Observation system for the technical-tactical analysis of judo by the Rio 2016 Olympic champions.

An observational methodology system has been designed which allows the observation and analysis of the technical-tactical behaviour and interaction of judokas during competition. The observation instrument (JUTACTIC) is composed of 8 fixed criteria that provide information related to the competition and the competitors and 13 variable criteria that, throughout the intrasessional monitoring of each combat, allow the behaviour displayed by both judokas and their interaction to be recorded. From an observational sample consisting of matches from the Rio 2016 Olympic champions and the corresponding samples made using the LINCE PLUS software, evidence of validity, reliability, generalizability and applicability of the observation system is provided. The content validity of the observation instrument has been endorsed by a panel of experts (n = 11). Intra and inter-observer reliability has been guaranteed from the results obtained in the Fleiss Kappa and the Krippendorff Alpha. The generalizability analysis with the design structure [Category] [Participants] / [Matches] has confirmed that around seven matches are needed to accurately analyse the behaviour of the competitor under study. The practical application possibilities of the observation instrument has been shown with an example of the results obtained and the regular behaviour structures detected (T-patterns) using the THEME software.

Female-biased birth sex ratio in a female dispersal primate suggests local resource competition.

Group living may entail local resource competition (LRC) which can be reduced if the birth sex ratio (BSR) is biased towards members of the dispersing sex who leave the group and no longer compete locally with kin. In primates, the predicted relationship between dispersal and BSR is generally supported although data for female dispersal species are rare and primarily available from captivity. Here, we present BSR data for Phayre's leaf monkeys (Trachypithecus phayrei crepusculus) at the Phu Khieo Wildlife Sanctuary, Thailand (N = 104). In this population, nearly all natal females dispersed, while natal males stayed or formed new groups nearby. The slower reproductive rate in larger groups suggests that food can be a limiting resource. In accordance with LRC, significantly more females than males were born (BSR 0.404 males/all births) thus reducing future competition with kin. This bias was similar in 2-year-olds (no sex-differential mortality). It became stronger in adults, supporting our impression of particularly fierce competition among males. To better evaluate the importance of BSR, more studies should report sex ratios throughout the life span, and more data for female dispersal primates need to be collected, ideally for multiple groups of different sizes and for several years.

Diving into a pool of data: Using principal component analysis to optimize performance prediction in women's short-course swimming.

This study aimed to optimise performance prediction in short-course swimming through Principal Component Analyses (PCA) and multiple regression. All women's freestyle races at the European Short-Course Swimming Championships were analysed. Established performance metrics were obtained including start, free-swimming, and turn performance metrics. PCA were conducted to reduce redundant variables, and a multiple linear regression was performed where the criterion was swimming time. A practical tool, the Potential Predictor, was developed from regression equations to facilitate performance prediction. Bland and Altman analyses with 95% limits of agreement (95% LOA) were used to assess agreement between predicted and actual swimming performance. There was a very strong agreement between predicted and actual swimming performance. The mean bias for all race distances was less than 0.1s with wider LOAs for the 800 m (95% LOA -7.6 to + 7.7s) but tighter LOAs for the other races (95% LOAs -0.6 to + 0.6s). Free-Swimming Speed (FSS) and turn performance were identified as Key Performance Indicators (KPIs) in the longer distance races (200 m, 400 m, 800 m). Start performance emerged as a KPI in sprint races (50 m and 100 m). The successful implementation of PCA and multiple regression provides coaches with a valuable tool to uncover individual potential and empowers data-driven decision-making in athlete training.

The Unification of Evolutionary Dynamics through the Bayesian Decay Factor in a Game on a Graph.

We unify evolutionary dynamics on graphs in strategic uncertainty through a decaying Bayesian update. Our analysis focuses on the Price theorem of selection, which governs replicator(-mutator) dynamics, based on a stratified interaction mechanism and a composite strategy update rule. Our findings suggest that the replication of a certain mutation in a strategy, leading to a shift from competition to cooperation in a well-mixed population, is equivalent to the replication of a strategy in a Bayesian-structured population without any mutation. Likewise, the replication of a strategy in a Bayesian-structured population with a certain mutation, resulting in a move from competition to cooperation, is equivalent to the replication of a strategy in a well-mixed population without any mutation. This equivalence holds when the transition rate from competition to cooperation is equal to the relative strength of selection acting on either competition or cooperation in relation to the selection differential between cooperators and competitors. Our research allows us to identify situations where cooperation is more likely, irrespective of the specific payoff levels. This approach provides new perspectives into the intended purpose of Price's equation, which was initially not designed for this type of analysis.

