Analysis Of Soccer Players' Positional Variability During The 2012 Uefa European Championship: A Case Study

The purpose of this study was to analyse players' positional variability during the 2012 UEFA European Championship by applying principal component analysis (PCA) to data gathered from heat maps posted on the UEFA website. We analysed the teams that reached the finals and semi-finals of the competition. The players' 2D coordinates from each match were obtained by applying an image-processing algorithm to the heat maps. With all the players' 2D coordinates for each match, we applied PCA to identify the directions of greatest variability. Then, two orthogonal segments were centred on each player's mean position for all matches. The segments' directions were driven by the eigenvectors of the PCA, and the length of each segment was defined as one standard deviation around the mean. Finally, an ellipse was circumscribed around both segments. To represent player variability, segment lengths and elliptical areas were analysed. The results demonstrate that Portugal exhibited the lowest variability, followed by Germany, Spain and Italy. Additionally, a graphical representation of every player's ellipse provided insight into the teams' organisational features throughout the competition. The presented study provides important information regarding soccer teams' tactical strategy in high-level championships that allows coaches to better control team organisation on the pitch.47122523

Identification, Computational Examination, Critical Assessment and Future Considerations of Spatial Tactical Variables to Assess the Use of Space in Team Sports by Positional Data: a Systematic Review

The aim of the review was to identify the spatial tactical variables used to assess the use of space in team sports using positional data. In addition, we examined computational methods, performed a critical assessment and suggested future considerations. We considered four electronic databases. A total of 3973 documents were initially retrieved and only 15 articles suggested original spatial variables or different computation methods. Spatial team sport tactical variables can be classified into 3 principal types: occupied space, total field coverage by several players; exploration space, the mean location (+/- standard deviations in X- and Y-directions) of the player/team during the entire game; and dominant/influence space, the region the players can reach before any other players. Most of the studies, i.e., 55%, did not include goalkeepers (GKs) and total playing space to assess occupied space, however, several proposed new variables that considered that all playing space could be "played" (i.e. effective free-space, normalized surface area). Only a collective exploration space variable has been suggested: the major range of the geometrical centre (GC). This suggestion could be applied to assess collective exploration space variables at a sub-system level. The measurement of the dominant/influence space has been based on the Voronoi region (i.e. distance d criteria), but several studies also based their computation on the time (t). In addition, several weighted dominant areas have been suggested. In conclusion, the use of spatial collective tactical variables considering the principal structural traits of each team sport (e.g. players of both teams, the location of the space with respect to the goal, and the total playing space) is recommende

Identification, Computational Examination, Critical Assessment and Future Considerations of Distance Variables to Assess Collective Tactical Behaviour in Team Invasion Sports by Positional Data: A Systematic Review

The aim of the study was the identification, computational examination, critical assessment and future considerations of distance variables to assess collective tactical behaviour in team invasion sports by positional data. A total of 3973 documents were initially retrieved. Finally, 72 articles met the inclusion criteria, but only 26 suggested original tactical variables based on the distance variables. The distance variables can be classified into player–player, player–space, player–ball, and Geometrical Centre (GC)–GC /player/space/goal. In addition, several nonlinear techniques have been used to analyse the synchronisation and predictability of the distance variables in team invasion sports. Player–opponent distance is of special interest in those sports in which man-marking is commonly used, and in the micro-structure close to scoring situations in all sports. In addition, player–player distances are used to measure the length and the width of the team and player–GC distance to assess the dispersion of the team. Player–space distances have been measured to assess the distance of the player/team-line to relevant areas of the playing space. Several techniques have been applied to analyse the synchronisation (i.e., Hilbert transformation and cluster analyses) and the complexity and regularity or predictability (i.e., approximate entropies, sample entropy, cross-sample entropy and average mutual information) of the distance variables in team invasion sports, revealing the lack of consensus. Although the distance variables may be interesting tactical variables when considered in isolation, it would be enriching to analyse the relationship among these variables

ANALYSIS OF THE SHOTS TO GOAL STRATEGIES OF FIRST DIVISION BRAZILIAN PROFESSIONAL SOCCER TEAMS

The purpose of this study was to analyze the shots to goal strategies during four soccer matches, through computational tracking. Software Dvideow was used to obtain data about players’ position and their technical actions and data treatment was performed in Matlab® environment. The results showed that the teams usually win the ball possession in their defensive soccer field and ball possessions that resulted in shot to goal can involve few or great number of passes depending on the game situation. Results do not corroborate with literature studies due to different methods of data treatment. Information about to these shots to goal strategies can help coaches to improve technical training, to find possible team mistakes and present it to players

COVERED DISTANCES ANALYSIS OF BRASILIAN PROFESSIONAL SOCCER PLAYERS OBTAINED BY AN AUTOMATIC TRACKING METHOD

The aim of this study is to present and analyse the covered distances of soccer players obtained automatic and simultaneously. Four matches of eight different teams of the Brazilian 1st Division Soccer Championship were filmed. Applying a previously developed automatic tracking method, the results of 55 outline players who participated in the whole game (n=55 players) are presented. The results of mean covered distance and standard deviations after 90 minutes are 10,012 ± 1,024 m. The mean covered distance in the 1st half was 5,173 m (± 394 m) highly significantly longer (

