Efecto de la modificación de las reglas de juego sobre la frecuencia cardiaca, las acciones técnico-tácticas, la cooperación y la autoeficacia en jugadores de fútbol en etapas de formación

Abstract

The aim of this dissertation was to analyse the effect of a series of rules modifications in the competition format on the different factors that determine the training process of youth football players (U-12): physical, technical-tactical and psychological. To this end, a total of six studies have been carried out in this dissertation: Study I: The aim of this study was to design, validate and assess the reliability of a mixed observation instrument of field formats and category systems to analyse technical and tactical actions in the offensive phase in football. The instrument design, validation and reliability calculations were done in four stages: a) literature review, b) design of the first draft of the instrument, c) qualitative and quantitative review, and d) reliability calculation. Content validity was established by 12 experts (PhD in Sport Science or football coach with at least 10 years of coaching experience). The Delphi methodology was used. The lowest Aiken's V index was 0.91. The lowest Kappa index was 0.96 for inter-reliability and was 0.98 for intra-reliability. The coefficients of the generalizability analysis showed a high level of accuracy, validity and reliability. Study 2: The purpose was to analyse the impact of rule changes associated with Non-Linear Pedagogy on the levels of physical activity (heart rate) in the development of tasks in youth football players (U-11). A quasi-experimental study was developed in which three tasks were applied using structural modifications of the elements of football related to Non-Linear Pedagogy (number of players (situations of inferiority, equality and numerical superiority); dimensions of the field of play). The results showed very high levels of vigorous and very vigorous physical activity in all the designed tasks. Study 3: The aim of this study was to analyse the effect of the reduction of the number of players (from 8 per team to 5 per team), the size of the goal (from 6 x 2 m to 3 x 2 m) and the playing space (from 58 x 38 m to 38 x 20 m), on the technical and tactical actions of youth football players. A quasi-experimental A-B-A design was applied to evaluate the effect of the rule changes. Players (n= 40) participated in three tournaments using two competition formats (official rules, modified rules and official rules). The results show that the use of the modified rules generated a greater number and variability in the technical-tactical actions, a greater number of actions with teammates in the passing line, a greater continuity in the game, a greater number of attacking and defending actions in areas around the goal, and favours the team play actions. Study 4: The purpose of this study was to evaluate the effect of modifications in field size, number of players and goal size on goalkeeper actions in competition in formative male football (n = 4) (U-12). A quasi-experimental design was implemented to measure the effects of changes in the number of players per team (8 vs 8 vs 5 vs 5), goal size (6 x 2 m vs 3 x 2 m), and field dimensions (58 x 38 m vs 38 x 20 m) on the goalkeeper's offensive and defensive technical-tactical actions. They were analysed in three tournaments (8 vs 8; 5 vs 5; 8 vs 8). The results show that in 5-a-side football matches, goalkeepers performed more defensive actions and offensive actions than in 8-a-side football. The reduction in field size, number of players and size of goals meant that the U-12 goalkeepers had more interaction and more variability in their actions. Study 5: The aim of this study was to evaluate the short-term effect of modifying the number of players, field size and goal size on the levels of physical self-efficacy, soccer-specific self-efficacy and collective self-efficacy in young U-12 male football players (n=48). A quasi-experimental A-B-A (official rules - experimental rules - official rules) study was implemented to measure the effect of rule changes on player self-efficacy. Players' technical-tactical actions such as clearances, passes and shots were measured as adjuvant variables to assess the implication of the modification of the rules of the game. The experimental rules did not change players' overall physical self-efficacy and collective self-efficacy. The experimental rules implied the performance of more defensive actions (clearances) and offensive actions (passing and shooting) by the players. The results showed that both competition rules implied similar self-efficacy values. Study 6: The aim of this study was to analyse the effects of changing field size, goal size and number of players per team on the level of cooperation of youth football players (U-12). A quasi-experimental design was implemented to measure the effects of changes in the number of players per team (8 vs 8 vs 5 vs 5 vs 5), goal size (6 x 2 m vs 3 x 2 m), and field size (58 x 38 m vs 38 x 20 m) on cooperation. Four U-12 football teams (n = 48 players) participated in three tournaments (standard rules; experimental rules; standard rules). The five cooperation variables were measured using the "Sport Cooperation Questionnaire. Players showed the same level of cooperation in conditional cooperation, situational cooperation with teammates and situational cooperation outside the playing field with both types of rules. The modification of the rules implied a reduction of cooperation with the coach and the readiness of unconditional cooperation. The causes of the reduction may be related to the adaptation of the players to the new tactical dispositions and game situations. The long-term athletic development of the youth player is a complex process in which multiple factors have a direct impact on the youth player. The results of this dissertation show that the modifications of the structural elements of football used have a positive effect on the long-term athletic development.