338 research outputs found

    Tapering practices of New Zealand's elite raw powerlifters

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    Pritchard, HJ, Tod, DA, Barnes, MJ, Keogh, JW, and McGuigan, MR. Tapering practices of New Zealand's elite raw powerlifters. J Strength Cond Res 30(7): 1796-1804, 2016-The major aim of this study was to determine tapering strategies of elite powerlifters. Eleven New Zealand powerlifters (28.4 ± 7.0 years, best Wilks score of 431.9 ± 43.9 points) classified as elite were interviewed, using semistructured interviews, about their tapering strategies. Interviews were transcribed verbatim and content analyzed. Total training volume peaked 5.2 ± 1.7 weeks from competition while average training intensity (of 1 repetition maximum) peaked 1.9 ± 0.8 weeks from competition. During tapering, volume was reduced by 58.9 ± 8.4% while intensity was maintained (or slightly reduced) and the final weight training session was performed 3.7 ± 1.6 days out from competition. Participants generally stated that tapering was performed to achieve full recovery; that accessory work was removed around 2 weeks out from competition; and deadlifting takes longer to recover from than other lifts. Typically participants stated that trial and error, and changes based on "feel" were the sources of tapering strategies; equipment used and movements performed during tapering are the same as in competition; nutrition was manipulated during the taper (for weight cutting or performance aims); and poor tapering occurred when too long (1 week or more) was taken off training. These results suggest that athletes may benefit from continuing to strength train before important events with reduced volume and maintained intensity. Only exercises that directly assist sports performance should remain in the strength program during tapering, to assist with reductions in fatigue while maintaining/improving strength expression and performance

    Impact of prior accumulated work and intensity on power output in elite/international level road cyclists—a pilot study

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    Background. This study aimed to investigate the impact of the intensity of prior accumulated work on the decline in power output in elite/international level road cyclists, comparing the effects of prior continuous moderate intensity versus intermittent high intensity cycling.Methods. Nine elite/international level road cyclists (age 26.2 +/- 4.0 years; body mass: 66.6 +/- 5.5 kg; height: 176 +/- 0.4 cm) conducted a 12-min field test (12 min(fresh)) during two consecutive training camps. Participants then performed both a 150-min moderate intensity continuous (MIC) work bout or a 150-min high intensity intermittent (HII) race simulation in randomized order, cross-over design. After each condition a 12-min field test (12 min(fatigue)) was completed.Results. Absolute and relative 12min(fresh) power output were not significantly different between training camps (p>0.05). The 12 min(fatigue) power after HII was significantly lower than 12min(fatigue) after MIC (Delta=14W; p=0.014). Participants recorded more percentage time (%Time) in heart rate (HR) zone 3 (Delta=9.2%; p=0.003) and power output band between 5.0-7.9W.kg(-1) (Delta=8.9%; p=0.002) as well as higher total work (Delta=237 kJ; p <= 0.001) during HII.Conclusion. These findings reveal that the decline in power output is higher after HII compared to MIC cycling work bouts. This suggests that the quantification of total work and intensity should be used in conjunction to predict a distinctive decline in power output. Future research is required to better understand the mechanisms of endurance "durability" in elite/international level road cyclists

    The interaction of aluminum with catecholamine-based neurotransmitters: Can the formation of these species be considered a potential risk factor for neurodegenerative diseases?

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    The potential neurotoxic role of Al(iii) and its proposed link with the insurgence of Alzheimer's Disease (AD) have attracted increasing interest towards the determination of the nature of bioligands that are propitious to interact with aluminum. Among them, catecholamine-based neurotransmitters have been proposed to be sensitive to the presence of this non-essential metal ion in the brain. In the present work, we characterize several aluminum-catecholamine complexes in various stoichiometries, determining their structure and thermodynamics of formation. For this purpose, we apply a recently validated computational protocol with results that show a remarkably good agreement with the available experimental data. In particular, we employ Density Functional Theory (DFT) in conjunction with continuum solvation models to calculate complexation energies of aluminum for a set of four important catecholamines: l-DOPA, dopamine, noradrenaline and adrenaline. In addition, by means of the Quantum Theory of Atoms in Molecules (QTAIM) and Energy Decomposition Analysis (EDA) we assessed the nature of the Al-ligand interactions, finding mainly ionic bonds with an important degree of covalent character. Our results point at the possibility of the formation of aluminum-catecholamine complexes with favorable formation energies, even when proton/aluminum competition is taken into account. Indeed, we found that these catecholamines are better aluminum binders than catechol at physiological pH, because of the electron withdrawing effect of the positively-charged amine that decreases their deprotonation penalty with respect to catechol. However, overall, our results show that, in an open biological environment, the formation of Al-catecholamine complexes is not thermodynamically competitive when compared with the formation of other aluminum species in solution such as Al-hydroxide, or when considering other endogenous/exogenous Al(iii) ligands such as citrate, deferiprone and EDTA. In summary, we rule out the possibility, suggested by some authors, that the formation of Al-catecholamine complexes in solution might be behind some of the toxic roles attributed to aluminum in the brain. An up-to-date view of the catecholamine biosynthesis pathway with sites of aluminum interference (according to the current literature) is presented. Alternative mechanisms that might explain the deleterious effects of this metal on the catecholamine route are thoroughly discussed, and new hypotheses that should be investigated in future are proposed

