Search results for "Myograph"
showing 10 items of 689 documents
Practice-Related Improvements in Postural Control During Rapid Arm Movement in Older Adults: A Preliminary Study
2012
International audience; Background. Postural control associated with self-paced movement is critical for balance in older adults. The present study aimed to investigate the effects of a virtual reality based program on the postural control associated with rapid arm movement in this population. Methods. From an upright standing position, participants performed rapid arm raising movements toward a target. Practice-related changes were assessed by pre- and posttest comparisons of hand kinematics and center of pressure displacement parameters measured in a training group (mean age: 71.50 +/- 2.67 years, n = 8) and a control group (mean age: 72.87 +/- 3.09 years, n = 8). Training group participa…
Associations of age, body size, and maturation with physical activity intensity in different laboratory tasks in children.
2021
We investigated the associations of age, sex, body size, body composition, and maturity with measures of physical activity (PA) intensity in children. PA intensity was assessed using VO2 as % of VO...
Self-Relevance Appraisal Influences Facial Reactions to Emotional Body Expressions
2013
International audience; People display facial reactions when exposed to others' emotional expressions, but exactly what mechanism mediates these facial reactions remains a debated issue. In this study, we manipulated two critical perceptual features that contribute to determining the significance of others' emotional expressions: the direction of attention (toward or away from the observer) and the intensity of the emotional display. Electromyographic activity over the corrugator muscle was recorded while participants observed videos of neutral to angry body expressions. Self-directed bodies induced greater corrugator activity than other-directed bodies; additionally corrugator activity was…
Neuromuscular Fatigue Is Not Different between Constant and Variable Frequency Stimulation
2014
International audience; This study compared fatigue development of the triceps surae induced by two electrical stimulation protocols composed of constant and variable frequency trains (CFTs, VFTs, 450 trains, 30 Hz, 167 ms ON, 500 ms OFF and 146 ms ON, 500 ms OFF respectively). For the VFTs protocol a doublet (100 Hz) was used at the beginning of each train. The intensity used evoked 30% of a maximal voluntary contraction (MVC) and was defined using CFTs. Neuromuscular tests were performed before and after each protocol. Changes in excitation-contraction coupling were assessed by analysing the M-wave [at rest (M-max) and during MVC (M-sup)] and associated peak twitch (Pt). H-reflex [at rest…
Body schema plasticity after stroke: subjective and neurophysiological correlates of the rubber hand illusion
2017
[EN] Stroke can lead to motor impairments that can affect the body structure and restraint mobility. We hypothesize that brain lesions and their motor sequelae can distort the body schema, a sensorimotor map of body parts and elements in the peripersonal space through which human beings embody the reachable space and ready the body for forthcoming movements. Two main constructs have been identified in the embodiment mechanism: body-ownership, the sense that the body that one inhabits is his/her own, and agency, the sense that one can move and control his/her body. To test this, the present study simultaneously investigated different embodiment subcomponents (body-ownership, localization, an…
The Hemodynamic Effects of Ephedrine on the Onset Time of Rocuronium in Pigs
2004
Several studies have found a correlation between the onset time of muscle relaxants, cardiac index, and muscle blood flow. Ephedrine increases these hemodynamic variables and shortens onset time of rocuronium in humans. Our aim in this animal study was to determine the effect of ephedrine on the onset time of rocuronium, cardiac index, and muscle blood flow after administration of thiopental. At predefined measuring points, mean arterial blood pressure and cardiac index were measured invasively and onset time was determined mechanomyographically. Twenty-four pigs were randomly assigned to three groups. Group I received etomidate and subsequently rocuronium (2 x 95% effective dose). Instead …
Aberrant arrested in maturation neuromuscular junctions in centronuclear myopathy
1994
Unusual ultrastructural changes of the nerve terminals have been found in an infant born with severe, fatal XLR form of centronuclear myopathy. Aberrant neuromuscular junctions in myotubes decorated by N-CAM were observed. The junction changes were manifested by simplification of postsynaptic membrane and paucity of secondary synaptic clefts. These resembles fetal neuromuscular junctions. The findings suggest that the expression of N-CAM by arrested myotubes may be promoted by abnormal nerve-muscle cell interactions, induced by motor endplate immaturity.
Changes in intracortical circuits of the human motor cortex following theta burst stimulation of the lateral cerebellum
2008
Objective: The cerebellum takes part in several motor functions through its influence on the motor cortex (M1). Here, we applied the theta burst stimulation (TBS) protocol, a novel form of repetitive Transcranial Magnetic Stimulation (rTMS) over the lateral cerebellum. The aim of this study was to test whether TBS of the lateral cerebellum could be able to modulate the excitability of the contralateral M1 in healthy subjects. Methods: Motor-evoked potentials (MEPs) amplitude, short intracortical inhibition (SICI), long intracortical inhibition (LICI) and short intracortical facilitation (SICF) were tested in the M1 before and after cerebellar continuous TBS (cTBS) or intermittent TBS (iTBS)…
Fatigue in a simulated cross-country skiing sprint competition
2009
The aim of this study was to assess fatigue during a simulated cross-country skiing sprint competition based on skating technique. Sixteen male skiers performed a 30-m maximal skiing speed test and four 850-m heats with roller skies on a tartan track, separated by 20 min recovery between heats. Physiological variables (heart rate, blood lactate concentration, oxygen consumption), skiing velocity, and electromyography (EMG) were recorded at the beginning of the heats and at the end of each 200-m lap during the heats. Maximal skiing velocity and EMG were measured in the speed test before the simulation. No differences were observed in skiing velocity, EMG or metabolic variables between the he…
Effect of skiing speed on ski and pole forces in cross-country skiing.
2008
Purpose: The present study characterized pole and ski forces in classical technique cross-country skiing. Eight elite junior cross-country skiers performed diagonal skiing at 65%, 75%, 90%, and 100% of maximum speed on a stable 100-m-low uphill (2.5[degrees]). Method: The ski and the pole forces (vertical (Fz) and horizontal (Fy) directions) on the right and left sides were recorded separately when the skier skied over a special custom-made force platform system placed at the end of the uphill course. The entire system consisted of four separate 20-m-long rows of 1-m-long force plates connected in series, row by row. Results: When the forces were averaged for the various functional phases o…