Biological maturation influences selection process in youth elite soccer players.

This study examined the influence of birth date, salivary testosterone [sT] concentration, sexual maturity status, and general strength on the selection process of an elite Brazilian soccer club during a 12-month period, which was a 2nd phase of a 24-month selection process. The stature, body mass, sT, sexual maturity status [Tanner scale], and hand grip strength were assessed for 143 players during 2 weeks. From these 143 players, 100 players were dismissed [DIS] and 43 players were selected to integrate the club's under-14 squad. Following 1-year training period, the under-14 team was assembled with 9 players designated as starters [STA], and then, comparisons were conducted taking into account a group of non-starters (selected; SEL = 34 players) and STA (n = 09). The DIS, SEL, STA players, and reference population, were compared for birth distribution. A greater proportion of players was born in the first trimester in the STA [75.0%], SEL [57.1%] and DIS [50.0%] groups compared to the reference population [25.8%]. One-way ANOVA showed a higher sT for STA group [516.0 ± 129.9 pmol·L-1], compared to SEL [415.5 ± 117.9 pmol·L-1] and DIS groups [390.9 ± 84.9 pmol·L-1; p = 0.003), and Kruskall-Wallis test showed a higher gonadal development for STA compared to DIS [p = 0.001]. The current findings suggest a strong influence of birth date and biological maturation on young soccer players selection process. Soccer coaches should consider these influences when making decisions about player selection of elite youth players.

Training intensity distribution of young elite soccer players / Distribuição da intensidade de treinamento em jovens jogadores de futebol

Abstract The current study described the training load and intensity distribution of 30 elite Under 20 soccer players (17.9 ± 0.6 years, 180.3 ± 5.7 cm, 73.7 ± 8.8kg) from a 3-time FIFA Club World Cup champion. Session-rating of perceived exertion (s-RPE), internal training load (ITL) and monotony were recorded across 40 training sessions. Mixed-effects modeling was used for data analysis. The athletes performed 33.0 ± 6.9 out of 40 planned training sessions. Most common reasons for absence from training included sickness or minor injuries. Overall, these training sessions summed 2928.7 ± 627.6 minutes. Athletes performed significantly more training sessions at low and moderate intensity zones than at high-intensity zone (p <0.0001). The current data indicate that elite young soccer players perform their training sessions predominantly at the low-intensity zone. Training monitoring is an important aspect of the sport training process evolution. In fact, previous evidence has already shown that an appropriate intensity distribution prevents maladaptation from sports training and may optimize athletic performance. Therefore, coaches should implement strategies to monitor training loads during pre-season and competitive periods.

Resumo O presente estudo descreveu a carga de treinamento e a distribuição de intensidade de 30 jogadores de elite de futebol sub 20 (17,9 ± 0,6 anos, 180,3 ± 5,7 cm, 73,7 ± 8,8 kg) de um clube de elite do estado de São Paulo. Durante 40 sessões de treinamento, a percepção subjetiva de esforço, bem como a carga interna de treinamento e a monotonia foram registradas. Os dados foram analisados por modelagem linear mista. Os atletas realizaram 33,0 ± 6,9 das 40 sessões de treinamento planejadas. As razões mais comuns para a ausência nas sessões de treinamento incluíram doenças ou lesões leves. De forma geral, essas sessões somaram 2928,7 ± 627,6 minutos. Os atletas realizaram significativamente mais sessões de treinamento em zonas de baixa e moderada intensidade comparado com a zona de alta intensidade (p <0,0001). Os dados do presente estudo indicam que os jovens jogadores de elite realizam suas sessões de treinamento predominantemente na zona de baixa intensidade. O monitoramento do treinamento colabora para a evolução do processo de treinamento esportivo. De fato, evidências anteriores já mostraram que a distribuição de intensidade apropriada impede a mal adaptação ao treinamento esportivo e pode otimizar o desempenho atlético. Portanto, treinadores devem implementar estratégias para monitorar as cargas de treinamento durante os períodos de pré-temporada e de competição.