Overuse injury and affects in competitive sport: A prospective longitudinal study.

Overuse injuries, which have a high prevalence in sport, are suggested to result in different affective responses in comparison to traumatic injuries. Affects may also reciprocally act as risk factors for overuse injury. The aim of this study was to examine the associations between overuse injury and affects within a longitudinal follow-up design. Competitive athletes (N = 149) of various sports and levels of competition completed the Positive and Negative Affect Schedule (PANAS) and the Oslo Sports Trauma Research Centre Overuse injury questionnaire (OSTRC-O) once a week over 10 consecutive weeks. Bivariate unconditional latent curve model analyses with structured residuals were performed to evaluate the associations within and across weeks between OSTRC-O severity score and affects. Results indicated that OSTRC-O severity score and positive affects (PA) had a statistically significant negative within-week relation (r = -24.51, 95% CI = [-33.9, -15.1], p < 0.001). Higher scores of overuse injury were significantly related to lower levels of PA across weeks (ß = -0.02, 95% CI = [-0.04, -0.001], p = 0.044), while the reciprocal effect of PA on overuse injury was not significant (ß = -0.13, 95% CI = [-0.52, 0.26], p = 0.51). No statistically significant association was observed between OSTRC-O severity score and negative affects, neither within nor across weeks. Our findings suggest that overuse injury may have adverse psychological consequences on the long run through lessened PA and address the need for providing sustainable psychological support focusing upon such PA when working with athletes experiencing overuse injury.

Energy intake, hydration status, and sleep of world-class male archers during competition.

BACKGROUND: Nutritional intake and sleep, play an important role for recovery and performance in elite sport but little work has been undertaken in archery. The present study aimed to assess energy intake (EI), hydration status, and sleep parameters in world-class male archers over the course of a four-day competition. METHODS: Results, Conclusions Six male, elite-standard archers participated in the study and measurements of hydration status, EI, competition load, and sleep were recorded throughout each day of competition. RESULTS: Daily energy, carbohydrate, and protein intake ranged between 2,563 and 3,986 kcal, 4 and 7.1 g/kg BM, 2.2 and 3.6 g/kg BM per day, respectively. Thus, archers practiced elements of periodized nutrition such that energy and carbohydrate intake was greater on the high-volume competition days (i.e. days 1 and 3; more numbers of arrows, longer duration, and walking distance) in comparison to low-volume days (days 2 and 4) over the tournament (all p > 0.01). Additionally, urine specific gravity was higher after waking, compared to pre- and post-competition, and before bed (all p < 0.05). This indicates that archers were euhydrated pre- and post-competition and before bedtime, while they were slightly hypohydrated after waking up. Sleep data show that disturbances were kept to a minimum. CONCLUSIONS: Collectively, archers appear capable of periodizing their nutritional intake according to daily physical loading during a tournament whilst, staying euhydrated and maintaining sleep quality. In part, such data can help to explain why these archers experience a sustained level of success.

Is competitive ability the key adaptation to benign environments? Revisiting experiments on closely related species of tidal plants.

A central goal in biology is to understand which traits underlie adaptation to different environments. Yet, few studies have examined the relative contribution of competitive ability towards adaptive divergence among species occupying distinct environments. Here, we test the relative importance of competitive ability as an adaptation to relatively benign versus challenging environments, using previously published studies of closely related species pairs of primarily tidal plants subjected to reciprocal removal with transplant experiments in nature. Subordinate species typically occupy more challenging environments and showed consistent evidence for adaptation to challenging conditions, with no significant competitive effect on non-local, dominant species. In contrast, dominant species typically occupy relatively benign environments and performed significantly better than non-local, subordinate species that faced competition from the dominant species. Surprisingly, when the two species were not allowed to compete, the subordinate species performed as well as the dominant species in the benign environments where the subordinate species do not occur. These results suggest that competitive ability is the most important adaptation distinguishing the species that occupy relatively benign environments. The limited scope and number of suitable experimental studies encourage future work to test if these results are generalizable across taxa and environments.

An EEG Dataset of Neural Signatures in a Competitive Two-Player Game Encouraging Deceptive Behavior.

