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Results 351 - 400 of 681
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Ward A R - - 2000
The most commonly used stimulus for functional electrical stimulation is low frequency, short duration pulsed current. A disadvantage is the associated rapid fatigue. The present study investigated the effect of kHz frequency alternating currents on the rate of fatigue with electrically induced skeletal muscle contractions in normal subjects. Alternating current ...
Lowery M M - - 2000
Spectral compression of the electromyographic (EMG) signal, due largely to decreasing muscle fiber conduction velocity, is commonly used as an indication of muscle fatigue. Current methods of estimating conduction velocity using characteristic frequencies such as the median frequency of the power spectrum, are based on an assumption of uniform spectral ...
Sumitsuji N - - 2000
Since Darwin (1872), the origin of the laugh with an intermittent exhalation "A! Ha! Ha!" which is peculiar to human, has been a great question. The author found out that this laugh is caused by the three sets of emotion. Firstly, light surprise or discovery. The ability to estimate "light" ...
Baldissera F F Istituto di Fisiologia Umana II, Università degli Studi, Milan, Italy. - - 2000
(1) Rhythmic flexion-extensions of the hand and foot on one side were performed by ten male and nine female subjects. Limbs were rotated in the same direction (in-phase) or in opposite directions (anti-phase). Oscillation frequency ranged from 0.6 to 3.2 Hz for in-phase and to 2.2 Hz for anti-phase movements. ...
Habu S - - 2000
Diurnal motor activities of the upper, middle, and lower thirds of the thoracic esophagus, the lower esophageal sphincter, and the gastric body were recorded in six conscious dogs, using extraluminal force transducers. The motor activities of the thoracic esophagus and the lower esophageal sphincter were divided into three major motility ...
Swanson S C - - 2000
PURPOSE: Recent sprint training regimens have used high-speed incline treadmill running to provide enhanced loading of muscles responsible for increasing forward running speed. The goal of this study was to document the joint kinematics, EMG, and swing-phase kinetics of incline treadmill running at 4.5 m x s(-1) with a 30% ...
Latash M L - - 2000
OBJECTIVE: Within this study, we tested a hypothesis that common organization of central commands to the elbow and the wrist joints within a two-joint synergy is associated with a similar organization of pre-programmed corrections to unexpected changes in the external conditions. DESIGN AND METHODS: The subjects (n = 7) performed ...
Trimble M H - - 2000
Maximal torque during the concentric phase of a movement has been shown to be enhanced by prior eccentric muscle actions, a movement strategy referred to as the stretch-shortening cycle. Although the mechanical basis for this enhancement is well established, the neural component is not. We hypothesized that brief high-frequency bursts ...
Clancy E A - - 2000
Previous research showed that whitening the surface electromyogram (EMG) can improve EMG amplitude estimation (where EMG amplitude is defined as the time-varying standard deviation of the EMG). However, conventional whitening via a linear filter seems to fail at low EMG amplitude levels, perhaps due to additive background noise in the ...
McLoda T A - - 2000
OBJECTIVE: To determine the most efficient burst duty cycle for eliciting an involuntary quadriceps femoris contraction in healthy subjects. This information will allow clinicians to make an informed decision about the optimal burst duty cycle based upon a specific treatment goal. The logical goal for such a treatment choice is ...
Spotts V J - - 2000
In order to determine if differences in human muscle EMG response to steady-state (STD) dynamic load and transient (TRN) load could be detected, two distinct sinusoidal loads having identical amplitude and frequency were applied to the forearm, which was held in a fixed posture. The first condition used application of ...
McLean L - - 2000
Myoelectric signal (MES) behaviour was studied during prolonged, sustained, low level contractions using a portable system with limited data storage capacity. A pre-processing technique is described which overcomes memory and data storage limitations in a portable multichannel MES data logger. This technique for data reduction was used to study MES ...
Sapir S - - 2000
Nineteen healthy young adult males with normal voice and speech attempted to sustain the vowel /u/ at a constant pitch (target: 180 Hz) and a constant and comfortable loudness level while receiving a sudden mechanical perturbation to the larynx (thyroid prominence) via a servo-controlled probe. The probe moved toward or ...
