. Additionally, and to estimate the potential of the experimental intercuspal interference to induce lateral displacement of the mandible, a Torque Coefficient (TC) was derived from surface electromyographic recordings. The conclusion was that the experimental occlusal interference gave rise to asymmetric contractile activity in the studied mandibular elevator muscles as well as a potential to displace the mandible in a lateral direction.

Continuous Estimation of Human Multi-Joint Angles From sEMG Using a State-Space Model.

Science.gov (United States)

Ding, Qichuan; Han, Jianda; Zhao, Xingang

2017-09-01

Due to the couplings among joint-relative muscles, it is a challenge to accurately estimate continuous multi-joint movements from multi-channel sEMG signals. Traditional approaches always build a nonlinear regression model, such as artificial neural network, to predict the multi-joint movement variables using sEMG as inputs. However, the redundant sEMG-data are always not distinguished; the prediction errors cannot be evaluated and corrected online as well. In this work, a correlation-based redundancy-segmentation method is proposed to segment the sEMG-vector including redundancy into irredundant and redundant subvectors. Then, a general state-space framework is developed to build the motion model by regarding the irredundant subvector as input and the redundant one as measurement output. With the built state-space motion model, a closed-loop prediction-correction algorithm, i.e., the unscented Kalman filter (UKF), can be employed to estimate the multi-joint angles from sEMG, where the redundant sEMG-data are used to reject model uncertainties. After having fully employed the redundancy, the proposed method can provide accurate and smooth estimation results. Comprehensive experiments are conducted on the multi-joint movements of the upper limb. The maximum RMSE of the estimations obtained by the proposed method is 0.16±0.03, which is significantly less than 0.25±0.06 and 0.27±0.07 (p < 0.05) obtained by common neural networks.

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...... 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...... reliable for ≈50% of participants. Although using sEMG to assess swallowing musculature function is easier to perform clinically and more comfortable to patients than invasive measures, as the measurement of muscle activity using TMS is unreliable, the use of sEMG for this muscle group is not recommended...

A soft robotic exomusculature glove with integrated sEMG sensing for hand rehabilitation.

Science.gov (United States)

Delph, Michael A; Fischer, Sarah A; Gauthier, Phillip W; Luna, Carlos H Martinez; Clancy, Edward A; Fischer, Gregory S

2013-06-01

Stroke affects 750,000 people annually, and 80% of stroke survivors are left with weakened limbs and hands. Repetitive hand movement is often used as a rehabilitation technique in order to regain hand movement and strength. In order to facilitate this rehabilitation, a robotic glove was designed to aid in the movement and coordination of gripping exercises. This glove utilizes a cable system to open and close a patients hand. The cables are actuated by servomotors, mounted in a backpack weighing 13.2 lbs including battery power sources. The glove can be controlled in terms of finger position and grip force through switch interface, software program, or surface myoelectric (sEMG) signal. The primary control modes of the system provide: active assistance, active resistance and a preprogrammed mode. This project developed a working prototype of the rehabilitative robotic glove which actuates the fingers over a full range of motion across one degree-of-freedom, and is capable of generating a maximum 15N grip force.

Neural network committees for finger joint angle estimation from surface EMG signals

Directory of Open Access Journals (Sweden)

Reddy Narender P

2009-01-01

Full Text Available Abstract Background In virtual reality (VR systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG together with the actual joint angle measurements were obtained while the subject was performing flexion-extension rotation of the index finger at three speeds. Several neural networks were trained to predict the joint angle from the parameters extracted from the SEMG signals. The best networks were selected to form six committees. The neural network committees were evaluated using data from new subjects. Results There was hysteresis in the measured SMEG signals during the flexion-extension cycle. However, neural network committees were able to predict the joint angle with reasonable accuracy. RMS errors ranged from 0.085 ± 0.036 for fast speed finger-extension to 0.147 ± 0.026 for slow speed finger extension, and from 0.098 ± 0.023 for the fast speed finger flexion to 0.163 ± 0.054 for slow speed finger flexion. Conclusion Although hysteresis was observed in the measured SEMG signals, the committees of neural networks were able to predict the finger joint angle from SEMG signals.

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

Effects of Push-ups Plus Sling Exercise on Muscle Activation and Cross-sectional Area of the Multifidus Muscle in Patients with Low Back Pain.

Science.gov (United States)

Kim, Gye-Yeop; Kin, Se-Hun

2013-12-01

[Purpose] The purpose of this study was to examine the effect of lumbar stability exercises on chronic low back pain by using sling exercise and push-ups. [Subjects] Thirty adult subjects with chronic back pain participated, with 10 adults being assigned to each of 3 exercise groups: general physical therapy (PT), lumbar stability using sling exercises (Sling Ex), and sling exercise plus push-ups (Sling Ex+PU). Each group trained for 30 minutes 3 times a week for 6 weeks. The Oswestry Disability Index (ODI), surface electromyographic (sEMG) activity of the lumbar muscles, and cross-sectional area of the multifidus muscle on computed tomography (CT) were evaluated before and at 2, 4, and 6 weeks of therapy. [Results] A significant decrease in ODI was seen in all therapy groups, and this change was greater in the Sling Ex and Sling Ex+PU groups than in the PT group. No changes in sEMG activity were noted in the PT group, whereas significant increases in the sEMG activities of all lumbar muscles were found in the other 2 groups. The increases in the sEMG activities of the rectus abdominis and internal and external oblique muscles of the abdomen were greater in the Sling Ex+PU group than in the other 2 groups. [Conclusion] These findings demonstrate that Sling Ex+PU, similar to normal lumbar stabilization exercise, is effective in activating and improving the function of the lumbar muscles. These results suggest that Sling Ex+PU has a positive impact on stabilization of the lumbar region.

Cervico-mandibular muscle activity in females with chronic cervical pain

Directory of Open Access Journals (Sweden)

T. Lang

2013-12-01

Full Text Available Pathophysiological mechanisms behind pain in chroniccervical musculoskeletal conditions (MSC in office workers remainunclear. Chronic cervical pain has established links with temporomandibular(TM disorders. Yet there is no current published evidence to reportwhether individuals with cervical dysfunction exhibit altered masseterand cervical extensor (CE muscle activity. Objective: To explore CE andmasseter surface electromyographic (sEMG activity and teeth clenchinghabits in females with chronic cervical dysfunction and no TM disorder.Design: Descriptive cross-sectional correlational study with singleblinding.Participants: University students and staff with or without chroniccervical pain and no TM involvement. Methods: Descriptive and paindata captured from Research Diagnostic Criteria for TM disorders, NeckDisability Index, Computer Usage, Brief Pain Inventory, and EuroQoL-5Dquestionnaires. Female participants allocated to a chronic cervical (n = 20 and a control group (n = 22. Investigator blindedto the study groups recorded sEMG of bilateral masseter and CE muscles (C4/5 level at rest and during light teeth clenching.Results: No differences in socio-demographic profile; or in masseter or CE sEMG activity at rest or during light clench betweengroups. The pain group had higher scores for pain, reported a daytime teeth clenching habit, and had worse scores for the healthrelatedquality of life (HRQoL sub-sections for pain, anxiety/depression, and lower scores for perceived health status. Conclusion:No relationship established between cervico-mandibular sEMG activity and reported disability in females with chronic cervicaldysfunction and no TM disorder. Association between biopsychosocial factors of teeth clenching and anxiety/depression highlightscomplex pathophysiological mechanisms in chronic recurrent cervical pain.

An electromyographic analysis of two handwriting grasp patterns.

Science.gov (United States)

de Almeida, Pedro Henrique Tavares Queiroz; da Cruz, Daniel Marinho Cezar; Magna, Luis Alberto; Ferrigno, Iracema Serrat Vergotti

2013-08-01

Handwriting is a fundamental skill needed for the development of daily-life activities during lifetime and can be performed using different forms to hold the writing object. In this study, we monitored the sEMG activity of trapezius, biceps brachii, extensor carpi radialis brevis and flexor digitorum superficialis during a handwriting task with two groups of subjects using different grasp patterns. Twenty-four university students (thirteen males and eleven females; mean age of 22.04±2.8years) were included in this study. We randomly invited 12 subjects that used the Dynamic Tripod grasp and 12 subjects that used the Static Tripod grasp. The static tripod group showed statistically significant changes in the sEMG activity of trapezium and biceps brachii muscles during handwriting when compared to dynamic tripod group's subjects. No significant differences were found in extensor carpi radialis brevis and flexor digitorum superficialis activities among the two groups. The findings in this study suggest an increased activity of proximal muscles among subjects using a transitional grasp, indicating potential higher energy expenditure and muscular harm with the maintenance of this motor pattern in handwriting tasks, especially during the progression in academic life. Copyright © 2013 Elsevier Ltd. All rights reserved.

The use of a custom-made mouthguard stabilizes the electromyographic activity of the masticatory muscles among Karate-Dō athletes.

Science.gov (United States)

Raquel, Gilsane; Namba, Eli Luis; Bonotto, Daniel; Ribeiro Rosa, Edvaldo Antônio; Trevilatto, Paula Cristina; Naval Machado, Maria Ângela; Vianna-Lara, Michelle Santos; Azevedo-Alanis, Luciana Reis

2017-01-01

To analyze and compare the electromyographic activity of the temporal (anterior portion) and masseter muscles among Karate-Dō athletes before and after training, with and without the use of a mouthguard. Twenty athletes (14 males and 6 females) with a mean age of 23.7 ± 7.5 years participated. They had surface electromyography recordings taken of their bilateral temporal and masseter muscles before and after training under the following conditions: no mouthguard, with a ready-made mouthguard, and with a custom-made mouthguard. Activity was examined at mandibular rest, while clenching, and at maximum voluntary contraction. The data were normalized using the mean maximum voluntary contraction. The right (p = 0.005) and left (p = 0.015) temporal muscles showed significantly lower electromyographic activity with a custom-made mouthguard compared with no mouthguard after training while clenching. The electromyographic activity of the temporal and masseter muscles did not show significant differences when tested at mandibular rest and while clenching before or after training with a custom-made mouthguard (p > 0.05). The use of a custom-made mouthguard preserved participants' electromyographic profiles before and after training; thus, they allow for stable muscle activity during the training of Karate-Dō athletes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electromyographic permutation entropy quantifies diaphragmatic denervation and reinnervation.

Directory of Open Access Journals (Sweden)

Christopher Kramer

Full Text Available Spontaneous reinnervation after diaphragmatic paralysis due to trauma, surgery, tumors and spinal cord injuries is frequently observed. A possible explanation could be collateral reinnervation, since the diaphragm is commonly double-innervated by the (accessory phrenic nerve. Permutation entropy (PeEn, a complexity measure for time series, may reflect a functional state of neuromuscular transmission by quantifying the complexity of interactions across neural and muscular networks. In an established rat model, electromyographic signals of the diaphragm after phrenicotomy were analyzed using PeEn quantifying denervation and reinnervation. Thirty-three anesthetized rats were unilaterally phrenicotomized. After 1, 3, 9, 27 and 81 days, diaphragmatic electromyographic PeEn was analyzed in vivo from sternal, mid-costal and crural areas of both hemidiaphragms. After euthanasia of the animals, both hemidiaphragms were dissected for fiber type evaluation. The electromyographic incidence of an accessory phrenic nerve was 76%. At day 1 after phrenicotomy, PeEn (normalized values was significantly diminished in the sternal (median: 0.69; interquartile range: 0.66-0.75 and mid-costal area (0.68; 0.66-0.72 compared to the non-denervated side (0.84; 0.78-0.90 at threshold p<0.05. In the crural area, innervated by the accessory phrenic nerve, PeEn remained unchanged (0.79; 0.72-0.86. During reinnervation over 81 days, PeEn normalized in the mid-costal area (0.84; 0.77-0.86, whereas it remained reduced in the sternal area (0.77; 0.70-0.81. Fiber type grouping, a histological sign for reinnervation, was found in the mid-costal area in 20% after 27 days and in 80% after 81 days. Collateral reinnervation can restore diaphragm activity after phrenicotomy. Electromyographic PeEn represents a new, distinctive assessment characterizing intramuscular function following denervation and reinnervation.

An investigation into the bilateral functional differences of the lower limb muscles in standing and walking

Directory of Open Access Journals (Sweden)

Shengyun Liang

2016-08-01

Full Text Available To date, most studies use surface electromyographic (sEMG signals as the control source on active rehabilitation robots, and unilateral data are collected based on the gait symmetry hypothesis, which has caused much controversy. The purpose of this study is to quantitatively evaluate the sEMG activity asymmetry of bilateral muscles in lower extremities during functional tasks. Nine participants were instructed to perform static and dynamic steady state tests. sEMG signals from the tibialis anterior, soleus, medial gastrocnemius and lateral gastrocnemius muscles of bilateral lower extremities were recorded in the experiments. Muscle activities are quantified in terms of sEMG amplitude. We investigated whether characteristics of left limb and the one of the right limb have the same statistical characteristics during functional tasks using The Wilcoxon rank-sum test, and studied dynamic signal irregularity degree for sEMG activities via sample entropy. The total of muscle activities showed significant differences between left limb and right limb during the static steady state (p = 0.000. For dynamic steady states, there were significant differences for most muscle activities between left limb and right limb at different speeds (p = 0.000. Nevertheless, there was no difference between the lateral gastrocnemius for bilateral limb at 2.0 kilometers per hour (p = 0.060. For medial gastrocnemius, differences were not found between left limb and right limb at 1.0 and 3.0 kilometers per hours (p = 0.390 and p = 0.085, respectively. Similarly, there was no difference for soleus at 3.0 kilometers per hour (p = 0.115. The importance of the differences in muscle activities between left limb and right limb were found. These results can potentially be used for evaluating lower limb extremity function of special populations (elderly people or stroke patients in an objective and simple method.

Simultaneous recording of EEG and electromyographic polygraphy increases the diagnostic yield of video-EEG monitoring.

Science.gov (United States)

Hill, Aron T; Briggs, Belinda A; Seneviratne, Udaya

2014-06-01

To investigate the usefulness of adjunctive electromyographic (EMG) polygraphy in the diagnosis of clinical events captured during long-term video-EEG monitoring. A total of 40 patients (21 women, 19 men) aged between 19 and 72 years (mean 43) investigated using video-EEG monitoring were studied. Electromyographic activity was simultaneously recorded with EEG in four patients selected on clinical grounds. In these patients, surface EMG electrodes were placed over muscles suspected to be activated during a typical clinical event. Of the 40 patients investigated, 24 (60%) were given a diagnosis, whereas 16 (40%) remained undiagnosed. All four patients receiving adjunctive EMG polygraphy obtained a diagnosis, with three of these diagnoses being exclusively reliant on the EMG recordings. Specifically, one patient was diagnosed with propriospinal myoclonus, another patient was diagnosed with facio-mandibular myoclonus, and a third patient was found to have bruxism and periodic leg movements of sleep. The information obtained from surface EMG recordings aided the diagnosis of clinical events captured during video-EEG monitoring in 7.5% of the total cohort. This study suggests that EEG-EMG polygraphy may be used as a technique of improving the diagnostic yield of video-EEG monitoring in selected cases.

Surface electromyography as a screening method for evaluation of dysphagia and odynophagia

Science.gov (United States)

Vaiman, Michael; Eviatar, Ephraim

2009-01-01

Objective Patients suspected of having swallowing disorders, could highly benefit from simple diagnostic screening before being referred to specialist evaluations. The article analyzes various instrumental methods of dysphagia assessment, introduces surface electromyography (sEMG) to carry out rapid assessment of such patients, and debates proposed suggestions for sEMG screening protocol in order to identify abnormal deglutition. Data sources Subject related books and articles from 1813 to 2007 were obtained through library search, MEDLINE (1949–2007) and EMBASE (1975–2007). Methods Specifics steps for establishing the protocol for applying the technique for screening purposes (e.g., evaluation of specific muscles), the requirements for diagnostic sEMG equipment, the sEMG technique itself, and defining the tests suitable for assessing deglutition (e.g., saliva, normal, and excessive swallows and uninterrupted drinking of water) are presented in detail. SEMG is compared with other techniques in terms of cost, timing, involvement of radiation, etc. Results According to the published data, SEMG of swallowing is a simple and reliable method for screening and preliminary differentiation among dysphagia and odynophagia of various origins. This noninvasive radiation-free examination has a low level of discomfort, and is simple, time-saving and inexpensive to perform. The major weakness of the method seems to be inability for precise diagnostic of neurologically induced dysphagia. Conclusion With standardization of the technique and an established normative database, sEMG might serve as a reliable screening method for optimal patient management but cannot serve for proper investigation of neurogenic dysphagia. PMID:19232090

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 ...

Duration of observation required in detecting fasciculation potentials in amyotrophic lateral sclerosis using high-density surface EMG

Directory of Open Access Journals (Sweden)

Zhou Ping

2012-10-01

Full Text Available Abstract Background High-density surface electromyography (HD-SEMG has recently emerged as a potentially useful tool in the evaluation of amyotrophic lateral sclerosis (ALS. This study addresses a practical constraint that arises when applying HD-SEMG for supporting the diagnosis of ALS; specifically, how long the surface EMG should be recorded before one can be confident that fasciculation potentials (FPs are absent in a muscle being tested. Methods HD-SEMG recordings of 29 muscles from 11 ALS patients were analyzed. We used the distribution of intervals between FPs, and estimated the observation duration needed to record from one to five FPs with a probability approaching unity. Such an approach was previously tested by Mills with a concentric needle electrode. Results We found that the duration of recording was up to 70 s in order to record a single FP with a probability approaching unity. Increasing recording time to 2 minutes, the probability of recording five FPs approached approximately 0.95. Conclusions HD-SEMG appears to be a suitable method for capturing FPs comparable to intramuscular needle EMG.

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.

A model for generating Surface EMG signal of m. Tibialis Anterior.

Science.gov (United States)

Siddiqi, Ariba; Kumar, Dinesh; Arjunan, Sridhar P

2014-01-01

A model that simulates surface electromyogram (sEMG) signal of m. Tibialis Anterior has been developed and tested. This has a firing rate equation that is based on experimental findings. It also has a recruitment threshold that is based on observed statistical distribution. Importantly, it has considered both, slow and fast type which has been distinguished based on their conduction velocity. This model has assumed that the deeper unipennate half of the muscle does not contribute significantly to the potential induced on the surface of the muscle and has approximated the muscle to have parallel structure. The model was validated by comparing the simulated and the experimental sEMG signal recordings. Experiments were conducted on eight subjects who performed isometric dorsiflexion at 10, 20, 30, 50, 75, and 100% maximal voluntary contraction. Normalized root mean square and median frequency of the experimental and simulated EMG signal were computed and the slopes of the linearity with the force were statistically analyzed. The gradients were found to be similar (p>0.05) for both experimental and simulated sEMG signal, validating the proposed model.

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.

Decreased torque and electromyographic activity in the extensor thigh muscles in chondromalacia patellae.

Science.gov (United States)

Väätäinen, U; Airaksinen, O; Jaroma, H; Kiviranta, I

1995-01-01

The alterations in thigh muscle properties of chondromalacia patellae patients during isometric and dynamic endurance tests were studied using a variokinetic knee testing system linked to surface EMG. A total of 41 patients (chondromalacia group) with arthroscopically certified chondromalacia of the patella were studied. The control group consisted of 31 healthy adult volunteers with no history of knee pain or trauma. Peak torque values were 21% (p chondromalacia group than in the control group. The decrease in the ratio between integrated EMG (IEMG) and measured force were found in all parts of the quadriceps femoris muscle in patients with chondromalacia of the patella in isometric extension. No change in the normalized IEMG levels of the thigh muscles were found between chondromalacia patients and controls in dynamic endurance test. The severity of the chondromalacia of the patella did not affect the level of electromyographic activation in thigh muscles. The ratio of normalized EMG levels of vastus medialis and vastus lateralis did not differ between the groups. The present study showed that chondromalacia patellae patients have reduced force and electromyographic activation levels of quadriceps femoris muscle. Especially, the explosive strength of the quadriceps femoris muscle is reduced.

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.

Swallowing in patients with Parkinson's disease: a surface electromyography study.

Science.gov (United States)

Ws Coriolano, Maria das Graças; R Belo, Luciana; Carneiro, Danielle; G Asano, Amdore; Al Oliveira, Paulo José; da Silva, Douglas Monteiro; G Lins, Otávio

2012-12-01

Our goal was to study deglutition of Parkinson's disease (PD) patients and normal controls (NC) using surface electromyography (sEMG). The study included 15 patients with idiopathic PD and 15 age-matched normal controls. Surface electromyography was collected over the suprahyoid muscle group. Conditions were the following: swallow at once 10 and 20 ml of water and 5 and 10 ml of yogurt of firm consistency, and freely drink 100 ml of water. During swallowing, durations of sEMG were significantly longer in PD patients than in normal controls but no significant differences of amplitudes were found. Eighty percent of the PD patients and 20 % of the NC needed more than one swallow to consume 20 ml of water, while 70 % of the PD patients and none of the NC needed more than one swallow to consume 5 ml of yogurt. PD patients took significantly more time and needed significantly more swallows to drink 100 ml of water than normal controls. We conclude that sEMG might be a simple and useful tool to study and monitor deglutition in PD patients.

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.

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

were analyzed from 11 consecutive patients. Our method is based on a high-pass filtering with a cutoff at 150 Hz, and monitoring a count of zero crossings with a hysteresis of $\\pm 50\\,\\mu \\hbox{V}$ . Based on data from one sEMG electrode (on the deltoid muscle), we achieved a sensitivity of 100...

Correlation analysis between surface electromyography and continuous-wave near-infrared spectroscopy parameters during isometric exercise to volitional fatigue

OpenAIRE

ŞAYLİ, Ömer; AKIN, Ata; ÇOTUK, Hasan Birol

2014-01-01

In this study, the process of muscular fatigue was examined using surface electromyography (sEMG) and continuous-wave near-infrared spectroscopy (cw-NIRS) simultaneously during an isometric hand grip exercise at 50% and 75% of the maximal voluntary contraction (MVC), sustained until volitional fatigue. The mean frequency of the sEMG decreased during the whole exercise, whereas the root mean square had a tendency to increase. Oxyhemoglobin/deoxyhemoglobin concentration changes computed ...

Detecting fatigue thresholds from electromyographic signals: A systematic review on approaches and methodologies.

Science.gov (United States)

Ertl, Peter; Kruse, Annika; Tilp, Markus

2016-10-01

The aim of the current paper was to systematically review the relevant existing electromyographic threshold concepts within the literature. The electronic databases MEDLINE and SCOPUS were screened for papers published between January 1980 and April 2015 including the keywords: neuromuscular fatigue threshold, anaerobic threshold, electromyographic threshold, muscular fatigue, aerobic-anaerobictransition, ventilatory threshold, exercise testing, and cycle-ergometer. 32 articles were assessed with regard to their electromyographic methodologies, description of results, statistical analysis and test protocols. Only one article was of very good quality. 21 were of good quality and two articles were of very low quality. The review process revealed that: (i) there is consistent evidence of one or two non-linear increases of EMG that might reflect the additional recruitment of motor units (MU) or different fiber types during fatiguing cycle ergometer exercise, (ii) most studies reported no statistically significant difference between electromyographic and metabolic thresholds, (iii) one minute protocols with increments between 10 and 25W appear most appropriate to detect muscular threshold, (iv) threshold detection from the vastus medialis, vastus lateralis, and rectus femoris is recommended, and (v) there is a great variety in study protocols, measurement techniques, and data processing. Therefore, we recommend further research and standardization in the detection of EMGTs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of upper limb muscle fatigue based on surface electromyography.

Science.gov (United States)

Zhou, Qianxiang; Chen, Yuhong; Ma, Chao; Zheng, Xiaohui

2011-10-01

Fatigue is believed to be a major contributory factor to occupational injuries in machine operators. The development of accurate and usable techniques to measure operator fatigue is therefore important. In this study, we used a novel method based on surface electromyography (sEMG) of the biceps brachii and the Borg scale to evaluate local muscle fatigue in the upper limb after isometric muscle action. Thirteen young males performed isometric actions with the upper limb at different force levels. sEMG activities of the biceps brachii were recorded during the actions. Borg scales were used to evaluate the subjective sensation of local fatigue of the biceps brachii after the actions. sEMG activities were analyzed using the one-third band octave method, and an equation to determine the degree of fatigue was derived based on the relationship between the variable and the Borg scale. The results showed that the relationship could be expressed by a conic curve, and could be used to evaluate muscle fatigue during machine operation.

Independence Between Two Channels of Surface Electromyogram Signal to Measure the Loss of Motor Units

Directory of Open Access Journals (Sweden)

Arjunan Sridhar P.

2015-06-01

Full Text Available This study has investigated the relationship in the connectivity of motor units in surface electromyogram (sEMG of biceps brachii muscle. It is hypothesized that with ageing, there is reduction/loss in number of motor units, leading to reduction in the independence between the channels of the recorded muscle activity. Two channels of sEMG were recorded during three levels of isometric muscle contraction: 50 %, 75 % and 100 % maximal voluntary contraction (MVC. 73 subjects (age range 20-70 participated in the experiments. The independence in channel index (ICI between the two sEMG recording locations was computed using the independent components and Frobenius norm. ANOVA Statistical analysis was performed to test the effect of age (loss of motor units and level of contraction on ICI. The results show that the ICI among the older cohort was significantly lower compared with the younger adults. This research study has shown that the reduction in number of motor units is reflected by the reduction in the ICI of the sEMG signal.

Age-Associated Changes in the Spectral and Statistical Parameters of Surface Electromyogram of Tibialis Anterior.

Science.gov (United States)

Siddiqi, Ariba; Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2016-01-01

Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20-30 years) and 18 older (60-85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes.

Classification of Anticipatory Signals for Grasp and Release from Surface Electromyography

Science.gov (United States)

Siu, Ho Chit; Shah, Julie A.; Stirling, Leia A.

2016-01-01

Surface electromyography (sEMG) is a technique for recording natural muscle activation signals, which can serve as control inputs for exoskeletons and prosthetic devices. Previous experiments have incorporated these signals using both classical and pattern-recognition control methods in order to actuate such devices. We used the results of an experiment incorporating grasp and release actions with object contact to develop an intent-recognition system based on Gaussian mixture models (GMM) and continuous-emission hidden Markov models (HMM) of sEMG data. We tested this system with data collected from 16 individuals using a forearm band with distributed sEMG sensors. The data contain trials with shifted band alignments to assess robustness to sensor placement. This study evaluated and found that pattern-recognition-based methods could classify transient anticipatory sEMG signals in the presence of shifted sensor placement and object contact. With the best-performing classifier, the effect of label lengths in the training data was also examined. A mean classification accuracy of 75.96% was achieved through a unigram HMM method with five mixture components. Classification accuracy on different sub-movements was found to be limited by the length of the shortest sub-movement, which means that shorter sub-movements within dynamic sequences require larger training sets to be classified correctly. This classification of user intent is a potential control mechanism for a dynamic grasping task involving user contact with external objects and noise. Further work is required to test its performance as part of an exoskeleton controller, which involves contact with actuated external surfaces. PMID:27792155

One-Channel Surface Electromyography Decomposition for Muscle Force Estimation

Directory of Open Access Journals (Sweden)

Wentao Sun

2018-05-01

Full Text Available Estimating muscle force by surface electromyography (sEMG is a non-invasive and flexible way to diagnose biomechanical diseases and control assistive devices such as prosthetic hands. To estimate muscle force using sEMG, a supervised method is commonly adopted. This requires simultaneous recording of sEMG signals and muscle force measured by additional devices to tune the variables involved. However, recording the muscle force of the lost limb of an amputee is challenging, and the supervised method has limitations in this regard. Although the unsupervised method does not require muscle force recording, it suffers from low accuracy due to a lack of reference data. To achieve accurate and easy estimation of muscle force by the unsupervised method, we propose a decomposition of one-channel sEMG signals into constituent motor unit action potentials (MUAPs in two steps: (1 learning an orthogonal basis of sEMG signals through reconstruction independent component analysis; (2 extracting spike-like MUAPs from the basis vectors. Nine healthy subjects were recruited to evaluate the accuracy of the proposed approach in estimating muscle force of the biceps brachii. The results demonstrated that the proposed approach based on decomposed MUAPs explains more than 80% of the muscle force variability recorded at an arbitrary force level, while the conventional amplitude-based approach explains only 62.3% of this variability. With the proposed approach, we were also able to achieve grip force control of a prosthetic hand, which is one of the most important clinical applications of the unsupervised method. Experiments on two trans-radial amputees indicated that the proposed approach improves the performance of the prosthetic hand in grasping everyday objects.

Estimation of the neural drive to the muscle from surface electromyograms

Science.gov (United States)

Hofmann, David

Muscle force is highly correlated with the standard deviation of the surface electromyogram (sEMG) produced by the active muscle. Correctly estimating this quantity of non-stationary sEMG and understanding its relation to neural drive and muscle force is of paramount importance. The single constituents of the sEMG are called motor unit action potentials whose biphasic amplitude can interfere (named amplitude cancellation), potentially affecting the standard deviation (Keenan etal. 2005). However, when certain conditions are met the Campbell-Hardy theorem suggests that amplitude cancellation does not affect the standard deviation. By simulation of the sEMG, we verify the applicability of this theorem to myoelectric signals and investigate deviations from its conditions to obtain a more realistic setting. We find no difference in estimated standard deviation with and without interference, standing in stark contrast to previous results (Keenan etal. 2008, Farina etal. 2010). Furthermore, since the theorem provides us with the functional relationship between standard deviation and neural drive we conclude that complex methods based on high density electrode arrays and blind source separation might not bear substantial advantages for neural drive estimation (Farina and Holobar 2016). Funded by NIH Grant Number 1 R01 EB022872 and NSF Grant Number 1208126.

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.

Exercise muscle fatigue detection system implementation via wireless surface electromyography and empirical mode decomposition.

Science.gov (United States)

Chang, Kang-Ming; Liu, Shing-Hong; Wang, Jia-Jung; Cheng, Da-Chuan

2013-01-01

Surface electromyography (sEMG) is an important measurement for monitoring exercise and fitness. A wireless Bluetooth transmission sEMG measurement system with a sampling frequency of 2 KHz is developed. 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. As fatigue increases, the power spectrum of the sEMG shifts toward lower frequencies. The goal of this study is to evaluate the sensitivity of empirical mode decomposition (EMD) quantifying the electrical manifestations of the local muscle fatigue during exercising in health people. We also compared this method with the raw data and discrete wavelet transform (DWT). Five male and five female volunteers participated. Each subject was asked to run on a multifunctional pedaled elliptical trainer for about 30 minutes, twice a week, and there were a total of six recording times for each subject with a wireless EMG recording system. The results show that sensitivity of the highest frequency component of EMD is better than the highest frequency component of DWT, and raw data.

ELECTROMYOGRAPHIC EVALUATION OF MASTICATION AND SWALLOWING IN ELDERLY INDIVIDUALS WITH MANDIBULAR FIXED IMPLANTSUPPORTED PROSTHESES

Science.gov (United States)

Berretin-Felix, Giédre; Nary, Hugo; Padovani, Carlos Roberto; Trindade, Alceu Sergio; Machado, Wellington Monteiro

2008-01-01

This study evaluated the effect of implant-supported oral rehabilitation in the mandible on the electromyographic activity during mastication and swallowing in edentulous elderly individuals. Fifteen patients aged more than 60 years were evaluated, being 10 females and 5 males. All patients were edentulous, wore removable complete dentures on both dental arches, and had the mandibular dentures replaced by implant-supported prostheses. All patients were submitted to electromyographic evaluation of the masseter, superior orbicularis oris muscles, and the submental muscles, before surgery and 3, 6 and 18 months postoperatively, using foods of different textures. The results obtained at the different periods were analyzed statistically by Kruskal-Wallis non-parametric test. Statistical analysis showed that only the masseter muscle had a significant loss in electromyographic activity (p<0.001), with a tendency of similar response for the submental muscles. Moreover, there was an increase in the activity of the orbicularis oris muscle during rubber chewing after treatment, yet without statistically significant difference. Mandibular fixed implant-supported prostheses in elderly individuals revealed a decrease in electromyographic amplitude for the masseter muscles during swallowing, which may indicate adaptation to new conditions of stability provided by fixation of the complete denture in the mandibular arch. PMID:19089202

A novel approach for SEMG signal classification with adaptive local binary patterns.

Science.gov (United States)

Ertuğrul, Ömer Faruk; Kaya, Yılmaz; Tekin, Ramazan

2016-07-01

Feature extraction plays a major role in the pattern recognition process, and this paper presents a novel feature extraction approach, adaptive local binary pattern (aLBP). aLBP is built on the local binary pattern (LBP), which is an image processing method, and one-dimensional local binary pattern (1D-LBP). In LBP, each pixel is compared with its neighbors. Similarly, in 1D-LBP, each data in the raw is judged against its neighbors. 1D-LBP extracts feature based on local changes in the signal. Therefore, it has high a potential to be employed in medical purposes. Since, each action or abnormality, which is recorded in SEMG signals, has its own pattern, and via the 1D-LBP these (hidden) patterns may be detected. But, the positions of the neighbors in 1D-LBP are constant depending on the position of the data in the raw. Also, both LBP and 1D-LBP are very sensitive to noise. Therefore, its capacity in detecting hidden patterns is limited. To overcome these drawbacks, aLBP was proposed. In aLBP, the positions of the neighbors and their values can be assigned adaptively via the down-sampling and the smoothing coefficients. Therefore, the potential to detect (hidden) patterns, which may express an illness or an action, is really increased. To validate the proposed feature extraction approach, two different datasets were employed. Achieved accuracies by the proposed approach were higher than obtained results by employed popular feature extraction approaches and the reported results in the literature. Obtained accuracy results were brought out that the proposed method can be employed to investigate SEMG signals. In summary, this work attempts to develop an adaptive feature extraction scheme that can be utilized for extracting features from local changes in different categories of time-varying signals.

Effect of age and gender on the surface electromyogram during various levels of isometric contraction.

Science.gov (United States)

Arjunan, Sridhar; Kumar, Dinesh; Kalra, Chandan; Burne, John; Bastos, Teodiano

2011-01-01

This study reports the effects of age and gender on the surface electromyogram while performing isometric contraction. Experiments were conducted with two age groups--Young (Age: 20-29) and Old (Age: 60-69) where they performed sustained isometric contractions at various force levels (50%, 75%, 100% of maximum voluntary contraction). Traditional features such as root mean square (RMS) and median frequency (MDF) were computed from the recorded sEMG. The result indicates that the MDF of sEMG was not significantly affected by age, but was impacted by gender in both age groups. Also there was a significant change in the RMS of sEMG with age and gender at all levels of contraction. The results also indicate a large inter-subject variation. This study will provide an understanding of the underlying physiological effects of muscle contraction and muscle fatigue in different cohorts.

Oral-motor and electromyographic characterization of patients submitted to open a nd closed reductions of mandibular condyle fracture.

Science.gov (United States)

Silva, Amanda Pagliotto da; Sassi, Fernanda Chiarion; Andrade, Claudia Regina Furquim de

To characterize the oral-motor system of adults with mandibular condyle facture comparing the performance of individuals submitted to open reduction with internal fixation (ORIF) and closed reduction with mandibulomaxillary fixation (CRMMF). Study participants were 26 adults divided into three groups: G1 - eight individuals submitted to ORIF for correction of condyle fracture; G2 - nine individuals submitted to CRMMF for correction of condyle fracture; CG - nine healthy volunteers with no alterations of the orofacial myofunctional system. All participants underwent the same clinical protocol: assessment of the orofacial myofunctional system; evaluation of the mandibular range of motion; and surface electromyography (sEMG) of the masticatory muscles. Results indicated that patients with condyle fractures from both groups presented significant differences compared with those from the control group in terms of mobility of the oral-motor organs, mastication, and deglutition. Regarding the measures obtained for mandibular movements, participants with facial fractures from both groups showed significant differences compared with those from the control group, indicating greater restrictions in mandibular motion. As for the analysis of sEMG results, G1 patients presented more symmetrical masseter activation during the task of maximal voluntary teeth clenching. Patients with mandibular condyle fractures present significant deficits in posture, mobility, and function of the oral-motor system. The type of medical treatment does not influence the results of muscle function during the first six months after fracture reduction. Individuals submitted to ORIF of the condyle fracture present more symmetrical activation of the masseter muscle.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors.

Science.gov (United States)

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2010-10-21

Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

Directory of Open Access Journals (Sweden)

Kumar Dinesh

2010-10-01

Full Text Available Abstract Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS, Mean absolute value (MAV, Variance (VAR and Waveform length (WL and the proposed fractal features: fractal dimension (FD and maximum fractal length (MFL were computed. Multi-variant analysis of variance (MANOVA was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination

Myoeletric indices of fatigue adopting different rest intervals during leg press sets.

Science.gov (United States)

Miranda, Humberto; Maia, Marianna; de Oliveira, Carlos G; Farias, Déborah; da Silva, Jurandir B; Lima, Vicente P; Willardson, Jeffrey M; Paz, Gabriel A

2018-01-01

The purpose of this study was to examine the acute effect of different rest intervals between multiple sets of the 45° angled leg press exercise (LP45) on surface electromyographic (SEMG) spectral and amplitude indices of fatigue. Fifteen recreationally trained females performed three protocols in a randomized crossover design; each consisting of four sets of 10 repetitions with 1 (P1), 3 (P3), or 5 (P5) minute rest intervals between sets. Each set was performed with 70% of the LP45 ten-repetition maximum load. The SEMG data for biceps femoris (BF), vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles was then evaluated. The SEMG amplitude change in the time coefficient (CRMS) and spectral fatigue index (Cf5) indicated higher levels of fatigue for all muscles evaluated during the P3 protocol versus the P1 and P5 protocols (p ≤ 0.05), respectively. The RF and VL muscles showed greater fatigue levels by the second and third sets; whereas, greater fatigue was shown in the VM and BF muscles by the fourth set (p ≤ 0.05). A three-minute rest interval between sets might represent a neuromuscular window between a fatigue stated and fully recovered state in the context of neural activation. Moreover, a three minute rest interval between sets might allow for consistent recruitment of high threshold motor units over multiple sets, and thus promote a more effective stimulus for strength gains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of Exercise Order on Electromyographic Activity During Upper Body Resistance Training

Directory of Open Access Journals (Sweden)

Soncin Rafael

2014-12-01

Full Text Available The purpose of this study was to investigate the effects of exercise order on electromyographic activity in different muscle groups among youth men with experience in strength training. Three sets of 8 RM were performed of each exercise in two sequences order: (a sequence A: bench press, chest fly, shoulder press, shoulder abduction, close grip bench press and lying triceps extension; (b sequence B: the opposite order. The electromyographic activity was analyzed in the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii, normalized for maximal voluntary isometric contraction. The muscles activity of the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii showed significant interaction between sequence and exercise. The sternocostal head of the pectoralis major showed considerably higher activity in sequence A (100.13 ± 13.56% than sequence B (81.47 ± 13.09% for the chest fly. The anterior deltoid showed significantly higher electromyographic activity in sequence B (86.81 ± 40.43% than sequence A (66.15 ± 22.02% for the chest fly, whereas for the lying triceps extension, the electromyographic activity was significantly higher in sequence A (53.89 ± 27.09% than sequence B (34.32 ± 23.70%. For the long head triceps brachii, only the shoulder press showed differences between sequences (A = 52.43 ± 14.64 vs. B = 38.53 ± 16.26. The present study showed that the exercise order could modify the training results even though there was no alteration in volume and intensity of the exercise. These changes may result in different training adaptations.

Relationship between lower limb position and pelvic floor muscle surface electromyography activity in menopausal women: a prospective observational study

Directory of Open Access Journals (Sweden)

Halski T

2017-01-01

Full Text Available Tomasz Halski,1 Kuba Ptaszkowski,2 Lucyna Słupska,1 Robert Dymarek,3 Małgorzata Paprocka-Borowicz2 1Department of Physiotherapy, Opole Medical School, Opole, 2Department of Clinical Biomechanics and Physiotherapy in Motor System Disorders, 3Department of Nervous System Diseases, Faculty of Health Science, Wroclaw Medical University, Wroclaw, Poland Objectives: In physiotherapeutic practice, special attention is being given to the reciprocal anatomical, physiological, and biomechanical relationship of the pelvis and the structures connected to it. However, the scientific literature shows mainly the theoretical information about their mutual connections. The lack of information about these relations from a practical aspect coupled with the paucity of scientific papers on the impact of posture changes on the pelvic floor led the authors to conduct this study. The primary aim of this study was to compare the resting and functional bioelectrical activities of pelvic floor muscles (PFMs depending on three different positions of the lower limbs (positions A, B, and C in the supine position.Materials and methods: This was a prospective observational study evaluating resting and functional activities of the PFM depending on the position of the lower limbs. The study was carried out at the Department and Clinic of Urology, University Hospital in Wroclaw, Poland and the target group were women in the menopausal period. Bioelectrical activity of PFM was recorded using a surface electromyographic instrument in the supine position. Results of the values obtained in A, B, and C positions were compared using a one-way analysis of variance.Results: In position A, the average resting surface electromyography (sEMG activity of PFM was 6.9±2.6 µV; in position B, the result was 6.9±2.5 µV and in position C, the resting sEMG activity was 5.7±1.8 µV (P=0.0102. The results of the functional bioelectrical activity of PFM were as follows: position A – 20.3�

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.

