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ABSTRACT Anguilliform swimmers are long and narrow animals that propel themselves by undulating their bodies. Observations in nature and recent investigations suggest that anguilliform swimming is highly efficient. However, understanding the underlying reasons for the efficiency of this type of locomotion requires interdisciplinary studies spanning from biology to hydrodynamics. Regrettably, these different fields are rarely discussed together, which hinders our ability to understand the repeated evolution of this swimming mode in vertebrates. This review compiles the current knowledge of the anatomical features that drive anguilliform swimming, compares the resulting kinematics across a wide range of anguilliform swimmers, and describes the resulting hydrodynamic interactions using data from both in vivo experiments and computational studies. [ABSTRACT FROM AUTHOR]

During the Interwar period, female athletes from Denmark dominated international swimming competitions. It was the first time that the country demonstrated sporting success in a core Olympic discipline on the global sporting level. Most of the Danish swimmers had the same coach, the co-leader of the Institute of Danish Women's Gymnastics (DKI), Ingeborg Paul-Petersen. Based on archival sources and historical newspaper reports, this paper shows that Paul-Petersen's role as an educator in the DKI and her vast experience in swimming training provided her with the perfect skills and context to develop her athletes into elite swimmers. She profited from the unique environment at the DKI that led her to approach coaching as a combination of motherly care for her young athletes and a discipling. However, Paul-Petersen avoided publicity and therefore her extraordinary achievements remained largely unnoticed until date. [ABSTRACT FROM AUTHOR]

A bistable mechanism has two stable states with energy input required to move from one stable state to another. This energy barrier allows for energy storage and release which can be used to improve systems characteristics. Bistability has been used to increase the frequency range over which a kinetic energy harvester is effective, and it has been proposed that bistability can increase the efficiency of biomimetic swimming robots. However, experiments involving bistable swimming robots have typically used bistability as a means of overcoming limitations inherent to soft actuators, rather than to increase overall performance. This article implements bistability into a swimming robotic and compares performance with and without bistable action. The static thrust generation and power consumption for bistable and nonbistable configurations for five different tail morphologies are compared. Bistability is generally found to increase the system efficiency, particularly at lower frequencies where increases are observed up to 250%. The untethered swimming speed of the robot in open water is also found to increase by approximately 30%. The results show that bistability can offer direct performance benefits for biomimetic swimming, but that the bistable transmission must be well tuned to the dynamics of the rest of the system. [ABSTRACT FROM AUTHOR]

The present study discusses the numerical simulation results of swimming similar to manta rays. The complex three-dimensional kinematics of manta rays were implemented to unravel the intricacies of its propulsion mechanisms by using the discrete vortex method (DVM). The DVM replaces the requirement for a structured grid across the computational domain with a collection of vortex elements. This method simplifies grid generation, especially for intricate geometries, resulting in time and effort savings in meshing complex shapes. By modeling the pectoral fins with discrete panels and utilizing vortex rings to represent circulation and wake, the study accurately computes the pressure distribution, circulation distribution, lift coefficient, and thrust coefficient of the manta ray. This study focuses on the modulation of aerodynamic performance by altering the span length and the length change ratio during the downstroke and upstroke motion ( S V ). The manta ray's three-dimensional vortex configurations comprise a combination of vortex rings, vortex contrails, and horseshoe vortices. Analysis of the three-dimensional vortex structure indicates the presence of multiple vortex rings and horseshoe vortex rings at higher S V values, while adequate formation of horseshoe vortices is not observed at lower S V values. In terms of propulsive performance, both lift and thrust increase with S V , while the propulsive efficiency demonstrates its peak at S V = 1.75. The analysis reveals that at higher S V values, the net thrust generated primarily originates from the tip of the fins. Moreover, the study illustrates a significant enhancement in propulsive efficiency, particularly in association with optimal Strouhal numbers ranging between 0.3 and 0.4. The key findings of this study may be used in efficient design of agile autonomous underwater vehicles for marine exploration and surveillance applications. [ABSTRACT FROM AUTHOR]

The perception of fish locomotion is important for understanding their adaptive behaviors and ethological characteristics. However, the main strategy used for extracting fish attitudes involves the use of a vision-based monitoring system, which is limited in its range of observation and cannot perform tracking for long times. Here, we report the use of a wearable tagging electronic device, referred to as an underwater vest, to capture the surrounding flow field disturbances triggered by swimming or momentary postural changes. All of these goals were achieved by integrating a pair of pseudocapacitive pressure-sensing units and a flexible circuit board. Notably, additional conditions, such as variable hydraulic pressures and minimal changes in fish posture, require high stability and sensitivity of the sensing units. Thus, hybrid hydrogel electrodes were developed through cross-linking MXene with holey-reduced graphene oxide nanosheets and further modification with 1-ethyl-3-methylimidazolium dicyanamide ionic liquids, which increased the interfacial capacitance and long-term interfacial activity of the MXene. Consequently, the sensing unit exhibited ultrahigh sensitivity (Smax~136,207 kPa−1) in an aquatic environment for 60 days and superior high-pressure resolution (10 Pa) within a wide working range of 1 MPa. Ultimately, an underwater vest integrated with such sensing units clearly distinguished and recorded fish locomotion. We believe that the designed device may open avenues in flow field monitoring and ocean current detection and provide new insights into the development of sensitive underwater tagging. [ABSTRACT FROM AUTHOR]

