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.

Effects of congested fixture and matches' participation on internal and external workload indices in professional soccer players.

This study aimed to verify the effects of congested fixture and matches' participation on internal and external workload indexes in professional Brazilian soccer players. Rate of perceived exertion-based training load (sRPE), distance- and accelerometry-based measures were daily monitored over 119 training sessions and 33 matches performed by 29 male outfield players. Weeks were classified as congested (n = 11, two or more matches within a 7-day period) and regular (n = 10, one match or less within a 7-day period). The players were divided based on the matches' participation: (1) players who played ≥ 60 min (G1); (2) players who played < 60 min (G2); (3) players who did not participate of the match (G3). The findings showed that independent of the levels of participation during the matches, regular weeks presented greater acute, monotony, and strain indices for internal and external workload measures than congested weeks. The G1 presented the highest values for most of the workload indices in both regular and congested weeks, except for monotony indices (internal and external load) that G2 showed greater values than G1 and G3. Coaches and practitioners should plan the training "doses" to reduce disparities of these different match's participation and congested schedule weeks.

Match running performance in Brazilian professional soccer players: comparisons between successful and unsuccessful teams.

BACKGROUND: This study aimed to compare the match running performance between bottom- and top-ranked teams in professional soccer players over the 2020 season of the Brazilian National 2nd Division League. In addition, this study verified the independent and interactive effects of playing position and contextual factors on running outputs between these teams. METHODS: Forty-eight professional male outfield soccer players participated in this study (top-ranked team, n = 24; bottom-ranked team, n = 24). The distance- and accelerometry-based measures were recorded during 69 matches using a global positioning system (10 Hz) integrated with an accelerometer (400 Hz). RESULTS: The top-ranked team covered greater total distance [median (interquartile range); 10,330.0 m (1430.0)] and high-acceleration [97.0 m (32.0)] than the bottom-ranked team, in home and away matches [p < 0.05, effect size (ES) = small]. The midfielders of the top-ranked team covered higher total distance, high-speed running (> 18 km h-1), high acceleration (≥ 3 m s-2), high-deceleration (≤ -3 m s-2), and performed more sprints [(> 25 km h-1) compared to midfielders of the bottom-ranked team (p < 0.05, η2 = small-moderate]. The matches against top-level opponents required high values of high-acceleration and number of sprints only for the top-ranked team (p < 0.05, ES = small). Independent analysis showed that match outcome (loss vs. draw vs. win) was not influenced by running performance for both bottom- and top-ranked teams (p > 0.05; η2 = small). However, the top-ranked team covered greater total distance, high-acceleration/deceleration than bottom-ranked team in loss matches (p < 0.05, η2 = small). CONCLUSIONS: These findings should be considered when the coaches and practitioners interpret the match running outputs and when evaluating the effects of training intervention on these performance indicators.

Correlation between skin temperature in the lower limbs and biochemical marker, performance data, and clinical recovery scales.

The aim of this study was to evaluate the correlation between tools commonly used in the detection of physiological changes, such as clinical complaints, a biochemical marker of muscle injury, and performance data during official matches, with infrared thermography, which has been commonly used in the possible tracking of musculoskeletal injuries in athletes. Twenty-two athletes from a professional soccer club (age 27.7 ± 3.93 years; BMI 24.35 ± 1.80 kg/cm2) were followed during the season of a national championship, totaling 19 matches with an interval of 7 days between matches. At each match, the athletes used a Global Positioning System (GPS) device to collect performance data. Forty-eight hours after each match, every athlete's perception of recovery, fatigue, and pain was documented. Blood was collected for creatine kinase (CK) analysis, and infrared thermography was applied. Only athletes who presented pain above 4 in either limb were included for thermographic analysis. Each thermographic image was divided into 14 regions of interest. For statistical analysis, we included only the images that showed differences ≥ 1° C. Data normality was verified by the Kolmogorov-Smirnov test with Dallal-Wilkinson-Lilliefors correction. We used the Pearson correlation coefficient to verify the correlation between infrared thermography and the biochemical marker, performance data, and clinical recovery scales. No correlation was observed between mean skin temperature and blood CK levels, pain level, perception of recovery, and fatigue perception (r <0.2, p>0.05). Thus, infrared thermography did not correlate with CK level, pain, fatigue perception, or recovery, nor with performance variables within the field.