Motor unit number index (MUNIX) derivation from the relationship between the area and power of surface electromyogram: a computer simulation and clinical study

Science.gov (United States)

Miralles, Francesc

2018-06-01

Objective. The motor unit number index (MUNIX) is a technique based on the surface electromyogram (sEMG) that is gaining acceptance as a method for monitoring motor neuron loss, because it is reliable and produces less discomfort than other electrodiagnostic techniques having the same intended purpose. MUNIX assumes that the relationship between the area of sEMG obtained at increasing levels of muscle activation and the values of a variable called ‘ideal case motor unit count’ (ICMUC), defined as the product of the ratio between area and power of the compound muscle action potential (CMAP) by that of the sEMG, is described by a decreasing power function. Nevertheless, the reason for this comportment is unknown. The objective of this work is to investigate if the definition of MUNIX could derive from more basic properties of the sEMG. Approach. The CMAP and sEMG epochs obtained at different levels of muscle activation from (1) the abductor pollicis brevis (APB) muscle of persons with and without a carpal tunnel syndrome (CTS) and (2) from a computer model of sEMG generation previously published were analysed. Main results. MUNIX reflects the power relationship existing between the area and power of a sEMG. The exponent of this function was smaller in patients with motor CTS than in the rest of the subjects. The analysis of the relationship between the area and power of a sEMG could aid in distinguishing a MUNIX reduction due to a motoneuron loss from that due to a loss of muscle fibre. Significance. MUNIX is derived from the relationship between the area and power of a sEMG. This relationship changes when there is a loss of motor units (MUs), which partially explains the diagnostic sensibility of MUNIX. Although the reasons for this change are unknown, it could reflect an increase in the proportion of MUs of great amplitude.

Validity and Reliability of Surface Electromyography Measurements from a Wearable Athlete Performance System

Directory of Open Access Journals (Sweden)

Scott K. Lynn, Casey M. Watkins, Megan A. Wong, Katherine Balfany, Daniel F. Feeney

2018-06-01

Full Text Available The Athos ® wearable system integrates surface electromyography (sEMG electrodes into the construction of compression athletic apparel. The Athos system reduces the complexity and increases the portability of collecting EMG data and provides processed data to the end user. The objective of the study was to determine the reliability and validity of Athos as compared with a research grade sEMG system. Twelve healthy subjects performed 7 trials on separate days (1 baseline trial and 6 repeated trials. In each trial subjects wore the wearable sEMG system and had a research grade sEMG system’s electrodes placed just distal on the same muscle, as close as possible to the wearable system’s electrodes. The muscles tested were the vastus lateralis (VL, vastus medialis (VM, and biceps femoris (BF. All testing was done on an isokinetic dynamometer. Baseline testing involved performing isometric 1 repetition maximum tests for the knee extensors and flexors and three repetitions of concentric-concentric knee flexion and extension at MVC for each testing speed: 60, 180, and 300 deg/sec. Repeated trials 2-7 each comprised 9 sets where each set included three repetitions of concentric-concentric knee flexion-extension. Each repeated trial (2-7 comprised one set at each speed and percent MVC (50%, 75%, 100% combination. The wearable system and research grade sEMG data were processed using the same methods and aligned in time. The amplitude metrics calculated from the sEMG for each repetition were the peak amplitude, sum of the linear envelope, and 95th percentile. Validity results comprise two main findings. First, there is not a significant effect of system (Athos or research grade system on the repetition amplitude metrics (95%, peak, or sum. Second, the relationship between torque and sEMG is not significantly different between Athos and the research grade system. For reliability testing, the variation across trials and averaged across speeds was 0.8%, 7

Electromyographic evaluation of mastication and swallowing in elderly individuals with mandibular fixed implant-supported prostheses

Directory of Open Access Journals (Sweden)

Giédre Berretin-Felix

2008-04-01

Full Text Available This study evaluated the effect of implant-supported oral rehabilitation in the mandible on the electromyographic activity during mastication and swallowing in edentulous elderly individuals. Fifteen patients aged more than 60 years were evaluated, being 10 females and 5 males. All patients were edentulous, wore removable complete dentures on both dental arches, and had the mandibular dentures replaced by implant-supported prostheses. All patients were submitted to electromyographic evaluation of the masseter, superior orbicularis oris muscles, and the submental muscles, before surgery and 3, 6 and 18 months postoperatively, using foods of different textures. The results obtained at the different periods were analyzed statistically by Kruskal-Wallis non-parametric test. Statistical analysis showed that only the masseter muscle had a significant loss in electromyographic activity (p<0.001, with a tendency of similar response for the submental muscles. Moreover, there was an increase in the activity of the orbicularis oris muscle during rubber chewing after treatment, yet without statistically significant difference. Mandibular fixed implant-supported prostheses in elderly individuals revealed a decrease in electromyographic amplitude for the masseter muscles during swallowing, which may indicate adaptation to new conditions of stability provided by fixation of the complete denture in the mandibular arch.

Integration of active pauses and pattern of muscular activity during computer work.

Science.gov (United States)

St-Onge, Nancy; Samani, Afshin; Madeleine, Pascal

2017-09-01

Submaximal isometric muscle contractions have been reported to increase variability of muscle activation during computer work; however, other types of active contractions may be more beneficial. Our objective was to determine which type of active pause vs. rest is more efficient in changing muscle activity pattern during a computer task. Asymptomatic regular computer users performed a standardised 20-min computer task four times, integrating a different type of pause: sub-maximal isometric contraction, dynamic contraction, postural exercise and rest. Surface electromyographic (SEMG) activity was recorded bilaterally from five neck/shoulder muscles. Root-mean-square decreased with isometric pauses in the cervical paraspinals, upper trapezius and middle trapezius, whereas it increased with rest. Variability in the pattern of muscular activity was not affected by any type of pause. Overall, no detrimental effects on the level of SEMG during active pauses were found suggesting that they could be implemented without a cost on activation level or variability. Practitioner Summary: We aimed to determine which type of active pause vs. rest is best in changing muscle activity pattern during a computer task. Asymptomatic computer users performed a standardised computer task integrating different types of pauses. Muscle activation decreased with isometric pauses in neck/shoulder muscles, suggesting their implementation during computer work.

Dynamical Coordination of Hand Intrinsic Muscles for Precision Grip in Diabetes Mellitus.

Science.gov (United States)

Li, Ke; Wei, Na; Cheng, Mei; Hou, Xingguo; Song, Jun

2018-03-12

This study investigated the effects of diabetes mellitus (DM) on dynamical coordination of hand intrinsic muscles during precision grip. Precision grip was tested using a custom designed apparatus with stable and unstable loads, during which the surface electromyographic (sEMG) signals of the abductor pollicis brevis (APB) and first dorsal interosseous (FDI) were recorded simultaneously. Recurrence quantification analysis (RQA) was applied to quantify the dynamical structure of sEMG signals of the APB and FDI; and cross recurrence quantification analysis (CRQA) was used to assess the intermuscular coupling between the two intrinsic muscles. This study revealed that the DM altered the dynamical structure of muscle activation for the FDI and the dynamical intermuscular coordination between the APB and FDI during precision grip. A reinforced feedforward mechanism that compensates the loss of sensory feedbacks in DM may be responsible for the stronger intermuscular coupling between the APB and FDI muscles. Sensory deficits in DM remarkably decreased the capacity of online motor adjustment based on sensory feedback, rendering a lower adaptability to the uncertainty of environment. This study shed light on inherent dynamical properties underlying the intrinsic muscle activation and intermuscular coordination for precision grip and the effects of DM on hand sensorimotor function.

Abnormal electromyographic activity of the urethral sphincter, voiding dysfunction, and polycystic ovaries: a new syndrome?

OpenAIRE

Fowler, C. J.; Christmas, T. J.; Chapple, C. R.; Parkhouse, H. F.; Kirby, R. S.; Jacobs, H. S.

1988-01-01

A potential association between abnormal electromyographic activity--that is, decelerating bursts and complex repetitive discharges--of the urethral sphincter and difficulty in voiding was examined in 57 women with urinary retention. Abnormal electromyographic activity was found in 33. Ultrasonography of the ovaries in 22 of the 33 women showed that 14 had polycystic ovaries. Of the other eight women, two had had oophorectomies, one had shrunken ovaries and ovarian failure, and one had previo...

Muscle conduction velocity, surface electromyography variables, and echo intensity during concentric and eccentric fatigue.

Science.gov (United States)

Gonzalez-Izal, Miriam; Lusa Cadore, Eduardo; Izquierdo, Mikel

2014-03-01

Concentric (CON) and eccentric (ECC) contractions may involve different mechanisms related to changes in sarcolemma status and the consequent alteration of action potential transmission along muscle fibers. Muscle conduction velocity (CV), surface electromyography signal (sEMG), muscle quality, and blood lactate concentrations were analyzed during CON and ECC actions. Compared with ECC, the CON protocol resulted in greater muscle force losses, blood lactate concentrations, and changes in sEMG parameters. Similar reductions in CV were detected in both protocols. Higher echo intensity values were observed 2 days after ECC due to greater muscle damage. The effects of the muscle damage produced by ECC exercise on the transmission of action potentials along muscle fibers (measured as the CV) may be comparable with the effects of hydrogen accumulation produced by CON exercise (related to greater lactate concentrations), which causes greater force loss and change in other sEMG variables during CON than during ECC actions.

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.

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.

Detecting and Predicting Muscle Fatigue during Typing By SEMG Signal Processing and Artificial Neural Networks

Directory of Open Access Journals (Sweden)

Elham Ghoochani

2011-03-01

Full Text Available Introduction: Repetitive strain injuries are one of the most prevalent problems in occupational diseases. Repetition, vibration and bad postures of the extremities are physical risk factors related to work that can cause chronic musculoskeletal disorders. Repetitive work on a computer with low level contraction requires the posture to be maintained for a long time, which can cause muscle fatigue. Muscle fatigue in shoulders and neck is one of the most prevalent problems reported with computer users especially during typing. Surface electromyography (SEMG signals are used for detecting muscle fatigue as a non-invasive method. Material and Methods: Nine healthy females volunteered for signal recoding during typing. EMG signals were recorded from the trapezius muscle, which is subjected to muscle fatigue during typing.  After signal analysis and feature extraction, detecting and predicting muscle fatigue was performed by using the MLP artificial neural network. Results: Recorded signals were analyzed in time and frequency domains for feature extraction. Results of classification showed that the MLP neural network can detect and predict muscle fatigue during typing with 80.79 % ± 1.04% accuracy. Conclusion: Intelligent classification and prediction of muscle fatigue can have many applications in human factors engineering (ergonomics, rehabilitation engineering and biofeedback equipment for mitigating the injuries of repetitive works.

Electromyographic analysis of exercise resulting in symptoms of muscle damage.

Science.gov (United States)

McHugh, M P; Connolly, D A; Eston, R G; Gleim, G W

2000-03-01

Surface electromyographic (EMG) signals were recorded from the hamstring muscles during six sets of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions. The EMG per unit torque increased during eccentric (P exercise. Similarly, the median frequency increased during eccentric (P exercise. The EMG per unit torque was lower for submaximal eccentric than maximum isometric contractions (P unit torque was lower for eccentric than concentric contractions (P exercise resulted in significant isometric strength loss (P exercise, while the most severe pain and muscle tenderness occurred 2 days after eccentric exercise. A lower EMG per unit torque is consistent with the selective recruitment of a small number of motor units during eccentric exercise. A higher median frequency during eccentric contractions may be explained by selective recruitment of fast-twitch motor units. The present results are consistent with the theory that muscle damage results from excessive stress on a small number of active fibres during eccentric contractions.

Limitations of Spectral Electromyogramic Analysis to Determine the Onset of Neuromuscular Fatigue Threshold during Incremental Ergometer Cycling

Directory of Open Access Journals (Sweden)

Iban Latasa, Alfredo Cordova, Armando Malanda, Javier Navallas, Ana Lavilla-Oiz, Javier Rodriguez-Falces

2016-03-01

Full Text Available Recently, a new method has been proposed to detect the onset of neuromuscular fatigue during an incremental cycling test by assessing the changes in spectral electromyographic (sEMG frequencies within individual exercise periods of the test. The method consists on determining the highest power output that can be sustained without a significant decrease in spectral frequencies. This study evaluated the validity of the new approach by assessing the changes in spectral indicators both throughout the whole test and within individual exercise periods of the test. Fourteen cyclists performed incremental cycle ergometer rides to exhaustion with bipolar surface EMG signals recorded from the vastus lateralis. The mean and median frequencies (Fmean and Fmedian, respectively of the sEMG power spectrum were calculated. The main findings were: (1 Examination of spectral indicators within individual exercise periods of the test showed that neither Fmean nor Fmedian decreased significantly during the last (most fatiguing exercise periods. (2 Examination of the whole incremental test showed that the behaviour of Fmean and Fmedian with increasing power output was highly inconsistent and varied greatly among subjects. (3 Over the whole incremental test, half of the participants exhibited a positive relation between spectral indicators and workload, whereas the other half demonstrated the opposite behavior. Collectively, these findings indicate that spectral sEMG indexes do not provide a reliable measure of the fatigue state of the muscle during an incremental cycling test. Moreover, it is concluded that it is not possible to determine the onset of neuromuscular fatigue during an incremental cycling test by examining spectral indicators within individual exercise periods of the test.

Relationship among vaginal palpation, vaginal squeeze pressure, electromyographic and ultrasonographic variables of female pelvic floor muscles

Directory of Open Access Journals (Sweden)

Vanessa S. Pereira

2014-10-01

Full Text Available Background: The proper evaluation of the pelvic floor muscles (PFM is essential for choosing the correct treatment. Currently, there is no gold standard for the assessment of female PFM function. Objective: To determine the correlation between vaginal palpation, vaginal squeeze pressure, and electromyographic and ultrasonographic variables of the female PFM. Method: This cross-sectional study evaluated 80 women between 18 and 35 years of age who were nulliparous and had no pelvic floor dysfunction. PFM function was assessed based on digital palpation, vaginal squeeze pressure, electromyographic activity, bilateral diameter of the bulbocavernosus muscles and the amount of bladder neck movement during voluntary PFM contraction using transperineal bi-dimensional ultrasound. The Pearson correlation was used for statistical analysis (p<0.05. Results: There was a strong positive correlation between PFM function and PFM contraction pressure (0.90. In addition, there was a moderate positive correlation between these two variables and PFM electromyographic activity (0.59 and 0.63, respectively and movement of the bladder neck in relation to the pubic symphysis (0.51 and 0.60, respectively. Conclusions: This study showed that there was a correlation between vaginal palpation, vaginal squeeze pressure, and electromyographic and ultrasonographic variables of the PFM in nulliparous women. The strong correlation between digital palpation and PFM contraction pressure indicated that perineometry could easily be replaced by PFM digital palpation in the absence of equipment.

Electromyographic Comparison of Squats Using Constant or Variable Resistance.

Science.gov (United States)

Andersen, Vidar; Steiro Fimland, Marius; Knutson Kolnes, Maria; Jensen, Susanne; Laume, Martine; Hole Saeterbakken, Atle

2016-12-01

Andersen, V, Fimland, MS, Kolnes, MK, Jensen, S, Laume, M and Saeterbakken, AH. Electromyographic comparison of squats using constant or variable resistance. J Strength Cond Res 30(12): 3456-3463, 2016-The aim of the study was to compare the electromyographic (EMG) activity of vastus lateralis, vastus medialis, rectus femoris, and biceps femoris when performing the squat with constant resistance or variable resistance with 2 or 4 elastic bands, respectively, contributing with a mean of 39 and 73% of the total loads. Nineteen resistance-trained women performed 6 repetition maximum using 3 different experimental conditions: free weights (FW), free weights + 2 elastic bands (FW + 2EB), and free weights + 4 elastic bands (FW + 4EB). During analyses, each repetition was divided into 6 phases: upper (more extended knee), middle, and lower phase of the descending and ascending movements. Increased activation in the upper parts of the movement was observed for both variable resistance conditions compared with constant resistance (9-51%, p squat using free weights in combination with elastic bands seems to be preferable compared with free weights alone and more so with a high contribution from variable resistance to the total load.

Electromyographical Comparison of a Traditional, Suspension Device, and Towel Pull-Up

Directory of Open Access Journals (Sweden)

Snarr Ronald L.

2017-08-01

Full Text Available Strengthening muscles of the back may have various implications for improving functions of daily living, aiding in the transfer of power in throwing, and assist in injury prevention of the shoulder complex. While several versions of the pull-up exist, there is currently no literature comparing their differences. The purpose of this investigation was to compare the electromyographical activity of the latissimus dorsi, posterior deltoid, middle trapezius, and biceps brachii while performing three variations of the pull-up. Resistance-trained men and women (n =15, age = 24.87 ± 6.52 years participated in this study by performing traditional pull-ups, suspension device pull-ups, and towel pull-ups in a randomized fashion. Each pull-up was performed for three repetitions with a 1.5 bi-acromial grip-width for each participant. Normalized (%MVC electromyographical values were recorded for each muscle group during each pull-up variation. No significant differences existed within the latissimus dorsi, biceps brachii or posterior deltoid between any of the exercises. For the middle trapezius, towel pull-ups provided significantly lower muscle activity than the traditional pull-up, while no differences between suspension pull-ups and the other variations occurred. In conclusion, only one muscular difference existed between the exercise variations and all versions examined provided electromyographical values, determined by current literature, to invoke a sufficient stimulus to promote increases in muscle strength and hypertrophy. Although further research is needed, practitioners can be confident when programming any of the movement variations examined when attempting to elicit adaptations of muscular strength and hypertrophy.

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.

Validity and Reliability of Surface Electromyography in the Assessment of Primary Muscle Tension Dysphonia.

Science.gov (United States)

Khoddami, Seyyedeh Maryam; Talebian, Saeed; Izadi, Farzad; Ansari, Noureddin Nakhostin

2017-05-01

The study aims to evaluate the reliability and the discriminative validity of surface electromyography (sEMG) in the assessment of patients with primary muscle tension dysphonia (MTD). The study design is cross-sectional. Fifteen patients with primary MTD (mean age: 34.07 ± 10.99 years) and 15 healthy volunteers (mean age: 34.53 ± 10.63 years) were included. All participants underwent evaluation of sEMG to record the electrical activity of the thyrohyoid and cricothyroid muscles. The outcome measures were the root mean square (RMS), activity peak, duration, and time to the peak activity, which were obtained during /a/ and /i/ prolongation for test-retest reliability. The test-retest reliability was good to excellent for the RMS and peak activity measures (intraclass correlation coefficient [agreement] [ICC agreement ] = 0.49-0.98). The reliability for the activity duration was poor to excellent (ICC agreement  = 0.19-0.9). Poor test-retest reliability was found for the time to peak measure (ICC agreement  = 0.15-0.37). The standard error of measurement for all sEMG measures was between 0.41 and 2.05. The smallest detectable change (SDC) was calculated between 1.13 and 5.66. The highest SDC values were obtained for the peak and the lowest SDCs were documented for the duration (5.66 and 1.13, respectively). All sEMG measures were not able to discriminate between the MTD patients and healthy subjects (P > 0.05). The sEMG is a reliable tool to measure the RMS, the peak activity, and the activity duration in primary MTD. However, it is not able to discriminate the patients with primary MTD from healthy subjects. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Latent Factors Limiting the Performance of sEMG-Interfaces

Directory of Open Access Journals (Sweden)

Sergey Lobov

2018-04-01

Full Text Available Recent advances in recording and real-time analysis of surface electromyographic signals (sEMG have fostered the use of sEMG human–machine interfaces for controlling personal computers, prostheses of upper limbs, and exoskeletons among others. Despite a relatively high mean performance, sEMG-interfaces still exhibit strong variance in the fidelity of gesture recognition among different users. Here, we systematically study the latent factors determining the performance of sEMG-interfaces in synthetic tests and in an arcade game. We show that the degree of muscle cooperation and the amount of the body fatty tissue are the decisive factors in synthetic tests. Our data suggest that these factors can only be adjusted by long-term training, which promotes fine-tuning of low-level neural circuits driving the muscles. Short-term training has no effect on synthetic tests, but significantly increases the game scoring. This implies that it works at a higher decision-making level, not relevant for synthetic gestures. We propose a procedure that enables quantification of the gestures’ fidelity in a dynamic gaming environment. For each individual subject, the approach allows identifying “problematic” gestures that decrease gaming performance. This information can be used for optimizing the training strategy and for adapting the signal processing algorithms to individual users, which could be a way for a qualitative leap in the development of future sEMG-interfaces.

Normal paraspinal muscle electromyographic fatigue characteristics in patients with primary fibromyalgia.

Science.gov (United States)

Stokes, M J; Colter, C; Klestov, A; Cooper, R G

1993-08-01

Paraspinal muscle fatigue mechanisms were compared in 14 primary fibromyalgia patients and 14 age and sex matched normal subjects using a standardized 60-s isometric endurance test of the paraspinal muscles, during which surface integrated electromyographic (IEMG) activity was recorded. Fatigue-induced IEMG increases were similar for both groups during the initial 40 s (up to 112 +/- 20% and 111 +/- 6% of initial values in patients and normal subjects respectively). Thereafter, IEMG fell significantly in patients (P BMI, range 19-25 in controls) those with a BMI BMI > 26 (n = 9) showed greater IEMG declines after 40 s than either normal subjects or in the fibromyalgia group as a whole. Paraspinal muscle fatigue mechanisms appear normal in primary fibromyalgia patients. Isometric force maintenance in overweight patients, despite IEMG declines, illustrates the action of intrinsic fatigue resistance mechanisms which were presumably utilized to a greater extent in these patients to cope with the extra load.

Gender variability in electromyographic activity, in vivo behaviour of the human gastrocnemius and mechanical capacity during the take-off phase of a countermovement jump.

Science.gov (United States)

Rubio-Arias, Jacobo Ángel; Ramos-Campo, Domingo Jesús; Peña Amaro, José; Esteban, Paula; Mendizábal, Susana; Jiménez, José Fernando

2017-11-01

The purpose of this study was to analyse gender differences in neuromuscular behaviour of the gastrocnemius and vastus lateralis during the take-off phase of a countermovement jump (CMJ), using direct measures (ground reaction forces, muscle activity and dynamic ultrasound). Sixty-four young adults (aged 18-25 years) participated voluntarily in this study, 35 men and 29 women. The firing of the trigger allowed obtainment of data collection vertical ground reaction forces (GRF), surface electromyography activity (sEMG) and dynamic ultrasound gastrocnemius of both legs. Statistically significant gender differences were observed in the jump performance, which appear to be based on differences in muscle architecture and the electrical activation of the gastrocnemius muscles and vastus lateralis. So while men developed greater peak power, velocity take-offs and jump heights, jump kinetics compared to women, women also required a higher electrical activity to develop lower power values. Additionally, the men had higher values pennation angles and muscle thickness than women. Men show higher performance of the jump test than women, due to significant statistical differences in the values of muscle architecture (pennation angle and thickness muscle), lower Neural Efficiency Index and a higher amount of sEMG activity per second during the take-off phase of a CMJ. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Interacting proteins on human spermatozoa: adaptive evolution of the binding of semenogelin I to EPPIN.

Directory of Open Access Journals (Sweden)

Erick J R Silva

Full Text Available Semenogelin I (SEMG1 is found in human semen coagulum and on the surface of spermatozoa bound to EPPIN. The physiological significance of the SEMG1/EPPIN interaction on the surface of spermatozoa is its capacity to modulate sperm progressive motility. The present study investigates the hypothesis that the interacting surface of SEMG1 and EPPIN co-evolved within the Hominoidea time scale, as a result of adaptive pressures applied by their roles in sperm protection and reproductive fitness. Our results indicate that some amino acid residues of SEMG1 and EPPIN possess a remarkable deficiency of variation among hominoid primates. We observe a distinct residue change unique to humans within the EPPIN sequence containing a SEMG1 interacting surface, namely His92. In addition, Bayes Empirical Bayes analysis for positive selection indicates that the SEMG1 Cys239 residue underwent positive selection in humans, probably as a consequence of its role in increasing the binding affinity of these interacting proteins. We confirm the critical role of Cys239 residue for SEMG1 binding to EPPIN and inhibition of sperm motility by showing that recombinant SEMG1 mutants in which Cys239 residue was changed to glycine, aspartic acid, histidine, serine or arginine have reduced capacity to interact to EPPIN and to inhibit human sperm motility in vitro. In conclusion, our results indicate that EPPIN and SEMG1 rapidly co-evolved in primates due to their critical role in the modulation of sperm motility in the semen coagulum, providing unique insights into the molecular co-evolution of sperm surface interacting proteins.

Dexterous hand gestures recognition based on low-density sEMG signals for upper-limb forearm amputees

Directory of Open Access Journals (Sweden)

John Jairo Villarejo Mayor

2017-08-01

Full Text Available Abstract Introduction Intuitive prosthesis control is one of the most important challenges in order to reduce the user effort in learning how to use an artificial hand. This work presents the development of a novel method for pattern recognition of sEMG signals able to discriminate, in a very accurate way, dexterous hand and fingers movements using a reduced number of electrodes, which implies more confidence and usability for amputees. Methods The system was evaluated for ten forearm amputees and the results were compared with the performance of able-bodied subjects. Multiple sEMG features based on fractal analysis (detrended fluctuation analysis and Higuchi’s fractal dimension combined with traditional magnitude-based features were analyzed. Genetic algorithms and sequential forward selection were used to select the best set of features. Support vector machine (SVM, K-nearest neighbors (KNN and linear discriminant analysis (LDA were analyzed to classify individual finger flexion, hand gestures and different grasps using four electrodes, performing contractions in a natural way to accomplish these tasks. Statistical significance was computed for all the methods using different set of features, for both groups of subjects (able-bodied and amputees. Results The results showed average accuracy up to 99.2% for able-bodied subjects and 98.94% for amputees using SVM, followed very closely by KNN. However, KNN also produces a good performance, as it has a lower computational complexity, which implies an advantage for real-time applications. Conclusion The results show that the method proposed is promising for accurately controlling dexterous prosthetic hands, providing more functionality and better acceptance for amputees.

Electromyographic analysis of repeated bouts of eccentric exercise.

Science.gov (United States)

McHugh, M P; Connolly, D A; Eston, R G; Gartman, E J; Gleim, G W

2001-03-01

The repeated bout effect refers to the protective effect provided by a single bout of eccentric exercise against muscle damage from a similar subsequent bout. The aim of this study was to determine if the repeated bout was associated with an increase in motor unit activation relative to force production, an increased recruitment of slow-twitch motor units or increased motor unit synchronization. Surface electromyographic (EMG) signals were recorded from the hamstring muscles during two bouts of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions separated by 2 weeks. The EMG per unit torque and median frequency were analysed. The initial bout of eccentric exercise resulted in strength loss, pain and muscle tenderness, while the repeated eccentric bout resulted in a slight increase in strength, no pain and no muscle tenderness (bout x time effects, P exercise. The EMG per unit torque and median frequency were not different between the initial and repeated bouts of eccentric exercise. The EMG per unit torque and median frequency increased during both bouts of eccentric exercise (P < 0.01) but did not change during either concentric bout. In conclusion, there was no evidence that the repeated bout effect was due to a neural adaptation.

Effect of gender on strength gains after isometric exercise coupled with electromyographic biofeedback in knee osteoarthritis: a preliminary study.

Science.gov (United States)

Anwer, S; Equebal, A; Nezamuddin, M; Kumar, R; Lenka, P K

2013-09-01

The objective of this trial was to evaluate the effect of gender on strength gains after five week training programme that consisted of isometric exercise coupled with electromyographic biofeedback to the quadriceps muscle. Forty-three (20 men and 23 women) patients with knee osteoarthritis (OA), were placed into two groups based on their gender. Both groups performed isometric exercise coupled with electromyographic biofeedback for five days a week for five weeks. Both groups reported gains in muscle strength after five week training. However, the difference was found to be statistically insignificant between the two groups (P=0.224). The results suggest that gender did not affect gains in muscle strength by isometric exercise coupled with electromyographic biofeedback in patients with knee OA. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration

Science.gov (United States)

Arenas, Ana M.; Sun, Tingxiao

2018-01-01

Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG), but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue. PMID:29401754

Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration

Directory of Open Access Journals (Sweden)

Ho Chit Siu

2018-02-01

Full Text Available Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG, but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue.

Tennis players show a lower coactivation of the elbow antagonist muscles during isokinetic exercises.

Science.gov (United States)

Bazzucchi, Ilenia; Riccio, Maria Elena; Felici, Francesco

2008-10-01

Previous studies have suggested that muscle coactivation could be reduced by a recurrent activity (training, daily activities). If this was correct, skilled athletes should show a specific muscle activation pattern with a low level of coactivation of muscles which are typically involved in their discipline. In particular, the aim of this study was to verify the hypothesis that the amount of antagonist activation of biceps brachii (BB) and triceps brachii (TB) is different between tennis players and non-players individuals during maximal isokinetic contractions. Ten young healthy men and eight male tennis players participated in the study. The surface electromyographic signals (sEMG) were recorded from the BB and TB muscles during three maximal voluntary isometric contractions (MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions at 15 degrees , 30 degrees , 60 degrees , 120 degrees , 180 degrees and 240 degrees /s. Normalized root mean square (RMS) of sEMG was calculated as an index of sEMG amplitude. Antagonist activation (%RMSmax) of TB was significantly lower in tennis players (from 14.0+/-7.9% at MVC to 16.3+/-8.9% at 240 degrees /s) with respect to non-players (from 27.7+/-19.7% at MVC to 38.7+/-17.6% at 240 degrees /s) at all angular velocities. Contrary to non-players, tennis players did not show any difference in antagonist activation between BB and TB muscles. Tennis players, with a constant practice in controlling forces around the elbow joint, learn how to reduce coactivation of muscles involved in the control of this joint. This has been shown by the lower antagonist muscular activity of triceps brachii muscle during isokinetic elbow flexion found in tennis players with respect to non-players.

A cola-induced hypokalemic rhabdomyolysis with electromyographic evaluation: A case report

Directory of Open Access Journals (Sweden)

Davide Ferrazzoli

2017-02-01

Full Text Available Objective: To report a rare case of hypokalemic rhabdomyolysis induced by the heavy and prolonged ingestion of cola-based beverages, and its uneventful recovery after kalemia normalization. Methods: We report a 38-year-old Caucasian male presented in our emergency room with a recent and progressive weakness of the lower limbs proximal muscles. Results: A dietary history revealed a prolonged ingestion of cola-based beverages. Blood tests showed severe hypokalemia and marked increase in serum creatine phosphokinase. The analysis of cerebrospinal fluid resulted normal. Electromyography was suggestive for a myopathy. The clinical, laboratory and neurophysiological data were evocative for a cola-induced hypokalemic rhabdomyolysis. After kalemia normalization, the improvements of the electromyographic findings paralleled the clinical recovery. Conclusion: Chronic consumption of large amount of cola-based soft drinks may result in severe symptomatic hypokalemia, eventually leading in turn to myopathy. To our knowledge, this is the first description of the electromyographic findings of the cola-induced hypokalemic rhabdomyolysis. An early diagnosis and a prompt treatment appear to be crucial for a benign clinical course.

A cola-induced hypokalemic rhabdomyolysis with electromyographic evaluation: A case report.

Science.gov (United States)

Ferrazzoli, Davide; Sabetta, Annarita; Palamara, Grazia; Caremani, Luca; Capobianco, Marina; Balbi, Pietro; Frazzitta, Giuseppe

2017-01-01

To report a rare case of hypokalemic rhabdomyolysis induced by the heavy and prolonged ingestion of cola-based beverages, and its uneventful recovery after kalemia normalization. We report a 38-year-old Caucasian male presented in our emergency room with a recent and progressive weakness of the lower limbs proximal muscles. A dietary history revealed a prolonged ingestion of cola-based beverages. Blood tests showed severe hypokalemia and marked increase in serum creatine phosphokinase. The analysis of cerebrospinal fluid resulted normal. Electromyography was suggestive for a myopathy. The clinical, laboratory and neurophysiological data were evocative for a cola-induced hypokalemic rhabdomyolysis. After kalemia normalization, the improvements of the electromyographic findings paralleled the clinical recovery. Chronic consumption of large amount of cola-based soft drinks may result in severe symptomatic hypokalemia, eventually leading in turn to myopathy. To our knowledge, this is the first description of the electromyographic findings of the cola-induced hypokalemic rhabdomyolysis. An early diagnosis and a prompt treatment appear to be crucial for a benign clinical course.

Motor unit properties of biceps brachii in chronic stroke patients assessed with high-density surface EMG

NARCIS (Netherlands)

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

2009-01-01

The aim of this study was to investigate motor unit (MU) characteristics of the biceps brachii in post-stroke patients, using high-density surface electromyography (sEMG). Eighteen chronic hemiparetic stroke patients took part. The Fugl-Meyer score for the upper extremity was assessed. Subjects

Electromyographic analysis of the vertebral extensor muscles during the Biering-Sorensen Test

Directory of Open Access Journals (Sweden)

Ligia Moreira de Santana

2014-03-01

Full Text Available The purpose of the study was to analyze the electromyographic signal of the multifidus, longissimus thoracis and the lumbar iliocostalis muscles during the Biering-Sorensen test in subjects without lower back pain. Twenty volunteers performed the test on three separate occasions. An analysis of variance detected a difference between the three test times (p = 0.0026. For the frequency domain, it was observed that there were differences between the multifidus and the lumbar erectors muscles; longissimus and iliocostalis muscles. However, in the time domain analysis, no difference was observed. As the values of the slope coefficients of median frequencies were higher for the multifidus muscle, compared to the longissimus and lumbar iliocostalis muscles, this may indicate a higher tendency toward muscle fatigue. Therefore, considering the applied methodology, the study of electromyographic signals in the frequency domain should be considered as an instrument to assess fatigue of the spinal extensor muscles in clinical situations.

Effects of external pelvic compression on electromyographic activity of the hamstring muscles during unipedal stance in sportsmen with and without hamstring injuries.

Science.gov (United States)

Arumugam, Ashokan; Milosavljevic, Stephan; Woodley, Stephanie; Sole, Gisela

2015-06-01

There is some evidence that hamstring function can be influenced by interventions focusing on the pelvis via an anatomic and neurophysiologic link between these two segments. Previous research demonstrated increased electromyographic activity from injured hamstrings during transition from bipedal to unipedal stance (BUS). The aim of this study was to investigate the effects of a pelvic compression belt (PCB) on electromyographic activity of selected muscles during BUS in sportsmen with and without hamstring injury. Electromyographic amplitudes (normalised to maximum voluntary isometric contraction [MVIC]) of the hamstrings, gluteus maximus, gluteus medius and lumbar multifidus were obtained during BUS from 20 hamstring-injured participants (both sides) and 30 healthy participants (one side, randomly selected). There was an increase in biceps femoris (by 1.23 ± 2.87 %MVIC; p = 0.027) and gluteus maximus (by 0.63 ± 1.13 %MVIC; p = 0.023) electromyographic activity for the hamstring-injured side but no significant differences other than a decrease in multifidus activity (by 1.36 ± 2.92 %MVIC; p = 0.023) were evident for healthy participants while wearing the PCB. However, the effect sizes for these findings were small. Wearing the PCB did not significantly change electromyographic activity of other muscles in either participant group (p > 0.050). Moreover, the magnitude of change induced by the PCB was not significantly different between groups (p > 0.050) for the investigated muscles. Thus, application of a PCB to decrease electromyographic activity of injured hamstrings during BUS is likely to have little effect. Similar research is warranted in participants with acute hamstring injury. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hand Motion Classification Using a Multi-Channel Surface Electromyography Sensor

Directory of Open Access Journals (Sweden)

Dong Sun

2012-01-01

Full Text Available The human hand has multiple degrees of freedom (DOF for achieving high-dexterity motions. Identifying and replicating human hand motions are necessary to perform precise and delicate operations in many applications, such as haptic applications. Surface electromyography (sEMG sensors are a low-cost method for identifying hand motions, in addition to the conventional methods that use data gloves and vision detection. The identification of multiple hand motions is challenging because the error rate typically increases significantly with the addition of more hand motions. Thus, the current study proposes two new methods for feature extraction to solve the problem above. The first method is the extraction of the energy ratio features in the time-domain, which are robust and invariant to motion forces and speeds for the same gesture. The second method is the extraction of the concordance correlation features that describe the relationship between every two channels of the multi-channel sEMG sensor system. The concordance correlation features of a multi-channel sEMG sensor system were shown to provide a vast amount of useful information for identification. Furthermore, a new cascaded-structure classifier is also proposed, in which 11 types of hand gestures can be identified accurately using the newly defined features. Experimental results show that the success rate for the identification of the 11 gestures is significantly high.

Hand motion classification using a multi-channel surface electromyography sensor.

Science.gov (United States)

Tang, Xueyan; Liu, Yunhui; Lv, Congyi; Sun, Dong

2012-01-01

The human hand has multiple degrees of freedom (DOF) for achieving high-dexterity motions. Identifying and replicating human hand motions are necessary to perform precise and delicate operations in many applications, such as haptic applications. Surface electromyography (sEMG) sensors are a low-cost method for identifying hand motions, in addition to the conventional methods that use data gloves and vision detection. The identification of multiple hand motions is challenging because the error rate typically increases significantly with the addition of more hand motions. Thus, the current study proposes two new methods for feature extraction to solve the problem above. The first method is the extraction of the energy ratio features in the time-domain, which are robust and invariant to motion forces and speeds for the same gesture. The second method is the extraction of the concordance correlation features that describe the relationship between every two channels of the multi-channel sEMG sensor system. The concordance correlation features of a multi-channel sEMG sensor system were shown to provide a vast amount of useful information for identification. Furthermore, a new cascaded-structure classifier is also proposed, in which 11 types of hand gestures can be identified accurately using the newly defined features. Experimental results show that the success rate for the identification of the 11 gestures is significantly high.

Quantifying the lumbar flexion-relaxation phenomenon: theory, normative data, and clinical applications.

Science.gov (United States)

Neblett, Randy; Mayer, Tom G; Gatchel, Robert J; Keeley, Janice; Proctor, Tim; Anagnostis, Christopher

2003-07-01

A two-part investigation was conducted: 1) a prospective study of asymptomatic subjects quantitatively comparing trunk mobility to surface electromyographic (sEMG) signals from the erector spinae during trunk flexion; and 2) a prospective repeated-measures cohort study of patients with chronic disabled work-related spinal disorder tested for the flexion-relaxation (FR) phenomenon while measured simultaneously for lumbar spine inclinometric range of motion (ROM). To describe a theoretical model for the potential use of FR unloaded in assessing patients with chronic low back pain patients before and after rehabilitation, and to establish a normative database (Part 1) for subsequent use in comparison to patients with chronic low back pain (Part 2). The second part of the study assessed the clinical utility of combined sEMG and ROM measurements for assessing the FR phenomenon as a test to assist potentially in planning rehabilitation programs, guiding patients' individual rehabilitation progress, and identifying early posttreatment outcome failures. The FR phenomenon has been recognized since 1951, and it can be reproducibly assessed in normal subjects with FR unloaded. It can be found intermittently in patients with chronic low back pain. Recent studies have moved toward deriving formulas to identify FR, but only a few have examined a potential relation between inclinometric lumbar motion measures and the sEMG signal. No previous studies have developed normative data potentially useful for objectively assessing nonoperative treatment progress, effort, or the validity of permanent impairment rating measures. In Part 1, 12 asymptomatic subjects were evaluated in an intra- and interrater repeated-measures protocol to examine reliability of sEMG signal readings in FR, as well as ROM measures at FR and maximum voluntary flexion. The mean sEMG signal averaging right-left electrode recordings, as well as the gross, true, and sacral lumbar ROM measurements, were recorded as

Age-Associated Changes in the Spectral and Statistical Parameters of Surface Electromyogram of Tibialis Anterior

Directory of Open Access Journals (Sweden)

Ariba Siddiqi

2016-01-01

Full Text Available Age-related neuromuscular change of Tibialis Anterior (TA is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD as suitable features to identify age-associated changes in the surface electromyogram (sEMG. Eighteen younger (20–30 years and 18 older (60–85 years cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG’s maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes.

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

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

Clinical experience with a novel electromyographic approach to preventing phrenic nerve injury during cryoballoon ablation in atrial fibrillation.

Science.gov (United States)

Mondésert, Blandine; Andrade, Jason G; Khairy, Paul; Guerra, Peter G; Dyrda, Katia; Macle, Laurent; Rivard, Léna; Thibault, Bernard; Talajic, Mario; Roy, Denis; Dubuc, Marc; Shohoudi, Azadeh

2014-08-01

Phrenic nerve palsy remains the most frequent complication associated with cryoballoon-based pulmonary vein (PV) isolation. We sought to characterize our experience using a novel monitoring technique for the prevention of phrenic nerve palsy. Two hundred consecutive cryoballoon-based PV isolation procedures between October 2010 and October 2013 were studied. In addition to standard abdominal palpation during right phrenic nerve pacing from the superior vena cava, all patients underwent diaphragmatic electromyographic monitoring using surface electrodes. Cryoablation was terminated on any perceived reduction in diaphragmatic motion or a 30% decrease in the compound motor action potential (CMAP). During right-sided ablation, a ≥30% reduction in CMAP amplitude occurred in 49 patients (24.5%). Diaphragmatic motion decreased in 30 of 49 patients and was preceded by a 30% reduction in CMAP amplitude in all. In 82% of cases, this reduction in CMAP amplitude occurred during right superior PV isolation. The baseline CMAP amplitude was 946.5±609.2 mV and decreased by 13.8±13.8% at the end of application. This decrease was more marked in the 33 PVs with a reduction in diaphragmatic motion than in those without (40.9±15.3% versus 11.3±10.5%; Pphrenic nerve palsy persisted beyond the end of the procedure, with all cases recovering within 6 months. Despite the shortened application all veins were isolated. At repeat procedure the right-sided PVs reconnected less frequently than the left-sided PVs in those with phrenic nerve palsy. Electromyographic phrenic nerve monitoring using the surface CMAP is reliable, easy to perform, and offers an early warning to impending phrenic nerve injury. © 2014 American Heart Association, Inc.

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

Reproducibility of 3D kinematics and surface electromyography measurements of mastication.

