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Results 301 - 350 of 1190
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Giske Liv - - 2008
The pathogenesis of widespread pain and fibromyalgia (FM) is unknown. Altered responses from the hypothalamus-pituitary-adrenal axis, sympathetic nervous system and muscular system have been suggested as being of importance. The present study was undertaken to determine: (i) whether the sympathoadrenal response to repetitive isometric contractions until exhaustion is altered in ...
Streckis Vytautas - - 2007
Performance in high-intensity exercise is dependent on the ability to activate motor units. The main aim of this study was to test the hypothesis that adult men and women (age 19-27 years) are able to maintain higher levels of voluntary activation (VA) in knee extensor muscles than boys and girls ...
Schneider Carole M - - 2007
This investigation determined the cardiopulmonary function and fatigue alterations in male cancer survivors during treatment as well as following treatment utilizing similar exercise assessment protocols and individualized, prescriptive exercise interventions. The study included 45 male cancer survivors that were referred by local oncologists. Following a comprehensive screening and physical examination, ...
Vangelakoudi A - - 2007
Laser sailors have to tolerate fatiguing contractions of the lower-body muscles for prolonged periods. The aims of the present study were (1) to evaluate the difference between top-ranked and club sailors, in their capacity to resist fatigue during sustained isometric and maximal power exercise, and (2) to examine the relationships ...
Spurway Neil C - - 2007
The literature indicates that the heart rate of a planing-dinghy sailor, in winds of 4 - 5 m . s(-1), is in the range seen in aerobic athletes, yet oxygen consumption (VO(2)) is roughly half that of the same individual cycling at that heart rate. Thus, although upper-body dynamic activity ...
Batista Mauro A B - - 2007
Postactivation potentiation (PAP) is defined as a short-term increase in voluntary muscle activation following a previous conditioning activity (CA). Controversy about PAP is mostly attributed to the characteristics of the CA and the training status of the subjects. While some studies have found that PAP can be induced by series ...
Meeusen Romain - - 2007
It is clear that the cause of fatigue is complex, influenced by both events occurring in the periphery and the central nervous system (CNS). It has been suggested that exercise-induced changes in serotonin (5-HT), dopamine (DA), and noradrenaline (NA) concentrations contribute to the onset of fatigue during prolonged exercise. Serotonin ...
Damon Bruce M BM Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232, USA. - - 2007
The time course of exercise-induced T(2)-weighted signal intensity (SI) changes contains an initial rise, early dip, and secondary rise. The purposes of this study were to test the hypothesis that the secondary rise occurs earlier during more intense contractions, and to determine the contribution of BOLD contrast to the SI ...
Yoshiuchi Kazuhiro - - 2007
Patients with chronic fatigue syndrome (CFS) report substantial symptom worsening after exercise. However, the time course over which this develops has not been explored. Therefore, the objective of this study was to investigate the influence of exercise on subjective symptoms and on cognitive function in CFS patients in natural settings ...
Eston Roger - - 2007
This study assessed the relationship between the rate of change of the rating of perceived exertion (RPE), physiological activity, and time to volitional exhaustion. After completing a graded exercise test, 10 participants cycled at a constant load equating to 75% of peak oxygen uptake (V O(2)peak) to exhaustion. Participants performed ...
Girard Olivier - - 2008
The time course of alteration in neuromuscular function of the knee extensor muscles was characterized during a prolonged intermittent exercise. Maximal voluntary contraction (MVC) and surface EMG activity of both vastii were measured during brief interruptions before (T(0)), during (30, 60, 90, 120, 150 and 180min: T(30), T(60), T(90), T(120), ...
Wyller Vegard Bruun - - 2007
OBJECTIVES: Chronic fatigue syndrome is a common and disabling disease of unknown etiology. Accumulating evidence indicates dysfunction of the autonomic nervous system. To further explore the pathophysiology of chronic fatigue syndrome, we investigated thermoregulatory responses dependent on catecholaminergic effector systems in adolescent patients with chronic fatigue syndrome. PATIENTS AND METHODS: ...
Powell David M C - - 2007
INTRODUCTION: There is little research on what factors are associated with fatigue in short-haul pilots. The aim was to investigate how length of duty, number of sectors, time of day, and departure airport affect fatigue levels in short-haul operations. METHODS: Pilots completed Samn-Perelli fatigue ratings prior to descent at the ...
