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Results 301 - 350 of 681
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Vaillancourt David E - - 2003
The purpose of this investigation was to examine the discharge properties of single motor units and the structure of the rectified 10, 20, and 40 Hz electromyographic (EMG) activity to determine a physiological correlate for the greater force variability with aging. Young (n=10; mean: 22+/-1 years), old (n=10; mean: 67+/-2 ...
Kumar Shrawan - - 2003
BACKGROUND CONTEXT: Trunk rotation is associated with over 60% of all low back injuries. However, there are gaps in the knowledge about trunk rotation. PURPOSE: To study the axial rotation torque and electromyographs (EMGs) of seven trunk muscles bilaterally in static and isokinetic modes with increasing angular velocity to determine ...
Claudon Laurent - - 2003
The aim of the present study was to develop a relationship to evaluate grip force using the electromyogram (EMG) in isometric anisotonic conditions. The EMGs of the flexor digitorum superficialis (FDS) and the extensor digitorum (ED) were recorded in 3 flexion-extension positions of the wrist (30 degrees flexion, 30 degrees ...
Manto M U - - 2002
Spatial tuning of goal-directed movements is a critical phenomenon for the central nervous system. The use of reliable models is a necessary step for the understanding of the neural mechanisms governing reaching movements. We analysed phasic electromyographic (EMG) activities associated with upper limb reaching movements in the vertical plane (12 ...
Semmler John G - - 2002
This study examined the strength of motor unit synchronisation based on time- and frequency-domain measures during postural, shortening and lengthening contractions of a hand muscle in young adults. Single motor unit activity was recorded with intramuscular electrodes in the left first dorsal interosseus muscle as the subject held the index ...
von Tscharner Vinzenz - - 2002
Electromyographic signals contain the information on muscle activity and have to be frequently averaged, compared, classified or details need to be extracted. A time-frequency analysis, based on wavelets, was previously presented. The analysis transformed an EMG signal into an EMG-intensity-pattern showing the intensities at any point in time for the ...
Klein C S - - 2002
This study examined, in nine old men (82 +/- 4 yr), whether there is an association between the magnitude of change in motor unit discharge rate and the amount of twitch potentiation after a conditioning contraction (CC). The evoked twitch force and motor unit discharge rate during isometric ramp-and-hold contractions ...
Arnall Frances A - - 2002
OBJECTIVE: To ascertain which percentage of maximal voluntary contractile force of the paraspinal muscles, when tested in a functional position, is most reliable for assessing electromyographic (EMG) fatigue changes. SUBJECTS: Ten healthy volunteers with no history of low back pain (six males). MAIN OUTCOME MEASURES: The surface EMG signal during ...
Gabriel David A - - 2002
This paper examines changes in the variability of electromyographic (EMG) activity and kinematics as a result of practicing a maximal performance task. Eight subjects performed rapid elbow flexion to a target in the horizontal plane. Four hundred trials were distributed equally over four practice sessions. A potentiometer at the elbow ...
Fumoto Masaki - - 2002
The relationship between the size of the soleus (Sol) Hoffmann (H-) reflex and the level of background (BG) electromyographic (EMG) activity was examined during plantarflexing at different force levels. The experiments were carried out on seven healthy male subjects aged 20-37 years. The subjects were asked to perform fast plantarflexion ...
Bose Prodip - - 2002
Progressive neurophysiological changes in the excitability of the pathways that subserved ankle extensor stretch reflexes were observed following midthoracic contusion. The purpose of the present study was to determine the nature and time course of velocity-dependent changes in the excitability of the ankle stretch reflex following T(8) contusion injury. These ...
Moore Brian D - - 2002
We examined the effects of fatigue on patellar tendon reflex responses in males and females. A spring-loaded reflex hammer elicited a standardized tendon tap with the knee positioned in an isokinetic dynamometer and flexed to 85 degrees. We recorded vastus lateralis activity (SEMG) and knee extension force production at the ...
Rafolt D - - 2002
A moving magnet galvanometer equipped with lever and indentor was evaluated for mechanomyography (MMG). First, the precision of the galvanometer was tested on a piezo-electric disc actuator. Using a 50 mm lever, synthesised micromotions with an amplitude of 1 microm could be detected (noise level < 0.2 microm) at static ...
