Resumen de Comparison Between Hand and Electronic Timing of 40-yd Dash Performance in College Football Players
Jerry L. Mayhew, Jeremy J. Houser, Ben B. Briney, Tyler B. Williams, Fontaine C. Piper, William F. Brechue
The purpose of this study was to determine the difference between hand and electronic timing of 40-yd dashes in college football players. National Collegiate Athletic Association Division II players (n = 59) were measured during a 40-yd sprint by electronic timing and simultaneously by 7 experienced hand timers using digital stopwatches. Electronic times were initiated by lifting the hand from a switch mat and stopped by the torso passing through an infrared beam. Hand timers initiated timing on first movement of the player from a 3-point stance. To establish performance and timing reliabilities, 32 players completed a second trial. Interrater reliability for hand timing was intraclass correlation coefficient (ICC) = 0.987 (p < 0.001). Five of the 7 timers did not differ significantly (p > 0.05) in their timing. The maximum difference among the hand timers on any given trial was 0.19 ± 0.14 seconds, with a 95% confidence interval (CI) of -0.08 to 0.41 seconds. Hand timing (4.85 ± 0.28 seconds) was significantly faster (p < 0.001) than electronic timing (5.16 ± 0.28 seconds), producing an average difference of 0.31 ± 0.07 seconds (6.0 ± 1.3%) and a 95% CI on the average difference of -0.44 to -0.18 seconds. The correlation between electronic timing and hand timing was ICC = 0.985 (p < 0.001). Practically speaking, electronic timing produces the best measurement of 40-yd dash speed, and using the hand timing produces consistently but significantly faster times.