The influence of genetic polymorphisms on performance and cardiac and hemodynamic parameters among Brazilian soccer players.

This study investigated whether ACTN3 R577X, AMPD1 C34T, I/D ACE, and M235T AGT polymorphisms can affect performance tests such as jumping, sprinting, and endurance in 220 young male athletes from professional minor league soccer team from São Paulo Futebol Clube, Brazil. I/D ACE and M235T AGT polymorphisms were also analyzed according to cardiac and hemodynamic parameters. Athletes were grouped or not by age. DNA from saliva and Taqman assays were used for genotyping 220 athletes and the results were associated with performance tests. Ventricle mass, ventricle end-diastolic diameter, end-diastolic volume, and ejection fraction were assessed by echocardiogram. Arterial pressure, heart rate, and oximetry were assessed by a cardioscope. The main results of this study were that athletes who carried RR/RX (ACTN3) and DD (ACE) genotypes presented better performance during jump and sprint tests. On the other hand, athletes with ID/II genotype presented better results during endurance test, while AGT genotypes did not seem to favor the athletes during the evaluated physical tests. CC genotype (AMPD1) only favored the athletes during 10-m sprint test. Although there are environmental interactions influencing performance, the present results suggest that RR/RX ACTN3 and ACE DD genotypes may benefit athletes in activities that require strength and speed, while II ACE genotype may benefit athletes in endurance activities. This information could help coaches to plan the training session to improve the athletes' performance.

Is the technical performance of young soccer players influenced by hormonal status, sexual maturity, anthropometric profile, and physical performance?

The aim of this study was to examine the influence of hormonal status, anthropometric profile, sexual maturity level, and physical performance on the technical abilities of 40 young male soccer players during small-sided games (SSGs). Anthropometric profiling, saliva sampling, sexual maturity assessment (Tanner scale), and physical performance tests (Yo-Yo and vertical jumps) were conducted two weeks prior to the SSGs. Salivary testosterone was determined by the enzyme-linked immunosorbent assay method. Technical performance was determined by the frequency of actions during SSGs. Principal component analyses identified four technical actions of importance: total number of passes, effectiveness, goal attempts, and total tackles. A multivariate canonical correlation analysis was then employed to verify the prediction of a multiple dependent variables set (composed of four technical actions) from an independent set of variables, composed of testosterone concentration, stage of pubic hair and genitalia development, vertical jumps and Yo-Yo performance. A moderate-to-large relationship between the technical performance set and the independent set was observed. The canonical correlation was 0.75 with a canonical R2 of 0.45. The highest structure coefficient in the technical performance set was observed for tackles (0.77), while testosterone presented the highest structure coefficient (0.75) for the variables of the independent set. The current data suggest that the selected independent set of variables might be useful in predicting SSG performance in young soccer players. Coaches should be aware that physical development plays a key role in technical performance to avoid decision-making mistakes during the selection of young players.

The effects of ball possession status on physical and technical indicators during the 2014 FIFA World Cup Finals.

This study examined the effect of high- (HPBPT) and low-percentage ball possession (LPBPT) on physical and technical indicators during 2014 FIFA World Cup matches. This would enable a regression model to be constructed to further understand the impact of different ball possession (BP) strategies on match performance. Data were collected from 346 international soccer players using a multiple-camera computerised tracking system. Although players in HPBPT covered lower distances (P < 0.01) in total and at low speed compared to LPBPT, this produced a trivial effect size (ES). However, they covered similar distances (P > 0.05) at medium and high speeds. Players in LPBPT covered more distance without BP but less with BP than HPBPT (P < 0.01; ES large). All positions in LPBPT spent less time in the opposing half and attacking third than the players in HPBPT (P < 0.01; ES small-moderate), but all positions in HPBPT completed more short and medium passes than LPBPT (P < 0.01; ES moderate). Players in HPBPT produced more solo runs into the attacking third and penalty area than LPBPT (P < 0.05, ES small). The equation to predict BP from physical and technical indicators highlighted the importance of distances covered (total, with and without BP), time spent in the attacking third and successful short passes during matches. In practical terms, high or low BP does not influence the activity patterns of international matches although HPBPT spend more time in offensive areas of the pitch.