Danion Frédéric - - 2002
The goal of this experiment was to investigate the relationship between individual fingertip forces and the surface EMG of multi-digit muscles. The surface EMG of the hand extrinsic flexors (flexor digitorum profundis and superficialis) was recorded in eight subjects during multi-digit force production tasks. In one session, subjects pressed with ...
Hansen S S Division of Neurophysiology, Department of Medical Physiology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, - - 2002
In 35 healthy human subjects coupling of EMGs recorded from the tibialis anterior (TA) and soleus (Sol) muscles during voluntary co-contraction was analysed in the time and frequency domains. Two patterns were observed in different subjects or in the same subject on different occasions. One pattern consisted of central peaks ...
Ebenbichler Gerold R - - 2002
PURPOSE: To test the short-term and long-term reliability of time-frequency electromyographic (EMG) measures of fatigue during repetitive dynamic lifting and compare it with the reliability of median frequency (MF) EMG measures of fatigue during static lifting. METHODS: Fourteen' healthy male subjects (26 +/- 5 years) repetitively (12 lifts/min) lifted and ...
Elfving Britt - - 2002
In order to study the influence of interelectrode distance and force level on the electromyographic (EMG) spectral parameters and on their reliability, bipolar surface EMG measurements were performed on the lumbar muscles of 15 subjects. Two test contractions (45 s) at 40% of maximal voluntary contraction (MVC) were performed, one ...
Naito A - - 2002
Motions of the forearm induced by electrical stimulation to two elbow flexors (brachioradialis: BR, biceps brachii: BB) were examined in five healthy human subjects. Stainless steel wire electrodes were implanted percutaneously into each motor point of the muscles. The muscles were stimulated separately with a computer-controlled multi-channel stimulator. The motions ...
Dimitrova N A - - 2002
Besides the increased number of fibres, the reinnervated motor units (MUs) are characterised by an increased scattering the end-plates, greater desynchronization in the fibres' activation, greater dispersion in the diameters of the MU fibres and thus in propagation velocities along them. As a result, desynchronization in the moments, at which ...
Allison G T - - 2002
OBJECTIVE: To test the validity of high and low frequency band amplitudes of the surface electromyography (EMG) profile as representation of muscle fatigue. DESIGN: A within subjects (n=10) repeated measures design was used to collect surface EMG signals from the biceps during an isometric contraction under two levels of fatigue ...
Chi-Fishman Gloria - - 2002
Past videofluoroscopic and EMG evidence has shown that rapid sequential swallowing differs from discrete swallows, but our knowledge of the control strategies remains incomplete. This study examined in detail the interrelationships among kinematic variables to discern the strategies for deglutitive hyoid motion during discrete (5 cc, 10 cc, 20 cc, ...
Flanders Martha - - 2002
A wavelet analysis was developed to measure the timing of multiunit bursts in surface electromyograms (EMGs) from single trials. EMG data were taken from eleven elbow and/or shoulder muscles during reaching movements in six different directions, at a range of speeds. A relatively simple wavelet (db2) was chosen, and the ...
Berdah Stéphane V - - 2002
The aim of this human study was to objective cliaphragmatic electromyogram (EMG) changes after supraombilical laparotomy. The surface diapbragmatic FMG was recorded in patients (before and after laparotomy), and in healthy volunteers, during standardized inspiratory efforts sustained at -30 cmH2O (Muller manoeuvres). The quantitative EMG analysis showed significant postoperative modifications: ...
Eswaran H - - 2002
OBJECTIVE: The aim of this study was to explore the use of the wavelet transform technique to extract and display simultaneously the time, frequency and amplitude information corresponding to electromyographic (EMG) activity of the uterus during labor recorded using abdominal electrodes. METHODS: Uterine EMG signals were recorded from patients in ...
Gerard Michael J - - 2002
Two studies were conducted to determine the effects of enhanced auditory feedback on typing force, electromyography (EMG) and subjective discomfort. The introduction of enhanced auditory feedback caused a 10-20% reduction in 90th percentile typing force, finger flexor EMG, and finger extensor EMG. Adaptation to the enhanced auditory feedback occurred in ...
