Search Results
Results 201 - 250 of 681
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Borg Frank - - 2007
In an experiment, we combined force plate measurements and surface EMG in studying quiet and perturbed standing, involving MS (Multiple sclerosis) and controls. The aim of this paper is to report the results thus obtained on the relation between filtered gastrocnemius (GA) EMG and the anterior-posterior center-of-pressure (A/P COP) coordinate. ...
Cescon Corrado - - 2007
In order to better understand the mechanisms of generation of mechanomyography (MMG) signals, the two-dimensional distribution of surface MMG produced by the activity of single motor units was analyzed by a novel two-dimensional recording method. Motor unit action potentials were identified from intramuscular electromyographic (EMG) signals and used to trigger ...
Kumar Shrawan - - 2006
BACKGROUND: Back injury is a common place in our society. Up to two-thirds of back injuries have been associated with trunk rotation. However, the torque production ability with a rotated spine and electromyographic activity of trunk muscles in such efforts is poorly understood. Therefore, the objectives of this study are ...
Schillings M L - - 2006
Physiological fatigue, a loss of maximal force producing capacity, may originate both from changes at the peripheral and at the central level. The readiness potential (RP) provides a measure to study adaptations to physiological fatigue at the motor cortex. We have studied the RP in the course of repetitive contractions ...
Klein Breteler Mary D - - 2007
Recent studies have described muscle synergies as overlapping, multimuscle groups defined by synchronous covariation in activation intensity. A different approach regards a synergy as a fixed temporal sequence of bursts of activity across groups of motoneurons. To pursue this latter definition, the present study used a principal component (PC) analysis ...
Ren Xiaomei - - 2006
We have developed an effective technique for extracting and classifying motor unit action potentials (MUAPs) for electromyography (EMG) signal decomposition. This technique is based on single-channel and short perioda9s real recordings from normal subjects and artificially generated recordings. This EMG signal decomposition technique has several distinctive characteristics compared with the ...
MacIsaac Dawn T - - 2006
A novel approach to muscle fatigue assessment is proposed. A function is used to map multiple myoelectric parameters representing segments of myoelectric data to a fatigue estimate for that segment. An artificial neural network is used to tune the mapping function and time-domain features are used as inputs. Two fatigue ...
Rasheed Sarbast - - 2006
An adaptive certainty-based supervised classification approach for electromyographic (EMG) signal decomposition is presented and evaluated. Similarity criterion used for grouping motor unit potentials (MUPs) is based on a combination of MUP shapes and two modes of use of motor unit (MU) firing pattern information: passive and active. Performance of the ...
Klein C S - - 2006
Human muscles paralysed chronically by spinal cord injury (SCI) fatigue excessively. Whether these reductions in force reflect a decrease in the fatigue resistance of the motor units is unknown. Our aim was to determine the fatigability of thenar motor units paralysed chronically (10 +/- 2 years) by cervical SCI. Surface ...
Malek Moh H - - 2006
The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean power frequency (MPF) versus power output relationships during incremental cycle ...
Johanson M Elise - - 2006
Contamination of electromyographic (EMG) data due to crosstalk in recordings from surface electrodes can lead to misinterpretation of results. The purpose of this study was to determine if removing a portion of the EMG signal normalized to a maximum voluntary contraction (MVC) would improve the specificity of surface electrode recordings. ...
Sanderson David J - - 2006
Several authors have shown different excitation patterns for soleus and gastrocnemius muscles in response to cadence manipulation during cycling. The purpose of this study was to examine gastrocnemius and soleus length and velocity change as a function of pedalling cadence to consider mechanisms underlying these excitation differences. Ten male and ...
Kitamura Toru T Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto, Tokyo. - - 2006
The purpose of this research is to construct an intelligent upper limb prosthesis control system that uses electromyogram (EMG) signals. The signal processing of EMG signals is performed using a linear multiple regression model that can learn parameters in a short time. Using this model, joint angles are predicted, and ...