ANÁLISE QUANTITATIVA DA DISTRIBUIÇÃO EM QUADRA DE JOGADORES INICIANTES DE FUTSAL COM E SEM A POSSE DA BOLA

In futsal, the way players occupy space is considered one of the indicators of the quality of their playing level. This article aimed to analyze the distribution of players on the field, both with and without ball possession. A digital camera and a tracking system were used to monitor eight outfield players in the under-7 category, with an average age of 7.14 years, during two 10-minute periods. Values related to the covered area with and without ball possession were calculated. The results found that beginners consistently clustered in their spatial positioning throughout the game. It was concluded that the participants displayed a low level of play in terms of how they occupy space, making this an indicator deserving the attention of coaches in the teaching and learning process.En el fútbol sala, la forma en que los jugadores ocupan el espacio se considera uno de los indicadores de la calidad de su nivel de juego. Este artículo tuvo como objetivo analizar la distribución de los jugadores en la cancha, tanto con cómo sin posesión del balón. Se utilizó una cámara digital y un sistema de seguimiento para monitorear a ocho jugadores de campo en la categoría sub-7, con una edad promedio de 7,14 años, durante dos períodos de 10 minutos. Se calcularon los valores relacionados con el área de ocupación del equipo con y sin posesión del balón. Los resultados mostraron que los principiantes tienden a ocupar espacios de manera agrupada en todo momento del juego. Se concluyó que los participantes mostraron un bajo nivel de juego en cuanto a cómo ocupan el espacio, lo que convierte a este indicador en algo que merece la atención de los entrenadores en el proceso de enseñanza y aprendizaje.  No futsal, o modo como os jogadores ocupam o espaço é considerado um dos indicadores da qualidade do seu nível de jogo. O presente artigo teve como objetivo analisar a distribuição de jogadores iniciantes em quadra com e sem a posse da bola. Foram utilizados uma câmera digital e um sistema para o rastreamento de oito jogadores de linha da categoria sub-7, com média de 7,14 anos, durante dois períodos de 10 minutos. Os valores referentes à área de ocupação das equipes com e sem a posse da bola foram calculados. Os resultados encontrados mostram que em todos os instantes do jogo os iniciantes ocupam os espaços de maneira aglutinada. Concluiu-se que os participantes apresentaram um fraco nível de jogo referente ao modo como ocupam o espaço, sendo este um indicador que merece a atenção de treinadores no processo de ensino-aprendizagem.

Evaluation of the propulsion technique and motor performance of wheelchair basketball players

The objective of this study was to evaluate the propulsion technique of wheelchairs basketball athletes. The group of study was formed for 11 athletes practicing, the modality studied, with an average age of 30.27 ± 6.51 years. The sample was divided in two groups (faster, slowest) according to the performance in the agility and speed tests. To analyze the angular kinematics of the upper limbs, each person performed threeattempts to “round trip” in a distance of 5 meters. The results indicate a strong positive association between the results obtained in the speed and agility tests (r = 0.83; p = 0.002) and negative between speed test time and sports practice time (r = −0.68; p = 0.02). For the analysis of angular behavior significant difference was observed (p = 0.02), only in the variable maximum angle of the left elbow and the faster group presentedthe highest values. The angular behavior analyzes during all the movement, present significant difference at some point of the cycle, for the variables abduction angle on the left shoulder, absolute angle of the right and left forearm, absolute angles of the shoulder in the sagittal plane left and right, maximum angle of the right and left elbow. The results indicate that the athletes present specific characteristics of propulsion, andthat some angular movement characteristics, as a smaller angle of shoulder abduction during early stages of the propulsion, influence the performance in the speed test

Preliminary results on organization on the court, physical and technical performance of Brazilian professional futsal players: comparison between friendly pre-season and official match

The main aim of this study was to verify possible differences between a friendly pre-season match (FM) and an official in-season match (OM) regarding physical, technical, and organizational performances of a professional Brazilian futsal team. Ten professional futsal athletes participated in this study. The matches were monitored with video cameras (30 Hz) and athlete trajectories obtained with automatic tracking. The values obtained for distance covered per minute, percentage of distance covered at moderate intensity, team coverage area, spread, passes, possessions, ball touches and successful passes per minute were greater for the OM than FM. On the contrary, percentage of distance covered, standing and walking was greater for the FM than OM. We concluded that physical, technical, and tactical performances are different between a FM and an OM in futsal and also these parameters mutually influenced each other distinctly. Future studies should verify whether pre-season tournaments reproduce similar demands to a regular season official match

Agreement and correlation among three different methods for the quantification of the vertical jump height

