Search Results (196)

This paper investigates the inherent conflict between individual and collective interests within multi-coalition games. Unlike traditional noncooperative frameworks where players solely optimize a collective objective, our model incorporates individual player preferences, naturally formulating a constrained multi-objective game. To address this, we introduce an endogenous preference weight factor to scalarize the multi-objective problem into a tractable single-objective game. Furthermore, we propose distributed game strategies equipped with predefined-time convergence to compute the Nash equilibrium of the multi-coalition game, alongside the weight factors. Subsequently, consensus protocols and gradient descent methods are synthesized to locate the weighted Nash equilibrium of the scalarized game. The rigorous predefined-time convergence of the proposed algorithm is established via Lyapunov stability theory. Finally, numerical simulations validate the efficacy and superiority of the proposed framework. Full article

This study aimed to describe and compare warm-up (WU) demands of different protocols (with ball, without ball and pre-match) on female football players. Twenty-two players belonging to the same team were monitored throughout 12 training weeks using global navigation satellite system technology sampling at 10 Hz. The variables used were duration, total distance, distances covered within 0–45%, 45–60%, 60–85%, and 85–100% of individual maximum speed, maximum speed, maximum acceleration, maximum deceleration, number of accelerations of magnitudes between 1 and 2 m/s², 2 and 3 m/s², 3 and 4 m/s², and above 4 m/s², number of decelerations of magnitudes between −1 and −2 m/s², −2 and −3 m/s², −3 and −4 m/s², and below −4 m/s², Player Load, and TRIMP Edwards. A linear mixed model was carried out for each variable in order to analyze the differences between WU protocols. The main results were that pre-match WU showed higher values in the following variables: (1) duration; (2) distances covered within 60–85% and 85–100% of individual maximum speed; (3) maximum speed, acceleration and deceleration; (4) number of accelerations of magnitudes between 2 and 3 m/s² and between 3 and 4 m/s², and more decelerations of magnitudes between −2 and −3 m/s², −3 and −4 m/s² and below −4 m/s²; and, (5) TRIMP Edwards. These findings underscore the importance of WU design in preparing female football players for high-intensity match demands and contribute to the development of specific WU strategies for them. Full article

Background: Nutrition and sleep are critical determinants of athletic performance and recovery. Direct comparative research between endurance and strength–power athletes remains limited. This study aimed to evaluate and compare nutritional knowledge, dietary habits, sleep quality, and Body Mass Index between ultramarathon runners and American football players, as well as to explore independent predictors of sleep quality. Methods: A cross-sectional study was conducted among 231 male athletes. To address group size disparity and mitigate statistical bias, a random undersampling technique was applied to create a balanced cohort of 86 athletes comprising 43 ultramarathon runners and 43 American football players. Nutritional parameters were assessed using the Kom-PAN questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Between-group comparisons were performed using the Mann–Whitney U test with False Discovery Rate correction. An integrated multiple regression model was constructed to identify predictors of global sleep quality. Results: Ultramarathon runners demonstrated significantly better overall sleep quality (p = 0.026) and higher nutritional knowledge (p < 0.001) compared to American football players. Differences in adherence to pro-healthy and non-healthy dietary patterns were not statistically significant after False Discovery Rate correction. The integrated multiple regression model revealed that the athletic discipline was the primary independent predictor of global sleep quality (p = 0.001), while dietary variables did not exhibit a significant independent effect. Furthermore, higher Body Mass Index was independently associated with better sleep scores within the multivariate model (p = 0.008). Conclusions: Significant sport-specific differences exist in BMI, nutritional knowledge, and sleep quality. Global sleep quality appears to be primarily associated with the specific physiological and environmental demands of the athletic discipline rather than individual dietary factors, which were not independently significant in the multivariable model. These findings suggest that recovery strategies in strength–power athletes may require a broader, multifactorial approach beyond nutritional education alone. Full article