Keller Thierry - - 2002
Research groups in the field of functional electrical stimulation (FES) are often confronted with the fact that existing and commercially available FES stimulators do not provide sufficient flexibility and cannot be used to perform different FES tasks. The lack of flexibility of the commercial systems until now forced various FES ...
Van Schelven L J - - 2002
Quantitative analysis of myoelectric activity (EMG), to investigate small intestinal motility in rats, is normally based on manual classification into sequences of phase I, phase II and phase III. This classification is partly subjective. We aimed to develop a more objective method for the analysis of the migrating myoelectric complex ...
Ladegaard Jørn - - 2002
It all started in 1950 with the introduction of the first commercially available electromyography (EMG) system. From 1950 to 1973 was the era of the analog EMG systems: EMG signals were recorded, and subsequent analyses were carried out manually on film or paper. From 1973 to 1982, the first modular ...
Mamaghani Nasser Koleini - - 2002
To investigate the behavior of mechanomyogram (MMG) and electromyogram (EMG) signals in the time and frequency domains during sustained isometric contraction, MMG and surface EMG were obtained simultaneously from four muscles: upper trapezius (TP), anterior deltoid (DL), biceps brachii (BB), and brachioradialis (BR) of 10 healthy male subjects. Experimental conditions ...
Kinder M V - - 2001
Spontaneous bladder EMG was recorded in the living rabbit from an isovolumetric bladder without chemical or electrical stimulation. Mechanical intervention, either by lifting the bladder out of the abdomen or by rapid filling, resulted in stretch induced bladder EMG. A self made epoxy resin electrode device that embedded 32 EMG ...
Clancy E A - - 2001
The sections above have described an EMG amplitude estimator and an initial application of this estimator to the EMG-torque problem. The amplitude estimator consists of six stages. In the first stage, motion artifact and power-line interference are attenuated. Motion artifact is typically removed with a highpass filter. Elimination of power-line ...
Bichler E - - 2001
The aim of this study was to investigate mechanomyograms (MMGs) accompanying unfused tetani of fast fatigable (FF), fast fatigue-resistant (FR) and slow (S) motor units. Signals in the MMG were analyzed during tetanus, which was fused to a variable degree, evoked by electrical stimulation at three frequencies: 20, 40 and ...
Lauk M - - 2001
We investigated the electromyographic activity (EMG) of flexor and extensor muscles with different hand positions in patients with essential (ET) and parkinsonian (PD) tremor. Using a previously developed bootstrap method and standard cross-spectral analysis, we performed statistical tests to assess the effect of hand position on: (1) the frequency of ...
Axelson H W - - 2001
1. The primary aim of the present study was to explore whether in healthy subjects the muscle contractions required for unrestrained voluntary wrist dorsiflexions are adjusted in strength to thixotropy-dependent variations in the short-range stiffness encountered in measurements of passive torque resistance to imposed wrist dorsiflexions. 2. After a period ...
Gabriel D A - - 2001
PURPOSE: This paper investigates the neural mechanisms responsible for the increase in strength that occurs during serial isometric contractions. METHODS: A three-session design was used. Thirteen subjects (N = 13) were asked to perform five maximal isometric elbow extension strength trials to serve as baseline. After a 5-min rest, the ...
Perry S R - - 2001
The purpose of this investigation was to determine the relationships for mechanomyographic (MMG) amplitude, MMG mean power frequency (MPF), electromyographic (EMG) amplitude, and EMG MPF versus power output during incremental cycle ergometry. Seventeen adults volunteered to perform an incremental test to exhaustion on a cycle ergometer. The test began at ...
Solomonow M - - 2001
STUDY DESIGN: The reflexive EMG from the L3-L4 to L5-L6 multifidus of the in vivo feline was recorded during application of single passive flexion-extension cycle of the lumbar spine. OBJECTIVE: To determine the effect of viscoelastic hysteresis associated with a single-cycle flexion-extension and of increasing cycle frequency on the initiation ...
