906 research outputs found
Exercise-Based Strategies to Prevent Muscle Injury in Male Elite Footballers: An Expert-Led Delphi Survey of 21 Practitioners Belonging to 18 Teams from the Big-5 European Leagues.
PurposeTo define based on expert opinion and practical experience using a systematic and scientific approach, (1) the perceived most effective exercise-based strategies to prevent muscle injury in elite footballers; and, (2) when and how these exercise programs are prescribed based on the number of days between games i.e. implementation strategy.MethodsA Delphi survey obtained opinions and assessed for agreement. Delphi respondents consisted of 21 experienced sports practitioners (12âÂąâ5.3 years in elite football and with an academic background) belonging to 18 teams from the Big-5 European football leagues; England, France, Germany, Italy, Spain. Three teams were represented collaboratively by two experts. The Delphi process involves sequential rounds each evolving based on the responses from the previous. The number of rounds is not pre-defined and continues until an agreement is either achieved or it is clear that no agreement will be reached. Frequency of responses was recorded where the agreement was sought (i.e. in closed questions) and an agreement was achieved ifââĽâ13/18 (70%) respondents agreed. For open-ended questions, a qualitative content analysis was performed to identify recurring themes and when themes were specified byââĽâ13 (70%), these were also considered as reaching an agreement. Practitioners had the opportunity to raise concerns if they disagreed with the 'agreement from recurrent themes'.ResultsThere were four Delphi rounds (100% response for each round). Sprinting and High-Speed Running (HSR) focused exercises were agreed as most effective (perceived) to prevent muscle injuries. Eccentric exercise was perceived as the next most effective. It was agreed that sprinting and HSR be integrated into coaches training, and target 100% of players worst-case match scenario (e.g. volume, intensity) based on individual maximum speeds. Eccentric exercise was recommended to be implemented according to the context of the main football session and planned/actual sprinting and HSR content. It was agreed that eccentrics can be performed before or after training, context dependent. The day to perform specific sprinting and HSR or eccentric exercises depended on the proximity of previous and upcoming matches. Other exercises reaching agreement as 'somewhat effective' included concentric and isometric, horizontal and vertical plyometrics, coordination, core and dynamic flexibility in addition to core stability. No agreement was reached for multi-joint, resisted sprinting, kicking or agility exercises nor simultaneous single-leg strength and stability. Finally, no agreement was reached regarding programming variables e.g. sets, repetitions as deemed too contextual.ConclusionRegarding exercise-based strategies, particular importance agreed by the Delphi expert group was to focus on sprinting, HSR and eccentric exercises, integrated with a variety of other exercise modes which also carry some level of effectiveness in a multidimensional programme. Context was agreed to be key and decision-making about when to undertake/ how to prescribe exercise strategies to be made according to the content of normal football training and the proximity of matches
The wheat Ď-gliadin genes: structure and EST analysis
A survey and analysis is made of all available Ď-gliadin DNA sequences including Ď-gliadin genes within a large genomic clone, previously reported gene sequences, and ESTs identified from the large wheat EST collection. A contiguous portion of the Gli-B3 locus is shown to contain two apparently active Ď-gliadin genes, two pseudogenes, and four fragments of the 3Ⲡportion of Ď-gliadin sequences. Comparison of Ď-gliadin sequences allows a phylogenetic picture of their relationships and genomes of origin. Results show three groupings of Ď-gliadin active gene sequences assigned to each of the three hexaploid wheat genomes, and a fourth group thus far consisting of pseudogenes assigned to the A-genome. Analysis of Ď-gliadin ESTs allows reconstruction of two full-length model sequences encoding the AREL- and ARQL-type proteins from the Gli-A3 and Gli-D3 loci, respectively. There is no DNA evidence of multiple active genes from these two loci. In contrast, ESTs allow identification of at least three to four distinct active genes at the Gli-B3 locus of some cultivars. Additional results include more information on the position of cysteines in some Ď-gliadin genes and discussion of problems in studying the Ď-gliadin gene family
Movement characteristics, physiological and perceptual responses of elite standard youth football players to different high intensity running drills
This is an Accepted Manuscript of an article published by Taylor & Francis in Science and Medicine in Football on 06/04/2018, available online: https://doi.org/10.1080/24733938.2018.1461235Purpose: To examine responses to high intensity running drills in youth football players. Methods: Seventeen players completed the YoYo Intermittent Recovery test level one (YYIR1) and a 15 m maximal sprint to quantify target running speeds. Players performed three conditions on separate occasions comprising: 12 x 15 s high intensity runs at 100% of the final YYIRT1 speed, 12 x ~4 s repeated sprints with ~26 s recovery, and combination running using both modalities. Heart rate was monitored continuously with PlayerLoadTM and movement characteristics using microtechnology. Ratings of perceived exertion and blood lactate responses were measured 2 min after the final repetition. The ratio of Flight:contraction time was calculated from a countermovement jump before and at 2 min and 14 hours after each condition. Data analysis used magnitude based inferences and effect sizes statistics. Results: Peak speed (1.1%; ES 0.23 Âą 0.44) and mean speed over the initial 4s (6.3%; ES 0.45 Âą 0.46) were possibly faster during combination compared to high intensity running with unclear differences when compared to repeated sprinting. This was despite most likely (21.6%; ES 7.65 Âą 1.02) differences in prescribed speeds between conditions. There were likely reductions in F:C at 14 hours ratio after high intensity (-5.6%; ES â0.44 Âą 0.32) and combination running (-6.8%; ES -0.53 Âą 0.47). Changes in the repeated sprinting condition were unclear. Conclusions: Actual movement characteristics of high intensity running drills may not reflect those used to prescribe them whilst reductions in F:C ratio are still evident 14 hours after their completion
