1,082 research outputs found

    Anthropometric and Performance Characteristics of Elite Hurling Players

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    The purpose of the present study was to examine variations in the anthropometric and performance characteristics of elite hurling players in relation to playing position. Forty-one male, elite intercounty hurlers (25 ± 4 years), 4 goalkeepers, 8 full-backs, 8 halfback, 6 midfielders, 8 half-forwards and 7 full-forwards underwent measurements of standard anthropometric (stature, body mass, sum of five skinfolds and adipose tissue percentage estimates (%AT)) and performance characteristics (counter-movement jump (CMJ), CMJ peak power, CMJ relative peak power, 5-, 10-, 20-m sprint times and estimated V•O2max) during the later stages of the competitive season. A clear hierarchical anthropometric profile is evident with goalkeepers being the taller (184.3 ± 3.7 m), possessing the highest body mass (88.7 ± 5.7 kg) and adiposity (13.2 ± 3.1 %AT) than their outfield colleagues. Half-backs (47.4 ± 2.4 cm) and half-forwards (50.7 ± 5.9 cm) produced the highest CMJ scores; a similar profile was evident for sprint times. Midfielders (60.1 ± 1.4 mL.kg-1.min-1) exhibited a significantly (p<0.05) greater maximal oxygen uptake than all other playing positions. Differences in the anthropometric and performance characteristics of other playing positions whilst evident were non-significant. This study provides novel data, as it is the first report to present normative anthropometric and performance data for elite hurling players which to date has not been present in the literature. The enhanced maximal oxygen uptake in midfield players is likely due to different performance, technical and tactical demands associated with this position

    Can ultrasound be used to stimulate nerve tissue?

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    BACKGROUND: The stimulation of nerve or cortical tissue by magnetic induction is a relatively new tool for the non-invasive study of the brain and nervous system. Transcranial magnetic stimulation (TMS), for example, has been used for the functional mapping of the motor cortex and may have potential for treating a variety of brain disorders. METHODS AND RESULTS: A new method of stimulating active tissue is proposed by propagating ultrasound in the presence of a magnetic field. Since tissue is conductive, particle motion created by an ultrasonic wave will induce an electric current density generated by Lorentz forces. An analytical derivation is given for the electric field distribution induced by a collimated ultrasonic beam. An example shows that peak electric fields of up to 8 V/m appear to be achievable at the upper range of diagnostic intensities. This field strength is about an order of magnitude lower than fields typically associated with TMS; however, the electric field gradients induced by ultrasound can be quite high (about 60 kV/m(2 )at 4 MHz), which theoretically play a more important role in activation than the field magnitude. The latter value is comparable to TMS-induced gradients. CONCLUSION: The proposed method could be used to locally stimulate active tissue by inducing an electric field in regions where the ultrasound is focused. Potential advantages of this method compared to TMS is that stimulation of cortical tissue could be highly localized as well as achieved at greater depths in the brain than is currently possible with TMS

    Over a millon Creatine Kinase due to a heavy work-out: A case report

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    Rhabdomyolysis induced by exercise is a very well known entity, several cases has been reported in the literature related with strenuous activities, weight lifting, marathon running, overexertion in an untrained person, knee bends, etc. We reported an interesting case of exercise-induced rhabdomyolysis in a 25 year old Hispanic male, after resuming his regular physical activity, with the highest creatine kinase described in the literature, successfully treated with aggressive hydration only and no complications

    Positive words carry less information than negative words

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    We show that the frequency of word use is not only determined by the word length \cite{Zipf1935} and the average information content \cite{Piantadosi2011}, but also by its emotional content. We have analyzed three established lexica of affective word usage in English, German, and Spanish, to verify that these lexica have a neutral, unbiased, emotional content. Taking into account the frequency of word usage, we find that words with a positive emotional content are more frequently used. This lends support to Pollyanna hypothesis \cite{Boucher1969} that there should be a positive bias in human expression. We also find that negative words contain more information than positive words, as the informativeness of a word increases uniformly with its valence decrease. Our findings support earlier conjectures about (i) the relation between word frequency and information content, and (ii) the impact of positive emotions on communication and social links.Comment: 16 pages, 3 figures, 3 table

    Ultrasonic Nondestructive Evaluation Using Laser Transducers

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    A program is described which employs lasers for ultrasonic NDE. A high-power laser is used to generate a brief sound pulse in the test specimen. A second low-power laser then measures the response of the specimen to that sound pulse. The response of the specimen is measured by a “Laser Vibrometer.” This is a novel type of heterodyne interferometer which focuses a Helium-Neon laser beam onto the surface of the specimen and measures its displacement. Displacements as small as 2×10-12 meters on a 0.15 sec averaging time can be detected and also displacements of 1.5×l0-9 meters on a 10-MHz bandwidth. The Laser Vibrometer has a well defined frequency response and does not introduce distortion. The sound generating laser is either a pulsed carbon dioxide TEA laser or a YAG laser. The peak power exceeds 10 M watt. Two mechanisms for generating the sound are discussed. The thermoelastic mechanism relies on the thermal expansion of the surface, causing it to move. The reaction to this causes a pressure pulse in the specimen. Another mechanism allows a small amount of the surface to be ablated and the reaction to this causes a substantial pressure pulse in the specimen. Both laser beams can be scanned over the surface of the specimen by a microprocessor controlled mirror. The microprocessor generates a raster scan of arbitrary size, number of lines, step size and speed. Eventually this technique will allow the inspection of complex specimens without direct contact. This will eliminate the tedium and contact reliability problems associated with conventional piezo-ceramic NDE

