Variations in strength-speed-power performance across the season: do true changes occur in elite rugby players?

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether "true changes" occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period (P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, "true changes" in strength-power-(but not in speed-) related qualities were consistently observed over the competitive season.

Space and players' number constrains the external and internal load demands in youth futsal.

Introduction: The aim of this study was to analyze the effects of space and number of players manipulation on the external and internal load demands of youth futsal athletes. Methods: Forty-two male U17 players (age = 15.62 ± 0.58 years) from three futsal teams participated in the study. In this cross-sectional study that lasted 8-week, the player's sample practiced six futsal tasks (T1-T6) and a futsal game played under the official rules (T7). From T1-T6, two task constraints were manipulated: (i) the number of players and, (ii) the space of play. The WIMU PRO™ Ultra-Wideband (UWB) tracking system was used to measure the external and internal load during the futsal tasks. External load was quantified using kinematic and mechanical variables extracted from positional data and, the internal load was quantified using Heart rate (HR) and rating of perceived exertion (RPE). Repeated measures ANOVA was used for comparison purposes. Results: In general, the results showed high external (total distance, distance 18.1-21, above 21 Km/h, and high intensity acceleration and deceleration, p < 0.001) and internal load (heart rate average and rating of perceived exertion, p < 0.001) in the tasks with low number of players and high area. In relation to the match, the tasks with small relative area per player (GK + 2 vs. 2 + GK and GK + 3 vs. 3 + GK in 20 × 20 m) promoted low external load. Conclusion: It was concluded that increasing the relative area by reducing the number of players involved in the tasks in the form of small-sided games (GK + 2 vs. 2 + GK and GK + 3 vs. 3 + GK), in relation to the futsal game (GK + 4 vs. 4 + GK), can be considered a pedagogical strategy to increase the external and internal load demands of young futsal players.

Influence of contextual factors on match running performance of starters and non-starters in elite youth male soccer players.

This study investigated the effects of match location, quality of opposition (classified into: strong [1st to 4th position]; intermediate [5th to 15th position]; weak [16th to 20th position]), and match outcome on the match running performance of starters and non-starters from a top elite Brazilian soccer team. Absolute measures were calculated using total distance, high-speed (19.8-25.2 km·h-1), sprinting (≥ 25.2 km·h-1), total distance high-acceleration (> 2m·s2), and deceleration (< -2m·s2) were recorded by GPS units from a sample of young soccer players (N = 25) in a total of 17 matches. Relative measures were calculated by dividing absolute measures by the total duration of the matches. Non-starters covered greater total distance (p = 0.02), sprinting (p = 0.02), high-acceleration and deceleration (p = 0.04), sprinting distance relative per minute played (p = 0.005), and high-acceleration and deceleration relative per minute played (p < 0.001) when the team plays at home, strong opponents, and wins the matches. Starters covered greater total distance in high-speed running (p = 0.04), high-acceleration and deceleration (p = 0.03), and high-speed running relative per minute played (p = 0.04) when the team plays strong opponents and wins the matches. These findings highlight the impact of contextual factors during matches on the locomotor performance of young soccer players.

Recovery in elite youth basketball players: The responsiveness of the psychophysiological measurements and the role of testosterone concentration.

This study investigated the recovery responses to the Total Quality Recovery (TQR), Well-Being questionnaire (WBQ), and Heart Rate (HR) responses to Submaximal Running Test (SRT), and the influence of salivary testosterone concentration (TEST) on these responses in 25 elite youth (U15) male basketball players. TQR, WBQ, and HR measurements were assessed after 48 hours of rest (T1), 24 hours after the 1st day of training (T2) and 24 hours after the 2nd day of training (T3). Salivary sampling was conducted at T1 and T3. A significant decrease was observed for TQR (F = 4.06; p = 0.01) and for WBQ (F = 5.37; p = 0.008) from T1 to T3. No difference among the three-time points was observed for HR and HR Recovery, and the TEST concentration did not influence the results. These results show that TQR and WBQ are sensitive to acute transient alterations in training loads (TL) and may be utilized to monitor recovery in elite youth basketball players. The HR related measurements presented limited responsiveness, and the TEST seems not to influence the recovery of these players who are competing at highest performance level.

