1,580 research outputs found

    Concurrent training

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    Many sports require a range of physical qualities including strength, power and aerobic capacity for optimal performance. Subsequently, training is likely to contain periods where concurrent development of fitness components is required and will typically be classified into two training categories, endurance and strength training. In order to optimize training, the interaction of these fitness components should be considered as endurance training may interfere with resistance training sessions via conflicting molecular signaling which may blunt optimal muscular development. At present, there is a range of conflicting recommendations in the literature due to the challenges of comparing different training studies and the variables which impact upon the magnitude of adaptation; including volume, intensity, sequencing, rest and concurrent training goals. Most importantly, the overall training stress should be considered to limit cumulative fatigue and minimize the potential negative effect on strength adaptations via dampened hypertrophic responses. Inter-session rest should be maximized wherever possible to reduce the interaction between competing molecular signaling pathways. Where required, strength training should be completed after aerobic endurance training to ensure overnight recovery facilitates strength based adaptations. Overall, optimal planning during concurrent training is a complex interaction between a range of variables where strength and conditioning professionals should be conscious of a range of factors and select a training regime that minimized the interference effect but also fits with their own training logistics

    The effects of complex training on neuromuscular development of the lower limbs in youth netball players

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    Objective: The high prevalence of injury in netball can be associated with intrinsic or extrinsic factors. Female athletes have an increased risk of injury as they enter into maturity due to increased joint laxity and a reduction in neuromuscular control, resulting in altered landing biomechanics and greater knee joint injury risk. This study sought to investigate whether complex training (CT) could improve neuromuscular strength and landing kinematics, thereby reducing injury risk to the knee. Methods: A within subject, repeated measures design was utilised. Ten youth netball academy players (age, 15.3 ± 0.9, years; height, 169.0 ± 7.0, cm; body mass, 62.2 ± 6.9, kg) participated and attended one familiarisation and two testing sessions (pre- and post-intervention). Participants’ were assessed on: countermovement jump (CMJ), landing error score system (LESS), and single leg countermovement jump (SLCMJ) of both limbs. All participants engaged in a 6 week, one day per week, strength training and plyometric intervention for the lower limbs utilising CT. Results: Significant improvements were evidenced for CMJ height (p = 0.001, d = 1.2 “moderate” effect), CMJ peak power output (PPO) (p = 0.001, d = 0.7 “small” effect), LESS (p = 0.002, d = 1.7 “large” effect), and SLCMJ left height (p = 0.01, d = 1.2 “moderate” effect) following the intervention. Conclusion: Performing one CT session a week over 6 weeks enhanced kinematics and performance of jumping activities both bilaterally and unilaterally, it also brought about reductions in asymmetries in young female athletes

    El polémico Salmón invasor

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    El salmón Chinook invadió en pocos años todas las cuencas importantes de Patagonia. Revisamos los potenciales efectos biológicos y sociales, describiendo lo que sucede con los usuarios del río De Las Vueltas y habitantes de El Chaltén. Como reflejan los resultados de la encuesta, cada perfil de usuario posee un interés distinto y sólo a través de procesosparticipativos y democráticos entre las instituciones y los usuarios, se podrán tomar decisiones de manejo que acuerden con los objetivos consensuados por la mayoría. Mientras ello no suceda, esta nueva pesquería e invasión biológica, como tantas otras, será un punto de conflicto entre los usuarios de nuestros valiosos ríos y lagos patagónicos.Fil: Ciancio, Javier E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Aigo, Juana del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Clarke, Rodrigo R.. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Flikke, Rune. University of Oslo; Norueg

    Self-consistent scattering description of transport in normal-superconductor structures

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    We present a scattering description of transport in several normal-superconductor structures. We show that the related requirements of self-consistency and current conservation introduce qualitative changes in the transport behavior when the current in the superconductor is not negligible. The energy thresholds for quasiparticle propagation in the superconductor are sensitive to the existence of condensate flow (vs0v_s\neq 0). This dependence is responsible for a rich variety of transport regimes, including a voltage range in which only Andreev transmission is possible at the interfaces, and a state of gapless superconductivity which may survive up to high voltages if temperature is low. The two main effects of current conservation are a shift towards lower voltages of the first peak in the differential conductance and an enhancement of current caused by the greater availability of charge transmitting scattering channels.Comment: 31 pages, 10 PS figures, Latex file, psfig.sty file is added. To appear in Phys. Rev. B (Jan 97

    Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998

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    Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997–1998. The methods used varied from species diversity and species co-occurrence analyses to multivariate ordination methods. Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments

    Combined search for the standard model Higgs boson decaying to a bb pair using the full CDF data set

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    We combine the results of searches for the standard model Higgs boson based on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45/fb. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).Comment: To be published in Phys. Rev. Lett (v2 contains minor updates based on comments from PRL

    Precision Top-Quark Mass Measurements at CDF

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    We present a precision measurement of the top-quark mass using the full sample of Tevatron s=1.96\sqrt{s}=1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb1fb^{-1}. Using a sample of ttˉt\bar{t} candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the WW boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with {\it in situ} calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, \mtop = 172.85 \pm0.71(stat) 0.71 (stat) \pm0.85(syst)GeV/c2. 0.85 (syst) GeV/c^{2}.Comment: submitted to Phys. Rev. Let

    Measurement of the WZWZ Cross Section and Triple Gauge Couplings in ppˉp \bar p Collisions at s=1.96\sqrt{s} = 1.96 TeV

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    This Letter describes the current most precise measurement of the WZWZ production cross section as well as limits on anomalous WWZWWZ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions for the Collider Detector at Fermilab (CDF). WZWZ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb1^{-1} of integrated luminosity), 63 candidate events are observed with the expected background contributing 8±18 \pm 1 events. The measured total cross section σ(ppˉWZ)=3.930.53+0.60(stat)0.46+0.59(syst)\sigma (p \bar p \to WZ) = 3.93_{-0.53}^{+0.60}(\text{stat})_{-0.46}^{+0.59}(\text{syst}) pb is in good agreement with the standard model prediction of 3.50±0.213.50\pm 0.21. The same sample is used to set limits on anomalous WWZWWZ couplings.Comment: Resubmission to PRD-RC after acceptance (27 July 2012

    Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

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    The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure

    Observation of Exclusive Gamma Gamma Production in p pbar Collisions at sqrt{s}=1.96 TeV

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    We have observed exclusive \gamma\gamma production in proton-antiproton collisions at \sqrt{s}=1.96 TeV, using data from 1.11 \pm 0.07 fb^{-1} integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E_T > 2.5 GeV and pseudorapidity |\eta| < 1.0, with no other particles detected in -7.4 < \eta < +7.4. The two showers have similar E_T and azimuthal angle separation \Delta\phi \sim \pi; 34 events have two charged particle tracks, consistent with the QED process p \bar{p} to p + e^+e^- + \bar{p} by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive \pi^0\pi^0 is consistent with zero and is < 15 at 95% C.L. The cross section for p\bar{p} to p+\gamma\gamma+\bar{p} with |\eta(\gamma)| < 1.0 and E_T(\gamma) > 2.5$ GeV is 2.48^{+0.40}_{-0.35}(stat)^{+0.40}_{-0.51}(syst) pb.Comment: 7 pages, 4 figure
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