Studying deception is vital for understanding decision-making and social dynamics. Recent EEG research has deepened insights into the brain mechanisms behind deception. Standard methods in this field often rely on memory, are vulnerable to countermeasures, yield false positives, and lack real-world relevance. Here, we present a comprehensive dataset from an EEG-monitored competitive, two-player card game designed to elicit authentic deception behavior. Our extensive dataset contains EEG data from 12 pairs (N = 24 participants with role switching), controlled for age, gender, and risk-taking, with detailed labels and annotations. The dataset combines standard event-related potential and microstate analyses with state-of-the-art decoding approaches of four scenarios: spontaneous/instructed truth-telling and lying. This demonstrates game-based methods' efficacy in studying deception and sets a benchmark for future research. Overall, our dataset represents a unique resource with applications in cognitive neuroscience and related fields for studying deception, competitive behavior, decision-making, inter-brain synchrony, and benchmarking of decoding frameworks in a difficult, high-level cognitive task.

Testing general sociocultural and coach-related appearance pressures as the factors associated with disordered eating in competitive female athletes participating in various sports.

The aim of the present study was to test the sociocultural Petrie and Greenleaf's (2007) model of disordered eating (DE) in competitive female athletes. Specifically, we tested a model of general sociocultural and coach-related pressures towards body weight and appearance of female athletes as the factors associated with athletes' DE through the mediators such as internalization of appearance ideals and overweight preoccupation. 515 athletes participated in this study. The mean age of the sample was 19.0 ± 5.9 years. Athletes were provided with study measures on general sociocultural and coach-related appearance and body weight pressures, internalization of appearance ideals, overweight preoccupation and DE. Path analyses showed that general sociocultural pressures were associated with DE directly and through internalization of appearance ideals and overweight preoccupation. Pressures from coaches were associated with DE through overweight preoccupation and through the internalization of appearance ideals and overweight preoccupation. The models were invariant across body weight sensitivity in sports and age groups. These results inform DE prevention for female athletes. It is important to increase resistance to sociocultural pressures and pressures from coaches in DE prevention programmes for female competitive athletes of all ages and participating in sports irrespective of sports group (weight-sensitive or less weight-sensitive).

Association between match-related physical activity profiles and playing positions in different tasks: A data driven approach.

Assessing the intensity characteristics of specific soccer drills (matches, small-side game, and match-based exercises) could help practitioners to plan training sessions by providing the optimal stimulus for every player. In this paper, we propose a data analytics framework to assess the neuromuscular or metabolic characteristics of a soccer-specific exercise in relation with the expected match intensity. GPS data describing the physical tasks' external intensity during an entire season of twenty-eight semi-professional soccer players competing at the fourth Italian division were used in this study. A supervised machine-learning approach was tested in order to detect difference in playing positions in different sport-specific drills. Moreover, a non-supervised machine-learning model was used to profile the match neuromuscular and metabolic characteristics. Players' playing positions during matches and match-based exercises are characterised by specific metabolic and neuromuscular characteristics related to tactical demands, while in the small-side game these differences are not detected. Additionally, our framework permits to evaluate if the match performance request is mirrored during training drills. Practitioners could evaluate the type of stimulus performed by a player in a specific training drill in order to assess if they reflect the matches characteristics of their specific playing position.

The perspective of current and retired world class, elite and national athletes on the inclusion and eligibility of transgender athletes in elite sport.

There has been limited empirical study allowing athletes to voice their opinions on transgender participation in elite sport. This study surveyed 175 national, elite and world class athletes eligible to compete in the female category regarding transgender inclusion and eligibility. The study compared current Olympic versus current Olympic Recognised sports, elite versus world class, and current versus retired Olympic sport athletes. Most athletes favoured biological sex categorisation (58%) and considered it unfair for trans women to compete in the female category, except for precision sports. This view was held most strongly by world class athletes regarding their own sport (77% unfair, 15% fair). For trans men inclusion in the male category, most athletes considered it fair, except for Olympic sport athletes regarding contact sports (49% unfair, 27% fair) and sports heavily reliant on physical capacity (53% unfair, 29% fair). Notwithstanding those views, athletes (81%) believed sporting bodies should improve inclusivity for transgender athletes. Opinion varied somewhat according to career stage, competitive level and sport type. Nevertheless, athletes in the present study favoured categorisation by biological sex and did not support trans women eligibility for the female category in sports reliant on performance-related biological factors that differ between sexes.

Higher-order species interactions cause time-dependent niche and fitness differences: Experimental evidence in plant-feeding arthropods.

