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Martins, Fernando Manuel Lourenço

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Now showing 1 - 10 of 17
  • Team’s performance on FIFA U17 World Cup 2011 : study based on notational analysis
    Publication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, Rui
    The main objective of the notational analysis of the game includes optimizing feedback to the performer and coach to improve performance (Liebermann, Katz, Hughes, Bartlett, McClements & Franks, 2002). The main objective of this work was to analyze the profile of the teams that competed on FIFA U-17 World Cup at 2011, most exactly, trying understanding the offensive profile of the most successful teams. In this way we applied the test of correlation to verify if the goals for average are related to number of matches (i.e., more successful teams). There is statistical evidence to assert that the pairs (wins and goals) are positively moderating related (p = 0.001). In fact it appears that there is a directly intimacy between pairs (since the linear correlation coefficient r (24) = 0.774), i.e., how much more goals for average, more wins happens. Through the analysis of dependent variables is possible to say that teams who wins more games, have a superior mean of goals per match but, in the case of goals against, the teams that achieve the higher level in competition have higher mean of the goals against. However are the teams that play more matches that show higher level of goals for average.
  • Node and network entropy : a novel mathematical model for pattern analysis of team sports behavior
    Publication . M. L. Martins, Fernando; Gomes, Ricardo; Lopes, Vasco; G. M. Silva, Frutuoso; Mendes, Rui
    Pattern analysis is a well-established topic in team sports performance analysis, and is usually centered on the analysis of passing sequences. Taking a Bayesian approach to the study of these interactions, this work presents novel entropy mathematical models for Markov chain-based pattern analysis in team sports networks, with Relative Transition Entropy and Network Transition Entropy applied to both passing and reception patterns. To demonstrate their applicability, these mathematical models were used in a case study in football—the 2016/2017 Champions League Final, where both teams were analyzed. The results show that the winning team, Real Madrid, presented greater values for both individual and team transition entropies, which indicate that greater levels of unpredictability may bring teams closer to victory. In conclusion, these metrics may provide information to game analysts, allowing them to provide coaches with accurate and timely information about the key players of the game.
  • Using network metrics to investigate football team players’ connections : a pilot study
    Publication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, Rui
    The aim of this pilot study was propose a set of network methods to measure the specific properties of football teams. These metrics were organized on “meso” and “micro” analysis levels. Five official matches of the same team on the First Portuguese Football League were analyzed. An overall of 577 offensive plays were analyzed from the five matches. From the adjacency matrices developed per each offensive play it were computed the scaled connectivity, the clustering coefficient and the centroid significance and centroid conformity. Results showed that the highest values of scaled connectivity were found in lateral defenders and central and midfielder players and the lowest values were found in the striker and goalkeeper. The highest values of clustering coefficient were generally found in midfielders and forwards. In addition, the centroid results showed that lateral and central defenders tend to be the centroid players in the attacking process. In sum, this study showed that network metrics can be a powerful tool to help coaches to understanding the specific team’s properties, thus supporting decision-making and improving sports training based on match analysis.
  • A systemic overview of football game : the principles behind the game
    Publication . Manuel Clemente, Filipe; M. L. Martins, Fernando; Mendes, Rui; Figueiredo, António José
    The football game is a specific system constituted by many players’ interactions. The specific nature of such sport must be properly analyzed and discussed in sport community in order to understand the principles that rules the system organization. As a team sport with specific properties it is truly important to discuss how players’ interactions from the dynamic nature of game. Therefore, the aim of this study is to classify the football game as a team sport and to discuss their specific dynamic that determines the emergence of a tactical behavior and a strategic definition. Such discussion can be important to determine the specific pedagogical and didactical contents to teach at youth football training and even in Physical Education classes.
  • Social network analysis : mathematical models for understanding professional football in game critical moments : an exploratory study
    Publication . A, Diana; Pedrosa, Isabel; Mendes, Rui; M. L. Martins, Fernando; Francisco, João; Gomes, Ricardo; Dias, Gonçalo
    Considering the Social Network Analysis approach and based on the creation of mathematical models, the aim of this study is to analyze the players’ interactions of professional football teams in critical moments of the game. The sample consists in the analysis of a 2019/2020 season UEFA Champions League match. The mathematical models adopted in the analysis of the players (micro analysis) and the game (macro analysis) were obtained through the uPATO software. The results of the networks indicated a performance pattern trend more robust in terms of the mathematical model: Network Density. As far as it concerned, we found that the Centroid Players had a decisive role in the level of connectivity and interaction of the team. Regarding the main critical moments of the game, the results showed that these were preceded by periods of great instability, obtaining a differentiated performance in the following mathematical models: Centrality, Degree Centrality, Closeness Centrality, and Degree Prestige. We concluded that the networks approach, in concomitance with the dynamic properties of mathematical models, and the critical moments of the game, can help coaches to better evaluate the level of interaction and connectivity of their players toward the actions imposed by opponents.
