Validity and Reliability of a Novel Timing Gate System for Real-Time Measurement of Sprint Force-Velocity Profile

Nishioka, T, Yamaguchi, S, Hajima, D, Yabuno, N, Aoki, A, Kunita, Y, Hashimoto, Y, and Inami, T. Validity and reliability of a novel timing gate system for real-time measurement of sprint force-velocity profile. J Strength Cond Res XX(X): 000–000, 2026—The purpose of this study was to investigate the concurrent validity and intertrial reliability of a newly developed timing gate system, VoltOnoSprint (VOS), with a mat switch and smartphone app for real-time measurement of the sprint force-velocity (F-V) profile. Twenty-four men (age: 21.1 ± 2.1 years) performed two 30-m sprints. Subjects' body center of mass velocity and position-time data were measured simultaneously by radar and VOS, respectively, and were used to calculate the sprint F-V profile variables. All sprint F-V profile variables derived from VOS had significant, positive, and nearly perfect correlations ( r = 0.905 to 0.964) with radar measurements and did not differ significantly ( d = 0.073 to 0.110) from those derived from radar. The sprint F-V profile variables calculated using both systems exhibited acceptable intertrial reliability (intraclass correlation coefficient = 0.767 to 0.985, coefficient of variation = 0.88–4.81%), except for the relative reliability of one F-V profile variable (the slope of the F-V relationship) derived from radar. Furthermore, all sprint F-V profile variables derived from VOS had higher absolute variability than those derived from radar. These results suggest that VOS is a valid and reliable method for sprint F-V profiling, and the reliability of the sprint F-V profile variables measured by VOS was superior to that measured by radar, a criterion method. Therefore, VOS can be a valuable system for practitioners seeking real-time and accurate measurement of the sprint F-V profile.