Is the Field Test of FUT-SAT a Better Experimental Design to Identify the Specific Characteristics of Tactical Performance according to Youth Male Soccer Players' Positional Roles?

This study aimed to compare soccer players' tactical performance according to their positional roles in the field test of FUT-SAT. The sample consisted of 54 male players from elite youth clubs (Medellín-Colombia), U16 and U17 categories. Participants trained five times per week (Tier 3). We used the System of Tactical Assessment (FUT-SAT), which evaluates tactical behaviour and performance through core tactical principles of soccer. The field test is structured in a numerical configuration of a goalkeeper + 3 players vs. 3 players + a goalkeeper played during 4 min on a playing field 36 m long by 27 m wide. All teams were structured with one player in each positional role (one defender, one midfielder, and one forward).To determine the differences between the positional roles, the following factors were analysed: the number of actions, the percentage of correct actions, the place of action related to the principles, and the Tactical Performance Index of core tactical principles. A total of 2891 tactical actions distributed in nine games were analysed. A Kruskal-Wallis test for the independent groups (defenders, midfielders, and forwards) or a one-way ANOVA was used. There was no difference in soccer players' tactical performance and behaviour between players of different positional roles in the field test of FUT-SAT.Therefore, teams need to be evaluated with the system of play with players in all field sectors in medium or large sided games. The system of play can be chosen according to the category given that competitions are held in reduced spaces and with fewer players.

Innovative integration: optimizing performance through warm-up and photobiomodulation in high-intensity test.

We investigated whether the application of photobiomodulation therapy (PBMT) immediately after a standardized warm-up (WU + PBMT) or traditional PBMT (no pre-warming) would influence performance in intermittent testing and intensity variables. In a counterbalanced randomized crossover design, twelve female futsal players (mean age: 23.9 ± 3.8 years) attended four sessions. Each session involved either a standardized warm-up or maintaining seated rest for five minutes. Subsequently, PBMT or placebo (with the PBMT device turned off) was applied, followed by the YoYo Intermittent Recovery Level 1 test (YYIR1) during which we assessed heart rate, rating of perceived exertion, and blood lactate levels. The performance in YYIIR1 was superior (p = 0.02) in the WU + PBMT condition (440.0 ± 59.0 m) compared to the WU + Placebo (353.3 ± 94.7 m), and placebo alone (no warm-up) (325.0 ± 67.2 m). We conclude that a combination of a specific warm-up before PBMT application improves high-intensity intermittent performance in amateur female futsal players without affecting intensity variables.

Effects of Contextual Variables on Match Load in a Professional Soccer Team Attending to the Different Season Periods.

This study aimed to analyze the effects of contextual variables (i.e., match location and match outcome) and season periods on match load (i.e., internal and external load) in professional Brazilian soccer players. Thirty-six professional players from the same soccer team participated in this study. The season was split into four phases: matches 1-16 (i.e., Phase 1 = P1); matches 17-32 (i.e., Phase 2 = P2); matches 33-48, (i.e., Phase 3 = P3); matches 49-65 (i.e., Phase 4 = P4). Considering match outcome, when the team wins, Cognitive load, Emotional load, and Affective load were significantly higher in away vs. home matches (p < 0.05). Considering season phases, in P3, Mental Fatigue was significantly higher in drawing than in losing matches (p < 0.05). Additionally, considering the match outcome, when the team lost, Total Distance (TD)/min and TD > 19 km·h-1/min were significantly lower in P1 than P2 (p < 0.001), P3 (p < 0.001), and P4 (p < 0.001). These results suggest to strength and conditioning coaches the need to consider the outcome and location of the previous game when planning the week, as well as the phase of the season they are in to reduce fatigue and injury risk.

Is There a Relationship Between Birth Quartile and Vertical Jump Performance Among Young Male Elite Volleyball Athletes?