Khedr E M - - 2007
There is lack of clarity in the literature over whether patients with Parkinson's disease (PD) show the same post-exercise depression of corticospinal excitability as is usually observed in healthy control. This study set out to resolve the problem. Ten patients with idiopathic PD and 10 age-matched controls were included in ...
Mulder E R - - 2009
The aim of the present study was to assess the time course and the origin of adaptations in neuromuscular function as a consequence of prolonged bed rest with or without countermeasure. Twenty healthy males volunteered to participate in the present study and were randomly assigned to either an inactive control ...
van Engelen E - - 2007
The cervix must regain its normal diameter after parturition. Until now, little has been known about the pattern of cervical closure and the possible influences of myometrial and cervical contractions in this process. We continuously measured the cervical diameter with ultrasound cervimetry during the first 48h after calving in six ...
Benwell Nicola M NM Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, WA 6009, - - 2007
The aim of this study was to determine whether there were significant changes in the time course of the functional magnetic resonance imaging (fMRI) signal in motor and non-motor regions of both cerebral hemispheres during a unilateral fatiguing exercise of the hand. Twelve subjects performed a submaximal (30%) intermittent fatiguing ...
Mika Anna - - 2007
OBJECTIVE: The objective of this study was to assess the influence of different relaxation modes: stretching (ST), active recovery (AR), and passive recovery (PR) on muscle relaxation after dynamic exercise of the quadriceps femoris. DESIGN: Ten healthy male volunteers between 24 and 38 yrs of age participated in this study. ...
Rouffet David M - - 2008
The value of electromyography (EMG) is sensitive to many physiological and non-physiological factors. The purpose of the present study was to determine if the torque-velocity test (T-V) can be used to normalize EMG signals into a framework of biological significance. Peak EMG amplitude of gluteus maximus (GMAX), vastus lateralis (VL), ...
Soller Babs R - - 2007
Oxygen and acid-base status during exercise is well established for the lungs, large arteries and veins. However, values for these parameters in exercising muscle are less frequently reported. In this study we examined the relationship between intramuscular PO(2), pH, PCO(2) and the comparable venous values during rhythmic isometric handgrip exercise ...
Clark Brian C - - 2007
OBJECTIVE: To investigate the influence of fatigue on phasic muscle-activation patterns during dynamic trunk extension exercise. DESIGN: Fifteen healthy volunteers performed dynamic trunk-extension exercise through a 30-degree range-of-motion (ROM) exercise to task failure at an intensity of 50% of maximum. Electromyography (EMG) signals were recorded unilaterally from the lumbar extensor, ...
Thompson Benjamin C - - 2007
Previous studies suggest that women experience less vascular occlusion than men when generating the same relative contractile force. This study examined forearm blood flow (FBF) in women and men during isometric handgrip exercise requiring the same relative force. Thirty-eight subjects [20 women and 18 men, 22.8 +/- 0.6 yrs old ...
Jones A S - - 2007
Self-healing polymers, based on microencapsulated dicyclopentadiene and Grubbs' catalyst embedded in the polymer matrix, are capable of responding to propagating fatigue cracks by autonomic processes that lead to higher endurance limits and life extension, or even the complete arrest of the crack growth. The amount of fatigue-life extension depends on ...
Kruger Eric S ES Motor Control Laboratory, School of Physical Therapy and Rehabilitation Science, University of Montana, Missoula, MT 59812, - - 2007
The effect of muscle fatigue on error compensation strategies during multi-finger ramp force production tasks was investigated. Thirteen young, healthy subjects were instructed to produce a total force with four fingers of the right hand to accurately match a visually displayed template. The template consisted of a 3-s waiting period, ...
Ounsi Hani F - - 2007
The resistance of ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium rotary instruments to cyclic fatigue was examined after their initial use in straight or curved canals in vivo. These instruments were rotated freely inside a steel phantom until separation. The number of rotations before failure and the lengths of the separated ...
Shushakov Vladimir - - 2007
The relationships between extracellular potassium elevation and EMG variables in relation to muscle fatigue were investigated during handgrip exercise in humans. Acid-base state, lactate, potassium ([K+](v)) and sodium in venous plasma, as well as variables of surface voluntary and evoked (M-wave) EMG were determined during repeated dynamic (DE) and static ...