Science.gov (United States)

Remijn, Lianne; Groen, Brenda E; Speyer, Renée; van Limbeek, Jacques; Nijhuis-van der Sanden, Maria W G

2016-03-01

The aim of this study was to determine the measurement reproducibility for a procedure evaluating the mastication process and to estimate the smallest detectable differences of 3D kinematic and surface electromyography (sEMG) variables. Kinematics of mandible movements and sEMG activity of the masticatory muscles were obtained over two sessions with four conditions: two food textures (biscuit and bread) of two sizes (small and large). Twelve healthy adults (mean age 29.1 years) completed the study. The second to the fifth chewing cycle of 5 bites were used for analyses. The reproducibility per outcome variable was calculated with an intraclass correlation coefficient (ICC) and a Bland-Altman analysis was applied to determine the standard error of measurement relative error of measurement and smallest detectable differences of all variables. ICCs ranged from 0.71 to 0.98 for all outcome variables. The outcome variables consisted of four bite and fourteen chewing cycle variables. The relative standard error of measurement of the bite variables was up to 17.3% for 'time-to-swallow', 'time-to-transport' and 'number of chewing cycles', but ranged from 31.5% to 57.0% for 'change of chewing side'. The relative standard error of measurement ranged from 4.1% to 24.7% for chewing cycle variables and was smaller for kinematic variables than sEMG variables. In general, measurements obtained with 3D kinematics and sEMG are reproducible techniques to assess the mastication process. The duration of the chewing cycle and frequency of chewing were the best reproducible measurements. Change of chewing side could not be reproduced. The published measurement error and smallest detectable differences will aid the interpretation of the results of future clinical studies using the same study variables. Copyright © 2015 Elsevier Inc. All rights reserved.

Time-varying surface electromyography topography as a prognostic tool for chronic low back pain rehabilitation.

Science.gov (United States)

Hu, Yong; Kwok, Jerry Weilun; Tse, Jessica Yuk-Hang; Luk, Keith Dip-Kei

2014-06-01

Nonsurgical rehabilitation therapy is a commonly used strategy to treat chronic low back pain (LBP). The selection of the most appropriate therapeutic options is still a big challenge in clinical practices. Surface electromyography (sEMG) topography has been proposed to be an objective assessment of LBP rehabilitation. The quantitative analysis of dynamic sEMG would provide an objective tool of prognosis for LBP rehabilitation. To evaluate the prognostic value of quantitative sEMG topographic analysis and to verify the accuracy of the performance of proposed time-varying topographic parameters for identifying the patients who have better response toward the rehabilitation program. A retrospective study of consecutive patients. Thirty-eight patients with chronic nonspecific LBP and 43 healthy subjects. The accuracy of the time-varying quantitative sEMG topographic analysis for monitoring LBP rehabilitation progress was determined by calculating the corresponding receiver-operating characteristic (ROC) curves. Physiologic measure was the sEMG during lumbar flexion and extension. Patients who suffered from chronic nonspecific LBP without the history of back surgery and any medical conditions causing acute exacerbation of LBP during the clinical test were enlisted to perform the clinical test during the 12-week physiotherapy (PT) treatment. Low back pain patients were classified into two groups: "responding" and "nonresponding" based on the clinical assessment. The responding group referred to the LBP patients who began to recover after the PT treatment, whereas the nonresponding group referred to some LBP patients who did not recover or got worse after the treatment. The results of the time-varying analysis in the responding group were compared with those in the nonresponding group. In addition, the accuracy of the analysis was analyzed through ROC curves. The time-varying analysis showed discrepancies in the root-mean-square difference (RMSD) parameters between the

Detection of surface electromyography recording time interval without muscle fatigue effect for biceps brachii muscle during maximum voluntary contraction.

Science.gov (United States)

Soylu, Abdullah Ruhi; Arpinar-Avsar, Pinar

2010-08-01

The effects of fatigue on maximum voluntary contraction (MVC) parameters were examined by using force and surface electromyography (sEMG) signals of the biceps brachii muscles (BBM) of 12 subjects. The purpose of the study was to find the sEMG time interval of the MVC recordings which is not affected by the muscle fatigue. At least 10s of force and sEMG signals of BBM were recorded simultaneously during MVC. The subjects reached the maximum force level within 2s by slightly increasing the force, and then contracted the BBM maximally. The time index of each sEMG and force signal were labeled with respect to the time index of the maximum force (i.e. after the time normalization, each sEMG or force signal's 0s time index corresponds to maximum force point). Then, the first 8s of sEMG and force signals were divided into 0.5s intervals. Mean force, median frequency (MF) and integrated EMG (iEMG) values were calculated for each interval. Amplitude normalization was performed by dividing the force signals to their mean values of 0s time intervals (i.e. -0.25 to 0.25s). A similar amplitude normalization procedure was repeated for the iEMG and MF signals. Statistical analysis (Friedman test with Dunn's post hoc test) was performed on the time and amplitude normalized signals (MF, iEMG). Although the ANOVA results did not give statistically significant information about the onset of the muscle fatigue, linear regression (mean force vs. time) showed a decreasing slope (Pearson-r=0.9462, pfatigue starts after the 0s time interval as the muscles cannot attain their peak force levels. This implies that the most reliable interval for MVC calculation which is not affected by the muscle fatigue is from the onset of the EMG activity to the peak force time. Mean, SD, and range of this interval (excluding 2s gradual increase time) for 12 subjects were 2353, 1258ms and 536-4186ms, respectively. Exceeding this interval introduces estimation errors in the maximum amplitude calculations

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…

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

Science.gov (United States)

Zhai, Xiaolong; Jelfs, Beth; Chan, Rosa H M; Tin, Chung

2017-01-01

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.

Fractal feature of sEMG from Flexor digitorum superficialis muscle correlated with levels of contraction during low-level finger flexions.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K; Naik, Ganesh R

2010-01-01

This research paper reports an experimental study on identification of the changes in fractal properties of surface Electromyogram (sEMG) with the changes in the force levels during low-level finger flexions. In the previous study, the authors have identified a novel fractal feature, Maximum fractal length (MFL) as a measure of strength of low-level contractions and has used this feature to identify various wrist and finger movements. This study has tested the relationship between the MFL and force of contraction. The results suggest that changes in MFL is correlated with the changes in contraction levels (20%, 50% and 80% maximum voluntary contraction (MVC)) during low-level muscle activation such as finger flexions. From the statistical analysis and by visualisation using box-plot, it is observed that MFL (p ≈ 0.001) is a more correlated to force of contraction compared to RMS (p≈0.05), even when the muscle contraction is less than 50% MVC during low-level finger flexions. This work has established that this fractal feature will be useful in providing information about changes in levels of force during low-level finger movements for prosthetic control or human computer interface.

The management of lactose intolerance among primary care physicians and its correlation with management by gastroenterologists: the SEPD-SEMG national survey

Directory of Open Access Journals (Sweden)

Federico Argüelles-Arias

2015-09-01

Full Text Available Introduction and aims: The understanding of lactose intolerance (LI is limited in some professional settings. Sociedad Española de Patología Digestiva (SEPD and Sociedad Española de Medicina General (SEMG have developed a survey in order to: a Analyze primary care physicians (PCPs knowledge and clinical management; and b to compare results with those of a previous survey of Spanish gastroenterologists (GEs. Material and methods: An online questionnaire was sent to SEMG members with 27 items on various issues: Demographics, occupational characteristics, outlook on LI, diagnostic tests, treatment, and follow-up. Results were compared to those from a survey of GEs. Results: A total of 456 PCPs responded, versus 477 GEs. PCPs had an older mean age and longer professional experience. Level of understanding of LI was similar, albeit a higher proportion of PCPs lacked epidemiological awareness (p 0.001, and LI symptoms as overlapping those of irritable bowel syndrome (93.5 vs. 88.2%; p = 0.005, although symptoms perceived as suspicious of LI were similar in both groups. Dietary recommendations were recognized as the primary therapeutic approach. Conclusion: This study reveals the outlook of PCPs on LI, and allows comparison with that of GEs, as a basis for the development of strategies aimed at improving LI understanding, approach and management in our setting.

Silent Speech Recognition as an Alternative Communication Device for Persons with Laryngectomy.

Science.gov (United States)

Meltzner, Geoffrey S; Heaton, James T; Deng, Yunbin; De Luca, Gianluca; Roy, Serge H; Kline, Joshua C

2017-12-01

Each year thousands of individuals require surgical removal of their larynx (voice box) due to trauma or disease, and thereby require an alternative voice source or assistive device to verbally communicate. Although natural voice is lost after laryngectomy, most muscles controlling speech articulation remain intact. Surface electromyographic (sEMG) activity of speech musculature can be recorded from the neck and face, and used for automatic speech recognition to provide speech-to-text or synthesized speech as an alternative means of communication. This is true even when speech is mouthed or spoken in a silent (subvocal) manner, making it an appropriate communication platform after laryngectomy. In this study, 8 individuals at least 6 months after total laryngectomy were recorded using 8 sEMG sensors on their face (4) and neck (4) while reading phrases constructed from a 2,500-word vocabulary. A unique set of phrases were used for training phoneme-based recognition models for each of the 39 commonly used phonemes in English, and the remaining phrases were used for testing word recognition of the models based on phoneme identification from running speech. Word error rates were on average 10.3% for the full 8-sensor set (averaging 9.5% for the top 4 participants), and 13.6% when reducing the sensor set to 4 locations per individual (n=7). This study provides a compelling proof-of-concept for sEMG-based alaryngeal speech recognition, with the strong potential to further improve recognition performance.

Electromyographic analysis of postural overload caused by bulletproof vests on public security professionals

Directory of Open Access Journals (Sweden)

Michele Caroline dos Santos

2017-08-01

Full Text Available Abstract Introduction Military police activity individuals performing operational activity remain 12 hours using mandatory safety equipment. This work aimed to verify the electromyographic response in operational military police officers before and after a cycle of two working days. Methods Forty-four male individuals were evaluated, with an average age of 34.59 ± 8.05. The used protocol consisted in the evaluation of paravertebral muscles and rectus abdominis muscles in a maximum isometric voluntary contraction test (MVC during trunk extension movements, starting from the sitting position. Moreover, the Roland-Morris functional evaluation questionnaire and the Corlett and Manenica diagram for painful areas were used. An electromyograph with 16 pre-set channels was used. Signals were processed in time (EMGME and spectral (EMGMF domains, using the MatLab® program. The Shapiro-Wilk test and Wilcoxon Signed Ranks Test were applied. Statistical analyses were performed through the SPSS v21.0 software and Microsoft Office Excel 2010, considering p < 0.05 as significance level. Results Results showed statistical differences in the post-working day for time analysis, an EMGME decrease in the right rectus abdominis muscle (p = 0.016 and in the age-stratified sample, with individuals over 31 years old (p = 0.016; in the spectral analysis, EMGMF reduction in the right iliocostalis (p = 0.027 and right and left side in the stratified sample, in individuals over 31 years old and with more than 10 years of service. Conclusion The used protocol highlighted a decrease in the amplitude of the electromyographic signal, as well as possible muscle fatigue on the right side where officers usually carry their weapons.

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.

Evaluating the Training Effects of Two Swallowing Rehabilitation Therapies Using Surface Electromyography--Chin Tuck Against Resistance (CTAR) Exercise and the Shaker Exercise.

Science.gov (United States)

Sze, Wei Ping; Yoon, Wai Lam; Escoffier, Nicolas; Rickard Liow, Susan J

2016-04-01

In this study, the efficacy of two dysphagia interventions, the Chin Tuck against Resistance (CTAR) and Shaker exercises, were evaluated based on two principles in exercise science-muscle-specificity and training intensity. Both exercises were developed to strengthen the suprahyoid muscles, whose contractions facilitate the opening of the upper esophageal sphincter, thereby improving bolus transfer. Thirty-nine healthy adults performed two trials of both exercises in counter-balanced order. Surface electromyography (sEMG) recordings were simultaneously collected from suprahyoid muscle group and sternocleidomastoid muscle during the exercises. Converging results using sEMG amplitude analyses suggested that the CTAR was more specific in targeting the suprahyoid muscles than the Shaker exercise. Fatigue analyses on sEMG signals further indicated that the suprahyoid muscle group were equally or significantly fatigued (depending on metric), when participants carried out CTAR compared to the Shaker exercise. Importantly, unlike during Shaker exercise, the sternocleidomastoid muscles were significantly less activated and fatigued during CTAR. Lowering the chin against resistance is therefore sufficiently specific and intense to fatigue the suprahyoid muscles.

Electromyographical manifestations of muscle fatigue during different levels of simulated light manual assembly work

NARCIS (Netherlands)

Bosch, T.; Looze, M.P. de; Kingma, I.; Visser, B.; Dieën, J.H. van

2009-01-01

The purpose of this study was to determine whether objective electromyographical manifestations of muscle fatigue develop in the upper trapezius muscle in two assembly tasks involving contractions of different low-intensity levels (8% and 12% MVC) and whether these indications of fatigue are

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...

Surface EMG characteristics of people with multiple sclerosis during static contractions of the knee extensors.

Science.gov (United States)

Scott, Sasha M; Hughes, Adrienne R; Galloway, Stuart D R; Hunter, Angus M

2011-01-01

This study was designed to determine whether any alterations existed in surface electromyography (sEMG) in people with multiple sclerosis (MS) during isometric contractions of the knee extensors. Fifteen people with MS and 14 matched controls (mean ± SD age and body mass index 53·7 ± 10·5 versus 54·6 ± 9·6 years and 27·7 ± 6·1 versus 26·5 ± 4, respectively) completed 20%, 40%, 60% and 80% of their maximal voluntary contraction (MVC) of the knee extensors. sEMG was recorded from the vastus lateralis where muscle fibre conduction velocity (MFCV) and sEMG amplitude (RMS) were assessed. Body composition was determined using dual-energy X-ray absorptiometry and physical activity with the use of accelerometry. People with MS showed significantly (P<0·05) faster MFCV during MVC (6·6 ± 2·7 versus 4·7 ± 1·4 m s(-1) ) and all submaximal contractions, while RMS was significantly (P<0·05) less (0·11 ± 0·03 versus 0·24 ± 0·06 mV) in comparison with the controls. MVC along with specific thigh lean mass to torque, rate of force development and mean physical activity were significantly (P<0·01) less in PwMS. People with MS have elevated MFCV alongside reduced RMS during isometric contraction. This elevation in MFCV should be accounted for when interpreting sEMG from people with MS. © 2010 University of Stirling. Clinical physiology and Functional Imaging © 2010 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Lumbar lordosis angle and trunk and lower-limb electromyographic activity comparison in hip neutral position and external rotation during back squats.

Science.gov (United States)

Oshikawa, Tomoki; Morimoto, Yasuhiro; Kaneoka, Koji

2018-03-01

[Purpose] To compare the lumbar lordosis angle and electromyographic activities of the trunk and lower-limb muscles in the hip neutral position and external rotation during back squats. [Subjects and Methods] Ten healthy males without severe low back pain or lower-limb injury participated in this study. The lumbar lordosis angle and electromyographic activities were measured using three-dimensional motion-capture systems and surface electrodes during four back squats: parallel back squats in the hip neutral position and external rotation and full back squats in the hip neutral position and external rotation. A paired t-test was used to compare parallel and full back squats measurements in the hip neutral position and external rotation, respectively. [Results] During parallel back squats, the average lumbar lordosis angle was significantly larger in hip external rotation than in the hip neutral position. During full back squats, lumbar erector spinae and multifidus activities were significantly lower in hip external rotation than in the hip neutral position, whereas gluteus maximus activity was significantly higher in hip external rotation than in the hip neutral position. [Conclusion] The back squat in hip external rotation induced improvement of lumbar kyphosis, an increasing of the gluteus maximus activity and a decrease of both lumbar erector spinae and multifidus activities.

Electromyographic activity of the erector spinae: The short-effect of one workday for welders with nonspecific chronic low back pain, an observational study.

Science.gov (United States)

Mendes, André Augusto M T; de Freitas, Sandra Maria Sbeghen Ferreira; Amorin, César Ferreira; Cabral, Cristina Maria Nunes; Padula, Rosimeire Simprini

2018-02-06

This study aimed to evaluate the effect of one workday on pain and perceived exertion, muscular strength, and electromyographic activity of the erector spinae muscles in welders with and without low back pain. This is an observational cohort study. Twenty-two welders, metallurgical shipbuilding, were equally divided into 2 groups: low back pain and no low back pain. Pain and perceived exertion. Muscular strength by maximal voluntary contractions and electromyographic activity of right and left erector spinae muscles during maximal voluntary contractions and in the 3 welding positions for 2 periods of the workday (in the morning and at the end of the workday). At the end of workday, the pain increased significantly for the low back pain group (t(22) = 2.448; P= 0.023). The perceived exertion also increased significantly for both groups at the end of workday groups (F(1,22) = 8.570, P= 0.000) and periods (F(1,22) = 8.142, P= 0.000). There were no significant differences between groups and workday periods for muscular strength and electromyographic activity during maximal voluntary contractions of the erector spinae. There was no significance difference for electromyographic activity between groups and workday period and in the 3 welding positions. Although the pain and perceived exertion increased at the end of the workday, these results did not interfere in muscular strength and electromyographic activity of right and left erector spinae muscles. Thus, we can conclude that welders with chronic low back pain had a good physical capacity (muscular strength) and that muscle performance was maintained.

Computation and Evaluation of Features of Surface Electromyogram to Identify the Force of Muscle Contraction and Muscle Fatigue

Directory of Open Access Journals (Sweden)

Sridhar P. Arjunan

2014-01-01

Full Text Available The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC. Six features were considered in this study: normalised spectral index (NSM5, median frequency, root mean square, waveform length, normalised root mean square (NRMS, and increase in synchronization (IIS index. Analysis of variance (ANOVA and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P0.05.

Computation and evaluation of features of surface electromyogram to identify the force of muscle contraction and muscle fatigue.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K; Naik, Ganesh

2014-01-01

The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG) was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC). Six features were considered in this study: normalised spectral index (NSM5), median frequency, root mean square, waveform length, normalised root mean square (NRMS), and increase in synchronization (IIS) index. Analysis of variance (ANOVA) and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P 0.05).

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.

Differential Effectiveness of Electromyograph Feedback, Verbal Relaxation Instructions, and Medication Placebo with Tension Headaches

Science.gov (United States)

Cox, Daniel J.; And Others

1975-01-01

Adults with chronic tension headaches were assigned to auditory electromyograph (EMG) feedback (N=9), to progressive relaxation (N=9), and to placebo treatment (N=9). Data indicated that biofeedback and verbal relaxation instructions were equally superior to the medicine placebo on all measured variables in the direction of clinical improvement,…

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...

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

Effects of the innervation zone on the time and frequency domain parameters of the surface electromyographic signal.

Science.gov (United States)

Smith, Cory M; Housh, Terry J; Herda, Trent J; Zuniga, Jorge M; Ryan, Eric D; Camic, Clayton L; Bergstrom, Haley C; Smith, Doug B; Weir, Joseph P; Cramer, Joel T; Hill, Ethan C; Cochrane, Kristen C; Jenkins, Nathaniel D M; Schmidt, Richard J; Johnson, Glen O

2015-08-01

The purposes of the present study were to examine the effects of electrode placements over, proximal, and distal to the innervation zone (IZ) on electromyographic (EMG) amplitude (RMS) and frequency (MPF) responses during: (1) a maximal voluntary isometric contraction (MVIC), and; (2) a sustained, submaximal isometric muscle action. A linear array was used to record EMG signals from the vastus lateralis over the IZ, 30mm proximal, and 30mm distal to the IZ during an MVIC and a sustained isometric muscle action of the leg extensors at 50% MVIC. During the MVIC, lower EMG RMS (p>0.05) and greater EMG MPF (ptime relationships over, proximal, and distal to the IZ occurred. Thus, the results of the present study indicated that during an MVIC, EMG RMS and MPF values recorded over the IZ are not comparable to those away from the IZ. However, the rates of fatigue-induced changes in EMG RMS and MPF during sustained, submaximal isometric muscle actions of the leg extensors were the same regardless of the electrode placement locations relative to the IZ. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electromyographic analysis of the three subdivisions of gluteus medius during weight-bearing exercises

Directory of Open Access Journals (Sweden)

O'Sullivan Kieran

2010-07-01

Full Text Available Abstract Background Gluteus medius (GM dysfunction is associated with many musculoskeletal disorders. Rehabilitation exercises aimed at strengthening GM appear to improve lower limb kinematics and reduce pain. However, there is a lack of evidence to identify which exercises best activate GM. In particular, as GM consists of three distinct subdivisions, it is unclear if GM activation is consistent across these subdivisions during exercise. The aim of this study was to determine the activation of the anterior, middle and posterior subdivisions of GM during weight-bearing exercises. Methods A single session, repeated-measures design. The activity of each GM subdivision was measured in 15 pain-free subjects using surface electromyography (sEMG during three weight-bearing exercises; wall squat (WS, pelvic drop (PD and wall press (WP. Muscle activity was expressed relative to maximum voluntary isometric contraction (MVIC. Differences in muscle activation were determined using one-way repeated measures ANOVA with post-hoc Bonferroni analysis. Results The activation of each GM subdivision during the exercises was significantly different (interaction effect; p Discussion Posterior GM displayed higher activation across all three exercises than both anterior and middle GM. The WP produced the highest %MVIC activation for all GM subdivisions, and this was most pronounced for posterior GM. Clinicians may use these results to effectively progress strengthening exercises for GM in the rehabilitation of lower extremity injuries.

Transient electromyographic findings in serotonergic toxicity due to combination of essitalopram and isoniazid

Directory of Open Access Journals (Sweden)

Çagdas Erdogan

2013-01-01

Full Text Available Here, we report a case of serotonergic toxicity due to combination of essitalopram and isoniazid, which was rarely reported before. Moreover, we observed transient neurogenic denervation potentials in needle electromyography, which disappeared with the treatment of serotonergic toxicity. As to our best knowledge, this is the first case, reporting transient electromyographic changes probably due to serotonergic toxicity.

Electromyographic control of functional electrical stimulation in selected patients.

Science.gov (United States)

Graupe, D; Kohn, K H; Basseas, S; Naccarato, E

1984-07-01

The paper describes initial results of above-lesion electromyographic (EMG) controlled functional electrical stimulation (FES) of paraplegics. Such controlled stimulation is to provide upper-motor-neuron paraplegics (T5 to T12) with self-controlled standing and some walking without braces and with only the help of walkers or crutches. The above-lesion EMG signal employed serves to map the posture of the patient's upper trunk via a computerized mapping of the temporal patterns of that EMG. Such control also has an inherent safety feature in that it prevents the patient from performing a lower-limb movement via FES unless his trunk posture is adequate. Copyright 2013, SLACK Incorporated.

Influence of sustained submaximal clenching fatigue test on electromyographic activity and maximum voluntary bite forces in healthy subjects and patients with temporomandibular disorders.

Science.gov (United States)

Xu, L; Fan, S; Cai, B; Fang, Z; Jiang, X

2017-05-01

This study aimed to investigate whether the fatigue induced by sustained motor task in the jaw elevator muscles differed between healthy subjects and patients with temporomandibular disorder (TMD). Fifteen patients with TMD and thirteen age- and sex-matched healthy controls performed a fatigue test consisting of sustained clenching contractions at 30% maximal voluntary clenching intensity until test failure (the criterion for terminating the fatigue test was when the biting force decreased by 10% or more from the target force consecutively for >3 s). The pre- and post-maximal bite forces (MBFs) were measured. Surface electromyographic signals were recorded from the superficial masseter muscles and anterior temporal muscles bilaterally, and the median frequency at the beginning, middle and end of the fatigue test was calculated. The duration of the fatigue test was also quantified. Both pre- and post-MBFs were lower in patients with TMD than in controls (P fatigue test in TMD patients was significantly shorter than that of the controls (P fatigued, but the electromyographic activation process during the fatigue test is similar between healthy subjects and patients with TMD. However, the mechanisms involved in this process remain unclear, and further research is warranted. © 2017 John Wiley & Sons Ltd.

Surface electromyography based muscle fatigue detection using high-resolution time-frequency methods and machine learning algorithms.

Science.gov (United States)

Karthick, P A; Ghosh, Diptasree Maitra; Ramakrishnan, S

2018-02-01

Surface electromyography (sEMG) based muscle fatigue research is widely preferred in sports science and occupational/rehabilitation studies due to its noninvasiveness. However, these signals are complex, multicomponent and highly nonstationary with large inter-subject variations, particularly during dynamic contractions. Hence, time-frequency based machine learning methodologies can improve the design of automated system for these signals. In this work, the analysis based on high-resolution time-frequency methods, namely, Stockwell transform (S-transform), B-distribution (BD) and extended modified B-distribution (EMBD) are proposed to differentiate the dynamic muscle nonfatigue and fatigue conditions. The nonfatigue and fatigue segments of sEMG signals recorded from the biceps brachii of 52 healthy volunteers are preprocessed and subjected to S-transform, BD and EMBD. Twelve features are extracted from each method and prominent features are selected using genetic algorithm (GA) and binary particle swarm optimization (BPSO). Five machine learning algorithms, namely, naïve Bayes, support vector machine (SVM) of polynomial and radial basis kernel, random forest and rotation forests are used for the classification. The results show that all the proposed time-frequency distributions (TFDs) are able to show the nonstationary variations of sEMG signals. Most of the features exhibit statistically significant difference in the muscle fatigue and nonfatigue conditions. The maximum number of features (66%) is reduced by GA and BPSO for EMBD and BD-TFD respectively. The combination of EMBD- polynomial kernel based SVM is found to be most accurate (91% accuracy) in classifying the conditions with the features selected using GA. The proposed methods are found to be capable of handling the nonstationary and multicomponent variations of sEMG signals recorded in dynamic fatiguing contractions. Particularly, the combination of EMBD- polynomial kernel based SVM could be used to

Analysis of progression of fatigue conditions in biceps brachii muscles using surface electromyography signals and complexity based features.

Science.gov (United States)

Karthick, P A; Makaram, Navaneethakrishna; Ramakrishnan, S

2014-01-01

Muscle fatigue is a neuromuscular condition where muscle performance decreases due to sustained or intense contraction. It is experienced by both normal and abnormal subjects. In this work, an attempt has been made to analyze the progression of muscle fatigue in biceps brachii muscles using surface electromyography (sEMG) signals. The sEMG signals are recorded from fifty healthy volunteers during dynamic contractions under well defined protocol. The acquired signals are preprocessed and segmented in to six equal parts for further analysis. The features, such as activity, mobility, complexity, sample entropy and spectral entropy are extracted from all six zones. The results are found showing that the extracted features except complexity feature have significant variations in differentiating non-fatigue and fatigue zone respectively. Thus, it appears that, these features are useful in automated analysis of various neuromuscular activities in normal and pathological conditions.

Discrete wavelet transform analysis of surface electromyography for the fatigue assessment of neck and shoulder muscles.

Science.gov (United States)

Chowdhury, Suman Kanti; Nimbarte, Ashish D; Jaridi, Majid; Creese, Robert C

2013-10-01

Assessment of neuromuscular fatigue is essential for early detection and prevention of risks associated with work-related musculoskeletal disorders. In recent years, discrete wavelet transform (DWT) of surface electromyography (SEMG) has been used to evaluate muscle fatigue, especially during dynamic contractions when the SEMG signal is non-stationary. However, its application to the assessment of work-related neck and shoulder muscle fatigue is not well established. Therefore, the purpose of this study was to establish DWT analysis as a suitable method to conduct quantitative assessment of neck and shoulder muscle fatigue under dynamic repetitive conditions. Ten human participants performed 40min of fatiguing repetitive arm and neck exertions while SEMG data from the upper trapezius and sternocleidomastoid muscles were recorded. The ten of the most commonly used wavelet functions were used to conduct the DWT analysis. Spectral changes estimated using power of wavelet coefficients in the 12-23Hz frequency band showed the highest sensitivity to fatigue induced by the dynamic repetitive exertions. Although most of the wavelet functions tested in this study reasonably demonstrated the expected power trend with fatigue development and recovery, the overall performance of the "Rbio3.1" wavelet in terms of power estimation and statistical significance was better than the remaining nine wavelets. Copyright © 2013 Elsevier Ltd. All rights reserved.

The influence of foot arch on ankle joint torques andon sEMG signal amplitude in selected lower leg muscles

Directory of Open Access Journals (Sweden)

Żebrowska Kinga

2016-09-01

Full Text Available Introduction: This study sought to assess the influence of proper foot arch on electromyographic activity of selected lower limb muscles. The aim of this work was to evaluate the effects of foot arch on the activity of selected muscles and to determine whether electromyography might help to identify types of flat feet resulting from muscle- or ligament-related causes.

A more precise, repeatable and diagnostic alternative to surface electromyography

DEFF Research Database (Denmark)

Harrison, Adrian P

2018-01-01

Acoustic myography (AMG) enables a detailed and accurate measurement of those muscles involved in a particular movement and is independent of electrical signals between the nerve and muscle, measuring solely muscle contractions, unlike surface electromyography (sEMG). With modern amplifiers....../coordination (E-score), spatial summation (S-score) and temporal summation (T-score). It is concluded that modern AMG units have the potential to accurately assess patients with neuromuscular and musculoskeletal complaints in hospital clinics, home monitoring situations as well as sports settings....

Surface electromyography and ultrasound evaluation of pelvic floor muscles in hyperandrogenic women.

Science.gov (United States)

Vassimon, Flávia Ignácio Antonio; Ferreira, Cristine Homsi Jorge; Martins, Wellington Paula; Ferriani, Rui Alberto; Batista, Roberta Leopoldino de Andrade; Bo, Kari

2016-04-01

High levels of androgens increase muscle mass. Due to the characteristics of hyperandrogenism in polycystic ovary syndrome (PCOS), it is plausible that women with PCOS may have increased pelvic floor muscle (PFM) thickness and neuromuscular activity levels compared with controls. The aim of this study was to assess PFM thickness and neuromuscular activity among hyperandrogenic women with PCOS and controls. This was an observational, cross-sectional, case-control study evaluating PFM by ultrasound (US) and surface electromyography (sEMG) in nonobese women with and without PCOS. Seventy-two women were divided into two groups: PCOS (n = 33) and controls (n = 39). PFM thickness during contraction was assessed by US (Vingmed CFM 800). Pelvic floor muscle activity was assessed by sEMG (MyoTrac Infinit) during contractions at different time lengths: quick, and 8 and 60 s. Descriptive analysis, analysis of variance (ANOVA), and Student's t test were used for statistical analyses. There were no significant differences in PFM sEMG activity between PCOS and controls in any of the contractions: quick contraction (73.23 mV/ 71.56 mV; p = 0.62), 8 s (55.77 mV/ 54.17 mV; p = 0.74), and 60 s (49.26 mV/ 47.32 mV; p = 0.68), respectively. There was no difference in PFM thickness during contractions evaluated by US between PCOS and controls (12.78 mm/ 13.43 mm; p =  .48). This study did not find statistically significant differences in pelvic floor muscle thickness or in muscle activity between PCOS women and controls.

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

. 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...

The use of surface electromyography as a tool in differentiating temporomandibular disorders from neck disorders.

Science.gov (United States)

Ferrario, Virgilio F; Tartaglia, Gianluca M; Luraghi, Francesca E; Sforza, Chiarella

2007-11-01

The aim of this study was to assess the electromyographic characteristics of the masticatory muscles (masseter and temporalis) of patients with either "temporomandibular joint disorder" or "neck pain". Surface electromyography of the right and left masseter and temporalis muscles was performed during maximum teeth clenching in 38 patients aged 21-67 years who had either (a) temporomandibular joint disorder (24 patients); (b) "neck pain" (13 patients). Ninety-five control, healthy subjects were also examined. During clenching, standardized total muscle activities (electromyographic potentials over time) were significantly different in the three groups: 75 microV/microVs% in the temporomandibular joint disorder patients, 124 microV/microVs% in the neck pain patients, and 95 microV/microVs% in the control subjects (analysis of variance, Ptemporomandibular joint disorder patients also had significantly (Pneck pain patients (87%) or control subjects (92%). A linear discriminant function analysis allowed a significant separation between the two patient groups, with a single patient error of 18.2%. Surface electromyographic analysis during clenching allowed to differentiate between patients with a temporomandibular joint disorder and patients with a neck pain problem.

Patterns of motor recruitment can be determined using surface EMG.

Science.gov (United States)

Wakeling, James M

2009-04-01

Previous studies have reported how different populations of motor units (MUs) can be recruited during dynamic and locomotor tasks. It was hypothesised that the higher-threshold units would contribute higher-frequency components to the sEMG spectra due to their faster conduction velocities, and thus recruitment patterns that increase the proportion of high-threshold units active would lead to higher-frequency elements in the sEMG spectra. This idea was tested by using a model of varying recruitment coupled to a three-layer volume conductor model to generate a series of sEMG signals. The recruitment varied from (A) orderly recruitment where the lowest-threshold MUs were initially activated and higher-threshold MUs were sequentially recruited as the contraction progressed, (B) a recurrent inhibition model that started with orderly recruitment, but as the higher-threshold units were activated they inhibited the lower-threshold MUs (C) nine models with intermediate properties that were graded between these two extremes. The sEMG was processed using wavelet analysis and the spectral properties quantified by their mean frequency, and an angle theta that was determined from the principal components of the spectra. Recruitment strategies that resulted in a greater proportion of faster MUs being active had a significantly lower theta and higher mean frequency.

Differences in chewing behaviors between healthy fully dentate young and older adults assessed by electromyographic recordings.

Science.gov (United States)

Zhu, Yong; Hollis, James H

2015-01-01

To characterize changes in chewing behaviors associated with healthy aging, 10 young and 10 older fully dentate healthy participants were enrolled in this study. They chewed carrot samples that differed in hardness until their normal swallowing threshold. Their chewing behaviors were assessed using an electromyographic recording device. Adjusting for gender and body mass index, older adults had a higher number of chewing cycles (p = 0.020), a longer chewing duration (p chewing rate (p = 0.002), a greater maximal electromyographic voltage (p = 0.003) and a greater muscle activity (p = 0.002) before they could comfortably swallow the food bolus. A statistically significant main effect of food hardness on the number of chewing cycles, chewing duration, chewing rate and muscle activity was also observed (p < 0.001 for all). These results suggest that reduced mastication efficiency is associated with healthy aging in fully dentate adults. This ingestive behavior may contribute to aging-related reduction in appetite in older adults.

Surface electromyography based muscle fatigue analysis for stroke patients at different Brunnstrom stages.

Science.gov (United States)

Yinjun Tu; Zhe Zhang; Xudong Gu; Qiang Fang

2016-08-01

Muscle fatigue analysis has been an important topic in sport and rehabilitation medicine due to its role in muscle performance evaluation and pathology investigation. This paper proposes a surface electromyography (sEMG) based muscle fatigue analysis approach which was specifically designed for stroke rehabilitation applications. 14 stroke patients from 5 different Brunnstrom recovery stage groups were involved in the experiment and features including median frequency and mean power frequency were extracted from the collected sEMG samples for investigation. After signal decomposition, the decline of motor unit firing rate of patients from different groups had also been studied. Statistically significant presence of fatigue had been observed in deltoideus medius and extensor digitorum communis of patients at early recovery stages (P0.01). It had also been discovered that the motor unit firing frequency declines with a range positively correlated to the recovery stage during repetitive movements. Based on the experiment result, it can be verified that as the recovery stage increases, the central nervous system's control ability strengthens and the patient motion becomes more stable and resistive to fatigue.

Immediate effect of selective neuromuscular electrical stimulation on the electromyographic activity of the vastus medialis oblique muscle

Directory of Open Access Journals (Sweden)

Denise DalAva Augusto

2008-07-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n2p155 The Patellofemoral pain syndrome (PFPS is described as an anterior or retropatellar knee pain in the absence of other associated diseases, and has often been associated with dysfunction of the vastus medialis oblique muscle (VMO. However, several studies have demonstrated the impossibility of selectively activating this muscle with exercises. The aim of the present study was to analyze the immediate effect of neuromuscular electrical stimulation of VMO muscle by means of monitoring the electromyographic activity of the vastus medialis oblique (VMO and vastus lateralis (VL muscles. Eighteen healthy women with a mean age of 23.2 years and mean BMI of 20 Kg/m2 were evaluated. The study protocol included electromyographic analysis of VMO and VL muscles, before and immediately after neuromuscular electrical stimulation of the VMO muscle. During the electromyographic analysis, the volunteers performed maximal voluntary isometric contraction in a 60° knee extension on an isokinetic dynamometer. “Russian current” apparatus was used for electrical stimulation. Results: The data analysis demonstrated a signifi cant increase in VMO activation intensity immediately after it had been electrically stimulated (p=0.0125, whereas VL activation intensity exhibited no signifi cant increase (p=0.924. Moreover, a significant increase in the VMO/VL ratio was also detected (p=0.048. In this study it was observed that electrical stimulation modifiedthe VMO/VL ratio, which suggests electrical stimulation has a benefi cial effect on VMO muscle strength.

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.

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.

Effects of 12-wk eccentric calf muscle training on muscle-tendon glucose uptake and SEMG in patients with chronic Achilles tendon pain

DEFF Research Database (Denmark)

Masood, Tahir; Kalliokoski, Kari; Magnusson, S Peter

2014-01-01

High-load eccentric exercises have been a key component in the conservative management of chronic Achilles tendinopathy. This study investigated the effects of a 12-wk progressive, home-based eccentric rehabilitation program on ankle plantar flexors' glucose uptake (GU) and myoelectric activity......, while the asymptomatic leg displayed higher uptake for medial gastrocnemius and flexor hallucis longus (P tendon GU than the controls (P effect on the tendon GU. Concerning SEMG, at baseline, soleus showed more relative...... within- or between-group differences. Eccentric rehabilitation was effective in decreasing subjective severity of Achilles tendinopathy. It also resulted in redistribution of relative electrical activity, but not metabolic activity, within the triceps surae muscle....

Influence of the "Slingshot" bench press training aid on bench press kinematics and neuromuscular activity in competitive powerlifters.

Science.gov (United States)

Dugdale, James H; Hunter, Angus; Di Virgilio, Thomas; Macgregor, Lewis J; Hamilton, D Lee

2017-02-13

This study examined the acute effects of the 'Slingshot' on bench-press performance, prime-mover surface electromyographic (sEMG) amplitude, and barbell velocity during maximal and submaximal bench-pressing in competitive male powerlifters. Fifteen male powerlifters (mean ± SD age: 27.05 ± 5.94 years; mass: 94.15kg; 1RM bench-press: 139.7 ± 16.79kg) participated in the study. Bench-press strength, average barbell velocity, and sEMG amplitude of the prime mover muscles (triceps brachii, pectoralis major and anterior deltoid) were measured during two conditions; 'Raw' (without use of any assistance) and 'Slingshot' [using the 'Slingshot' to perform both the weight achieved during 'Raw' 1RM testing (Raw max/SS), and absolute 1RM using the 'Slingshot' (SS)]. The results showed that the 'Slingshot' significantly increased bench press 1RM performance by a mean ± SD of 20.67kg ± 3.4kg. Barbell velocity and stick point analysis indicate that this improvement is likely driven by an increase in peak and pre-stick barbell velocity as triceps RMS was lower throughout all rep max phases with the 'Slingshot'. The 'Slingshot' also caused reductions in RMS, specifically of the triceps at all rep ranges but barbell velocity was better maintained in the last reps of all sets. These data indicate that the 'Slingshot' specifically de-loaded the triceps muscle throughout all rep ranges and provide assistance to maintaining barbell velocity under fatigue during later repetitions of multiple-repetition sets. The 'Slingshot' training aid could therefore be used in de-load phases of bench press training or as an over-reaching and velocity training aid.

Electromyographic analysis of knee push up plus variations: what is the influence of the kinetic chain on scapular muscle activity?

Science.gov (United States)

Maenhout, A; Van Praet, K; Pizzi, L; Van Herzeele, M; Cools, A

2010-11-01

First, to look for appropriate closed kinetic chain exercises to restore intramuscular imbalance between upper trapezius (UT) and serratus anterior (SA) in overhead athletes. Second, to determine the influence of using diagonal pattern muscle recruitment during knee push up plus (KPP) exercises on scapular electromyographic activity. Single group repeated-measures design. Controlled laboratory study. Thirty-two physically active individuals in good general health who did not have a history of neck and/or shoulder injury or surgery nor participated in high-level overhead sports or performed upper limb strength training for more than 5 h/week. Interventions Subjects performed the standard KPP and six variations. Electromyographic activity of the three trapezius parts and the SA. Four exercises with a low UT/SA can be selected for rehabilitation of intramuscular balance: standard KPP, KPP with homolateral leg extension, KPP with a wobble board and homolateral leg extension and one-handed KPP. The use of a wobble board during KPP exercises and performance on one hand has no influence on SA electromyographic activity. Heterolateral leg extension during KPP stimulates lower trapezius activity, whereas homolateral leg extension stimulates SA activity. In case of intramuscular scapular imbalance, some exercises are preferable over others because of their low UT/SA ratio. The use of a kinetic chain approach during KPP exercises influences scapular muscle activity.

Electromyographic Responses to Emotional Facial Expressions in 6-7 Year Olds with Autism Spectrum Disorders

Science.gov (United States)

Deschamps, P. K. H.; Coppes, L.; Kenemans, J. L.; Schutter, D. J. L. G.; Matthys, W.

2015-01-01

This study aimed to examine facial mimicry in 6-7 year old children with autism spectrum disorder (ASD) and to explore whether facial mimicry was related to the severity of impairment in social responsiveness. Facial electromyographic activity in response to angry, fearful, sad and happy facial expressions was recorded in twenty 6-7 year old…

Electromyographic analysis of an eccentric calf muscle exercise in persons with and without Achilles tendinopathy.

Science.gov (United States)

Reid, Duncan; McNair, Peter J; Johnson, Shelley; Potts, Geoff; Witvrouw, Erik; Mahieu, Nele

2012-08-01

To compare surface electromyographic (EMG) activity of the gastrocnemius and soleus muscles between persons with and without Achilles tendinopathy (AT) during an eccentric muscle exercise in different knee joint positions. Repeated measures design. Research laboratory. Participants (n = 18) diagnosed with AT and 18 control subjects were recruited. Gastrocnemius and soleus muscle activity was examined by surface (EMG) during extended and flexed knee joint conditions while performing the eccentric training technique. The EMG data were expressed as a percentage of a maximum voluntary contraction (MVC). EMG activity was notably higher (mean difference: 10%, effect size: 0.59) in those subjects with AT. Irrespective of the presence of AT, there was a significant interaction effect between muscle and joint position. The gastrocnemius muscle was significantly more active in the extended knee condition and soleus muscle activity was unchanged across joint positions. The results indicated that the presence of AT influenced calf muscle activity levels during performance of the eccentric exercise. There were differences in muscle activity during the extended and flexed knee conditions. This result does support performing Alfredson, Pietila, Jonsson, and Lorentzon (1998) eccentric exercise in an extended knee position but the specific effects of the knee flexed position on the Achilles tendon during eccentric exercise have yet to be determined, particularly in those with AT. Copyright © 2011 Elsevier Ltd. All rights reserved.