Vertical jump is an important skill that influences volleyball performance. In this study, we analyzed the relationship between vertical jump performance and birth quartile of Brazilian male youth volleyball players. We calculated chi-square goodness-of-fit tests to compare the athletes' birthdate distributions in quarters of their birth years (Q1, Q2, Q3, and Q4) according to player age categories (U17, U18, U19, and U21). We calculated one-way ANOVAs to compare spike jump and block jump heights of players born in different quarters of the same year. Overall, we found a relative age effect (i.e., more players with birth dates early in the birth year) in U17 (p < .001), U18 (p < .001), U19 (p < .001), and U21 (p = .04). Regarding vertical jump performance, U18 athletes born in Q2 reached higher spike jump heights (p = .006) and block jump heights (p = .002) than athletes born in Q4, and U19 athletes born in Q1 reached higher block jump heights than athletes born in Q3 (p = .049). There were no significant differences in vertical jump performance across birth quartiles among U17 and U21 athletes. Thus, a relative age effect was present in all age categories but not always reflected in vertical jump performance. Volleyball coaches and policymakers are still advised to employ strategies to ensure fairer opportunities for players born later in the year of their eligibility dates, as we found RAE to be sometimes, but not always, related to higher spike or block jump heights even among these older adolescents and young adult athletes.

Sand and grass surfaces are equally effective in promoting positive adaptations in the sprint performance of elite young soccer players.

This study compared the effects of two sprint-jump training programmes, performed on either sand or grass surfaces, on the sprint and jump performance of elite young soccer players over an 8-week training period. Fifteen under-20 soccer players were randomly allocated to the sand (n = 7) or grass (n = 8) group. Athletes performed 12 training sessions, comprising vertical and horizontal jump exercises, and linear and change-of-direction (COD) sprint drills. Pre- and post-measurements were completed in the following order: vertical jump, sprint speed at 10 m and 17 m, curve sprint (CS), and modified Zigzag COD tests. Between-group differences were determined using a two-way ANOVA with repeated measures and effect sizes (ES). No improvements in jump performance were found in either group. Significant increases were observed in the sand group for acceleration in 0-10 m and for 10- and 17-m linear sprint velocity (ES = 1.15, 1.16, and 1.81, respectively; P < 0.05). In contrast, no significant differences were detected for acceleration and linear sprint velocity in the grass group, comparing pre- and post-tests (ES ranging from 0.01 to 0.47; P > 0.05). Both sand and grass groups revealed similar increases in the CS and COD velocities after the training period (ES ranging from 0.98 to 1.93; P < 0.05). In conclusion, sprint-jump training programmes performed on both grass and sand surfaces elicited significant improvements in CS and COD performances, whereas acceleration and linear sprint velocity increased only in the sand group, after a short-term training period. The sand training surface was proven to be a practical strategy to improve sprint performance in all its forms in soccer players, which is of great interest and importance for coaches and sport scientists working in elite soccer.

Change-of-Direction and Deceleration Deficits in National-Team Female Rugby Sevens Players: Interrelationships and Associations With Speed-Related Performance.

PURPOSE: To investigate the relationships between a series of direct and indirect measures of linear and multidirectional speed performance in elite female rugby sevens players. METHODS: Nineteen players from the Brazilian national team performed 40-m linear sprint and 505 change-of-direction (COD) tests on the same day. Based on the linear sprint and COD test performances, the COD deficit (CODD) and deceleration deficit (DD) were also obtained. A Pearson product-moment correlation analysis was used to determine the relationships between linear sprint and COD-derived variables. RESULTS: Linear sprint and 505 COD velocities were not significantly associated (P > .05). Large to very large significant associations (r values ranging from .54 to .78; P < .05) were detected between linear sprint velocity for the different distances tested (10, 15, 30, and 40 m) and CODD. The COD velocity presented a very large inverse significant correlation with CODD and DD (r = -.77 and -.79 respectively; P < .05). A large and significant correlation was identified between CODD and DD (r = .79; P < .05). CONCLUSIONS: Significant associations were observed between linear sprint and CODD, suggesting that faster players are less efficient at changing direction. No relationship was found between sprint velocity and DD, highlighting the independent nature of linear sprints and deceleration capabilities. A comprehensive and detailed analysis of multidirectional speed performance should consider not only linear sprint and COD performances but also complementary COD-derived variables such as the CODD and DD.

