31 research outputs found
Practical recommendations for safe reduction of body weight in combat sports: scoping review
The presence of weight categories in martial arts requires an athlete to constantly maintain and control body weight and, in some cases, to reduce it. For this reason, it is common among martial artists to use forced methods of body weight reduction, which are often unphysiological and may have a negative impact on performance, as well as pose a danger to health. In this connection, it is of practical interest to search, analyse and introduce into practice physiological and safe methods of body weight reduction by athletes-athletes before participation in competitions. The aim of the study is to evaluate the safety and effectiveness of various methods of weight loss in athletes preparing to participate in competitions.Materials and methods: the review was conducted according to the methodology of Scoping review. Articles were selected in the domestic data-bases eLibrary and Russian State Library, using the following keywords: «методы снижения массы тела ИЛИ снижение массы тела ИЛИ весогонка» И «единоборства ИЛИ боевые виды спорта», as well as in the foreign databases ScienceDirect and PubMed, using the following keywords: «making weight OR weight loss» AND «combat sports», placed in a search depth of 15 years.Results: we found 121 studies, 3 duplicates were excluded after initial screening, 118 studies were screened for inclusion criteria, and a total of 16 studies were included in the review.Conclusion: a reduction of 5 to 10 % of body weight less than 7 days before the official weigh-in may adversely affect performance parameters and the state of the body’s functional systems. A reduction of up to 5 % of body weight 7 or more days before the official weigh-in is the safest
Efficiency of isotonic drinks for rehydration of athletes of children and youth age
TThe most important factor limiting sports performance is insufficient fluid intake by athletes and dehydration of the body, while a significant decrease in performance and sports endurance begins with a dehydration level of 2 % and above.Objective: to study the effectiveness and safety of rehydration of the body of athletesskiers of children and youth using isotonic drinks «Izonok» and «Izonok+».Materials and methods: the main group (n = 12, 16.2 ± 1.4 years) took isotonic drinks for 30 days to compensate for fluid losses, the comparison group (n = 8, 15.7 ± 1.1 years) — drinking water. Bioimpedance body composition analysis was carried out on a KM-AR-01-”Diamant” device (RF, St.Petersburg), and central hemodynamic analysis was carried out on a «SIMONA 111» (LLC “Okulyus 2000”, RF). The content of secretory immunoglobulin A (sIgA) and lysozyme in saliva samples of athletes was carried out by the enzyme immunoassay on an ANTHOS 2010 analyzer (Austria). Statistical data processing was carried out using the Statistica 6.0 software package from Stat Soft @ Ink USA.Results: The intake of an isotonic drink is accompanied by the stimulation of the production of secretory immunoglobulin (sIgA) and lysozyme compared to the consumption of drinking water. The total volume of fluid and the volume of extracellular fluid tended to increase; the volume of intracellular fluid remained practically unchanged; the amount of total water when taking isotonic increased.Conclusion: The investigated isotonic drinks “Izonok” and “Izonok+” are effective sports drinks for maintaining optimal water-salt balance and local immunit
Luminosity-dependent changes of the cyclotron line energy and spectral hardness in Cepheus X-4
Context. X-ray spectra of accreting pulsars are generally observed to vary with their X-ray luminosity. In particular, the hardness of the X-ray continuum is found to depend on luminosity. In a few sources, the correlation between the energy of the cyclotron resonance scattering feature (CRSF) and the luminosity is clear. Different types (signs) of the correlation are believed to reflect different accretion modes.
Aims. We analyse two NuSTAR observations of the transient accreting pulsar Cep X-4 during its 2014 outburst. Our analysis is focused on a detailed investigation of the dependence of the CRSF energy and of the spectral hardness on X-ray luminosity, especially on short timescales.
Methods. To investigate the spectral changes as a function of luminosity within each of the two observations, we used the intrinsic variability of the source on the timescale of individual pulse cycles (tens of seconds), the so-called pulse-to-pulse variability.