McKeown M J - - 2006
OBJECTIVES: To determine if novel methods establishing patterns in EEG-EMG coupling can infer subcortical influences on the motor cortex, and the relationship between these subcortical rhythms and bradykinesia. BACKGROUND: Previous work has suggested that bradykinesia may be a result of inappropriate oscillatory drive to the muscles. Typically, the signal processing ...
Lu Jianyin J Cell/Biodynamics Simulation Project, Kyoto Univ., Kyoto, Japan. - - 2006
The efficiency of heart pump function greatly depends on synchronized contraction of myocardial muscle. In this work, contraction simulation of an excitable ventricular tissue cable was constructed to study the influence of excitation patterns on tissue contraction. The tissue cable is composed of elements which contract when excited by an ...
Baldissera Fausto G - - 2006
BACKGROUND: Synchrony of coupled oscillations of ipsilateral hand and foot may be achieved by controlling the interlimb phase difference through a crossed kinaesthetic feedback between the two limbs, or by an independent linkage of each limb cycle to a common clock signal. These alternative models may be experimentally challenged by ...
Thomas C K - - 2006
Few studies have analyzed activity-induced changes in EMG activity in individual human motor units. We studied the changes in human thenar motor unit EMG that accompany the potentiation of twitch force and fatigue of tetanic force. Single motor unit EMG and force were recorded in healthy subjects in response to ...
Stylianou Antonis P - - 2005
Innovative applications of non-linear time series analysis have recently been used to investigate physiological phenomena. In this study, we investigated the feasibility of using the correlation integral to monitor the localized muscle fatigue process in the biceps brachii during sustained maximal efforts. The subjects performed isometric maximum contractions until failure ...
Blok Joleen H - - 2005
High-density multichannel electromyography (EMG) recordings add spatial information to the temporal information content of the surface EMG (sEMG) signal. This study explores the potential value of such multichannel information at a single motor unit level, in particular for the improvement of motor unit number estimation (MUNE) techniques. It is shown ...
Gillespie James I - - 2005
Although caution should be used when applying animal data to human physiology, if care is taken to differentiate between general principles and complications of detail, particular to the species being examined, then experimentation on animal models can reveal basic phenomena in the bladder that offer clues to the origin of ...
Drake Janessa D M - - 2006
Trunk electromyographic signals (EMG) are often contaminated with heart muscle electrical activity (ECG) due to the proximity of the collection sites to the heart and the volume conduction characteristics of the ECG through the torso. Few studies have quantified ECG removal techniques relative to an uncontaminated EMG signal (gold standard ...
Malek Moh H - - 2006
The purpose of this study was to examine the effects of interelectrode distance (IED) on the relationships of absolute and normalized EMG amplitude and mean power frequency (MPF) versus power output during incremental cycle ergometry. Eleven adults (mean +/- S.D. age = 24.2 +/- 2.6 y; V(O2max) = 49.4 +/- ...
Cescon Corrado - - 2006
The aim of the study was to investigate amplitude and frequency content of single motor unit (MU) electromyographic (EMG) and mechanomyographic (MMG) responses. Multi-channel surface EMG and MMG signals were detected from the dominant biceps brachii muscle of 10 volunteers during isometric voluntary contractions at 20%, 50%, and 80% of ...
Hernández Ivonne A - - 2006
The objectives of this study were to evaluate behavior of sternocleidomastoid muscle (SCM) electromyogram (EMG) related to impact velocity, gender, awareness and kinematics of head movement in simulated low velocity rear-end impacts. Twenty-nine healthy adults (17 male) were subjected in random order to three rear-end impacts: Two unexpected impacts causing ...
Nam K C - - 2005
AIM: To measure excessive electrical stimulus time during pulp testing via electromyography (EMG) in the anterior belly of the digastric muscle, voice and finger movement, and to determine whether excessive stimulus time could be attenuated by a specially designed automatic circuit breaker on the basis of the EMG signal. METHODOLOGY: ...
Avedisian Lori - - 2005
Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal ...
