Resumen de Comparing Acceleration and Change of Direction Ability Between Backpedal and Cross-over Run Techniques for Use in American Football
Angelino Domenic, Thomas J.G McCabe, Jacob E. Earp
In American football, defensive backs guard receivers using either cross-over (CO) run or backpedal (BP) techniques, but the efficacy of these techniques is unknown. The purpose of this study was to compare linear acceleration (LA) and change of direction (CoD) ability when using CO and BP. Collegiate football defensive backs participated in LA (n = 13) and CoD (n = 7) testing. During LA, subjects performed CO, BP, and forward sprints with split times taken between 0-3 and 3-5 yd and ground reaction forces recorded 0 and 3 yd from the start. During CoD testing, subjects performed the CO or BP for 3 yd and then were given a cue to sprint to a gate 5 yd away in 1 of 4 directions (downfield, midfield, sideline, or upfield). In LA, CO was faster than BP between 0-3 yd ([DELTA] -0.20 +/- 0.02 seconds, p = 0.000) and 3-5 yd ([DELTA] -0.12 +/- 0.02 seconds, p = 0.000). At the start of the movement, CO demonstrated greater propulsive forces (p = 0.017). However, 3 yd from the start, CO demonstrated greater propulsive forces and reduced braking forces (p = 0.000 & 0.003). In CoD, CO was faster than BP when running in the downfield ([DELTA] 0.21 +/- 0.05 seconds, p = 0.044) and lateral directions ([DELTA] 0.21 +/- 0.08 seconds, p = 0.035), but similar in the upfield direction ([DELTA] 0.01 +/- 0.08, p = 0.986). Our results indicate that CO is superior to BP in LA, CoD ability, and movement efficiency and support the use of CO for defensive backs.
