Search Results
Results 251 - 300 of 681
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Keenan Kevin G - - 2005
The purpose of the study was to quantify the influence of selected motor unit properties and patterns of activity on amplitude cancellation in the simulated surface electromyogram (EMG). The study involved computer simulations of a motor unit population with physiologically defined recruitment and rate coding characteristics that activated muscle fibers ...
Lehman Gregory J - - 2004
This article primarily reviews the assessment of the non-amplitude dependent components of the myoelectric signal in assessing lumbar function in the low back injured and how persons with low back injuries may differ from the non-injured.Assessment of anomalies in function can loosely be categorized into 4 separate protocols: 1. Assessing ...
Manette Olivier F L - - 2004
We investigated spatio-temporal information processing in the primate motor system. Corticomotoneuronal (CM) cells provide monosynaptic excitatory connections from motor cortex to spinal motoneurons and contribute causally to the time-varying electromyogram (EMG) of their target muscle. A multilayer perceptron (MLP) was used to evaluate the transfer function between neural activity of ...
Nene A - - 2004
There is conflicting evidence as to the precise activation pattern of the rectus femoris (RF) muscle during gait in able-bodied subjects. The aim of this study was to determine precise activation pattern of RF during gait in a healthy adult population. Surface and fine wire EMG from RF and vastus ...
Anderson Kenneth G - - 2004
Swiss Balls used as a platform for training provide an unstable environment for force production. The objective of this study was to measure differences in force output and electromyographic (EMG) activity of the pectoralis major, anterior deltoid, triceps, latissimus dorsi, and rectus abdominus for isometric and dynamic contractions under stable ...
Forbes Mitzi A - - 2004
OBJECTIVES: The objective of this preliminary investigation was to determine if surface electromyography (EMG) equipment is capable of detecting electrical signals that can be used as a measure in biofield research. DESIGN: These preliminary data were collected from one subject (a member of the research team), using the subject as ...
Farina Dario - - 2004
In this paper, we propose techniques of surface electromyographic (EMG) signal detection and processing for the assessment of muscle fiber conduction velocity (CV) during dynamic contractions involving fast movements. The main objectives of the study are: 1) to present multielectrode EMG detection systems specifically designed for dynamic conditions (in particular, ...
Holobar A - - 2004
The paper studies a surface electromyogram (SEMG) decomposition technique suitable for identification of complete motor unit (MU) firing patterns and their motor unit action potentials (MUAPs) during low-level isometric voluntary muscle contractions. The algorithm was based on a correlation matrix of measurements, assumed unsynchronised (uncorrelated) MU firings, exhibited a very ...
Zhou Ping - - 2004
Estimates of the number of motor unit action potential (MUAP)s appearing in the surface electromyogram (EMG) signal, which offers potentially valuable information about motor unit recruitment and firing rates, are likely to provide a more accurate reflection of the neural command to muscle than are current EMG quantification methods. In ...
Potvin J R - - 2004
It is generally assumed that raw surface EMG (sEMG) should be high pass filtered with cutoffs of 10-30 Hz to remove motion artifact before subsequent processing to estimate muscle force. The purpose of the current study was to explore the benefits of filtering out much of the raw sEMG signal ...
Wakeling James M - - 2004
Myoelectric signals measured using intramuscular electromyograms (EMGs) in animals have shown that faster motor units generate higher frequencies in their power spectra. However, evidence to relate myoelectric frequency and motor unit type from the surface electromyograms typically measured from man have remained elusive. The purpose of this study was to ...
Brochier T - - 2004
During object grasp, a coordinated activation of distal muscles is required to shape the hand in relation to the physical properties of the object. Despite the fundamental importance of the grasping action, little is known of the muscular activation patterns that allow objects of different sizes and shapes to be ...
Karamanidis Kiros - - 2004
This study examined the validity of the assumption of electromyographic (EMG) and vertical ground reaction force (GRF) parameter reproducibility during running at different velocities and stride frequencies. Each of 12 female long distance runners ran on a treadmill in combinations of three velocities (2.5, 3.0 and 3.5 m/s) and three ...
