407 research outputs found

    Neither internal nor external nasal dilation improves cycling 20-km time trial performance

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    Objectives: Research is equivocal regarding endurance performance benefits of external nasal dilators, and currently research focusing on internal nasal dilators is non-existent. Both devices are used within competitive cycling. This study examined the influence of external and internal nasal dilation on cycling economy of motion and 20-km time trial performance. Design: The study utilized a randomized, counterbalanced cross-over design. Methods: Fifteen trained cyclists completed three exercise sessions consisting of a 15min standardized warm up and 20-km cycling time trial while wearing either a Breathe RightÂŽ external nasal dilator, TurbineÂŽ internal nasal dilator or no device (control). During the warm up, heart rate, ratings of perceived exertion and dyspnea and expired gases were collected. During the time trial, heart rate, perceived exertion, and dyspnea were collected at 4-km intervals and mean 20-km power output was recorded. Results: No differences were observed for mean 20-km power output between the internal (270. Âą. 45. W) or external dilator (271. Âą. 44. W) and control (272. Âą. 44. W). No differences in the economy of motion were observed throughout the 15-min warm up between conditions. Conclusions: The TurbineÂŽ and Breathe RightÂŽ nasal dilators are ineffective at enhancing 20-km cycling time trial performance

    Influence of age and sex on pacing during Sprint, Olympic, Half-Ironman and Ironman triathlons: Part B

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    The aim of this study was to investigate the influence of biological sex and age on the pacing strategies adopted by non-drafting top triathletes during the cycle and run disciplines of a Sprint, Olympic, half-Ironman and Ironman triathlon. Split times of the top 20% non-elite males (n=468) and females (n=146) were determined using official race transponders and a video capture system for pre-determined sections of the cycle and run disciplines of four triathlon distances. Indices of pacing were calculated to compare between sexes and age-groups. Results of this study indicated that different pacing strategies were adopted between athletes of different age and sex over the various triathlon disciplines and distances. Females were more aggressive during the initial stages of the cycling discipline across all distances (sprint - 2.1% p=0.024; Olympic - 1.6%, p=0.011; half-Ironman- 1.5%, p<0.001; Ironman - 1.7%, p<0.001 higher relative to mean) compare with males. Younger athletes (20-29 y) tend to begin the run faster (2.0 to 3.0% faster than other age-groups, p<0.029) during the sprint, Olympic and half-Ironman triathlons. These results indicate that different pacing strategies are adopted by non-drafting top athletes of different age and sex. Optimal pacing strategies may differ between sex and ages; therefore individuals may need to trial different strategies to develop their own optimal pacing profile for triathlon events of varying distances

    Influence of race distance and biological sex on age-related declines in triathlon performance: Part A

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    This study examined the effect of biological sex and race distance on the age-related declines in swimming, cycling, running and overall performances of the sprint, Olympic, Half-Ironman and Ironman triathlons. Individual discipline and overall performance time of the top 20% non-elite males (n=468) and females (n=146) were compared by categorizing into four 10-year age-groups (20-29, 30-39, 40-49, 50+ years) and normalising to the mean performance time of the fastest age-group for each race. An earlier, larger and faster rate of decline (p=0.01) in performance with ageing was observed in females (≥30 years, 9.3%, 3.0% per decade respectively) and males (≥40 years, 5.9%, 2.2% per decade, respectively) for the longer events (half-Ironman and Ironman) compared with the shorter distances (sprint and Olympic, ≥50 years for both sexes). A greater magnitude of decline was observed in swimming for both sexes, especially in the longer events, when compared with cycling and running (12.8%, 5.6%, 9.3% for females, 9.4%, 3.7%, 7.3% for males, in the swim, cycle and run disciplines, respectively). These results indicate that both race distance and biological sex influence the age-related decline in triathlon performance and could aid athletes in optimising training programs to attenuate the age-related declines in performance across different disciplines and distances. Specifically, older athletes may benefit from greater emphasis on swim training and factors that may influence performance during longer distance triathlons

    Load-velocity relationships and predicted maximal strength: A systematic review of the validity and reliability of current methods

