240 research outputs found

    Effect of two-weeks endurance training wearing additional clothing in a temperate outdoor environment on performance and physiology in the heat

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    This investigation assessed performance, physiological and perceptual responses to wearing additional clothing during endurance training for two-weeks in temperate environments, to determine if this approach could be used as a practical, alternative, heat acclimation strategy for athletes. Fifteen trained male triathletes assigned to performance-matched groups completed a two-week unsupervised endurance cycling and running program in either (i) shorts and a short sleeve top (CON; n = 8) or (ii) additional clothing of full-length pants, a “winter” jacket and gloves made from nylon, polyurethane and polyester (AC; n = 7). Participants completed three separate (i.e. familiarisation, pre-program and post-program), identical, pre-loaded cycling time-trials (20 min at 180 W followed by a 40 min self-paced time trial) in 32.5 ± 0.1°C and 55 ± 6% RH. Core and skin temperatures, heart rate, sweat rate, perceived exertion, thermal sensation and thermal comfort were measured across the pre-loaded time trials, and heart rate and thermal sensation were measured across the training program. All of the participants recorded in their diaries that they completed all of the programmed training sessions in the required attire. Mean thermal sensation was most likely hotter in AC (5.5 ± 0.4 AU) compared to CON (4.4 ± 0.4 AU; ES = 1.61, ± 0.68) during the training sessions. However, follow up tests revealed no physiological or perceptual signs of heat acclimation, and the change in time-trial performance from pre-post between groups was trivial (CON: −3.5 ± 12.0 W, AC: −4.1 ± 9.6 W; difference = -0.7%, ± 5.4%). Training in additional clothing for two-weeks in a temperate environment was not an effective heat acclimation strategy for triathletes

    Pre-exercise carbohydrate or protein ingestion influences substrate oxidation but not performance or hunger compared with cycling in the fasted state

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    Nutritional intake can influence exercise metabolism and performance, but there is a lack of research comparing protein-rich pre-exercise meals with endurance exercise performed both in the fasted state and following a carbohydrate-rich breakfast. The purpose of this study was to determine the effects of three pre-exercise nutrition strategies on metabolism and exercise capacity during cycling. On three occasions, seventeen trained male cyclists (VO2peak 62.2 ± 5.8 mL·kg−1·min−1, 31.2 ± 12.4 years, 74.8 ± 9.6 kg) performed twenty minutes of submaximal cycling (4 × 5 min stages at 60%, 80%, and 100% of ventilatory threshold (VT), and 20% of the difference between power at the VT and peak power), followed by 3 × 3 min intervals at 80% peak aerobic power and 3 × 3 min intervals at maximal effort, 30 min after consuming a carbohydrate-rich meal (CARB; 1 g/kg CHO), a protein-rich meal (PROTEIN; 0.45 g/kg protein + 0.24 g/kg fat), or water (FASTED), in a randomized and counter-balanced order. Fat oxidation was lower for CARB compared with FASTED at and below the VT, and compared with PROTEIN at 60% VT. There were no differences between trials for average power during high-intensity intervals (367 ± 51 W, p = 0.516). Oxidative stress (F2-Isoprostanes), perceived exertion, and hunger were not different between trials. Overall, exercising in the overnight-fasted state increased fat oxidation during submaximal exercise compared with exercise following a CHO-rich breakfast, and pre-exercise protein ingestion allowed similarly high levels of fat oxidation. There were no differences in perceived exertion, hunger, or performance, and we provide novel data showing no influence of pre-exercise nutrition ingestion on exercise-induced oxidative stress

    Very low-carbohydrate high-fat diet improves risk markers for cardiometabolic health more than exercise in men and women with overfat constitution: Secondary analysis of a randomized controlled clinical trial

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    Purpose: This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12-weeks on cardiometabolic risk factors in individuals with overfat constitution. Methods: Ninety-one participants out of 109 completed the study. The participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Fasting plasma samples were collected before the intervention and after 4 and 12 weeks. The analyzed outcomes included complete blood count, glucose, insulin, glycated hemoglobin, triglycerides (TG), cholesterol, high- and low-density lipoprotein (HDL-C and LDL-C), lipoprotein(a), adiponectin (Adpn), leptin (Lep), tumor necrosis factor alpha (TNF-alpha), other interleukins (hs-IL-6, IL-1 beta, and IL-10), and IL-1RA. The homeostasis model assessment of insulin resistance (HOMA-IR), Adpn/Lep ratio, TG/HDL-C ratio, and TyG index were calculated and analyzed. Blood pressure was measured before the intervention, after 4, 8, and 12 weeks (: NCT03934476). Results: Absolute changes in HOMA-IR, Adpn/Lep ratio, LDL-C, and diastolic blood pressure after 12 weeks differed by study groups (p < 0.05). The most pronounced changes were revealed in the VLCHF (& UDelta;M [95% CI]; HOMA-IR: -0.75 [-1.13; -0.55]; Adpn/Lep: 9.34 [6.33; 37.39]; LDL-C: 0.06 [-0.12; 0.50] mmol/l) and VLCHF+HIIT (HOMA-IR: -0.44 [-1.14; 0.12]; Adpn/Lep: 4.26 [2.24; 13.16]; LDL-C: 0.25 [-0.04; 0.50] mmol/l) groups. Conclusions: A 12-week VLCHF diet intervention in individuals with overfat constitution is effective for favorable changes in HOMA-IR (compared to HIIT), Adpn/Lep ratio, and diastolic blood pressure. HIIT, or HIIT combined with the VLCHF diet, had no additional benefits for the analyzed variables. No adverse side effects were observed.Web of Science9art. no. 86769