Los Músculos Isquiosurales y su Capacidad Profiláctica sobre la Translación Tibial Anterior en Lesión de Ligamento Cruzado Anterior: Una Revisión Sistemática / The Hamstrings Muscles and their Prophylactic Capacity on Anterior Tibial Translation in Anterior Cruciate Ligament Injury: A Systematic Review

La ruptura de ligamento cruzado anterior (LCA) es la lesión de rodilla más común que se trata de una reconstruc- ción quirúrgica. El objetivo principal de esta revisión fue analizar la importancia de la función de los músculos isquiosurales como factor de riesgo de posibles lesiones de LCA. Se llevó a cabo siguiendo las normas Preferred Reported Item for Systematic Reviews and Meta- analyses (PRISMA). La fuente de la recopilación de datos fue la consulta directa de las bases de datos Pubmed, Sportdiscus, Web of Science y Scopus. Para la recuperación documental, se utilizaron varias palabras clave y se evaluó la calidad de los estudios que fueron seleccionados mediante la escala PEDro. Los déficits de la función muscular en los músculos isquiosurales se han relacionado con una mayor translación tibial anterior y, como consecuencia, un incremento del estrés tensional sobre el LCA entre los 10° y 45° de flexión de rodilla. Una co-activación de los músculos isquiosurales con el músculo cuádriceps femoral puede ser de gran ayuda para reducir los factores de riesgo de la lesión LCA.

SUMMARY: Anterior cruciate ligament (ACL) rupture is the most common knee injury to undergo surgery in the sports setting. The main objective of this review was to analyze the importance of hamstring function as a risk factor for potential ACL injury. It was conducted following the Preferred Reported Item for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The source of data collection was direct consultation of the Pubmed, Sportdiscus, Web of Science and Scopus databases. For documentary retrieval, several key words were used and the quality of the studies that were selected was assessed using the PEDro scale. Muscle function deficits in the hamstrings have been related to increased anterior tibial translation and, as a consequence, increased tensional stress on the ACL between 10° and 45° of knee flexion. A co-activation of the hamstrings with the quadriceps may be helpful in reducing the risk factors for ACL injury.

Young Basketball Players' Multiple Object Tracking Skills Were Unaffected by Stroop-Induced Mental Fatigue.

We aimed to examine the acute effect of mental fatigue on young basketball players' three-dimensional multiple object tracking (3D-MOT) skills. Our participants were 12 adolescent basketball players (M age = 16.66, SD = 1.87 years; M years of practice = 2.66, SD = 1.07 years). In nine lab visits, we used visits 1 to 7 to familiarize participants with 3D-MOT, a subjective scale of mental fatigue, and a Stroop task involving mental set shifting. In the last two visits, participants performed in both experimental (EXP) and control (CON) conditions that were presented in randomized order. In the EXP condition, participants performed 3D-MOT pre- and post-60 minutes of induced mental fatigue; in the CON condition, they watched a documentary. After each condition, B participants performed the National Aeronautics and Space Administration Task Load Index (NASA-TLX). 3D-MOT performance measures were the "score" and "fastest trial score success." The response time on the Stroop tasks increased throughout the mental fatigue inducement in the experimental condition (p = .0037). The NASA-TLX responses were higher following the EXP condition than following the CON condition for mental demand, temporal demand, and performance (all ps < .05). Still, there were no significant EXP versus CON differences on the 3D-MOT performance indicators.

Is Binge Drinking Associated With Specific Types of Exercise and Free Time Sports? A Pooled Analysis With 718,147 Adults.