Stewart R D - - 2007
To determine if exercise-induced depressions in neuromuscular function are altered with oral glucose supplementation, 15 untrained participants (Vo2 peak = 45 +/- 2 ml x kg(-1) x min(-1), mean +/- SE) performed prolonged cycle exercise at approximately 60% Vo2 peak on two occasions: without glucose supplementation (NG) and with oral ...
Green H J - - 2007
Regulation of maximal Na(+)-K(+)-ATPase activity in vastus lateralis muscle was investigated in response to prolonged exercise with (G) and without (NG) oral glucose supplements. Fifteen untrained volunteers (14 males and 1 female) with a peak aerobic power (Vo(2)(peak)) of 44.8 +/- 1.9 ml.kg(-1).min(-1); mean +/- SE cycled at approximately 57% ...
Dayioglu Emel - - 2007
The authors investigate the effect of bumetan ide, an inhibitor of NKCC1 and a loop diuretic, on the tone of human umbilical artery (HUA). Rings of HUA (n = 35) from vaginal deliveries were suspended for isometric tension recordings in organ baths. Cumulative concentration-response curves to serotonin, histamine, and KCl ...
Bove Marco - - 2007
The effect of a strenuous treadmill exercise on body stability and the mechanisms associated with it have been studied with two different experimental protocols. The former investigation was based on stabilometric and metabolic measurements performed in basal condition and after a strenuous treadmill exercise whilst the latter dealt with the ...
Meisner Joshua K - - 2007
Although behavior of lymphatic vessels is analogous to that of ventricles, which completely relax between contractions, and blood vessels, which maintain a tonic constriction, the mixture of contractile properties can yield behavior unique to lymphatic vessels. In particular, because of their limited refractory period and slow rate of relaxation, lymphatic ...
Peters Ove A - - 2007
This study investigated the effect of immersion in sodium hypochlorite (NaOCl) on torque and fatigue resistance of two nickel-titanium files. Size 25 .04 ProFile and RaCe files were immersed in 5.25% NaOCl for 1 or 2 hours at temperatures of 21 degrees C and 60 degrees C. Torque and angle ...
Holmberg Anna - - 2007
Spontaneous regular gut motility in zebrafish begins around 4 days post fertilisation (d.p.f.) and is modulated by release of acetylcholine and nitric oxide. The role of intrinsic or extrinsic innervation for initiating and propagating the spontaneous contractions, however, is not well understood. By creating spatiotemporal maps, we could examine spontaneous ...
Regueme S C - - 2007
Minor cross-over effects of unilateral muscle fatigue have been reported after isometric exercises. The present study re-examined this possibility after an exhaustive stretch-shortening cycle (SSC)-type exercise. Twenty-five subjects performed on a sledge apparatus a unilateral exhaustive rebound exercise involving mostly the triceps surae muscle group. Ipsilateral vs contralateral fatigue effects ...
Yildiz Oguzhan - - 2007
OBJECTIVE: To investigate the direct effects of dexmedetomidine (DEX) on isolated human internal mammary artery (IMA). DESIGN: In vitro experimental study. SETTING: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Gulhane School of Medicine, Ankara, Turkey. PARTICIPANTS: IMA segments were obtained from 18 patients undergoing coronary artery bypass surgery. INTERVENTIONS: The response ...
Evetovich Tammy K - - 2007
The purpose of the study was to examine the potential for using the mechanomyographic (MMG) signal as a biofeedback method to enhance muscular relaxation and to improve performance during forearm flexion repetitions to fatigue. Twelve adult (mean +/- SD; age: 22.0 +/- 1.1 years) moderately trained subjects (weight: 82.3 +/- ...
Smith J Chadwick - - 2007
The purpose of this investigation was to evaluate the role of an elevated regulatory myosin light-chain (RLC) phosphorylation on subsequent postactivation potentiation induced by a 10-second maximum voluntary contraction (MVC). With the use of a repeated measures design, data were collected from 11 recreationally active men who performed an explosive ...