Changes of direction during high-intensity intermittent runs: neuromuscular and metabolic responses
Characterization of globulin storage proteins of a low prolamin cereal species in relation to celiac disease
Brachypodium distachyon, a small annual grass with seed storage globulins as primary protein reserves was used in our study to analyse the toxic nature of non-prolamin seed storage proteins related to celiac disease. The main storage proteins of B. distachyon are the 7S globulin type proteins and the 11S, 12S seed storage globulins similar to oat and rice. Immunoblot analyses using serum samples from celiac disease patients were carried out followed by the identification of immune-responsive proteins using mass spectrometry. Serum samples from celiac patients on a gluten-free diet, from patients with Crohn's disease and healthy subjects, were used as controls. The identified proteins with intense serum-IgA reactivity belong to the 7S and 11-12S seed globulin family. Structure prediction and epitope predictions analyses confirmed the presence of celiac disease-related linear B cell epitope homologs and the presence of peptide regions with strong HLA-DQ8 and DQ2 binding capabilities. These results highlight that both MHC-II presentation and B cell response may be developed not only to prolamins but also to seed storage globulins. This is the first study of the non-prolamin type seed storage proteins of Brachypodium from the aspect of the celiac disease
Co-activation: its association with weakness and specific neurological pathology
BACKGROUND: Net agonist muscle strength is in part determined by the degree of antagonist co-activation. The level of co-activation might vary in different neurological disorders causing weakness or might vary with agonist strength. AIM: This study investigated whether antagonist co-activation changed a) with the degree of muscle weakness and b) with the nature of the neurological lesion causing weakness. METHODS: Measures of isometric quadriceps and hamstrings strength were obtained. Antagonist (hamstring) co-activation during knee extension was calculated as a ratio of hamstrings over quadriceps activity both during an isometric and during a functional sit to stand (STS) task (using kinematics) in groups of patients with extrapyramidal (n = 15), upper motor neuron (UMN) (n = 12), lower motor neuron (LMN) with (n = 18) or without (n = 12) sensory loss, primary muscle or neuromuscular junction disorder (n = 17) and in healthy matched controls (n = 32). Independent t-tests or Mann Witney U tests were used to compare between the groups. Correlations between variables were also investigated. RESULTS: In healthy subjects mean (SD) co-activation of hamstrings during isometric knee extension was 11.8 (6.2)% and during STS was 20.5 (12.9)%. In patients, co-activation ranged from 7 to 17% during isometric knee extension and 15 to 25% during STS. Only the extrapyramidal group had lower co-activation levels than healthy matched controls (p < 0.05). Agonist isometric muscle strength and co-activation correlated only in muscle disease (r = -0.6, p < 0.05) and during STS in UMN disorders (r = -0.7, p < 0.5). CONCLUSION: It is concluded that antagonist co-activation does not systematically vary with the site of neurological pathology when compared to healthy matched controls or, in most patient groups, with strength. The lower co-activation levels found in the extrapyramidal group require confirmation and further investigation. Co-activation may be relevant to individuals with muscle weakness. Within patient serial studies in the presence of changing muscle strength may help to understand these relationships more clearly
Uncovering the effect of low-frequency static magnetic field on tendon-derived cells: from mechanosensing to tenogenesis
Magnetotherapy has been receiving increased attention as an attractive strategy for modulating cell physiology directly at the site of injury, thereby providing the medical community with a safe and non- invasive therapy. Yet, how magnetic eld in uences tendon cells both at the cellular and molecular levels remains unclear. Thus, the in uence of a low-frequency static magnetic eld (2 Hz, 350 mT) on human tendon-derived cells was studied using di erent exposure times (4 and 8 h; short-term studies) and di erent regimens of exposure to an 8h-period of magnetic stimulation (continuous, every 24 h or every 48 h; long-term studies). Herein, 8 h stimulation in short-term studies signi cantly upregulated the expression of tendon-associated genes SCX, COL1A1, TNC and DCN (p < 0.05) and altered intracellular Ca2+ levels (p < 0.05). Additionally, every 24 h regimen of stimulation signi cantly upregulated COL1A1, COL3A1 and TNC at day 14 in comparison to control (p < 0.05), whereas continuous exposure di erentially regulated the release of the immunomodulatory cytokines IL-1Ă² and IL-10 (p < 0.001) but only at day 7 in comparison to controls. Altogether, these results provide new insights on how low-frequency static magnetic eld ne-tune the behaviour of tendon cells according to the magnetic settings used, which we foresee to represent an interesting candidate to guide tendon regeneration.info:eu-repo/semantics/publishedVersio
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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