This note reports on eight observations of inverted swimming behavior by species of ceratioid whipnose anglerfishes in the genus Gigantactis, from the Caribbean, tropical east Atlantic, tropical western Indian Ocean, the north‐east and north‐west Pacific and south‐west Pacific. It covers four putative species and strongly suggests that this is the normal behavior for the genus. A possible reason is briefly discussed. In addition, a new depth record of 5866 m for the ceratioid anglerfish is recorded. [ABSTRACT FROM AUTHOR]

The research aims to design a training program using a speed change strategy and identify: - Its effect on some physical variables for middle-distance swimmers. - Its impact on the digital level of middle-distance swimmers. The experimental method was used by applying pre- and post-measurements to two groups, one experimental and the other a control group of junior swimming players. The research population consisted of junior swimming players enrolled in the private academy, inside the Cleopatra Park swimming pool in Matrouh Governorate. The research sample was chosen intentionally from junior swimming players enrolled in the private academy from the stage Age: 14-16 years, The total population of the selected sample was 18 emerging players, including 8 individuals for the exploratory study and 10 individuals for the basic study, divided into two experimental and control groups who met the conditions for selecting the sample. The researcher concluded the following: - A strategy of changing speed works to improve the physical abilities of budding swimmers. - A speed change strategy that improves the digital level of middle-distance swimming among emerging swimmers. - Speed change strategy allows control of swimming rhythm and sense of time. -The strategy of changing speed is appropriate to the nature of competition in middle-distance swimming among juniors. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to identify Key Performance Indicators (KPIs) for men's swimming strokes using Principal Component Analysis (PCA) and Multiple Regression Analysis to enhance training strategies and performance optimization. The analyses included all men's individual 100 m races of the 2019 European Short-Course Swimming Championships. Results: Duration from 5 m prior to wall contact (In5) emerged as a consistent KPI for all strokes. Free Swimming Speed (FSS) was identified as a KPI for 'continuous' strokes (Breaststroke and Butterfly), while duration from wall contact to 10 m after (Out10) was a crucial KPI for strokes with touch turns (Breaststroke and Butterfly). The regression model accurately predicted swim times, demonstrating strong agreement with actual performance. Bland and Altman analyses revealed negligible mean biases: Backstroke (0% bias, LOAs − 2.3% to + 2.3%), Breaststroke (0% bias, LOAs − 0.9% to + 0.9%), Butterfly (0% bias, LOAs − 1.2% to + 1.2%), and Freestyle (0% bias, LOAs − 3.1% to + 3.1%). This study emphasizes the importance of swift turning and maintaining consistent speed, offering valuable insights for coaches and athletes to optimize training and set performance goals. The regression model and predictor tool provide a data-driven approach to enhance swim training and competition across different strokes. [ABSTRACT FROM AUTHOR]

Understanding the external load demands of basketball games is fundamental information for training planning and programming. However, there is a scarcity of information about external load during official games at high-level basketball. The purpose of this research was to investigate basketball game external load differences between two elite basketball teams involved in separate competitions. External load demands experienced by forty-six elite basketball players (from two teams) were analyzed using inertial devices during official basketball games. External load was expressed with calculated (PlayerLoad, PL, averaged and in different time epochs) and inertial movement analysis variables (acceleration, deceleration, change of direction and jump). The results showed that the Euroleague team had a higher peak PL in epochs of 30-s (p<.001) and 60-s (p=.02) with moderate and small effect sizes compared to the Eurocup team. The Eurocup team had a significantly higher number of low and moderate accelerations and changes of direction with effect sizes from 0.34 to 1.15. In conclusion, external load demands in basketball vary depending on the team and league therefore practitioners should consider the specific level and style of play when comprising a training plan. Furthermore, practitioners should rely on their own team's external load values for training load management, rather than attempting to adhere to standards established by external sources. [ABSTRACT FROM AUTHOR]

The article presents a framework for a Bioinformatics competition that focuses on 4 key aspects: structure, model, overview, and perspectives. Structure represents the organizational framework employed to coordinate the main tasks involved in the competition. Model showcases the competition design, which encompasses 3 phases. Overview presents our case study, the League of Brazilian Bioinformatics (LBB) 2nd Edition. Finally, the section on perspectives provides a brief discussion of the LBB 2nd Edition, along with insights and feedback from participants. LBB is a biannual team competition launched in 2019 to promote the ongoing training of human resources in Bioinformatics and Computational Biology in Brazil. LBB aims to stimulate ongoing training in Bioinformatics by encouraging participation in competitions, promoting the organization of future Bioinformatics competitions, and fostering the integration of the Bioinformatics and Computational Biology community in the country, as well as collaboration among participants. The LBB 2nd Edition was launched in 2021 and featured 251 competitors forming 91 teams. Knowledge competitions promote learning, collaboration, and innovation, which are crucial for advancing scientific knowledge and solving real-world problems. In summary, this article serves as a valuable resource for individuals and organizations interested in developing knowledge competitions, offering a model based on our experience with LBB to benefit all levels of Bioinformatics trainees. Author summary: There are various methods of learning, and one such approach involves a commonly used in the computing field, fostering competition, where communication, teamwork, group learning, and problem-solving play crucial roles. Similarly, in bioinformatics and computational biology, certain institutions or platforms promote learning through challenges. However, national-level competitions in these domains are relatively scarce. Here, we would like to present a framework for a Bioinformatics competition by showing structure, model, overview, and perspectives, using the League of Brazilian Bioinformatics (LBB) 2nd Edition as case study. LBB is the first bioinformatics competition in Latin America and aims to encompass the diverse multidisciplinary aspects of Bioinformatics and promote networking. In LBB, individuals not only have the opportunity to learn but also get to know one another. Further, to stimulate undergraduate training, we promoted teams with a mixture of different academic backgrounds. This approach promotes integration among participants and facilitates the exchange of information. To ensure that all participants have the opportunity to connect and form teams regardless of their background, we have created the MATCH, a script that allows individuals to be randomly paired with others, enabling them to get to know each other and create teams effectively. This approach fosters collaboration and creates a conducive environment for learning and problem-solving. [ABSTRACT FROM AUTHOR]