Effects of Match-Related Contextual Factors on Weekly Load Responses in Professional Brazilian Soccer Players.

This study aimed to quantify the weekly training load distributions according to match location, opponent standard, and match outcome in professional soccer players. Rate-of-perceived-exertion-based training load (sRPE) and distance- and accelerometry-based measures were monitored daily during 52 training sessions and 11 matches performed by 23 players. Athletes who played ≥ 60 min during non-congested weeks were considered for data analysis. The training days close to away matches (e.g., one day before the match = MD-1) presented greater sRPE, distance-based volume measures, and mechanical work (player load) compared to the training days close to home matches (p = 0.001-0.002; effect size (ES) = medium-large). The most distant days of the home matches (e.g., five days before the match = MD-5) presented higher internal and external loads than before away matches (p = 0.002-0.003, ES = medium). Higher sRPE, distance-based volume measures, and mechanical work were found during the middle of the week (e.g., three days before the match, MD-3) before playing against bottom vs. medium-ranking teams (p = 0.001-0.01, ES = small-medium). These metrics were lower in MD-5 before matches against bottom vs. medium-ranking opponents (p = 0.001, ES = medium). Higher values of all external load measures were observed during the training session before winning matches (MD-1) compared to a draw or loss (p < 0.001-0.001, ES = medium-large). In conclusion, the training load distribution throughout the week varied considerably according to match-contextual factors.

Validity and reliability of a 6-a-side small-sided game as an indicator of match-related physical performance in elite youth Brazilian soccer players.

The aims of this study were: (i) to compare the external and internal load during a 6-a-side small-sided game (6v6-SSG) according to age-group; (ii) to relate these parameters between the 6v6-SSG and official matches; and (iii) to test the reliability of the 6v6-SSG. A total of 51 Brazilian youth soccer players participated in this study (U11 [n = 16]; U13 [n = 10]; U15 [n = 9]; U17 [n = 8]; U20 [n = 8]). Three experiments were conducted. Experiment A: fifty-one U11 to U20 players were submitted to 6v6-SSGs (n = 10 games; two for each age-group). Experiment B: thirty-two players were randomized to also play official matches (n = 6 matches). Experiment C: thirty-five youth players played the 6v6-SSG twice for test and retest reliability analysis. External load was obtained using Global Positioning Systems and the internal load parameter was calculated through mean heart rate. Statistical approaches showed progressive increases in all parameters according to categories (U11< U13< U15< U17< U20; p < 0.05; ES = 0.42-23.68). Even controlling for chronological age, all parameters showed likely to almost certain correlations between 6v6-SSG and official matches (r = 0.25-0.92). Collectively, the proposed protocol indicates good reliability (CV% = 2.0-12.6; TE% = 2.3-2.7%; ICC = 0.78-0.90). This research suggests that the 6v6-SSG is an alternative tool to indicate match-related physical performance in youth soccer players.

Effects of 22 weeks of training on functional markers and match performance of young soccer players

The aim of this study was to verify the effects of 22 weeks of training on functional markers and match performance through the use of earned points in competition. Twenty male soccer players were submitted to the same group of tests in four moments of the periodization: before the preparatory stage (T0); after the preparatory stage (T1); after the competitive stage I (T2); after the competitive stage II (T3). The functional markers were measured using the vertical and horizontal jump, T-40; Shuttle Run Test and RAST. The match performance was obtained by earned points in competition. An increase were found for all the variables analyzed for functional markers when T0 was compared with T3. In relation to the match performance, the team obtained 83.33% success in competitive stages. It is possible to conclude that training plan was efficient to improve technical-tactical skills and physical fitness of the studied athletes

Relationship between Procedural Tactical Knowledge and Specific Motor Skills in Young Soccer Players.