    Effects of Bed Rest on Physical Performance in Athletes: A Systematic and Narrative Review.

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    BACKGROUND: Athletes can face scenarios in which they are confined to bed rest (e.g., due to injury or illness). Existing research in otherwise healthy individuals indicates that those entering bed rest with the greatest physical performance level might experience the greatest performance decrements, which indirectly suggests that athletes might be more susceptible to the detrimental consequences of bed rest than general populations. Therefore, a comprehensive understanding of the effects of bed rest might help guide the medical care of athletes during and following bed rest. OBJECTIVE: This systematic and narrative review aimed to (1) establish the evidence for the effects of bed rest on physical performance in athletes; (2) discuss potential countermeasures to offset these negative consequences; and (3) identify the time-course of recovery following bed rest to guide return-to-sport rehabilitation. METHODS: This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Four databases were searched (SPORTDiscus, Web of Science, Scopus, and MEDLINE/PubMed) in October of 2022, and studies were included if they were peer-reviewed investigations, written in English, and investigated the effects of horizontal bed rest on changes in physical capacities and qualities in athletes (defined as Tier 3-5 participants). The reporting quality of the research was assessed using a modified version of the Downs & Black checklist. Furthermore, findings from studies that involved participants in Tiers 1-2 were presented and synthesized using a narrative approach. RESULTS: Our systematic review of the literature using a rigorous criterion of 'athletes' revealed zero scientific publications. Nevertheless, as a by-product of our search, seven studies were identified that involved apparently healthy individuals who performed specific exercise training prior to bed rest. CONCLUSIONS: Based on the limited evidence from studies involving non-athletes who were otherwise healthy prior to bed rest, we generally conclude that (1) bed rest rapidly (within 3 days) decreases upright endurance exercise performance, likely due to a rapid loss in plasma volume; whereas strength is reduced within 5 days, likely due to neural factors as well as muscle atrophy; (2) fluid/salt supplementation may be an effective countermeasure to protect against decrements in endurance performance during bed rest; while a broader array of potentially effective countermeasures exists, the efficacy of these countermeasures for previously exercise-trained individuals requires further study; and (3) athletes likely require at least 2-4 weeks of progressive rehabilitation following bed rest of ≤ 28 days, although the timeline of recovery might need to be extended depending on the underlying reason for bed rest (e.g., injury or illness). Despite these general conclusions from studies involving non-athletes, our primary conclusion is that substantial effort and research is still required to quantify the effects of bed rest on physical performance, identify effective countermeasures, and provide return-to-sport timelines in bona fide athletes. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: Registration ID: osf.io/d3aew; Date: October 24, 2022

    SEOM clinical guideline for the management of cutaneous melanoma (2020)

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    Tractament adjuvant; Melanoma; EscenificacióAdjuvant treatment; Melanoma; StagingTratamiento adyuvante; Melanoma; EscenificaciónMelanoma affects about 6000 patients a year in Spain. A group of medical oncologists from Spanish Society of Medical Oncology (SEOM) and Spanish Multidisciplinary Melanoma Group (GEM) has designed these guidelines to homogenize the management of these patients. The diagnosis must be histological and determination of BRAF status has to be performed in patients with stage ≥ III. Stage I–III resectable melanomas will be treated surgically. In patients with stage III melanoma, adjuvant treatment with immunotherapy or targeted therapy is also recommended. Patients with unresectable or metastatic melanoma will receive treatment with immunotherapy or targeted therapy, the optimal sequence of these treatments remains unclear. Brain metastases require a separate consideration, since, in addition to systemic treatment, they may require local treatment. Patients must be followed up closely to receive or change treatment as soon as their previous clinical condition changes, since multiple therapeutic options are available