Results. We find that the NuSTAR spectrum of Cep X-4 contains two CRSFs: the fundamental line at ~30 keV and its harmonic at ~55 keV. We find for the first time that the energy of the fundamental CRSF increases and the continuum becomes harder with increasing X-ray luminosity not only between the two observations, that is, on the long timescale, but also within an individual observation, on the timescale of a few tens of seconds. We investigate these dependencies in detail including their non-linearity. We discuss a possible physical interpretation of the observed behaviour in the frame of a simple one-dimensional model of the polar emitting region with a collisionless shock formed in the infalling plasma near the neutron star surface. With this model, we are able to reproduce the observed variations of the continuum hardness ratio and of the CRSF energy with luminosity
Plant and animal protein for muscle mass and strength gains: a systematic review
Background: Controversial approaches to studying the effect of proteins of various origins on the functional parameters of human skeletal muscles have led to the erroneous opinion that plant-based protein is a lesser stimulator of muscle mass growth and muscle strength than animal protein. Therefore, the purpose of this systematic review was to actually evaluate the effects of plant and animal protein intake on muscle mass and strength through studies comparing protein supplements.Methods: Literature search was carried out in the databases PubMed, Research Gate and the database of the Russian State Library. Studies were considered both in English and in Russian, over the past 20 years, filtered by date: from July 2002 to July 2022. Inclusion Criteria: Participants are healthy men and women over 18 years of age; taking protein supplements from plant products (soy, wheat, pea, rice, etc.); comparison with a group taking protein supplements from animal products (whey, beef, egg, etc.); studies assessed lean and/or muscle mass and assessed participants' muscle strength before and after supplementation; randomized controlled trial.Results: A total of 970 studies were found. After initial screening for title and abstract, 938 studies were excluded. Of the 32 publications selected, 5 duplicates were excluded, and after a secondary selection, 18 studies that did not meet the PICOS criteria were excluded. As a result of the search and selection, the review included 9 publications.Conclusions: Athletes and active individuals who prefer to consume plant-based protein products may not be inferior in terms of muscle strength and muscle mass to those athletes who prefer animal-based protein products. To further explore this topic, more randomized controlled trials should be conducted, taking into account the requirements for standardization and with a large number of participants.Registration: PROSPERO 2022 CRD4202234524
The Origins and Spread of Domestic Horses from the Western Eurasian Steppes
Domestication of horses fundamentally transformed long-range mobility and warfare1. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling2–4 at Botai, Central Asia around 3500 bc3. Other longstanding candidate regions for horse domestication, such as Iberia5 and Anatolia6, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association7 between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc8,9 driving the spread of Indo-European languages10. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture11,12. © 2021, The Author(s).We thank all members of the AGES group at CAGT. We are grateful for the Museum of the Institute of Plant and Animal Ecology (UB RAS, Ekaterinburg) for providing specimens. The work by G. Boeskorov is done on state assignment of DPMGI SB RAS. This project was supported by the University Paul Sabatier IDEX Chaire d’Excellence (OURASI); Villum Funden miGENEPI research programme; the CNRS ‘Programme de Recherche Conjoint’ (PRC); the CNRS International Research Project (IRP AMADEUS); the France Génomique Appel à Grand Projet (ANR-10-INBS-09-08, BUCEPHALE project); IB10131 and IB18060, both funded by Junta de Extremadura (Spain) and European Regional Development Fund; Czech Academy of Sciences (RVO:67985912); the Zoological Institute ZIN RAS (АААА-А19-119032590102-7); and King Saud University Researchers Supporting Project (NSRSP–2020/2). The research was carried out with the financial support of the Russian Foundation for Basic Research (19-59-15001 and 20-04-00213), the Russian Science Foundation (16-18-10265, 20-78-10151, and 21-18-00457), the Government of the Russian Federation (FENU-2020-0021), the Estonian Research Council (PRG29), the Estonian Ministry of Education and Research (PRG1209), the Hungarian Scientific Research Fund (Project NF 104792), the Hungarian Academy of Sciences (Momentum Mobility Research Project of the Institute of Archaeology, Research Centre for the Humanities); and the Polish National Science Centre (2013/11/B/HS3/03822). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie (grant agreement 797449). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreements 681605, 716732 and 834616)