Blackburn J Troy - - 2006
The spinal stretch reflex (SSR) is commonly assessed via electromyographic (EMG) analysis of joint perturbations inducing changes in muscle length. Previous literature indicates that when large experimental changes in magnitude of agonist background EMG, perturbation velocity, and perturbation amplitude are employed, SSR latency and amplitude are significantly altered. The purpose ...
Beck Travis W - - 2006
The purpose of this study was to compare the eccentric torque-related patterns for mechanomyographic (MMG) center frequencies (mean power frequency (MPF), median frequency (MDF), and average instantaneous mean power frequency (AIMPF)) determined by the fast Fourier transform (FFT) and continuous wavelet transform (CWT). Eight adults (mean+/-S.D. age=22.5+/-2.4 years) performed submaximal ...
Jiang Zongliang - - 2005
Lifting in most industrial environments is performed on a smooth, level ground surface. There are, however, many outdoor work environments (e.g. agriculture and construction) that require manual material handling activities on variable grade ground surfaces. Quantifying the biomechanical response while lifting under these conditions may provide insight into the aetiology ...
Gerritsen R - - 2005
This study aims to examine influences of specific boar stimuli on uterine activity in estrous sows, by comparing uterine activity in presence of a mature teaser boar and a robot boar with variable stimuli. Nineteen multiparous, cyclic, commercial crossbred sows were used. Intra-luminal uterine pressure was measured using a non-surgical ...
Durkin Jennifer L - - 2005
Signal oversampling is frequently used to prevent distortion in time-series representations. When sampling at rates just above the Nyquist critical frequency (f(c)), Shannon's reconstruction theorem provides an alternative means of circumventing this problem. The purpose of this study was to determine whether surface electromyographic (EMG) data is compromised when sampled ...
Robichaud Julie A - - 2005
Several measures of isometric contractions reflect motor impairments in subjects with Parkinson's disease (PD), including long relaxation times and greater power in the 5 to 15 Hz electromyographic (EMG) bandwidth during the holding phase of contractions compared to those measures in healthy subjects. We sought to determine whether the impairments ...
Sosnoff Jacob J - - 2005
The purpose of this study was to examine the modulation of the motor neuronal pool as a function of task dynamics. Specifically, we investigated the effects of task frequency on the single motor unit discharge pattern, electromyogram (EMG) activity and effector force output. Myoelectric activity and effector force were recorded ...
Ochala Julien - - 2005
The present study deals with the question whether 24-week strength training alters neuromechanical properties of plantar flexors in elderly people (73-83 years). The first purpose of the present study was to evaluate the effect of strength training on musculotendinous (MT) stiffness of the triceps surae (TS). The training was performed ...
Mazzaro Nazarena - - 2005
The aim of this study was to investigate the contribution of feedback from large-diameter sensory fibers to the adaptation of soleus muscle activity after small ankle trajectory modifications during human walking. Small-amplitude and slow-velocity ankle dorsiflexion enhancements and reductions were applied during the stance phase of the gait cycle to ...
Akazawa Jun J Nara Institute of Science and Technology, Ikoma, Nara, 630-0192 Japan - - 2005
Surface motor unit action potential (SMUAP) is generated from a motor unit (MU) located at certain depth from the skin surface. The depth is referred to as MU location in the present papers. The MU location affects the amplitude of MUAP, and smoothed rectified electromyogram (SR EMG) is used to ...
Ricard M D - - 2005
The purpose of this study was to compare the amplitude and frequency of the gastrocnemius EMG during ramp and ballistic contractions in highly trained sprint athletes. Sixteen female sprinters performed ramp and ballistic isometric contractions on a Biodex dynamometer. RMS and median frequency of the gastrocnemius EMG signals were obtained ...
Lee Jongho - - 2005
In this paper, we propose a method to extract motor primitives from electromyography(EMG) signals on reaching movements of human arm. EMG signals reflect the motor commands from the central nervous system(CNS). Especially, we extract the motor primitives in consideration of arm posture, movement direction and velocity using only EMG signals. ...
Jiang M M Division of Intelligent and Biomechanical System, State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, - - 2005
In this paper, an identification method of finger motions using the wavelet transform of multi-channel electromyography (EMG) signal is presented. The first step of this method is to analyze surface EMG signal detected from the subject's upper arm using the multi-resolution of wavelet transform, and extract features using the variance, ...