Hodges P W - - 2000
The co-ordination between respiratory and postural functions of the diaphragm was investigated during repetitive upper limb movement. It was hypothesised that diaphragm activity would occur either tonically or phasically in association with the forces from each movement and that this activity would combine with phasic respiratory activity. Movements of the ...
Wang R Y - - 2000
Spasticity is mostly due to an excess of impulses to alpha motor neurons partly resulting from a change of interneuron activity. Low threshold afferent has been reported to change the activity in interneuron. The purpose of this study is to investigate the effects of surface spinal paravertebral stimulation on knee ...
Gerard M J - - 1999
The effects of keyswitch stiffness and key action on typing force, electromyography (EMG), and subjective preference were examined. Each subject's own keyboard (with an audible key click and key activation force of 0.72 N) and three keyboards with no key click that were identical in design but had different key ...
Udo H - - 1999
The purpose of this study was to examine the possible effects of a tilting seat on the back, lower back and legs. Ten healthy male subjects aged 22-28 performed word-processing operations while sitting on a chair for one hour under two different seating conditions: the rocking condition and the fixed ...
Dewar H - - 1999
We report the development of an acoustic telemetry tag used to monitor electromyograms (EMGs) remotely from free-swimming marine fish. The device described amplifies and filters the EMG and then converts the electrical waveform into a frequency-modulated acoustic signal that is transmitted through water. The signal is then received, demodulated and ...
Morrison S - - 1999
Triphasic electromyographic (EMG) patterns have been described as characteristic of rapid, discrete, uniplanar, goal-directed movements. This experiment examined the effects of Response Type (experimenter- vs. subject-determined), Hand (preferred vs. nonpreferred), and Practice (early vs. late) on performance accuracy, and specific temporal EMG and kinematic measures during a dart throw. EMG ...
Bazzotti L - - 1999
On a population of 52 subjects surface electromyographic recordings of temporals and masseters, simultaneously with mandible dynamic of closure and clenching, were performed, in order to study tension and frequency behaviour in three postural conditions: rest, isotonic and isometric contractions. Frequency was studied using the median resulting from FFT calculation, ...
Wackerbauer Renate - - 1999
Different studies of the irritable bowel syndrome (IBS) by conventional analysis of jejunal motility report conflicting results. Therefore, our aim is to quantify the jejunal contraction activity by symbolic dynamics in order to discriminate between IBS and control subjects. Contraction amplitudes during fasting motility (phase II) are analyzed for 30 ...
Dörge H C - - 1999
The purpose of the study was to develop a method to record intramuscular electromyogram (EMG) from the iliopsoas muscle and to relate this activity to the kinetics during the soccer place kick. Seven skilled soccer players performed 3 maximal velocity place kicks. The kicks were filmed with a high-speed camera ...
Sun T Y - - 1999
To noninvasively estimate the motor unit size, we present a novel surface electromyographic (EMG) measurement system consisting of a surface multielectrode with four-pin electrodes and a pair of surface-disk electrodes. Surface motor unit action potentials (MUAPs) were recorded with the multielectrode, in the so-called multielectrode surface EMG (MSEMG), which was ...
Filligoi G - - 1999
The analysis of the surface electromyographic (sEMG) signal is particularly attractive because it provides relatively easy access to those physiological processes that allow the muscle to generate force and movement. In this paper, one of the possible applications of recurrence plot strategy to the analysis of sEMG is described. Recurrence ...
Clancy E A - - 1999
Typical electromyogram (EMG) amplitude estimators use a fixed window length for smoothing the amplitude estimate. When the EMG amplitude is dynamic, previous research suggests that varying the smoothing length as a function of time may improve amplitude estimation. This paper develops optimal time-varying selection of the smoothing window length using ...