Anders C - - 2001
OBJECTIVE: To determine differences supposed in EMG parameters of the erector trunci region between patients with fibromyalgia and healthy subjects during defined investigation situations. METHODS: During sitting and standing in upright position surface EMG (SEMG) from 15 subjects with fibromyalgia and 10 healthy controls was performed using a 16-channel technique ...
Bonato P - - 2001
The time-dependent shift in the spectral content of the surface myoelectric signal to lower frequencies has proven to be a useful tool for assessing localized muscle fatigue. Unfortunately, the technique has been restricted to constant-force, isometric contractions because of limitations in the processing methods used to obtain spectral estimates. A ...
Thomas C K - - 2001
The relative roles of motor unit firing rate modulation and recruitment were evaluated when individuals with cervical spinal cord injury (SCI) and able-bodied controls performed a brief (6 s), 50% maximal voluntary contraction (50% MVC; target contraction) of triceps brachii every 10 s until it required maximal effort to achieve ...
Perry S R - - 2001
PURPOSE: The purpose of the present investigation was to examine the mechanomyographic (MMG) and electromyographic (EMG) responses to continuous, constant power output cycle ergometer workbouts. METHODS: Eight adult male volunteers (mean age +/- SD = 22 +/- 2 yrs) performed three continuous, one-hour workbouts at 28, 35, and 42% of ...
Gabriel D A - - 2001
This study monitored the effects of a short-term elbow flexor training program on surface electromyographic (SEMG) spike activity. The experimental paradigm consisted of three test sessions separated by 2-week intervals. At the beginning of each session, participants (N=13) performed five maximal effort isometric contractions of the elbow flexors to serve ...
Niinomi M - - 2001
In order to investigate the effect of molecular weight on fatigue characteristics in the ultra high molecular weight polyethylene (UHMWPE), tension-tension fatigue tests of notched specimens were carried out in the present study. The effects of frequency and stress ratio on the fatigue characteristics were also investigated and fractography was ...
Duchêne J - - 2001
Analysis of long-term surface electromyographic (SEMG) signals has many applications in ergonomics when related to muscle fatigue. The present work proposes a set of processing methods reporting SEMG modifications during long-term driving tests in various situations (with or without head rest). A segmentation/classification algorithm allows signal splitting into homogeneous parts ...
Wittek A - - 2001
Myoelectric signals [electromyograms (EMGs)] can be collected using either surface or fine-wire electrodes. Application of the latter results in higher-frequency contents of EMG. In the field of impact biomechanics, surface electrodes are more often utilized than fine-wire ones. However, the removal of motion artefacts from EMG recorded under transient loads ...
Kiguchi K - - 2001
In order to help everyday life of physically weak people, we are developing exoskeletal robots for human (especially for physically weak people) motion support. In this paper, we propose a one degree-of-freedom (1 DOF) exoskeletal robot and its control system to support the human elbow motion. The proposed controller controls ...
Linnamo V - - 2001
The aim of the present study was to examine changes in the EMG power spectrum and in the maximal M-wave due to different activation levels of eccentric and concentric actions. Average EMG (aEMG) increased as the force increased but no consistent differences were observed in the amplitude of the maximal ...
Hulliger M - - 2001
The experimental simulation method was based upon the separate activation of up to 10 small groups of motor units (MU) in an acute nerve-muscle preparation. The investigator was able to precisely control and systematically alter the features of MU pool activation strategies. No implicit assumptions were made regarding MU properties. ...
Chi-Fishman G - - 2000
This study examined the physiological properties and movement strategies of normal, rapid sequential swallowing during simultaneous videofluoroscopy (VFS) and submental surface electromyography (EMG). Ten subjects performed discrete (5 and 15 cc) and sequential (150 cc in tilted and upright head postures) swallowing tasks. Analyses included VFS event timing, movement/bolus passage ...
von Tscharner V - - 2000
Surface myoelectric signals often appear to carry more information than what is resolved in root mean square analysis of the progress curves or in its power spectrum. Time-frequency analysis of myoelectric signals has not yet led to satisfactory results in respect of separating simultaneous events in time and frequency. In ...
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