SURFACE ELECTROMYOGRAPHY IN BIOMECHANICS: APPLICATIONS AND SIGNAL ANALYSIS ASPECTS

Directory of Open Access Journals (Sweden)

DEAK GRAłIELA-FLAVIA

2009-12-01

Full Text Available Surface electromyography (SEMG is a technique for detecting and recording the electrical activity of the muscles using surface electrodes. The EMG signal is used in biomechanics mainly as an indicator of the initiation of muscle activation, as an indicator of the force produced by a contracting muscle, and as an index ofthe fatigue occurring within a muscle. EMG, used as a method of investigation, can tell us if the muscle is active or not, if the muscle is more or less active, when it is on or off, how much active is it, and finally, if it fatigues.The purpose of this article is to discuss some specific EMG signal analysis aspects with emphasis on comparison type analysis and frequency fatigue analysis.

[Recognition of walking stance phase and swing phase based on moving window].

Science.gov (United States)

Geng, Xiaobo; Yang, Peng; Wang, Xinran; Geng, Yanli; Han, Yu

2014-04-01

Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.

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.

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.

Comparison of regression models for estimation of isometric wrist joint torques using surface electromyography

Directory of Open Access Journals (Sweden)

Menon Carlo

2011-09-01

Full Text Available Abstract Background Several regression models have been proposed for estimation of isometric joint torque using surface electromyography (SEMG signals. Common issues related to torque estimation models are degradation of model accuracy with passage of time, electrode displacement, and alteration of limb posture. This work compares the performance of the most commonly used regression models under these circumstances, in order to assist researchers with identifying the most appropriate model for a specific biomedical application. Methods Eleven healthy volunteers participated in this study. A custom-built rig, equipped with a torque sensor, was used to measure isometric torque as each volunteer flexed and extended his wrist. SEMG signals from eight forearm muscles, in addition to wrist joint torque data were gathered during the experiment. Additional data were gathered one hour and twenty-four hours following the completion of the first data gathering session, for the purpose of evaluating the effects of passage of time and electrode displacement on accuracy of models. Acquired SEMG signals were filtered, rectified, normalized and then fed to models for training. Results It was shown that mean adjusted coefficient of determination (Ra2 values decrease between 20%-35% for different models after one hour while altering arm posture decreased mean Ra2 values between 64% to 74% for different models. Conclusions Model estimation accuracy drops significantly with passage of time, electrode displacement, and alteration of limb posture. Therefore model retraining is crucial for preserving estimation accuracy. Data resampling can significantly reduce model training time without losing estimation accuracy. Among the models compared, ordinary least squares linear regression model (OLS was shown to have high isometric torque estimation accuracy combined with very short training times.

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.

Analysis of Muscle Fatigue Progression using Cyclostationary Property of Surface Electromyography Signals.

Science.gov (United States)

Karthick, P A; Venugopal, G; Ramakrishnan, S

2016-01-01

Analysis of neuromuscular fatigue finds various applications ranging from clinical studies to biomechanics. Surface electromyography (sEMG) signals are widely used for these studies due to its non-invasiveness. During cyclic dynamic contractions, these signals are nonstationary and cyclostationary. In recent years, several nonstationary methods have been employed for the muscle fatigue analysis. However, cyclostationary based approach is not well established for the assessment of muscle fatigue. In this work, cyclostationarity associated with the biceps brachii muscle fatigue progression is analyzed using sEMG signals and Spectral Correlation Density (SCD) functions. Signals are recorded from fifty healthy adult volunteers during dynamic contractions under a prescribed protocol. These signals are preprocessed and are divided into three segments, namely, non-fatigue, first muscle discomfort and fatigue zones. Then SCD is estimated using fast Fourier transform accumulation method. Further, Cyclic Frequency Spectral Density (CFSD) is calculated from the SCD spectrum. Two features, namely, cyclic frequency spectral area (CFSA) and cyclic frequency spectral entropy (CFSE) are proposed to study the progression of muscle fatigue. Additionally, degree of cyclostationarity (DCS) is computed to quantify the amount of cyclostationarity present in the signals. Results show that there is a progressive increase in cyclostationary during the progression of muscle fatigue. CFSA shows an increasing trend in muscle fatiguing contraction. However, CFSE shows a decreasing trend. It is observed that when the muscle progresses from non-fatigue to fatigue condition, the mean DCS of fifty subjects increases from 0.016 to 0.99. All the extracted features found to be distinct and statistically significant in the three zones of muscle contraction (p < 0.05). It appears that these SCD features could be useful in the automated analysis of sEMG signals for different neuromuscular conditions.

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.

Effects of a sour bolus on the intramuscular electromyographic (EMG) activity of muscles in the submental region.

Science.gov (United States)

Palmer, Phyllis M; McCulloch, Timothy M; Jaffe, Debra; Neel, Amy T

2005-01-01

A sour bolus has been used as a modality in the treatment of oropharyngeal dysphagia based on the hypothesis that this stimulus provides an effective preswallow sensory input that lowers the threshold required to trigger a pharyngeal swallow. The result is a more immediate swallow onset time. Additionally, the sour bolus may invigorate the oral muscles resulting in stronger contractions during the swallow. The purpose of this investigation was to compare the intramuscular electromyographic activity of the mylohyoid, geniohyoid, and anterior belly of the digastric muscles during sour and water boluses with regard to duration, strength, and timing of muscle activation. Muscle duration, swallow onset time, and pattern of muscle activation did not differ for the two bolus types. Muscle activation time was more tightly approximated across the onsets of the three muscles when a sour bolus was used. A sour bolus also resulted in a stronger muscle contraction as evidenced by greater electromyographic activity. These data support the use of a sour bolus as part of a treatment paradigm.

Effects of Novel Guidance Tubing Gait on Electromyographic Neuromuscular Imbalance and Joint Angular Kinematics During Locomotion in Hemiparetic Stroke Patients.

Science.gov (United States)

Lee, Jeong J; You, Joshua Sung H

2017-12-01

To compare the immediate effects of conventional treadmill gait and guidance tubing gait (GTG) on electromyographic neuromuscular imbalance and knee joint kinematics in hemiparetic gait. Case-control study. University medical center. Participants (N=33; 19 men, 14 women) were patients with hemiparetic stroke (n=18 [experimental]; mean age ± SD, 39.2±16.8y) and healthy controls (n=15; mean age ± SD, 26.3±2.6y). The GTG was provided for approximately 30 minutes and involved application of an assistive guidance force using the tubing, specifically to improve knee joint stabilization during midstance and increase knee joint flexion during midswing phase. Clinical tests included the Korean Mini-Mental State Examination, Modified Ashworth Scale, Berg Balance Scale, manual muscle test, and knee joint range of motion and sensory tests. Knee joint muscle electromyographic and kinematic analyses were determined at pretest and posttest. After the intervention, the experimental group showed significantly greater improvements in balanced quadriceps and hamstring electromyographic coactivation and knee joint kinematics relative to the control group (P=.005). The GTG intervention decreased overactive hamstring activity (P=.018) and reciprocally increased quadriceps activity (Pjoint kinematic analysis showed significant changes in the hemiparetic stroke group (P=.004). This study demonstrates the effectiveness of the tubing gait condition to restore knee joint muscle imbalance and kinematics in individuals with hemiparetic stroke who present with an abnormal hyperextension knee gait. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

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.

Mechanomyography versus Electromyography, in monitoring the muscular fatigue

Directory of Open Access Journals (Sweden)

Tarata Mihai T

2003-02-01

Full Text Available Abstract Background The use of the mechanomyogram (MMG which detects muscular vibrations generated by fused individual fiber twitches has been refined. The study addresses a comparison of the MMG and surface electromyogram (SEMG in monitoring muscle fatigue. Methods The SEMG and MMG were recorded simultaneously from the same territory of motor units in two muscles (Biceps, Brachioradialis of the human (n = 18, during sustained contraction at 25 % MVC (maximal voluntary contraction. Results The RMS (root mean square of the SEMG and MMG increased with advancing fatigue; MF (median frequency of the PSD (power density spectra progressively decreased from the onset of the contraction. These findings (both muscles, all subjects, demonstrate both through the SEMG and MMG a central component of the fatigue. The MF regression slopes of MMG were closer to each other between men and women (Biceps 1.55%; Brachialis 13.2% than were the SEMG MF slopes (Biceps 25.32%; Brachialis 17.72%, which shows a smaller inter-sex variability for the MMG vs. SEMG. Conclusion The study presents another quantitative comparison (MF, RMS of MMG and SEMG, showing that MMG signal can be used for indication of the degree of muscle activation and for monitoring the muscle fatigue when the application of SEMG is not feasible (chronical implants, adverse environments contaminated by electrical noise.

Normalised Mutual Information of High-Density Surface Electromyography during Muscle Fatigue

Directory of Open Access Journals (Sweden)

Adrian Bingham

2017-12-01

Full Text Available This study has developed a technique for identifying the presence of muscle fatigue based on the spatial changes of the normalised mutual information (NMI between multiple high density surface electromyography (HD-sEMG channels. Muscle fatigue in the tibialis anterior (TA during isometric contractions at 40% and 80% maximum voluntary contraction levels was investigated in ten healthy participants (Age range: 21 to 35 years; Mean age = 26 years; Male = 4, Female = 6. HD-sEMG was used to record 64 channels of sEMG using a 16 by 4 electrode array placed over the TA. The NMI of each electrode with every other electrode was calculated to form an NMI distribution for each electrode. The total NMI for each electrode (the summation of the electrode’s NMI distribution highlighted regions of high dependence in the electrode array and was observed to increase as the muscle fatigued. To summarise this increase, a function, M(k, was defined and was found to be significantly affected by fatigue and not by contraction force. The technique discussed in this study has overcome issues regarding electrode placement and was used to investigate how the dependences between sEMG signals within the same muscle change spatially during fatigue.

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

Science.gov (United States)

Xie, Hong-Bo; Guo, Tianruo; Bai, Siwei; Dokos, Socrates

2014-02-03

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.

Application of advanced biomechanical methods in studying low back pain – recent development in estimation of lower back loads and large-array surface electromyography and findings

Directory of Open Access Journals (Sweden)

Bazrgari B

2017-07-01

Full Text Available Babak Bazrgari,1 Ting Xia2 1F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY, 2Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA Abstract: Low back pain (LBP is a major public health problem and the leading disabling musculoskeletal disorder globally. A number of biomechanical methods using kinematic, kinetic and/or neuromuscular approaches have been used to study LBP. In this narrative review, we report recent developments in two biomechanical methods: estimation of lower back loads and large-array surface electromyography (LA-SEMG and the findings associated with LBP. The ability to estimate lower back loads is very important for the prevention and the management of work-related low back injuries based on the mechanical loading model as one category of LBP classification. The methods used for estimation of lower back loads vary from simple rigid link-segment models to sophisticated, optimization-based finite element models. In general, reviewed reports of differences in mechanical loads experienced in lower back tissues between patients with LBP and asymptomatic individuals are not consistent. Such lack of consistency is primarily due to differences in activities under which lower back mechanical loads were investigated as well as heterogeneity of patient populations. The ability to examine trunk neuromuscular behavior is particularly relevant to the motor control model, another category of LBP classification. LA-SEMG not only is noninvasive but also provides spatial resolution within and across muscle groups. Studies using LA-SEMG showed that healthy individuals exhibit highly organized, symmetric back muscle activity patterns, suggesting an orderly recruitment of muscle fibers. In contrast, back muscle activity patterns in LBP patients are asymmetric or multifocal, suggesting lack of orderly muscle recruitment. LA-SEMG was also shown capable of

Are the hamstrings from the drive leg or landing leg more active in baseball pitchers? An electromyographic study.

Science.gov (United States)

Erickson, Brandon J; Zaferiou, Antonia; Chalmers, Peter N; Ruby, Deana; Malloy, Phillip; Luchetti, Timothy J; Verma, Nikhil N; Romeo, Anthony A

2017-11-01

Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among baseball players of all levels. There are several graft choices in performing UCLR, one of which is a hamstring (gracilis or semitendinosus) autograft. It is unclear whether the hamstring muscle from a pitcher's drive leg (ipsilateral side of the UCLR) or landing leg (contralateral side of the UCLR) is more active during the pitching motion. We hypothesized that the landing leg semitendinosus will be more electromyographically active than the drive leg. Healthy, elite male pitchers aged 16-21 years were recruited. Sixteen pitchers (average age, 17.6 ± 1.6 years; 67% threw right handed) underwent electromyographic analysis. Pitchers threw 5 fastballs at 100% effort from the wind-up with electromyographic analysis of every pitch. Activation of the semitendinosus and biceps femoris in both legs was compared within pitchers and between pitchers. Hamstring activity was higher in the drive leg than in the landing leg during each phase and in sum, although the difference was significant only during the double support phase (P = .021). On within-pitcher analysis, 10 of 16 pitchers had significantly more sum hamstring activity in the drive leg than in the landing leg, while only 4 of 16 had more activity in the landing leg (P = .043). During the baseball pitch, muscle activity of the semitendinosus was higher in the drive leg than in the landing leg in most pitchers. Surgeons performing UCLR using hamstring autograft should consider harvesting the graft from the pitcher's landing leg to minimize disruption to the athlete's pitching motion. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Reliability of surface electromyography timing parameters in gait in cervical spondylotic myelopathy.

LENUS (Irish Health Repository)

Malone, Ailish

2012-02-01

The aims of this study were to validate a computerised method to detect muscle activity from surface electromyography (SEMG) signals in gait in patients with cervical spondylotic myelopathy (CSM), and to evaluate the test-retest reliability of the activation times designated by this method. SEMG signals were recorded from rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG), during gait in 12 participants with CSM on two separate test days. Four computerised activity detection methods, based on the Teager-Kaiser Energy Operator (TKEO), were applied to a subset of signals and compared to visual interpretation of muscle activation. The most accurate method was then applied to all signals for evaluation of test-retest reliability. A detection method based on a combined slope and amplitude threshold showed the highest agreement (87.5%) with visual interpretation. With respect to reliability, the standard error of measurement (SEM) of the timing of RF, TA and MG between test days was 5.5% stride duration or less, while the SEM of BF was 9.4%. The timing parameters of RF, TA and MG designated by this method were considered sufficiently reliable for use in clinical practice, however the reliability of BF was questionable.

Multidimensional control using a mobile-phone based brain-muscle-computer interface.

Science.gov (United States)

Vernon, Scott; Joshi, Sanjay S

2011-01-01

Many well-known brain-computer interfaces measure signals at the brain, and then rely on the brain's ability to learn via operant conditioning in order to control objects in the environment. In our lab, we have been developing brain-muscle-computer interfaces, which measure signals at a single muscle and then rely on the brain's ability to learn neuromuscular skills via operant conditioning. Here, we report a new mobile-phone based brain-muscle-computer interface prototype for severely paralyzed persons, based on previous results from our group showing that humans may actively create specified power levels in two separate frequency bands of a single sEMG signal. Electromyographic activity on the surface of a single face muscle (Auricularis superior) is recorded with a standard electrode. This analog electrical signal is imported into an Android-based mobile phone. User-modulated power in two separate frequency band serves as two separate and simultaneous control channels for machine control. After signal processing, the Android phone sends commands to external devices via Bluetooth. Users are trained to use the device via biofeedback, with simple cursor-to-target activities on the phone screen.

Electromyographic analyses of muscle pre-activation induced by single joint exercise.

Science.gov (United States)

Júnior, Valdinar A R; Bottaro, Martim; Pereira, Maria C C; Andrade, Marcelino M; P Júnior, Paulo R W; Carmo, Jake C

2010-01-01

To investigate whether performing a low-intensity, single-joint exercises for knee extensors was an efficient strategy for increasing the number of motor units recruited in the vastus lateralis muscle during a subsequent multi-joint exercises. Nine healthy male participants (23.33+/-3.46 yrs) underwent bouts of exercise in which knee extension and 45 degrees , and leg press exercises were performed in sequence. In the low-intensity bout (R30), 15 unilateral knee extensions were performed, followed by 15 repetitions of the leg presses at 30% and 60% of one maximum repetition load (1-MR), respectively. In the high-intensity bout (R60), the same sequence was performed, but the applied load was 60% of 1-MR for both exercises. A single set of 15 repetitions of the leg press at 60% of 1-MR was performed as a control exercise (CR). The surface electromyographic signals of the vastus lateralis muscle were recorded by means of a linear electrode array. The root mean square (RMS) values were determined for each repetition of the leg press, and linear regressions were calculated from these results. The slopes of the straight lines obtained were then normalized using the linear coefficients of the regression equations and compared using one-way ANOVAs for repeated measures. The slopes observed in the CR were significantly lower than those in the R30 and R60 (precruitment of motor units was more effective when a single-joint exercise preceded the multi-joint exercise. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number ACTRN12609000413224.

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

Effects of treadmill inclination on electromyographic activity and hind limb kinematics in healthy hounds at a walk.

Science.gov (United States)

Lauer, Susanne K; Hillman, Robert B; Li, Li; Hosgood, Giselle L

2009-05-01

To evaluate the effect of treadmill incline on muscle activity and joint range of motion (ROM) in hind limbs of dogs. 8 purpose-bred healthy adult hounds. Activities of the hamstring (semimembranosus, semitendinosus, and biceps femoris muscles), gluteal (superficial, middle, and deep gluteal muscles), and quadriceps (femoris, vastus lateralis, vastus intermedius, and vastus medialis muscles) muscle groups and hip and stifle joint ROM were measured with surface electrogoniometric and myographic sensors in hounds walking on a treadmill at 0.54 m/s at inclines of 5%, 0%, and -5% in random order. Mean electromyographic activities and mean ROMs at each inclination were compared for swing and stance phases. Treadmill inclination did not affect duration of the stance and swing phases or the whole stride. When treadmill inclination was increased from -5% to 5%, hip joint ROM increased and the degree of stifle joint extension decreased significantly. In the beginning of the stance phase, activity of the hamstring muscle group was significantly increased when walking at a 5% incline versus a 5% decline. In the end of the stance phase, that activity was significantly increased when walking at a 5% incline versus at a 5% decline or on a flat surface. Activity of the gluteal and quadriceps muscle groups was not affected when treadmill inclination changed. Treadmill inclination affected joint kinematics only slightly. Walking on a treadmill at a 5% incline had more potential to strengthen the hamstring muscle group than walking on a treadmill with a flat or declined surface.

Fractal based complexity measure and variation in force during sustained isometric muscle contraction: effect of aging.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K; Bastos, Teodiano

2012-01-01

This study has investigated the effect of age on the fractal based complexity measure of muscle activity and variance in the force of isometric muscle contraction. Surface electromyogram (sEMG) and force of muscle contraction were recorded from 40 healthy subjects categorized into: Group 1: Young - age range 20-30; 10 Males and 10 Females, Group 2: Old - age range 55-70; 10 Males and 10 Females during isometric exercise at Maximum Voluntary contraction (MVC). The results show that there is a reduction in the complexity of surface electromyogram (sEMG) associated with aging. The results demonstrate that there is an increase in the coefficient of variance (CoV) of the force of muscle contraction and a decrease in complexity of sEMG for the Old age group when compared with the Young age group.

Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion

Directory of Open Access Journals (Sweden)

Alister du Rose

2016-01-01

Full Text Available Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF and surface electromyography (sEMG. Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES, Longissimus thoracis pars lumborum (LES, and Multifidus (LMU. Normalised root mean square (RMS sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = −0.47 to 0.59. The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = −0.53. The relationships found may be important when considering rehabilitation for low back pain.

Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion.

Science.gov (United States)

du Rose, Alister; Breen, Alan

2016-01-05

Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF) and surface electromyography (sEMG). Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES), Longissimus thoracis pars lumborum (LES), and Multifidus (LMU). Normalised root mean square (RMS) sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = -0.47 to 0.59). The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = -0.53). The relationships found may be important when considering rehabilitation for low back pain.

Electromyographic characteristic of orbicularis oris in patients with dental crowding in permanent occlusion.

Science.gov (United States)

Dmytrenko, Maryna I; Kuroiedowa, Vira D

2016-01-01

electromyographic indices were developed for complex analysis of functional condition of orbicularis oris. to study electromyographic indices of orbicularis oris in patients with dental crowding in permanent occlusion. thirty four patients with malocclusion and a severe degree of severity of dental crowding (15 males, 19 females, aged 16-29 years) who underwent orthodontic examination. The treatment group was divided into three: Group Ia comprised 11 subjects with mandibular crowding (mean age 19,27 ± 1,08 years); group Ib, 10 patients with maxillary dental crowding (mean age 20,10 ± 1,60 years) and group Ic, 13 subjects with both maxillary and mandibular crowding (mean age 20,15 ± 1,45 years). The control group consisted of 10 patients with malocclusions but without dental crowding (mean age 20,70 ± 1,32 years). The findings were compared with similar indices in subjects with normal occlusion (mean age 21,3 ± 1,25 years). The index of orbicularis oris activity (ACTIV,%) was determined for each patient. A Student's t-test was used to analyze statistical difference between different groups. patients having crowding of maxillary teeth showed greater activity of muscles of the upper lip during maximum voluntary clenching (АCTІV= -0,99±7,44%). Activity of the muscles of the lower lip in patients with crowding of mandibular teeth (АСTІV=20,52±4,22%) and crowding of maxillary and mandibular teeth (АСTІV=17,93±4,33%) is prevailing. аctivity of the orbicularis oris in patients with malocclusion, complicated by dental crowding depend on clinical localization of crowding.

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.

A COMPARATIVE-STUDY OF ELECTROMYOGRAMS OF THE MASSETER, TEMPORALIS, AND ANTERIOR DIGASTRIC MUSCLES OBTAINED BY SURFACE AND INTRAMUSCULAR ELECTRODES - RAW-EMG

NARCIS (Netherlands)

KOOLE, P; DEJONGH, HJ; BOERING, G

Electromyographic activity was synchronously recorded by surface and intramuscular electrodes in the same muscle. The activity of the left masseter, left temporalis, and both bellies of the anterior digastric muscle was studied by this double registration technique. In rest position no

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.

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)

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.

Assessing altered motor unit recruitment patterns in paretic muscles of stroke survivors using surface electromyography

Science.gov (United States)

Hu, Xiaogang; Suresh, Aneesha K.; Rymer, William Z.; Suresh, Nina L.

2015-12-01

Objective. The advancement of surface electromyogram (sEMG) recording and signal processing techniques has allowed us to characterize the recruitment properties of a substantial population of motor units (MUs) non-invasively. Here we seek to determine whether MU recruitment properties are modified in paretic muscles of hemispheric stroke survivors. Approach. Using an advanced EMG sensor array, we recorded sEMG during isometric contractions of the first dorsal interosseous muscle over a range of contraction levels, from 20% to 60% of maximum, in both paretic and contralateral muscles of stroke survivors. Using MU decomposition techniques, MU action potential amplitudes and recruitment thresholds were derived for simultaneously activated MUs in each isometric contraction. Main results. Our results show a significant disruption of recruitment organization in paretic muscles, in that the size principle describing recruitment rank order was materially distorted. MUs were recruited over a very narrow force range with increasing force output, generating a strong clustering effect, when referenced to recruitment force magnitude. Such disturbances in MU properties also correlated well with the impairment of voluntary force generation. Significance. Our findings provide direct evidence regarding MU recruitment modifications in paretic muscles of stroke survivors, and suggest that these modifications may contribute to weakness for voluntary contractions.

Clinical and electromyographic criteria for the diagnosis of hereditary myotonic syndromes

Directory of Open Access Journals (Sweden)

V. P. Fedotov

2012-01-01

Full Text Available Hereditary myotonic syndromes (HMS are a group of genetically heterogeneous diseases of the chlorine and sodium ion channels (channelopathies with evident clinical polymorphism and high prevalence in the population. The differential diagnosis of early‑stage NMS poses a challenge to clinicians to this day. The investigation has attempted to elaborate informative differentiating criteria on the basis of a clinical and electromyographic study of 2 groups of patients with hereditary Thomsen or Becker myotonia (n = 45 and myotonic dystrophy type 1 (n = 39 verified by DNA analysis of the CLCN1 and DMPK genes. Along with the clinical symptoms, there may be the value of M‑response amplitude decrement in rhythmic stimulation of the n. ulnaris and the duration of myotonic discharges at pin electromyography of the m. tibialis anterior.

Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects.

Science.gov (United States)

Cao, Liu; Wang, Ying; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Zheng, Dingchang

2017-01-01

The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF) magnetic stimulation on surface electromyography (SEMG) signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body) with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects). The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject's deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS), median frequency (MDF), and sample entropy (SampEn), were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant ( p 0.05). In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p < 0.001) and MDF and SampEn were significantly smaller (all p < 0.001).

Surface electromyography in orthodontics – a literature review

Science.gov (United States)

WoŸniak, Krzysztof; Piątkowska, Dagmara; Lipski, Mariusz; Mehr, Katarzyna

2013-01-01

Electromyography is the most objective and reliable technique for evaluating muscle function and efficiency by detecting their electrical potentials. It makes it possible to assess the extent and duration of muscle activity. The main aim of surface electromyography is to detect signals from many muscle fibers in the area of the detecting surface electrodes. These signals consist of a weighted summation of the spatial and temporal activity of many motor units. Hence, the analysis of the recordings is restricted to an assessment of general muscle activity, the cooperation of different muscles, and the variability of their activity over time. This study presents the main assumptions in the assessment of electrical muscle activity through the use of surface electromyography, along with its limitations and possibilities for further use in many areas of orthodontics. The main clinical uses of sEMG include the diagnostics and therapy of temporomandibular joint disorders, an assessment of the extent of stomatognathic system dysfunctions in subjects with malocclusion, and the monitoring of orthodontic therapies. PMID:23722255

Neuro-lepra: valor de la electromiografia Neuro-leprosy: electromyographic studies

Directory of Open Access Journals (Sweden)

Ernesto Herskovits

1971-09-01

Full Text Available Dada la frecuencia con que la lepra afecta al sistema nervioso, consideramos de interés realizar un estudio electromiográfico en zonas corporales clínicamente sanas. Hemos elegido para tal fin 14 enfermos que no tenían lesión sensitivo-motora clínicamente perceptible en el nervio cubital izquierdo. Hemos estudiado tambén un grupo de control de 5 enfermos con lesión evidente del mismo nervio. Se ha comprobado que de los 14 enfermos que aparentemente no tenían lesión del nervio cubital izquierdo, en 12 de ellos surgieron alteraciones electromiográficas que señalan la lesión del nervio, aunque en um grado menor que en el grupo de control. Este hecho nos hace pensar que la agresión que sufre el sistema nervioso periférico es de una extensión mayor que lo hace suponer la clínica, o que las lesiones anatómicas no retrogradan como nos lo sugiere el examen de los pacientes.Considering the frequency of the peripheral nervous system envolvement in leprosy 14 patients without clinical signs indicating impairment of the left ulnar nerve were submitted to electromyographic studies. All were chronic cases in which the disease had an evolution of three years for the most recent one, the longest during thirty one years. All patients were under leprosy treatment: nine had lepromatous leprosy, four had tuberculoid form, one had a dimorfous form. At the same time, as a control group, were studied 5 patients presenting clinical signis of injury of the left ulnar nerve. An electromiograph DISA with 3 channels, a Multistin estimulator and concentric electrodes were employed. In all the 19 cases the espontaneous activity, the type of recruiting reaction and the conduction velocity were analysed. Results were synthetized in Tables 1 and 2. The finding of electromyographic abnormalities in clinically healthy territores of 12/14 patients examined lead to the conclusion that in leprosy the agression to the peripheral nervous system is more extensive than

Estimating the progression of muscle fatigue based on dependence between motor units using high density surface electromyogram.

Science.gov (United States)

Bingham, Adrian; Arjunan, Sridhar P; Kumar, Dinesh K

2016-08-01

In this study we have tested the hypothesis regarding the increase in synchronization with the onset of muscle fatigue. For this aim, we have investigated the difference in the synchronicity between high density surface electromyogram (sEMG) channels of the rested muscles and when at the limit of endurance. Synchronization was measured by computing and normalizing the mutual information between the sEMG signals recorded from the high-density array electrode locations. Ten volunteers (Age range: 21 and 35 years; Mean age = 26 years; Male = 6, Female = 4) participated in our experiment. The participants performed isometric dorsiflexion of their dominate foot at two levels of contraction; 40% and 80% of their maximum voluntary contraction (MVC) until task failure. During the experiment an array of 64 electrodes (16 by 4) placed over the TA parallel to the muscle fiber was used to record the HD-sEMG. Normalized Mutual Information (NMI) between electrodes was calculated using the HD-sEMG data and then analyzed. The results show that that the average NMI of the TA significantly increased during fatigue at both levels of contraction. There was a statistically significant difference between NMI of the rested muscle compared with it being at the point of task failure.

Materials and optimized designs for human-machine interfaces via epidermal electronics.

Science.gov (United States)

Jeong, Jae-Woong; Yeo, Woon-Hong; Akhtar, Aadeel; Norton, James J S; Kwack, Young-Jin; Li, Shuo; Jung, Sung-Young; Su, Yewang; Lee, Woosik; Xia, Jing; Cheng, Huanyu; Huang, Yonggang; Choi, Woon-Seop; Bretl, Timothy; Rogers, John A

2013-12-17

Thin, soft, and elastic electronics with physical properties well matched to the epidermis can be conformally and robustly integrated with the skin. Materials and optimized designs for such devices are presented for surface electromyography (sEMG). The findings enable sEMG from wide ranging areas of the body. The measurements have quality sufficient for advanced forms of human-machine interface. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Evaluation of the electromyography activity of pelvic floor muscle during postural exercises using the Wii Fit Plus©. Analysis and perspectives in rehabilitation].

Science.gov (United States)

Steenstrup, B; Giralte, F; Bakker, E; Grise, P

2014-12-01

The aim of this work was to evaluate the effect of postural awareness by using the Wii Fit Plus© on the quality of the baseline (automatic) activity of the pelvic floor muscles (PFM) measured by intravaginal surface electromyography (sEMG). Four healthy continent female subjects, all able to perform a voluntary contraction, undertook 2 sets of 3 various exercises offered by the software Wii Fit Plus© using the Wii balance board© (WBB): one set without any visual control and the second set with postural control and sEMG visual feedback. Simultaneously, we recorded the sEMG activity of the PFM. Mean baseline activity of PFM in standing position at start was 2.87 mV, at submaximal voluntary contraction the sEMG activity raised at a mean of 14.43 mV (7.87-21.89). In the first set of exercises on the WBB without any visual feedback, the automatic activity of the PFM increased from 2.87 mV to 8.75 mV (7.96-9.59). In the second set, with visual postural and sEMG control, mean baseline sEMG activity even raised at 11.39 mV (10.17-11.58). Among women able of a voluntary contraction of PFM, visualisation of posture with the help of the WBB and of sEMG activity of the PFM during static and dynamic Wii Fit Plus© activities, may improve the automatic activation of the PFMs. 4. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Wireless electronic-tattoo for long-term high fidelity facial muscle recordings

Science.gov (United States)

Inzelberg, Lilah; David Pur, Moshe; Steinberg, Stanislav; Rand, David; Farah, Maroun; Hanein, Yael

2017-05-01

Facial surface electromyography (sEMG) is a powerful tool for objective evaluation of human facial expressions and was accordingly suggested in recent years for a wide range of psychological and neurological assessment applications. Owing to technical challenges, in particular the cumbersome gelled electrodes, the use of facial sEMG was so far limited. Using innovative facial temporary tattoos optimized specifically for facial applications, we demonstrate the use of sEMG as a platform for robust identification of facial muscle activation. In particular, differentiation between diverse facial muscles is demonstrated. We also demonstrate a wireless version of the system. The potential use of the presented technology for user-experience monitoring and objective psychological and neurological evaluations is discussed.

Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects

Directory of Open Access Journals (Sweden)

Liu Cao

2017-01-01

Full Text Available The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF magnetic stimulation on surface electromyography (SEMG signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject’s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS, median frequency (MDF, and sample entropy (SampEn, were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05. In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p<0.001 and MDF and SampEn were significantly smaller (all p<0.001.

Electromyographic Pattern Analysis and Classification for a Robotic Prosthetic Arm

Directory of Open Access Journals (Sweden)

M. José H. Erazo Macias

2006-01-01

Full Text Available This paper deals with the statistical analysis and pattern classification of electromyographic signals from the biceps of a person with amputation below the humerus. Such signals collected from an amputation simulator are synergistically generated to produce discrete elbow movements. The purpose of this study is to utilise these signals to control an electrically driven prosthetic or orthotic elbow with minimum extra mental effort on the part of the subject. The results show very good separability of classes of movements when a learning pattern classification scheme is used, and a superposition of any composite motion to the three basic primitive motions—humeral rotation in and out, flexion and extension, and pronation and supination. Since no synergy was detected for the wrist movement, different inputs have to be provided for a grip. In addition, the method described is not limited by the location of the electrodes. For amputees with shorter stumps, synergistic signals could be obtained from the shoulder muscles. However, the presentation in this paper is limited to biceps signal classification only.

Age-associated changes in muscle activity during isometric contraction.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K

2013-04-01

We investigated the effect of age on the complexity of muscle activity and the variance in the force of isometric contraction. Surface electromyography (sEMG) from biceps brachii muscle and force of contraction were recorded from 96 subjects (20-70 years of age) during isometric contractions. There was a reduction in the complexity of sEMG associated with aging. The relationship of age and complexity was approximated using a bilinear fit, with the average knee point at 45 years. There was an age-associated increase in the coefficient of variation (CoV) of the force of muscle contraction, and this increase was correlated with the decrease in complexity of sEMG (r(2) = 0.76). There was an age-associated increase in CoV and also a reduction in the complexity of sEMG. The correlation between these 2 factors can be explained based on the age-associated increase in motor unit density. Copyright © 2012 Wiley Periodicals, Inc.

Embroidered Electromyography: A Systematic Design Guide.

Science.gov (United States)

Shafti, Ali; Ribas Manero, Roger B; Borg, Amanda M; Althoefer, Kaspar; Howard, Matthew J

2017-09-01

Muscle activity monitoring or electromyography (EMG) is a useful tool. However, EMG is typically invasive, expensive and difficult to use for untrained users. A possible solution is textile-based surface EMG (sEMG) integrated into clothing as a wearable device. This is, however, challenging due to 1) uncertainties in the electrical properties of conductive threads used for electrodes, 2) imprecise fabrication technologies (e.g., embroidery, sewing), and 3) lack of standardization in design variable selection. This paper, for the first time, provides a design guide for such sensors by performing a thorough examination of the effect of design variables on sEMG signal quality. Results show that imprecisions in digital embroidery lead to a trade-off between low electrode impedance and high manufacturing consistency. An optimum set of variables for this trade-off is identified and tested with sEMG during a variable force isometric grip exercise with n = 12 participants, compared with conventional gel-based electrodes. Results show that thread-based electrodes provide a similar level of sensitivity to force variation as gel-based electrodes with about 90% correlation to expected linear behavior. As proof of concept, jogging leggings with integrated embroidered sEMG are made and successfully tested for detection of muscle fatigue while running on different surfaces.

Acute electromyographic responses of deep thoracic paraspinal muscles to spinal manual therapy interventions. An experimental, randomized cross-over study.

Science.gov (United States)

Fryer, Gary; Bird, Michael; Robbins, Barry; Johnson, Jane C

2017-07-01

This single group, randomized, cross-over study explored whether manual therapy alters motor tone of deep thoracic back muscles by examining resting electromyographic activity (EMG) after 2 types of manual therapy and a sham control intervention. Twenty-two participants with thoracic spinal pain (15 females, 7 males, mean age 28.1 ± 6.4 years) had dual fine-wire, intramuscular electrodes inserted into deep transversospinalis muscles at a thoracic level where tissues appeared abnormal to palpation (AbP) and at 2 sites above and below normal and non-tender to palpation (NT). A surface electrode was on the contralateral paraspinal mass at the level of AbP. EMG signals were recorded for resting prone, two 3-s free neck extension efforts, two 3-s resisted maximal voluntary isometric contractions (MVIC), and resting prone before the intervention. Randomized spinal manipulation, counterstrain, or sham manipulation was delivered and EMG re-measured. Participants returned 1 and 2 weeks later for the remaining 2 treatments. Reductions in resting EMG followed counterstrain in AbP (median decrease 3.3%, P = 0.01) and NT sites (median decrease 1.0%, P = 0.05) and for the surface electrode site (median decrease 2.0%, P = 0.009). Reduction in EMG following counterstrain during free neck extension was found for the surface electrode site (median decrease 2.7%, P < 0.01). Spinal manipulation produced no change in EMG, whereas counterstrain technique produced small significant reductions in paraspinal muscle activity during prone resting and free neck extension conditions. The clinical relevance of these changes is unclear. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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

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.

Changes in motor unit behavior following isometric fatigue of the first dorsal interosseous muscle

Science.gov (United States)

Rymer, William Z.; Lowery, Madeleine M.; Suresh, Nina L.

2015-01-01

The neuromuscular strategies employed to compensate for fatigue-induced muscle force deficits are not clearly understood. This study utilizes surface electromyography (sEMG) together with recordings of a population of individual motor unit action potentials (MUAPs) to investigate potential compensatory alterations in motor unit (MU) behavior immediately following a sustained fatiguing contraction and after a recovery period. EMG activity was recorded during abduction of the first dorsal interosseous in 12 subjects at 20% maximum voluntary contraction (MVC), before and directly after a 30% MVC fatiguing contraction to task failure, with additional 20% MVC contractions following a 10-min rest. The amplitude, duration and mean firing rate (MFR) of MUAPs extracted with a sEMG decomposition system were analyzed, together with sEMG root-mean-square (RMS) amplitude and median frequency (MPF). MUAP duration and amplitude increased immediately postfatigue and were correlated with changes to sEMG MPF and RMS, respectively. After 10 min, MUAP duration and sEMG MPF recovered to prefatigue values but MUAP amplitude and sEMG RMS remained elevated. MU MFR and recruitment thresholds decreased postfatigue and recovered following rest. The increase in MUAP and sEMG amplitude likely reflects recruitment of larger MUs, while recruitment compression is an additional compensatory strategy directly postfatigue. Recovery of MU MFR in parallel with MUAP duration suggests a possible role for metabolically sensitive afferents in MFR depression postfatigue. This study provides insight into fatigue-induced neuromuscular changes by examining the properties of a large population of concurrently recorded single MUs and outlines possible compensatory strategies involving alterations in MU recruitment and MFR. PMID:25761952

A Novel Phonology- and Radical-Coded Chinese Sign Language Recognition Framework Using Accelerometer and Surface Electromyography Sensors.

Science.gov (United States)

Cheng, Juan; Chen, Xun; Liu, Aiping; Peng, Hu

2015-09-15

Sign language recognition (SLR) is an important communication tool between the deaf and the external world. It is highly necessary to develop a worldwide continuous and large-vocabulary-scale SLR system for practical usage. In this paper, we propose a novel phonology- and radical-coded Chinese SLR framework to demonstrate the feasibility of continuous SLR using accelerometer (ACC) and surface electromyography (sEMG) sensors. The continuous Chinese characters, consisting of coded sign gestures, are first segmented into active segments using EMG signals by means of moving average algorithm. Then, features of each component are extracted from both ACC and sEMG signals of active segments (i.e., palm orientation represented by the mean and variance of ACC signals, hand movement represented by the fixed-point ACC sequence, and hand shape represented by both the mean absolute value (MAV) and autoregressive model coefficients (ARs)). Afterwards, palm orientation is first classified, distinguishing "Palm Downward" sign gestures from "Palm Inward" ones. Only the "Palm Inward" gestures are sent for further hand movement and hand shape recognition by dynamic time warping (DTW) algorithm and hidden Markov models (HMM) respectively. Finally, component recognition results are integrated to identify one certain coded gesture. Experimental results demonstrate that the proposed SLR framework with a vocabulary scale of 223 characters can achieve an averaged recognition accuracy of 96.01% ± 0.83% for coded gesture recognition tasks and 92.73% ± 1.47% for character recognition tasks. Besides, it demonstrats that sEMG signals are rather consistent for a given hand shape independent of hand movements. Hence, the number of training samples will not be significantly increased when the vocabulary scale increases, since not only the number of the completely new proposed coded gestures is constant and limited, but also the transition movement which connects successive signs needs no

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

Directory of Open Access Journals (Sweden)

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.

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.

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

Science.gov (United States)

Erdag, Deniz

2017-01-01

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 squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk. PMID:28546738

Gestures recognition based on wavelet and LLE

International Nuclear Information System (INIS)

Ai, Qingsong; Liu, Quan; Lu, Ying; Yuan, Tingting

2013-01-01

Wavelet analysis is a time–frequency, non-stationary method while the largest Lyapunov exponent (LLE) is used to judge the non-linear characteristic of systems. Because surface electromyography signal (SEMGS) is a complex signal that is characterized by non-stationary and non-linear properties. This paper combines wavelet coefficient and LLE together as the new feature of SEMGS. The proposed method not only reflects the non-stationary and non-linear characteristics of SEMGS, but also is suitable for its classification. Then, the BP (back propagation) neural network is employed to implement the identification of six gestures (fist clench, fist extension, wrist extension, wrist flexion, radial deviation, ulnar deviation). The experimental results indicate that based on the proposed method, the identification of these six gestures can reach an average rate of 97.71 %.