Hybrid figures serve as an important component of artistic swimming, however, no prior research has investigated objective indicators for predicting total scores in competition. This study aimed to identify significance of hybrid figure (HF) elements in predicting total scores in artistic swimming competitions and compare these variables between the Beijing team trials and international official competitions. Eight HF variables were measured in the videos from the international artistic swimming competitions, with calibration and measurement of the variables leg height index and leg angle deviation being performed by means of Kinovea. Multiple linear regression was conducted to predict the total scores based on these variables investigated for the international teams, which showed 5 significant predictors including movement frequency, leg height index, leg angle deviation, mean pattern duration, and rotation frequency. Wilcoxon signed-rank test was used to determine the differences in the variables between the Beijing team and the international teams (top 5), which showed significant difference on movement frequency, leg angle deviation, leg height index and total score. When designing hybrid figures choreography of team free routine in artistic swimming, coaches should prioritize appropriate movement frequency, pattern changes and rotations over excessively long durations. Overly complex HF choreography may lead to a decline on performance in artistic swimming competition. [ABSTRACT FROM AUTHOR]

Objectives. The relative contribution of each of the four strokes to performance, and whether these contributions differ substantially between short course and long course competitions is unclear. To clarify these issues the aim of this study was to assess the strokes that have more influence on the performance in the 200 and 400 m IM swimming performances of elite male and female swimmers, participating in major events: Olympic Games (OG) and World Championship (WC) in short-course and long-course from 2012 to 2021. Methods. Data from 1,095 swimmers (501 women and 594 men) who competed in 200 and 400-m IM were obtained with a minimum level of 800 FINA points. Linear regression modelling and classification trees were employed to quantify differences between strokes and short/long course swimming. Results. Regression analysis indicated that breaststroke (β =-0:191; p<0:000) and backstroke (β = -0:185; p < 0:000) had a bigger effect on IM performance, with butterfly (β =-0:101; p<0:000) having a lesser impact. The classification trees showed threshold performance standards in terms of 50-m times in form-stroke events must be fulfilled to attain medal-winning performances. Conclusions. These form-stroke standards represent important milestones for designing medal-oriented training strategies for both 200 IM and 400 m IM. Achieving a medallist position in 200 and 400 m IM requires obtaining specified lap times in butterfly, breaststroke and backstroke for males and females in long-course competitions, and breaststroke and backstroke for short-course competitions. The OG presents more exigent demands of lap times in butterfly, crawl and backstroke for IM swimmers. [ABSTRACT FROM AUTHOR]

The capacity of laboratory tests to predict competition performance has been broadly researched across several endurance sports. The aim of the present study was to analyse how pool swimming performance can predict the result of the swimming segment in triathlon competitions and compare predictability differences based on competition level and distance. Eighteen male triathletes participated in the study. Three were ranked world-class, ten elite/international level, and five highly trained/national level. A total of sixty-one graded multi-stage swimming tests were conducted. Blood lactate was measured to calculate the following hypothetical predictor variables: speed at lactate threshold 1 (LT1), speed at lactate threshold 2 (LT2), and speed in the last repetition of the test (SL200). The following data were collected for a total of 75 races: time in the swimming leg (TSL); position after the swimming leg (PSL); time difference with the first triathlete after the swimming leg (DFT); and final race position. The race levels were divided according to participant levels as follows: world series (WS) (n = 22); World Cup (WC) (n = 22); Continental Cup (CC) (n = 19); national championship (N) (n = 5); and local race (L) (n = 5). Based on distance, they were divided into Olympic distance (OD) (n = 37) and sprint distance (SD) (n = 38). A moderate to strong positive association was found between LT1, LT2, SL200 and PSL and TSl at all race levels except for the SD CC, SD WC, and OD CC races, where no or weak-to-moderate correlations were found. The present study demonstrated that performance measured in a graded multi-stage pool lactate test can predict performance in a triathlon swimming segment. This finding is highly useful for coaches as it can help them to obtain a reliable measure of the triathlete's specific capabilities in the swimming leg. [ABSTRACT FROM AUTHOR]

Swimming performance achieved in 50-m, 100-m and 200-m events in each swimming stroke can have an influence on the final performance in individual medley (IM) events. We attempted to quantify the relative contributions of performance in individual stroke events to top-10 world ranked IM competition performance. We examined competition results of top-10 world ranked IM swimmers (90 males and 90 females) between 2012 and 2018. A general linear model was developed to examine association between the 200-m and 400-mIM and predictor variables of competition performance in other 50-m, 100-m, and 200-m events. The main predictor variable for 200-mIM medalist status was having scored more than 900 FINA points in at least one 100-m event. Scoring more than 800 FINA points in at least two 200-mIM events, and more than 900 FINA points in at least one 100-m event, was important for success in the 400-mIM. Top-10 world ranked 200-mIM and 400-mIM swimmers require a world class standard in one or more individual stroke event(s) [ABSTRACT FROM AUTHOR]