Efeito da preparação integrada sobre a aptidão aeróbia, a potência e a velocidade de jovens futebolistas / Effect of integrated training on aerobic fitness, muscular power and speed of young footballers

O objetivo deste estudo foi avaliar o efeito do modelo integrado de preparação física, adotada pela equipe campeã da Copa Independência Bicentenário em 2010, sobre a aptidão aeróbia, a potência e a velocidade de jovens atletas. Dezesseis jogadores de futebol (17,2±0,7 anos; 179,6±4,2 cm; massa corporal 74,6±5,8 kg) da categoria sub-17 foram submetidos a 11 semanas de preparação, incluindo a competição (11a semana), as quais incluíram sessões de treinamento técnico-tático, jogos reduzidos, treinamentos "coletivos", jogos amistosos e jogos oficiais. Foram realizados testes para a avaliação da aptidão aeróbia, potência de membros inferiores e velocidade. Foi observado incremento significante da potência aeróbia (p<0,05) do momento pré para o momento pós-treinamento. Nenhuma alteração significante foi detectada para a potência e a velocidade (p>0,05). Estes resultados sugerem que a estratégia de preparação física, com ênfase na integração entre o componente físico e o componente técnico-tático, promoveu incremento da aptidão aeróbia de jovens futebolistas; entretanto, o desenvolvimento da potência e velocidade não apresentou alteração.(AU)

The aim of this study was to evaluate the effect of integrated training strategy, adopted by the team who won the "2010 Independência Bicentenário Cup", on aerobic fitness, muscular power and speed of young players. Sixteen soccer players (age 17.2±0.7 years; 179.6±4.2 cm; body mass 74.6±5.8 kg; category under-17) underwent 11 weeks of preparation, including the competition (11th week). The training program included sessions for technical and tactical training, small-sided games, simulated training matches, friendly matches, and competitive matches. Assessments of aerobic fitness, lower limb power and speed were performed. A significant increase aerobic performance was observed after the training period (p<0.05). No significant change was detected for muscular power and speed (p>0.05). These results suggest that the training strategy adopted, with emphasis on integration between the physical component and the technical-tactical component, evoked a positive adaptation in aerobic fitness of young soccer players. However, the development of muscular power and speed seems to be compromised.(AU)

Desempenho tático de jogadores sub-15 do são paulo futebol clube a partir do teste fut-sat / Rendimiento táctico de jugadores sub 15 de sao paulo fútbol club utilizando el fut-sat / Tactical performance of u-15 players from sao paulo football club using fut-sat test

O presente estudo teve como objetivo analisar o desempenho tático de jogadores de futebol da categoria sub-15 pertencentes ao São Paulo Futebol Clube. Foram avaliadas 1787 ações táticas realizadas por 30 jogadores. Os dados foram coletados e analisados utilizando o teste FUT-SAT. As variáveis analisadas foram Número de Ações (NA), Percentual de Acerto (%A) e Índice de Performance Tática (IPT). Análises descritivas (média, desvio padrão) e o teste de normalidade Shapiro-Wilk, com um nível de significancia (p≤0,05), foram realizados através do software BioEstat 5.0 for Windows. Os resultados mostram que houve um maior NA na Fase Defensiva de jogo, porém os resultados da Fase Ofensiva alcançaram maiores %A e IPT. Concluiu-se que os jogadores avaliados apresentaram um jogo ofensivo mais eficiente e eficaz quando comparado ao defensivo...