Electromyography Activation Levels of the 3 Gluteus Medius Subdivisions During Manual Strength Testing

DEFF Research Database (Denmark)

Otten, Roald; Tol, Johannes L; Holmich, Per

2015-01-01

deficits and guide specific rehabilitation programs. However, the optimal positions for assessing the strength and activation of these subdivisions are unknown. OBJECTIVE: The first aim was to establish which strength-testing positions produce the highest surface electromyography (sEMG) activation levels...... of the individual GM subdivisions. The second aim was to evaluate differences in sEMG activation levels between the tested and contralateral (stabilizing) leg. METHOD: Twenty healthy physically active male subjects participated in this study. Muscle activity using sEMG was recorded for the GM subdivisions in 8......STUDY DESIGN: Cross-sectional. CONTEXT: Gluteus medius (GM) muscle dysfunction is associated with overuse injury. The GM is functionally composed of 3 separate subdivisions: anterior, middle, and posterior. Clinical assessment of the GM subdivisions is relevant to detect strength and activation...

Which nerve conduction parameters can predict spontaneous electromyographic activity in carpal tunnel syndrome?

Science.gov (United States)

Chang, Chia-Wei; Lee, Wei-Ju; Liao, Yi-Chu; Chang, Ming-Hong

2013-11-01

We investigate electrodiagnostic markers to determine which parameters are the best predictors of spontaneous electromyographic (EMG) activity in carpal tunnel syndrome (CTS). We enrolled 229 patients with clinically proven and nerve conduction study (NCS)-proven CTS, as well as 100 normal control subjects. All subjects were evaluated using electrodiagnostic techniques, including median distal sensory latencies (DSLs), sensory nerve action potentials (SNAPs), distal motor latencies (DMLs), compound muscle action potentials (CMAPs), forearm median nerve conduction velocities (FMCVs) and wrist-palm motor conduction velocities (W-P MCVs). All CTS patients underwent EMG examination of the abductor pollicis brevis (APB) muscle, and the presence or absence of spontaneous EMG activities was recorded. Normal limits were determined by calculating the means ± 2 standard deviations from the control data. Associations between parameters from the NCS and EMG findings were investigated. In patients with clinically diagnosed CTS, abnormal median CMAP amplitudes were the best predictors of spontaneous activity during EMG examination (p95% (positive predictive rate >95%). If the median CMAP amplitude was higher than the normal limit (>4.9 mV), the rate of no spontaneous EMG activity was >94% (negative predictive rate >94%). An abnormal SNAP amplitude was the second best predictor of spontaneous EMG activity (p<0.001; OR 4.13; 95% CI 2.16-7.90), and an abnormal FMCV was the third best predictor (p=0.01; OR 2.10; 95% CI 1.20-3.67). No other nerve conduction parameters had significant power to predict spontaneous activity upon EMG examination. The CMAP amplitudes of the APB are the most powerful predictors of the occurrence of spontaneous EMG activity. Low CMAP amplitudes are strongly associated with spontaneous activity, whereas high CMAP amplitude are less associated with spontaneous activity, implying that needle EMG examination should be recommended for the detection of

Electromyographic study of the upper extremity during bilateral sanding: unresisted and resisted conditions.

Science.gov (United States)

Spaulding, S J; Robinson, K L

1984-04-01

Electromyographic information was obtained from seven right shoulder complex muscles in nine subjects (three normal, three paraplegic, and three quadriplegic) during the occupational therapy activity of bilateral sanding on an incline board, an activity that has been recommended as a treatment modality to strengthen the triceps brachii. Electromyography revealed that the anterior and middle portions of the deltoid were the muscles most responsible for the subjects' arm movements during both resisted and unresisted bilateral sanding . Triceps lateralis and medialis were also active during the up phase, but not as consistently as the deltoid. Pectoralis major and biceps brachii were not extensively active in most subjects. The small size and heterogeneity of the subject sample limits the generalizations of our findings. However, graded resisted bilateral sanding does appear to be an appropriate activity for strengthening the shoulder muscle group, especially the deltoid and triceps brachii, in the tested patient populations.

Assessing the Therapeutic Effect of 630 nm Light-Emitting Diodes Irradiation on the Recovery of Exercise-Induced Hand Muscle Fatigue with Surface Electromyogram

Directory of Open Access Journals (Sweden)

Dandan Yang

2012-01-01

Full Text Available This paper aims to investigate the effect of light emitting diode therapy (LEDT on exercise-induced hand muscle fatigue by measuring the surface electromyography (sEMG of flexor digitorum superficialis. Ten healthy volunteers were randomly placed in the equal sized LEDT group and control group. All subjects performed a sustained fatiguing isometric contraction with the combination of four fingertips except thumb at 30% of maximal voluntary contraction (MVC until exhaustion. The active LEDT or an identical passive rest therapy was then applied to flexor digitorum superficialis. Each subject was required to perform a re-fatigue task immediately after therapy which was the same as the pre-fatigue task. Average rectified value (ARV and fractal dimension (FD of sEMG were calculated. ARV and FD were significantly different between active LEDT and passive rest groups at 20%–50%, 70%–80%, and 100% of normalized contraction time (P<0.05. Compared to passive rest, active LEDT induced significantly smaller increase in ARV values and decrease in FD values, which shows that LEDT is effective on the recovery of muscle fatigue. Our preliminary results also suggest that ARV and FD are potential replacements of biochemical markers to assess the effects of LEDT on muscle fatigue.

Robust Features Of Surface Electromyography Signal

Science.gov (United States)

Sabri, M. I.; Miskon, M. F.; Yaacob, M. R.

2013-12-01

Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20-27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and show

Robust Features Of Surface Electromyography Signal

International Nuclear Information System (INIS)

Sabri, M I; Miskon, M F; Yaacob, M R

2013-01-01

Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20–27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and

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.

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

Tennis Elbow Diagnosis Using Equivalent Uniform Voltage to Fit the Logistic and the Probit Diseased Probability Models

Directory of Open Access Journals (Sweden)

Tsair-Fwu Lee

2015-01-01

Full Text Available To develop the logistic and the probit models to analyse electromyographic (EMG equivalent uniform voltage- (EUV- response for the tenderness of tennis elbow. In total, 78 hands from 39 subjects were enrolled. In this study, surface EMG (sEMG signal is obtained by an innovative device with electrodes over forearm region. The analytical endpoint was defined as Visual Analog Score (VAS 3+ tenderness of tennis elbow. The logistic and the probit diseased probability (DP models were established for the VAS score and EMG absolute voltage-time histograms (AVTH. TV50 is the threshold equivalent uniform voltage predicting a 50% risk of disease. Twenty-one out of 78 samples (27% developed VAS 3+ tenderness of tennis elbow reported by the subject and confirmed by the physician. The fitted DP parameters were TV50 = 153.0 mV (CI: 136.3–169.7 mV, γ50 = 0.84 (CI: 0.78–0.90 and TV50 = 155.6 mV (CI: 138.9–172.4 mV, m = 0.54 (CI: 0.49–0.59 for logistic and probit models, respectively. When the EUV ≥ 153 mV, the DP of the patient is greater than 50% and vice versa. The logistic and the probit models are valuable tools to predict the DP of VAS 3+ tenderness of tennis elbow.

Tennis Elbow Diagnosis Using Equivalent Uniform Voltage to Fit the Logistic and the Probit Diseased Probability Models

Science.gov (United States)

Lin, Wei-Chun; Lin, Shu-Yuan; Wu, Li-Fu; Guo, Shih-Sian; Huang, Hsiang-Jui; Chao, Pei-Ju

2015-01-01

To develop the logistic and the probit models to analyse electromyographic (EMG) equivalent uniform voltage- (EUV-) response for the tenderness of tennis elbow. In total, 78 hands from 39 subjects were enrolled. In this study, surface EMG (sEMG) signal is obtained by an innovative device with electrodes over forearm region. The analytical endpoint was defined as Visual Analog Score (VAS) 3+ tenderness of tennis elbow. The logistic and the probit diseased probability (DP) models were established for the VAS score and EMG absolute voltage-time histograms (AVTH). TV50 is the threshold equivalent uniform voltage predicting a 50% risk of disease. Twenty-one out of 78 samples (27%) developed VAS 3+ tenderness of tennis elbow reported by the subject and confirmed by the physician. The fitted DP parameters were TV50 = 153.0 mV (CI: 136.3–169.7 mV), γ 50 = 0.84 (CI: 0.78–0.90) and TV50 = 155.6 mV (CI: 138.9–172.4 mV), m = 0.54 (CI: 0.49–0.59) for logistic and probit models, respectively. When the EUV ≥ 153 mV, the DP of the patient is greater than 50% and vice versa. The logistic and the probit models are valuable tools to predict the DP of VAS 3+ tenderness of tennis elbow. PMID:26380281

Electromyographically Assessed Empathic Concern and Empathic Happiness Predict Increased Prosocial Behavior in Adults

Science.gov (United States)

Light, Sharee N.; Moran, Zachary D.; Swander, Lena; Le, Van; Cage, Brandi; Burghy, Cory; Westbrook, Cecilia; Greishar, Larry; Davidson, Richard J.

2016-01-01

The relation between empathy subtypes and prosocial behavior was investigated in a sample of healthy adults. "Empathic concern" and "empathic happiness," defined as negative and positive vicarious emotion (respectively) combined with an other-oriented feeling of “goodwill” (i.e. a thought to do good to others/see others happy), were elicited in 68 adult participants who watched video clips extracted from the television show Extreme Makeover: Home Edition. Prosocial behavior was quantified via performance on a non-monetary altruistic decision-making task involving book selection and donation. Empathic concern and empathic happiness were measured via self-report (immediately following each video clip) and via facial electromyography recorded from corrugator (active during frowning) and zygomatic (active during smiling) facial regions. Facial electromyographic signs of (a) empathic concern (i.e. frowning) during sad video clips, and (b) empathic happiness (i.e. smiling) during happy video clips, predicted increased prosocial behavior in the form of increased goodwill-themed book selection/donation. PMID:25486408

Electromyographic Activity of Shoulder Girdle Muscles in Patients With Symptomatic and Asymptomatic Rotator Cuff Tears: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Spall, Peter; Ribeiro, Daniel Cury; Sole, Gisela

2016-09-01

To compare electromyographic activity in patients with symptomatic rotator cuff tears with healthy controls or to those with asymptomatic cuff tears. TYPE: Systematic review and meta-analysis. PubMed, Scopus, Ovid Medline, and Web of Science were searched from inception to August 1, 2014, and a search update was performed on June 8, 2015. Case-control studies or intervention studies that had baseline comparisons for symptomatic versus healthy shoulders or those with asymptomatic rotator cuff tear were searched. Methodological quality was assessed with a modified Critical Appraisal Skills Programme score and meta-analyses were performed when 2 or more studies explored the same outcome measures. Nine studies were included, with the quality ranging from 1 to 3 (maximum 6). Electromyographic outcomes included amplitudes and ratios thereof, activity duration, and median frequency of shoulder girdle muscles during isometric contractions (4 studies) and functional tasks (5 studies). Longer activity duration was found for upper trapezius during glenohumeral movements, and greater fatigability of anterior and middle deltoids during isometric hand gripping for patients with rotator cuff tears compared to controls. The meta-analysis (3 studies) showed that patients with rotator cuff tears had lower activation ratios for latissimus dorsi during isometric abduction contraction compared to controls (P muscle activity differences between the rotator cuff tear group and controls is thus limited. Copyright © 2016. Published by Elsevier Inc.

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.

A comparative analysis of three non-invasive Human-Machine Interfaces for the disabled

Directory of Open Access Journals (Sweden)

Vikram eRavindra

2014-10-01

Full Text Available In the framework of rehabilitation robotics, a major role is played by theHuman-Machine Interface (HMI used to gather the patient's intent from biologicalsignals, and convert them into control signals for the robotic artifact. Surprisingly,decades of research haven't yet declared what the optimal HMI is in this context;in particular, the traditional approach based upon surface electromyography (sEMGstill yields unreliable results due to the inherent variability of the signal. Toovercome this problem, the scientific community has recently been advocating thediscovery, analysis and usage of novel HMIs to supersede or augment sEMG; a comparativeanalysis of such HMIs is therefore a very desirable investigation.In this paper we compare three such HMIs employed in the detection of finger forces,namely sEMG, ultrasound imaging and pressure sensing. The comparison is performed alongfour main lines: the accuracy in the prediction, the stability over time, the wearabilityand the cost. A psychophysical experiment involving ten intact subjects engaged ina simple finger-flexion task was set up. Our results show that, at least in thisexperiment, pressure sensing and sEMG yield comparably good prediction accuraciesas opposed to ultrasound imaging; and that pressure sensing enjoys a much better stabilitythan sEMG.Given that pressure sensors are as wearable as sEMG electrodes but way cheaper, we claimthat this HMI could represent a valid alternative /augmentation to sEMG to control amulti-fingered hand prosthesis.

Comparison of Electromyographic Activity Pattern of Knee Two-Joint Muscles between Youngs and Olders in Gait Different Speeds

Directory of Open Access Journals (Sweden)

Hamideh Khodaveisi

2016-01-01

Full Text Available Objective: In recent years, it has been focused much attention on gait analysis. Factors such as speed, age and gender affect gait parameters. The purpose of the present study was to compare the electromyographic activity pattern of knee two-joint muscles between younger and older subjects in different gait speeds. Matterials & Methods: The method of current study was analytical cross-sectional method in which 15 healthy young men and 15 old men, were selected conveniently. Electromyographic activity of rectus femoris, biceps femoris, semitendinus and gastrocenemius were recorded during walking with preferred (100%, slow (80% and fast (120% speeds in a 10 meter walkway. Normalized RMSs of muscles were compared using RM-ANOVA and Tokey’s tests by SPSS 18 software. Results: According to results, RMSs of rectus femoris in midstance (P<0.01 and gastrocenemius in loading response (P=0.02 phases in all walking speeds were higher in older subjects than in younger ones, and it increased with speed in both age groups (P<0.01. Biceps femoris RMS in terminal stance at 80% speed, was lower in older subjects than in younger ones (P=0.01 and it increased with walking speed (P=0.01. Semitendinus activity in loading and midstance phases at 120% speed was higher in older subjects than in younger ones (P<0.01, and it increased with speed in both age groups in swing phase (P<0.05. Conclusion: According to the results, older subjects have more muscle co-contraction around knee at high speed in midstance phase than younger subjects. These age-related changes in muscle activity, leads to increase in joint stiffness and stability during single support, and probably play a role in reducing push off power at faster speeds.

Abdominal crunch exercise analysis performed with maximum and submaximum loads: An electromyographic study

Directory of Open Access Journals (Sweden)

M.L. Moura

2011-01-01

Full Text Available The purpose of this study was to verify the electromyographic activity of the rectus abdominis and obliquus externus abdominis during abdominal crunch exercise performed with maximum and submaximum loads. Thirteen male and female university students participated in this investigation (18-23 years old. The subjects completed abdominal crunch exercise until exhaustion with 20, 40, 60 and 80% of the maximum load. The root-mean-square (RMS from electromyography activity of the rectus abdominis and obliquus externus muscles from the first and last three repetitions from each workload performed was analyzed. RMS for the last repetitions increased in relation to the first repetitions for the 20% workload, first two repetitions on 40% workload and first repetition on the 80% workload. There was no difference for the 60% workload. Results showed that external load on abdominal crunch exercise might be an alternative to increase intensity while performing abdominal crunch exercise, which on its turn can be a practical tool for subjects that aim to increase abdominal strength level.

Assessment of early onset of driver fatigue using multimodal fatigue measures in a static simulator.

Science.gov (United States)

Jagannath, M; Balasubramanian, Venkatesh

2014-07-01

Driver fatigue is an important contributor to road accidents. This paper reports a study that evaluated driver fatigue using multimodal fatigue measures, i.e., surface electromyography (sEMG), electroencephalography (EEG), seat interface pressure, blood pressure, heart rate and oxygen saturation level. Twenty male participants volunteered in this study by performing 60 min of driving on a static simulator. Results from sEMG showed significant physical fatigue (ρ fatigue. This will help us understand the influence of physical and mental fatigue on driver during monotonous driving. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Monitorando a deglutição através da eletromiografia de superfície Monitoring swallowing with surface electromyography

Directory of Open Access Journals (Sweden)

Maria das Graças Wanderley de Sales Coriolano

2010-06-01

Full Text Available OBJETIVO: descrever o método de registro da eletromiografia de superfície através da utilização de um protocolo desenvolvido para o estudo da deglutição e demonstrar a deglutição de um paciente com doença de Parkinson e de um sujeito normal através do registro da eletromiografia de superfície (EMGs. MÉTODOS: para ilustrar os parâmetros eletrofisiológicos registrados após execução do protocolo foram utilizados dois voluntários do sexo feminino, sendo um sem doença e outro apresentando doença de Parkinson (DP no estágio III de acordo com a escala de Hoehn e Yahr. Os parâmetros analisados pelo foram: a duração da atividade elétrica durante a deglutição, a amplitude (rms e o limite de disfagia. RESULTADOS: os resultados mostram diferenças entre os eletromiogramas ilustrativos. CONCLUSÃO: a EMGs pode ser utilizada como método de avaliação e monitorização da deglutição de sujeitos sem doença e com DP.PURPOSE: to describe the registering method of the surface electromyography (sEMG through the use of a protocol developed for swallowing study and to demonstrate the swallowing pattern of a patient with Parkinson’s disease and of normal individuals through the sEMG registering. METHODS: to illustrate the registered electrophysiologic parameters execution of the protocol we used two volunteers of the feminine gender, being one without disease and the other one with Parkinson’s disease (PD in III period of training in accordance with the scale of Hoehn and Yahr. The analyzed parameters had been the duration of the electric activity during swallowing, the amplitude (rms and the dysphagia limit. RESULTS: the results show differences amongst the illustrative electromyograms. CONCLUSION: sEMG can be used as method for evaluating and monitoring the swallowing pattern of citizens with no disease and with PD.

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.

Clinical and computerized evaluation in study of temporo-mandibular joint intracapsular disease.

Science.gov (United States)

Ciavarella, D; Mastrovincenzo, M; Sabatucci, A; Parziale, V; Granatelli, F; Violante, F; Bossù, M; Lo Muzio, L; Chimenti, C

2010-03-01

In this work authors show a diagnostic criteria in study of TMID: neuro occlusal clinical evaluation (NOE), T-Scan 2 system and surface electromyography (sEMG). Nine patients 25-30 years old with TMID problem and 9 healthy group control have been selected and examined. On each patients it has been performed NOE, T-Scan and sEMG test. NOE has been calculated on each patient photos lateral mandibular excursion angle called: masticatory functional angle (AFM). T-Scan System is a computerized occlusal analyzer that provide in-depth understanding of the overall balance of the occlusion. At the same time of T-Scan record sEMG tests, in resting position and in maximum clench, have been performed. In healthy control there were no AFM difference. In no healthy group there were difference between the two AFM greater than 6 degrees. T-Scan COF showed how in healthy group control there was never a difference of COF greater than 5%. In no healthy group the difference were greater than 5% Pjoint sound than the balance side P<0.001. sEMG show how in TMID patients maximum masseter activation is always lower than maximum masseter activation of healthy subjects P<0.001. Neuro occlusal clinical evaluation (NOE) in TMID patients is supported by instrumental evaluation.

The Evaluation of Bioelectrical Activity of Pelvic Floor Muscles Depending on Probe Location: A Pilot Study

Directory of Open Access Journals (Sweden)

Tomasz Halski

2013-01-01

Full Text Available Objectives. The main objective was to determine how the depth of probe placement affects functional and resting bioelectrical activity of the PFM and whether the recorded signal might be dependent on the direction in which the probe is rotated. Participants. The study comprised of healthy, nulliparous women between the ages of 21 and 25. Outcome Measures. Bioelectric activity of the PFM was recorded from four locations of the vagina by surface EMG and vaginal probe. Results. There were no statistically significant differences between the results during functional sEMG activity. During resting sEMG activity, the highest bioelectrical activity of the PFM was observed in the L1 and the lowest in the L4 and a statistically significant difference between the highest and the lowest results of resting sEMG activity was observed (P=0.0043. Conclusion. Different electrodes placement during functional contraction of PFM does not affect the obtained results in sEMG evaluation. In order to diagnose the highest resting activity of PFM the recording plates should be placed toward the anterior vaginal wall and distally from the introitus. However, all of the PFM have similar bioelectrical activity and it seems that these muscles could be treated as a single muscle.

Evaluation of Bioelectrical Activity of Pelvic Floor Muscles and Synergistic Muscles Depending on Orientation of Pelvis in Menopausal Women with Symptoms of Stress Urinary Incontinence: A Preliminary Observational Study

Directory of Open Access Journals (Sweden)

Tomasz Halski

2014-01-01

Full Text Available Objectives. Evaluation of resting and functional bioelectrical activity of the pelvic floor muscles (PFM and the synergistic muscles, depending on the orientation of the pelvis, in anterior (P1 and posterior (P2 pelvic tilt. Design. Preliminary, prospective observational study. Setting. Department and Clinic of Urology, University Hospital in Wroclaw, Poland. Participants. Thirty-two menopausal and postmenopausal women with stress urinary incontinence were recruited. Based on inclusion and exclusion criteria, sixteen women aged 55 to 70 years were enrolled in the study. Primary Outcome Measures. Evaluation of resting and functional bioelectrical activity of the pelvic floor muscles by electromyography (sEMG and vaginal probe. Secondary Outcome Measures. Evaluation of activity of the synergistic muscles by sEMG and surface electrodes. Results. No significant differences between orientations P1 and P2 were found in functional and resting sEMG activity of the PFM. During resting and functional PFM activity, higher electrical activity in P2 than in P1 has been recorded in some of the synergistic muscles. Conclusions. This preliminary study does not provide initial evidence that pelvic tilt influences PFM activation. Although different activity of synergistic muscles occurs in various orientations of the pelvic tilt, it does not have to affect the sEMG activity of the PFM.

Muscle activity in sprinting: a review.

Science.gov (United States)

Howard, Róisín M; Conway, Richard; Harrison, Andrew J

2018-03-01

The use of electromyography (EMG) is widely recognised as a valuable tool for enhancing the understanding of performance drivers and potential injury risk in sprinting. The timings of muscle activations relative to running gait cycle phases and the technology used to obtain muscle activation data during sprinting are of particular interest to scientists and coaches. This review examined the main muscles being analysed by surface EMG (sEMG), their activations and timing, and the technologies used to gather sEMG during sprinting. Electronic databases were searched using 'Electromyography' OR 'EMG' AND 'running' OR 'sprinting'. Based on inclusion criteria, 18 articles were selected for review. While sEMG is widely used in biomechanics, relatively few studies have used sEMG in sprinting due to system constraints. The results demonstrated a focus on the leg muscles, with over 70% of the muscles analysed in the upper leg. This is consistent with the use of tethered and data logging EMG systems and many sprints being performed on treadmills. Through the recent advances in wireless EMG technology, an increase in the studies on high velocity movements such as sprinting is expected and this should allow practitioners to perform the analysis in an ecologically valid environment.

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

Directory of Open Access Journals (Sweden)

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.

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.

Fractal based modelling and analysis of electromyography (EMG) to identify subtle actions.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K

2007-01-01

The paper reports the use of fractal theory and fractal dimension to study the non-linear properties of surface electromyogram (sEMG) and to use these properties to classify subtle hand actions. The paper reports identifying a new feature of the fractal dimension, the bias that has been found to be useful in modelling the muscle activity and of sEMG. Experimental results demonstrate that the feature set consisting of bias values and fractal dimension of the recordings is suitable for classification of sEMG against the different hand gestures. The scatter plots demonstrate the presence of simple relationships of these features against the four hand gestures. The results indicate that there is small inter-experimental variation but large inter-subject variation. This may be due to differences in the size and shape of muscles for different subjects. The possible applications of this research include use in developing prosthetic hands, controlling machines and computers.

A Pilot Study of Individual Muscle Force Prediction during Elbow Flexion and Extension in the Neurorehabilitation Field

Directory of Open Access Journals (Sweden)

Jiateng Hou

2016-11-01

Full Text Available This paper proposes a neuromusculoskeletal (NMS model to predict individual muscle force during elbow flexion and extension. Four male subjects were asked to do voluntary elbow flexion and extension. An inertial sensor and surface electromyography (sEMG sensors were attached to subject's forearm. Joint angle calculated by fusion of acceleration and angular rate using an extended Kalman filter (EKF and muscle activations obtained from the sEMG signals were taken as the inputs of the proposed NMS model to determine individual muscle force. The result shows that our NMS model can predict individual muscle force accurately, with the ability to reflect subject-specific joint dynamics and neural control solutions. Our method incorporates sEMG and motion data, making it possible to get a deeper understanding of neurological, physiological, and anatomical characteristics of human dynamic movement. We demonstrate the potential of the proposed NMS model for evaluating the function of upper limb movements in the field of neurorehabilitation.

A Methodological Approach to Quantifying Plyometric Intensity.

Science.gov (United States)

Jarvis, Mark M; Graham-Smith, Phil; Comfort, Paul

2016-09-01

Jarvis, MM, Graham-Smith, P, and Comfort, P. A Methodological approach to quantifying plyometric intensity. J Strength Cond Res 30(9): 2522-2532, 2016-In contrast to other methods of training, the quantification of plyometric exercise intensity is poorly defined. The purpose of this study was to evaluate the suitability of a range of neuromuscular and mechanical variables to describe the intensity of plyometric exercises. Seven male recreationally active subjects performed a series of 7 plyometric exercises. Neuromuscular activity was measured using surface electromyography (SEMG) at vastus lateralis (VL) and biceps femoris (BF). Surface electromyography data were divided into concentric (CON) and eccentric (ECC) phases of movement. Mechanical output was measured by ground reaction forces and processed to provide peak impact ground reaction force (PF), peak eccentric power (PEP), and impulse (IMP). Statistical analysis was conducted to assess the reliability intraclass correlation coefficient and sensitivity smallest detectable difference of all variables. Mean values of SEMG demonstrate high reliability (r ≥ 0.82), excluding ECC VL during a 40-cm drop jump (r = 0.74). PF, PEP, and IMP demonstrated high reliability (r ≥ 0.85). Statistical power for force variables was excellent (power = 1.0), and good for SEMG (power ≥0.86) excluding CON BF (power = 0.57). There was no significant difference (p > 0.05) in CON SEMG between exercises. Eccentric phase SEMG only distinguished between exercises involving a landing and those that did not (percentage of maximal voluntary isometric contraction [%MVIC] = no landing -65 ± 5, landing -140 ± 8). Peak eccentric power, PF, and IMP all distinguished between exercises. In conclusion, CON neuromuscular activity does not appear to vary when intent is maximal, whereas ECC activity is dependent on the presence of a landing. Force characteristics provide a reliable and sensitive measure enabling precise description of intensity

Assessment of electromyographic activity in patients with temporomandibular disorders and natural mediotrusive occlusal contact during chewing and tooth grinding.

Science.gov (United States)

Fuentes, Aler D; Sforza, Chiarella; Miralles, Rodolfo; Ferreira, Cláudia L; Mapelli, Andrea; Lodetti, Gianluigi; Martin, Conchita

2017-05-01

The aim of this study was to investigate whether the presence of a natural mediotrusive contact influences electromyographic (EMG) pattern activity in patients with temporomandibular disorders (TMDs). Bilateral surface EMG activity of the anterior temporalis (AT), masseter (MM), and sternocleidomastoid (SCM) muscles was recorded in 43 subjects during unilateral chewing and tooth grinding. Thirteen patients had TMD and a natural mediotrusive contact (Group 1), 15 had TMD without a natural mediotrusive contact (Group 2), and 15 were healthy subjects without mediotrusive contacts (Group 3). All subjects were examined according to the Research Diagnostic Criteria for TMD (RDC/TMD). All EMG values were standardized as the percentage of EMG activity recorded during maximum isometric contraction on cotton rolls. EMG activity from all muscles measured showed no significant differences between groups during chewing and grinding. Overall, in all groups, the EMG activity during chewing was higher in the working side than the non-working side in AT and MM muscles. During grinding, these differences were only found in masseter muscles (mainly in eccentric grinding). SCM EMG activity did not show significant differences during chewing and grinding tasks. Symmetry, muscular balance, and absence of lateral jaw displacement were common findings in all groups. EMG results suggest that the contribution of a natural mediotrusive occlusal contact to EMG patterns in TMD patients is minor. Therefore, the elimination of this occlusal feature for therapeutic purposes could be not indicated.

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.

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

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...

Differential contributions of ankle plantarflexors during submaximal isometric muscle action

DEFF Research Database (Denmark)

Masood, Tahir; Bojsen-Møller, Jens; Kalliokoski, Kari K

2014-01-01

The objective of this study was to investigate the relative contributions of superficial and deep ankle plantarflexors during repetitive submaximal isometric contractions using surface electromyography (SEMG) and positron emission tomography (PET). Myoelectric signals were obtained from twelve...

Evaluation of the immediate effect of acupuncture on pain, cervical range of motion and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain: study protocol for a randomized controlled trial.

Science.gov (United States)

Calamita, Simone Aparecida Penimpedo; Biasotto-Gonzalez, Daniela Aparecida; De Melo, Nivea Cristina; dos Santos, Douglas Meira; de Lassa, Roberta; de Mendonça, Fabiana Sarilho; Oliveira, Claudia Santos; Amorim, César Ferreira; Gonzalez, Tabajara Oliveira; Fumagalli, Marco Antônio; de Gomes, Cid André Fidelis Paula; Politti, Fabiano

2015-03-19

Nonspecific neck pain can cause considerable suffering, possible disability and reductions in quality of life and productivity. The aim of the proposed study is to evaluate the immediate effect of acupuncture on pain, cervical range of motion and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain. A total of 12 patients with nonspecific neck pain and 12 healthy subjects will be enrolled in a randomized, single-blind crossover study. Each subject will receive two forms of treatment in random order: a single session of traditional acupuncture (acupoints: triple energizer 5, 'Wai-guan' and large intestine 11, 'Qu-chi') and sham acupuncture. To eliminate carry-over treatment effects, a one-week wash-out period will be respected between sessions. Surface electromyography will be used to determine motor control in the upper trapezius muscle before and after treatment. The outcome measures in the group with neck pain will be a numerical pain rating scale (range: 0 (no pain) to 10 (maximum pain)), documentation of the pain area on a body chart and cervical range of motion. Comparisons before and after acupuncture treatment will demonstrate whether acupoints affect the activity of the upper trapezius muscle, pain and cervical range of motion. The purpose of this randomized clinical trial is to evaluate the immediate effect of acupuncture on pain, cervical range of motion and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain. Data will be published after the study is completed. The study will support the practice of evidence-based physical therapy for individuals with nonspecific neck pain. This trial was registered with Clinicaltrials.gov (identifier: NCT0984021 ) on 7 November 2013 ( https://clinicaltrials.gov/ct2/show/NCT01984021 ).

Comparison of methods for removing electromagnetic noise from electromyographic signals.

Science.gov (United States)

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

2012-02-01

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.

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)

Can neuromuscular fatigue threshold bedetermined by short and non-exhaustive bouts?. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p254

Directory of Open Access Journals (Sweden)

Alexandre Hideki Okano

2012-05-01

Full Text Available The present study determined the neuromuscular fatigue threshold (NFT using four different time-periods of analysis of the electromyographic signal and compared these estimations with critical power (CP. Fifteen healthy young men (73.6 ± 5.1 kg, 177.8 ± 7.0 cm, 23.4 ± 5.2 years performed 3-4 different severe constant workload trials until exhaustion on a cycle ergometer with simultaneous SEMG signals acquisition. The obtained data permitted NFT estimation with four different periods of analysis as follows: initial 30s (T30, 1min (T1, 2min (T2 and total time (TT, as well as CP. T30 and T1 were significantly higher than TT and CP and, T2 and TT did not differ between each other, and both were significantly higher than CP. In addition, TT was significantly correlated to CP (0.72; P < 0.05 and to T2 (0.58; P < 0.05. We conclude that NFT overestimates CP, independent of the time-period analysis used for its determination.

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, José M.

2014-01-01

Background Aging is a multifactorial process that leads to changes in the quantity and quality of skeletal muscle and contributes to decreased levels of muscle strength. Objective This study sought to investigate whether the isometric muscle strength, fat-free mass (FFM) and power of the electromyographic (EMG) signal of the upper and lower limbs of women are similarly affected by aging. Method The sample consisted of 63 women, who were subdivided into three groups (young (YO) n=33, 24.7±3.5 years; middle age (MA) n=15, 58.6±4.2 years; and older adults (OA). n=15, 72.0±4.2 years). Isometric strength was recorded simultaneously with the capture of the electrical activity of the flexor muscles of the fingers and the vastus lateralis during handgrip and knee extension tests, respectively. FFM was assessed using dual-energy X-ray absorptiometry. Results The handgrip strength measurements were similar among groups (p=0.523), whereas the FFM of the upper limbs was lower in group OA compared to group YO (p=0.108). The RMSn values of the hand flexors were similar among groups (p=0.754). However, the strength of the knee extensors, the FFM of the lower limbs and the RMSn values of the vastus lateralis were lower in groups MA (p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and pisometric muscle strength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb. PMID:24676705

Immediate effect of selective neuromuscular electrical stimulation on the electromyographic activity of the vastus medialis oblique muscle

Directory of Open Access Journals (Sweden)

Jamilson Simões Brasileiro

2008-04-01

Full Text Available The Patellofemoral pain syndrome (PFPS is described as an anterior or retropatellar knee pain in the absence of other associated diseases, and has often been associated with dysfunction of the vastus medialis oblique muscle (VMO. However, several studies have demonstrated the impossibility of selectively activating this muscle with exercises. The aim of the present study was to analyze the immediate effect of neuromuscular electrical stimulation of VMO muscle by means of monitoring the electromyographic activity of the vastus medialis oblique (VMO and vastus lateralis (VL muscles. Eighteen healthy women with a mean age of 23.2 years and mean BMI of 20 Kg/m2 were evaluated. The study protocol included electromyographic analysis of VMO and VL muscles, before and immediately after neuromuscular electrical stimulation of the VMO muscle. During the electromyographic analysis, the volunteers performed maximal voluntary isometric contraction in a 60° knee extension on an isokinetic dynamometer. “Russian current” apparatus was used for electrical stimulation. Results: The data analysis demonstrated a signifi cant increase in VMO activation intensity immediately after it had been electrically stimulated (p=0.0125, whereas VL activation intensity exhibited no signifi cant increase (p=0.924. Moreover, a significant increase in the VMO/VL ratio was also detected (p=0.048. In this study it was observed that electrical stimulation modifiedthe VMO/VL ratio, which suggests electrical stimulation has a benefi cial effect on VMO muscle strength. Resumo A Síndrome da dor patelofemoral (SDPF é descrita como dor anterior ou retro-patelar do joelho na ausência de outras patologias associadas, sendo freqüentemente associada à disfunção do Vasto Medial Oblíquo (VMO. Entretanto, diversos estudos têm demonstrado a impossibilidade de ativar seletivamente este músculo através de exercícios. O objetivo do presente estudo foi analisar o efeito imediato da

Relationship between electromyographic activity of the vastus lateralis while standing and the extent of bilateral simulated knee-flexion contractures.

Science.gov (United States)

Potter, P J; Kirby, R L

1991-12-01

The effect of simulated bilateral knee-flexion contractures (KFC) on the electromyographic (EMG) activity of the vastus lateralis was studied by testing 10 normal subjects using surface EMG to test the hypothesis that the activity of the knee extensors would increase as a function of the severity of the contracture. The root mean square of the EMG activity was determined from four 4-s samples taken at 30-s intervals, during 2 min of standing in each of five positions of simulated KFC (0 degree, 10 degrees, 20 degrees, 30 degrees and 40 degrees). A randomly balanced order of conditions was used. KFC were simulated in each subject by means of an adjustable line from the subject's waist to the sole of each foot. An analysis of variance was used to contrast EMG activity, and a significant difference was found between each of the positions (P less than 0.05). The mean (+/- 1 SD) EMG activity, expressed as a percentage of the maximum voluntary contraction, was 0.3% (+/- 0.2) at 0 degree, 7.6% (+/- 5.6) at 10 degrees, 10.9% (+/- 7.6) at 20 degrees, 16.6% (+/- 12.4) at 30 degrees and 24.0% (+/- 14.0) at 40 degrees. A linear relationship was found (r2 = 0.986), expressed by the equation y = 0.62 + 0.56 x, where y represents EMG activity and x represents the extent of simulated KFC (P = 0.0007). The results provide insight into the increased knee extensor activity necessary to stand with KFC and underline the importance of treating this common disorder.

Effects of 2 ankle destabilization devices on electromyography measures during functional exercises in individuals with chronic ankle instability.

Science.gov (United States)

Donovan, Luke; Hart, Joseph M; Hertel, Jay

2015-03-01

Randomized crossover laboratory study. To determine the effects of ankle destabilization devices on surface electromyography (sEMG) measures of selected lower extremity muscles during functional exercises in participants with chronic ankle instability. Ankle destabilization devices are rehabilitation tools that can be worn as a boot or sandal to increase lower extremity muscle activation during walking in healthy individuals. However, they have not been tested in a population with pathology. Fifteen adults with chronic ankle instability participated. Surface electromyography electrodes were located over the anterior tibialis, fibularis longus, lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius. The activity level of these muscles was recorded in a single testing session during unipedal stance with eyes closed, the Star Excursion Balance Test, lateral hops, and treadmill walking. Each task was performed under 3 conditions: shod, ankle destabilization boot, and ankle destabilization sandal. Surface electromyography signal amplitudes were measured for each muscle during each exercise for all 3 conditions. Participants demonstrated a significant increase, with moderate to large effect sizes, in sEMG signal amplitude of the fibularis longus in the ankle destabilization boot and ankle destabilization sandal conditions during the unipedal eyes-closed balance test, the Star Excursion Balance Test in the anterior and posteromedial directions, lateral hops, and walking, when compared to the shod condition. Both devices also resulted in an increase in sEMG signal amplitudes, with large effect sizes of the lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius during the unipedal-stance-with-eyes-closed test, compared to the shod condition. Wearing ankle destabilization devices caused greater muscle activation during functional exercises in individuals with chronic ankle instability. Based on the magnitude of the effect, there were

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%.

Assessment of Muscle Fatigue Associated with Prolonged Standing in the Workplace

Science.gov (United States)

Omar, Abdul Rahman; Saman, Alias Mohd; Othman, Ibrahim

2012-01-01

Objectives The objectives of this study were to determine the psychological fatigue and analyze muscle activity of production workers who are performing processes jobs while standing for prolonged time periods. Methods The psychological fatigue experienced by the workers was obtained through questionnaire surveys. Meanwhile, muscle activity has been analyzed using surface electromyography (sEMG) measurement. Lower extremities muscles include: erector spinae, tibialis anterior, and gastrocnemius were concurrently measured for more than five hours of standing. Twenty male production workers in a metal stamping company participated as subjects in this study. The subjects were required to undergo questionnaire surveys and sEMG measurement. Results Results of the questionnaire surveys found that all subjects experienced psychological fatigue due to prolonged standing jobs. Similarly, muscle fatigue has been identified through sEMG measurement. Based on the non-parametric statistical test using the Spearman's rank order correlation, the left erector spinae obtained a moderate positive correlation and statistically significant (rs = 0.552, p fatigue and to muscle fatigue among the production workers. PMID:22953228

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.

Effect of age on changes in motor units functional connectivity.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh

2015-08-01

With age, there is a change in functional connectivity of motor units in muscle. This leads to reduced muscle strength. This study has investigated the effect of age on the changes in the motor unit recruitment by measuring the mutual information between multiple channels of surface electromyogram (sEMG) of biceps brachii muscle. It is hypothesised that with ageing, there is a reduction in number of motor units, which can lead to an increase in the dependency of remaining motor units. This increase can be observed in the mutual information between the multiple channels of the muscle activity. Two channels of sEMG were recorded during the maximum level of isometric contraction. 28 healthy subjects (Young: age range 20-35years and Old: age range - 60-70years) participated in the experiments. The normalized mutual information (NMI), a measure of dependency factor, was computed for the sEMG recordings. Statistical analysis was performed to test the effect of age on NMI. The results show that the NMI among the older cohort was significantly higher when compared with the young adults.

Is the timed loaded standing test a valid measure of back muscle endurance in people with vertebral osteoporosis?

Science.gov (United States)

Newman, M; Newman, R; Hughes, T; Vadher, K; Barker, K L

2018-04-01

Timed loaded standing (TLS) is a suggested measure of back muscle endurance for people with vertebral osteoporosis. Surface electromyography revealed back muscles work harder and fatigue during TLS. The test end-point and total time were associated with back fatigue. The findings help demonstrate the concurrent validity of the TLS test. The TLS test is suggested as a measure of back muscle endurance for patients with vertebral osteoporosis. However, to date, no study has demonstrated that TLS does measure back extensor or erector spinae (ES) muscle endurance. We used surface electromyography (sEMG) to investigate the performance of the thoracic ES muscles during TLS. Thirty-six people with vertebral osteoporosis with a mean age of 71.6 (range 45-86) years participated. sEMG recordings were made of the ES at T3 and T12 bilaterally during quiet standing (QS) and TLS. The relative (%) change in sEMG amplitude between conditions was compared. Fatigue was evaluated by analysing the change in median frequency (MF) of the sEMG signal during TLS, and the correlation between maximal TLS time and rate of MF decline was examined. Activity in the ES increased significantly during TLS at all electrode locations. During TLS, the MF declined at a mean rate of -24.2% per minute (95% C.I. -26.5 to -21.9%). The MF slope and test time were strongly correlated (r 2  = 0.71), and at test end, the final MF dropped to an average 89% (95% C.I. 85 to 93%) of initial MF. Twenty-eight participants (78%) reported fatigue was the main reason for stopping, and for eight (22%), it was pain. This study demonstrates that TLS challenges the ES muscles in the thoracic region and results in ES fatigue. Endurance time and the point at which the TLS test ends are strongly related to ES fatigue.

Surface EMG electrodes do not accurately record from lumbar multifidus muscles.