The energy dissipation and entropy production by self-propelled microswimmers differ profoundly from passive particles pulled by external forces. The difference extends both to the shape of the flow around the swimmer, as well as to the internal dissipation of the propulsion mechanism. Here we derive a general theorem that provides an exact lower bound on the total, external and internal, dissipation by a microswimmer. The problems that can be solved include an active surface-propelled droplet, swimmers with an extended propulsive layer and swimmers with an effective internal dissipation. We apply the theorem to determine the swimmer shapes that minimize the total dissipation while keeping the volume constant. Our results show that the entropy production by active microswimmers is subject to different fundamental limits than the entropy production by externally driven particles. What is the physical limit on entropy production in a suspension of active microswimmers? In answer to this question, the authors derive a general theorem that provides an exact lower bound on the total, external and internal dissipation by a microswimmer and apply it to optimize swimmer shapes. [ABSTRACT FROM AUTHOR]

Copyright of Research in Sport Education & Sciences is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Galeaspids are extinct jawless relatives of living jawed vertebrates whose contribution to understanding the evolutionary assembly of the gnathostome bodyplan has been limited by absence of postcranial remains. Here, we describe Foxaspis novemura gen. et sp. nov., based on complete articulated remains from a newly discovered Konservat-Lagerstätte in the Early Devonian (Pragian, ∼410 Ma) of Guangxi, South China. F. novemura had a broad, circular dorso-ventrally compressed headshield, slender trunk and strongly asymmetrical hypochordal tail fin comprised of nine ray-like scale-covered digitations. This tail morphology contrasts with the symmetrical hypochordal tail fin of Tujiaaspis vividus , evidencing disparity in galeaspid postcranial anatomy. Analysis of swimming speed reveals galeaspids as moderately fast swimmers, capable of achieving greater cruising swimming speeds than their more derived jawless and jawed relatives. Our analyses reject the hypothesis of a driven trend towards increasingly active food acquisition which has been invoked to characterize early vertebrate evolution. [ABSTRACT FROM AUTHOR]

This article analyzes North Atlantic Treaty Organization (NATO) – Russia dynamics in Eastern Europe, focusing on the competition for influence in Georgia and Montenegro with comparisons to Moldova and Ukraine. Whereas all four countries have expressed a desire to join NATO – and Russia has consistently communicated its disapproval – Moscow has pursued divergent means to curb NATO expansion and escalated with tit-for-tat strategies. We argue that whether Russia deployed military strategies, economic levers, political tactics or covert actions has varied according to its relative power projection capacity along with the responses of NATO and the target countries. Where power projection capacity is greater due to its contiguous geography (Georgia, Ukraine), Russia staged military interventions, and where it was weaker, in non-contiguous countries (Montenegro, Moldova), it resorted to non-military means. Russia may be uniformly opposed to NATO expansion, but its strategies to keep its neighbours out of NATO and in Russia's orbit are contingent upon its relative power. [ABSTRACT FROM AUTHOR]

The study of pace strategy in different environments could help to understand its dependence on athletes' energetic limits or on sport-specific factors. The aim of this study was to analyse the pacing strategy of finalists during seven swimming and running world events held in 2021–2022. The speed of 32 swimmers every 50 m in 1500 m freestyle competitions, and the speed of 55 runners every 100 m in 5000 m track competitions, were analysed. Differences between swimming and running were statistically significant for Total Time (p = 0.00, ES = 1.9), Average Time of splits (p = 0.00, ES = 2.0), Median Time of splits (p = 0.00, ES = 2.0), and Maximal length of split sequences (p = 0.00, ES = 1.3), and non-significantly different for number of Sequences of splits (p = 0.12, ES = 0.5), Percentage of total splits faster than the median speed (p = 0.08, ES = 0.2), Percentage of splits faster than the median speed in the first half (p = 0.16, ES = 0.4) and Percentage of splits faster than the median speed in the second half (p = 0.21, ES = 0.3). In conclusion, despite similar metabolic requirements of 1500 m swimming and 5000 m running, the influence of specific environment and sport type on the pacing strategy of world level competitions seems to be supported. [ABSTRACT FROM AUTHOR]

This research was conducted to determine the skills of freestyle swimming techniques of athletes 10-11 years nemo swallow swimming club in 2022. Participants in this study were Nemo Wallet Swimming Club KU IV athletes aged 10-11 years with 11 athletes. This research is a quantitative descriptive study. The method used is a survey of athletes who perform freestyle swimming by measuring the time taken by athletes in freestyle swimming at a distance of 25 meters. Based on the results of the study, it was obtained that as many as 8 athletes (73%) have excellent freestyle swimming ability, 1 athlete (9%) has good 25 m freestyle swimming ability, 1 athlete (9%) has sufficient freestyle swimming ability, 1 athlete (9%) has less freestyle swimming ability, and 0 athletes (0%) have very less freestyle swimming ability. Based on the results of the research concluded that freestyle swimming skills measured using stopwatches in athletes aged 10-11, from these data can provide an illustration that the category of 25 m freestyle swimming ability in Nemo Wallet Swimming Club athletes is a category (excellent), with a total of 8 athletes. Contributing to further research is conducting research on more intense exercises on freestyle swimming techniques as well as strategies for improving athletes' abilities in freestyle swimming. With this research, it is hoped that it can be used as a reference material for coaches regarding the level of athlete skills. With the discovery of several athletes who have the ability to swim freestyle under the good category, it is necessary to make efforts to improve the ability of athletes in order to achieve the good category [ABSTRACT FROM AUTHOR]

