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Cote Julie N - - 2008
Fatigue affects the capacity of muscles to generate forces and is associated with characteristic changes in EMG signals. It may also influence interjoint and intermuscular coordination. To understand better the global effects of fatigue on multijoint movement, we studied movement kinematics and EMG changes in healthy volunteers asked to hammer ...
Keenan Kevin G - - 2008
Researchers and clinicians routinely rely on interference electromyograms (EMGs) to estimate muscle forces and command signals in the neuromuscular system (e.g., amplitude, timing, and frequency content). The amplitude cancellation intrinsic to interference EMG, however, raises important questions about how to optimize these estimates. For example, what should the length of ...
Muthuraman M - - 2008
OBJECTIVE: Differentiating between a fixed activation pattern (phase shift) and conduction time (time delay) in rhythmic signals has important physiological implications but is methodologically difficult. METHODS: Delay was estimated by the maximising coherence method and phase spectra calculated between (i) a narrow band-pass filtered AR2 process and its delayed copy ...
Masakado Yoshihisa - - 2008
Cortico-muscular coherence was compared during ramp-and-hold isometric and quasi-isotonic contraction of the ankle joint in human subjects. EEG was recorded from the leg area of the motor cortex. EMG was recorded from the tibialis anterior (TA) muscle. The subjects were requested to maintain a steady low level of dorsiflexion and ...
van Swigchem R - - 2009
Although the practice of fall techniques has been introduced in fall prevention programs, it is not clear whether people can apply acquired techniques during a real-life fall. It would be helpful to know the time it takes to initiate and to successfully execute such techniques, as well as the effect ...
BariƟçi Necaattin - - 2008
In this study, Adaptive auto regressive-moving average (A-ARMA) analysis of EMG signals recorded on the ulnar nerve region of the right hand in resting position was performed. A-ARMA method, especially in the calculation of the spectrums of stationary signals, is used for frequency analysis of signals, which give frequency response ...
Pitcher Mark J - - 2008
Maximal voluntary isometric activations (MVIA) are frequently used as inputs for models attempting to predict muscle force and as normalization values in studies assessing muscle function. However, pain may adversely affect maximal muscle activation. The purpose of this study was to assess reliability of MVIA force and electromyographic (EMG) activity ...
Winges Sara A - - 2008
Rotation of an object held with three fingers is produced by modulation of force amplitude and direction at one or more contact points. Changes in the moment arm through which these forces act can also contribute to the modulation of the rotational moment. Therefore force amplitude and direction as well ...
Schwartz Fabiano P FP Department of Electrical Engineering, University of Brasília, DF 70910-900 Brazil. - - 2008
Spatial filtering has become a common way to improve the resolution of surface electromyographic signals (SEMG) when used in connection with electrode arrays. The goal of this study is to observe the behavior of S-EMG amplitude and spectral descriptors when signals are submitted to a longitudinal quadruple differentiating spatial filter. ...
Lin Jenq-Dong - - 2008
The purpose of this study was to investigate the effects of different stretch amplitudes (angular displacements) on the performance and electromyographic (EMG) activity during drop jumps (DJs). The AMTI force platform, the Biovision electrical goniometer, and EMG system were used to record the ground reaction forces, knee angular displacement, and ...
Witte Matthias - - 2007
Although corticomuscular synchronization in the beta range (15-30 Hz) was shown to occur during weak steady-state contractions, an examination of low-level forces around 10% of the maximum voluntary contraction (MVC) is still missing. We addressed this question by investigating coherence between electroencephalogram (EEG) and electromyogram (EMG) as well as cortical ...
Grönlund C - - 2009
Motor unit (MU) synchronization is the result of commonality in the pre-synaptic input to MUs. Previously proposed techniques to estimate MU synchronization based on invasive and surface electromyography (sEMG) recordings have been, respectively, limited by the analyzed MU population size and influence of changes in muscle fibre conduction velocities (MFCVs). ...
Wakeling James M - - 2009
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 ...
