Search results for "electromyography"
showing 10 items of 672 documents
Leg stiffness modulation during exhaustive stretch-shortening cycle exercise.
2007
The present study examined the effects of muscle activity modulation on leg stiffness during an exhaustive stretch-shortening cycle (SSC) exercise in eight male subjects. Reaction force, electromyography (EMG) of the soleus (Sol), gastrocnemius (Ga) and vastus lateralis (VL) muscles and sledge seat position were recorded during the SSC exercise, consisting of 100 maximal intermittent drop jumps followed by a continuous submaximal jumping until exhaustion, on a sledge apparatus. Metabolic loading was determined by measuring blood lactate (La). No change was found in leg stiffness during the maximal jumps, whereas the subsequent submaximal jumping induced a significant reduction by 27+/-12% (…
The role of anticipatory postural adjustments during whole body forward reaching movements
1998
THE purpose of this study was to examine the role of anticipatory postural adjustments (APAs) in the execution of forward oriented whole body reaching movements. From the standing position, eight healthy subjects were asked to reach an object placed at 45 cm from the feet, at both naturally paced and fast speeds. Electromyographic signals of six antagonistic muscles were analysed in conjunction with centre of mass (CM) displacements, centre of foot pressure displacements and resultant ground reaction forces. Results revealed that APAs created necessary angular momentum of body segments for effective task execution. These results suggest that APAs can initiate movements conducted from a fixe…
Muscle fatigue affects mental simulation of action.
2011
International audience; Several studies suggest that when subjects mentally rehearse or execute a familiar action, they engage similar neural and cognitive operations. Here, we examined whether muscle fatigue could influence mental movements. Participants mentally and actually performed a sequence of vertical arm movements (rotation around the shoulder joint) before and after a fatiguing exercise involving the right arm. We found similar durations for actual and mental movements before fatigue, but significant temporal discrepancies after fatigue. Specifically, mental simulation was accelerated immediately after fatigue, while the opposite was observed for actual execution. Furthermore, act…
Laterality effects in motor learning by mental practice in right-handers.
2014
Converging evidences suggest that mental movement simulation and actual movement production share similar neurocognitive and learning processes. Although a large body of data is available in the literature regarding mental states involving the dominant arm, examinations for the nondominant arm are sparse. Does mental training, through motor-imagery practice, with the dominant arm or the nondominant arm is equally efficient for motor learning? In the current study, we investigated laterality effects in motor learning by motor-imagery practice. Four groups of right-hander adults mentally and physically performed as fast and accurately as possible (speed/accuracy trade-off paradigm) successive…
Finger movements induced by transcranial magnetic stimulation change with hand posture, but not with coil position
1998
We attempted to map the representations of movements in 2 normal subjects by delivering five transcranial magnetic stimuli (TMS) with a focal coil to each of a grid of positions over the primary motor area (M1). Isometric forces were recorded from the contralateral index finger. Maps were made with the hand in a semiflexed “neutral” position, and with the thumb and index finger opposed in a “pincer” grip. The electromyogram (EMG) was monitored to ensure relaxation. The wrist was immobilized. In the neutral position, TMS at almost all positions produced abduction. Flexion was produced in the pincer position. Thus, while sensitive to changes in posture, TMS mapping may not be sensitive to the…
Publisher Correction: Anticipatory postural adjustments during joint action coordination
2019
There is a current claim that humans are able to effortlessly detect others' hidden mental state by simply observing their movements and transforming the visual input into motor knowledge to predict behaviour. Using a classical paradigm quantifying motor predictions, we tested the role of vision feedback during a reach and load-lifting task performed either alone or with the help of a partner. Wrist flexor and extensor muscle activities were recorded on the supporting hand. Early muscle changes preventing limb instabilities when participants performed the task by themselves revealed the contribution of the visual input in postural anticipation. When the partner performed the unloading, a co…
Electrophysiological patterns of oropharyngeal swallowing in multiple sclerosis.
2012
Abstract Objective We performed an electrophysiological study of swallowing (EPSS) in multiple sclerosis (MS) to describe oropharyngeal swallowing abnormalities and to analyze their correlations with dysphagia and with overall neurological impairment. Methods Neurological examinations were quantified using the Kurtzke Functional Systems and the Expanded Disability Status Scale (EDSS). Dysphagia was evaluated using the Dysphagia in Multiple Sclerosis (DYMUS) questionnaire, while fiberoptic endoscopic evaluation of swallowing (FEES) was used to establish the degree of aspiration and penetration, graded using the penetration–aspiration scale (PAS). The EPSS measured the duration of suprahyoid/…
Cue exposure in alcohol dependent patients: preliminary evidence for different types of cue reactivity.
2000
Craving is considered to be an important phenomenon in addictive behaviours. However, there is still an unresolved debate on what craving for alcohol means, how it is best measured and which clinical and therapeutical consequences its presence or absence may imply. Cue reactivity paradigms have been developed to elicit craving under standardized experimental conditions. Here we present preliminary results characterizing alcohol-dependent patients with regard to subjective and psychophysiological aspects of exposure to alcohol-associated cues in a cue reactivity paradigm. Thirty-six patients fulfilling at least 5 criteria of alcohol dependence according to DSM-IV criteria were studied after …
The ipsilateral corticospinal responses to cross-education are dependent upon the motor-training intervention
2018
This study aimed to identify the ipsilateral corticospinal responses of the contralateral limb following different types of unilateral motor-training. Three groups performing unilateral slow-paced strength training (SPST), non-paced strength training (NPST) or visuomotor skill training (VT) were compared to a control group. It was hypothesised that 4 weeks of unilateral SPST and VT, but not NPST, would increase ipsilateral corticospinal excitability (CSE) and reduce short-interval cortical inhibition (SICI), resulting in greater performance gains of the untrained limb. Tracking error of the untrained limb reduced by 29 and 41% following 2 and 4 weeks of VT. Strength of the untrained limb in…
Electromyographic and patient-reported outcomes of a computer-guided occlusal adjustment performed on patients suffering from chronic myofascial pain
2014
Objectives: Muscular hyperactivity is a potential source of symptoms in patients with temporal-mandibular disorders. An adequate occlusal adjustment may relieve such symptoms. This study aims to measure the effect of shortening the protrusive disclusion time (DT) and balancing the center of occlusal forces (COF) on the EMG recordings and assess the pain reported by chronic patients one month after the computer-guided occlusal adjustment. Study Design: The sample studied comprised 34 patients suffering from chronic facial pain in which the EMG activity of both masseters was recorded by electromyography. By selective grinding we alleviated all the occlusal interferences during the mandibular …