Este estudio tuvo como objetivo analizar el rendimiento táctico de los jugadores de fútbol sub 15 pertenecientes al Sao Paulo Fútbol Club. Se evaluaron 1.787 acciones tácticas realizadas por 30 jugadores. Los datos fueron recogidos y analizados mediante el FUT-SAT. Las variables analizadas fueron: Número de Acciones, Porcentaje de Éxito e Índice de Desempeño Táctico (IDT). Los análisis descriptivos (media, desviación estándar) y la prueba de normalidad Shapiro-Wilk, con un nivel de significación (p≤0,05), fueron realizadas por el software BioEstat 5.0 para Windows. Los resultados muestran que hubo un número de acciones más alto en las acciones defensivas, pero los resultados obtenidos en la fase ofensiva eran superiores en Porcentaje de éxito y IDT. Se concluyó que los jugadores evaluados presentaron un juego ofensivo más eficiente y eficaz en comparación con lo juego defensivo...

The aim of study was to analyze the tactical performance of U-15 soccer players from Sao Paulo Football Club. Considering actions performed by 30 players, 1,787 tactical actions were evaluated. Data was collected and analyzed using FUT-SAT test. The variables analyzed were: Number of tactical actions, Success Percentage and Tactical Performance Index (TPI). A descriptive statistics (mean, standard deviation) and the Shapiro-Wilk normality test, with a significance level (p≤0.05), were performed by the BioEstat 5.0 for Windows software. The number of tactical actions during the defensive phase of the game was superior. However, the results of the offensive phase had higher values in success percentage and TPI. Finally, the results showed a number of tactical actions higher in defensive phase of the game, but the results of the offensive phase achieved higher success percentage and TPI. This indicated a better quality of offensive actions compared to defensive actions...

The relative age effect in soccer: a case study of the São Paulo Football Club / Efeito da idade relativa no Futebol: o estudo de caso do São Paulo Futebol Clube

The aim of this study was to compare the birth-date distribution of youth athletes of a high-level Brazilian soccer club with the general population of the same age group. In a cross-sectional study, the birth date of 341 youth athletes (under 10-20) was compared with a reference population (live births that occurred in São Paulo state in the same age group; n = 5,480,868). The subjects were divided into quarters of birth: 1st = January-March; 2nd = April-June; 3rd = July-September; 4th = October-December. The chi-square test (χ2) was used to compare the expected (reference population) and observed (athletes) distributions. It was detected a significant difference between the expected distribution and observed distribution (χ2= 29.53; p<0.0001), with a higher percentage of athletes born in the 1st quarter (47.5%) and a lower percentage in the 4th quarter (8.8%). The present results confirm the occurrence of the relative age effect (RAE) during the player selection process in a top-level Brazilian soccer club. The occurrence of this phenomenon during the selection and development of young athletes needs to be taken into account and should be analyzed carefully in order to minimize the loss of potential youth soccer talent. Further studies are required to identify the determinants of RAE and to establish preventive strategies that ensure a more efficient selection process of young soccer players.

O objetivo do presente estudo foi comparar a distribuição das datas de nascimento dos atletas das categorias de base de um clube da elite do futebol brasileiro com a população do estado de São Paulo da mesma faixa etária. Por meio de estudo transversal, as datas de nascimento de 341 atletas das categorias de base de um clube de São Paulo (sub 10-20) foram comparadas com uma população de referência (nascidos vivos do Estado de São Paulo da mesma faixa etária; n = 5.480.868). Os indivíduos foram distribuídos por trimestre de nascimento: 1° = Janeiro a Março; 2° = Abril a Junho; 3° = Julho a Setembro; 4° = Outubro a Dezembro. Para análise comparativa entre a distribuição esperada (população de referência) e a distribuição observada (atletas), foi utilizado o teste qui-quadrado (χ2). Foi detectada diferença significante entre a distribuição esperada e a distribuição observada (χ2= 29,53; p<0,0001), com maior concentração de atletas nascidos no 1° trimestre (47,5%) e menor no 4° trimestre (8,8%). Os resultados do presente estudo confirmam a existência do "efeito da idade relativa" (EIR) no processo de seleção de atletas em um clube de elite do futebol brasileiro. A ocorrência deste fenômeno durante o processo de seleção e formação de jovens atletas precisa ser considerada e analisada cuidadosamente, a fim de minimizar a exclusão de jovens atletas de futebol potencialmente talentosos. Estudos adicionais são necessários para identificar os fatores determinantes do EIR e promover estratégias preventivas que tornem o processo de seleção e formação de jovens futebolistas mais eficiente.