Backgrounds: The aim of this pilot study was to evaluate the hierarchical contribution of individual genetic polymorphisms to the variability of autonomic regulation parameters and respiratory function in athletes of different sport specializations using Classification and Regression Tree (CRT) analysis. Methods: The study included athletes divided into two groups: hockey players (n = 48) and martial artists (n = 43). Heart rate variability (LF, HF) parameters and spirometric indices (FEV₁) were assessed. Genetic analysis included 8 single nucleotide polymorphisms (SNPs): IL6 rs1800795, VDR rs731236, KCNJ11 rs5219, ADRB2 rs1042713, ADRB2 rs1042714, TRHR rs16892496, MSTN rs1805086, UCP3 rs1800849. Results: In martial artists, the main predictors were genes responsible for adrenoreceptor sensitivity (ADRB2) and neuroimmune interactions (IL6). In hockey players, the most significant predictors were genes involved in muscle growth (MSTN), energy metabolism (UCP3), and neuroendocrine regulation (TRHR). These findings indicate that similar resting HRV parameters in athletes from different sports may be associated with different genetic polymorphisms, reflecting sport-specific physiological adaptations to training loads. Conclusions: The results highlight the sport-specific nature of genetic determinants of autonomic regulation. In martial artists, genes related to the immuno-adrenergic axis (IL6, ADRB2) appear to play a dominant role, whereas in hockey players neuroendocrine, muscle-metabolic, and mitochondrial factors (TRHR, MSTN, UCP3) demonstrate greater influence. The observed interactions between genotypes and FEV₁ emphasize the importance of transitioning from generalized approaches toward personalized monitoring strategies in sports science. Full article

Introduction: Monitoring training load is essential in elite soccer to optimize performance and reduce injury risk. The training-to-match load ratio (TMr) has emerged as a useful metric to contextualize training demands relative to competitive match exposure. The objective of this study was to compare daily and accumulated TMr between starters and non-starters over a professional season, considering microcycle day and playing position. Methods: Twenty players (Tier 3) from a professional team were monitored during a full competitive season (30 microcycles; 144 training sessions; 30 matches). External load variables, namely total distance (TD), high-speed distance (HSD), sprint distance (SPD), high metabolic load distance (HMLD), acceleration (ACC) and deceleration (DCC), were collected using 10 Hz GPS devices (STATSports). Daily and microcycle TMr were calculated relative to each player’s maximal match value registered during a full competitive period. Linear mixed-effects models examined the effects of starting status, microcycle day, and playing position. Results: Linear mixed models revealed significant three-way interactions (status × day × position) for locomotor variables: TD (F = 3.36, p < 0.001), HSD (F = 2.49, p < 0.001), and SPD (F = 3.37, p < 0.001). Starters accumulated higher loads on match day, whereas non-starters showed higher TMr on MD + 1 and MD + 2. Position-specific differences emerged during acquisition sessions (i.e., MD − 5 to MD − 3), particularly for wide midfielders (WMs) and central defenders (CDs). No significant three-way interactions were observed for ACC, DCC, or HMLD absolute loads (p > 0.05), nor for any accumulated microcycle TMr metrics (p > 0.05). Conclusions: TMr effectively differentiates preparation strategies between starters and non-starters. Although “top-up conditioning” sessions increase early-week relative loads for non-starters, position-specific variations–particularly in mechanical variables during acquisition sessions–highlight the need for individualized load prescription. Full article

Base running performance in baseball depends on the ability to efficiently transition between linear and curvilinear sprinting; however, current assessment approaches provide limited insight into how speed is developed, maintained, or lost across these phases. This perspective presents a methodological framework for using GPS technology to enhance the analysis and interpretation of base running performance through segment-specific velocity and time diagnostics. GPS data were collected during 54.7 m linear sprints and home-to-second-base curvilinear sprints in three high-school baseball players with differing performance profiles. Sprint paths were divided into standardized linear (L1–L4) and curvilinear (C1–C4) segments, allowing examination of speed changes between successive phases to identify acceleration, maintenance, and deceleration patterns. Comparative case analyses illustrate how athletes differ in their ability to negotiate the curve around first base, reaccelerate toward second base, and maintain speed under increasing curvilinear demands. In addition, a base running efficiency ratio (BREr) is introduced to quantify how effectively linear sprint capacity is preserved during curvilinear base running, both globally and across early and late phases of the sprint. The three players’ data illustrated that GPS-derived velocity–time profiles may provide useful insights into individual running strategies, path selection, and segment-specific performance limitations that are not captured by traditional timing methods. Rather than establishing normative benchmarks, this paper emphasizes the applied value of GPS technology as a diagnostic tool to potentially inform individualized assessment and monitoring in applied settings related to linear and curvilinear sprint performance in baseball. Full article