Science.gov (United States)

Stokes, Ian A F; Henry, Sharon M; Single, Richard M

2003-01-01

This study investigated whether electromyographic signals recorded from the skin surface overlying the multifidus muscles could be used to quantify their activity. Comparison of electromyography signals recorded from electrodes on the back surface and from wire electrodes within four different slips of multifidus muscles of three human subjects performing isometric tasks that loaded the trunk from three different directions. It has been suggested that suitably placed surface electrodes can be used to record activity in the deep multifidus muscles. We tested whether there was a stronger correlation and more consistent regression relationship between signals from electrodes overlying multifidus and longissimus muscles respectively than between signals from within multifidus and from the skin surface electrodes over multifidus. The findings provided consistent evidence that the surface electrodes placed over multifidus muscles were more sensitive to the adjacent longissimus muscles than to the underlying multifidus muscles. The R(2) for surface versus intra-muscular comparisons was 0.64, while the average R(2) for surface-multifidus versus surface-longissimus comparisons was 0.80. Also, the magnitude of the regression coefficients was less variable between different tasks for the longissimus versus surface multifidus comparisons. Accurate measurement of multifidus muscle activity requires intra-muscular electrodes. Electromyography is the accepted technique to document the level of muscular activation, but its specificity to particular muscles depends on correct electrode placement. For multifidus, intra-muscular electrodes are required.

Reduced Electromyographic Fatigue Threshold after Performing a Cognitive Fatiguing Task.

Science.gov (United States)

Ferris, Justine R; Tomlinson, Mary A; Ward, Tayler N; Pepin, Marie E; Malek, Moh H

2018-02-22

Cognitive fatigue tasks performed prior to exercise may reduce exercise capacity. The electromyographic fatigue threshold (EMGFT) is the highest exercise intensity that can be maintained without significant increase in the EMG amplitude versus time relationship. To date, no studies have examined the effect of cognitive fatigue on the estimation of the EMGFT. The purpose of this study, therefore, was to determine whether or not cognitive fatigue prior to performing exercise reduces the estimated EMGFT. Eight healthy college-aged men were recruited from a university student population and visited the laboratory on multiple occasions. In a randomized order, subjects performed either the cognitive fatigue task (AX Continuous Performance Test; AX-CPT) for 60 min on one visit (experimental condition) or watched a video on trains for 60 min on the other visit (control condition). After each condition, subjects performed the incremental single-leg knee-extensor ergometry test while the EMG amplitude was recorded from the rectus femoris muscle and heart rate was monitored throughout. Thereafter, the EMGFT was calculated for each participant for each visit and compared using paired samples t-test. For exercise outcomes, there were no significant mean differences for maximal power output between the two conditions (control: 51 ± 5 vs. fatigue: 50 ± 3 W), but a significant decrease in EMGFT between the two conditions (control: 31 ± 3 vs. fatigue: 24 ± 2 W; p = 0.013). Moreover, maximal heart rate was significantly different between the two conditions (control: 151 ± 5 vs. fatigue: 132 ± 6; p = 0.027). These results suggest that performing the cognitive fatiguing task reduces the EMGFT with a corresponding reduction in maximal heart rate response.

Linear correlation between fractal dimension of surface EMG signal from Rectus Femoris and height of vertical jump

International Nuclear Information System (INIS)

Ancillao, Andrea; Galli, Manuela; Rigoldi, Chiara; Albertini, Giorgio

2014-01-01

Fractal dimension was demonstrated to be able to characterize the complexity of biological signals. The EMG time series are well known to have a complex behavior and some other studies already tried to characterize these signals by their fractal dimension. This paper is aimed at studying the correlation between the fractal dimension of surface EMG signal recorded over Rectus Femoris muscles during a vertical jump and the height reached in that jump. Healthy subjects performed vertical jumps at different heights. Surface EMG from Rectus Femoris was recorded and the height of each jump was measured by an optoelectronic motion capture system. Fractal dimension of sEMG was computed and the correlation between fractal dimension and eight of the jump was studied. Linear regression analysis showed a very high correlation coefficient between the fractal dimension and the height of the jump for all the subjects. The results of this study show that the fractal dimension is able to characterize the EMG signal and it can be related to the performance of the jump. Fractal dimension is therefore an useful tool for EMG interpretation

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

Directory of Open Access Journals (Sweden)

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.

Electromyographic activity associated with spontaneous functional recovery after spinal cord injury in rats.

Science.gov (United States)

Kaegi, Sibille; Schwab, Martin E; Dietz, Volker; Fouad, Karim

2002-07-01

This investigation was designed to study the spontaneous functional recovery of adult rats with incomplete spinal cord injury (SCI) at thoracic level during a time course of 2 weeks. Daily testing sessions included open field locomotor examination and electromyographic (EMG) recordings from a knee extensor (vastus lateralis, VL) and an ankle flexor muscle (tibialis anterior, TA) in the hindlimbs of treadmill walking rats. The BBB score (a locomotor score named after Basso et al., 1995, J. Neurotrauma, 12, 1-21) and various measures from EMG recordings were analysed (i.e. step cycle duration, rhythmicity of limb movements, flexor and extensor burst duration, EMG amplitude, root-mean-square, activity overlap between flexor and extensor muscles and hindlimb coupling). Directly after SCI, a marked drop in locomotor ability occurred in all rats with subsequent partial recovery over 14 days. The recovery was most pronounced during the first week. Significant changes were noted in the recovery of almost all analysed EMG measures. Within the 14 days of recovery, many of these measures approached control levels. Persistent abnormalities included a prolonged flexor burst and increased activity overlap between flexor and extensor muscles. Activity overlap between flexor and extensor muscles might be directly caused by altered descending input or by maladaptation of central pattern generating networks and/or sensory feedback.

Suprahyoid Muscle Complex: A Reliable Neural Assessment Tool For Dysphagia?

DEFF Research Database (Denmark)

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

be a non-invasive reliable neural assessment tool for patients with dysphagia. Objective: To investigate the possibility 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...

Robust Bio-Signal Based Control of an Intelligent Wheelchair

Directory of Open Access Journals (Sweden)

Dongyi Chen

2013-09-01

Full Text Available In this paper, an adaptive human-machine interaction (HMI method that is based on surface electromyography (sEMG signals is proposed for the hands-free control of an intelligent wheelchair. sEMG signals generated by the facial movements are obtained by a convenient dry electrodes sensing device. After the signals features are extracted from the autoregressive model, control data samples are updated and trained by an incremental online learning algorithm in real-time. Experimental results show that the proposed method can significantly improve the classification accuracy and training speed. Moreover, this method can effectively reduce the influence of muscle fatigue during a long time operation of sEMG-based HMI.

Pathological tremor prediction using surface EMG and acceleration: potential use in “ON-OFF” demand driven deep brain stimulator design

Science.gov (United States)

Basu, Ishita; Graupe, Daniel; Tuninetti, Daniela; Shukla, Pitamber; Slavin, Konstantin V.; Metman, Leo Verhagen; Corcos, Daniel M.

2013-01-01

Objective We present a proof of concept for a novel method of predicting the onset of pathological tremor using non-invasively measured surface electromyogram (sEMG) and acceleration from tremor-affected extremities of patients with Parkinson’s disease (PD) and Essential tremor (ET). Approach The tremor prediction algorithm uses a set of spectral (fourier and wavelet) and non-linear time series (entropy and recurrence rate) parameters extracted from the non-invasively recorded sEMG and acceleration signals. Main results The resulting algorithm is shown to successfully predict tremor onset for all 91 trials recorded in 4 PD patients and for all 91 trials recorded in 4 ET patients. The predictor achieves a 100% sensitivity for all trials considered, along with an overall accuracy of 85.7% for all ET trials and 80.2% for all PD trials. By using a Pearson’s chi-square test, the prediction results are shown to significantly differ from a random prediction outcome. Significance The tremor prediction algorithm can be potentially used for designing the next generation of non-invasive closed-loop predictive ON-OFF controllers for deep brain stimulation (DBS), used for suppressing pathological tremor in such patients. Such a system is based on alternating ON and OFF DBS periods, an incoming tremor being predicted during the time intervals when DBS is OFF, so as to turn DBS back ON. The prediction should be a few seconds before tremor re-appears so that the patient is tremor-free for the entire DBS ON-OFF cycle as well as the tremor-free DBS OFF interval should be maximized in order to minimize the current injected in the brain and battery usage. PMID:23658233

Pathological tremor prediction using surface electromyogram and acceleration: potential use in ‘ON-OFF’ demand driven deep brain stimulator design

Science.gov (United States)

Basu, Ishita; Graupe, Daniel; Tuninetti, Daniela; Shukla, Pitamber; Slavin, Konstantin V.; Verhagen Metman, Leo; Corcos, Daniel M.

2013-06-01

Objective. We present a proof of concept for a novel method of predicting the onset of pathological tremor using non-invasively measured surface electromyogram (sEMG) and acceleration from tremor-affected extremities of patients with Parkinson’s disease (PD) and essential tremor (ET). Approach. The tremor prediction algorithm uses a set of spectral (Fourier and wavelet) and nonlinear time series (entropy and recurrence rate) parameters extracted from the non-invasively recorded sEMG and acceleration signals. Main results. The resulting algorithm is shown to successfully predict tremor onset for all 91 trials recorded in 4 PD patients and for all 91 trials recorded in 4 ET patients. The predictor achieves a 100% sensitivity for all trials considered, along with an overall accuracy of 85.7% for all ET trials and 80.2% for all PD trials. By using a Pearson’s chi-square test, the prediction results are shown to significantly differ from a random prediction outcome. Significance. The tremor prediction algorithm can be potentially used for designing the next generation of non-invasive closed-loop predictive ON-OFF controllers for deep brain stimulation (DBS), used for suppressing pathological tremor in such patients. Such a system is based on alternating ON and OFF DBS periods, an incoming tremor being predicted during the time intervals when DBS is OFF, so as to turn DBS back ON. The prediction should be a few seconds before tremor re-appears so that the patient is tremor-free for the entire DBS ON-OFF cycle and the tremor-free DBS OFF interval should be maximized in order to minimize the current injected in the brain and battery usage.

Effects of massage therapy and occlusal splint therapy on electromyographic activity and the intensity of signs and symptoms in individuals with temporomandibular disorder and sleep bruxism: a randomized clinical trial.

Science.gov (United States)

Gomes, Cid André Fidelis de Paula; El Hage, Yasmin; Amaral, Ana Paula; Politti, Fabiano; Biasotto-Gonzalez, Daniela Aparecida

2014-01-01

Temporomandibular disorder (TDM) is the most common source of orofacial pain of a non-dental origin. Sleep bruxism is characterized by clenching and/or grinding the teeth during sleep and is involved in the perpetuation of TMD. The aim of the present study was to investigate the effects of massage therapy, conventional occlusal splint therapy and silicone occlusal splint therapy on electromyographic activity in the masseter and anterior temporal muscles and the intensity of signs and symptoms in individuals with severe TMD and sleep bruxism. Sixty individuals with severe TMD and sleep bruxism were randomly distributed into four treatment groups: 1) massage group, 2) conventional occlusal splint group, 3) massage + conventional occlusal splint group and 4) silicone occlusal splint group. Block randomization was employed and sealed opaque envelopes were used to conceal the allocation. Groups 2, 3 and 4 wore an occlusal splint for four weeks. Groups 1 and 3 received three weekly massage sessions for four weeks. All groups were evaluated before and after treatment through electromyographic analysis of the masseter and anterior temporal muscles and the Fonseca Patient History Index. The Wilcoxon test was used to compare the effects of the different treatments and repeated-measures ANOVA was used to determine the intensity of TMD. The inter-group analysis of variance revealed no statistically significant differences in median frequency among the groups prior to treatment. In the intra-group analysis, no statistically significant differences were found between pre-treatment and post-treatment evaluations in any of the groups. Group 3 demonstrated a greater improvement in the intensity of TMD in comparison to the other groups. Massage therapy and the use of an occlusal splint had no significant influence on electromyographic activity of the masseter or anterior temporal muscles. However, the combination of therapies led to a reduction in the intensity of signs and

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.

Comparison between Flail Arm Syndrome and Upper Limb Onset Amyotrophic Lateral Sclerosis: Clinical Features and Electromyographic Findings.

Science.gov (United States)

Yoon, Byung-Nam; Choi, Seong Hye; Rha, Joung-Ho; Kang, Sa-Yoon; Lee, Kwang-Woo; Sung, Jung-Joon

2014-09-01

Flail arm syndrome (FAS), an atypical presentation of amyotrophic lateral sclerosis (ALS), is characterized by progressive, predominantly proximal, weakness of upper limbs, without involvement of the lower limb, bulbar, or respiratory muscles. When encountering a patient who presents with this symptomatic profile, possible diagnoses include upper limb onset ALS (UL-ALS), and FAS. The lack of information regarding FAS may make differential diagnosis between FAS and UL-ALS difficult in clinical settings. The aim of this study was to compare clinical and electromyographic findings from patients diagnosed with FAS with those from patients diagnosed with UL-ALS. To accomplish this, 18 patients with FAS and 56 patients with UL-ALS were examined. Significant differences were observed between the 2 groups pertaining to the rate of fasciculation, patterns of predominantly affected muscles, and the Medical Research Council scale of the weakest muscle. The presence of upper motor neuron signs and lower motor neuron involvement evidenced through electromyography showed no significant between-group differences.

Comparison of quasi-static and dynamic squats: a three-dimensional kinematic, kinetic and electromyographic study of the lower limbs.

Science.gov (United States)

Clément, Julien; Hagemeister, Nicola; Aissaoui, Rachid; de Guise, Jacques A

2014-01-01

Numerous studies have described 3D kinematics, 3D kinetics and electromyography (EMG) of the lower limbs during quasi-static or dynamic squatting activities. One study compared these two squatting conditions but only at low speed on healthy subjects, and provided no information on kinetics and EMG of the lower limbs. The purpose of the present study was to contrast simultaneous recordings of 3D kinematics, 3D kinetics and EMG of the lower limbs during quasi-stat ic and fast-dynamic squats in healthy and pathological subjects. Ten subjects were recruited: five healthy and five osteoarthritis subjects. A motion-capture system, force plate, and surface electrodes respectively recorded 3D kinematics, 3D kinetics and EMG of the lower limbs. Each subject performed a quasi-static squat and several fast-dynamic squats from 0° to 70° of knee flexion. The two squatting conditions were compared for positions where quasi-static and fast-dynamic knee flexion-extension angles were similar. Mean differences between quasi-static and fast-dynamic squats were 1.5° for rotations, 1.9 mm for translations, 2.1% of subjects' body weight for ground reaction forces, 6.6 Nm for torques, 11.2 mm for center of pressure, and 6.3% of maximum fast-dynamic electromyographic activities for EMG. Some significant differences (psquats were small. 69.5% of compared data were equivalent. In conclusion, this study showed that quasi-static and fast-dynamic squatting activities are comparable in terms of 3D kinematics, 3D kinetics and EMG, although some reservations still remain. Copyright © 2014 Elsevier B.V. All rights reserved.

A Novel Feature Optimization for Wearable Human-Computer Interfaces Using Surface Electromyography Sensors

Directory of Open Access Journals (Sweden)

Han Sun

2018-03-01

Full Text Available The novel human-computer interface (HCI using bioelectrical signals as input is a valuable tool to improve the lives of people with disabilities. In this paper, surface electromyography (sEMG signals induced by four classes of wrist movements were acquired from four sites on the lower arm with our designed system. Forty-two features were extracted from the time, frequency and time-frequency domains. Optimal channels were determined from single-channel classification performance rank. The optimal-feature selection was according to a modified entropy criteria (EC and Fisher discrimination (FD criteria. The feature selection results were evaluated by four different classifiers, and compared with other conventional feature subsets. In online tests, the wearable system acquired real-time sEMG signals. The selected features and trained classifier model were used to control a telecar through four different paradigms in a designed environment with simple obstacles. Performance was evaluated based on travel time (TT and recognition rate (RR. The results of hardware evaluation verified the feasibility of our acquisition systems, and ensured signal quality. Single-channel analysis results indicated that the channel located on the extensor carpi ulnaris (ECU performed best with mean classification accuracy of 97.45% for all movement’s pairs. Channels placed on ECU and the extensor carpi radialis (ECR were selected according to the accuracy rank. Experimental results showed that the proposed FD method was better than other feature selection methods and single-type features. The combination of FD and random forest (RF performed best in offline analysis, with 96.77% multi-class RR. Online results illustrated that the state-machine paradigm with a 125 ms window had the highest maneuverability and was closest to real-life control. Subjects could accomplish online sessions by three sEMG-based paradigms, with average times of 46.02, 49.06 and 48.08 s

Electromyographic and biomechanical analysis of step negotiation in Charcot Marie Tooth subjects whose level walk is not impaired.

Science.gov (United States)

Lencioni, Tiziana; Piscosquito, Giuseppe; Rabuffetti, Marco; Sipio, Enrica Di; Diverio, Manuela; Moroni, Isabella; Padua, Luca; Pagliano, Emanuela; Schenone, Angelo; Pareyson, Davide; Ferrarin, Maurizio

2018-05-01

Charcot-Marie-Tooth (CMT) is a slowly progressive disease characterized by muscular weakness and wasting with a length-dependent pattern. Mildly affected CMT subjects showed slight alteration of walking compared to healthy subjects (HS). To investigate the biomechanics of step negotiation, a task that requires greater muscle strength and balance control compared to level walking, in CMT subjects without primary locomotor deficits (foot drop and push off deficit) during walking. We collected data (kinematic, kinetic, and surface electromyographic) during walking on level ground and step negotiation, from 98 CMT subjects with mild-to-moderate impairment. Twenty-one CMT subjects (CMT-NLW, normal-like-walkers) were selected for analysis, as they showed values of normalized ROM during swing and produced work at push-off at ankle joint comparable to those of 31 HS. Step negotiation tasks consisted in climbing and descending a two-step stair. Only the first step provided the ground reaction force data. To assess muscle activity, each EMG profile was integrated over 100% of task duration and the activation percentage was computed in four phases that constitute the step negotiation tasks. In both tasks, CMT-NLW showed distal muscle hypoactivation. In addition, during step-ascending CMT-NLW subjects had relevant lower activities of vastus medialis and rectus femoris than HS in weight-acceptance, and, on the opposite, a greater activation as compared to HS in forward-continuance. During step-descending, CMT-NLW showed a reduced activity of tibialis anterior during controlled-lowering phase. Step negotiation revealed adaptive motor strategies related to muscle weakness due to disease in CMT subjects without any clinically apparent locomotor deficit during level walking. In addition, this study provided results useful for tailored rehabilitation of CMT patients. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Comparación entre la respuesta de la actividad muscular lumbar en plataforma vibratoria y en ejercicio clásico de squat isométrico en 30º y 60º. (A comparison of the lumbar muscle activity responsein 30º and 60º isometric squat between whole-body vibration and a classic exercise.

Directory of Open Access Journals (Sweden)

Alejandro Santos-Lozano

2012-01-01

Full Text Available Whole-body vibration (WBV has improved as a variety of exercises, so it is necessary know muscles responses to the vibration stimulus.The aim of this work was to study and to compare the change in muscle activation in the lumbar area and lower body between the whole-body vibration exercise and classic strength exercises in isometric squat.23 subjects were exposed to six different loads in one of each exercise mode: vibration or classic strength. Both exercises were performed at 30º and 60º semi-squat position. Muscle activity of the lower body and lumbar area was measured using surface electromyography activity (EMG.The results showed that the response of lumbar area in WBV was lower than in the classic strength exercise at the same value of lower body sEMG. Lumbar sEMG was highest for the classic exercise. Moreover, during 30º squat sEMG was higher than during 60ºsquat.ResumenEl aumento del uso de la plataforma vibratoria como forma de realizar ejercicio conlleva la necesidad de conocer las respuestas musculares al estímulo de la misma.El objetivo de este trabajo ha sido estudiar y comparar la respuesta de la activación muscular de la zona lumbar y del tren inferior en el trabajo de plataforma vibratoria con el trabajo clásico de fuerza en un squat isométrico.23 sujetos fueron sometidos a 6 condiciones de vibración y a 6 de un trabajo clásico de pesas. Se analizó la sEMG del tren inferior y de la zona lumbar en un trabajo isométrico de un squat con flexión de 30º y 60º de rodilla.Los resultados muestran que para un mismo valor de sEMG del tren inferior, los valores de sEMG de la zona lumbar son menores en el ejercicio vibratorio. Existiendo en el trabajo de pesas una mayor exigencia en la zona lumbar. Además, con una flexión de 30º la activación muscular es mayor en todas las condiciones. (p

Fractal and twin SVM-based handgrip recognition for healthy subjects and trans-radial amputees using myoelectric signal.

Science.gov (United States)

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant; Jayadeva J

2016-02-01

Identifying functional handgrip patterns using surface electromygram (sEMG) signal recorded from amputee residual muscle is required for controlling the myoelectric prosthetic hand. In this study, we have computed the signal fractal dimension (FD) and maximum fractal length (MFL) during different grip patterns performed by healthy and transradial amputee subjects. The FD and MFL of the sEMG, referred to as the fractal features, were classified using twin support vector machines (TSVM) to recognize the handgrips. TSVM requires fewer support vectors, is suitable for data sets with unbalanced distributions, and can simultaneously be trained for improving both sensitivity and specificity. When compared with other methods, this technique resulted in improved grip recognition accuracy, sensitivity, and specificity, and this improvement was significant (κ=0.91).

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.

Detection of compensatory balance responses using wearable electromyography sensors for fall-risk assessment.

Science.gov (United States)

Nouredanesh, Mina; Kukreja, Sunil L; Tung, James

2016-08-01

Loss of balance is prevalent in older adults and populations with gait and balance impairments. The present paper aims to develop a method to automatically distinguish compensatory balance responses (CBRs) from normal gait, based on activity patterns of muscles involved in maintaining balance. In this study, subjects were perturbed by lateral pushes while walking and surface electromyography (sEMG) signals were recorded from four muscles in their right leg. To extract sEMG time domain features, several filtering characteristics and segmentation approaches are examined. The performance of three classification methods, i.e., k-nearest neighbor, support vector machines, and random forests, were investigated for accurate detection of CBRs. Our results show that features extracted in the 50-200Hz band, segmented using peak sEMG amplitudes, and a random forest classifier detected CBRs with an accuracy of 92.35%. Moreover, our results support the important role of biceps femoris and rectus femoris muscles in stabilization and consequently discerning CBRs. This study contributes towards the development of wearable sensor systems to accurately and reliably monitor gait and balance control behavior in at-home settings (unsupervised conditions), over long periods of time, towards personalized fall risk assessment tools.

Effect of clinical parameters on the control of myoelectric robotic prosthetic hands.

Science.gov (United States)

Atzori, Manfredo; Gijsberts, Arjan; Castellini, Claudio; Caputo, Barbara; Hager, Anne-Gabrielle Mittaz; Elsig, Simone; Giatsidis, Giorgio; Bassetto, Franco; Müller, Henning

2016-01-01

Improving the functionality of prosthetic hands with noninvasive techniques is still a challenge. Surface electromyography (sEMG) currently gives limited control capabilities; however, the application of machine learning to the analysis of sEMG signals is promising and has recently been applied in practice, but many questions still remain. In this study, we recorded the sEMG activity of the forearm of 11 male subjects with transradial amputation who were mentally performing 40 hand and wrist movements. The classification performance and the number of independent movements (defined as the subset of movements that could be distinguished with >90% accuracy) were studied in relationship to clinical parameters related to the amputation. The analysis showed that classification accuracy and the number of independent movements increased significantly with phantom limb sensation intensity, remaining forearm percentage, and temporal distance to the amputation. The classification results suggest the possibility of naturally controlling up to 11 movements of a robotic prosthetic hand with almost no training. Knowledge of the relationship between classification accuracy and clinical parameters adds new information regarding the nature of phantom limb pain as well as other clinical parameters, and it can lay the foundations for future "functional amputation" procedures in surgery.

Bioelectrical activity of the pelvic floor muscles after 6-week biofeedback training in nulliparous continent women.

Science.gov (United States)

Chmielewska, Daria; Stania, Magdalena; Smykla, Agnieszka; Kwaśna, Krystyna; Błaszczak, Edward; Sobota, Grzegorz; Skrzypulec-Plinta, Violetta

2016-01-01

The aim of the study was to evaluate the effects of a 6-week sEMG-biofeedback-assisted pelvic floor muscle training program on pelvic floor muscle activity in young continent women. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Biofeedback training was continued for 6 weeks, 3 times a week. Muscle strenghtening and endurance exercises were performed alternately. SEMG (surface electromyography) measurements were recorded on four different occasions: before training started, after the third week of training, after the sixth week of training, and one month after training ended. A 6-week sEMG-biofeedback-assisted pelvic floor muscle training program significantly decreased the resting activity of the pelvic floor muscles in supine lying and standing. The ability to relax the pelvic floor muscles after a sustained 60-second contraction improved significantly after the 6-week training in both positions. SEMG-biofeedback training program did not seem to affect the activity of the pelvic floor muscles or muscle fatigue during voluntary pelvic floor muscle contractions. SEMG-biofeedback-assisted pelvic floor muscle training might be recommended for physiotherapists to improve the effectiveness of their relaxation techniques.

Treatment of post-stroke dysphagia by vitalstim therapy coupled with conventional swallowing training.

Science.gov (United States)

Xia, Wenguang; Zheng, Chanjuan; Lei, Qingtao; Tang, Zhouping; Hua, Qiang; Zhang, Yangpu; Zhu, Suiqiang

2011-02-01

To investigate the effects of VitalStim therapy coupled with conventional swallowing training on recovery of post-stroke dysphagia, a total of 120 patients with post-stroke dysphagia were randomly and evenly divided into three groups: conventional swallowing therapy group, VitalStim therapy group, and VitalStim therapy plus conventional swallowing therapy group. Prior to and after the treatment, signals of surface electromyography (sEMG) of swallowing muscles were detected, swallowing function was evaluated by using the Standardized Swallowing Assessment (SSA) and Videofluoroscopic Swallowing Study (VFSS) tests, and swallowing-related quality of life (SWAL-QOL) was evaluated using the SWAL-QOL questionnaire. There were significant differences in sEMG value, SSA, VFSS, and SWAL-QOL scores in each group between prior to and after treatment. After 4-week treatment, sEMG value, SSA, VFSS and SWAL-QOL scores were significantly greater in the VitalStim therapy plus conventional swallowing training group than in the conventional swallowing training group and VitalStim therapy group, but no significant difference existed between conventional swallowing therapy group and VitalStim therapy group. It was concluded that VitalStim therapy coupled with conventional swallowing training was conducive to recovery of post-stroke dysphagia.

A novel spatiotemporal muscle activity imaging approach based on the Extended Kalman Filter.

Science.gov (United States)

Wang, Jing; Zhang, Yingchun; Zhu, Xiangjun; Zhou, Ping; Liu, Chenguang; Rymer, William Z

2012-01-01

A novel spatiotemporal muscle activity imaging (sMAI) approach has been developed using the Extended Kalman Filter (EKF) to reconstruct internal muscle activities from non-invasive multi-channel surface electromyogram (sEMG) recordings. A distributed bioelectric dipole source model is employed to describe the internal muscle activity space, and a linear relationship between the muscle activity space and the sEMG measurement space is then established. The EKF is employed to recursively solve the ill-posed inverse problem in the sMAI approach, in which the weighted minimum norm (WMN) method is utilized to calculate the initial state and a new nonlinear method is developed based on the propagating features of muscle activities to predict the recursive state. A series of computer simulations was conducted to test the performance of the proposed sMAI approach. Results show that the localization error rapidly decreases over 35% and the overlap ratio rapidly increases over 45% compared to the results achieved using the WMN method only. The present promising results demonstrate the feasibility of utilizing the proposed EKF-based sMAI approach to accurately reconstruct internal muscle activities from non-invasive sEMG recordings.

Can neuromuscular fatigue threshold bedetermined by short and non-exhaustive bouts?

Directory of Open Access Journals (Sweden)

Eduardo Bodnariuc Fontes

2012-04-01

Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p254 The present study determined the neuromuscular fatigue threshold (NFT using four different time-periods of analysis of the electromyographic signal and compared these estimations with critical power (CP. Fifteen healthy young men (73.6 ± 5.1 kg, 177.8 ± 7.0 cm, 23.4 ± 5.2 years performed 3-4 different severe constant workload trials until exhaustion on a cycle ergometer with simultaneous SEMG signals acquisition. The obtained data permitted NFT estimation with four different periods of analysis as follows: initial 30s (T30, 1min (T1, 2min (T2 and total time (TT, as well as CP. T30 and T1 were significantly higher than TT and CP and, T2 and TT did not differ between each other, and both were significantly higher than CP. In addition, TT was significantly correlated to CP (0.72; P < 0.05 and to T2 (0.58; P < 0.05. We conclude that NFT overestimates CP, independent of the time-period analysis used for its determination.

Evaluating the Ergonomic Benefit of a Wrist Brace on Wrist Posture, Muscle Activity, Rotational Stiffness, and Peak Shovel-Ground Impact Force During a Simulated Tree-Planting Task.

Science.gov (United States)

Sheahan, Peter J; Cashaback, Joshua G A; Fischer, Steven L

2017-09-01

Background Tree planters are at a high risk for wrist injury due to awkward postures and high wrist loads experienced during each planting cycle, specifically at shovel-ground impact. Wrist joint stiffness provides a measure that integrates postural and loading information. Objective The purpose of this study was to evaluate wrist joint stiffness requirements at the instant of shovel-ground impact during tree planting and determine if a wrist brace could alter muscular contributions to wrist joint stiffness. Method Planters simulated tree planting with and without wearing a brace on their planting arm. Surface electromyography (sEMG) from six forearm muscles and wrist kinematics were collected and used to calculate muscular contributions to joint rotational stiffness about the wrist. Results Wrist joint stiffness increased with brace use, an unanticipated and negative consequence of wearing a brace. As a potential benefit, planters achieved a more neutrally oriented wrist angle about the flexion/extension axis, although a less neutral wrist angle about the ulnar/radial axis was observed. Muscle activity did not change between conditions. Conclusion The joint stiffness analysis, combining kinematic and sEMG information in a biologically relevant manner, revealed clear limitations with the interface between the brace grip and shovel handle that jeopardized the prophylactic benefits of the current brace design. This limitation was not as evident when considering kinematics and sEMG data independently. Application A neuromechanical model (joint rotational stiffness) enhanced our ability to evaluate the brace design relative to kinematic and sEMG parameter-based metrics alone.

Avaliação eletromiográfica do músculo masseter em pessoas com paralisia facial periférica de longa duração Masseter muscle electromyographic assessment in subject with long lasting facial palsy

Directory of Open Access Journals (Sweden)

Adriana Rahal

2007-06-01

Full Text Available OBJETIVO: verificar a atividade elétrica do músculo masseter em pessoas com paralisia facial periférica de longa duração. MÉTODOS: participaram deste estudo seis sujeitos de ambos os sexos, com paralisia facial há pelo menos doze meses, sem queixas mastigatórias e sem disfunção temporomandibular e com pelo menos seis dentes em cada hemiarcada. Todos preencheram um questionário de anamnese e em seguida foram submetidos à eletromiografia de superfície dos masseteres de ambos os lados. As provas eletromiográficas foram: posição habitual com lábios fechados, apertamento dentário, mastigação habitual e unilateral à direita e à esquerda com uva passa. RESULTADOS: em todas as provas eletromiográficas não foram observadas diferenças significantes (p=0,05 entre os lados com e sem paralisia facial. CONCLUSÃO: observou-se com o presente estudo que a força do músculo masseter não sofre influência da paralisia facial de longa duração.PURPOSE: to check the masseter electrical activity in long lasting facial paralysis patients. METHODS: six subjects, with facial paralysis for over a period of twelve months, males and females, took part in this study. Patients should not show any masticatory complaints or have any diagnoses of temporo-mandibular joint dysfunction, having at least six teeth in each half dental ridge. All subjects filled out a questionnaire regarding oral habits and were assessed by surface electromyography of the masseter muscle of both sides. Electromyographic records were taken with lips closed at rest, teeth tightness, besides usual mastication, and unilateral mastication on both sides with raisins. RESULTS: in all electromyographic tests there were no statistically significant differences (p=0.05 between both sides, with and without facial paralysis. CONCLUSION: it was observed that the strength of the masseter muscle is not under the influence of long lasting facial paralysis.

Location of Instability During a Bench Press Alters Movement Patterns and Electromyographical Activity.

Science.gov (United States)

Nairn, Brian C; Sutherland, Chad A; Drake, Janessa D M

2015-11-01

Instability training devices with the bench press exercise are becoming increasingly popular. Typically, the instability device is placed at the trunk/upper body (e.g., lying on a Swiss ball); however, a recent product called the Attitube has been developed, which places the location of instability at the hands by users lifting a water-filled tube. Therefore, the purpose of this study was to analyze the effects of different instability devices (location of instability) on kinematic and electromyographical patterns during the bench press exercise. Ten healthy males were recruited and performed 1 set of 3 repetitions for 3 different bench press conditions: Olympic bar on a stable bench (BENCH), Olympic bar on a stability ball (BALL), and Attitube on a stable bench (TUBE). The eccentric and concentric phases were analyzed in 10% intervals while electromyography was recorded from 24 electrode sites, and motion capture was used to track elbow flexion angle and 3-dimensional movement trajectories and vertical velocity of the Bar/Attitube. The prime movers tended to show a reduction in muscle activity during the TUBE trials; however, pectoralis major initially showed increased activation during the eccentric phase of the TUBE condition. The trunk muscle activations were greatest during the TUBE and smallest during the BAR. In addition, the TUBE showed decreased range of elbow flexion and increased medial-lateral movement of the Attitube itself. The results further support the notion that instability devices may be more beneficial for trunk muscles rather than prime movers.

Evaluation of Myoelectric Activity of Paraspinal Muscles in Adolescents with Idiopathic Scoliosis during Habitual Standing and Sitting

Directory of Open Access Journals (Sweden)

Garcia Kwok

2015-01-01

Full Text Available There is a number of research work in the literature that have applied sEMG biofeedback as an instrument for muscle rehabilitation. Therefore, sEMG is a good tool for this research work and is used to record the myoelectric activity in the paraspinal muscles of those with AIS during habitual standing and sitting. After the sEMG evaluation, the root-mean-square (RMS sEMG values of the paraspinal muscles in the habitual postures reflect the spinal curvature situation of the PUMC Type Ia and IIc subjects. Both groups have a stronger average RMS sEMG value on the convex side of the affected muscle regions. Correction to posture as instructed by the physiotherapist has helped the subjects to achieve a more balanced RMS sEMG ratio in the trapezius and latissimus dorsi regions; the erector spinae in the thoracic region and/or erector spinae in the lumbar region. It is, therefore, considered that with regular practice of the suggested positions, those with AIS can use motor learning to achieve a more balanced posture. Consequently, the findings can be used in less intrusive early orthotic intervention and provision of care to those with AIS.

Evaluation of Myoelectric Activity of Paraspinal Muscles in Adolescents with Idiopathic Scoliosis during Habitual Standing and Sitting.

Science.gov (United States)

Kwok, Garcia; Yip, Joanne; Cheung, Mei-Chun; Yick, Kit-Lun

2015-01-01

There is a number of research work in the literature that have applied sEMG biofeedback as an instrument for muscle rehabilitation. Therefore, sEMG is a good tool for this research work and is used to record the myoelectric activity in the paraspinal muscles of those with AIS during habitual standing and sitting. After the sEMG evaluation, the root-mean-square (RMS) sEMG values of the paraspinal muscles in the habitual postures reflect the spinal curvature situation of the PUMC Type Ia and IIc subjects. Both groups have a stronger average RMS sEMG value on the convex side of the affected muscle regions. Correction to posture as instructed by the physiotherapist has helped the subjects to achieve a more balanced RMS sEMG ratio in the trapezius and latissimus dorsi regions; the erector spinae in the thoracic region and/or erector spinae in the lumbar region. It is, therefore, considered that with regular practice of the suggested positions, those with AIS can use motor learning to achieve a more balanced posture. Consequently, the findings can be used in less intrusive early orthotic intervention and provision of care to those with AIS.

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

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.

Electromyographic Patterns during Golf Swing: Activation Sequence Profiling and Prediction of Shot Effectiveness.

Science.gov (United States)

Verikas, Antanas; Vaiciukynas, Evaldas; Gelzinis, Adas; Parker, James; Olsson, M Charlotte

2016-04-23

This study analyzes muscle activity, recorded in an eight-channel electromyographic (EMG) signal stream, during the golf swing using a 7-iron club and exploits information extracted from EMG dynamics to predict the success of the resulting shot. Muscles of the arm and shoulder on both the left and right sides, namely flexor carpi radialis, extensor digitorum communis, rhomboideus and trapezius, are considered for 15 golf players (∼5 shots each). The method using Gaussian filtering is outlined for EMG onset time estimation in each channel and activation sequence profiling. Shots of each player revealed a persistent pattern of muscle activation. Profiles were plotted and insights with respect to player effectiveness were provided. Inspection of EMG dynamics revealed a pair of highest peaks in each channel as the hallmark of golf swing, and a custom application of peak detection for automatic extraction of swing segment was introduced. Various EMG features, encompassing 22 feature sets, were constructed. Feature sets were used individually and also in decision-level fusion for the prediction of shot effectiveness. The prediction of the target attribute, such as club head speed or ball carry distance, was investigated using random forest as the learner in detection and regression tasks. Detection evaluates the personal effectiveness of a shot with respect to the player-specific average, whereas regression estimates the value of target attribute, using EMG features as predictors. Fusion after decision optimization provided the best results: the equal error rate in detection was 24.3% for the speed and 31.7% for the distance; the mean absolute percentage error in regression was 3.2% for the speed and 6.4% for the distance. Proposed EMG feature sets were found to be useful, especially when used in combination. Rankings of feature sets indicated statistics for muscle activity in both the left and right body sides, correlation-based analysis of EMG dynamics and features

Electromyographic Patterns during Golf Swing: Activation Sequence Profiling and Prediction of Shot Effectiveness

Directory of Open Access Journals (Sweden)

Antanas Verikas

2016-04-01

Full Text Available This study analyzes muscle activity, recorded in an eight-channel electromyographic (EMG signal stream, during the golf swing using a 7-iron club and exploits information extracted from EMG dynamics to predict the success of the resulting shot. Muscles of the arm and shoulder on both the left and right sides, namely flexor carpi radialis, extensor digitorum communis, rhomboideus and trapezius, are considered for 15 golf players (∼5 shots each. The method using Gaussian filtering is outlined for EMG onset time estimation in each channel and activation sequence profiling. Shots of each player revealed a persistent pattern of muscle activation. Profiles were plotted and insights with respect to player effectiveness were provided. Inspection of EMG dynamics revealed a pair of highest peaks in each channel as the hallmark of golf swing, and a custom application of peak detection for automatic extraction of swing segment was introduced. Various EMG features, encompassing 22 feature sets, were constructed. Feature sets were used individually and also in decision-level fusion for the prediction of shot effectiveness. The prediction of the target attribute, such as club head speed or ball carry distance, was investigated using random forest as the learner in detection and regression tasks. Detection evaluates the personal effectiveness of a shot with respect to the player-specific average, whereas regression estimates the value of target attribute, using EMG features as predictors. Fusion after decision optimization provided the best results: the equal error rate in detection was 24.3% for the speed and 31.7% for the distance; the mean absolute percentage error in regression was 3.2% for the speed and 6.4% for the distance. Proposed EMG feature sets were found to be useful, especially when used in combination. Rankings of feature sets indicated statistics for muscle activity in both the left and right body sides, correlation-based analysis of EMG

Electromyographic Activity of the Cervical Flexor Muscles in Patients With Temporomandibular Disorders While Performing the Craniocervical Flexion Test: A Cross-Sectional Study

Science.gov (United States)

Silvestre, Rony; Fuentes, Jorge; da Costa, Bruno R.; Gadotti, Inae C.; Warren, Sharon; Major, Paul W.; Thie, Norman M.R.; Magee, David J.

2011-01-01

Background Most patients with temporomandibular disorders (TMD) have been shown to have cervical spine dysfunction. However, this cervical dysfunction has been evaluated only qualitatively through a general clinical examination of the cervical spine. Purpose The purpose of this study was to determine whether patients with TMD had increased activity of the superficial cervical muscles when performing the craniocervical flexion test (CCFT) compared with a control group of individuals who were healthy. Design A cross-sectional study was conducted. Methods One hundred fifty individuals participated in this study: 47 were healthy, 54 had myogenous TMD, and 49 had mixed TMD. All participants performed the CCFT. Data for electromyographic activity of the sternocleidomastoid (SCM) and anterior scalene (AS) muscles were collected during the CCFT for all participants. A 3-way mixed-design analysis of variance for repeated measures was used to evaluate the differences in EMG activity for selected muscles while performing the CCFT under 5 incremental levels. Effect size values were calculated to evaluate the clinical relevance of the results. Results Although there were no statistically significant differences in electromyographic activity in the SCM or AS muscles during the CCFT in patients with mixed and myogenous TMD compared with the control group, those with TMD tended to have increased activity of the superficial cervical muscles. Limitations The results obtained in this research are applicable for the group of individuals who participated in this study under the protocols used. They could potentially be applied to people with TMD having characteristics similar to those of the participants of this study. Conclusion This information may give clinicians insight into the importance of evaluation and possible treatment of the deep neck flexors in patients with TMD. However, future research should test the effectiveness of this type of program through a randomized controlled

Multi-channel electronics for secondary emission grid profile monitor of TTF linac

International Nuclear Information System (INIS)

Reingardt-Nikoulin, P.; Gaidash, V.; Mirzojan, A.; Kocharyan, V.; Noelle, D.

