Over the last years there has been a substantial growth in research related to specific training methods in soccer with a strong emphasis on the effects of small-sided games. The increase of research in this topic is coincident with the increase of popularity obtained by specific soccer conditioning, which involves training players to deal with soccer match situations. Given the limited time available for fitness training in soccer, the effectiveness of small-sided games as a conditioning stimulus needs to be optimized to allow players to compete at the highest level. Available studies indicate that physiological responses (e.g. heart rate, blood lactate concentration and rating of perceived exertion), tactical and technical skill requirements can be modified during small-sided games by altering factors such as the number of players, the size of the pitch, the rules of the game, and coach encouragement. However, because of the lack of consistency in small-sided games design, player fitness, age, ability, level of coach encouragement, and playing rules in each of these studies, it is difficult to make accurate conclusions on the influence of each of these factors separately.

Tactical match performance depends on the quality of actions of individual players or teams in space and time during match-play in order to be successful. Technological innovations have led to new possibilities to capture accurate spatio-temporal information of all players and unravel the dynamics and complexity of soccer matches. The main aim of this article is to give an overview of the current state of development of the analysis of position data in soccer. Based on the same single set of position data of a high-level 11 versus 11 match (Bayern Munich against FC Barcelona) three different promising approaches from the perspective of dynamic systems and neural networks will be presented: Tactical performance analysis revealed inter-player coordination, inter-team and inter-line coordination before critical events, as well as team-team interaction and compactness coefficients. This could lead to a multi-disciplinary discussion on match analyses in sport science and new avenues for theoretical and practical implications in soccer.

Identifying match statistics that strongly contribute to winning in football matches is a very important step towards a more predictive and prescriptive performance analysis. The current study aimed to determine relationships between 24 match statistics and the match outcome (win, loss and draw) in all games and close games of the group stage of FIFA World Cup (2014, Brazil) by employing the generalised linear model. The cumulative logistic regression was run in the model taking the value of each match statistic as independent variable to predict the logarithm of the odds of winning. Relationships were assessed as effects of a two-standard-deviation increase in the value of each variable on the change in the probability of a team winning a match. Non-clinical magnitude-based inferences were employed and were evaluated by using the smallest worthwhile change. Results showed that for all the games, nine match statistics had clearly positive effects on the probability of winning (Shot, Shot on Target, Shot from Counter Attack, Shot from Inside Area, Ball Possession, Short Pass, Average Pass Streak, Aerial Advantage and Tackle), four had clearly negative effects (Shot Blocked, Cross, Dribble and Red Card), other 12 statistics had either trivial or unclear effects. While for the close games, the effects of Aerial Advantage and Yellow Card turned to trivial and clearly negative, respectively. Information from the tactical modelling can provide a more thorough and objective match understanding to coaches and performance analysts for evaluating post-match performances and for scouting upcoming oppositions.

The aim of this study was to examine the effect of match location, quality of opposition, and match status on distance covered at various speeds in elite soccer. Twenty-seven Spanish Premier League matches played by a professional soccer team were monitored in the 2005Á2006 season using a multiple-camera match analysis system. The dependent variables were the distance covered by players at different intensities. Data were analysed using a linear regression analysis with three independent variables: match status (i.e. whether the team was winning, losing or drawing), match location (i.e. playing at home or away), and quality of the opponents (strong or weak). The top-class players performed less high-intensity activity (19.1 km × h (1 ) when winning than when they losing, but more distance was covered by walking and jogging when winning. For each minute winning, the distance covered at submaximal or maximal intensities decreased by 1 m (P B0.05) compared with each minute losing. For each minute winning, the distance covered by walking and jogging increased by 2.1 m (P B0.05) compared with each minute losing. The home teams covered a greater distance than away teams during low-intensity activity (B14.1 km × h (1 ) (P B0.01). Finally, the better the quality of the opponent, the higher the distance covered by walking and jogging. Our findings emphasize the need for match analysts and coaches to consider the independent and interactive effects of match location, quality of opposition, and match status during assessment of the physical component of football performance.

Small-sided games are commonly used in training and teaching contexts of football. However, few studies have focused on the tactical implications of this type of drills. The aim of this study is to identify how tactical collective behaviour varies with age in different small-sided game formats. We investigated the in-game field position in three different age groups of youth football players [under-9 (n=10; age = 8.5 ± 0.53), under-11 (n=10; age = 10.4 ± 0.52) and under-13 (n=10; age = 12.7 ± 0.48)], participating in two different small-sided game conditions (GK + 3 × 3 + GK and GK + 4 × 4 + GK). A team variable was created based on the players' length per width ratio (lpwratio), and a match variable was calculated as the distance between the centroid of the two teams. Results show that team variable values were influenced by the age of the players, as younger teams tend to present a higher value of lpwratio in their dispersion on the pitch. The variability of this variable also showed a decrease for teams with older players, suggesting a more consistent application of the width (stretching and creating space) and concentration (compressing into a confined area) principles of play and reflecting a higher level of collective tactical behaviour. Match variable showed a larger centroid distance for the older age groups in comparison with the younger players in the GK + 3 × 3 + GK, while all age groups demonstrated similar large centroid distances in the GK + 4 × 4 + GK game format. These results suggest that length and width ratio and centroid distance are useful measures of tactical performance in small-sided games in youth football.