This study aimed to identify distinct lactate kinetic phenotypes in professional soccer players using unsupervised machine learning and determine their relationship with maximal running velocity (V_max) through explainable artificial intelligence methods. A total of 361 professional male soccer players from the First Division participated in the study. Incremental treadmill tests measured lactate concentrations at five standardized velocities, alongside VO_2max, V_max, lactate threshold (LT), and anaerobic threshold (AT) parameters. Three distinct lactate kinetic phenotypes emerged: Economical Aerobic (n = 216), Balanced Metabolic (n = 19), and High Producer (n = 126). The Economical Aerobic phenotype demonstrated superior performance metrics compared to High Producer (V_max: 15.85 ± 0.85 km/h; VO_2max: 56.20 ± 4.26 mL/kg/min; p < 0.001). Initial multicollinearity assessment revealed notable collinearity among all 10 candidate predictors (VIF > 10; maximum VIF = 10.75 for V_AT), necessitating rigorous feature selection. Ridge regression with 4 selected features (V_AT, VO_2max, 9.5 km/h lactate, 14 km/h lactate) achieved moderate but statistically significant predictive performance: 10-fold cross-validation R²= 0.392 ± 0.147 (permutation test p = 0.001). Standardized coefficients identified V_AT (β = 0.399) as the dominant predictor, followed by VO_2max (β = 0.253), 9.5 km/h lactate (β = 0.107), and 14 km/h lactate (β = −0.066). Lactate kinetic phenotyping reveals position-independent metabolic profiles with potentially meaningful performance associations in professional soccer. The Economical Aerobic phenotype demonstrates performance advantages associated with superior anaerobic threshold capacity. These exploratory findings suggest that individualized training strategies based on metabolic phenotype rather than playing position alone warrant further investigation, with potential applications for talent identification, training periodization, and return-to-play protocols pending prospective validation. Full article

Real-time strategy (RTS) games provide a cognitively demanding and ecologically valid context for investigating workload dynamics in human–computer interaction (HCI). This multimodal study (HRV, NASA-TLX, behavior, interviews) examined multitasking, visual complexity, and decision pressure in 36 novice RTS players. High multitasking significantly increased subjective workload (total raw-TLX: from 22.50 ± 14.65 to 36.47 ± 20.19, p < 0.001) and prolonged completion time (from 317.17 ± 37.26 s to 354.92 ± 50.70 s, p < 0.001). Decision pressure elevated subjective workload (total raw-TLX: from 20 to 28, p = 0.008) without affecting performance. Although HRV did not consistently differentiate experimental conditions at the group level, it showed stable individual-level associations with perceived workload—both in expected directions (e.g., LF power positively correlated with total raw-TLX across four experiments, r = 0.28–0.53, all p < 0.05) and in inverse relationships that deviate from conventional stress models (e.g., stress index negatively correlated with total raw-TLX, r = −0.34 to −0.40, all p < 0.01). These findings suggest that autonomic responses in complex interactive environments may reflect dynamic engagement processes rather than uniform stress activation, supporting multimodal cognitive load assessment and offering transferable insights for interface design and workload evaluation in demanding HCI contexts. Full article

Soccer is an intermittent sport that requires complex and well-adjusted physiological responses from athletes. The training load allows athletes to optimize physical adaptations and reduces the risk of musculoskeletal injuries. In women’s soccer, the implementation of load control and individualization strategies has shown promise for enhancing anaerobic performance and injury prevention. This study aimed to compare the performance levels of professional women’s soccer players before and after the implementation of relative external load (RELC) for training prescription. Twenty-seven female professional soccer athletes (mean age 29.4 ± 6.2 years) were evaluated. Metrics such as total distance, sprint distance, number of sprints, accelerations, and decelerations were collected using the GPS-based device Catapult One (Catapult). Athletes were assessed in two games, with 6 months’ difference between matches: Game 1, without RELC implementation, and Game 2, with RELC. Significant differences were found between both periods. Sprint distance increased from 391 m to 450 m (+15%, d = 0.49, p ≤ 0.05), and sprint count increased from 14 to 17 (+21%, d = 0.35, p ≤ 0.05), showing improved performance related to increased physical output in the second half of the season. These findings suggest potential performance improvements associated with individualized load control over the course of the season. Full article

Background/Objectives: Simulation-based education often lacks personalization, focusing on technical competence rather than individual student profiles. This protocol describes a study designed to evaluate whether adapting gamified narratives to nursing students’ personality profiles has the potential to support academic performance in obstetrics. This study aims to validate the integration of psychometric profiling and AI as a sustainable strategy for personalized clinical training. Methods: A cluster-randomized controlled longitudinal pilot trial will be conducted at the University of Atlántico Medio. The protocol has been submitted for registration at ClinicalTrials.gov (Registration Pending). Thirty-eight second-year nursing students meeting inclusion criteria (excluding repeaters or those with prior specialized training) will be assigned by natural practice to either a control group (generic gamification) or an experimental group (gamification adapted according to Player Personality and Dynamics Scale profiles using AI-generated content). The intervention comprises four clinical simulation sessions focusing on pregnancy and childbirth, which are managed via the Wix platform. The primary outcome is academic performance, measured as “Learning Gain” (post-test scores minus pre-test scores). Secondary outcomes include student satisfaction measured via the Gameful Experience Scale. Data will be analyzed using Mann–Whitney U tests to compare overall efficacy and intragroup evolution. To minimize observer bias, knowledge assessments will utilize automated, objective scoring, and participants will be blinded to the study hypothesis. Expected Outcomes: The study aims to establish the technical and pedagogical feasibility of integrating AI-adapted narratives into nursing curricula. It is anticipated that the personalized approach will show positive trends in learning gains and engagement patterns, providing a baseline for larger multicenter trials. Conclusions: This protocol presents a framework for “Precision Education” in nursing, shifting from “one-size-fits-all” simulations to student-centered adaptive training. The use of Generative AI makes such personalization sustainable and cost-effective for health science faculties. Full article

