title: Comparison between hand and electronic timing of 40-yd dash performance in college football players.
abstract: 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.
authors.affiliation: Human Performance Laboratory, Truman State University, Kirksville, Missouri, USA. jmayhew@truman.edu
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Mayhew
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Houser
authors.forename: Ben B
authors.initials: BB
authors.lastname: Briney
authors.forename: Tyler B
authors.initials: TB
authors.lastname: Williams
authors.forename: Fontaine C
authors.initials: FC
authors.lastname: Piper
authors.forename: William F
authors.initials: WF
authors.lastname: Brechue
mesh_terms: D000704:Analysis of Variance; D055615:Electrical Equipment and Supplies; D005538:Football / Q000502:physiology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012420:Running / Q000502:physiology*; D019876:Sports Equipment; D013995:Time; D055815:Young Adult