Ramon Ceon - - 2005
Our objective was to quantify and compare the extent of synchronization of the spatial-temporal myometrial activity over the human uterus before and during a contraction using transabdominal magnetomyographic (MMG) recordings. Synchronization can be an important indicator for the quantification of uterine contractions. The spatialtermporal myometrial activity recordings were performed using ...
Ricamato Anthony L - - 2005
A technique for analyzing and comparing the dynamic properties of electromyographic (EMG) patterns collected during gait is presented. A gait metric is computed, consisting of both magnitude (amplitude) and phase (timing) components. For the magnitude component, the processed EMG pattern is compared to a normative EMG pattern obtained under similar ...
Clancy Edward A - - 2005
Various conventional methods to estimate the mean and median power spectral frequencies, and amplitude of the surface electromyogram during 30-90 min, cyclic, force-varying, constant-posture contractions were cross-compared in an experimental trial. The aim was to determine the most appropriate algorithm implementations and reduce the total number of algorithms that need ...
Akataki K - - 2004
Electromyographic and mechanomyographic estimation of motor unit activation strategy in voluntary force production. In order to determine whether electromyogram (EMG) and mechanomyogram (MMG) are suitable for the noninvasive estimation of the motor unit (MU) activation strategy, the EMG/force and MMG/force relationships were examined simultaneously during isometric ramp contractions in biceps ...
Ravier Philippe - - 2005
During a sustained contraction, electromyographic signals (EMGs) undergo a spectral compression. This fatigue behaviour induces a shift of the mean and the median frequencies to lower frequencies. On the other hand, several studies conclude that the mean/median frequency can increase, decrease or remain constant with an increasing force level. Such ...
Fattorini L - - 2005
The aim of this study was to investigate the influence of high degrees of motor unit synchronization on surface EMG variables extracted by linear and non-linear analysis techniques. For this purpose, spectral and recurrent quantification analysis (RQA) were applied to both simulated and experimental EMG signals. Synthetic surface EMG signals ...
Brinkworth Russell S A RS Research Centre for Human Movement Control, Discipline of Physiology, School of Molecular and Biomedical Science, The University of Adelaide, 5005, Adelaide, South Australia, - - 2005
Reflex studies utilising controlled stimulation along the long axis of human incisors are relatively new, and the effects that various stimulus parameters have on the elicited reflexes are not fully understood. Twelve subjects were recruited to determine the effects that contraction level, stimulus force and amount of constant force applied ...
Wang Shou-Yan - - 2004
The compound surface electromyograms (EMGs) recorded from patients with dystonia commonly contains superimposed bursting and tonic activity representing various motor symptoms. It is desirable to differentially extract them from the compound EMGs so that different symptoms can be more specifically investigated and different mechanisms revealed. A non-linear denoising approach based ...
Yahagi Susumu S Division of Sports and Health Sciences, Graduate School for International Development and Cooperation, Hiroshima University, 1717 Ohtsuka, Numata-cho, Asaminami-ku, Hiroshima, - - 2005
The goal of this study was to investigate how corticospinal tract neurons (CTNs) are modulated after repetitive dynamic muscle contractions. To address this question, changes of motor evoked potentials (MEPs) to transcranial magnetic stimulation and background EMG (B.EMG) activities were examined. Subjects were instructed to perform an isometric dynamic index ...
Skotte J H - - 2004
The purpose of this study was to investigate short-term changes in reactions to sudden unexpected loading of the low back. The study utilized a set-up where a horizontal force of 58 N pointing forward suddenly was applied to the upper part of the subject's trunk. EMG activity from the erector ...
Pelland Lucie - - 2004
The purpose of this research was to develop and test an analytical tool that would recognize and classify the surface electromyographic (EMG) signal of co-activating muscles of the leg into pre-defined patterns of muscle activity: burst, tonic, and tonic-burst. Developed to study the task of landing from a jump in ...
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