Background: Congested tournament schedules impose substantial physiological stress in team sports; however, the integrated endocrine and inflammatory responses to real competitive match load in female handball players remain insufficiently characterized. Objective: This study aimed to characterize the acute biochemical responses, including hormonal, inflammatory, muscle damage, and bone metabolism markers, elicited by competitive tournament load in female handball players and to provide practical insights for optimizing recovery strategies and load management during short-term competitive periods. Methods: In a pre–post study design, venous blood samples were collected from competitive female athletes (n = 8; age 20.83 ± 2.93 years) before the first match and after the fourth consecutive match of an official university qualification tournament. Biochemical analyses included cortisol, insulin, IL-6, creatine kinase (CK), IGF-1, irisin, lactate dehydrogenase (LDH), osteocalcin, and testosterone. Pre-to-post changes were assessed using paired t-tests and effect sizes. Results: Tournament load induced substantial multisystem physiological perturbations. Significant increases were observed in cortisol (p < 0.001), insulin (p = 0.044), IL-6 (p < 0.001), CK (p < 0.001), and osteocalcin (p = 0.005), indicating activation of the hypothalamic–pituitary–adrenal axis, systemic inflammation, muscle membrane disruption, and enhanced bone turnover. Conversely, IGF-1 (p < 0.001) and testosterone (p = 0.004) significantly decreased, reflecting suppression of anabolic signaling and a shift toward a catabolic hormonal environment under cumulative match stress. LDH significantly decreased (p = 0.002), while irisin showed no significant change (p > 0.05). Conclusions: These findings demonstrate that congested tournament schedules provoke an integrated endocrine–inflammatory stress response in female handball players. Importantly, the observed anabolic–catabolic imbalance highlights the need for individualized recovery strategies, optimized load management, and adequate recovery periods to mitigate maladaptation and reduce injury risk during short-term competitive tournaments. Full article

The experience of being acknowledged by one’s coach has been highlighted as important, but the pedagogical approach of being seen has not been empirically explored within sport. The purpose of this study was to investigate the extent to which young Norwegian football players experienced being seen by their head coach in football, as well as to examine gender differences in these experiences with a previous validated questionnaire, originally developed for students within physical education, but adapted for football. Using a list of all teams participating in the Boys 19 league and the Girls 17 league in Trøndelag County, 7 boys’ teams and 9 girls’ teams were randomly selected. A total of 212 players (107 boys and 105 girls) responded to the questionnaire. Participants’ ages ranged from 15 to 19 years. The results showed that 83 percent of the boys and 87 percent of the girls agreed (slightly to strongly) that they experienced being seen by their head coach during training or football matches. There were no significant gender differences regarding this experience, nor in four of the five underlying factors contributing to being seen. However, a significant gender difference was found according to good dialogue, where girls scored higher than boys when rating their coaches. Finally, the results indicated that players perceived their coach as most competent in facilitating good dialogue, and least competent in involving players in assessment and goal setting, and in creating opportunities for players to showcase themselves. Based on these results, coaches should actively create opportunities for dialogue before, during, and after training or matches, signaling openness through body language, tone, and availability so players feel comfortable initiating conversation. Coach education programs should emphasize communication strategies that promote psychological safety and belonging, including practical steps such as brief one-on-one conversations during warm-up or cool-down to help players feel seen without disrupting team flow. The gender difference in good dialogue highlights the importance of tailoring communication strategies to individual needs while ensuring that dialogue opportunities are accessible to all players. Full article