Osu Rieko - - 2004
There is an infinity of impedance parameter values, and thus different co-contraction levels, that can produce similar movement kinematics from which the CNS must select one. Although signal-dependent noise (SDN) predicts larger motor-command variability during higher co-contraction, the relationship between impedance and task performance is not theoretically obvious and thus ...
Ito Taro - - 2004
The purpose of the present investigation was to explore whether and how the amplitude and/or duration parameters of anticipatory postural adjustments (APAs) affect the upward propulsive force (Delta FZamp) during rising on tiptoes from upright standing position. Seven subjects initiated the movement of rising on tiptoe from a strictly regulated ...
Horemans Herwin L - - 2004
OBJECTIVE: To assess the comparability and reproducibility of 4 questionnaires used to measure fatigue in postpoliomyelitis syndrome (PPS). DESIGN: Repeated-measures at a 3-week interval. SETTING: University hospital. PARTICIPANTS: Convenience sample of 65 patients with PPS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Fatigue Severity Scale (FSS), the Nottingham Health Profile ...
Yan Jingqi - - 2004
This paper presents a novel mesh simplification algorithm. It decouples the simplification process into two phases: shape analysis and edge contraction. In the analysis phase, it imposes a hierarchical structure on a surface mesh by uniform hierarchical partitioning, marks the importance of each vertex in the hierarchical structure, and determines ...
Shapiro Mark B - - 2004
When moving an object, the motor system estimates the dynamic properties of the object and then controls the movement using a combination of predictive feedforward control and proprioceptive feedback. In this study, we examined how the feedforward and proprioceptive feedback processes depend on the expected movement task. Subjects made fast ...
Wada Naomi - - 2004
This chapter addresses the neural control of spinal-column behavior during locomotion. Kinematic and EMG measurements were obtained from the adult cat during its level and upslope treadmill walking. Increasing the grade of upslope walking augmented horizontal movements of the spinal column and decreased its lateral movements. In conjunction, there were ...
Du Y C YC Dept. of Biomedical Eng., Chung Yuan Christian Univ., Chunglee, Taiwan, - - 2004
Both independent component analysis (ICA) and principal component analysis (PCA) were used in this study to evaluate their effects in data reduction in the hand motion identification using surface electromyogram (SEMG) and stationary wavelet transformation. The results indicate that both methods increase the number of training epochs of the artificial ...
Manabe H H Multimedia Laboratories, NTT DoCoMo, Kanagawa, Japan. - - 2004
This paper describes two evaluations of our previously proposed ring shaped EMG measurement system. The first evaluation, based on the collection of EMG by the system, shows that no statistically significant difference is seen between 3 EMG electrode configurations: the electrode is pressed with a finger, the electrode is fixed ...
Baldissera Fausto F Istituto di Fisiologia Umana II, Università degli Studi, Via Mangiagalli 32, 20113 Milano, Italy. - - 2004
During low-frequency (< 1.5 Hz) voluntary oscillations of the foot, placed on a rotating platform, onset of the Tibialis Anterior (TA) EMG paradoxically phase-lags the onset of dorsiflexion, suggesting that initial dorsiflexion is sustained by recoil of elastic structures that were stretched during plantarflexion. It is argued that the lag ...
McMillan Steven S Department of Sport and Exercise Science, University of Auckland, Tamaki Campus, Auckland, New - - 2004
The purpose of this study was to investigate the time-course of corticospinal excitability during reaction time (RT), and compare the excitability when a precue provided information regarding both the direction and extent of the upcoming movement ('Full' condition), specified the direction of the upcoming movement only ('Direction' condition), or provided ...
Farina Dario - - 2004
Single-motor unit (MU) activities were detected from the abductor pollicis and abductor digiti minimi muscles providing the subjects with visual feedback of multichannel surface electromyogram (EMG) signals. The subjects could modulate the force to observe on the surface recordings a single dominant MU and modulate its firing rate for contractions ...