    Impact of gastroesophageal reflux disease on work absenteeism, presenteeism and productivity in daily life: a European observational study

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    <p>Abstract</p> <p>Background</p> <p>The RANGE (<it>R</it>etrospective <it>AN</it>alysis of <it>G</it>astro<it>E</it>sophageal reflux disease [GERD]) study assessed differences among patients consulting a primary care physician due to GERD-related reasons in terms of: symptoms, diagnosis and management, response to treatment, and effects on productivity, costs and health-related quality of life. This subanalysis of RANGE determined the impact of GERD on productivity in work and daily life.</p> <p>Methods</p> <p>RANGE was conducted at 134 primary care sites across six European countries (Germany, Greece, Norway, Spain, Sweden and the UK). All subjects (aged ≥18 years) who consulted with their primary care physician over a 4-month identification period were screened retrospectively, and those consulting at least once for GERD-related reasons were identified (index visit). From this population, a random sample was selected to enter the study and attended a follow-up appointment, during which the impact of GERD on productivity while working (absenteeism and presenteeism) and in daily life was evaluated using the self-reported Work Productivity and Activity Impairment Questionnaire for patients with GERD (WPAI-GERD).</p> <p>Results</p> <p>Overall, 373,610 subjects consulted with their primary care physician over the 4-month identification period, 12,815 for GERD-related reasons (3.4%); 2678 randomly selected patients attended the follow-up appointment. Average absenteeism due to GERD was highest in Germany (3.2 hours/week) and lowest in the UK (0.4 hours/week), with an average of up to 6.7 additional hours/week lost due to presenteeism in Norway. The average monetary impact of GERD-related work absenteeism and presenteeism were substantial in all countries (from €55/week per employed patient in the UK to €273/patient in Sweden). Reductions in productivity in daily life of up to 26% were observed across the European countries.</p> <p>Conclusion</p> <p>GERD places a significant burden on primary care patients, in terms of work absenteeism and presenteeism and in daily life. The resulting costs to the local economy may be substantial. Improved management of GERD could be expected to lessen the impact of GERD on productivity and reduce costs.</p

    Avaliação da intensidade do treinamento técnico-tático e da fadiga causada em jogadores de futebol da categoria sub-20

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    Resumo Visto que o calendário atual do futebol não disponibiliza um tempo hábil para a devida recuperação dos atletas, fadiga e recuperação têm sido amplamente estudadas por pesquisadores. O que levou ao surgimento de alguns instrumentos com o propósito de fornecer informações e dar suporte aos profissionais visando a alta performance. O objetivo deste estudo foi analisar a intensidade do Treinamento Técnico-tático e a fadiga causada em jogadores de futebol da categoria sub-20, através do desempenho em testes de salto vertical e horizontal e da percepção subjetiva de esforço da sessão (PSE da sessão). Os jogadores (n = 25) realizaram o salto vertical contra movimento (SCM) e horizontal (SH), antes e após a uma sessão de Treinamento Técnico-tático (TTT), sendo a intensidade avaliada pela Escala de Borg (CR 10). O SCM não apresentou diferença significativa (p > 0,05), enquanto que o SH foi maior no Pós-TTT em relação ao Pré-TTT (p = 0,02). Quanto a PSE da sessão, 92% dos jogadores classificaram a intensidade do TTT como sendo de fácil à moderada. Os resultados deste estudo indicam que o TTT de baixa intensidade não compromete a potência nos testes de salto vertical e horizontal. Sugere-se que além de proporcionar a operacionalização dos padrões de comportamento táticos coletivos, o TTT de baixa intensidade possa ser utilizado em treinamentos de caráter regenerativo ou em momentos que o calendário esportivo não possibilite a recuperação completa dos jogadores

    Effect of Contour Shape of Nervous System Electromagnetic Stimulation Coils on the Induced Electrical Field Distribution

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    BACKGROUND: Electromagnetic stimulation of the nervous system has the advantage of reduced discomfort in activating nerves. For brain structures stimulation, it has become a clinically accepted modality. Coil designs usually consider factors such as optimization of induced power, focussing, field shape etc. In this study we are attempting to find the effect of the coil contour shape on the electrical field distribution for magnetic stimulation. METHOD AND RESULTS: We use the maximum of the induced electric field stimulation in the region of interest as the optimization criterion. This choice required the application of the calculus of variation, with the contour perimeter taken as a pre-set condition. Four types of coils are studied and compared: circular, square, triangular and an 'optimally' shaped contour. The latter yields higher values of the induced electrical field in depths up to about 30 mm, but for depths around 100 mm, the circular shape has a slight advantage. The validity of the model results was checked by experimental measurements in a tank with saline solution, where differences of about 12% were found. In view the accuracy limitations of the computational and measurement methods used, such differences are considered acceptable. CONCLUSION: We applied an optimization approach, using the calculus of variation, which allows to obtain a coil contour shape corresponding to a selected criterion. In this case, the optimal contour showed higher intensities for a longer line along the depth-axis. The method allows modifying the induced field structure and focussing the field to a selected zone or line

    The differential hormonal milieu of morning versus evening, may have an impact on muscle hypertrophic potential

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    Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely

    Biological effects of exposure to magnetic resonance imaging: an overview

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    The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited
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