Recktenwald M R - - 1999
Effects of spaceflight on Rhesus quadrupedal locomotion after return to 1G. Locomotor performance, activation patterns of the soleus (Sol), medial gastrocnemius (MG), vastus lateralis (VL), and tibialis anterior (TA) and MG tendon force during quadrupedal stepping were studied in adult Rhesus before and after 14 days of either spaceflight (n ...
Valls-Solé J - - 1999
1. The reaction time to a visual stimulus shortens significantly when an unexpected acoustic startle is delivered together with the 'go' signal in healthy human subjects. In this paper we have investigated the physiological mechanisms underlying this effect. If the commands for the startle and the voluntary reaction were superimposed ...
Rudel D - - 1999
OBJECTIVE: To study the activity of the human uterine cervix at the onset of labour and further characterise cervical asynchronous electromyographic (EMG) activity in the latent phase. DESIGN: Prospective observational study. SETTING AND PARTICIPANTS: Clinical hospital in Ljubljana. PARTICIPANTS: Forty-seven healthy nulliparous women with relatively unripe cervices requiring induction of ...
Kameyama J - - 1999
The purpose of this study is to create the standard stimulation patterns of shoulder motion from electromyographic (EMG) data in 13 healthy human volunteers in order to control the movement of the paralyzed shoulder in quadriplegic and hemiplegic patients by functional electrical stimulation (FES). Simultaneous EMG measurement was made at ...
Disselhorst-Klug C - - 1999
For research as well as diagnostic applications the non-invasive detection of the activity of single motor units is of interest. The most direct information is expected to be found in monopolarly recorded data. But when an array of surface electrodes is used for the monopolar recordings of the potential distribution ...
Harba M I - - 1999
Cross-correlating two surface EMG signals detected at two different locations along the path of flow of action potential enables the measurement of the muscle fiber average conduction velocity in those active motor units monitored by the electrodes. The position of the peak of the cross-correlation function is the time delay ...
Hamm T M - - 1999
The patterns of correlation found between motoneuron pools during fictive locomotion are the same whether the coherence functions used to detect the correlations are determined using pairs of rectified ENGs or motoneuron LDPs and rectified ENGs. This finding suggests that the higher frequencies in rectified ENGs (and, perhaps, EMGs) contain ...
Gabriel D A - - 1998
The effect of repeated maximal effort isotonic contractions on electromechanical delay was studied. Over 4 days, 17 male subjects performed 400 rapid elbow flexion trials. The kinematics and surface electromyographic (EMG) activity of the biceps brachii of these subjects were recorded. The period from the onset of the EMG until ...
Baratta R V - - 1998
Three methods that can significantly reduce the variability of the EMG power density spectrum (PDS) variable by eliminating artifactual components are described. Two methods, one that allows the subtraction of power line noise in the time domain and one which allows the subtraction of system noise in the frequency domain ...
Feng C J - - 1998
Surface electromyography (EMG) signals were measured from the biceps brachii (BIC), the brachioradialis (BRD) and the triceps brachii (TRI) of seven young adults with pure spastic quadriplegia and eight normal individuals. The signals were analyzed in both the time domain and the frequency domain. The subjects sat in an adjustable ...
Laursen B - - 1998
To study the potentiality for developing an EMG-based model for the human shoulder, mapping of relations between static hand forces and electromyographic (EMG) activity of 13 shoulder muscles, were performed. The procedure was to perform by the hands slowly varying isometric forces up to 20% maximum voluntary force in the ...
Brereton L C - - 1998
During muscle contraction, electrical activity necessarily precedes force output, yet models that utilize processed electromyograms sometimes predict force as preceding EMG under rapid ballistic loading conditions. The purpose of this study was to define the frequency response transfer function of the upper and lower erector spinae musculature, at different lengths ...
Roy S H - - 1998
A new approach to estimating the frequency compression of the surface EMG signal during cyclical dynamic exercise is described. The basic properties of the method are first developed using simulated EMG signals. Spectral compression is measured by defining the instantaneous median frequency from time-frequency representations of the signal derived from ...
