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- New technologies to the study the golf puttingPublication . Fernandes, Orlando; Dias, Gonçalo; Couceiro, Micael; Manuel Clemente, Filipe; M. L. Martins, Fernando; Luz, Miguel; Mendes, RuiThe technology evolution, especially in the last decade, allowed major advances in golf putting analysis. This scientific advance benefited from multidisciplinary interaction, such as: biomechanics, engineering, mathematics and motor control. Utilizing digital cameras along automatic tracking techniques, it is possible to obtain valuable and accurate information about the putting gesture and/or ball trajectory. This can provide relevant feedback to athletes and coaches. In this work, we present several golf putting studies conducted on laboratorial environment. We believe that this work may contribute to a deeper analysis of human motor behavior and performance, not limited to this motor skill, but that can be applied to other motor patterns.
- Team’s performance on FIFA U17 World Cup 2011 : study based on notational analysisPublication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, RuiThe 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.
- Measuring collective behaviour in football teams : inspecting the impact of each half of the match on ball possessionPublication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, Rui; Figueiredo, AntónioThe aim of this study was to inspect the influence of each half of matcha and the ball possession status on the players’ spatio-temporal relationships. Three official matches of a professional football team were analysed. From the players' locations were collected the team’s wcentroid, wstretch index, surface area and effective area of play at 9218 play instants. The results suggested that the values of teams’ dispersion and average position on the field decreases during the 2nd half of the match. In sum, this study showed that the half of match and the ball possession status influenced players’ spatio-temporal relationships, in a way that significantly contributes to the collective understanding of football teams.
- Study of the heart rate and accuracy performance of archersPublication . Manuel Clemente, Filipe; Couceiro, Micael; Rocha, Rui; Mendes, RuiOn archery performance, heart rate variability is associated to higher parasympathetic activity and a better balance of parasympathetic and sympathetic are beneficial to performance within the sport (Lo, Huang & Hung, 2008). The purpose of this study was to compare heart rate and archery accuracy in experienced and inexperienced archers as to determine if experience contributes to increased accuracy and decreased heart rate. Eighteen male individuals (23.2 ± 5.3 years) participated. The task consisted in the realization of archery, aiming to achieve higher scores corresponding to greater accuracy in target. Twelve trials were performed at two blocks (i.e., total of twenty-four trials) by each participant. At each archery attempt, we collected the heart rate immediately before the trial and the respectively accuracy of archery performance. The t-independent test showed significant statistical differences on heart rate (t(430) = - 4.135, p-value = 0.001) and score of archery performance (t(430) = 2.745, p-value = 0.006), between experienced and inexperienced archers. Experienced archers exhibit a better accuracy and at same time a less heart rate comparing to inexperienced archers. It is possible that the experience of the archers help to improve the arousal control and, consequently, balance between sympathetic and parasympathetic systems.
- Posicionamento angular do atacante em relação ao defensor em futebolistasPublication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Dias, Gonçalo; Mendes, RuiO presente estudo objetivou analisar as amplitudes angulares do atacante em relação ao defensor ao longo da série temporal de prática, tentando verificar se tal parâmetro contribui para a quebra da estabilidade da díade atacante-defensor. Participaram 11 futebolistas (17,91 ± 1,04 anos de idade) com 8,6 ± 1,52 de anos de prática. De forma a entender a relação da posição entre o atacante e o defensor, procedeu-se ao cálculo do posicionamento angular entre ambos. Para o efeito, considerou-se o ângulo 0º como sendo o ângulo entre o atacante e o defensor quando estes formam uma linha perpendicular à aresta do campo onde se encontra a baliza estando o defensor mais próximo da mesma. Os resultados indicam uma oscilação regular por parte do atacante no sentido de procurar desequilibrar o oponente sendo que, através dessa ação reação o atacante procura encontrar novas soluções que resultem da exploração do meio e do adversário.
