Showing papers by "Martin Lames published in 2011"
TL;DR: There was a significant correlation between the relative age effect and success defined by teams' final rankings, and with a median of birth dates one month earlier the team is expected to finish 1.035 ranks better.
Abstract: The aim of the study was to determine whether there is empirical evidence for advantages in performance of soccer teams because of their relative age. The practice of selecting youth players according to their momentary performance leads to relative age effects, which in turn lead to inefficient talent selection. We used the median of the birth dates as a measure of the effect size of the relative age effect and the Kolmogorov-Smirnov test to assess its significance. For the 2008–2009 season, birth dates in the three German U-17 first leagues for soccer were examined (911 players). More than half of the 41 teams differed significantly from the distribution of the corresponding German cohort. There was a significant correlation between the relative age effect and success defined by teams' final rankings (Spearman's ρ = 0.328, P = 0.036). Regression analyses revealed that with a median of birth dates one month earlier the team is expected to finish 1.035 ranks better. Accordingly, selecting early b...
110 citations
TL;DR: In this article, the authors proposed the ISOPAR method for assessing the difficulty of shots in golf and a new performance indicator Shot Quality, which is defined as the difference between the starting position and finishing position, respectively.
Abstract: Classical performance analysis techniques in golf have focused on classes of shots, such as putting, driving, etc. Because these measures remove shots from their original context within the round, such measures do not describe a player's ability to perform a specific type of shot. Rather, these measures provide a score which is a composite score of all previous shots on the hole. This study establishes a new method for assessing the difficulty of shots in golf and a new performance indicator Shot Quality. We call our method the ISOPAR method, which gets its name from the analogy we make to isobar maps used in meteorology. The method presented here relies on ball positions taken from tournament play and the associated number of shots required to hole out from each measured ball position. Data were collected from the 2009 Bavarian Junior Championship in Burgwalden, Germany. ISOPAR values are calculated which represent the average number of strokes required to hole out from any location on the green. These ISOPAR values can be visualized on an ISOPAR map. Instead of lines of equal pressure, as in the case of our meteorological analogy, the lines on the map represent the ISOPAR values at intervals of 0.2. High values can be interpreted as difficult areas on the green and low values as easy areas on the green. The Shot Quality score is the difference between the ISOPAR values of the starting position and finishing position, respectively. ISOPAR maps could potentially be used by professional golfers and caddies to characterize a green in terms of areas of difficulty and may also help them decide which putts to play more or less aggressively. Television broadcasts could also use these maps to show the audience how the field fared from various positions on the green. Finally, coaches and teachers could use the Shot Quality measure as a new performance indicator to assess shot outcomes.
14 citations
DOI•
01 Jan 2011
TL;DR: This report documents the program and the outcomes of Dagstuhl Seminar 11271 ``Computer Science in Sport - Special emphasis: Football''.
Abstract: This report documents the program and the outcomes of Dagstuhl Seminar 11271 ``Computer Science in Sport - Special emphasis: Football''.
There were five sessions over the course of three days focusing on separate specific aspects on the relevance, applications and current issues pertaining to computer science in sport.
The first session on the first day was about RoboCup -- the history, types of games and robots used, and the current topics relevant to machine learning, tracking and planning.
The second session on the first day was a miscellaneous session, which looked at broad topics ranging from hardware devices for mobile coaching, uses of positional data in football, rehabilitation methodologies and games for learning.
The second day started with a session on modelling sports as dynamical systems combined with the use of neural networks in performance analysis as well as theoretical issues in human movement science.
In the afternoon of the second day the session was on topics in computer science specifically relevant to coaches, in which six different people presented.
The final day of the conference hosted a session on computer science ``behind the scenes'' of major sports broadcasters and other media.
The sessions were attended by academics, graduate students, coaches, performance analysts and athletes.
4 citations
01 Jan 2011
TL;DR: Based on ISOPAR maps the authors can visualize the affordances and constraints which influenced the field’s play and identify areas on the green where the play of the field was constrained heavily by gradients on the greens surface and/or distance to the cup.
Abstract: One of the main theories in ecological psychology is the theory of affordances. Affordances are opportunities for action which are provided by the environment in which the action takes place and are action specific. So affordances describe how the environment allows, supports and constrains an action. The idea of studying the affordances can also be applied to sport, in this case to putting in golf, to gain insight into how performance is influenced by the sport specific environment. During tournaments, discrete experiences of players while performing a putt were collected for several rounds at one green. Using the ISOPAR method (Stöckl et al., 2011) all the single experiences of one round of the different players were transformed into a continuous average experience of the field across the whole green. Based on ISOPAR maps we can visualize the affordances and constraints which influenced the field’s play. According to the number and the arrangement of the iso-lines on the ISOPAR maps we can identify areas on the green where the play of the field was constrained heavily by gradients on the green’s surface and/or distance to the cup.
4 citations
TL;DR: In this paper, an application of the ISOPAR method to performance analysis in golf has been presented, where the authors present an application to performance analistic analysis of the sport of golf.
Abstract: Performance analysis in golf has been hindered by a lack of valid performance indicators available. This paper presents an application of the ISOPAR method (Stockl et al., 2011) to performance anal...
3 citations
TL;DR: Findings prove that rankings of clubs from German Bundesliga were affected considerably by their releases to World Cup, and teams with many releases underperformed in the first half of the season whereas teams with few or no releases performed surprisingly well.
Abstract: The aim of the study was to analyse the influence of the 2010 World Cup for teams of the German Bundesliga that had to release from up to 13 to no players. For the 34th day of the 2009/10 season an...
1 citations
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01 Jan 2011
TL;DR: The ISOPAR method is a method for characterizing the difficulty of golf holes and allows the performance of shots to be analyzed as discussed by the authors. But it is not suitable for the use of shot locations.
Abstract: e ISOPAR method is a method for characterizing the difficulty of golf holes and allows the performance of shots to be analyzed. emethod is based on the ball locations provided by ShotLinkTMand the subsequent number of shots required to hole out from each respective location. ISOPAR values are calculated which represent the number of shots the field would require to hole out. ese ISOPAR values can, a) be visualized on an ISOPAR map and, b) lead to a new performance indicator called Shotality, which is the difference between the ISOPAR values of the starting position and finishing position, respectively. e Shot ality score can also be used to determine how many shots were saved per shot, or per type of shot, with respect to the performance of the field.