Liang Nan - - 2008
Although many studies have examined performance improvements of ballistic movement through practice, it is still unclear how performance advances while maintaining maximum velocity, and how the accompanying triphasic electromyographic (EMG) activity is modified. The present study focused on the changes in triphasic EMG activity, i.e., the first agonist burst (AG1), ...
Preece Stephen J - - 2008
There is a common clinical belief that transverse plane tibial rotation is controlled by the rearfoot. Although distal structures may influence the motion of the tibia, transverse plane tibial rotation could be determined by the proximal hip musculature. Cadaver studies have identified gluteus maximus as having the largest capacity for ...
Tella V - - 2008
The present study analyzes the changes in acceleration produced by swimmers before and after fatiguing effort. The subjects (n = 15) performed a 25-m crawl series at maximum speed without fatigue, and a second series with fatigue. The data were registered with a synchronized system that consisted of a position ...
Mitchell W Kyle - - 2007
Muscle responses to transcranial stimulation show high sweep-to-sweep variability, which may reflect an underlying noise process in the motor system. We examined whether response amplitude correlated with the level of prestimulus background EMG, and network oscillations. Transcranial magnetic or electrical stimulation was delivered to primary motor cortex whilst human subjects ...
Lepora N F - - 2007
Classical conditioning of nictitating membrane (NM) responses in rabbits is a robust model learning system, and experimental evidence indicates that conditioned responses (CRs) are controlled by the cerebellum. It is unknown whether cerebellar control signals deal directly with the complex nonlinearities of the plant (blink-related muscles and peripheral tissues) or ...
Kaplanis P A - - 2009
The objective of this study was to compute reference SEMG values for normal subjects of 13 parameters extracted in the time, frequency and bispectrum domain, from the Biceps Brachii (BB) muscle generated under isometric voluntary contraction (IVC). SEMG signals were recorded from 94 subjects for 5s at 10, 30, 50, ...
Zhou Ping - - 2007
The sensitivity of the electromyogram (EMG)-force relation to changes in motoneuron and muscle properties was explored using a simulation approach, and by applying existing motoneuron pool, muscle force, and surface EMG models. The simulation results indicate that several factors contribute potently to known changes in the EMG-force relation in paretic ...
Falla Deborah D Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, D-3, 9220 Aalborg, Denmark. - - 2007
This study compared fatigue and the spatial distribution of upper trapezius electromyographic (EMG) amplitude during a 6-min constant force shoulder elevation task at 20% of the maximal voluntary contraction force (MVC) (constant force) and during the same task interrupted by brief (2 s) periodic increases in force to 25% MVC ...
Shan Gongbing - - 2008
Bike power saver (BPS) is a new product that claims to change the angle of pedaling forces and reduce applied power dead range (Chic Sheng Industrial Co., Ltd, Taiwan, China). In order to determine its effectiveness, we quantified how BPS operates through a 3D kinematical study and electromyography (EMG) analysis ...
Hargrove Levi J - - 2007
The surface myoelectric signal (MES) has been used as an input to controllers for powered prostheses for many years. As a result of recent technological advances it is reasonable to assume that there will soon be implantable myoelectric sensors which will enable the internal MES to be used as input ...
Jones T - - 2007
The primary objectives of the study were to 1) describe the physical exposures in a sawmill job with a high incidence of upper extremity musculoskeletal injuries in terms of multiple measures of posture, exertion and frequency (with varying definitions) and 2) to examine the comparability of those definitions. Surface electromyography ...
Boisnoir A - - 2007
Biomechanical analyses using synchronized tools [electromyography (EMG), motion capture, force sensors, force platform, and digital camera] are classically performed in a laboratory environment that could influence the performance. We present a system for studying the running sprint start that synchronizes motion capture, EMG, and ground reaction force data. To maximize ...
Raikova Rositsa - - 2007
In the present study a previously proposed model of a twitch based on an analytical function with four-parameters (lead, contraction and half-relaxation times and maximum force of the twitch) was validated on 115 motor units (MUs), divided into slow (S), fast-fatigue resistant (FR) and fast fatigable (FF) types. The original ...
