Match activity analysis of soccer referees using electrocardiogram, GPS and clustering algorithms

Referee is one of the main factors of a soccer game. During the game, referee is responsible to protect players' health and to ensure proper implementation of the rules. In order to be able to achieve these tasks, referee needs to have tremendous physical and mental fitness, has to be able to interpret events according to the spirit of the game of the rules and needs to be control the area where the ball is played. Due to the constant change in direction and speed of the game, comparative analysis of movement patterns is important for the assessment of the physiological stress and effort exerted to the referees. Additionally, the heart rate response is analyzed as an indicator of physiological stress. Although there are several studies on performance of soccer referees, studies are typically limited to the analysis of the distance covered by the referees during the games. In this thesis, analysis of 1) running styles of the referees, 2) duration, 3) how well the referees are using diagonal running style and field usage, 4) activities performed in various periods of the games and heart rate change with the activity, were performed. In this study, field dimensions and positions of field line markings were obtained by using global positioning system. Midfield line and midpoint were estimated based on the field lines. Simultaneous recording of the coordinates of the referees and heart rate were recorded and analyzed. Running styles were divided into several groups and statistical analysis was performed.