Psychological and physiological monitoring in elite soccer players: an interdisciplinary approach

The purpose of this PhD thesis was to advance the validation process of different monitoring tools aimed at quantifying training loads and athlete responses in elite soccer players. Three complementary studies were conducted across multiple competitive seasons with professional players. The first study examined the construct validity of a new aerobic field test (Intermittent Recovery Test or IRT), assessing its ability to represent the external load imposed on players during training and match activities. The second study focused on sleep monitoring, providing evidence of convergent validity by investigating the sleep quality. The third study implemented a six-week follow-up design to evaluate the relationships between physical and mental training loads, mood (BRUMS total mood disturbance and the Main & Grove questionnaire), perceived exertion (differentiated RPE), and changes in physical performance tests, thereby addressing aspects of convergent validity among subjective and objective monitoring tools. Collectively, these studies provide robust evidence supporting the application of integrated monitoring approaches in elite soccer players. The findings support the combined use of IRT indices, sleep assessments, and differential training load measures as valid indicators for athletes. Finally, this research offers practical implications for daily practice, highlighting the importance of integrating physical and psychological markers to optimize training prescription and minimize the risk of maladaptation.