A Hybrid Ultra-Wideband and Inertial Measurement Unit Sensor System Can Accurately Measure the Sprinting Performance in Young Male Soccer Players

Background: This study investigated the concurrent validity and agreement of a hybrid ultra-wideband (UWB) and inertial measurement unit (IMU) wearable sensor system (K-Power) against criterion photocell timing gates during a 30 m sprint test, while secondarily exploring associations between 30 m sprint time (t30) and horizontal force–velocity (F-V) profile parameters in youth soccer players. Methods: Eighteen semi-professional male U19 soccer players executed three maximal 30 m sprints on an outdoor grass field. Sprint split times (0–10 m, 10–20 m, 20–30 m, and 0–30 m) were recorded simultaneously using the K-Power system (200 Hz) and four pairs of electronic timing gates. Mechanical F-V parameters—maximal theoretical force (F0), maximal theoretical velocity (V0), and maximal mechanical power (PMAX)—were derived from the sensor data. Concurrent validity was assessed using bias, limits of agreement (LoA), Pearson’s correlation, and intraclass correlation coefficients (ICC{A,1}). Relationships among parameters were evaluated using Kendall’s correlation. Results: The K-Power system demonstrated excellent absolute agreement for total sprint time (t30; ICC = 0.967; mean bias = –0.011 s) and strong correlations across all split intervals (r = 0.921 to 0.974). No proportional bias was observed. Regarding the F-V profile, t30 exhibited moderate negative correlation with PMAX (τb = −0.428, p = 0.015). Conclusions: The hybrid UWB-IMU sensor system is a valid and practical field-based tool for monitoring linear sprint performance and mechanical capabilities in soccer. Furthermore, sprint performance in youth soccer players over 30 m is primarily associated with maximal power capabilities during the initial steps rather than V0.