Fahui WANG, Christophe HAUTIER, Lin SONG, Yong ZHOU, Brice GUIGNARD, Paul GLAISE, Qingshan ZHANG
Journal of Sports Science & Medicine - 2026;25(2):536-546
The objective was to determine the test-retest reliability and concurrent validity of a drone system in comparison to a radar device. Seventeen male collegiate soccer players participated in two maximal 30-meter sprint runs. The test-retest reliability of the drone system was evaluated using intraclass correlation coefficients (ICC 3,1), coefficient of variation (CV%), and standard error of measurement (SEM). Subsequently, the systematic bias and consistency of the two devices on various force-velocity (F-V) variables (e.g., maximal velocity [V max], theoretical maximal horizontal velocity [V 0], theoretical maximal horizontal force [F 0], the slope of the F-V relationship [S FV]) were evaluated using linear mixed model (LMM) and Bland-Altman analysis. The drone system demonstrated moderate to excellent test-retest reliability across all variables (0.59 <= ICC <= 0.95; CV% < 10%). While LMM analysis detected significant systematic differences for V max (p = 0.013) and V 0 (p = 0.012), Bland-Altman analysis confirmed high practical agreement with minimal bias (<= 1.12%) and narrow limits of agreement (LoA < 10%). P max, split times (T 5m-T20m) and average accelerations (A 10m-A20m) demonstrated greater consistency (%Bias <= 1.54%) with no significant systematic bias ( p > 0.05). Conversely, early-acceleration and model-derived metrics ( Tau, A max, F0, SFV) exhibited significant bias ( p <= 0.028) and wide LoA exceeding 10% (e.g., F 0: -13.37% to 8.56%; S FV: -11.54% to 18.18%). In conclusion, although the drone system exhibits high monitoring value in the maximum speed phase, early-acceleration metrics ( e.g., Amax, F0, and T 5m) should be interpreted with caution for individual-level monitoring. The tracking instability during the early acceleration phase necessitates further algorithm optimization.