Abstract: Just a few years ago, no one could imagine that ice swimming could evolve into a competitive sport. In the past, people swimming in ice-cold water were called madmen and, at best, were studied as scientific objects. Today regular competitions in ice swimming over different distances (ice mile, ice km, and shorter distances such as 50m, 100m, and 200m), and different disciplines are organized (freestyle, breaststroke, backstroke, butterfly). National championships, as well as continental and world championships, are also held, with new records set regularly. In this overview, we summarize the historical development of ice swimming up to a competitive sport and explore the risks in this nascent sports discipline. [ABSTRACT FROM AUTHOR]

Purpose. There is no consensus in literature data about the influence of biological maturation (BM) on swim performance in young athletes. We analysed the relationship of BM, upper-limb power (ULP), and lower-limb power (LLP) with adolescent athletes' performance in crawl swim. Methods. This observational study determined the BM of 16 competitive swimmers (50% males and 50% females; 12.90 ± 0.88 years) by a mathematical model based on bone age and anthropometric measures. ULP and LLP were established by the horizontal launch test and the vertical and countermovement jump tests on a force platform, respectively. Swim performance was evaluated by the average speed in a 100-m crawl sprint. Results. BM was related to ULP (males: r = 0.76, p = 0.001; females: r = 0.39, p = 0.02), LLP (males: vertical jump r = 0.80, p = 0.02, countermovement jump r = 0.48, p = 0.02; females: vertical jump r = 0.30, p = 0.04, countermovement jump r = 0.80, p = 0.01), and crawl swim performance (males: r = -0.91, p = 0.001; females: r = -0.72, p = 0.04). BM had a 87% contribution to crawl swim performance in males and a 66% contribution in females. ULP and LLP showed < 50% contribution to crawl swim performance in both females and males. Conclusions. BM was associated with crawl swim performance of adolescent athletes of both sexes. BM exhibited a stronger contribution to crawl swim performance than ULP and LLP in adolescent swimmers at the puberty window. [ABSTRACT FROM AUTHOR]

This study aimed to understand whether there are significant differences in stroke kinematics between tiers in female swimmers competing in the four 50 m events of the 2021 European Championships and to understand the speed-time relationship in the four race events per tier. Participants were all female swimmers (backstroke: 78 swimmers; breaststroke: 75 swimmers; butterfly: 74 swimmers; freestyle: 87 swimmers) who participated in the 50 m events at the 2021 LEN European Championships held in Budapest (i.e. heats, semi-finals, and final). For each swimming stroke, swimmers were divided into three tiers (best-performing swimmers, intermedium-performing swimmers, and poorest-performing swimmers). Swimming speed revealed a significant tier effect (p < 0.05) in all race sections for all swimming strokes. The other stroke kinematic variables revealed divergent findings, but the stroke frequency presented an overall tier effect (p < 0.05) across all four swimming strokes. Curve fitting for all swimming strokes and tiers revealed a cubic relationship. Thus, it should be considered that female swimmers who compete in 50 m events in major competitions adopt an all-out strategy. The present data provide coaches with insightful information about the main trend in 50 m sprint events, specifically in each section of the race. [ABSTRACT FROM AUTHOR]

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Human papillomavirus (HPV) infection is the most common sexually transmitted disease worldwide and is associated with negative reproductive outcomes because of which it is recommended to postpone medically assisted reproduction (MAR). This raises major concerns for elder infertile couples. We showed that a hyaluronidase-based sperm washing (IALu) procedure blunted the HPV viral load in semen. Here, were report two cases of couples with long-term idiopathic infertility, ascribed to persistent semen HPV detection, finding a beneficial outcome from the use of IALu protocol applied to intra-uterine insemination (IUI). Case 1: A Caucasian couple (female aged 32, male aged 35), complained of having been attempting pregnancy for 4 years. HPV-DNA (genotypes 51 and 54) was detected on sperms. After a first unsuccessful IUI cycle attempt, using standard swim-up selection of spermatozoa, a second IUI cycle using the IALu procedure was associated with a pregnancy and a successful trimester of gestation. Case 2: A Caucasian couple (female aged 43, male aged 52) complained of having been attempting pregnancy for 3 years and showed the detection of HPV-DNA (genotype 66) on sperms. After a first unsuccessful standard IUI cycle attempt, two further IUI cycles using IALu procedure were pursued. The last cycle was associated with a pregnancy and a successful trimester of gestation. Although preliminary, the IALu procedure is a promising approach for straightforward fertility treatments in cases of recurrent HPV-DNA semen detection, avoiding critical latencies. [ABSTRACT FROM AUTHOR]