2004-01-01

According to the TTF beam experimental program, a measurement f the time dependence of the energy spread within the bunch train should be done by means of a standard device for profile measurements, that is Secondary Emission Grid (SEMG). SEMG on the high-energy TTF beam is placed in the focal plane of the magnet spectrometer. It should measure the total energy spread in the range from 0.1% up to a few percents for any single or any group of electron bunches in the bunch train of TTF Linac. SEMG profile measurements with new high sensitive electronics are described. Beam results of SEMG Monitor test are given for two modifications of an electronic preamplifier

Efecto del incremento de la PEEP en la actividad muscular respiratoria evaluado con electromiografía de superficie en individuos sanos bajo ventilación espontánea

Directory of Open Access Journals (Sweden)

Hernández-Valdivieso, Alher Mauricio

2016-07-01

Full Text Available Introduction: In a mechanically ventilated patient with increased airway resistance, the expiratory time span is insufficient to exhale all the inspired volume. In order to maintain oxygenation and to reduce the workload of respiratory muscles, it is common to apply an extrinsic positive end-expiratory pressure (PEEP that reduces tissue collapsibility, counterbalancing the increased resistance. Several studies have shown the usefulness of surface electromyography (sEMG to quantify the work of breathing (WOB, particularly in patients with obstructive diseases. Objective: To assess the effect of incremental PEEP in the respiratory muscle activity through sEMG in healthy volunteers noninvasively ventilated. Methods: Study of muscle activity in 10 healthy male volunteers, noninvasively ventilated for 20 minutes. The extrinsic PEEP was applied from 0 to 5 cm H2O in steps of 1 cm H2O at 30 seconds intervals. Results: The bio-potentials of diaphragm and sternocleidomastoid muscles revealed different breathing patterns in response to incremental PEEP: 1 increase in the workload of both muscles during inspiration and expiration; 2 increase in the workload of only one muscle; 3 a remarkable increase in muscle activity only in expiration. Conclusion: In noninvasively ventilated volunteers, sEMG quantitatively relates the PEEP level with changes in sternocleidomastoid and diaphragm activity.

The Comparison between Spectral and Entropic Measures Following Fatigue in Erector Spinae Muscles

Directory of Open Access Journals (Sweden)

Saeed Talebian

2016-03-01

Full Text Available Background: Surface electromyography (sEMG of muscles is a non-invasive tool that can be helpful in the assessment of muscle function and some motor control evaluations. A loss of force, known as muscle fatigue is accompanied by changes in muscle electrical activity. One of the most commonly used surface EMG parameters which reflects paraspinal muscle fatigue during different tasks and positions is median frequency. Although it is widely known that the electromyography power spectrum shifts to lower frequencies during fatiguing contraction, an opinion exists that the validity of spectral shifts in assessment of fatigue is questionable. Some researchers have examined whether other quantities derived from sEMG signals are better indicators for muscle fatigue. Following cyclic flexion/extension and consequence fatigue, variation in sEMG signals may be complex for study. The aim of this study was to determine which of the median frequency (MF or entropic (ENTR is more sensitive for measuring muscular fatigue in erector spinae muscles during cyclic flexion/extension. Methods: Surface electromyography of erector spine muscles was recorded in 25 healthy subjects during cyclic dynamic contractions. The experimental session consisted of two parts: measurement of Maximal Voluntary Contraction (MVC, and performing the fatigue test. All subjects performed rhythmic flexion/extension with 50% MVC loading against B-200 Isostation, about 4-6 minutes. The MF and ENTR of the muscle activities were computed to assess muscular fatigue. Results: Paired sample t-tests showed that MF and ENTR changes after fatigue test were significant (P<0.001. Percentage changes of both MF and ENTR were reduced, this reduction for ENTR was more than 40% (P<0.001. Conclusion: It seems that the changes of ENTR in muscle activities have the ability to measure muscular fatigue and is more sensitive in comparison to MF.

Comparison of sEMG-Based Feature Extraction and Motion Classification Methods for Upper-Limb Movement

Directory of Open Access Journals (Sweden)

Shuxiang Guo

2015-04-01

Full Text Available The surface electromyography (sEMG technique is proposed for muscle activation detection and intuitive control of prostheses or robot arms. Motion recognition is widely used to map sEMG signals to the target motions. One of the main factors preventing the implementation of this kind of method for real-time applications is the unsatisfactory motion recognition rate and time consumption. The purpose of this paper is to compare eight combinations of four feature extraction methods (Root Mean Square (RMS, Detrended Fluctuation Analysis (DFA, Weight Peaks (WP, and Muscular Model (MM and two classifiers (Neural Networks (NN and Support Vector Machine (SVM, for the task of mapping sEMG signals to eight upper-limb motions, to find out the relation between these methods and propose a proper combination to solve this issue. Seven subjects participated in the experiment and six muscles of the upper-limb were selected to record sEMG signals. The experimental results showed that NN classifier obtained the highest recognition accuracy rate (88.7% during the training process while SVM performed better in real-time experiments (85.9%. For time consumption, SVM took less time than NN during the training process but needed more time for real-time computation. Among the four feature extraction methods, WP had the highest recognition rate for the training process (97.7% while MM performed the best during real-time tests (94.3%. The combination of MM and NN is recommended for strict real-time applications while a combination of MM and SVM will be more suitable when time consumption is not a key requirement.

Preliminary investigation of an electromyography-controlled video game as a home program for persons in the chronic phase of stroke recovery.

Science.gov (United States)

Donoso Brown, Elena V; McCoy, Sarah Westcott; Fechko, Amber S; Price, Robert; Gilbertson, Torey; Moritz, Chet T

2014-08-01

To investigate the preliminary effectiveness of surface electromyography (sEMG) biofeedback delivered via interaction with a commercial computer game to improve motor control in chronic stroke survivors. Single-blinded, 1-group, repeated-measures design: A1, A2, B, A3 (A, assessment; B, intervention). Laboratory and participants' homes. A convenience sample of persons (N=9) between 40 and 75 years of age with moderate to severe upper extremity motor impairment and at least 6 months poststroke completed the study. The electromyography-controlled video game system targeted the wrist muscle activation with the goal of increasing selective muscle activation. Participants received several laboratory training sessions with the system and then were instructed to use the system at home for 45 minutes, 5 times per week for the following 4 weeks. Primary outcome measures included duration of system use, sEMG during home play, and pre/post sEMG measures during active wrist motion. Secondary outcomes included kinematic analysis of movement and functional outcomes, including the Wolf Motor Function Test and the Chedoke Arm and Hand Activity Inventory-9. One third of participants completed or exceeded the recommended amount of system use. Statistically significant changes were observed on both game play and pre/post sEMG outcomes. Limited carryover, however, was observed on kinematic or functional outcomes. This preliminary investigation indicates that use of the electromyography-controlled video game impacts muscle activation. Limited changes in kinematic and activity level outcomes, however, suggest that the intervention may benefit from the inclusion of a functional activity component. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Deep Learning with Convolutional Neural Networks Applied to Electromyography Data: A Resource for the Classification of Movements for Prosthetic Hands.

Science.gov (United States)

Atzori, Manfredo; Cognolato, Matteo; Müller, Henning

2016-01-01

Natural control methods based on surface electromyography (sEMG) and pattern recognition are promising for hand prosthetics. However, the control robustness offered by scientific research is still not sufficient for many real life applications, and commercial prostheses are capable of offering natural control for only a few movements. In recent years deep learning revolutionized several fields of machine learning, including computer vision and speech recognition. Our objective is to test its methods for natural control of robotic hands via sEMG using a large number of intact subjects and amputees. We tested convolutional networks for the classification of an average of 50 hand movements in 67 intact subjects and 11 transradial amputees. The simple architecture of the neural network allowed to make several tests in order to evaluate the effect of pre-processing, layer architecture, data augmentation and optimization. The classification results are compared with a set of classical classification methods applied on the same datasets. The classification accuracy obtained with convolutional neural networks using the proposed architecture is higher than the average results obtained with the classical classification methods, but lower than the results obtained with the best reference methods in our tests. The results show that convolutional neural networks with a very simple architecture can produce accurate results comparable to the average classical classification methods. They show that several factors (including pre-processing, the architecture of the net and the optimization parameters) can be fundamental for the analysis of sEMG data. Larger networks can achieve higher accuracy on computer vision and object recognition tasks. This fact suggests that it may be interesting to evaluate if larger networks can increase sEMG classification accuracy too.

Deep Learning with Convolutional Neural Networks Applied to Electromyography Data: A Resource for the Classification of Movements for Prosthetic Hands

Science.gov (United States)

Atzori, Manfredo; Cognolato, Matteo; Müller, Henning

2016-01-01

Natural control methods based on surface electromyography (sEMG) and pattern recognition are promising for hand prosthetics. However, the control robustness offered by scientific research is still not sufficient for many real life applications, and commercial prostheses are capable of offering natural control for only a few movements. In recent years deep learning revolutionized several fields of machine learning, including computer vision and speech recognition. Our objective is to test its methods for natural control of robotic hands via sEMG using a large number of intact subjects and amputees. We tested convolutional networks for the classification of an average of 50 hand movements in 67 intact subjects and 11 transradial amputees. The simple architecture of the neural network allowed to make several tests in order to evaluate the effect of pre-processing, layer architecture, data augmentation and optimization. The classification results are compared with a set of classical classification methods applied on the same datasets. The classification accuracy obtained with convolutional neural networks using the proposed architecture is higher than the average results obtained with the classical classification methods, but lower than the results obtained with the best reference methods in our tests. The results show that convolutional neural networks with a very simple architecture can produce accurate results comparable to the average classical classification methods. They show that several factors (including pre-processing, the architecture of the net and the optimization parameters) can be fundamental for the analysis of sEMG data. Larger networks can achieve higher accuracy on computer vision and object recognition tasks. This fact suggests that it may be interesting to evaluate if larger networks can increase sEMG classification accuracy too. PMID:27656140

How do tablet properties influence swallowing behaviours?

Science.gov (United States)

Yamamoto, Shinya; Taniguchi, Hiroshige; Hayashi, Hirokazu; Hori, Kazuhiro; Tsujimura, Takanori; Nakamura, Yuki; Sato, Hideaki; Inoue, Makoto

2014-01-01

Behavioural performance of tablet swallowing was evaluated with different tablet conditions in terms of size, number and surface coating. Four different types of tablets were prepared: small or large, and with or without a surface coating. Fourteen normal male adults were instructed to swallow the prepared tablets with 15 ml of water. The number of tablets in one trial was changed from one to three. To evaluate swallowing and tablet transport, electromyographic activity was recorded in the left suprahyoid muscles, and videofluorographic images were examined. All tablet conditions (size, number and surface coating) affected the swallowing performance in terms of total number of swallows, electromyographic burst patterns and location of remaining tablets. Increases in the size and number of tablets increased the number of swallows and electromyographic burst area and duration. In addition, all of these parameters increased while swallowing tablets without a coating compared with tablets with a coating. Location of the remaining tablets was mainly within the mouth. This study only clarified the normal pattern of tablet swallowing under several conditions in healthy subjects, but the results may facilitate comprehensive evaluation and treatment planning in terms of administering medication to dysphagic patients. © 2013 Royal Pharmaceutical Society.

An equilibrium-point model of electromyographic patterns during single-joint movements based on experimentally reconstructed control signals.

Science.gov (United States)

Latash, M L; Goodman, S R

1994-01-01

The purpose of this work has been to develop a model of electromyographic (EMG) patterns during single-joint movements based on a version of the equilibrium-point hypothesis, a method for experimental reconstruction of the joint compliant characteristics, the dual-strategy hypothesis, and a kinematic model of movement trajectory. EMG patterns are considered emergent properties of hypothetical control patterns that are equally affected by the control signals and peripheral feedback reflecting actual movement trajectory. A computer model generated the EMG patterns based on simulated movement kinematics and hypothetical control signals derived from the reconstructed joint compliant characteristics. The model predictions have been compared to published recordings of movement kinematics and EMG patterns in a variety of movement conditions, including movements over different distances, at different speeds, against different-known inertial loads, and in conditions of possible unexpected decrease in the inertial load. Changes in task parameters within the model led to simulated EMG patterns qualitatively similar to the experimentally recorded EMG patterns. The model's predictive power compares it favourably to the existing models of the EMG patterns. Copyright © 1994. Published by Elsevier Ltd.

Influence of an infant walker on onset and quality of walking pattern of locomotion:an electromyographic investigation.

Science.gov (United States)

Kauffman, I B; Ridenour, M

1977-12-01

Acquisition of bipedal locomotor skill in human infants was studied electromyographically with regard to the deprivation or enrichment behavior resulting from the frequent and regular use of an infant walker. Subjects were six sets of male, fraternal twins. One randomly selected sibling from each set underwent a training program, commencing at the age of 300 days, spending a total of 2 hr. per day in a walker. Siblings not included in this group were subjected to no special training. EMG recordings were taken of all subjects at specified intervals in order to establish a model of the typical motor pattern at various stages of skill development. These data were then contrasted with EMG data similarly obtained from the walker-trained subjects. Use of an infant walker modified the mechanics of the infant's locomotion in a number of important ways. It was shown that use of the walker enables an infant to commit substantial mechanical errors yet succeed in bipedal locomotion. Inasmuch as the mechanics of walker-assisted and non-assisted bipedal locomotion are dissimilar in so many important ways, positive transfer from walker-training appears questionable.

Muscle synergy analysis in children with cerebral palsy

Science.gov (United States)

Tang, Lu; Li, Fei; Cao, Shuai; Zhang, Xu; Wu, De; Chen, Xiang

2015-08-01

Objective. To explore the mechanism of lower extremity dysfunction of cerebral palsy (CP) children through muscle synergy analysis. Approach. Twelve CP children were involved in this study, ten adults (AD) and eight typically developed (TD) children were recruited as a control group. Surface electromyographic (sEMG) signals were collected bilaterally from eight lower limb muscles of the subjects during forward walking at a comfortable speed. A nonnegative matrix factorization algorithm was used to extract muscle synergies. In view of muscle synergy differences in number, structure and symmetry, a model named synergy comprehensive assessment (SCA) was proposed to quantify the abnormality of muscle synergies. Main results. There existed larger variations between the muscle synergies of the CP group and the AD group in contrast with the TD group. Fewer mature synergies were recruited in the CP group, and many abnormal synergies specific to the CP group appeared. Specifically, CP children were found to recruit muscle synergies with a larger difference in structure and symmetry between two legs of one subject and different subjects. The proposed SCA scale demonstrated its great potential to quantitatively assess the lower-limb motor dysfunction of CP children. SCA scores of the CP group (57.00 ± 16.78) were found to be significantly less (p < 0.01) than that of the control group (AD group: 95.74 ± 2.04; TD group: 84.19 ± 11.76). Significance. The innovative quantitative results of this study can help us to better understand muscle synergy abnormality in CP children, which is related to their motor dysfunction and even the physiological change in their nervous system.

Ground reaction forces, kinematics, and muscle activations during the windmill softball pitch.

Science.gov (United States)

Oliver, Gretchen D; Plummer, Hillary

2011-07-01

The aims of the present study were to examine quantitatively ground reaction forces, kinematics, and muscle activations during the windmill softball pitch, and to determine relationships between knee valgus and muscle activations, ball velocity and muscle activation as well as ball velocity and ground reaction forces. It was hypothesized that there would be an inverse relationship between degree of knee valgus and muscle activation, a direct relationship between ground reaction forces and ball velocity, and non-stride leg muscle activations and ball velocity. Ten female windmill softball pitchers (age 17.6 ± 3.47 years, stature 1.67 ± 0.07 m, weight 67.4 ± 12.2 kg) participated. Dependent variables were ball velocity, surface electromyographic (sEMG), kinematic, and kinetic data while the participant was the independent variable. Stride foot contact reported peak vertical forces of 179% body weight. There were positive relationships between ball velocity and ground reaction force (r = 0.758, n = 10, P = 0.029) as well as ball velocity and non-stride leg gluteus maximus (r = 0.851, n = 10, P = 0.007) and medius (r = 0.760, n = 10, P = 0.029) muscle activity, while there was no notable relationship between knee valgus and muscle activation. As the windmill softball pitcher increased ball velocity, her vertical ground reaction forces also increased. Proper conditioning of the lumbopelvic-hip complex, including the gluteals, is essential for injury prevention. From the data presented, it is evident that bilateral strength and conditioning of the gluteal muscle group is salient in the windmill softball pitch as an attempt to decrease incidence of injury.

Seizure Onset Detection based on a Uni- or Multi-modal Intelligent Seizure Acquisition (UISA/MISA) System

DEFF Research Database (Denmark)

Conradsen, Isa; Beniczky, Sándor; Wolf, Peter

2010-01-01

An automatic Uni- or Multi-modal Inteligent Seizure Acquisition (UISA/MISA) system is highly applicable for onset detection of epileptic seizures based on motion data. The modalities used are surface electromyography (sEMG), acceleration (ACC) and angular velocity (ANG). The new proposed automatic...... algorithm on motion data is extracting features as “log-sum” measures of discrete wavelet components. Classification into the two groups “seizure” versus “nonseizure” is made based on the support vector machine (SVM) algorithm. The algorithm performs with a sensitivity of 91-100%, a median latency of 1...... second and a specificity of 100% on multi-modal data from five healthy subjects simulating seizures. The uni-modal algorithm based on sEMG data from the subjects and patients performs satisfactorily in some cases. As expected, our results clearly show superiority of the multimodal approach, as compared...

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

Science.gov (United States)

PASTERNAK-JÚNIOR, Braulio; de SOUSA NETO, Manoel Damião; DIONÍSIO, Valdeci Carlos; PÉCORA, Jesus Djalma; SILVA, Ricardo Gariba

2012-01-01

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. PMID:22437679

Effectiveness of the Pilates method for individuals with nonspecific low back pain: clinical and electromyographic aspects.

Directory of Open Access Journals (Sweden)

Pâmela Maiara Machado

2018-02-01

Full Text Available Abstract AIMS The aim of this study was to verify the influence of Pilates on muscle activation of lumbar multifidus (LM and transversus abdominis/internal oblique muscles (TrA/IO in individuals with nonspecific low back pain. METHODS Twelve individuals of both sexes with non-specific low back pain were evaluated before and after a two-month Pilates program in relation to electromyographic activity of LM and TrA/IO, as well as clinical aspects such as pain, flexibility, muscular endurance, quality of life; and Fear-Avoidance Beliefs Questionnaire (in relation to physical and work-related activities. A statistical analysis was performed using a test for independent samples and significance was established at the level of 0.05. RESULTS After eight weeks of Pilates training, there was an improvement in the clinical parameters of pain, flexibility, muscular endurance and disability. The individuals presented lower LM activation (p=0.025, higher trunk extension strength (p=0.005 and an increase in time from onset to peak muscle activation (p=0.02. CONCLUSION Pilates protocol was effective for clinical improvement and motor behavior in patients with nonspecific low back pain and the parameters assessed showed a large effect size despite the small sample.

Electroencephalographic and electromyographic changes during the use of detomidine and detomidine-butorphanol combination in standing horses.

Science.gov (United States)

Kruluc, P; Nemec, Alenka

2006-03-01

Clinically, the use of detomidine and butorphanol is suitable for sedation and deepening of analgosedation. The aim of our study was to establish the influence of detomidine used alone and a butorphanol-detomidine combination on brain activity and to evaluate and compare brain responses (using electroencephalography, EEG) by recording SEF90 (spectral edge frequency 90%), individual brain wave fractions (beta, alpha, theta and delta) and electromyographic (EMG) changes in the left temporal muscle in standing horses. Ten clinically healthy cold-blooded horses were divided into two groups of five animals each. Group I received detomidine and Group II received detomidine followed by butorphanol 10 min later. SEF90, individual brain wave fractions and EMG were recorded with a pEEG (processed EEG) monitor using computerised processed electroencephalography and electromyography. The present study found that detomidine alone and the detomidine-butorphanol combination significantly reduced SEF90 and EMG, and they caused changes in individual brain wave fractions during sedation and particularly during analgosedation. The EMG results showed that the detomidine-butorphanol combination provided greater and longer muscle relaxation. Our EEG and EMG results confirmed that the detomidine-butorphanol combination is safer and more appropriate for painless and non-painless procedures on standing horses compared to detomidine alone.

Effects of Different Footwear Properties and Surface Instability on Neuromuscular Activity and Kinematics During Jumping.

Science.gov (United States)

Lesinski, Melanie; Prieske, Olaf; Borde, Ron; Beurskens, Rainer; Granacher, Urs

2018-04-13

Lesinski, M, Prieske, O, Borde, R, Beurskens, R, and Granacher, U. Effects of different footwear properties and surface instability on neuromuscular activity and kinematics during jumping. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to examine sex-specific effects of different footwear properties vs. barefoot condition during the performance of drop jumps (DJs) on stable and unstable surfaces on measures of jump performance, electromyographic (EMG) activity, and knee joint kinematics. Drop jump performance, EMG activity of lower-extremity muscles, as well as sagittal and frontal knee joint kinematics were tested in 28 healthy male (n = 14) and female (n = 14) physically active sports science students (23 ± 2 years) during the performance of DJs on stable and unstable surfaces using different footwear properties (elastic vs. minimal shoes) vs. barefoot condition. Analysis revealed a significantly lower jump height and performance index (Δ7-12%; p footwear conditions (Δ29%; p footwear-surface interactions were detected. Our findings revealed that surface instability had an impact on DJ performance, thigh/shank muscle activity, and knee joint kinematics. In addition, the single factors "footwear" and "sex" modulated knee joint kinematics during DJs. However, hardly any significant interaction effects were found. Thus, additional footwear-related effects can be neglected when performing DJs during training on different surfaces.

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

Influence of bench angle on upper extremity muscular activation during bench press exercise.

Science.gov (United States)

Lauver, Jakob D; Cayot, Trent E; Scheuermann, Barry W

2016-01-01

This study compared the muscular activation of the pectoralis major, anterior deltoid and triceps brachii during a free-weight barbell bench press performed at 0°, 30°, 45° and -15° bench angles. Fourteen healthy resistance trained males (age 21.4 ± 0.4 years) participated in this study. One set of six repetitions for each bench press conditions at 65% one repetition maximum were performed. Surface electromyography (sEMG) was utilised to examine the muscular activation of the selected muscles during the eccentric and concentric phases. In addition, each phase was subdivided into 25% contraction durations, resulting in four separate time points for comparison between bench conditions. The sEMG of upper pectoralis displayed no difference during any of the bench conditions when examining the complete concentric contraction, however differences during 26-50% contraction duration were found for both the 30° [122.5 ± 10.1% maximal voluntary isometric contraction (MVIC)] and 45° (124 ± 9.1% MVIC) bench condition, resulting in greater sEMG compared to horizontal (98.2 ± 5.4% MVIC) and -15 (96.1 ± 5.5% MVIC). The sEMG of lower pectoralis was greater during -15° (100.4 ± 5.7% MVIC), 30° (86.6 ± 4.8% MVIC) and horizontal (100.1 ± 5.2% MVIC) bench conditions compared to the 45° (71.9 ± 4.5% MVIC) for the whole concentric contraction. The results of this study support the use of a horizontal bench to achieve muscular activation of both the upper and lower heads of the pectoralis. However, a bench incline angle of 30° or 45° resulted in greater muscular activation during certain time points, suggesting that it is important to consider how muscular activation is affected at various time points when selecting bench press exercises.

Effects of experimental insoles on body posture, mandibular kinematics and masticatory muscles activity. A pilot study in healthy volunteers.

Science.gov (United States)

Marini, Ida; Alessandri Bonetti, Giulio; Bortolotti, Francesco; Bartolucci, Maria Lavinia; Gatto, Maria Rosaria; Michelotti, Ambra

2015-06-01

It has been hypothesized that different plantar sensory inputs could influence the whole body posture and dental occlusion but there is a lack of evidence on this possible association. To investigate the effects of experimental insoles redistributing plantar pressure on body posture, mandibular kinematics and electromyographic (EMG) activity of masticatory muscles on healthy subjects. A pilot study was conducted on 19 healthy volunteers that wore custom-made insoles normalizing the plantar pressure distribution for 2 weeks. Body posture parameters were measured by means of an optoelectronic stereophotogrammetric analysis; mandibular kinematics was analyzed by means of gothic arch tracings; superficial EMG activity of head and neck muscles was performed. Measurements were carried out 10 days before the insertion of the insoles, immediately before the insertion, the day after, 7 and 14 days after, in four different exteroceptive conditions. The outcomes of the present study show that insoles do not modify significantly over time the parameters of body posture, SEMG activity of head and neck muscles and mandibular kinematics. In this pilot study the experimental insoles did not significantly influence the body posture, the mandibular kinematics and the activity of masticatory muscles during a 14-day follow up period. Copyright © 2015 Elsevier Ltd. All rights reserved.

Flexion-relaxation ratio in computer workers with and without chronic neck pain.

Science.gov (United States)

Pinheiro, Carina Ferreira; dos Santos, Marina Foresti; Chaves, Thais Cristina

2016-02-01

This study evaluated the flexion-relaxation phenomenon (FRP) and flexion-relaxation ratios (FR-ratios) using surface electromyography (sEMG) of the cervical extensor muscles of computer workers with and without chronic neck pain, as well as of healthy subjects who were not computer users. This study comprised 60 subjects 20-45years of age, of which 20 were computer workers with chronic neck pain (CPG), 20 were computer workers without neck pain (NPG), and 20 were control individuals who do not use computers for work and use them less than 4h/day for other purposes (CG). FRP and FR-ratios were analyzed using sEMG of the cervical extensors. Analysis of FR-ratios showed smaller values in the semispinalis capitis muscles of the two groups of workers compared to the control group. The reference FR-ratio (flexion relaxation ratio [FRR], defined as the maximum activity in 1s of the re-extension/full flexion sEMG activity) was significantly higher in the computer workers with neck pain compared to the CG (CPG: 3.10, 95% confidence interval [CI95%] 2.50-3.70; NPG: 2.33, CI95% 1.93-2.74; CG: 1.99, CI95% 1.81-2.17; pneck pain, and such results suggested that each FR-ratio could have a different application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Discrete vs. Continuous Mapping of Facial Electromyography for Human-Machine-Interface Control: Performance and Training Effects

Science.gov (United States)

Cler, Meredith J.; Stepp, Cara E.

2015-01-01

Individuals with high spinal cord injuries are unable to operate a keyboard and mouse with their hands. In this experiment, we compared two systems using surface electromyography (sEMG) recorded from facial muscles to control an onscreen keyboard to type five-letter words. Both systems used five sEMG sensors to capture muscle activity during five distinct facial gestures that were mapped to five cursor commands: move left, move right, move up, move down, and “click”. One system used a discrete movement and feedback algorithm in which the user produced one quick facial gesture, causing a corresponding discrete movement to an adjacent letter. The other system was continuously updated and allowed the user to control the cursor’s velocity by relative activation between different sEMG channels. Participants were trained on one system for four sessions on consecutive days, followed by one crossover session on the untrained system. Information transfer rates (ITRs) were high for both systems compared to other potential input modalities, both initially and with training (Session 1: 62.1 bits/min, Session 4: 105.1 bits/min). Users of the continuous system showed significantly higher ITRs than the discrete users. Future development will focus on improvements to both systems, which may offer differential advantages for users with various motor impairments. PMID:25616053

A preliminary evaluation of myoelectrical energy distribution of the front neck muscles in pharyngeal phase during normal swallowing.

Science.gov (United States)

Mingxing Zhu; Wanzhang Yang; Samuel, Oluwarotimi Williams; Yun Xiang; Jianping Huang; Haiqing Zou; Guanglin Li

2016-08-01

Pharyngeal phase is a central hub of swallowing in which food bolus pass through from the oral cavity to the esophageal. Proper understanding of the muscular activities in the pharyngeal phase is useful for assessing swallowing function and the occurrence of dysphagia in humans. In this study, high-density (HD) surface electromyography (sEMG) was used to study the muscular activities in the pharyngeal phase during swallowing tasks involving three healthy male subjects. The root mean square (RMS) of the HD sEMG data was computed by using a series of segmented windows as myoelectrical energy. And the RMS of each window covering all channels (16×5) formed a matrix. During the pharyngeal phase of swallowing, three of the matrixes were chosen and normalized to obtain the HD energy maps and the statistical parameter. The maps across different viscosity levels offered the energy distribution which showed the muscular activities of the left and right sides of the front neck muscles. In addition, the normalized average RMS (NARE) across different viscosity levels revealed a left-right significant correlation (r=0.868±0.629, pstronger correlation when swallowing water. This pilot study suggests that HD sEMG would be a potential tool to evaluate muscular activities in pharyngeal phase during normal swallowing. Also, it might provide useful information for dysphagia diagnosis.

Evaluation of vibrant muscles over the shoulder region among workers of the hand screen printing industry.

Science.gov (United States)

Subramaniam, Shankar; Raju, Naveenkumar; Jeganathan, Karthick; Periyasamy, Mohankumar

2018-06-01

This study focuses on evaluation of the muscle activities associated with shoulder pain among workers of the hand screen printing (HSP) industry. Activities of three major muscles which showed higher muscle activity for a HSP job were observed for fatigue using surface electromyography (SEMG). The anatomical sites were chosen on the basis of a statistical survey and a visual inspection conducted before the experiment. Activities of the deltoid, teres major and infraspinatus were recorded using SEMG and the nature of muscle activities was studied for about 50 m of cloth printing. Data collected were processed using LabVIEW 2014 and the activities were analyzed using statistical tests and regression analyses. The results showed an increased risk of shoulder disorders with an increase in working time. Some of the risks which might cause disorders were predicted from the results; inspection and possible mitigations were suggested.

The influence of electromyographic recording methods and the innervation zone on the mean power frequency-torque relationships.

Science.gov (United States)

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

2015-06-01

This study examined the effects of electromyographic (EMG) recording methods and innervation zone (IZ) on the mean power frequency (MPF)-torque relationships. Nine subjects performed isometric ramp muscle actions of the leg extensors from 5% to 100% of maximal voluntary contraction with an eight channel linear electrode array over the IZ of the vastus lateralis. The slopes were calculated from the log-transformed monopolar and bipolar EMG MPF-torque relationships for each channel and subject and 95% confidence intervals (CI) were constructed around the slopes for each relationship and the composite of the slopes. Twenty-two to 55% of the subjects exhibited 95% CIs that did not include a slope of zero for the monopolar EMG MPF-torque relationships while 25-75% of the subjects exhibited 95% CIs that did not include a slope of zero for the bipolar EMG MPF-torque relationships. The composite of the slopes from the EMG MPF-torque relationships were not significantly different from zero for any method or channel, however, the method and IZ location slightly influenced the number of significant slopes on a subject-by-subject basis. The log-transform model indicated that EMG MPF-torque patterns were nonlinear regardless of recording method or distance from the IZ. Copyright © 2015 Elsevier Ltd. All rights reserved.

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)

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

Directory of Open Access Journals (Sweden)

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.

An electromyographic and kinematic comparison between an extendable conveyor system and an articulating belt conveyor used for truck loading and unloading tasks.

Science.gov (United States)

Lavender, Steven A; Nagavarapu, Shasank; Allread, W Gary

2017-01-01

Many retail distribution centers (DCs) manually load and unload boxes into or out of trailers and shipping containers. This study investigated whether an articulating belt conveyor with a height adjustable platform, positioned at the end of an extendable conveyor, significantly reduces shoulder and back muscle loading and the spine kinematics associated with these tasks. Electromyographic and kinematic data were collected from eight volunteer employees as trailers at a shoe DC were unloaded and from nine volunteer employees as trailers at an apparel DC were loaded. Participants in this repeated measures study handled boxes with a conventional powered extendable conveyor system and with the articulating belt conveyor positioned at the end of the extendable conveyor. Bilaterally the normalized activation levels of the erector spinae and anterior deltoid muscles were reduced when loading and unloading boxes with the articulating belt conveyor. Spine movement speeds were also reduced with the articulating conveyor. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Analysis of the Muscle Fatigue Based on Band Spectrum Entropy of Multi-channel Surface Electromyography].

Science.gov (United States)

Liu, Jian; Zou, Renling; Zhang, Dongheng; Xu, Xiulin; Hu, Xiufang

2016-06-01

Exercise-induced muscle fatigue is a phenomenon that the maximum voluntary contraction force or power output of muscle is temporarily reduced due to muscular movement.If the fatigue is not treated properly,it will bring about a severe injury to the human body.With multi-channel collection of lower limb surface electromyography signals,this article analyzes the muscle fatigue by adoption of band spectrum entropy method which combined electromyographic signal spectral analysis and nonlinear dynamics.The experimental result indicated that with the increase of muscle fatigue,muscle signal spectrum began to move to low frequency,the energy concentrated,the system complexity came down,and the band spectrum entropy which reflected the complexity was also reduced.By monitoring the entropy,we can measure the degree of muscle fatigue,and provide an indicator to judge fatigue degree for the sports training and clinical rehabilitation training.

Towards NIRS-based hand movement recognition.

Science.gov (United States)

Paleari, Marco; Luciani, Riccardo; Ariano, Paolo

2017-07-01

This work reports on preliminary results about on hand movement recognition with Near InfraRed Spectroscopy (NIRS) and surface ElectroMyoGraphy (sEMG). Either basing on physical contact (touchscreens, data-gloves, etc.), vision techniques (Microsoft Kinect, Sony PlayStation Move, etc.), or other modalities, hand movement recognition is a pervasive function in today environment and it is at the base of many gaming, social, and medical applications. Albeit, in recent years, the use of muscle information extracted by sEMG has spread out from the medical applications to contaminate the consumer world, this technique still falls short when dealing with movements of the hand. We tested NIRS as a technique to get another point of view on the muscle phenomena and proved that, within a specific movements selection, NIRS can be used to recognize movements and return information regarding muscles at different depths. Furthermore, we propose here three different multimodal movement recognition approaches and compare their performances.

A Component-Based Vocabulary-Extensible Sign Language Gesture Recognition Framework

Directory of Open Access Journals (Sweden)

Shengjing Wei

2016-04-01

Full Text Available Sign language recognition (SLR can provide a helpful tool for the communication between the deaf and the external world. This paper proposed a component-based vocabulary extensible SLR framework using data from surface electromyographic (sEMG sensors, accelerometers (ACC, and gyroscopes (GYRO. In this framework, a sign word was considered to be a combination of five common sign components, including hand shape, axis, orientation, rotation, and trajectory, and sign classification was implemented based on the recognition of five components. Especially, the proposed SLR framework consisted of two major parts. The first part was to obtain the component-based form of sign gestures and establish the code table of target sign gesture set using data from a reference subject. In the second part, which was designed for new users, component classifiers were trained using a training set suggested by the reference subject and the classification of unknown gestures was performed with a code matching method. Five subjects participated in this study and recognition experiments under different size of training sets were implemented on a target gesture set consisting of 110 frequently-used Chinese Sign Language (CSL sign words. The experimental results demonstrated that the proposed framework can realize large-scale gesture set recognition with a small-scale training set. With the smallest training sets (containing about one-third gestures of the target gesture set suggested by two reference subjects, (82.6 ± 13.2% and (79.7 ± 13.4% average recognition accuracy were obtained for 110 words respectively, and the average recognition accuracy climbed up to (88 ± 13.7% and (86.3 ± 13.7% when the training set included 50~60 gestures (about half of the target gesture set. The proposed framework can significantly reduce the user’s training burden in large-scale gesture recognition, which will facilitate the implementation of a practical SLR system.

A Component-Based Vocabulary-Extensible Sign Language Gesture Recognition Framework.

Science.gov (United States)

Wei, Shengjing; Chen, Xiang; Yang, Xidong; Cao, Shuai; Zhang, Xu

2016-04-19

Sign language recognition (SLR) can provide a helpful tool for the communication between the deaf and the external world. This paper proposed a component-based vocabulary extensible SLR framework using data from surface electromyographic (sEMG) sensors, accelerometers (ACC), and gyroscopes (GYRO). In this framework, a sign word was considered to be a combination of five common sign components, including hand shape, axis, orientation, rotation, and trajectory, and sign classification was implemented based on the recognition of five components. Especially, the proposed SLR framework consisted of two major parts. The first part was to obtain the component-based form of sign gestures and establish the code table of target sign gesture set using data from a reference subject. In the second part, which was designed for new users, component classifiers were trained using a training set suggested by the reference subject and the classification of unknown gestures was performed with a code matching method. Five subjects participated in this study and recognition experiments under different size of training sets were implemented on a target gesture set consisting of 110 frequently-used Chinese Sign Language (CSL) sign words. The experimental results demonstrated that the proposed framework can realize large-scale gesture set recognition with a small-scale training set. With the smallest training sets (containing about one-third gestures of the target gesture set) suggested by two reference subjects, (82.6 ± 13.2)% and (79.7 ± 13.4)% average recognition accuracy were obtained for 110 words respectively, and the average recognition accuracy climbed up to (88 ± 13.7)% and (86.3 ± 13.7)% when the training set included 50~60 gestures (about half of the target gesture set). The proposed framework can significantly reduce the user's training burden in large-scale gesture recognition, which will facilitate the implementation of a practical SLR system.

COMPARISON OF TWO VARIANTS OF A KATA TECHNIQUE (UNSU: THE NEUROMECHANICAL POINT OF VIEW

Directory of Open Access Journals (Sweden)

Francesco Felici

2009-11-01

Full Text Available The objective of this work was to characterize from a neuromechanical point of view a jump performed within the sequence of Kata Unsu in International top level karateka. A modified jumping technique was proposed to improve the already acquired technique. The neuromechanical evaluation, paralleled by a refereeing judgment, was then used to compare modified and classic technique to test if the modification could lead to a better performance capacity, e.g. a higher score during an official competition. To this purpose, four high ranked karateka were recruited and instructed to perform the two jumps. Surface electromyographic signals were recorded in a bipolar mode from the vastus lateralis, rectus femoris, biceps femoris, gluteus maximus, and gastrocnemious muscles of both lower limbs. Mechanical data were collected by means of a stereophotogrammetric system and force platforms. Performance was associated to parameters characterizing the initial conditions of the aerial phase and to the CoM maximal height. The most critical elements having a negative influence on the arbitral evaluation were associated to quantitative error indicators. 3D reconstruction of the movement and videos were used to obtain the referee scores. The Unsu jump was divided into five phases (preparation, take off, ascending flight, descending flight, and landing and the critical elements were highlighted. When comparing the techniques, no difference was found in the pattern of sEMG activation of the throwing leg muscles, while the push leg showed an earlier activation of RF and GA muscles at the beginning of the modified technique. The only significant improvement associated with the modified technique was evidenced at the beginning of the aerial phase, while there was no significant improvement of the referee score. Nevertheless, the proposed neuromechanical analysis, finalized to correlate technique features with the core performance indicators, is new in the field and is a

Multiple Impulse Therapy in the Assessment of Paraspinal Muscle Tone in Patients with Low Back Pain.

Science.gov (United States)

Haładaj, Robert; Topol, Mirosław

2016-11-30

Back pain is quite common in contemporary society, whose expectations of an effective analgesic therapy in conservative treatment lead to a necessity of searching for new diagnostic and therapeutic methods in physiotherapy. Out of the numerous physical therapy methods, Multiple Impulse Therapy (MIT) deserves special consideration. This paper aims to present and analyse the outcomes of MIT concerning paraspinal muscle tone and pain intensity in patients with low back pain. The study enrolled 117 patients (50 women and 67 men; average age of 45.3 yrs) with lumbar conditions confirmed by imaging studies. The participants received five MIT sessions within 14 days. Moreover, both before and after the therapy all the patients underwent bilateral assessment of the paraspinal muscle tone by surface electromyography (sEMG) with the NoraxonMyoTrace 400 system and an interactive head of the PulStarFRAS device. A VAS was used for evaluation of pain severity. The analysis of significance of differences between scores before and after treatment showed that all the parameters changed significantly (MIT: 11.11 Ibf before and 8.89 Ibf after the therapy; VAS: 6.04 before and 3.38 afterwards; sEMG: 9.29uV before and 7.51uV afterwards). 1. Multiple Impulse Therapy (MIT) is an effective and non-invasive method of back pain treatment. 2. MIT significantly reduces paraspinal muscle tone, as confirmed by sEMG results, and shows a strong analgesic effect.

Diagnostic accuracy of the electromyography parameters associated with anterior knee pain in the diagnosis of patellofemoral pain syndrome.

Science.gov (United States)

Ferrari, Deisi; Kuriki, Heloyse Uliam; Silva, Cristiano Rocha; Alves, Neri; Mícolis de Azevedo, Fábio

2014-08-01

To assess the diagnostic accuracy of the surface electromyography (sEMG) parameters associated with referred anterior knee pain in diagnosing patellofemoral pain syndrome (PFPS). Sensitivity and specificity analysis. Physical rehabilitation center and laboratory of biomechanics and motor control. Pain-free subjects (n=29) and participants with PFPS (n=22) selected by convenience. Not applicable. The diagnostic accuracy was calculated for sEMG parameters' reliability, precision, and ability to differentiate participants with and without PFPS. The selected sEMG parameter associated with anterior knee pain was considered as an index test and was compared with the reference standard for the diagnosis of PFPS. Intraclass correlation coefficient, SEM, independent t tests, sensitivity, specificity, negative and positive likelihood ratios, and negative and positive predictive values were used for the statistical analysis. The medium-frequency band (B2) parameter was reliable (intraclass correlation coefficient=.80-.90), precise (SEM=2.71-3.87 normalized unit), and able to differentiate participants with and without PFPS (Ppain showed positive diagnostic accuracy values (specificity, .87; sensitivity, .70; negative likelihood ratio, .33; positive likelihood ratio, 5.63; negative predictive value, .72; and positive predictive value, .86). The results provide evidence to support the use of EMG signals (B2-frequency band of 45-96 Hz) of the vastus lateralis and vastus medialis muscles with referred anterior knee pain in the diagnosis of PFPS. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Oral muscles are progressively affected in Duchenne muscular dystrophy: implications for dysphagia treatment.

Science.gov (United States)

van den Engel-Hoek, Lenie; Erasmus, Corrie E; Hendriks, Jan C M; Geurts, Alexander C H; Klein, Willemijn M; Pillen, Sigrid; Sie, Lilian T; de Swart, Bert J M; de Groot, Imelda J M

2013-05-01

Dysphagia is reported in advanced stages of Duchenne muscular dystrophy (DMD). The population of DMD is changing due to an increasing survival. We aimed to describe the dysphagia in consecutive stages and to assess the underlying mechanisms of dysphagia in DMD, in order to develop mechanism based recommendations for safe swallowing. In this cross-sectional study, participants were divided into: early and late ambulatory stage (AS, n = 6), early non-ambulatory stage (ENAS, n = 7), and late non-ambulatory stage (LNAS, n = 11). Quantitative oral muscle ultrasound was performed to quantify echo intensity. Swallowing was assessed with a video fluoroscopic swallow study, surface electromyography (sEMG) of the submental muscle group and tongue pressure. Differences in outcome parameters among the three DMD stages were tested with analysis of variance. Oral muscles related to swallowing were progressively affected, starting in the AS with the geniohyoid muscle. Tongue (pseudo) hypertrophy was found in 70 % of patients in the ENAS and LNAS. Oral phase problems and post-swallow residue were observed, mostly in the LNAS with solid food. sEMG and tongue pressure data of swallowing solid food revealed the lowest sEMG amplitude, the longest duration and lowest tongue pressure in the LNAS. In case of swallowing problems in DMD, based on the disturbed mechanisms of swallowing, it is suggested to (1) adjust meals in terms of less solid food, and (2) drink water after meals to clear the oropharyngeal area.