This study investigates the performance characteristics of U18 semi-professional soccer players by examining both technical load (TL) and physical load (PL) variables across various playing positions during the 2021/2022 Spanish Football U18 National League Championship. Methods: Principal Component Analysis (PCA) was employed to simplify the dataset, which comprised 246 match records from 49 athletes (mean age 17.9 ± 0.7 years; height ~177.6 ± 6.3 cm; body mass ~72.0 ± 7.2 kg) across ten matches. This analytical approach aimed to facilitate a deeper understanding of player performance dynamics. Results: Kaiser–Meyer–Olkin (KMO) values varied across positions (technical load: 0.20–0.93; physical load: 0.27–0.91). This indicates acceptable sampling adequacy for several positional models, but low adequacy for others; therefore, results for positions with low-KMO values should be interpreted cautiously. Factor analysis for both technical and physical load variables identified two components each, explaining substantial total variance (technical load: 63.75–86.65%; and physical load: 71.74–88.92% across position), with significantly high factor correlations (p < 0.001). The findings further indicate that players occupying defensive positions, such as goalkeepers and center-backs, generally exhibit lower levels of physical intensity and technical engagement compared to their counterparts in more dynamic roles, including full-backs, wingers, and forwards. The latter groups demonstrate higher involvement in high-intensity running and offensive actions. Conclusions: The observed performance patterns highlight the necessity for tailored training programs that align with the specific demands of each playing position. This approach is expected to optimize individual player performance and enhance overall tactical efficiency. Furthermore, the study underscores the importance of developing individualized conditioning strategies that address the unique physical and technical requirements inherent to each role on the field. This analytical approach using PCA provides a more structured and data-driven understanding of these positional differences, reinforming the need for tailored training programs and individualized conditioning strategies. Full article

Objectives: This study compares linear sprint force–velocity (F–v) mechanical variables between elite Under-19 (U19) academy players and senior professional players. Methods: Thirty-eight senior players (SP; mean age 24.5 ± 4.3 y) and 214 U19 academy players (YP; mean age 17.4 ± 0.5 y) from 14 first-division club academies were tested during October 2023 using a motorized resistance device (1080 Motion). The following F–v variables were assessed: maximal theoretical force (F₀, N·kg⁻¹), maximal theoretical velocity (v₀, m·s⁻¹), maximal ratio of horizontal-to-resultant force (RF_max, %), and decrease in the ratio of forces (DRF, %). Between-group comparisons were performed using the t-test, and Cohen’s d effect sizes were reported. Results: Senior players outperformed U19 players across all F–v variables. F₀ exhibited a mean difference = 0.220 N·kg⁻¹, with a 95% confidence interval (CI) [0.056, 0.384], p = 0.0166, and d = 0.46. v₀ exhibited a mean difference = 0.560 m·s⁻¹, with a 95% CI [0.410, 0.710], p < 0.0001, and d = 1.07. RF_max exhibited a mean difference = 1.470%, with 95% CI [0.830, 2.110], p = 0.0003, and d = 0.69. DRF exhibited a mean difference = 0.260%, with a 95% CI [0.103, 0.417], p = 0.0013, and d = 0.53. Conclusions: U19 players demonstrated lower F₀, lower v₀, and reduced mechanical effectiveness compared with senior players. Regular monitoring of F–v profiles and individualized training interventions (force- or velocity-targeted) may be useful for training and monitoring strategies aimed at supporting physical preparation during the transition to senior soccer. Full article

Background/Objectives: The primary outcome of this 8-week randomized, controlled, parallel trial was to assess longitudinal shifts in gut microbiota structure and predicted metabolic potential in 45 elite football players following protein supplementation. Methods: Participants combined resistance training with daily intake (30 g) of whey protein concentrate (WPC), pea protein isolate (PPI), rice protein isolate (RPI), or a plant-protein blend (MIX). For the acquisition of prokaryotic metataxonomic data, the V3–V8 region of the 16S rRNA gene was sequenced using Oxford Nanopore Technology (ONT). Functional potential was inferred through the MACADAM database and STAMP software. Strict dietary monitoring and gravimetric adherence checks were performed to isolate the intervention effect. Results: While microbial alpha-diversity indices (Chao1, Shannon, Simpson) remained stable across all groups, significant source-specific shifts in taxonomic structure and predicted metabolic activity were identified. Whey protein concentrate (WPC) was associated with an increase in Bacteroidetes abundance and greater balance within the microbial community structure, whereas pea protein isolate (PPI) and the MIX correlated with reduced fermentative bacteria and elevated taxa potentially involved in cadaverine biosynthesis. Rice protein isolate (RPI) supplementation was associated with a higher predicted representation of taxa involved in succinate-to-butyrate fermentation pathways. These functional markers and differential responses of selected bacterial groups to particular protein types were observed. Conclusions: The data indicate complex interactions between supplement type, exposure duration, and microbiome response, underscoring the necessity for individualized dietary recommendations and supplementation strategies to optimize gut health and training adaptation in professional football players. Full article