While the butterfly stroke has received considerable attention in sports science, the origin of the fastest master butterfly swimmers remains unknown. The present study investigated which geographical locations produce the top-performing master butterfly swimmers within their age groups and gender. A total of 26,512 master butterfly swimmers (11,288 women and 15,224 men) competed in 50 m, 100 m and 200 m races in World Masters Championships held between 1986 and 2019. From each swimmer, the year of competition, first name, last name, age group and distance were recorded. Descriptive data were presented using mean, standard deviation, maximum and minimum values, and/or confidence intervals. The top 10 race times for master butterfly swimming and gender were identified for descriptive purposes. Nationalities were then grouped into six categories: the top five nationalities with the most appearances in the top 10 fastest times in butterfly swimming by distance each year and one group consisting of all other nationalities. In the event of a tie, the nationality with the most participants overall was selected. Generalized linear models (GLMs) with a gamma probability distribution and log link function were used to assess the effect of age groups and gender on swimming time. In summary, Germany had the fastest women butterfly master swimmers across all distances, while the USA had the fastest men butterfly master swimmers for all distances. Men covered all distances faster than women and younger swimmers were quicker than older swimmers. The results of this study can be utilized to determine the countries that produce the most successful master butterfly swimmers, providing a foundation for further research to explore the factors that lead to their success. [ABSTRACT FROM AUTHOR]

The goal of this study was to define the individual model characteristics of lactic acid removal after 200m breaststroke competitive load in a female swimmer in relation to different pool lengths (25m vs. 50m). The second goal was methodological and referred to the presentation of newly applied metrological procedures for the Individual Lactate Recovery Profile modeling. Six races from the competitive season 2021/22 were selected, in which the athlete achieved the most valuable results in relation to the FINA score. To establish the metabolic response of the organism to the competition effort, the method of determining the level of lactate concentration in capillary blood (La in mmol/L) was used. Differences between the mean values of variables were established using ANOVA. The polynomial curve equation function was used to create a blood lactate concentration in a function of recovery time model (La-trecovery). The ANOVA showed that there was no statistically significant difference between the monitored variables and the pool length function (p=.097). The maximum achieved blood lactate concentration in the acute race recovery phase was 13.17 ± 2.81 and 12.08 ± 1.80 mmol/L and the given concentration initially occurred in the time of 240.0 ± 85.6 s and 169.3 ± 79.9 s in the 25 and 50m pool, respectively. In relation to the time of complete passive recovery required to establish acidosis at the level of 2 mmol/L (25 and 50m pool) occurred in 1191.7 ± 481.3 s and 1326.7 ± 405.1 s, while the full index of intensity of blood lactate clearance was 135.7 ± 60.7 s/mmol/L and 124.0 ± 60.7 s/mmol/L for 25m and 50m pool, respectively, although no statistically significant difference was found between the parameters of recovery in relation to pool length. The offered mathematical models enabled a practical individual approach to controlling the specific adaptation to training for achieving a higher competitive level performance. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Medicina do Esporte is the property of Redprint Editora Ltda. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Recently, a commercially available starting 'ledge' designed to reduce foot slippage during the execution of the backstroke start was introduced in competit ive swimming. For the purpose of identifying potential safety consequences, the present study investigated the effect of ledge use on head depths, speeds, and distances in backstroke starts of athletes with no prior or only novice familiarity of the ledge. Competitive backstroke starts were performed with and without ledges by high school-aged (14.5 to 19.2 yr, N = 61) swimmers in 1.52 m of water during a closed testing session. A SIMI Reality Motion System in a calibrated space using three cameras was employed for filming starts. Dependent measures were initia l head height (Yset), distance from wall at entry (Xentry), entry angle (Angleentry), horizontal velocity at head entry (XVelentry), resultant velocity at entry (ResVelentry), maximum depth of the center of the head (Ymhd), resultant velocity at maximum head depth (ResVelmhd), and distance from the wall at maximum head depth (Xmhd). The ledge (L) condition showed significant increases compared to the non-ledge (NL) condition in Xent ry (L 1.61 ± 0.59 m, NL 1.50 ± 0.53 m, p < .001), ResVelent ry (L 3.44 ± 0.97 m·s-1, NL 3.08 ± 1.00 m·s-1, p < .001), Angleent ry (L 43.13 ± 16.97, NL 39.66 ± 18.11, p = .030), Xmhd (L 4.18 ± 0.58 m, NL 4.09 ± 0.63 m, p = .008), and Ymhd (L 0.54 ± 0.21 m, NL 0.49 ± 0.18, p <.001). Backstroke starts using the ledge modestly affected 5 of 8 dependent measures in a direction arguably associated with an increased risk to the novice swimmer. [ABSTRACT FROM AUTHOR]

Sport has long been considered a social phenomenon that addresses all people, being a right recognised at international and national levels. Initially, adapted sport was a means of medical recovery and a means of spending free time in a pleasant way alongside peers with and without disabilities. Subsequently, adapted sport has turned into a means of comparing the motor skills of contestants having the same medical problems during competitions specially organized for these athletes. In recent years, there has been an increase in the number of people with disabilities who play sports but also in the number of non-disabled people who, in one form or another, get involved in adapted sport. In the present study, we aim to highlight the progress achieved in learning and consolidating the swimming technique by an athlete with Down syndrome (aged 25) who has been practising swimming as a recreational activity for 1 year. Based on certain items, the swimming technique was assessed for the three styles known to the athlete, and the means used in the 18 training sessions conducted over 7 months aimed at achieving the goals established at the beginning of the study. Structured, participatory and systematic observation, documentation, mathematical statistics and graphical representation are the methods used to complete the case study. At the end of the study, we could conclude that the athlete has obviously progressed, which is revealed by the assessments carried out. However, the process of learning and improvement had to be continued for the athlete to succeed in swimming correctly and be able to participate in swimming competitions without being disqualified because of technical errors. [ABSTRACT FROM AUTHOR]

