Abstract / Summary
Reaction time is central to sprint events and the basis of the false-start rule (0.100 s) of World Athletics. We analysed 1558 official reaction times collected during the 100 m and short hurdle events at five World Championship meetings (London 2017, Doha 2019, Eugene 2022, Budapest 2023, Tokyo 2025) and found that three world championship meetings were statistically equivalent (i.e., London 2017, Doha 2019, and Budapest 2023) with an average reaction time between 154.7 ms and 156.0 ms, and two world championships with large deviations from the others: Eugene 2022 had on average 18.8 ms faster reaction times than the baseline, while Tokyo 2025 averaged 24.9 ms slower ( | d | = 0.85 and 1.06 , respectively, both p < .001 ; 2022 vs. 2025 d = − 1.88 ). Both of these outliers were observed throughout the entire distribution and remained when the same athletes were compared across championships, ruling out cohort-related differences. These bidirectional differences are difficult to reconcile with athlete physiology and are most consistent with championship-level differences in how reaction time is measured, although the specific technical source cannot be identified from the public data. We strongly recommend that World Athletics establish calibration standards for all timing systems similar to those outlined in Technical Rule 16.6 and store raw force-time data for all athletes for independent auditing purposes.