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    Maximal strength can be predicted from the load-velocity relationship (LVR), although it is important to understand methodological approaches which ensure the validity and reliability of these strength predictions. The aim of this systematic review was to determine factors which influence the validity of maximal strength predictions from the LVR, and secondarily to highlight the effects of these factors on the reliability of predictions. A search strategy was developed and implemented in PubMed, Scopus, Web of Science and CINAHL databases. Rayyan software was used to screen titles, abstracts, and full texts to determine their inclusion/eligibility. Eligible studies compared direct assessments of one-repetition maximum (1RM) with predictions performed using the LVR and reported prediction validity. Validity was extracted and represented graphically via effect size forest plots. Twenty-five eligible studies were included and comprised of a total of 842 participants, three different 1RM prediction methods, 16 different exercises, and 12 different velocity monitoring devices. Four primary factors appear relevant to the efficacy of predicting 1RM: the number of loads used, the exercise examined, the velocity metric used, and the velocity monitoring device. Additionally, the specific loads, provision of velocity feedback, use of lifting straps and regression model used may require further consideration

    Resistance training enhances delayed memory in healthy middle-aged and older adults: A randomised controlled trial

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    Objectives High-intensity exercise is a potential therapeutic tool to postpone or prevent the onset of cognitive decline. However, there is a lack of sufficient evidence regarding the longitudinal effects of structured resistance training on cognitive function in healthy adults. The purpose of this study was to investigate the effect of two ecologically valid, intense 12-week resistance training programs on cognitive function in late middle-aged adults. Design Single-site parallel randomised controlled trial at the Department of Exercise Science strength and conditioning laboratory. Groups allocated by minimisation randomisation. Methods Forty-five healthy adults (age range = 41-69 years) were enrolled and randomised into A.) high-load, long rest resistance training (n = 14), or B.) moderate-load, short rest resistance training (n = 15) twice per week for 12 weeks, or a non-exercising control (n = 16). Follow-up within 7 days. Data were collected September 2016-December 2017. Cognitive function assessed using the CogState computerised battery. Assessors were blinded to participant group allocation. Secondary outcomes were maximal muscle strength and body composition. Results Forty-four participants were analysed in 2018. Delayed verbal memory performance was improved (p = 0.02) in resistance training groups (g = 0.67-0.79) when compared to the control group, with no differences between training groups. Likewise, increases in maximal muscle strength were observed (p < 0.01) in resistance training groups when compared to the control group, with no differences between training groups. No differences in body composition were observed. There were no adverse events or side-effects of the intervention. Conclusions 12 weeks of intense resistance training improves delayed verbal memory irrespective of training design (i.e., high-load vs. moderate-load)

    A randomized controlled trial of high-intensity exercise and executive functioning in cognitively normal older adults

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    Background There is a paucity of interventional research that systematically assesses the role of exercise intensity and cardiorespiratory fitness, and their relationship with executive function in older adults. To address this limitation, we have examined the effect of a systematically manipulated exercise intervention on executive function. Methods Ninety-nine cognitively normal participants (age = 69.10 ± 5.2 years; n = 54 female) were randomized into either a high-intensity cycle-based exercise, moderate-intensity cycle-based exercise, or no-intervention control group. All participants underwent neuropsychological testing and fitness assessment at baseline (preintervention), 6-month follow-up (postintervention), and 12-month postintervention. Executive function was measured comprehensively, including measures of each subdomain: Shifting, Updating/ Working Memory, Inhibition, Verbal Generativity, and Nonverbal Reasoning. Cardiorespiratory fitness was measured by analysis of peak aerobic capacity; VO2peak. Results First, the exercise intervention was found to increase cardiorespiratory fitness (VO2peak) in the intervention groups, in comparison to the control group (F =10.40, p≤0.01). However, the authors failed to find mean differences in executive function scores between the high-intensity, moderate intensity, or inactive control group. On the basis of change scores, cardiorespiratory fitness was found to associate positively with the executive function (EF) subdomains of Updating/Working Memory (β = 0.37, p = 0.01, r = 0.34) and Verbal Generativity (β = 0.30, p = 0.03, r = 0.28) for intervention, but not control participants. Conclusion At the aggregate level, the authors failed to find evidence that 6-months of high-intensity aerobic exercise improves EF in older adults. However, it remains possible that individual differences in experimentally induced changes in cardiorespiratory fitness may be associated with changes in Updating/ Working Memory and Verbal Generativity

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

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    The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

    Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

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    A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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