Simple Summary: Adolescent swimmers perform a lot of physical training with the aim of improving their performance in the sport. To achieve this goal, their diet must be adequate. In this scenario, studies have suggested that amino acids and acylcarnitines can improve the physical performance of athletes. However, we still do not have information as to whether the same occurs for adolescent swimmers. Thus, we compared amino acids and acylcarnitines present in the blood of adolescent swimmers of both sexes. We also correlated these substances with the performance of athletes. Our results showed that among amino acids and acylcarnitines, only tyrosine was lower in female adolescent swimmers when compared to male athletes. Additionally, significant associations between the female swimmers with tyrosine were observed. Future studies are necessary to understand this relationship, offering new possibilities for nutrition applied to the performance of adolescent swimmers. The main aim of this study was to compare the performance over different distances, the critical velocity (CV), and plasma acylcarnitines/amino acids of male and female adolescent swimmers. Moreover, we applied the complex network approach to identify which molecules are associated with athletes' performances. On the first day under a controlled environment, blood samples were collected after 12 h of overnight fasting. Performance trials (100, 200, 400, and 800-m) were randomly performed in the subsequent four days in a swimming pool, and CV was determined by linear distance versus time mathematical function. Metabolomic analyses were carried out on a triple quadrupole mass spectrometer performing electrospray ionization in the positive ionization mode. No difference was observed between the performance of male and female swimmers. Except for 200-m distance (p = 0.08), plasma tyrosine was positively and significantly associated with the female times during the trials (100-m, p = 0.04; 400-m, p = 0.04; 800-m, p = 0.02), and inversely associated with the CV (p = 0.02). The complex network approach showed that glycine (0.406), glutamine (0.400), arginine (0.335), free carnitine (0.355), tryptophan (0.289), and histidine (0.271) were the most influential nodes to reach tyrosine. These results revealed a thread that must be explored in further randomized/controlled designs, improving the knowledge surrounding nutrition and the performance of adolescent swimmers. [ABSTRACT FROM AUTHOR]

CrossFit® has a unique standard for workout of the day for women and men. Scaling is used to set difficulty levels for women in CrossFit® gyms and competitions. This type of scaling is applied for weightlifting (60–82% of men's load); however, there are usually no differences in difficulty settings for gymnastics and monostructural metabolic conditioning. Performance analysis is essential for every sports discipline, and statistical data comparing men's and women's results from athletics, running, swimming, weightlifting, etc., are available. However, CrossFit® lacks these statistics. The aim of our study was to analyze how the performances of men and women differed at the 2021 CrossFit Games®. Our sample comprised 40 female (age 27.8 ± 5.1) and 40 male participants (age 27.2 ± 3.7) competing in the Rx division. Data obtained from all events were analyzed using effect size and percentage. In 14 out of 15 events, men achieved better results than women. Even with the implementation of scaling, women's results differed by 0.1–33.1% (effect size from small to large). Scaling for women is designed according to general strength and power differences; however, primarily because of anatomic and physiological differences, men attain better results. However, CrossFit Games® events are always unique, and the events rarely repeat; therefore, our study does not provide firm conclusions. As our study is the first to compare CrossFit Games® performance between the sexes, further research is needed. [ABSTRACT FROM AUTHOR]

Magnetically actuated small-scale robots have great potential for numerous applications in remote, confined, or enclosed environments. Multiple small-scale robots enable cooperation and increase the operating efficiency. However, independent control of multiple magnetic small-scale robots is a great challenge, because the robots receive identical control inputs from the same external magnetic field. In this article, we propose a novel strategy of completely decoupled independent control of magnetically actuated flexible swimming millirobots. A flexible millirobot shows a crawling motion on a flat plane within an oscillating magnetic field. Millirobots with different magnetization directions have the same velocity response curve to the oscillating magnetic field but with a difference of phase. We designed and fabricated a group of up to four heterogeneous millirobots with identical geometries and different magnetization directions. According to their velocity response curves, an optimal direction of oscillating magnetic field is calculated to induce a desired velocity vector for the millirobot group, one of which is nonzero and the others are approximately zero. The strategy is verified by experiments of independent position control of up to four millirobots and independent path following control of up to three millirobots with small errors. We further expect that with this independent control strategy, the millirobots will be able to cooperate to finish complicated tasks. [ABSTRACT FROM AUTHOR]

This research is a way to solve a problem that has been presented for several years, on the selection of sports talent in the province of Santi Espíritus, not only in a single category but in the different categories of swimming at provincial and national level: the selection of talent is the most important indicator in swimming and in the different sports without it there would not be high results in competitions, however, despite its importance this is a little researched aspect in the sports sphere of swimming, so this work aims: Systematize the theoretical and methodological aspects of the selection of swimming talent with the intention, since this sport is paramount in the triathlon to go out in the first group of swimming in competitions and a good final result. Experiential Experiential, Historical-Logical and Synthesis Analysis methods were used in this research. This work is useful for swimmers and especially for coaches, both in swimming and triathlon, I know that they will be able to use this document as a working tool or as reference material. Thus, it was concluded that when a proper selection occurs, once the athletes captured for the national team can improve their results from the comparison with reality and that these athletes go to international events the results in swimming are far away and the career of these athletes is lousy, therefore, it is insisted on making a good selection of talents in swimming to be in the elite in the sport of triathlon. [ABSTRACT FROM AUTHOR]