Efeito do modelo de periodização com cargas seletivas sobre capacidades motoras durante um mesociclo preparatório em jogadores de futsal / Effect of the periodization model with selective loads on motor abilities during a preparatory mesocycle in futsal players / Los efectos del modelo de la periodización con cargas selectivas en las habilidades motoras durante un mesociclo preparatorio en jugadores de futsal

O objetivo deste estudo foi verificar o efeito do modelo de cargas seletivas durante um mesociclo preparatório em jogadores de futsal profissionais. Nove jogadores de futsal (23±2 anos) de uma equipe da Federação Paulista de Futebol de Salão compuseram a amostra, caracterizada como intencional. Aptidão aeróbia intermitente, salto horizontal, salto triplo unipodal, velocidade de 15m, agilidade e potência anaeróbia foram avaliadas em dois momentos: microciclo-2 (PRE) e microciclo-7 (POS). A análise estatística compreendeu o teste-t de Student e teste Wilxocon (P<0,05). Salto horizontal, aptidão aeróbia intermitente e potência média melhoraram, a velocidade nos 15 m piorou. O modelo de cargas seletivas é uma boa opção de periodização para o mesociclo preparatório no futsal.

The aim of this study was to verify the effect of selective loads model in professional futsal players, during a preparatory mesocycle. Nine futsal professional players (23±2 anos), from the team of Federation Paulista of soccer indoor championship, composed the sample, characterized by intentional. The players were evaluated in two moments although of a preparatory mesocycle, microcycle 2 (PRE) and microcycle 7 (POS), by the tests of intermittent aerobic fitness, horizontal jump, one leg triple jump, velocity of 15m, agility and anaerobic power. The statistical analysis included the Student-t and Wilxocon tests (P<0.05). The results of horizontal jump, intermittent aerobic fitness and medium power improved, the velocity at 15 m decreased. The select loads model is a good option for the periodization to preparatory mesocycle in futsal.

El objetivo de este estudio fue determinar el efecto del modelo con cargas selectivas durante el mesociclo preparatorio en jugadores de futsal. Nueve jugadores de futsal (23±2 anos) que pertenecen a un equipo de campeonato Paulista de Fútbol de Salón, compuso la muestra, que se caracteriza como intencional. Aptitud aeróbica intermitente, salto horizontal, triple salto con uno de los pies, velocidad del 15m, agilidad y potencia anaerobica fueron evaluados en dos momentos: mesociclo-2 (PRE) y mesocilo-7 (POS). Análisis estadístico incluyó la prueba del t-Student y la prueba del Wilxocon (P<0,05 ). Salto horizontal, aptitud aerobic intermitente y potencia media han mejorado, la velocidad en los 15 m ha empeorado. El modelo con cargas selectivas es una buena opción para la periodización durante mesociclo preparatorio en el futsal.

Perfil antropométrico, aptidão motora e aeróbia de jogadores de futebol profissionais e juniores de Trinidad e Tobago / Anthropometric profile, motor and aerobic fitness of Trinidad and Tobago professional and juniors soccer players