Grassme R - - 2003
OBJECTIVE: An increased spatial resolution in multichannel surface EMG recordings would provide new possibilities for the investigation of intermuscular and intramuscular coordination. A known analytical solution for volume conduction allows the conclusion that a high pass filtered surface electromyography (SEMG) signal contains information from a smaller environment near the recording ...
McClean Michael D - - 2003
Understanding how orofacial muscle activity and movement covary across changes in speech rate and intensity has implications for the neural control of speech production and the use of clinical procedures that manipulate speech prosody. The present study involved a correlation analysis relating average lower-lip and jaw-muscle activity to lip and ...
Alemu M - - 2003
The surface electromyogram (SEMG) is a complex, nonstationary signal. The spectrum of the SEMG is dependent on the force of contraction being generated and other factors like muscle fatigue and interelectrode distance (IED). The spectrum of the signal is time variant. This paper reports the experimental research conducted to study ...
Cheron G - - 2003
This paper describes the use of a dynamic recurrent neural network (DRNN) for simulating lower limb coordination in human locomotion. The method is based on mapping between the electromyographic signals (EMG) from six muscles and the elevation angles of the three main lower limb segments (thigh, shank and foot). The ...
Mündermann Anne - - 2003
PURPOSE: The purpose of this study was to determine the relationship between differences in comfort and changes in lower extremity kinematic and kinetic variables and muscle activity in response to foot orthoses. METHODS: Twenty-one recreational runners volunteered for this study. Three orthotic conditions (posting, custom-molding, and posting and custom-molding) were ...
Hogrel J-Y - - 2003
The aim of this work was to demonstrate the rank order of motor unit (MU) recruitment by surface EMG based on a Laplacian detection technique and to document the MU features at their recruitment threshold. Surface EMG signals were recorded on the biceps brachii of 10 healthy subjects during linear ...
Madigan Michael L - - 2003
The objective of this study was to investigate the effects of LE fatigue on ground impact force, LE kinematics, and LE kinetics during landing. Ground reaction force (GRF), kinematic, and electromyogram (EMG) data were collected from 12 male subjects during a fatiguing landing activity (FLA). This activity allowed not only ...
Chu J - - 2003
INTRODUCTION: Motor unit action potential (MUAP) rise time in quantitative electromyography (QEMG) using multi-MUAP analysis may influence neuromuscular disease diagnosis. OBJECTIVE: To demonstrate in QEMG that MUAP firing rate/frequency (FR) is the parameter least dependent on electrodiagnostician skill (EDXc) skill and selection bias. METHODS AND MATERIALS: During minimal contraction (< ...
Sosnoff Jacob J - - 2004
The current study examined the influence of aging on the oscillatory activity of a population of motor units during rhythmical force production. Previously, it has been shown that aging humans have greater low-frequency and less high-frequency electromyographic (EMG) activity during constant and slow ramp force contractions. We hypothesized that more ...
Masani Kei - - 2003
In literature, it has been suggested that the CNS anticipates spontaneous change in body position during quiet stance and continuously modulates ankle extensor muscle activity to compensate for the change. The purpose of this study was to investigate whether velocity feedback contributes by modulating ankle extensor activities in an anticipatory ...
Nagarajan R - - 2003
The development of suitable techniques for quantifying mechanical and electrophysiological aspects of uterine contractions has been an active area of research. The uterus is a physiological system consisting of a large number of interacting muscle cells. The activity of these cells evolves with time, a trait characteristic of a dynamical ...
Pease William S - - 2003
Electromyographic (EMG) signals are routinely recorded during assessments of biomechanic activity for ergonomic and medical purposes. Surface and intramuscular electrodes (i.m.) are employed by different researchers and there is a continuing need to understand the indications for each. This research evaluated the reproducibility of the shift of the frequency content ...
