Samenvatting

The stretch-shortening cycle (SSC) plays a crucial role in explosive sports movements. Neuromuscular fatigue, measured via the Reactive Strength Index (RSI), affects this performance.
In the context of football, monitoring external load is essential for understanding fatigue. Although previous studies have shown associations between load and fatigue, the predictive value of GPS data on neuromuscular fatigue remains underexplored. The aim of this study is to predict neuromuscular fatigue based on external load, with the expectation that sprint distance would have the greatest impact on neuromuscular fatigue. In this study, pre- and post-scores on RSI were measured using the 10/5 repeated jump test in 29 male youth football players. External load was recorded using GPS systems. A multiple regression analysis was then conducted to examine the relationship between various load variables and the change in RSI. The regression model showed a significant relationship between external load and RSI change (p = 0.002), explaining 11.5% of the variance (R² = 0.115). The hypothesis that sprint distance would be the most influential factor was not confirmed; total distance turned out to be the strongest predictor of fatigue. The limited variance suggests that other factors such as motivation, sleep, nutrition, and hydration are also important. Applying the model in practice can contribute to injury prevention and performance optimization. Future research could focus on larger samples, more measurements at higher sprint volumes, and optimal load in different types of training.