Clancy Edward A - - 2008
The amplitude and mean power spectral frequency (MNF) of the electromyogram (EMG) of flexor digitorum superficialis and extensor carpi radialis muscles were monitored during cyclic, force-varying, constant-posture, submaximal, grip-force contractions until endurance. These contractions are reminiscent of work tasks associated with the risk of repetitive stress injuries. Based on recommendations ...
Raikova R - - 2008
Stimulation of motor units (MUs) with repeated pulses evokes tetanic contractions, which consist of overlapping mechanical responses. The summation of these responses into tetanus is a nonlinear process due to the dynamic changes in the amplitudes and time parameters of the successive components. In order to study these changes, two ...
Oczeretko Edward - - 2007
The analysis of the uterine contraction signals in nonpregnant states gives information about physiological changes during the menstrual cycle. Spontaneous uterine activity was recorded directly by a dual microtip catheter. The device consisted of two ultra-miniature pressure sensors. One sensor was placed in the fundus, the other in the cervix. ...
Mobasser Farid - - 2007
In many studies and applications that include direct human involvement-such as human-robot interaction, control of prosthetic arms, and human factor studies-hand force is needed for monitoring or control purposes. The use of inexpensive and easily portable active electromyogram (EMG) electrodes and position sensors would be advantageous in these applications compared ...
Morrison S S School of Physiotherapy and Exercise Science, Gold Coast Campus Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, QLD, 9726, Australia. - - 2007
The aim of this study was to investigate the postural center of pressure (COP) and surface muscle (EMG) dynamics of young adult participants under conditions where they were required to voluntarily produce random and regular sway motions in contrast to that of standing still. Frequency, amplitude and regularity measures of ...
Defilippi Carlos - - 2007
During continuous intraintestinal infusion of elementary diets, periodic fluctuation of the frequency of contractions has been observed. This study sought to characterize the temporospatial organization of this pattern and the influence of cholinergic input. Studies were performed on unanesthetized dogs with a duodenal cannula. Motor activity was recorded by means ...
Bosch T - - 2007
Optimization of the temporal aspects of task design requires a better understanding of the development of muscle fatigue in the neck and shoulder region over time. The objective of the study was to investigate this in two production companies and to determine the relationship between objective and subjective estimates of ...
Descarreaux Martin - - 2007
OBJECTIVE: This study correlates changes in trunk isometric force parameters and trunk muscle recruitment strategies in subjects with low back pain (LBP) and healthy participants. METHODS: A control group study with repeated measures was performed. Study participants included 15 control subjects and 14 patients with LBP. Participants were required to ...
Tenore Francesco F Department of Electrical & Computer Engineering, The Johns Hopkins University, Baltimore, MD, - - 2007
The fast pace of development of upper-limb prostheses requires a paradigm shift in EMG-based controls. Traditional control schemes are only capable of providing 2 degrees of freedom, which is insufficient for dexterous control of individual fingers. We present a framework where myoelectric signals from natural hand and finger movements can ...
Khezri Mahdi - - 2007
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 ...
Piotrkiewicz Maria - - 2007
Tetanic potentiation is a phenomenon, which expresses the ability of a motor unit (MU) to increase its force output in tetanic contractions above that predicted with an assumption of algebraic summation of single twitch responses. To quantify tetanic potentiation, a coefficient TPC (tetanic potentiation coefficient) was defined as a ratio ...
Kiguchi Kazuo K Department of Advanced Systems Control Engineering, Saga University, Saga-shi, Saga 840-8502, Japan. - - 2007
We have been developing a 4DOF exoskeleton robot system in order to assist shoulder vertical motion, shoulder horizontal motion, elbow motion, and forearm motion of physically weak persons such as elderly, injured, or disabled persons. The robot is directly attached to a user's body and activated based on EMG (Electromyogram) ...
