Validity of 10-HZ GPS and Timing Gates for Assessing Maximum Velocity in Professional Rugby Union Players

Purpose: The purpose of this study was to investigate the validity of timing gates and 10-Hz global positioning systems (GPS) units (Catapult Optimeye S5) against a criterion measure (50-Hz radar gun) for assessing maximum sprint velocity (V-max). Methods: Nine male professional rugby union players performed 3 maximal 40-m sprints with 3 min rest between efforts with Vmax assessed simultaneously via timing gates, 10-Hz GPS(open) (Openfield software), GPS(sprint) (Sprint software), and radar gun. Eight players wore 3 GPS units, while 1 wore a single unit during each sprint. Results: When compared with the radar gun, mean biases for GPS(open), GPS(sprint), and timing gates were trivial, small, and small, respectively. The typical error of the estimate (TEE) was small for timing gate and GPS(open) while moderate for GPS(sprint). Correlations with radar gun were nearly perfect for all measures. Mean bias, TEE, and correlations between GPS units were trivial, small, and nearly perfect, respectively, while a small TEE existed when GPS(Openfield) was compared with GPS(sprint). Conclusion: Based on these findings, both 10-Hz GPS and timing gates provide valid measures of 40-m V-max assessment compared with a radar gun. However, as error did exist between measures, the same testing protocol should be used when assessing 40-m V-max over time. Furthermore, in light of the above results, it is recommended that when assessing changes in GPS-derived V-max over time, practitioners should use the same unit for each player and perform the analysis with the same software, preferably Catapult Openfield.