Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 57 for “"Voluntary Contraction"”.
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Control of human motoneurones during voluntary contraction and fatigue
… control of human motoneurones during voluntary contraction and fatigue. First, output of motoneurones to corticospinal inputs is described for a wide range of contraction strengths. Results show that motoneurones become less responsive during strong contractions whereas motor cortical …
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Motor unit firing rate control of agonist skeletal muscle during voluntary isometric and shortening contractions with limb movement
Voluntary movements throughout mammalian lifespan require skeletal muscle contractions that are controlled by time- and recruitment-dependent firing rate patterns. Single motor unit (MU) activity reflects the final efferent neural drive to the muscle, yet the underlying neural control of movement …
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Behaviour of single motor units in human skeletal muscle
… of motor units at particular grades of isometric contraction depend on the total number of units available for recruitment and so are regulated by length and tension receptors in the muscle. Procainisation showed the importance of the gamma- regulated length receptors in voluntary contraction. In …
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Effect of Shoulder Angle on the Activation Pattern of the Elbow Extensors During a Submaximal Isometric Fatiguing Contraction
… of the elbow extensors during a fatiguing contraction. METHODS: Ten young men (23.5 ± 1.7) were tested on two occasions with the shoulder at either 0° or 90° of flexion. Baseline isometric maximum voluntary contraction torque and the EMG-torque relationship were determined prior to a …
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The reliability of an isometric test based on constant perception of effort
… control neuromuscular output during an isometric contraction. 21 varsity athletes completed a maximal voluntary contraction and a 2 min constant force contraction at both the start and end of the study. Between pre and post testing all participants completed a 2 min constant perceived exertion …
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Functional Anatomy of the Anconeus: Muscle Architecture and Motor Unit Number Estimation
… MUNEs at forces higher than ~30% of a maximum voluntary contraction. Unique features of the anconeus muscle may permit MUNEs at higher muscle activation levels. Thus, the purpose of Chapter 3 was to estimate the number of functional MUs in the anconeus, using DE-STA, at low (10%), moderate …
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Biomechanics Of Slips In Alternative Footwear
… selection and were tested for maximal voluntary contraction for lower extremity muscles and were exposed to a series of walking trails that included a normal dry surface non slip gait trial (ns); unexpected slip (us), alert slip (as) and expected slip (es). A 3 x 4 [3 (ff, cc, lt) x 4 …
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Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Does Not Improve Handgrip Time-to-Failure or Alter Central or Peripheral Hemodynamics
… Twenty-five participants completed five maximal voluntary contractions, followed by 20-minutes of a-tDCS or SHAM conditions. Next, participants completed a handgrip time-to-failure task by maximally squeezing an electronic handgrip dynamometer until they could no longer maintain 50% of their …
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The Assessment of Autonomic Function in Young Adults with an Elevated Risk of Metabolic Syndrome
… 8 minutes of rhythmic handgrip at 25% maximal voluntary contraction (MVC), where HR, beat-by-by BP, and tissue oxygen saturation index (TSI) were recorded continuously. The change in mean arterial pressure vs the change in TSI were plotted to produce a slope quantifying the magnitude of the …
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The Role of Dopamine on Central Neuromuscular Activation during Passive Hyperthermia
… Neuromuscular responses, as indicated by maximal voluntary contraction (MVC) force, and voluntary activation (VA) percentage were assessed prior to drug ingestion, 1 hour after MPH wash-in, throughout the heating protocol and at cessation of heating. A primary non-significant finding of this …
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Required force level and isometric tracking
… force levels scaled to the isometric maximum voluntary contraction (MVC) of elbow extension for each subject. It was hypothesized that higher frequencies of forcing function (5 levels) and higher required force levels (5 levels) would result in degraded tracking performance. The dependent …
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The surface electromyography-force relationship during isometric dorsiflexion in males and females
… males and 50 females) performed three isometric contractions at 20, 40, 60, 80, and 100% of maximal voluntary contraction (MVC) in an apparatus designed to isolate the action of the dorsiflexors. The surface EMG signal was amplified (lOOOx), band-pass filtered (10-500Hz), and sampled at 2048 Hz. …
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An Electromyographical Analysis of Shoulder and Trunk Muscles During Chest Press on Stable and Unstable Platforms
… that this discrepancy is caused by a co-contraction mechanism at the glenohumeral joint, favoring joint stability over force production. The purpose of this study was to examine the effect of instability on agonist, antagonist, and core musculature during the supine chest press. …
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The Effect of Exercise on Mechanical Pressure Pain Threshold in the Presence and Absence of Delayed-Onset Muscle Soreness
… consisted of participants holding 25% of maximum voluntary contraction strength (MVC) till fatigue, defined as a drop in force of 25%. Pressure pain threshold was taken in each thigh every 30 seconds during exercise, 2-minutes post, and 15-minutes post exercise, as well as before and after …
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Effect of Electrode Size, Shape, and Placement on Electrical Current and Subject Comfort During Electrical Stimulation
… of each extremity. After determining the maximal voluntary contraction (MVC) of the muscle and careful determination of the motor point, ES, with a biphasic square wave of 300 ms duration and a frequency of 30 Hz, was used to bring the muscle to 10% MVC. Subject tolerance to ES was recorded using …
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Interaction of voluntary activity and functional electrical stimulation in the upper extremity as a method for short-term alteration of corticospinal excitability and force control
… are unable to participate in RMT. The effects of voluntary contraction and FES are not well understood for the upper extremity following a stroke. This experiment was designed to elucidate the mechanisms of functional and neurophysiological changes associated with combining FES and voluntary …
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The Effect of Positioning on Pelvic Floor Muscle Activity as Evaluated with Surface Electromyography in Normals
… Practitioners compare resting tone, maximal contraction, and muscle endurance measures before and after pelvic floor exercise instruction to determine intervention and demonstrate progress. There is little research that supports the use of biofeedback in positions other than supine. The …
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Impedance Changes in Biceps Brachii Due to Isometric Contractions and Muscle Fatigue Using Electrical Impedance Myography (EIM)
… between muscles at rest and during isometric contractions at various force levels(25%, 50%, and 100% of maximum voluntary contraction) of the biceps brachii over a multifrequency spectrum. Impedance measurements due to muscle fatigue was further studied and compared to muscles under static …
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The effects of prostaglandin inhibition on the sympathetic and pressor responses to muscular contraction and postcontraction muscle ischemia
… to isometric handgrip (HG) at 40% of maximal voluntary contraction (MVC) to exhaustion and postcontraction muscle ischemia (PC). To accomplish this heart rate (HR), arterial pressure (n=10) and plasma norepinephrine (NE) levels (n=8) were measured in 10 healthy male subjects during HG at 40% …
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The contribution of reorganised motor pathways to recovery of arm and hand function after stroke
… 2. Longitudinal investigation of recovery of voluntary movement of arm and hand after stroke. The relationship between the recovery of hand and arm function in a group of acute stroke patients (n=21) and the presence of short latency contralateral and ipsilateral EMG responses to TMS in four …
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