Ives Jeffrey C - - 2003
OBJECTIVE: To determine if oversampling the surface electromyographic signal provides any benefit in analyzing common electromyographic timing and amplitude measures used in kinesiological studies. DESIGN: A within subjects (n=8) repeated measures design was used to examine surface electromyographic signals captured under four contraction modes and acquired with five different analog-to-digital ...
Reilly Karen T - - 2003
The human flexor digitorum profundus (FDP) sends tendons to all 4 fingers. One might assume that this multitendoned muscle consists of 4 discrete neuromuscular compartments each acting on a different finger, but recent anatomical and physiological studies raise the possibility that the human FDP is incompletely subdivided. To investigate the ...
De Michele Gennaro - - 2003
Using a wavelet analysis approach, it is possible to investigate better the transient and intermittent behavior of multiple electromyographic (EMG) signals during ballistic movements in Parkinsonian patients. In particular, a wavelet cross-correlation analysis on surface signals of two different shoulder muscles allows us to evidence the related unsteady and synchronization ...
Jaberzadeh S - - 2003
An integrated multi-channel AMLAB-based data acquisition, processing and analysis system has been developed to simultaneously display, quantify and correlate electromyographic (EMG) activity, resistive torque, range of motion, and pain responses evoked by passive elbow extension in humans. The system was designed around the AMLAB analog modules and software objects called ...
Judge Larry W - - 2003
The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to ...
Boostani Reza - - 2003
The purpose of this research is to select the best features to have a high rate of motion classification for controlling an artificial hand. Here, 19 EMG signal features have been taken into account. Some of the features suggested in this study include combining wavelet transform with other signal processing ...
Fuglevand Andrew J - - 2003
Motor unit discharge rates decline by about 50 % over 60 s of a sustained maximum voluntary contraction (MVC). It has been suggested that this decline in discharge rate serves to maintain force by protecting against conduction failure and by optimizing the input to motor units as their contractile properties ...
Pincivero D M - - 2003
The aim of this study was to examine superficial quadriceps femoris (QF) EMG and torque at perceived voluntary contraction efforts. Thirty subjects (15 males, 15 females) performed 9, 5 s, sub-maximal contractions at prescribed levels of perceived voluntary effort at points 1-9 on an 11-point scale (0-10), in a random ...
McGarry Tim - - 2003
The ability to inhibit an earlier intended action in a stop-signal task is commonly assessed using the measures of latency and probability. The usual findings from stop-signal trials of lower response probabilities and shorter reaction latencies at reduced stop-signal delays were reported, as described in previous studies in terms of ...
Christou Evangelos A - - 2003
The purpose of the study was to assess the effect of movement velocity on the relation between fluctuations in acceleration and the ability to achieve a target velocity during voluntary contractions performed by young (29.5 +/- 4.3 yr) and old (74.9 +/- 6.2 yr) adults. Subjects performed concentric and eccentric ...
Farina Dario - - 2003
Many spatial filters have been proposed for surface electromyographic (EMG) signal detection. Although theoretical and modeling predictions on spatial selectivity are available, there are no extensive experimental validations of these techniques based on single motor unit (MU) activity detection. The aim of this study was to compare spatial selectivity of ...
Georgakis A - - 2003
The averaged instantaneous frequency (AIF) is proposed as an alternative method for the frequency analysis of surface electromyography (EMG) in the study of muscle fatigue during sustained, isometric muscle contractions. Results from performance analysis using experimental EMG signals demonstrate the low variability of the proposed frequency variable. Indeed, the AIF ...
Dimitrova N A - - 2003
Failure to maintain the required or expected force, defined as muscle fatigue, is accompanied by changes in muscle electrical activity. Although studied for a long time, reasons for EMG changes in time and frequency domain have not been clear until now. Many authors considered that theory predicted linear relation between ...
Hunter A M - - 2003
This study analysed the effect of different electromyographic (EMG) capture rates during maximal voluntary contraction, submaximal and maximal dynamic cycling activity on EMG amplitude and signal characteristics. Ten healthy subjects participated in this study. Peak power output (PPO) and maximal isometric force output (MVC) were measured, followed by a progressive ...
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