Species interact in different ways, including competition, facilitation and predation. These interactions can be non-linear or higher order and may depend on time or species densities. Although these higher-order interactions are virtually ubiquitous, they remain poorly understood, as they are challenging both theoretically and empirically. We propose to adapt niche and fitness differences from modern coexistence theory and apply them to species interactions over time. As such, they may not merely inform about coexistence, but provide a deeper understanding of how species interactions change. Here, we investigated how the exploitation of a biotic resource (plant) by phytophagous arthropods affects their interactions. We performed monoculture and competition experiments to fit a generalized additive mixed model to the empirical data, which allowed us to calculate niche and fitness differences. We found that species switch between different types of interactions over time, including intra- and interspecific facilitation, and strong and weak competition.

On being unpredictable and winning.

In theory, it can be strategically advantageous for competitors to make themselves unpredictable to their opponents, for example, by variably mixing hostility and friendliness. Empirically, it remains open whether and how competitors make themselves unpredictable, why they do so, and how this conditions conflict dynamics and outcomes. We examine these questions in interactive attacker-defender contests, in which attackers invest to capture resources held and defended by their opponent. Study 1, a reanalysis of nine (un)published experiments (total N = 650), reveals significant cross-trial variability especially in proactive attacks and less in reactive defense. Study 2 (N = 200) shows that greater variability makes both attacker's and defender's next move more difficult to predict, especially when variability is due to occasional rather than (in)frequent extreme investments in conflict. Studies 3 (N = 27) and 4 (N = 106) show that precontest testosterone, a hormone associated with risk-taking and status competition, drives variability during attack which, in turn, increases sympathetic arousal in defenders and defender variability (Study 4). Rather than being motivated by wealth maximization, being unpredictable in conflict and competition emerges in function of the attacker's desire to win "no matter what" and comes with significant welfare cost to both victor and victim. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Performance and micro-pacing in sprint cross-country skiing: A comparison of individual time-trial and head-to-head race formats.

This study compared performance strategies and sub-technique selection in cross-country skate skiing sprint races, specifically individual time-trial (ITT) and head-to-head (H2H) formats. Fourteen male cross-country skiers from the Chinese national team participated in the FIS-sanctioned sprint race day. GNSS and heart rate sensors recorded positioning, skiing speeds, heart rate, sub-technique usage, and skiing kinematics. Statistical parametric mapping (SPM) was used to determine the course positions (clusters) where instantaneous skiing speed was significantly associated with section time. One-way analyses of variance were used to examine differences between the ITT and H2H. H2H race speeds were 2.4 ± 0.2% faster than the ITT race (p < 0.05).Variations in sub-technique and skiing kinematics were observed between race formats, indicating different strategies and tactics employed by athletes. SPM identified specific clusters (primarily uphill) where the fastest athlete gained significant time over the slowest. The greatest time gains were associated with higher G3 sub-technique usage and longer G3 cycle length on steep uphill terrain (9-13% gradients). Integrating SPM analyses and sub-technique assessments can help optimise performance and tactics in sprint races. This study enhances our understanding of cross-country skiing dynamics and performance variations among elite competitors.

Effect of Level of Competition and Drill Typology on Internal and External Load in Male Volleyball Players During the Preseason Period.

PURPOSE: This study aimed at evaluating the effect of level of competition and drill typology on loads during the preseason period in male volleyball players. METHODS: Internal (percentage of peak heart rate [HR] and summated HR zone) and external (PlayerLoad per minute, total and high accelerations per minute [tACCmin and hACCmin], decelerations per minute [tDECmin and hDECmin], and jumps per minute [tJUMPmin and hJUMPmin]) loads were monitored across a 5-week preseason period in 12 Division 1 (age: 22.5 [3.9] y; stature: 188 [6.2] cm; body mass: 85 [11.6] kg; training experience: 9.4 [4.2] y) and 12 Division 2 (age: 20.7 [2.9] y; stature: 186 [6.2] cm; body mass: 77.8 [9.6] kg; training experience: 5.6 [2.3] y) male volleyball players. Furthermore, differences in load were assessed for each drill typology (warm-up, conditioning, technical, tactical, and integral). RESULTS: No effects (P > .05) of level of competition on the internal (except for summated HR zone, P = .05) and external loads (except for tJUMPmin, P = .002) were found. Differently, drill typologies showed an effect (P < .001) on all the investigated internal- and external-load measures. The main post hoc results revealed higher (P < .05) percentage of peak HR, summated HR zone, PlayerLoad per minute, and tACCmin in warm-up and conditioning drills, while higher (P < .05) hDECmin and hJUMPmin were found in tactical and integral drills. CONCLUSIONS: These results suggest that volleyball coaches use warm-up and conditioning drills when aiming at increasing the internal loads, PlayerLoad per minute, and tACCmin, while tactical and integral drills should be preferred to enhance the number of hDECmin and hJUMPmin.