OBJECTIVE: To verify the association between exercise and free time sport types and binge drinking in a large sample of adults. METHODS: Data of 718,147 adults from the "Surveillance of Risk and Protection Factors for Chronic Diseases by Telephone Survey" were used. We described the demographic and behavioral variables, and negative binomial regression analyzed the association between exercise and free time sport types and binge drinking adjusted by demographics variables, body mass index status, and television time. RESULTS: Outdoor walking/running was the most common exercise reported (20.0%, 95% confidence interval [CI], 19.8%-20.2%), followed by team sports (8.1%; 95% CI, 8.0%-8.2%) and strengthening (8.0%; 95% CI, 7.9%-8.1%). The prevalence of binge drinking for each exercise and free time sport type ranged from 6.9% (water aerobics) to 31.9% (team sports). Participants engaging in strengthening (prevalence ratio = 1.12; 95% CI, 1.04-1.21, P = .002) and team sports (prevalence ratio = 1.11; 95% CI, 1.07-1.17, P < .001) were more likely to binge drink more frequently in the past 30 days than inactive participants. CONCLUSIONS: It appears that the participants' profile plays an important role in the underlying social context of this association. Participants with more frequent strengthening and less frequent team sports practice, who were primarily younger and single, were more likely to binge drink frequently.

Análisis de los polimorfismos ECA y ACTN3 con la agilidad en seleccionados nacionales de deportes de conjunto de Costa Rica. Estudio piloto / ACE and ACTN3 polymorphisms analysis on agility test in national players in team sports of Costa Rica. Pilot study / Análise dos polimorfismos ECA e ACTN3 com agilidade em jogadores esportivos selecionados da seleção costarriquenha. Estudo piloto

Resumen: Objetivo: Analizar las diferencias de los polimorfismos de los genes ECA y ACTN3 en el rendimiento de una prueba de agilidad en jugadores élite de deportes colectivos pertenecientes a selecciones nacionales de Costa Rica. Metodología: Se contó con una muestra de 33 jugadores hombres, de deportes colectivos (fútbol sala, rugby, voleibol y balonmano). Para la evaluación de la agilidad se utilizó el test de Illinois. Se realizaron dos visitas, en la primera se obtuvo muestras de células por medio de un enjuague y en la segunda se aplicó la prueba de agilidad. Se utilizó la prueba de Chi-cuadrado (X2) para conocer las diferencias entre las frecuencias de los polimorfismos de los genes ECA y ACTN3 y el tipo de deporte. Resultados: La mayor distribución de los polimorfismos del gen ECA, de jugadores de selecciones nacionales de deportes de conjunto, se encuentra en el ID (X2= 6.87, p= .334) y en ACTN3 el RX (X2= 6.33, p= .388). Además, tampoco se encontraron diferencias significativas entre el tiempo efectuado en el test de Illinois y los polimorfismos del gen ECA (F= 2.150, p= .134), de igual forma para los polimorfismos del gen ACTN3 (F= .950, p= .339). Conclusiones: Los polimorfismos de los genes ECA y ACTN3 no se relacionaron estadísticamente con el tipo de deporte colectivo. La agilidad no se ve asociada por un tipo de polimorfismo, lo que indica que, de forma independiente al gen, esta cualidad física se puede entrenar y generar buenos resultados en la población en general.

Abstract: Objective: To analyze the differences in the polymorphisms of the ACE and ACTN3 genes on agility test performance in elite players of collective sports from National teams of Costa Rica. Methods: a sample of 33 male team sports players (futsal, rugby, volleyball, and handball). All subjects were tested with the Illinois Agility Test. Two days of measurements were made; on the first day, cell samples were obtained and on the second day, the agility test was applied. The Chi-square test (x2) was used to determine the differences between the frequencies of the polymorphisms of the ACE and ACTN3 genes and the type of sport. Results: The highest distribution of polymorphisms of the ECA gene of players from national teams of collective sports was found in the ACE ID (X2 = 6.87, p = .334), and in ACTN3 the RX (X2 = 6.33, p =. 388). Furthermore, no significant relationship was found between the Illinois test performance and the polymorphisms of the ECA gene (F = 2,150, p = .134). Conclusions: The ACE and ACTN3 genes polymorphisms were not statistically related to the type of team sport. Agility is not associated with the type of polymorphism, which indicates that regardless of the gene, this physical quality can be trained and generate good results in the general population.

