Search results for "Motor"
showing 10 items of 3137 documents
Case study: effect of handrim diameter on performance in a paralympic wheelchair athlete.
2009
This study, with a top T-52 class athlete, determines the relationship between stroke frequency (SF) and push time (PT) and wheelchair velocity (Wv) using different handrim diameters (HD) and the effect of different HDs on the athlete’s heart rate (HR) and blood lactate (LACT) at competition speeds. Wv shows a linear-direct relationship with SF but a linear-inverse relationship with PT (p < .001 in both cases). Using bigger handrims (0.37 m instead of 0.36 m), SF increases 6%, while PT decreases 27% (at 24 Km·h–1). HR (p < .0001) increases with Wv and is also affected by HD with differences between the 0.34 m—0.36 m handrim group (lower values) and the 0.37 m handrim (higher values). …
The Bandwidth of VWM Consolidation Varies With the Stimulus Feature: Evidence From Event-Related Potentials
2018
Our previous work suggests that 2 colors can be consolidated into visual short-term memory (VSTM) in parallel without a loss of memory precision, whereas consolidation of 2 orientations is performed in a strictly serial manner. Those experiments compared VSTM performance for simultaneously and sequentially presented stimuli. However, there is still controversy about whether the bandwidth for consolidation is determined by the type of information. To further investigate this issue, here we measured electroencephalography while participants attempted to consolidate 1, 2 or 4 simultaneously presented colors (Experiment 1) or orientations (Experiment 2) under limited presentation times. We used…
A multidisciplinary approach to assess recovery of consciousness in a patient with moyamoya disease
2019
Abstract Introduction Moyamoya disease (MMD) meaning “hazy puff of smoke” in Japanese is a rare chronic cerebrovascular syndrome characterized by progressive stenosis and occlusion of the internal carotid arteries (ICAs) anterior cerebral arteries (ACAs), and middle cerebral arteries (MCAs). Methods Our moyamoya patient with severely impaired cognitive and motor functions underwent a specific motor and neuropsychological rehabilitative treatments to assess the recovery of consciousness. Results Results obtained showed an improvement of clinical and neuropsychological examination. These findings highlighted the importance of an intensive rehabilitation techniques used in the care of disorder…
Motor Unit Firing Behaviour of Soleus Muscle in Isometric and Dynamic Contractions
2012
Introduction. Understanding the detailed control of human locomotion and balance can be improved, when individual motor units can be isolated and their firing rates followed in natural movement of large, fuctionally important muscles. For this reason the present study investigated the motor unit discharge rate (MUDR) in isometric and dynamic contractions of the soleus muscle. Methods: Eleven males performed isometric (10–100% MVC) and dynamic (10–40% MVC) plantar flexions. Intramuscular EMG was measured from Soleus with bipolar wire-electrodes and decomposed with custom built “Daisy” software. Results. The Soleus MUDR was significantly higher in concentric compared to isometric or eccentric…
Multi-channel electromyography during maximal isometric and dynamic contractions.
2013
Motor unit behavior differs between contraction types at submaximal contraction levels, however is challenging to study during maximal voluntary contractions (MVCs). With multi-channel surface electromyography (sEMG), mean physiological characteristics of the active motor units can be extracted. Two 8-electrode sEMG arrays were attached on biceps brachii muscle (one on each head) to examine behavior of sEMG variables during isometric, eccentric and concentric MVCs of elbow flexors in 36 volunteers. On average, isometric (364 ± 88N) and eccentric (353 ± 74N) MVCs were higher than concentric (290 ± 73N) MVC (p0.001). Mean muscle fiber conduction velocity (CV) was highest during eccentric MVC …
Neuromuscular Fatigue Following Isometric Contractions with Similar Torque Time Integral
2014
International audience; Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25 %, 50 %, and 75 % of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5 +/- 33.4 s, 35.1 +/- 16.8 s and 24.8 +/- 12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately a…
Analysis of F-wave in metabolic neuropathies: a comparative study in uremic and diabetic patients.
1987
Motor nerve conduction study along the entire length of the ulnar and tibialis posterior nerves was carried out in 30 diabetics compared with 30 uremic patients and 30 control subjects. The conduction in the proximal and the distal nerve segments was evaluated by the determination of the M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites), and F-ratio (conduction time ratio of proximal to distal segment). In both groups of patients the lower limbs appear much more involved than the upper, where the ulnar nerve is more commonly affected in uremic than in diabetic patients. In diabetic neuropathy the motor conduction abnormalities are di…
Differences in pitch between tones affect behaviour even when incorrectly identified in direction.
2001
The ability to detect differences between simultaneously presented contra- and ipsilesional stimuli but not to identify the former on neurological patients with the symptom termed 'extinction' has given rise to the hypothesis that extinguished stimuli have impaired access to attentive processing but are detected pre-attentively. Such a dissociation found in normal participants with experimentally degraded sensory information, and its absence in equivalent tasks in terms of the amount of information required has, however, led to an alternative hypothesis that the lesser amount of information required to perform same/different judgements is sufficient to explain this dissociation. In the pres…
Dissociation of emotional processes in response to visual and olfactory stimuli following frontotemporal damage.
2005
Contemporary neuropsychological studies have stressed the widely distributed and multicomponential nature of human affective processes. Here, we examined facial electromyographic (EMG) (zygomaticus and corrugator muscle activity), autonomic (skin conductance and heart rate) and subjective measures of affective valence and arousal in patient TG, a 30 year-old man with left anterior mediotemporal and left orbitofrontal lesions resulting from a traumatic brain injury. Both TG and a normal control group were exposed to hedonically valenced visual and olfactory stimuli. In contrast with control subjects, facial EMG and electrodermal activity in TG did not differentiate among pleasant, unpleasant…
EMG frequency spectrum, muscle structure, and fatigue during dynamic contractions in man
1979
Fatigue of the vastus lateralis muscle was studied in healthy well-conditioned students, who differed considerable regarding their muscle fibre type distribution. Muscle force decline during repeated maximum voluntary knee extensions at a constant angular velocity (180 degree X s-1 or rad X s-1), using isokinetic equipment, was taken as the criterion for the degree of fatigue. In an attempt to study quantitative as well as qualitative changes in the EMG pattern, integrated EMG (IEMG) and the frequency of the mean power (MPF), computed from the power spectral density function (PSDF), were analysed. It was found that individuals with muscles made up of a high proportion of fast twitch (FT) mu…