Peak Performance: Characteristics and Key Factors in the Development of the World Top-8 Swimmers Based on Longitudinal Data.

PURPOSE: This study aimed to investigate the peak performance characteristics of the world top-8 swimmers and the key factors involved in the journey toward achieving better peak performance. METHODS: The results of the world top-8 swimmers from 2001 to 2022 were collected from the World Aquatics performance database. Progression to peak performance was tracked with individual quadratic trajectories (1191 cases). Utilizing k-means clustering to group competitive feature variables, this study investigated key developmental factors through a binary logistic regression model, using the odds ratio (OR) to represent whether a factor was favorable (OR > 1) or unfavorable (OR < 1). RESULTS: Significant differences (P < .001) in the peak age between men (23.54/3.80) and women (22.31/4.60) were noticed, while no significant differences (P > .05) in the peak-performance window for both sexes appeared. Peak performance occurred at later ages for the sprint for both sexes, and women had a longer duration in peak-performance window for sprint (P < .05). Peak-performance occurred at later ages for the breaststroke and butterfly for both sexes (P < .05). Binary logistic regression revealed that high first-participation performance (OR = 1.502), high major-competition performance (OR = 4.165), early first-major-competition age (OR = 1.441), participation frequency above 4 times/year in both phase 2 (4.3-8.0 times/y, OR = 3.940; 8.1-20.0 times/y, OR = 5.122) and phase 3 (4.1-7.5 times/y: OR = 5.548; 7.7-15.0 times/y: OR = 7.526), and a career length of 10 years or more (10-15 y, OR = 2.102; 16-31 y, OR = 3.480) were favorable factors for achieving better peak performance. CONCLUSIONS: Peak performance characteristics varied across sex, swimming stroke, and race distance in the world top-8 swimmers. Meanwhile, the research indicated that certain specific developmental factors were key conditions for the world top-8 swimmers to achieve better peak performance in the future.

Understanding feeding competition under laboratory conditions: Rohu (Labeo rohita) versus Amazon sailfin catfish (Pterygoplichthys spp.).

Competitive interactions between species is widely prevalent within the animal world. In this manuscript, we attempted to understand feeding competitions between the Amazon sailfin catfish, an invasive species introduced globally, and rohu, a keystone species native to several countries within southeast Asia. We used two different size classes of each species, large-size having total length (TL, from snout tip to caudal fin) of 15-20 cm and fingerling having TL<6 cm, and feeding duration was used as a proxy to understand competition. Our results demonstrated that feeding durations of large-size rohu were either similar or significantly (P<0.05) higher in presence of catfish when compared to trials in presence of conspecifics, indicating that large-size rohu is not a weak competitor. However, feeding durations of fingerling rohu was significantly (P<0.05) reduced in presence of both large-size and fingerling catfish, when compared to trials in presence of conspecifics. Moreover, fingerling rohu also displayed freeze (alarm) behavior in presence of the catfish. Interestingly, presence of rohu had no significant (P>0.05) impact on feeding durations of catfish. Overall, the study demonstrated that invasive catfish may behaviorally outcompete fingerling rohu, thus, threatening the sustenance of a species that is native to several freshwaters around the globe.

Analysis of the competitive demands in 7-a-side football players with cerebral palsy

Inertial devices allow for obtaining a large amount of information related to external load during official competitions. The study aimed to analyse fatigue in different functional classification players of a Football 7-a-side for people with cerebral palsy or acquired brain injury team, considering the movements, speed changes and impacts during the 2020 Spanish National League matches (n = 12). The analyzed independent variables were the different functional classifications (FC) of the players, FC1, FC2 and FC3, and also time. Regarding the dependent variables, kinematic objective external load (displacements and speed changes), and neuromuscular objective external load (impacts) were considered. This study is an empirical investigation that follows an associative and descriptive analysis, ANOVA test, and a Bonferroni post hoc test (multiple comparisons) were carried out between the external load variables based on FC and time. The results show differences between FC1 for people with greater functional limitation to FC3, and athletes with less functional limitation depending on the time of the match. FC2 players presented greater competitive demands in specific moments of the match than FC3 athletes because of the requirements of the competition. Furthermore, evaluating different FC players with inertial devices in official competitions provides useful information regarding the demands of Fa7PC players, which is fundamental for daily training tasks management and injury risk prevention in Fa7PC. The large number of variables associated with inertial devices data collection during training sessions and official competitions in Fa7PC allows us to understand the demands of CP players, as well as how to make decisions during the games and training process, namely for reducing the injury risk. (AU)