Resumo: Objetivo: analisar as diferenças dos polimorfismos dos genes ECA e ACTN3 na realização de um teste de agilidade em jogadores de elite de equipes esportivas pertencentes a equipes nacionais costarriquenhas. Metodologia: foi utilizada uma amostra de 33 jogadores de futebol masculino (futsal, rúgbi, vôlei e handebol). O teste de Illinois foi usado para avaliar a agilidade. Foram feitas duas visitas; na primeira foram obtidas amostras de uma célula por lavagem e na segunda foi aplicado o teste de agilidade. O teste qui-quadrado (X2) foi usado para determinar as diferenças entre as frequências dos polimorfismos dos genes ECA e ACTN3 e o tipo de esporte. Resultados: A maior distribuição de polimorfismos do gene ECA em jogadores de equipes nacionais de esportes coletivos é encontrada no ID (X2= 6,87, p= 0,334) e no ACTN3 no RX (X2= 6,33, p= 0,388). Além disso, não foram encontradas diferenças significativas entre o tempo gasto no teste de Illinois e os polimorfismos do gene ECA (F= 2,150, p= 0,134), assim como para os polimorfismos do gene ACTN3 (F= 0,950, p= 0,339). Conclusões: Os polimorfismos dos genes ECA e ACTN3 não estavam estatisticamente relacionados com o tipo de esporte coletivo. A agilidade não está associada pelo tipo de polimorfismo, indicando que, independentemente do gene, essa qualidade física pode ser treinada e gerar bons resultados na população em geral.

The load-velocity relationship in the jump squat exercise.

The purpose of this study was to test the load-velocity relationship in the jump squat (JS) exercise using three different velocity parameters (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]). Twenty-six male rugby union players (24.3 ± 3.9 years; 1.81 ± 0.09 m; 101.3 ± 15.4 kg) performed a progressive loading test in the JS with loads corresponding to 20, 40, 60, and 80% of the half-squat 1RM (equivalent to 24, 46, 70, and 94% of the estimated JS-1RM). MV, MPV, and PV were continuously recorded during all attempts using a linear velocity transducer. Linear regression models were used to determine the relationships between JS loads and MV, MPV, and PV. Bar-velocity outputs demonstrated high levels of consistency and reliability (coefficient of variation ≤ 5% and intraclass correlation coefficient ≥ 0.90). The predictive power of MV, MPV, and PV were ≥ 91%, for all tested variables (P < 0.0001). The equations and bar-velocity values provided in this study can be used by coaches to precisely determine and prescribe JS training loads, from verylight to heavy loading conditions (i.e., ~20-100% JS 1RM).

Speed-Related Abilities Are Similarly Improved After Sled Training Under Different Magnitudes of Velocity Loss in Highly Trained Soccer Players.

PURPOSE: We examined the effects of two 8-week resisted-sprint training programs under different magnitudes of velocity loss (VL) on the speed-related performance of highly trained soccer players. METHODS: Twenty-one soccer players (age: 25.9 [5.4] y) were randomly assigned to 1 of 2 groups: (1) the "moderate-load group," players who trained with sled loads that induced 15%VL relative to unloaded sprint velocity (n = 11); and (2) the "heavy-load group," players who trained with sled loads that induced 40% VL relative to unloaded sprint velocity (n = 10). Linear sprint (10 m), curve sprint, change-of-direction speed, resisted-sprint performance at 15% VL and 40% VL, and vertical jumping ability were tested pretraining and posttraining. A 2-way repeated-measures analysis of variance was used to test for differences between groups. In addition, percentage changes were calculated for speed-related abilities and compared with their respective coefficients of variation to determine whether individual changes in performance were greater than the test variance (ie, "true change"). RESULTS: A main effect of time was detected for 10-m sprint, curve sprint, change-of-direction speed, and 15% VL and 40% VL resisted-sprint times, with significant decreases in sprint times (P = .003, P = .004, P = .05, P = .036, and P = .019, respectively). Jump variables did not change significantly over time. There were no group-by-time interactions for any tested variable (P > .05), but the "true change" analysis revealed meaningful individual changes in both groups. CONCLUSIONS: Both moderate- and heavy-sled loading conditions may optimize the development of speed-related abilities in highly trained soccer players. Nevertheless, resisted-sprint training responses may differ meaningfully when assessed on an individual basis.