  • The social network analysis of Switzerland football team on FIFA World Cup 2014
    Publication . Manuel Clemente, Filipe; M. L. Martins, Fernando; Kalamaras, Dimitris; Oliveira, Joana; Oliveira, Patrícia; Mendes, Rui
    The aim of this study was to apply the social network analysis approach to the football match analysis case. For such, it was analyzed the Switzerland national football team during the FIFA World Cup 2014 tournament. Two general network metrics (total links and network density) and two centrality metrics (degree centrality and degree prestige) were computed. Four matches from Switzerland in FIFA World Cup 2014 were analysed in this study. A total of 334 adjacency matrices corresponding to 334 units of attack were generated based on the teammates’ interactions and then converted in 4 network graphs. A total of 1129 passes were analysed. The greatest value of total links and network density was achieved in the first match (88 total links and 0.80 of density value). Degree centrality revealed that the defenders and midfielders were the players with greatest prominent values in the attacking building. Degree prestige showed that midfielders were the main targets of the team to pass the ball in the attacking process. In summary, this study showed that centrality metrics can be an important tool in match analysis to identify the style of play of football teams, revealing the most prominent tactical roles in the attacking process.
  • Inspecting the collective behaviours : a survey for football teams
    Publication . Manuel Clemente, Filipe; M. L. Martins, Fernando; Couceiro, Micael; Mendes, Rui
    The collective behaviour on football teams has been widely studied in the last few years, after decades of a deeper study about the technical and physical demands of the football. Now a days a new approach for the match analysis has been possible using the new technological advances from the multiplayer tracking systems. Therefore, the aims of this study is to provide a summarized analysis of the tactical metrics proposed and used in the last few years, trying understand how can these metrics help the match analysis. Thus, the main goal is to provide a practical perspective for the collective behaviour analysis.
  • Mathematical models to measure the variability of nodes and networks in team sports
    Publication . M. L. Martins, Fernando; Gomes, Ricardo; Lopes, Vasco; Silva, Frutuoso G. M.; Mendes, Rui
    Pattern analysis is a widely researched topic in team sports performance analysis, using information theory as a conceptual framework. Bayesian methods are also used in this research field, but the association between these two is being developed. The aim of this paper is to present new mathematical concepts that are based on information and probability theory and can be applied to network analysis in Team Sports. These results are based on the transition matrices of the Markov chain, associated with the adjacency matrices of a network with n nodes and allowing for a more robust analysis of the variability of interactions in team sports. The proposed models refer to individual and collective rates and indexes of total variability between players and teams as well as the overall passing capacity of a network, all of which are demonstrated in the UEFA 2020/2021 Champions League Final.
  • Midfielder as the prominent participant in the building attack : a network analysis of national teams in FIFA World Cup 2014
    Publication . Manuel Clemente, Filipe; M. L. Martins, Fernando; Wong, P. Del; Kalamaras, Dimitris; Mendes, Rui
    This study aimed to analyze the most prominent players’ positions that contributed to the build of attack in football during FIFA World Cup 2014. The connections among teammates in all matches of the tournament were analyzed, and the tactical lineup and players’ positions of players were codified as independent variables. Four centrality network metrics were used to identify the pertinence of each players’ position. A total of 37,864 passes between teammates were recorded. Each national team was analyzed in terms of all their matches, thus all 64 matches from the FIFA World Cup 2014 tournament were analyzed and codified in this study. A total of 128 adjacency matrices and corresponding network graphs were generated and used to compute the centrality metrics. Results revealed that the players’ position (p = 0.001; η2p = 0.143; Power = 1.00; moderate effect size) showed significant main effects on centrality measures. The central midfielders possessed the main values in all centrality measures in the majority of analyzed tactical lineups. Therefore, this study showed that independent of the team strategy, the players’ position of a central midfielder significantly contributed to the build of attack in football, for example, greater cooperation and activity profile.
  • Analysis of scored and conceded goals by a football team throughout a season : a network analysis
    Publication . Santos, Agostinho; M. L. Martins, Fernando; Mendes, Rui
    Network analysis can provide a new set of important information about players and teams’ behaviour throughout a match. Despite their pertinence, football analysis using network metrics is limited. Therefore, the aim of this study was to analyse the goals scored and goals conceded by a single team during a full season using network methods. Thirty-six games were analysed and from these the data about players’ connectivity in actions preceding 46 goals scored and 15 goals conceded were collected. The results showed that the most used players during the plays that resulted in the goals scored were forward players in the forward regions, mainly in the penalty area. The lateral defenders and midfield players were the players that mostly initiated the attacking plays that resulted in the goals scored. In sum, it was possible to conclude that network metrics can provide a new visualization and understanding of team-members’ behaviour, as well as characterize some patterns of play giving sport’s analysts information complementary to the traditional notational analysis.