The purpose of this study was to investigate the association between offensive tactical knowledge and the soccer-specific motor skills performance. Fifteen participants were submitted to two evaluation tests, one to assess their technical and tactical analysis. The motor skills performance was measured through four tests of technical soccer skills: ball control, shooting, passing and dribbling. The tactical performance was based on a tactical assessment system called FUT-SAT (Analyses of Procedural Tactical Knowledge in Soccer). Afterwards, technical and tactical evaluation scores were ranked with and without the use of the cluster method. A positive, weak correlation was perceived in both analyses (rho = 0.39, not significant p = 0.14 (with cluster analysis); and rho = 0.35; not significant p = 0.20 (without cluster analysis)). We can conclude that there was a weak association between the technical and the offensive tactical knowledge. This shows the need to reflect on the use of such tests to assess technical skills in team sports since they do not take into account the variability and unpredictability of game actions and disregard the inherent needs to assess such skill performance in the game.

Long distance run induced hydration and kidney function changes in marathoners / Corrida de longa distância induz a mudanças no estado de hidratação e na função renal em maratonistas / Funcionamiento para un cambios de larga distancia inducido en el estado de hidratación y función renal en maratonistas

The aim of the study was to verify the hydration status and the kidney function in marathoners during the training season and after a marathon race. Nine male runners were investigated during 12 weeks of training. Urine was collected in four moments; in the beginning (C1) and during (C2) the training program, before (C3) and after (C4) the competition. Urine pH was measured using reagent tapes, urine density with a refractometer, protein excretion by Bradford assay and erythrocytes and leucocytes by microscopy. Changes were observed when C-4 was compared to the other collection times for all variables investigated. It is possible to conclude that physical exertion induced important changes in the hydration status and glomerular membrane selectivity to macromolecules, modifying the kidney function of the marathoners in C4.

O objetivo do estudo foi verificar o estado de hidratação e a função renal de maratonistas durante uma temporada preparatória e após a competição. Foram estudados nove maratonistas durante 12 semanas de treinamento. A urina foi coletada em quatro momentos: antes (C1) e durante (C2) o protocolo de treinamento, antes (C3) e após (C4) a competição. Foram mensurados o pH a partir de tiras de reagentes, a densidade por meio do refratômetro, a proteinúria pelo ensaio de Bradford, concentração de eritrócitos e de leucócitos por microscopia. Alterações foram encontradas quando comparado o C-4 com as coletas anteriores para todas as variáveis estudadas. Pode-se concluir que o exercício físico induziu a modificações importantes no estado de hidratação dos corredores e na função da membrana glomerular, modificando assim, a função renal dos maratonistas no momento pós prova.

El objetivo del estudio fue determinar el estado de hidratación y la función renal en los corredores de maratón durante una temporada de preparación y después de la competición. Se estudiaron nueve corredores durante 12 semanas de entrenamiento. La orina se recogió en cuatro momentos: antes y durante el protocolo de entrenamiento, antes y después de la competición. PH de tiras reactivas, de densidad a través del refractómetro, proteinuria por Bradford ensayo, concentración de eritrocitos y leucocitos fueron medidos por microscopía. No se encontraron cambios al comparar el C-4 con las colecciones anteriores para todas las variables. Se puede concluir que el ejercicio induce cambios significativos en el estado de hidratación de los corredores y la función de la membrana glomerular, modificando de este modo la función renal del tiempo de maratón después de la carrera.

Rothia aeria endocarditis in a patient with a bicuspid aortic valve: case report

Rothia aeria is an uncommon pathogen mainly associated with endocarditis in case reports. In previous reports, endocarditis by R. aeria was complicated by central nervous system embolization. In the case we report herein, endocarditis by R. aeria was diagnosed after acute self-limited diarrhea. In addition to the common translocation of R. aeria from the oral cavity, we hypothesize the possibility of intestinal translocation. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and genetic sequencing are important tools that can contribute to early and more accurate etiologic diagnosis of severe infections caused by Gram-positive rods.

Rothia aeria endocarditis in a patient with a bicuspid aortic valve: case report.

Rothia aeria is an uncommon pathogen mainly associated with endocarditis in case reports. In previous reports, endocarditis by R. aeria was complicated by central nervous system embolization. In the case we report herein, endocarditis by R. aeria was diagnosed after acute self-limited diarrhea. In addition to the common translocation of R. aeria from the oral cavity, we hypothesize the possibility of intestinal translocation. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and genetic sequencing are important tools that can contribute to early and more accurate etiologic diagnosis of severe infections caused by Gram-positive rods.