The emergence of critical incidents in Rugby Union matches using Markov chain analysis.

During a rugby match, teams are continually trying to cause instabilities of different magnitudes on each other. Once a perturbation occurs, a phase transition emerges. Markov chain analysis has the potential to investigate emerging patterns in rugby union. This study examined the probability of a critical incident (CI; penalties and tries) occurring during Rugby Union matches, and whether differences would exist between winning and losing. The Markov chain analysis was used to identify the probability of a transition from a game state to a further state, due to the analysis of the preceding state. A game phase was defined as a technical and tactical match action which occurred between two consecutive advantage lines. Contingency tables were assembled from 280 phases registered during 11 matches of Brazilian Rugby Union XV A Series Championship. The results showed that previous technical and tactical actions made from rucks had the highest probability of generating a transition phase leading to a CI. The results suggest that the winning teams adopt a more flexible approach to the environmental changes that occur throughout a game and demonstrated more flexibility during transitional state occurrences, with higher variability in technical and tactical actions related to a previous game phase.

The Markov chain analysis showed that previous technical and tactical actions made from rucks had the highest probability of generating a transition phase leading to a CI.Winning teams may adopt a more flexible approach to the environmental changes that occur throughout a game.Higher variability in technical and tactical actions related to a previous game phase was observed in winning teams.The game action leading to CI moments for winning teams involved forwards and backs, while losing teams mainly depended on the involvement of forwards and eventually on opponent errors.Markov chain analysis may be a useful and valid tool to rugby match-play analysis considering the complex system framework.

The Relative Age Effect in Male and Female Brazilian Elite Volleyball Athletes of Varied Competitive Levels.

Volleyball is a popular sport in Brazil, and the relative age effect (RAE) is known to occur within it; but less is known of how RAE relates to elite Brazilian volleyball players' age, sex, and competitive levels. We aimed to investigate RAE prevalence with data from two seasons of play among players in the Superliga A (2020/2021 and 2021/2022 seasons), and Superliga B (2021 and 2022 seasons) made available from the Brazilian Volleyball Confederation (CBV), the club's official website, or direct consultation with the CBV. After removing duplicate data, we grouped these 1,063 athletes by their dates of birth, sex, and competition level (Superliga A or B). We divided players' birth dates into quarters (Q1: January-March, Q2: April-June, Q3: July-September and Q4: October-December) and into semesters, and we performed chi-square (χ2) tests to investigate RAE prevalence according to the players' sex and competitive level. RAE was prevalent overall (χ2 = 33.198; p < .001), among males (χ2 = 24.48; p < .001) and females (χ2 = 11.23; p < .011). Regarding competition level, RAE was evident among males in both Superliga A (χ2 = 14.581; p = 0.002), and B (χ2 = 13.985; p = 0.003), and among females in Superliga B (χ2 = 9.204; p = 0.027), but not Superliga A (χ2 = 4.012; p = 0.26). Thus, the RAE phenomenon operated differently for male and female Brazilian volleyball players according to their competitive level. We discuss the implications of these findings.

Effects of the learning tasks and the leadership profile of the coach on the perception of decision-making in young.

The objective of the research was to investigate the effects of the learning tasks and leadership profile of the coach on the subjective perception of decision-making. In total, 910 Brazilian adolescents (14.00 ± 1.8 years) and 57 Brazilian coaches (45.57 ± 7.25 years) were included in the study, participants of a sports program in 37 public schools in the city of Curitiba in the state of Paraná. Ordinal logistic regression was used to verify the independent associations between the variables and the tertiles of the scores for each decision-making characteristic. The small-sized game learning tasks were positively associated with commitment to decision-making learning (CR = 1.21, 95% CI = 1.01-1.49). Positive associations were also found between the coaches' leadership profile and decision-making competence.