Using Multivariate Adaptive Regression Splines in the Construction of Simulated Soccer Team's Behavior Models

In soccer, like in other collective sports, although players try to hide their strategy, it is always possible, with a careful analysis, to detect it and to construct a model that characterizes their behavior throughout the game phases. These findings are extremely relevant for a soccer coach, in order not only to evaluate the performance of his athletes, but also for the construction of the opponent team model for the next match. During a soccer match, due to the presence of a complex set of intercorrelated variables, the detection of a small set of factors that directly influence the final result becomes almost an impossible task for a human being. In consequence of that, a huge number of software packages for analysis capable of calculating a vast set of game statistics appeared over the years. However, all of them need a soccer expert in order to interpret the produced data and select which are the most relevant variables. Having as a base a set of statistics extracted from the RoboCup 2D Simulation League log files and using a multivariable analysis, the aim of this research project is to identify which are the variables that most influence the final game result and create prediction models capable of automatically detecting soccer team behaviors. For those purposes, more than two hundred games (from 2006-2009 competition years) were analyzed according to a set of variables defined by a soccer experts board, and using the MARS and RReliefF algorithms. The obtained results show that the MARS algorithm presents a lower error value, when compared to RReliefF (from a pairwire t-test for a significance level of 5%). The p-value for this test was 2.2e-16 which means these two techniques present a significant statistical difference for this data. In the future, this work will be used in an offline analysis module, with the goal of detecting which is the team strategy that will maximize the final game result against a specific opponent

Concepções de treinadores "experts" Brasileiros sobre o processo de formação desportiva do jogador de voleibol Expert coaches conceptions concerning the sport development of the volleyball player

O presente estudo teve como objetivo examinar a concepção de treinadores experts acerca das etapas de formação desportiva a longo prazo do jogador de Voleibol. A amostra do estudo foi composta por 10 treinadores "experts" brasileiros. Os sujeitos apresentaram idade média de 45 ± 13,8 anos e 24,8 ± 12,1 anos de experiência profissional, sendo todos licenciados em Educação Física. Os dados foram coletados por meio de entrevista estruturada e de resposta aberta, baseada no protocolo de Fernandes (2004). A sua adaptação de conteúdo à realidade sócio-cultural e desportiva brasileira foi efetivada pelo método de peritagem. O tratamento das informações foi realizado por meio da análise de conteúdo, com o recurso à interpretação lógico-semântico das ideias prevalecentes no "corpus" das entrevistas. A fidedignidade de codificação foi assegurada pela percentagem de acordos, para o mesmo codificador e codificadores distintos, situando-se os valores registrados entre 95% e 100%. Os resultados revelaram o desconhecimento, por parte dos investigados, acerca da existência de um modelo de formação desportiva do voleibolista, a longo prazo, no Brasil. Além de confirmarem que o Voleibol é uma modalidade de especialização tardia, os participantes do estudo apontam que a idade de iniciação da sua prática sistemática se situa no início da adolescência, por volta dos 13 anos. As componentes de desenvolvimento desportivo acentuam a prática do jogo deliberado na primeira etapa, onde as experiências motoras diversificadas prevalecem. A partir da segunda etapa aumenta a prática deliberada, com o incremento da aquisição de competências específicas e o comprometimento com a modalidade. A ausência de especificação dos conteúdos de treino ao longo das etapas, bem como a parca referência às competências psico-sociais pode dever-se, em grande medida, à possível inexistência de um modelo nacional referenciador da formação desportiva a longo prazo do jogador de Voleibol.<br>The aim of the present study was to examine the conceptions of expert coaches concerning the volleyball player's long term sport development. The participants were 10 expert coaches. The sample presented 45 ± 13.8 years old and 24.8 ± 12.1 years of coaching experience in the Brazilian volleyball. Data collection was accomplished through structured open answer interviews based on Fernandes' protocol (2004). Its content adaptation to sociocultural and sportive Brazilian reality was accomplished through expert validation. The treatment of the information was accomplished through content analysis, with logic-semantic procedures of the prevalent ideas in the corpus of interviews. The reliability of codification was assured by percentage accord of the same encoder and the different encoders, registering values between 95% and 100%. The present study evidences that no participant knows about the existence of a national long term sport development model for a volleyball player. Moreover, coaches confirmed that the Volleyball is a sport of late specialization, being a widespread consensus that the age of initiation of systematic practice is in the beginning of adolescence, around the age of 13 years old. The components of sport development throughout the stages highlight the practice of the deliberate play in the first stage, where diversified motor experiences prevail. From the second stage, the deliberate practice increases with the acquisition of specific competences and commitment with the modality. The absence of specification of the training contents along the stages, as well as the scanty reference to the psychosocial competences along the stages, can be due, in great measure, to the inexistence of a national model of long term sport development