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 V max 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.