Determining the neuromuscular and energetic requirements of loaded and unloaded sprint efforts through experimental modeling new integrated approaches
Sprinting is a critical component of performance in soccer, necessitating a comprehensive understanding of the neuromuscular and metabolic demands placed on athletes during high-intensity actions. Despite the widespread use of Global Positioning System (GPS) technology in monitoring these demands, discrepancies between GPS-derived data and physiological responses measured through electromyography (EMG) suggest that current methods may underestimate/overestimate the effective intensity of sprinting efforts. This Doctoral Thesis aims to bridge this gap by providing a detailed analysis of sprinting performance in elite youth soccer players, utilizing GPS and EMG methodologies. The research is structured around four interconnected studies, each contributing to a deeper understanding of the factors influencing sprint performance and offering practical applications for optimizing training in soccer. Objective. The primary objective of this thesis is to evaluate the neuromuscular and metabolic demands of sprinting in soccer players using advanced assessment techniques. Specifically, the thesis aims to compare GPS and EMG-derived metrics in various sprinting conditions, analyze muscle activation patterns under different loading conditions, explore the utility of isometric and dynamic strength measures, and investigate the distinct demands of acceleration, high-speed running and deceleration. Methodology. Study 1 compares GPS and EMG methodologies for calculating metabolic power (MP) and energy cost (EC) during sprinting. Sixteen elite U17 soccer players participated in this study, performing submaximal runs and sprints while being monitored through portable GPS-IMU units and surface EMG. The findings reveal significant differences between the two methods, with EMG providing a more accurate representation of the energetic commitment required during sprints. Study 2 examines muscle activation patterns and the effects of various resistance sprints. Seventeen elite U17 soccer players completed sprints under unloaded and loaded conditions, with parachute and sled weights ranging from 15 to 60 kg. The results demonstrate that increasing load alters muscle percentage recruitment, with external metrics underestimating the demands compared to internal metrics (EMG), particularly under heavier load conditions. Results. The studies consistently demonstrate that EMG provides a more accurate measure of the neuromuscular and metabolic demands of sprinting compared to GPS-IMU-derived metrics. This is particularly evident in conditions involving higher resistive loads and complex movement patterns such as high-intensity actions. The analysis covers critical insights into the specific neuromuscular requirements of different sprinting actions, offering practical applications for optimizing training methodologies and empowering coaches and researchers with new knowledge. Conclusion. This advances the field of sports science by offering a more detailed analysis of the neuromuscular and metabolic demands of typical movements in soccer (such as sprints). Integrating GPS and EMG technologies, alongside innovative assessment methods, provides a comprehensive framework for understanding and improving sprint performance in elite youth soccer players. The findings underscore the need for individualized training strategies that accurately reflect effective efforts, ultimately contributing to enhanced athletic performance.
Energy cost, Metabolic power, Apparent efficiency, Soccer players, Sport performance, Coste energético, Potencia metabólica, Eficiencia aparente, Futbolistas, Rendimiento deportivo
Universidad Catolica de Murcia - Doctoral
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