Tanaka T H - - 1998
Thirty healthy subject's left and right lumber paraspinal (LP) EMG activity was recorded during a trunk flexion-return movement and the maximum integrated EMG amplitude (absolute EMG) during this movement in each side was compared. Twenty subjects showed less than 20% difference between the left and right side (symmetrical subjects-SS) and ...
Kjellberg K - - 1998
In the present study work technique was viewed in two basic elements: the method of carrying out a work task and the individual performance of the work task. The aim was to investigate how eight selected kinematic, kinetic, electromyographic and psychophysical variables can characterize the two elements of work technique. ...
Cairns A M - - 1998
Power spectra were derived from the diaphragm electromyogram (EMG) in anesthetized rabbits subjected to inspiratory resistive loading (IRL) with airway pressure swings of 40-60 cm H2O for 20 min to 2 h. Shifts in the centroid frequencies of the power spectra were found to be associated with the appearance of ...
Prilutsky B I BI Department of Health and Performance Sciences, Center for Human Movement Studies, The Georgia Institute of Technology, Atlanta 30332-0110, - - 1998
It has been hypothesized previously that because a strong correlation was found between the difference in electromyographic activity (EMG) of rectus femoris (RF) and hamstrings (HA; EMG(RF)-EMG(HA)) and the difference in the resultant moments at the knee and hip (Mk-Mh) during exertion of external forces on the ground by the ...
Clancy E A - - 1998
Multiple-channel electromyogram (EMG) amplitude estimators incorporating temporal whitening filters and/or spatial uncorrelation filters contain a characterization of the EMG waveform (specifically, auto- and cross-correlation information) which may vary with joint angle. This paper reports on an experimental study which investigated the influence of joint angle on these EMG amplitude estimators. ...
Cousins M S - - 1998
Rats were implanted with fine-wire electromyograph (EMG) electrodes and were videotaped to identify the local frequency characteristics and muscle activity associated with tacrine-induced tremulous jaw movements. All rats received intraperitoneal injections of 2.5 mg/kg tacrine. The videotape sessions were played back in slow motion (i.e., one-sixth normal speed), and an ...
Chisari C - - 1998
A motor point stimulation protocol was carried out on the tibialis anterior of myotonic dystrophy (MyD) patients. The surface myoelectric signal was monitored to record average rectified value (ARV), median frequency of power spectrum (MDF), and conduction velocity (CV) parameters. The ARV curve showed a decreasing trend that reveals a ...
Gabriel D A - - 1998
This study examined changes in antagonist timing and magnitude in response to ballistic elbow flexion practice. Seventeen men performed 400 ballistic elbow flexion trials to a target in the horizontal plane over 4 days of testing. A potentiometer and microswitch system at the elbow axis of rotation of a manipulandum ...
Kasprisin J E - - 1998
Electromyography (EMG) is a commonly used tool that can be plagued with poor signal-to-noise ratios. One result of poor signal-to-noise ratios is increased within- and between-subject variability of quantified EMG variables, for example, the integrated EMG. Methods that reduce within- and between-subject variability of quantified EMG variables can increase the ...
Oh S A - - 1998
This study used a computer-controlled electric right angle nutrunner to investigate the relative effects of different power hand tool and process parameters on operator muscular exertions, handle stability and subjective ratings of perceived exertion. Target torque (25, 40 and 55 Nm), torque build-up time (35, 150, 300, 500 and 900 ...
Wick HS - - 1998
This study attempted to identify a direct relationship between the design characteristics of a manually-assembled product, exposure to work-related ergonomic risk factors, and improvement in product quality. The study considered (a) Accessibility (ease of approach) and Guidance (ease of alignment and positioning) as Design Variables, (b) Shoulder Abduction, Trunk Lateral ...
Van Cutsem M - - 1997
The present work was carried out to analyse the properties and behaviour of Tibialis anterior motor units (MUs) during voluntary contractions in humans. A total of 528 single MU mechanical properties was recorded in 10 subjects by means of the spike-triggered averaging (STA) technique. MU recruitment thresholds and discharge frequencies ...
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