Kuitunen S - - 2007
The present study examined the effects of muscle activity modulation on leg stiffness during an exhaustive stretch-shortening cycle (SSC) exercise in eight male subjects. Reaction force, electromyography (EMG) of the soleus (Sol), gastrocnemius (Ga) and vastus lateralis (VL) muscles and sledge seat position were recorded during the SSC exercise, consisting ...
de Oliveira Anamaria Siriani - - 2008
The purpose of this study was to compare SEMG activities during axial load exercises on a stable base of support and on a medicine ball (relatively unstable). Twelve healthy male volunteers were tested (x=23+/-7 y). Surface EMG was recorded from the biceps brachii, anterior deltoid, clavicular portion of pectoralis major, ...
Wyller, Vegard Bruun
Chronic fatigue syndrome (CFS) is a disabling disease with unknown pathophysiology, but recent evidence suggests autonomic dysfunction. We have therefore explored cardiovascular and thermoregulatory autonomic responses. A consecutive sample of 15/27 CFS patients 12-18 years old and a volunteer sample of 33/57 healthy controls having equal distribution of gender and ...
Garrandes Frédéric - - 2007
PURPOSE: This study examined the effects of training background on the relationship between the neuromuscular fatigue profile and maximal voluntary torque production in isometric, concentric, and eccentric contraction modes. METHODS: Before and after three sets of 31 isokinetic concentric knee extensions at 60 degrees .s(-1), voluntary and electrically induced contractions ...
Evans William J - - 2007
This work summarizes our knowledge of the physiological basis of fatigue and the effects of exercise and pharmacological interventions on fatigue. Fatigue may be defined as physical and/or mental weariness resulting from exertion, that is, an inability to continue exercise at the same intensity with a resultant deterioration in performance. ...
Oliveira A S C - - 2007
Muscle fatigue can be a limiting factor to determine index as the electromyographic fatigue threshold (EMGFT) due the alterations in motivation and disconfots. This way, the purpose of this study was to identify the right biceps brachii and left biceps brachii obtained from repetitive elbow flexions at each 100% of ...
Noakes Timothy D - - 2007
Two popular models hold that performance during exercise is limited by chemical factors acting either in the exercising muscles or in the brain producing either 'peripheral' or 'central' fatigue, respectively. A common feature of both models is that neither allows humans to 'anticipate' what will happen in the future and ...
Nybo Lars - - 2007
This review deals with new aspects of exercise in the heat as a challenge that not only influences the locomotive and cardiovascular systems, but also affects the brain. Activation of the brain during such exercise is manifested in the lowering of the cerebral glucose to oxygen uptake ratio, the elevated ...
Nijs Jo - - 2007
This study examined whether a linear exercise stress-testing protocol generated different peak exercise performance variables than a stepwise exercise testing protocol in patients with chronic fatigue syndrome (CFS). We conducted a comparative study with patients randomly allocated to one of two exercise testing protocols. Twenty-eight women with CFS completed two ...
Nago Takeshi - - 2007
Muscle training exercises are needed for muscular endurance during spaceflight. This study was designed to investigate effects of volitional contraction against applied electrical stimulation on the muscular endurance of the proximal upper extremity. Thirteen healthy sedentary men were allocated into two groups. One group participated in a hybrid (HYB) exercise ...
Shevchuk Nikolai A - - 2007
Physiological fatigue can be defined as a reduction in the force output and/or energy-generating capacity of skeletal muscle after exertion, which may manifest itself as an inability to continue exercise or usual activities at the same intensity. A typical example of a fatigue-related disorder is chronic fatigue syndrome (CFS), a ...
Kiryu Tohru T Graduate School of Science and Technology, Center for Transdisciplinary Research, Niigata University, Nishi-Ku, Niigata, 950-2181 Japan. - - 2007
For health promotion and motor rehabilitation, controlling muscular fatigue on-site is important during exercise sessions. We have developed a ubiquitous wearable unit with a Linux board and tried to apply it to the control of a torque-assisted bicycle with a biosignal-based fuzzy system designed for a cycle ergometer. The results ...
Minogue Conor M CM Biomedical Research Ltd and the UCD School of Electrical, Electronic and Mechanical Engineering, University College Dublin, Dublin 4, Ireland. - - 2007
Electrical Stimulation (ES) is increasingly being considered as a means to improve cardio-pulmonary performance in patients with reduced exercise capacity. This short review considers the ES signal parameters and protocols used in studies that have included a measurement of oxygen uptake during the session. It suggests that the tetanic signal ...
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