Há pouca informação sobre equipes de futebol do Caribe. Dessa forma, o objetivo do estudo foi descrever o perfil antropométrico, aptidão motora e aeróbia entre jogadores de futebol profissionais e juniores de uma equipe de Trinidad e Tobago. Vinte e seis jogadores de futebol foram avaliados (14 profissionais e 12 juniores): antropometria (estatura, massa corporal, IMC, percentual de gordura), flexibilidade (sentar e alcançar), velocidade (30m), força explosiva (salto horizontal e vertical), potência anaeróbia (potência máxima, média, mínima e o índice de fadiga) e potência aeróbia máxima. O teste-t de Student para amostras indepentendes foi utilizado na análise estatística, considerando 5% de significância (p<0,05). Os resultados dos jogadores profissionais e juniores foram, respectivamente: estatura (180,6 ± 8,1; 175,0 ± 6,9 cm); massa corporal (77,1 ± 7,5; 70,6 ± 8,7 kg); IMC (23,6 ± 1,5; 23,0 ± 1,6 kgm2); gordura corporal (11,9 ± 1,7; 11,6 ± 1,2 %); sentar e alcançar (24,9 ± 10,3; 24,9 ± 7,7 cm); tempo nos 30 m. (4,61 ± 0,14 e 4,66 ± 0,15 s); salto horizontal (263,4 ± 14,9 e 239,7 ± 12,1 cm); salto vertical (58,7 ± 4,3; 54,6 ± 6,6 cm); potência máxima (7,9 ± 0,9; 6,6 ± 0,8 w∙kg-1); potência média (6,5 ± 0,7; 5,4 ± 0,9 w∙kg-1); potência mínima (5,3 ± 0,7; 4,3 ± 1,1 w∙kg-1); índice de fadiga (33,0 ± 7,9; 34,8 ± 12,8 %); potência aeróbia (55,0 ± 3,2; 57,2 ± 4,8 ml∙kg-1∙min-1). Os jogadores profissionais apresentaram salto horizontal e as potência anaeróbia máxima, média e mínima maiores do que os juniores. Os maiores valores nos testes de potência dos membros inferiores podem estar relacionados ao maior tempo de prática na modalidade dos jogadores profissionais, o que também pode indicar maior nível de especialização, o qual prioriza os treinamentos de potência (força e velocidade).

There is little information on Caribbean soccer players. Thus, the aim this study was to descriptive and to compare the anthropometric, motor and aerobic fitness profile between Trinidad and Tobago team professional and junior soccer players. Twenty six soccer players were evaluated (14 professional and 12 junior): anthropometric (height, body mass, BMI, body fat percent), flexibility (sit and reach), velocity (30 m), explosive strength (horizontal and vertical jump), anaerobic power (maximum, mean and minimum power, index of fatigue) and maximum aerobic power. Student Test-t to independent sample was used in statistical analyzes, considering 5% of significance (p<0,05). Results of professional and junior players were, respectively: height (180,6 ± 8,1; 175,0 ± 6,9 cm), body mass (77,1 ± 7,5; 70,6 ± 8,7 kg); BMI (23,6 ± 1,5 / 23,0 ± 1,6 kgm2); body fat (11,9 ± 1,7; 11,6 ± 1,2 %); sitting and reaching (24,9 ± 10,3; 24,9 ± 7,7 cm); velocity (30 m) (4,61 ± 0,14; 4,66 ± 0,15 s); horizontal jump (263,4 ± 14,9; 239,7 ± 12,1 cm); vertical jump (58,7 ± 4,3; 54,6 ± 6,6 cm); maximum power (7,9 ± 0,9; 6,6 ± 0,8 w∙kg-1); mean power (6,5 ± 0,7; 5,4 ± 0,9 w∙kg-1); minimum power (5,3 ± 0,7; 4,3 ± 1,1 w∙kg-1); index of fatigue (33,0 ± 7,9; 34,8 ± 12,8 %); aerobic power (55,0 ± 3,2; 57,2 ± 4,8 ml∙kg-1∙min-1). Professional players presented higher horizontal jump and maximum, mean and minimum anaerobic power in comparing to the junior players. The highest values of power tests for the lower limbs may be relationship to the longer time of practice in the modality of professional players, which can also indicate a higher level of specialization, which gives priority to the training of power (force and velocity).