Electromyographic analysis of superior orbicularis oris muscle function in children surgically treated for unilateral complete cleft lip and palate.

Science.gov (United States)

Szyszka-Sommerfeld, Liliana; Woźniak, Krzysztof; Matthews-Brzozowska, Teresa; Kawala, Beata; Mikulewicz, Marcin

2017-09-01

The aim of this study was to assess the electrical activity of the superior orbicularis oris muscle in children surgically treated for unilateral complete cleft lip and palate (UCCLP). The sample comprised 45 patients 6.38-12.68 years of age with UCCLP and 40 subjects 6.61-11.71 years of age with no clefts. Electromyographical (EMG) recordings were taken with a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the rest position and during saliva swallowing, lip protrusion and reciprocal compression of the lips, as well as while producing the phonemes /p/, /b/, and /m/ combined with the vowel /a/. The electrical activity of the upper lip during saliva swallowing and lip compression was significantly greater in the cleft group. Similar resting level activity was observed in both groups. During the production of the /p/, /b/, and /m/ phonemes combined with the vowel /a/ the results showed no significant differences in the EMG activity between children with UCCLP and noncleft subjects. Patients with UCCLP have abnormal upper lip function characterized by increased activity of the superior orbicularis oris muscle during saliva swallowing and lip compression, and this may affect facial morphology. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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.

Effects of experimental occlusal interference on body posture: an optoelectronic stereophotogrammetric analysis.

Science.gov (United States)

Marini, I; Gatto, M R; Bartolucci, M L; Bortolotti, F; Alessandri Bonetti, G; Michelotti, A

2013-07-01

In recent years, there has been increasing interest in the relationship between dental occlusion and body posture both among people and in scientific literature. The aim of the present longitudinal study is to investigate the effects of an experimental occlusal interference on body posture by means of a force platform and an optoelectronic stereophotogrammetric analysis. An occlusal interference of a 0- to 2-mm-thick glass composite was prepared to disturb the intercuspal position while not creating interference during lateral or protrusive mandibular excursions. Frontal and sagittal kinematic parameters, dynamic gait measurements and superficial electromyographic (SEMG) activity of head and neck muscles were performed on 12 healthy subjects. Measurements were taken 10 days before the application of the occlusal interference, and then immediately before the application, the day after it, and at a distance of 7 and 14 days under four different exteroceptive conditions. The outcomes of this study show that an occlusal interference does not modify significantly over time static and dynamic parameters of body posture under different exteroceptive conditions. It has a minimal influence only on the frontal kinematic parameters related to mandibular position, and it induces a transient increase of the activity of masticatory muscles. In this study, the experimental occlusal interference did not significantly influence the body posture during a 14-day follow-up period. © 2013 John Wiley & Sons Ltd.

Improved prosthetic hand control with concurrent use of myoelectric and inertial measurements

OpenAIRE

Krasoulis, Agamemnon; Kyranou, Iris; Erden, Mustapha Suphi; Nazarpour, Kianoush; Vijayakumar, Sethu

2017-01-01

Background Myoelectric pattern recognition systems can decode movement intention to drive upper-limb prostheses. Despite recent advances in academic research, the commercial adoption of such systems remains low. This limitation is mainly due to the lack of classification robustness and a simultaneous requirement for a large number of electromyogram (EMG) electrodes. We propose to address these two issues by using a multi-modal approach which combines surface electromyography (sEMG) with inert...

Neurophysiological aspects of eye and eyelid movements during blinking in humans

NARCIS (Netherlands)

Bour, L. J.; Aramideh, M.; de Visser, B. W.

2000-01-01

The neural relationships between eyelid movements and eye movements during spontaneous, voluntary, and reflex blinking in a group of healthy subjects were examined. Electromyographic (EMG) recording of the orbicularis oculi (OO) muscles was performed using surface electrodes. Concurrently,

Hamstring Activity in the Anterior Cruciate Ligament Injured Patient: Injury Implications and Comparison With Quadriceps Activity.

Science.gov (United States)

Frank, Rachel M; Lundberg, Hannah; Wimmer, Markus A; Forsythe, Brian; Bach, Bernard R; Verma, Nikhil N; Cole, Brian J

2016-08-01

To investigate the potential causes of diminished knee extension after acute anterior cruciate ligament (ACL) injury using both surface electromyography (sEMG) analysis of the quadriceps and hamstrings, and gait analysis to assess muscle action and tone. Consecutive patients with an acute ACL tear underwent sEMG and gait analysis within 2 weeks of injury, before ACL reconstruction. Standard motion analysis techniques were used and sEMG data were collected simultaneously with gait data. T-tests were used to determine differences between the ACL-deficient and control subjects in knee flexion angles, peak external knee joint moments, and total time that a muscle was activated ("on") during gait. External knee moments were expressed as a percentage of body weight times height. Ten patients (mean age 24 ± 4 years) were included at a mean 10.2 days between injury and analysis; 10 uninjured, matched control subjects were included for comparison. There were significant increases in minimum flexion angle at heel strike (5.92 ± 3.39 v -3.49 ± 4.55, P hamstring activity "on" time during gait (P > .05). In patients with acute ACL injury, the ACL-deficient limb does not reach as much extension as controls. Although the rectus femoris is "on" for shorter periods during the gait cycle, there is no difference in hamstring time on during gait. This information may help clinicians better understand muscle function and gait patterns in the acute time period after ACL injury. Level III, case control study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Immediate effects of neuromuscular joint facilitation intervention after anterior cruciate ligament reconstruction.

Science.gov (United States)

Wang, Lei

2016-07-01

[Purpose] The aim of this study was to examine the immediate effects of neuromuscular joint facilitation (NJF) on the functional activity level after rehabilitation of anterior cruciate ligament (ACL) reconstruction. [Subjects and Methods] Ten young subjects (8 males and 2 females) who underwent ACL reconstruction were included in the study. The subjects were divided into two groups, namely, knee joint extension muscle strength training (MST) group and knee joint extension outside rotation pattern of NJF group. Extension strength was measured in both groups before and after the experiment. Surface electromyography (sEMG) of the vastus medialis and vastus lateralis muscles and joint position error (JPE) test of the knee joint were also conducted. [Results] JPE test results and extension strength measurements in the NJF group were improved compared with those in the MST group. Moreover, the average discharge of the vastus medialis and vastus lateralis muscles on sEMG in the NJF group was significantly increased after MST and NJF treatments. [Conclusion] The obtained results suggest that NJF training in patients with ACL reconstruction can improve knee proprioception ability and muscle strength.

Neurocontrol of the inverse dynamics in functional electrical stimulation

NARCIS (Netherlands)

Spaanenburg, L; Nijhuis, JAG; Ypma, A; Silva, FL; Principe, JC; Almeida, LB

1997-01-01

The rehabilitation of paraplegia can be pursued by functional electrical stimulation (FES) combined with biofeedback This requires control by surface electromyographical (EMG) signals to predict the muscle stimulation patterns while compensating the inherent phase lag. This can be realized by a

Tibialis posterior in health and disease: a review of structure and function with specific reference to electromyographic studies

Directory of Open Access Journals (Sweden)

Woodburn James

2009-08-01

Full Text Available Abstract Tibialis posterior has a vital role during gait as the primary dynamic stabiliser of the medial longitudinal arch; however, the muscle and tendon are prone to dysfunction with several conditions. We present an overview of tibialis posterior muscle and tendon anatomy with images from cadaveric work on fresh frozen limbs and a review of current evidence that define normal and abnormal tibialis posterior muscle activation during gait. A video is available that demonstrates ultrasound guided intra-muscular insertion techniques for tibialis posterior electromyography. Current electromyography literature indicates tibialis posterior intensity and timing during walking is variable in healthy adults and has a disease-specific activation profile among different pathologies. Flat-arched foot posture and tibialis posterior tendon dysfunction are associated with greater tibialis posterior muscle activity during stance phase, compared to normal or healthy participants, respectively. Cerebral palsy is associated with four potentially abnormal profiles during the entire gait cycle; however it is unclear how these profiles are defined as these studies lack control groups that characterise electromyographic activity from developmentally normal children. Intervention studies show antipronation taping to significantly decrease tibialis posterior muscle activation during walking compared to barefoot, although this research is based on only four participants. However, other interventions such as foot orthoses and footwear do not appear to systematically effect muscle activation during walking or running, respectively. This review highlights deficits in current evidence and provides suggestions for the future research agenda.

The implementation of quantitative electromyographic neuromuscular monitoring in an academic anesthesia department.

Science.gov (United States)

Todd, Michael M; Hindman, Bradley J; King, Brian J

2014-08-01

December 2012), and there have been no cases of NMB-related reintubations in the PACU during the last 2 years. Implementation of universal electromyographic-based quantitative neuromuscular blockade monitoring required a sustained process of education along with repeated PACU surveys and feedback to providers. Nevertheless, this effort resulted in a significant reduction in the incidence of incompletely reversed patients in the PACU.

Estimation of continuous multi-DOF finger joint kinematics from surface EMG using a multi-output Gaussian Process.

Science.gov (United States)

Ngeo, Jimson; Tamei, Tomoya; Shibata, Tomohiro

2014-01-01

Surface electromyographic (EMG) signals have often been used in estimating upper and lower limb dynamics and kinematics for the purpose of controlling robotic devices such as robot prosthesis and finger exoskeletons. However, in estimating multiple and a high number of degrees-of-freedom (DOF) kinematics from EMG, output DOFs are usually estimated independently. In this study, we estimate finger joint kinematics from EMG signals using a multi-output convolved Gaussian Process (Multi-output Full GP) that considers dependencies between outputs. We show that estimation of finger joints from muscle activation inputs can be improved by using a regression model that considers inherent coupling or correlation within the hand and finger joints. We also provide a comparison of estimation performance between different regression methods, such as Artificial Neural Networks (ANN) which is used by many of the related studies. We show that using a multi-output GP gives improved estimation compared to multi-output ANN and even dedicated or independent regression models.

Effect of mini-implant-supported mandibular overdentures on electromyographic activity of the masseter muscle during chewing of hard and soft food.

Science.gov (United States)

Ashmawy, Tarek Mohy; El Talawy, Dina Bahgat; Shaheen, Nasser Hussein

2014-09-01

To objectively evaluate the effect of mini-implant- supported mandibular overdentures on electromyographic activity (EMG) of the masseter muscle during chewing of hard and soft foods. Twelve completely edentulous patients (4 females and 8 males) with maladaptive experience of wearing mandibular dentures received new maxillary and mandibular dentures. After 3 months of adaptation, four mini dental implants (MDIs) were inserted in the interforaminal region of the mandible, and the new mandibular dentures were connected to the implants immediately with O/ring attachments. The activity of masseter muscle (EMG) and the duration of chewing cycle were measured during chewing hard (carrot) and soft (gum) foods. The measurements were made 3 months after wearing each of the following prostheses: the new conventional dentures; and the MDI-retained mandibular overdentures. The EMG of masseter muscle increased and the DC decreased with MDI-retained mandibular overdentures when compared to conventional dentures. Hard food (carrot) was associated with increased EMG and decreased DC when compared to soft food (gum) for both conventional dentures and MDI-retained mandibular overdentures. Mini-implant-supported mandibular overdentures are associated with increased activity of masseter muscle and decreased duration of chewing cycle for both hard and soft foods when compared to conventional dentures.

L4-L5-S1 human dermatomes: a clinical, electromyographical, imaging and surgical findings Dermátomos humanos L4, L5 e S1: achados clínicos, eletromiográficos, de imagem e cirúrgicos

Directory of Open Access Journals (Sweden)

Antonio Tadeu de Souza Faleiros

2009-06-01

Full Text Available There is substantial controversy in literature about human dermatomes. We studied L4, L5, and S1 inferior limb dermatomes by comparing clinical signs and symptoms with conduction studies, electromyographical data, neurosurgical findings, and imaging data from computerized tomography (CT or magnetic resonance imaging (MRI. After analyzing 60 patients, we concluded that L4 is probably located in the medial aspect of the leg, L5 in the lateral aspect of the leg and foot dorsus, and S1 in the posterior aspect of the backside, tight, leg and plantar foot skin. This is the first time that these human dermatomes have been evaluated by combined analysis of clinical, electromyographical, neurosurgical, and imaging data.Há controvérsia na literatura sobre os dermátomos humanos. Estudamos dermátomos do membro inferior comparando sinais e sintomas com estudos eletromiográficos, de imagem e achados cirúrgicos. Analisando 60 pacientes, concluímos que o dermátomo L4 provavelmente está localizado na região medial da perna, o dermátomo L5 na região lateral da perna e dorso do pé, e o dermátomo S1 na nádega, região posterior da coxa e da perna e na região plantar. Este é o primeiro estudo que os dermátomos do membro inferior foram analisados através de dados clínicos, eletromiográficos, imagem e achados cirúrgicos.

Electromyographic Comparison of Barbell Deadlift, Hex Bar Deadlift, and Hip Thrust Exercises: A Cross-Over Study.

Science.gov (United States)

Andersen, Vidar; Fimland, Marius S; Mo, Dag-Andrè; Iversen, Vegard M; Vederhus, Torbjørn; Rockland Hellebø, Lars R; Nordaune, Kristina I; Saeterbakken, Atle H

2018-03-01

Andersen, V, Fimland, MS, Mo, D-A, Iversen, VM, Vederhus, T, Rockland Hellebø, LR, Nordaune, KI, and Saeterbakken, AH. Electromyographic comparison of barbell deadlift, hex bar deadlift, and hip thrust exercises: a cross-over study. J Strength Cond Res 32(3): 587-593, 2018-The aim of the study was to compare the muscle activation level of the gluteus maximus, biceps femoris, and erector spinae in the hip thrust, barbell deadlift, and hex bar deadlift; each of which are compound resisted hip extension exercises. After 2 familiarization sessions, 13 resistance-trained men performed a 1 repetition maximum in all 3 exercises in 1 session, in randomized and counterbalanced order. The whole ascending movement (concentric phase), as well as its lower and upper parts (whole movement divided in 2), were analyzed. The hip thrust induced greater activation of the gluteus maximus compared with the hex bar deadlift in the whole (16%, p = 0.025) and the upper part (26%, p = 0.015) of the movement. For the whole movement, the biceps femoris was more activated during barbell deadlift compared with both the hex bar deadlift (28%, p bar deadlift (p = 0.049) compared with hip thrust. Biceps femoris activation in the upper part of the movement was 39% higher for the barbell deadlift compared with the hex bar deadlift (p = 0.001) and 34% higher for the hip thrust compared with the hex bar deadlift (p = 0.002). No differences were displayed for the erector spinae activation (p = 0.312-0.859). In conclusion, the barbell deadlift was clearly superior in activating the biceps femoris compared with the hex bar deadlift and hip thrust, whereas the hip thrust provided the highest gluteus maximus activation.

Firing patterns of spontaneously active motor units in spinal cord-injured subjects

NARCIS (Netherlands)

Zijdewind, Inge; Thomas, Christine K.

Involuntary motor unit activity at low rates is common in hand muscles paralysed by spinal cord injury. Our aim was to describe these patterns of motor unit behaviour in relation to motoneurone and motor unit properties. Intramuscular electromyographic activity (EMG), surface EMG and force were

Wireless sEMG-Based Body-Machine Interface for Assistive Technology Devices.

Science.gov (United States)

Fall, Cheikh Latyr; Gagnon-Turcotte, Gabriel; Dube, Jean-Francois; Gagne, Jean Simon; Delisle, Yanick; Campeau-Lecours, Alexandre; Gosselin, Clement; Gosselin, Benoit

2017-07-01

Assistive technology (AT) tools and appliances are being more and more widely used and developed worldwide to improve the autonomy of people living with disabilities and ease the interaction with their environment. This paper describes an intuitive and wireless surface electromyography (sEMG) based body-machine interface for AT tools. Spinal cord injuries at C5-C8 levels affect patients' arms, forearms, hands, and fingers control. Thus, using classical AT control interfaces (keypads, joysticks, etc.) is often difficult or impossible. The proposed system reads the AT users' residual functional capacities through their sEMG activity, and converts them into appropriate commands using a threshold-based control algorithm. It has proven to be suitable as a control alternative for assistive devices and has been tested with the JACO arm, an articulated assistive device of which the vocation is to help people living with upper-body disabilities in their daily life activities. The wireless prototype, the architecture of which is based on a 3-channel sEMG measurement system and a 915-MHz wireless transceiver built around a low-power microcontroller, uses low-cost off-the-shelf commercial components. The embedded controller is compared with JACO's regular joystick-based interface, using combinations of forearm, pectoral, masseter, and trapeze muscles. The measured index of performance values is 0.88, 0.51, and 0.41 bits/s, respectively, for correlation coefficients with the Fitt's model of 0.75, 0.85, and 0.67. These results demonstrate that the proposed controller offers an attractive alternative to conventional interfaces, such as joystick devices, for upper-body disabled people using ATs such as JACO.

Immediate effect of laryngeal surface electrical stimulation on swallowing performance.

Science.gov (United States)

Takahashi, Keizo; Hori, Kazuhiro; Hayashi, Hirokazu; Fujiu-Kurachi, Masako; Ono, Takahiro; Tsujimura, Takanori; Magara, Jin; Inoue, Makoto

2018-01-01

Surface electrical stimulation of the laryngeal region is used to improve swallowing in dysphagic patients. However, little is known about how electrical stimulation affects tongue movements and related functions. We investigated the effect of electrical stimulation on tongue pressure and hyoid movement, as well as suprahyoid and infrahyoid muscle activity, in 18 healthy young participants. Electrical stimulation (0.2-ms duration, 80 Hz, 80% of each participant's maximal tolerance) of the laryngeal region was applied. Each subject swallowed 5 ml of barium sulfate liquid 36 times at 10-s intervals. During the middle 2 min, electrical stimulation was delivered. Tongue pressure, electromyographic activity of the suprahyoid and infrahyoid muscles, and videofluorographic images were simultaneously recorded. Tongue pressure during stimulation was significantly lower than before or after stimulation and was significantly greater after stimulation than at baseline. Suprahyoid activity after stimulation was larger than at baseline, while infrahyoid muscle activity did not change. During stimulation, the position of the hyoid at rest was descended, the highest hyoid position was significantly inferior, and the vertical movement was greater than before or after stimulation. After stimulation, the positions of the hyoid at rest and at the maximum elevation were more superior than before stimulation. The deviation of the highest positions of the hyoid before and after stimulation corresponded to the differences in tongue pressures at those times. These results suggest that surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. NEW & NOTEWORTHY Surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. Tongue muscles may contribute to overshot recovery

Adaptations of upper trapezius muscle activity during sustained contractions in women with fibromyalgia

DEFF Research Database (Denmark)

Falla, Deborah Lorraine; Andersen, Helle; Danneskiold-Samsøe, Bente

2010-01-01

The study compared the distribution of electromyographic (EMG) signal amplitude in the upper trapezius muscle in 10 women with fibromyalgia and in 10 healthy women before and after experimentally-induced muscle pain. Surface EMG signals were recorded over the right upper trapezius muscle with a 10...

Selection of suitable hand gestures for reliable myoelectric human computer interface.

Science.gov (United States)

Castro, Maria Claudia F; Arjunan, Sridhar P; Kumar, Dinesh K

2015-04-09

Myoelectric controlled prosthetic hand requires machine based identification of hand gestures using surface electromyogram (sEMG) recorded from the forearm muscles. This study has observed that a sub-set of the hand gestures have to be selected for an accurate automated hand gesture recognition, and reports a method to select these gestures to maximize the sensitivity and specificity. Experiments were conducted where sEMG was recorded from the muscles of the forearm while subjects performed hand gestures and then was classified off-line. The performances of ten gestures were ranked using the proposed Positive-Negative Performance Measurement Index (PNM), generated by a series of confusion matrices. When using all the ten gestures, the sensitivity and specificity was 80.0% and 97.8%. After ranking the gestures using the PNM, six gestures were selected and these gave sensitivity and specificity greater than 95% (96.5% and 99.3%); Hand open, Hand close, Little finger flexion, Ring finger flexion, Middle finger flexion and Thumb flexion. This work has shown that reliable myoelectric based human computer interface systems require careful selection of the gestures that have to be recognized and without such selection, the reliability is poor.

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.

EMG evaluation of hip adduction exercises for soccer players

DEFF Research Database (Denmark)

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

2014-01-01

INTRODUCTION: 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. OBJECTIVE: 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. 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...

Intraoperative Mapping and Monitoring for Rootlets of the Lower Cranial Nerves Related to Vocal Cord Movement.

Science.gov (United States)

Wanibuchi, Masahiko; Akiyama, Yukinori; Mikami, Takeshi; Komatsu, Katsuya; Sugino, Toshiya; Suzuki, Kengo; Kanno, Aya; Ohtaki, Shunya; Noshiro, Shouhei; Mikuni, Nobuhiro

2016-06-01

Damage to the motor division of the lower cranial nerves that run into the jugular foramen leads to hoarseness, dysphagia, and the risk of aspiration pneumonia; therefore, its functional preservation during surgical procedures is important. Intraoperative mapping and monitoring of the motor rootlets at the cerebellomedullary cistern using endotracheal tube electrodes is a safe and effective procedure to prevent its injury. To study the location of the somatic and autonomic motor fibers of the lower cranial nerves related to vocal cord movement. Twenty-four patients with pathologies at the cerebellopontine lesion were studied. General anesthesia was maintained with fentanyl and propofol. A monopolar stimulator was used at amplitudes of 0.05 to 0.1 mA. Both acoustic and visual signals were displayed as vocalis muscle electromyographic activity using endotracheal tube surface electrodes. The average number of rootlets was 7.4 (range, 5-10); 75% of patients had 7 or 8 rootlets. As many as 6 rootlets (2-4 in most cases) were responsive in each patient. In 23 of the 24 patients, the responding rootlets congregated on the caudal side. The maximum electromyographic response was predominantly in the most caudal or second most caudal rootlet in 79%. The majority of motor fibers of the lower cranial nerves run through the caudal part of the rootlets at the cerebellomedullary cistern, and the maximal electromyographic response was elicited at the most caudal or second most caudal rootlet. EMG, electromyographic.

Electromyographic preactivation pattern of the gluteus medius during weight-bearing functional tasks in women with and without anterior knee pain.

Science.gov (United States)

Nakagawa, Theresa H; Muniz, Thiago B; Baldon, Rodrigo M; Maciel, Carlos D; Amorim, César F; Serrão, Fábio V

2011-01-01

Proximal factors have been proposed to influence the biomechanics of the patellofemoral joint. A delayed or diminished gluteus medius (GM) activation, before the foot contact on the ground during functional activities could lead to excessive femur adduction and internal rotation and be associated with anterior knee pain (AKP). There are few studies on this topic and the results were inconclusive, therefore, it is necessary to investigate the GM preactivation pattern during functional activities. To compare the GM electromyographic (EMG) preactivation pattern during walking, descending stairs and in single leg jump task in women with and without AKP. Nine women clinically diagnosed with AKP and ten control subjects with no history of knee injury participated in this study. We evaluated GM EMG linear envelope before the foot contact on the ground during walking and GM onset time and EMG linear envelope during descending stairs as well as in a single leg vertical jump. Mann-Whitney U tests were used to determine the between-group differences in GM EMG preactivation pattern. No between-group differences were observed in GM linear envelope during walking (P=0.41), GM onset time and linear envelope during descending stairs (P=0.17 and P=0.15) and single leg jump (P=0.81 and P=0.33). Women with AKP did not demonstrated altered GM preactivation pattern during functional weight bearing activities. Our results did not support the hypothesis that poor GM preactivation pattern could be associated with AKP.

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.

The Ninapro database: A resource for sEMG naturally controlled robotic hand prosthetics.

Science.gov (United States)

Atzori, Manfredo; Muller, Henning

2015-01-01

The dexterous natural control of robotic prosthetic hands with non-invasive techniques is still a challenge: surface electromyography gives some control capabilities but these are limited, often not natural and require long training times; the application of pattern recognition techniques recently started to be applied in practice. While results in the scientific literature are promising they have to be improved to reach the real needs. The Ninapro database aims to improve the field of naturally controlled robotic hand prosthetics by permitting to worldwide research groups to develop and test movement recognition and force control algorithms on a benchmark database. Currently, the Ninapro database includes data from 67 intact subjects and 11 amputated subject performing approximately 50 different movements. The data are aimed at permitting the study of the relationships between surface electromyography, kinematics and dynamics. The Ninapro acquisition protocol was created in order to be easy to be reproduced. Currently, the number of datasets included in the database is increasing thanks to the collaboration of several research groups.

Spectral analysis of the electromyograph of the erector spinae muscle before and after a dynamic manual load-lifting test

Directory of Open Access Journals (Sweden)

A.C. Cardozo

2004-07-01

Full Text Available The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (± SD were 20 ± 1 years, 1.6 ± 0.03 m, and 53 ± 4 kg, respectively. The development of muscle fatigue was assessed by spectral analysis (median frequency and root mean square with time. The test consisted of repeated bending movements from the trunk, starting from a 45º angle of flexion, with the application of approximately 15, 25 and 50% of maximum individual load, to the stand up position. The protocol used proved to be more reliable with loads exceeding 50% of the maximum for the identification of muscle fatigue by electromyography as a function of time. Most of the volunteers showed an increase in root mean square versus time on both the right (N = 7 and the left (N = 6 side, indicating a tendency to become fatigued. With respect to the changes in median frequency of the electromyographic signal, the loads used in this study had no significant effect on either the right or the left side of the erector spinae muscle at this frequency, suggesting that a higher amount and percentage of loads would produce more substantial results in the study of isotonic contractions.

Brain-muscle-computer interface: mobile-phone prototype development and testing.

Science.gov (United States)

Vernon, Scott; Joshi, Sanjay S

2011-07-01

We report prototype development and testing of a new mobile-phone-based brain-muscle-computer interface for severely paralyzed persons, based on previous results from our group showing that humans may actively create specified power levels in two separate frequency bands of a single surface electromyography (sEMG) signal. EMG activity on the surface of a single face muscle site (auricularis superior) is recorded with a standard electrode. This analog electrical signal is imported into an Android-based mobile phone and digitized via an internal A/D converter. The digital signal is split, and then simultaneously filtered with two band-pass filters to extract total power within two separate frequency bands. The user-modulated power in each frequency band serves as two separate control channels for machine control. After signal processing, the Android phone sends commands to external devices via a Bluetooth interface. Users are trained to use the device via visually based operant conditioning, with simple cursor-to-target activities on the phone screen. The mobile-phone prototype interface is formally evaluated on a single advanced Spinal Muscle Atrophy subject, who has successfully used the interface in his home in evaluation trials and for remote control of a television. Development of this new device will not only guide future interface design for community use, but will also serve as an information technology bridge for in situ data collection to quantify human sEMG manipulation abilities for a relevant population.

Hamstring injury prevention in soccer: Before or after training?

Science.gov (United States)

Lovell, R; Knox, M; Weston, M; Siegler, J C; Brennan, S; Marshall, P W M

2018-02-01

We examined the effects of a 12-week program of Nordic hamstring exercises (NHE), administered before or after football training, upon eccentric hamstring strength, muscle activity, and architectural adaptations. Amateur soccer players were randomized into three groups. The control group (CON; n=11) undertook core stability exercises, whereas a periodized NHE program was delivered either before (NHE BEF ; n=10) or after (NHE AFT ; n=14) biweekly training sessions. Outcome measures included peak torque and concomitant normalized peak surface electromyography signals (sEMG) of the biceps femoris (BF) and medial hamstring (MH) muscles during knee flexor maximal eccentric contractions, performed at 30°·s -1 . Ultrasonography was used to determine BF muscle thickness, muscle fiber pennation angle, and fascicle length. Performing the NHE derived likely moderate peak torque increases in both NHE BEF (+11.9%; 90% confidence interval: 3.6%-20.9%) and NHE AFT (+11.6%; 2.6%-21.5%) vs CON. Maximum sEMG increases were moderately greater in the BF of both NHE training groups vs CON. There were likely moderate increases in BF muscle thickness (+0.17 cm; 0.05-0.29 cm) and likely small pennation angle increases (+1.03°; -0.08° to 2.14°) in NHE AFT vs CON and NHE BEF . BF fascicle length increases were likely greater in NHE BEF (+1.58 cm; 0.48-2.68 cm; small effect) vs CON and NHE AFT . A 12-week eccentric hamstring strengthening program increased strength and sEMG to a similar magnitude irrespective of its scheduling relative to the football training session. However, architectural adaptations to support the strength gains differed according to the timing of the injury prevention program. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Pelvic floor muscle assessment outcomes in women with and without provoked vestibulodynia and the impact of a physical therapy program.

Science.gov (United States)

Gentilcore-Saulnier, Evelyne; McLean, Linda; Goldfinger, Corrie; Pukall, Caroline F; Chamberlain, Susan

2010-02-01

Physical therapy (PT) may reduce the pain associated with provoked vestibulodynia (PVD) based on previous findings that pelvic floor muscle dysfunction (PFMD) is associated with PVD symptoms. The goals of this study were: (i) to determine whether women with and without PVD differ on measures of pelvic floor muscle (PFM) behavior; and (ii) to assess the impact of PT treatment for women with PVD on these measures. Eleven women with PVD and 11 control women completed an assessment evaluating PFM behavior using surface electromyography (SEMG) recordings and a digital intravaginal assessment. Women with PVD repeated the assessment after they had undergone eight PT treatment sessions of manual therapy, biofeedback, electrical stimulation, dilator insertions, and home exercises. Superficial and deep PFM SEMG tonic activity and phasic activity in response to a painful pressure stimulus, PFM digital assessment variables (tone, flexibility, relaxation capacity, and strength). At pretreatment, women with PVD had higher tonic SEMG activity in their superficial PFMs compared with the control group, whereas no differences were found in the deep PFMs. Both groups demonstrated contractile responses to the painful pressure stimulus that were significantly higher in the superficial as compared with the deep PFMs, with the responses in the PVD group being higher than those in control women. Women with PVD had higher PFM tone, decreased PFM flexibility and lower PFM relaxation capacity compared with control women. Posttreatment improvements included less PFM responsiveness to pain, less PFM tone, improved vaginal flexibility, and improved PFM relaxation capacity, such that women with PVD no longer differed from controls on these measures. Women with PVD demonstrated altered PFM behavior when compared with controls, providing empirical evidence of PFMD, especially at the superficial layer. A PT rehabilitation program specifically targeting PFMD normalized PFM behavior in women with PVD.

New Swallowing Evaluation Using Piezoelectricity in Normal Individuals.

Science.gov (United States)

Sogawa, Yuichiro; Kimura, Shinji; Harigai, Toru; Sakurai, Naoki; Toyosato, Akira; Nishikawa, Taro; Inoue, Makoto; Murasawa, Akira; Endo, Naoto

2015-12-01

This study aimed to elucidate the relationship between the piezoelectric waveform latency, hyoid bone movement, surface electromyogram (sEMG), and the pharyngeal transit time (PTT) during swallowing. Forty-one healthy subjects were divided into three age groups: younger (20-39 years, n = 8), middle-aged (40-59 years, n = 9), and older (60-79 years, n = 24). Motion analysis of the hyoid bone using videofluorography (VF), waveform analysis of the front neck using piezoelectric films, and sEMG of the suprahyoid muscle group were performed simultaneously. Latencies of the three movement phases were defined as upward (VFS1), forward (VFS2), and returning to starting position (VFS3). The three phases of the piezoelectric waveform-from wave initiation of the negative wave to the start of the second deep negative wave; from the start of the second deep negative wave to the start of the last positive wave (SLPW); and from the SLPW to the end of the last positive wave-were defined as PS1, PS2, and PS3, respectively. VFS1-3 and PS1-3 were significantly correlated. VFS1 and PS1 latencies were significantly longer with thick liquid than with thin liquid. VFS2, PS1, and PS2 latencies were longer in the older group than in the other two groups. The start of PS1 was nearly equal to those of sEMG and VFS1. Bolus arrival time in the valleculae was statistically equal to the end of the PS1 with both thin and thick liquids. To establish the swallowing screening using Piezoelectric film, further investigation is necessary in the dysphagia patients.

Feasibility and safety of early lower limb robot-assisted training in sub-acute stroke patients: a pilot study.

Science.gov (United States)

Gandolfi, Marialuisa; Geroin, Christian; Tomelleri, Christopher; Maddalena, Isacco; Kirilova Dimitrova, Eleonora; Picelli, Alessandro; Smania, Nicola; Waldner, Andreas

2017-12-01

So far, the development of robotic devices for the early lower limb mobilization in the sub-acute phase after stroke has received limited attention. To explore the feasibility of a newly robotic-stationary gait training in sub-acute stroke patients. To report the training effects on lower limb function and muscle activation. A pilot study. Rehabilitation ward. Two sub-acute stroke inpatients and ten age-matched healthy controls were enrolled. Healthy controls served as normative data. Patients underwent 10 robot-assisted training sessions (20 minutes, 5 days/week) in alternating stepping movements (500 repetitions/session) on a hospital bed in addition to conventional rehabilitation. Feasibility outcome measures were compliance, physiotherapist time, and responses to self-report questionnaires. Efficacy outcomes were bilateral lower limb muscle activation pattern as measured by surface electromyography (sEMG), Motricity Index (MI), Medical Research Council (MRC) grade, and Ashworth Scale (AS) scores before and after training. No adverse events occurred. No significant differences in sEMG activity between patients and healthy controls were observed. Post-training improvement in MI and MRC scores, but no significant changes in AS scores, were recorded. Post-treatment sEMG analysis of muscle activation patterns showed a significant delay in rectus femoris offset (P=0.02) and prolonged duration of biceps femoris (P=0.04) compared to pretreatment. The robot-assisted training with our device was feasible and safe. It induced physiological muscle activations pattern in both stroke patients and healthy controls. Full-scale studies are needed to explore its potential role in post-stroke recovery. This robotic device may enrich early rehabilitation in subacute stroke patients by inducing physiological muscle activation patterns. Future studies are warranted to evaluate its effects on promoting restorative mechanisms involved in lower limb recovery after stroke.

Upper Limb Static-Stretching Protocol Decreases Maximal Concentric Jump Performance

Directory of Open Access Journals (Sweden)

Paulo H. Marchetti

2014-12-01

Full Text Available The purpose of the present study was to evaluate the acute effects of an upper limb static-stretching (SS protocol on the maximal concentric jump performance. We recruited 25 young healthy, male, resistance trained individuals (stretched group, n = 15 and control group, n = 10 in this study. The randomized between group experimental protocol consisted of a three trials of maximal concentric jump task, before and after a SS of the upper limb. Vertical ground reaction forces (vGRF and surface electromyography (sEMG of both gastrocnemius lateralis (GL and vastus lateralis (VL were acquired. An extensive SS was employed consisting of ten stretches of 30 seconds, with 15 seconds of rest, and 70-90% of the point of discomfort (POD. ANOVA (2x2 (group x condition was used for shoulder joint range of motion (ROM, vGRF and sEMG. A significant interaction for passive ROM of the shoulder joint revealed significant increases between pre- and post-SS protocol (p < 0.001. A significant interaction demonstrated decreased peak force and an increased peak propulsion duration between pre- and post-stretching only for stretch group (p = 0.021, and p = 0.024, respectively. There was a significant main effect between groups (stretch and control for peak force for control group (p = 0.045. Regarding sEMG variables, there were no significant differences between groups (control versus stretched or condition (pre-stretching versus post-stretching for the peak amplitude of RMS and IEMG for both muscles (VL and GL. In conclusion, an acute extensive SS can increase the shoulder ROM, and negatively affect both the propulsion duration and peak force of the maximal concentric jump, without providing significant changes in muscle activation.

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.

[Design of an embedded stroke rehabilitation apparatus system based on Linux computer engineering].

Science.gov (United States)

Zhuang, Pengfei; Tian, XueLong; Zhu, Lin

2014-04-01

A realizaton project of electrical stimulator aimed at motor dysfunction of stroke is proposed in this paper. Based on neurophysiological biofeedback, this system, using an ARM9 S3C2440 as the core processor, integrates collection and display of surface electromyography (sEMG) signal, as well as neuromuscular electrical stimulation (NMES) into one system. By embedding Linux system, the project is able to use Qt/Embedded as a graphical interface design tool to accomplish the design of stroke rehabilitation apparatus. Experiments showed that this system worked well.

Testing of motor unit synchronization model for localized muscle fatigue.

Science.gov (United States)

Naik, Ganesh R; Kumar, Dinesh K; Yadav, Vivek; Wheeler, Katherine; Arjunan, Sridhar

2009-01-01

Spectral compression of surface electromyogram (sEMG) is associated with onset of localized muscle fatigue. The spectral compression has been explained based on motor unit synchronization theory. According to this theory, motor units are pseudo randomly excited during muscle contraction, and with the onset of muscle fatigue the recruitment pattern changes such that motor unit firings become more synchronized. While this is widely accepted, there is little experimental proof of this phenomenon. This paper has used source dependence measures developed in research related to independent component analysis (ICA) to test this theory.

sEMG-Based Gesture Recognition with Convolution Neural Networks

Directory of Open Access Journals (Sweden)

Zhen Ding

2018-06-01

Full Text Available The traditional classification methods for limb motion recognition based on sEMG have been deeply researched and shown promising results. However, information loss during feature extraction reduces the recognition accuracy. To obtain higher accuracy, the deep learning method was introduced. In this paper, we propose a parallel multiple-scale convolution architecture. Compared with the state-of-art methods, the proposed architecture fully considers the characteristics of the sEMG signal. Larger sizes of kernel filter than commonly used in other CNN-based hand recognition methods are adopted. Meanwhile, the characteristics of the sEMG signal, that is, muscle independence, is considered when designing the architecture. All the classification methods were evaluated on the NinaPro database. The results show that the proposed architecture has the highest recognition accuracy. Furthermore, the results indicate that parallel multiple-scale convolution architecture with larger size of kernel filter and considering muscle independence can significantly increase the classification accuracy.

Changes in muscle activation patterns in response to enhanced sensory input during treadmill stepping in infants born with myelomeningocele

OpenAIRE

Pantall, Annette; Teulier, Caroline; Ulrich, Beverly D.

2012-01-01

Infants with myelomeningocele (MMC) increase step frequency in response to modifications to the treadmill surface. The aim was to investigate how these modifications impacted the electromyographic (EMG) patterns. We analyzed EMG from 19 infants aged 2–10 months, with MMC at the lumbosacral level. We supported infants upright on the treadmill for 12 trials, each 30 seconds long. Modifications included visual flow, unloading, weights, Velcro and lcriction. Surface electrodes recorded EMG from t...

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

Directory of Open Access Journals (Sweden)

Roberto Censolo

Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

Central motor control failure in fibromyalgia: a surface electromyography study.

Science.gov (United States)

Casale, Roberto; Sarzi-Puttini, Piercarlo; Atzeni, Fabiola; Gazzoni, Marco; Buskila, Dan; Rainoldi, Alberto

2009-07-01

Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin. Eight female patients aged 55.6 +/- 13.6 years (FM group) and eight healthy female volunteers aged 50.3 +/- 9.3 years (MCG) were studied by means of non-invasive surface electromyography (s-EMG) involving a linear array of 16 electrodes placed on the skin overlying the biceps brachii muscle, with muscle fatigue being evoked by means of voluntary and involuntary (electrically elicited) contractions. Maximal voluntary contractions (MVCs), motor unit action potential conduction velocity distributions (mean +/- SD and skewness), and the mean power frequency of the spectrum (MNF) were estimated in order to assess whether there were any significant differences between the two groups and contraction types. The motor pattern of recruitment during voluntary contractions was altered in the FM patients, who also showed fewer myoelectrical manifestations of fatigue (normalised conduction velocity rate of changes: -0.074 +/- 0.052%/s in FM vs -0.196 +/- 0.133%/s in MCG; normalised MNF rate of changes: -0.29 +/- 0.16%/s in FM vs -0.66 +/- 0.34%/s in MCG). Mean conduction velocity distribution and skewnesses values were higher (p fatigue in FM is the electrophysiological expression of muscle remodelling in terms of the prevalence of slow conducting fatigue-resistant type I fibres. As the only between-group differences concerned voluntary contractions, they are probably more related to central motor control failure than muscle membrane alterations, which suggests pathological muscle fibre remodelling related to altered suprasegmental control.

The defence technique in Tai Chi Push Hands: a case study.

Science.gov (United States)

Chen, Hui-Chuan; Cheng, Kuang-You B; Liu, Yu-Jen; Chiu, Hung-Ta; Cheng, Kuang-Yu

2010-12-01

Developed from traditional Chinese martial arts, Tai Chi exercise includes different forms and interactive Push Hands but biomechanical analyses have focused on the former only. To analyse the techniques of Push Hands, an experienced master was asked to defend pushing by four opponents. Movements were videotaped and digitized using a motion analysis system. Surface electrodes were used to record the electromyographic activity of ten muscle groups. Two force plates were used to measure the ground reaction force on each foot. Inexperienced individuals performed the same procedure to serve as the control group. The results indicate that the master adopted a postural adjustment to maintain balance. A clear shift of body weight from the front to the rear foot and mediolateral displacement of the centre of gravity was observed. Low electromyographic activity was observed in the upper body muscle groups, while high electromyographic activity was observed in the right rectus femoris and very high activity in the left rectus femoris during the defence. All inexperienced participants lost their balance in resisting pushing. It is concluded that the Tai Chi defensive technique includes a subtle postural adjustment that slightly changes the pushing force direction, and allows the rear leg to resist the incoming force.

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.