O presente estudo teve como objetivo analisar a correlação e concordância entre três diferentes métodos para quantificação da altura do salto vertical: cinta de Abalakov (AB), tapete de contato (TC) e videogrametria (VG). Treze atletas de vôlei do sexo feminino. Realizaram três saltos verticais máximos com contramovimento sem o auxílio dos membros superiores. Os três métodos mediram a altura do salto simultaneamente. Foram realizados os testes de correlação de Pearson (r) entre cada par de métodos (AB x TC, AB x VG e TC x VG). Por fim, a concordância entre cada par de métodos foi avaliada através da análise gráfica de Bland e Altman. A menor correlação encontrada (r = 0,77; p < 0,01) ocorreu entre os métodos de VG e AB, enquanto que a maior correlação encontrada (r = 0,92; p < 0,01) ocorreu entre os métodos de VG e TC. Não houve concordância satisfatória entre os valores encontrados para os diferentes métodos, sugerindo que profissionais da área tenham cautela na comparação entre resultados de altura do salto vertical obtidos por diferentes métodos.The purpose of the present study was to analyze the association and the agreement among three different methods to quantify of the vertical jump height: abalakov belt (AB), contact mat (TC) and videogrammetry (VG). Thirteen female volleyball players performed three maximal countermovement jumps, without the help of upper limbs. The three methods were used simultaneously to quantify the jump height. The lowest correlation (r = 0.77; p < 0.01) was found between VG and AB, while the strongest correlation (r = 0.92; p < 0.01) was found between VG and TC methods. In addition, Bland and Altman plots revealed no satisfactory agreement between the methods. These findings suggest precaution to compare the results of vertical jump height from different methods

Evaluación isocinética de los músculos de la rodilla en jugadores de fútbol : análisis discriminante

Introdução: a atividade muscular em jogadores de futebol pode ser medida por meio do dinamômetro isocinético, que é um instrumento confiável para avaliação do desempenho humano. Objetivos: conduzir análises isocinéticas e discriminar quais variáveis diferenciam a categoria sub-17 (S17) da profissional (PRO).Métodos:Trinta e quatro jogadores de futebol (n=17 para cada categoria) foram avaliados. As variáveis isocinéticas utilizadas para a análise de extensão-flexão do joelho foram: pico de torque (Nm), trabalho total (J), potência média (W), ângulo de pico de torque (graus), razão agonista/antagonista (%), testadas em três velocidades (60°/s, 120°/s e 300°/s), com cada série contendo cinco repetições. Três análises discriminantes foram feitas usando o método Wilk's Lambda para identificar quais variáveis fariam uma discriminação significativa entre as duas categorias. Resultados: as variáveis discriminantes a 60°/s na categoria PRO foram: pico de torque extensores, trabalho total flexores, potência média de extensores e razão agonista/antagonista; e para os S17 foram: trabalho total de extensores, pico de torque de flexores e potência média de flexores. A 120°/s para a categoria PRO as variáveis discriminantes foram: pico de torque de flexores e potência média de extensores; para os S17 foram: trabalho total de extensores e potência média de flexores. A 300°/s, as variáveis encontradas para as categorias PRO e S17 foram, respectivamente: potência média de extensores e trabalho total de extensores. Conclusão: as variáveis isocinéticas para os músculos do joelho flexores e extensores foram capazes de fazer uma discriminação significativa entre jogadores de futebol PRO e S17.Introduction: muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: to perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: the discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players.Introducción: la actividad muscular en jugadores de fútbol puede ser medida por medio del dinamómetro isocinético, que es un instrumento confiable para evaluación del desempeño humano. Objetivos: conducir análisis isocinéticos y discriminar qué variables diferencian la categoría sub-17 (S17) de la profesional (PRO). Métodos: fueron evaluados treinta y cuatro jugadores de fútbol (n=17 para cada categoría). Las variables isocinéticas utilizadas para el análisis de extensión-flexión de la rodilla fueron: pico de torque (Nm), trabajo total (J), potencia media (W), ángulo de pico de torque (grados), razón agonista/antagonista (%), probadas en tres velocidades (60°/s, 120°/s y 300°/s), con cada serie conteniendo cinco repeticiones. Fueron realizados tres análisis discriminantes usando el método Wilk's Lambda para identificar qué variables harían una discriminación significativa entre las dos categorías. Resultados: las variables discriminantes a 60°/s en la categoría PRO fueron: pico de torque extensores, trabajo total flexores, potencia media de extensores y razón agonista/antagonista; y para los S17 fueron: trabajo total de extensores, pico de torque de flexores y potencia media de flexores. A 120°/s para la categoría PRO las variables discriminantes fueron: pico de torque de flexores y potencia media de extensores; para los S17 fueron: trabajo total de extensores y potencia media de flexores. A 300°/s, las variables encontradas para las categorías PRO y S17 fueron, respectivamente: potencia media de extensores y trabajo total de extensores. Conclusión: las variables isocinéticas para los músculos de la rodilla flexores y extensores fueron capaces de hacer una discriminación significativa entre jugadores de fútbol PRO y S17