    Measurement of the CKM angle γ\gamma in the B0→DK∗0B^0 \to DK^{*0} channel using self-conjugate D→KS0h+h−D \to K_S^0 h^+ h^- decays

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    A model-independent study of CP violation in B0→DK∗0B^0 \to DK^{*0} decays is presented using data corresponding to an integrated luminosity of 9fb−1^{-1} collected by the LHCb experiment at centre-of-mass energies of s=7, 8\sqrt{s}=7, \, 8 and 1313TeV. The CKM angle Îł\gamma is determined by examining the distributions of signal decays in phase-space bins of the self-conjugate D→KS0h+h−D \to K_S^0 h^+ h^- decays, where h=π,Kh = \pi, K. Observables related to CP violation are measured and the angle Îł\gamma is determined to be Îł=(49−18+23)∘\gamma=(49^{+ 23}_{-18})^\circ. Measurements of the amplitude ratio and strong-phase difference between the favoured and suppressed B0B^0 decays are also presented.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-009.html (LHCb public pages

    Study of charmonium decays to KS0KπK^0_S K \pi in the B→(KS0Kπ)KB \to (K^0_S K \pi) K channels

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    A study of the B+→KS0K+K−π+B^+\to K^0_SK^+K^-\pi^+ and B+→KS0K+K+π−B^+\to K^0_SK^+K^+\pi^- decays is performed using proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV at the LHCb experiment. The KS0KπK^0_SK \pi invariant mass spectra from both decay modes reveal a rich content of charmonium resonances. New precise measurements of the ηc\eta_c and ηc(2S)\eta_c(2S) resonance parameters are performed and branching fraction measurements are obtained for B+B^+ decays to ηc\eta_c, J/ψJ/\psi, ηc(2S)\eta_c(2S) and χc1\chi_{c1} resonances. In particular, the first observation and branching fraction measurement of B+→χc0K0π+B^+ \to \chi_{c0} K^0 \pi^+ is reported as well as first measurements of the B+→K0K+K−π+B^+\to K^0K^+K^-\pi^+ and B+→K0K+K+π−B^+\to K^0K^+K^+\pi^- branching fractions. Dalitz plot analyses of ηc→KS0Kπ\eta_c \to K^0_SK\pi and ηc(2S)→KS0Kπ\eta_c(2S) \to K^0_SK\pi decays are performed. A new measurement of the amplitude and phase of the KπK \pi SS-wave as functions of the KπK \pi mass is performed, together with measurements of the K0∗(1430)K^*_0(1430), K0∗(1950)K^*_0(1950) and a0(1700)a_0(1700) parameters. Finally, the branching fractions of χc1\chi_{c1} decays to K∗K^* resonances are also measured.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-051.html (LHCb public pages

    Test of lepton flavour universality using B0→D∗−τ+ΜτB^0 \to D^{*-}\tau^+\nu_{\tau} decays with hadronic τ\tau channels

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    The branching fraction B(B0→D∗−τ+Μτ)\mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau}) is measured relative to that of the normalisation mode B0→D∗−π+π−π+B^0 \to D^{*-}\pi^+\pi^-\pi^+ using hadronic τ+→π+π−π+(π0)Μˉτ\tau^+ \to \pi^+\pi^-\pi^+(\pi^0)\bar{\nu}_{\tau} decays in proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb−1^{-1}. The measured ratio is B(B0→D∗−τ+Μτ)/B(B0→D∗−π+π−π+)=1.70±0.10−0.10+0.11\mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})/\mathcal{B}(B^0 \to D^{*-}\pi^+\pi^-\pi^+)= 1.70 \pm 0.10^{+0.11}_{-0.10}, where the first uncertainty is statistical and the second is related to systematic effects. Using established branching fractions for the B0→D∗−π+π−π+B^0 \to D^{*-}\pi^+\pi^-\pi^+ and B0→D∗−Ό+ΜΌB^0 \to D^{*-} \mu^+\nu_\mu modes, the lepton universality test, R(D∗−)≡B(B0→D∗−τ+Μτ)/B(B0→D∗−Ό+ΜΌ)\mathcal{R}(D^{*-}) \equiv \mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})/\mathcal{B}(B^0 \to D^{*-} \mu^+\nu_\mu) is calculated, R(D∗−)=0.247±0.015±0.015±0.012 , \mathcal{R}(D^{*-}) = 0.247 \pm 0.015 \pm 0.015 \pm 0.012\, , where the third uncertainty is due to the uncertainties on the external branching fractions. This result is consistent with the Standard Model prediction and with previous measurements.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-052.html (LHCb public pages

    Measurement of lepton universality parameters in B+→K+ℓ+ℓ−B^+\to K^+\ell^+\ell^- and B0→K∗0ℓ+ℓ−B^0\to K^{*0}\ell^+\ell^- decays

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    A simultaneous analysis of the B+→K+ℓ+ℓ−B^+\to K^+\ell^+\ell^- and B0→K∗0ℓ+ℓ−B^0\to K^{*0}\ell^+\ell^- decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q2q^2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 99 fb−1\text{fb}^{-1}. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2q^2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-045.html (LHCb public pages
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