The origins and spread of domestic horses from the Western Eurasian steppes
Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region.Domestication of horses fundamentally transformed long-range mobility and warfare(1). However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling(2-4) at Botai, Central Asia around 3500 bc(3). Other longstanding candidate regions for horse domestication, such as Iberia(5) and Anatolia(6), have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association(7) between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc(8,9) driving the spread of Indo-European languages(10). This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture(11,12).Descriptive and Comparative Linguistic
The origins and spread of domestic horses from the Western Eurasian steppes
Domestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 bc. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture
Ancient DNA reveals prehistoric gene-flow from Siberia in the complex human population history of north east Europe
North East Europe harbors a high diversity of cultures and languages, suggesting a complex genetic history. Archaeological, anthropological, and genetic research has revealed a series of influences from Western and Eastern Eurasia in the past. While genetic data from modern-day populations is commonly used to make inferences about their origins and past migrations, ancient DNA provides a powerful test of such hypotheses by giving a snapshot of the past genetic diversity. In order to better understand the dynamics that have shaped the gene pool of North East Europeans, we generated and analyzed 34 mitochondrial genotypes from the skeletal remains of three archaeological sites in northwest Russia. These sites were dated to the Mesolithic and the Early Metal Age (7,500 and 3,500 uncalibrated years Before Present). We applied a suite of population genetic analyses (principal component analysis, genetic distance mapping, haplotype sharing analyses) and compared past demographic models through coalescent simulations using Bayesian Serial SimCoal and Approximate Bayesian Computation. Comparisons of genetic data from ancient and modern-day populations revealed significant changes in the mitochondrial makeup of North East Europeans through time. Mesolithic foragers showed high frequencies and diversity of haplogroups U (U2e, U4, U5a), a pattern observed previously in European hunter-gatherers from Iberia to Scandinavia. In contrast, the presence of mitochondrial DNA haplogroups C, D, and Z in Early Metal Age individuals suggested discontinuity with Mesolithic hunter-gatherers and genetic influx from central/eastern Siberia. We identified remarkable genetic dissimilarities between prehistoric and modern-day North East Europeans/Saami, which suggests an important role of post-Mesolithic migrations from Western Europe and subsequent population replacement/extinctions. This work demonstrates how ancient DNA can improve our understanding of human population movements across Eurasia. It contributes to the description of the spatio-temporal distribution of mitochondrial diversity and will be of significance for future reconstructions of the history of Europeans.Clio Der Sarkissian, Oleg Balanovsky, Guido Brandt, Valery Khartanovich, Alexandra Buzhilova, Sergey Koshel, Valery Zaporozhchenko, Detlef Gronenborn, Vyacheslav Moiseyev, Eugen Kolpakov, Vladimir Shumkin, Kurt W. Alt, Elena Balanovska, Alan Cooper, Wolfgang Haak, the Genographic Consortiu
Changes in the cyclotron line energy on short and long timescales in V 0332+53
We present the results of the pulse-amplitude-resolved spectroscopy of the accreting pulsar V 0332+53 using the NuSTAR observations of the source in 2015 and 2016. We investigate the dependence of the energy of the cyclotron resonant scattering feature (CRSF) as a function of X-ray luminosity on timescales comparable with the spin period of the pulsar within individual observations, and the behavior on longer timescales within and between the two observed outbursts. We confirm that in both cases the CRSF energy is negatively correlated with flux at luminosities higher than the critical luminosity and is positively correlated at lower luminosities. We also confirm the recently reported gradual decrease in the line energy during the giant outburst in 2015. Using the NuSTAR data, we find that this decrease was consistent with a linear decay throughout most of the outburst, and flattened or even reversed at the end of the 2015 outburst, approximately simultaneously with the transition to the subcritical regime. We also confirm that by the following outburst in 2016 the line energy rebounded to previous values. The observed behavior of the CRSF energy with time is discussed in terms of changes in the geometry of the CRSF forming region caused by changes in the effective magnetospheric radius