Análisis de la fuerza centrípeta como parámetro de carga externa en fútbol

Abstract

In team sports, and especially in football, non-linear movements are important to soccer performance. Nowadays, thanks to technological advances, it is possible to monitor them through the combination of microelectromechanical sensors and tracking technologies in indoor (ultra-wideband, UWB) and outdoor conditions (global positioning system, GPS). Therefore, the purposes of this doctoral thesis were: (i) to analyse the accuracy, reliability and comparison between tracking technologies of an electronic performance and tracking system (EPTS) for the measurement of centripetal force during curvilinear movements in football; (ii) to describe the demands of direction changes and centripetal force generated by elite-level soccer players in official competition and to identify the influence of anthropometric characteristics, playing position, laterality, and playing area on the field of play on non-linear displacements; and (iii) to analyse the influence of the phase of the season, the type of competition, the final result, the place where the competition takes place and the field of play on the demands of direction changes and centripetal force during matches. First, to answer the objective 1, a circuit with specific curvilinear movements was designed for the detection of centripetal force using GPS and UWB to compare its data with the real measurements (measuring rod and time gates). For the objectives 2 and 3, thirty professional footballers (age: 26.57 ± 5.56 years) were monitored during the 2017-2018 season in friendly, national and international matches (38 total matches) through an EPTS called WIMU PROTM (RealTrack Systems, Almeria, Spain) that was previously evaluated following the protocol of objective 1. In conclusion, (i) the evaluated EPTS presented a high reliability for the registering of centripetal force using UWB and GPS, so the data can be compared between devices with the same tracking technology, being the UWB that demonstrated to have a better accuracy for the assessment of non-linear displacements; (ii) the anthropometric characteristics, the playing position, the laterality and the field zone influenced the changes of direction and the centripetal force generated during the matches, because it is necessary to individualize the training workload related to non-linear displacements in football; and (iii) except for the playing surface, the contextual variables final result of the match, match location, type of competition and phase of the season modified the demands of centripetal force and changes of direction, making it necessary an adaptation of the design of training sessions and the workload planning of non-linear displacements along the microcycles during the season to improve competitive success.