Search results for "Physical Medicine"
showing 10 items of 1129 documents
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…
Effects of plantar flexor muscle fatigue induced by electromyostimulation on postural coordination
2007
International audience; The aim of the present study was to investigate the influence of a modification of an intrinsic capacity (plantar flexor strength) on the implementation of in-phase and anti-phase mode of coordination. Analysis of hip and ankle relative phases during fore-aft tracking task was done before and after an electromyostimulation fatigue protocol on the soleus muscles. Results showed participants used exclusively in-phase and anti-phase modes of coordination, with a sudden switch from one to the other with target frequency increase. Regarding tracking tasks, fatigue induces a decrease of performance for lower frequencies, and a significant decrease of switch frequency (−0.0…
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…
Abduction nystagmus in internuclear ophthalmoplegia
1992
Direct current electro-oculography revealed abduction nystagmus with hypermetric abduction saccades in 35 of 64 patients with unilateral and 55 of 66 patients with bilateral internuclear ophthalmoplegia. Slowing of abduction saccades occurred in 27 unilateral cases, mainly ipsilateral to the paretic eye, and in 36 bilateral cases. Abduction nystagmus with hypermetric abduction saccades of normal velocity is explained by an increased phasic innervation adjusted to adduction paresis. Slowed abduction saccades are attributed to impaired inhibition of the medial rectus muscle. Superposition of impaired medial rectus inhibition and increased phasic innervation best explains abduction nystagmus w…
Ten-year follow-up of health-related quality of life among ambulatory persons with multiple sclerosis at baseline
2016
Purpose The aim of this 10-year follow-up study was to determine changes in health-related quality of life (HRQoL) over time among ambulatory persons with MS (PwMS) at the baseline using generic and disease-specific instruments. Methods Of 109 independently walking PwMS included in a population-based study in 2002, 77 (70.6 %) were re-assessed in 2012. HRQoL was captured using the 36-Item Short Form Survey Instrument (RAND-36), 15D instrument (15D), and the Multiple Sclerosis Quality of Life-54 (MSQOL-54). Repeated-measures ANOVA and effect size (ES) calculations (Cohen’s d) were used in the statistical analysis. Results The RAND-36 physical health composite score (p = 0.003, ES = 0.26) and…
Reliability of knee extension and flexion measurements using the Con-Trex isokinetic dynamometer.
2007
The aim of this study was to evaluate the reliability of isokinetic and isometric assessments of the knee extensor and the flexor muscle function using the Con-Trex isokinetic dynamometer. Thirty healthy subjects (15 males, 15 females) were tested and retested 7 days later for maximal strength (isokinetic peak torque, work, power and angle of peak torque as well as isometric maximal voluntary contraction torque and rate of torque development) and fatigue (per cent loss and linear slope of torque and work across a series of 20 contractions). For both the knee extensor and the flexor muscle groups, all strength data - except angle of peak torque - demonstrated moderate-to-high reliability, wi…
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…