Search results for "electrical stimulation"

Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles

2016

International audience; This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT) and doublet frequency train (DFT). Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC) measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd) and tetanic contractions at 80-Hz (P80) and 20-Hz (P20) were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no dif…

Type IV collagen and its degradation in paralyzed human muscle: Effect of functional electrical stimulation

2000

The purpose of this study was to evaluate the effects of spinal cord injury (SCI) and functional electrical stimulation (FES) of paralyzed muscles on type IV collagen content and proteins involving its degradation, which is initiated by matrix metalloproteinase (MMP)-2 and -9 and regulated by their tissue inhibitors (TIMPs)-2 and -1. Ten SCI subjects participated in an 18-month program of functional electrical stimulation (FES) of their leg muscles. Needle biopsies were taken from the vastus lateralis muscle before and at various times during the training period, and from able-bodied controls. Type IV collagen concentration was unaltered. ProMMP-2 level of SCI subjects before the training p…

Effects of Neuromuscular Electrical Stimulation Training on Endurance Performance

2016

Various electrical stimulation modalities are used as adjuvants to conventional training and rehabilitation programs to increase bodily function or to reduce symptoms, such as pain. One of these modalities, neuromuscular electrical stimulation (NMES), commonly refers to the transcutaneous application of electrical currents to a target muscle group with the objective to depolarize motor neurons and consequently elicit skeletal muscle contractions of substantial intensity (usually ranging from 10 to 60% of the maximal voluntary contraction). Because NMES can generate considerable muscle tension, it is frequently used as a strength training technique for healthy adults and athletes, but also a…

Transcranial Electrical and Magnetic Stimulation (tES and TMS) for Addiction Medicine: A Consensus Paper on the Present State of the Science and the …

2019

International audience; There is growing interest in non-invasive brain stimulation (NIBS) as a novel treatment option for substance-use disorders (SUDs). Recent momentum stems from a foundation of preclinical neuroscience demonstrating links between neural circuits and drug consuming behavior, as well as recent FDA-approval of NIBS treatments for mental health disorders that share overlapping pathology with SUDs. As with any emerging field, enthusiasm must be tempered by reason; lessons learned from the past should be prudently applied to future therapies. Here, an international ensemble of experts provides an overview of the state of transcranial-electrical (tES) and transcranial-magnetic…

QT interval heterogeneities induced through local epicardial warming/cooling. An experimental study

2014

[EN] ntroduction and objectives Abnormal QT interval durations and dispersions have been associated with increased risk of ventricular arrhythmias. The present study examines the possible arrhythmogenic effect of inducing QT interval variations through local epicardial cooling and warming. Methods In 10 isolated rabbit hearts, the temperatures of epicardial regions of the left ventricle were modified in a stepwise manner (from 22 °C to 42 °C) with simultaneous electrogram recording in these regions and in others of the same ventricle. QT and activation-recovery intervals were determined during sinus rhythm, whereas conduction velocity and ventricular arrhythmia induction were determined dur…

A novel numerical meshless approach for electric potential estimation in transcranial stimulation

2015

In this paper, a first application of the method of fundamental solutions in estimating the electric potential and the spatial current density distribution in the brain due to transcranial stimulation, is presented. The coupled boundary value p roblems for the electric potential are solved in a meshless way, so avoiding the use of grid based numerical methods. A multi-spherical geometry is considered and numerical results are discussed.

2020

Even though the acute effects of pre-exercise static stretching and dynamic muscle activity on muscular and functional performance have been largely investigated, their effects on the corticospinal pathway are still unclear. For that reason, this study examined the acute effects of 5×20 s of static stretching, dynamic muscle activity and a control condition on spinal excitability, corticospinal excitability and plantar flexor neuromuscular properties. Fifteen volunteers were randomly tested on separate days. Transcranial magnetic stimulation was applied to investigate corticospinal excitability by recording the amplitude of the motor-evoked potential (MEP) and the duration of the cortical s…

Effets aigus et chroniques de l’électrostimulation appliquée au niveau du nerf moteur : importance du retour afférent

2019

The aim of this thesis was to investigate the effects of electrical stimulation protocols favouring an indirect motor units’ (MU) recruitment via sensory axons activation and giving rise to extra force development, on the neuromuscular system. These protocols use wide pulse duration, low stimulation intensity, low and high stimulation frequencies and are applied over the motor nerve. The aim of the first study was to examine the effects of these protocols on the extent and origin of neuromuscular fatigue during an acute application. Results showed that for a similar impact on maximal force generating capacity, low stimulation frequencies limit force decreases during the stimulation trains a…

Arginine Vasopressin Enhances Sympathetic Constriction Through the V1 Vasopressin Receptor in Human Saphenous Vein

1998

Background—Arginine vasopressin (AVP) not only acts directly on blood vessels through V1 receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vivo and in vitro. The aim of the present study was to investigate whether AVP can contribute to an abnormal adrenergic constrictor response of human saphenous veins. Methods and Results—Saphenous vein rings were obtained from 32 patients undergoing coronary artery bypass surgery. The vein rings were suspended in organ bath chambers for isometric recording of tension. AVP (331029 mol/L) enhanced the contractions elicited by electrical field stimulation at 1, 2, and 4 Hz (by 80%, 70%, and 60%, respectively) …

Effects of different lower-limb sensory stimulation strategies on postural regulation-a Systematic review and metaanalysis

2017

Systematic reviews of balance control have tended to only focus on the effects of single lower-limb stimulation strategies, and a current limitation is the lack of comparison between different relevant stimulation strategies. The aim of this systematic review and meta-analysis was to examine evidence of effects of different lower-limb sensory stimulation strategies on postural regulation and stability. Moderate- to high-pooled effect sizes (Unbiased (Hedges' g) standardized mean differences (SMD) = 0.31-0.66) were observed with the addition of noise in a Stochastic Resonance Stimulation Strategy (SRSS), in three populations (i.e., healthy young adults, older adults, and individuals with low…