    Improved microfluidic platform for simultaneous multiple drug screening towards personalized treatment

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    Development of new targeted therapies is a challenge in the battle against cancer. Although a variety of treatments is currently available, there is no technique for rapidly evaluating the response of cancer patients to the drug. In this work, a microfluidic platform for the real-time simultaneous analysis of the success rate of different nanoparticle based chemotherapeutic drugs is presented. Based on a previous planar chamber and a reported sensitivity enhancing strategy, linear and cross shape microstructures were integrated into the chamber dome of the microfluidic polydimethylsiloxane and glass platform in order to provide a higher fluid mixing and treatment-cell interaction. Several methotrexate (MTX) based treatments (free MTX, MTX loaded Lecithin-PVA nanoparticles, MTX loaded Lecithin-Tween 80 nanoparticles) as well as their respective controls (cell media and both blank nanoparticles) were recirculated through the microchamber over an osteosarcoma cell monolayer. These nanovehicles reduced cell population to less than 20% (LEC-PVA nanoparticles) and 2.3% (LEC-Tween nanoparticles), demonstrating that nanoparticles are a promising target therapy for cancer treatment. Moreover, microstructured platforms demonstrated a higher efficacy in the drug-screening process: due to the liquid folding a higher amount of nanoparticles was internalized by the cells and, therefore, results were observed faster. In fact, the time required to reduce cell viability to the half was nearly a 75% faster. Furthermore, this microfluidic platform offers the capability to test up to five different drugs simultaneously, making it a powerful tool to evaluate the effect of multiple drugs and determine the most effective and personalized treatment

    Screening young athletes for prevention of sudden cardiac death: Practical recommendations for sports physicians

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    Regular intensive exercise in athletes increases the relative risk of sudden cardiac death (SCD) compared with the relatively sedentary population. Most cases of SCD are due to silent cardiovascular diseases, and preparticipation screening of athletes at risk of SCD is thus of major importance. However, medical guidelines and recommendations differ widely between countries. In Italy, the National Health System recommends preparticipation screening for all competitive athletes including personal and family history, a physical examination, and a resting 12-lead electrocardiogram (ECG). In the United States, the American College of Cardiology and the American Heart Association recommend a preparticipation screening program limited to the use of specific questionnaires and a clinical examination. The value of a 12-lead ECG is debated based on issues surrounding cost-efficiency and feasibility. The aim of this review was to focus on (i) the incidence rate of cardiac diseases in relation to SCD; (ii) the value of conducting a questionnaire and a physical examination; (iii) the value of a 12-lead resting ECG; (iv) the importance of other cardiac evaluations in the prevention of SCD; and (v) the best practice for pre-participation screening

    Aluminum's preferential binding site in proteins: sidechain of amino acids versus backbone interactions

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    The interaction of aluminum ion Al(III) with polypeptides is a subject of paramount importance, since it is a central feature to understand its deleterious effects in biological systems. Various drastic effects have been attributed to aluminum in its interaction with polypeptides and proteins. These interactions are thought to be established mainly through the binding of aluminum to phosphorylated and non-phosphorylated amino acid sidechains. However, a new structural paradigm has recently been proposed, in which aluminum interacts directly with the backbone of the proteins, provoking drastic changes in their secondary structure and leading ultimately to their denaturation. In the present paper, we use computational methods to discuss the possibility of aluminum to interact with the backbone of peptides and compare it with the known ability of aluminum to interact with amino acid sidechains. To do so, we compare the thermodynamics of formation of prototype aluminum-backbone structures with prototype aluminum-sidechain structures, and compare these results with previous data generated in our group in which aluminum interacts with various types of polypeptides and known aluminum biochelators. Our results clearly points to a preference of aluminum towards amino acid sidechains, rather than towards the peptide backbone. Thus, structures in which aluminum is interacting with the carbonyl group are only slightly exothermic, and they become even less favorable if the interaction implies additionally the peptide nitrogen. However, structures in which aluminum is interacting with negatively-charged sidechains like aspartic acid, or phosphorylated serines are highly favored thermodynamically.Technical and human support was provided by SGI/IZO (SGIker) of UPV/EHU and European funding (ERDF and ESF). Financial support comes from UPV/EHU (PES14/35), Eusko Jaurlaritza (IT588-13) and the Spanish Ministerio de Ciencia e Innovación (MINECO/FEDER) (CTQ2015-67608-P). GdT thanks the European Union for a Ph.D. grant inside the ITN-TCCM-642294 program
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