- Using artificial intelligence for pattern recognition in a sports contextPublication . Rodrigues, Ana Cristina; Pereira, Alexandre Santos; Mendes, Rui; Araújo, André Gonçalves; Couceiro, Micael; Figueiredo, António J.Optimizing athlete’s performance is one of the most important and challenging aspects of coaching. Physiological and positional data, often acquired using wearable devices, have been useful to identify patterns, thus leading to a better understanding of the game and, consequently, providing the opportunity to improve the athletic performance. Even though there is a panoply of research in pattern recognition, there is a gap when it comes to non-controlled environments, as during sports training and competition. This research paper combines the use of physiological and positional data as sequential features of different artificial intelligence approaches for action recognition in a real match context, adopting futsal as its case study. The traditional artificial neural networks (ANN) is compared with a deep learning method, Long Short-Term Memory Network, and also with the Dynamic Bayesian Mixture Model, which is an ensemble classification method. The methods were used to process all data sequences, which allowed to determine, based on the balance between precision and recall, that Dynamic Bayesian Mixture Model presents a superior performance, with an F1 score of 80.54% against the 33.31% achieved by the Long Short-Term Memory Network and 14.74% achieved by ANN.
- Using network metrics to investigate football team players’ connections : a pilot studyPublication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, RuiThe 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.
- The usefulness of small-sided games on soccer trainingPublication . Manuel Clemente, Filipe; Couceiro, Micael; M. L. Martins, Fernando; Mendes, RuiThe specificity of collective sports training has evolved to adapt according to ecology stimuli inherent to the sport. In this sense, the coaches have adopted exercises based on the game, designated by small-sided games. In football practice this type of exercises triggers very receptivity on the part of coaches. In this sense, this paper analyzes the relevance of this type of exercise and as may be appropriate depending on the specific needs of the players. Task constraints as field dimensions, number of players for exercises or objectives of the task showed effects on physiological and technical variables of the players. Consequently this article will examine through a literature review, the effects related to the task constraints in order to emphasize the massive relevance of smallsided soccer games.
- The variability of the serve toss in tennis under the influence of artificial crosswindPublication . Mendes, Pedro C.; Fuentes, Juan P.; Mendes, Rui; M. L. Martins, Fernando; Manuel Clemente, Filipe; Couceiro, MicaelThis study was made to analyze the variability and stability of the serve toss in tennis, on the x (side-to-side), y (back-to-front) and z (vertical) axes, with 12 experienced players under the influence of crosswind (induced aerodynamic flow) produced by an industrial ventilator. The players were analyzed individually after serving at maximum speed and accuracy to the intersection point of the centre line and service line ("T" point). The results allow us to conclude that the experienced players tend to stabilize the vertical dimension of the service (z axis). Additionally, this study confirms the invariability of the player height ratio: height of impact (1:1.5) in experienced players even when constrained by the "artificial crosswind." Given the above, the vertical dimension of the tennis serve is assumed as a constant feature, which is guaranteed in the remaining varying dimensions (y and x axes) of the ball toss. Thus, the variability should be seen as part of the solution and not as something to be avoided by players and coaches.
- Video analysis of left and right breaking puttsPublication . Dias, Gonçalo; Mendes, Rui; Couceiro, Micael; Gomes, Ricardo; Manuel Clemente, Filipe; M. L. Martins, FernandoThe aim of this study was to investigate how a player responds to external constraints (slope and angle) in a golf putting task. The sample consisted of 10 adult male (33.8 ± 11.89 years), right handed and highly skilled golfers (average handicap of 10.82). The participants performed 30 putts at a distance of two meters with 25 degrees to the left of the hole (Angle 1) and 30 putts at a distance of two meters with 25 degrees to the right of the hole (Angle 2), with a constraint imposed by a slope. The data suggests that the performance of the golf putting may be improved if different situations and difficulty degrees are employed and exploited. In that sense, the manipulation of task related constraints forced the appearance of solutions uniquely adjusted to each player. This brings implications to the area of sports coaching and training, considering that the athlete can optimize his performance if he explores different couplings of information-movement, in different levels of complexity.