Khezri Mahdi M Department of Electrical Engineering, Sharif University of Technology, Biomedical Engineering and Robotic Laboratories, Tehran, Iran. - - 2007
Electromyogram signal (EMG) is an electrical manifestation of contractions of muscles. Surface EMG (sEMG) signal collected form surface of the skin has been used in diverse applications. One of its usages is exploiting it in a pattern recognition system which evaluates and synthesizes hand prosthesis movements. The ability of current ...
Hodges P W - - 2007
AIMS: Due to their contribution to modulation of intra-abdominal pressure (IAP) and stiffness of the sacroiliac joints, the pelvic floor muscles (PFM) have been argued to provide a contribution to control of the lumbar spine and pelvis. Furthermore, as IAP is modulated during respiration this is likely to be accompanied ...
Zhang Dingguo D School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore. - - 2007
A novel assistive system is designed to suppress pathological tremor of forearm via functional electrical stimulation (FES). It aims to attenuate the tremor with the minimum effect on the voluntary movement. Surface electromyograph (EMG) is adopted as the sensing feedback information to regulate FES. A two-stage filter is proposed to ...
Cheron Guy - - 2007
Triphasic electromyographic (EMG) patterns with a sequence of activity in agonist (AG1), antagonist (ANT) and again in agonist (AG2) muscles are characteristic of ballistic movements. They have been studied in terms of rectangular pulse-width or pulse-height modulation. In order to take into account the complexity of the EMG signal within ...
Calder Kristina M - - 2008
The purpose of this study was to determine (i) if decomposition-based quantitative electromyography (DQEMG) could detect changes in motor unit potential (MUP) morphology and motor unit (MU) firing pattern statistics associated with muscle fatigue, (ii) if any detected changes are correlated with surface electromyographic (SEMG) signs of fatigue, and (iii) ...
Ryan Eric D - - 2008
The purposes of this study were to examine the mechanomyographic (MMG) and electromyographic (EMG) time and frequency domain responses of the vastus lateralis (VL) and rectus femoris (RF) muscles during isometric ramp contractions and compare the time-frequency of the MMG and EMG signals generated by the short-time Fourier transform (STFT) ...
Chen Wei-ting - - 2006
An improved approximate entropy (ApEn) is presented and applied to characterize surface electromyography (sEMG) signals. In most previous experiments using nonlinear dynamic analysis, this certain processing was often confronted with the problem of insufficient data points and noisy circumstances, which led to unsatisfactory results. Compared with fractal dimension as well ...
Belavý D L - - 2006
The timing of muscle activity is commonly measured in studies of motor control. In repetitive-movement tasks, muscle activity may be continuous, and no defined onset or offset of activity may be measured. This does not imply that no timing of muscle activity occurs. Where activity is continuous, this timing will ...
Mendoza Julianne - - 2006
BACKGROUND: The application of longitudinal mechanical force induces lengthening of the small intestine. The purpose of this study is to evaluate the contractile function of the mechanically lengthened jejunum in a rodent model. MATERIALS AND METHODS: Three groups of rats including normal jejunum, isolated jejunal segment without mechanical lengthening, and ...
Dimitrov G V - - 2008
Capabilities of amplitude and spectral methods for information extraction from interference EMG signals were assessed through simulation and preliminary experiment. Muscle was composed of 4 types of motor units (MUs). Different hypotheses on changes in firing frequency of individual MUs, intracellular action potential (IAP) and muscle fibre propagation velocity (MFPV) ...
Dimitrov G V - - 2008
Decline in amplitude of EMG signals and in the rate of counts of intramuscularly recorded spikes during fatigue is often attributed to a progressive reduction of the neural drive only. As a rule, alterations in intracellular action potential (IAP) are not taken into account. To test correctness of the hypothesis, ...
Madeleine Pascal - - 2006
The purpose of this laboratory study was to investigate the effects of surface electromyography (EMG)- and mechanomyography (MMG)-based audio and visual biofeedback during computer work. Standardized computer work was performed for 3 min with/without time constraint and biofeedback in a randomized order. Biofeedback was given on the basis of an ...
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