Quantum entanglement brings high-speed and inherently privacy-preserving transmission for information communication in quantum networks. The qubit scarcity is an important issue that cannot be ignored in quantum networks due to the limited storage capacity of quantum devices, the short lifespan of qubits, and so on. In this article, we first formulate the qubit competition problem as the Cooperative-Qubit-Allocation-Problem (CQAP) by taking into account both the waiting time and the fidelity of end-to-end entanglement with the given transmission link set. We then model the CQAP as a Markov Decision Process (MDP) and adopt a Reinforcement Learning (RL) algorithm to self-adaptively and cooperatively allocate qubits among quantum repeaters. Further, we introduce an Active Learning (AL) algorithm to improve the efficiency of the RL algorithm by reducing its trial-error times. Simulation results demonstrate that our proposed algorithm outperforms the benchmark algorithms, with 23.5 ms reduction on the average waiting time and 19.2 improvement on the average path maturity degree, respectively. [ABSTRACT FROM AUTHOR]

We study platform competition in two-sided markets, where consumers value not only the number of providers on the other side of platforms but also their quality. In this context, enhancing provider quality is critical in the competition, and platforms may incentivize high-quality providers to join the platforms with a subsidy. The article examines a two-stage competition game between two platforms who decide their quality-based subsidization strategy and access fees charged to both sides of the platforms. We derive the equilibrium outcomes of the two competing platforms under different subsidization strategy scenarios, and provide insights on the impact of subsidization on platforms' pricing, network sizes, quality, profits, and social welfare in a competitive setting. Our study shows that in competitive environment, subsidization is a double-edged sword that can lead to a prisoner's dilemma for platforms, despite quality improvement. We also find that while subsidization has a positive quality effect that always increases consumer surplus, it may hurt provider surplus if the same-side competition effect among providers is too strong, which negatively affects provider surplus and may drive out low-quality providers under subsidization. As a consequence, the total social welfare also hinges on the provider side competition intensity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the basic conditions required to implement a para-swimming program at the community level. This was undertaken using a qualitative benchmarking approach based on documents/literature and semi-structured interviews with representatives from 13 countries as well as from the International Paralympic Committee's Agitos Foundation. Results indicate that successful community-level para-swimming programs should focus on promoting the inclusion of para-swimmers in swimming clubs, with integration being a step towards inclusion. The basic conditions needed to do so include facilities and logistics, financial, and human resource needs. Findings also highlight the importance of the local context and culture. Based on these findings, guidelines are offered for implementing a para-swimming program at the community-level, notably: following inclusion principles, following a sport development pathway, and developing a stakeholder network. Funding remains an overarching barrier that must be addressed for such a program to be successful. [ABSTRACT FROM AUTHOR]

(1) Background: The aim of the present research is to describe the kinematic characteristics of push start in competitive swimmers and to examine the role of the push start sub-phases on the overall start performance. (2) Methods: Seventy-four swimmers (33 males and 41 females) of national and international level performed one 25 m trial at maximum velocity with a push start at butterfly, backstroke and/or front-crawl techniques and were filmed with two sequential underwater cameras during the glide, leg kicking, transition and surface swimming phases. (3) Results: Backstroke starts showed greater emersion distances but slower times to 10 m than the remaining strokes. Distances and average velocities in each of the start sub-phases predicted the overall push start performance (times to 10 m) on the butterfly (R2: 0.50) and backstroke (R2: 0.58) strokes, with the velocity of the leg kicking phase having a statistical effect on both regression analysis and the glide and transition phases in backstroke. (4) Conclusions: Push starts performed in a dorsal body position seemed to present kinematic differences with ventral techniques and a greater technical complexity with all glide, leg kicking and transition sub-phases meaningfully impacting the overall push start performance. This should be considered when executing the daily training repetitions with swimmers in water. [ABSTRACT FROM AUTHOR]

Microorganisms can efficiently navigate in anisotropic complex fluids, but the precise swimming mechanisms remain largely unexplored. Their dynamics is determined by the interplay between multiple effects, including the fluid's orientation order, swimmer's undulatory gait and the finite length. Here, we extend the numerical study of the two-dimensional undulatory motions of a flexible swimmer in lyotropic liquid-crystalline polymers (LCPs) by Lin et al. (J. Fluid Mech., vol. 921, 2021, p. A25) to the scenario of arbitrary swimming directions with respect to the nematic director. The swimmer is modelled as a nearly inextensible yet flexible fibre with imposed travelling-wave-like actuation. We investigate the orientation-dependent swimming behaviours in nematic LCPs for an infinitely long sheet (i.e. Taylor's swimming sheet model) and finite-length swimmers. We demonstrate that the swimmer must be sufficiently stiff to produce undulatory deformations to gain net motions. Moreover, a motile finite-length swimmer can reorient itself to swim parallel with the nematic director, due to a net body torque arising from the asymmetric distribution of the polymer force along the body. [ABSTRACT FROM AUTHOR]