Quantification of velocity decrement and kinetic profile during 10 metre resisted sprinting using the Run RocketTM

The Run RocketTM is used to improve acceleration and maximum velocity sprinting performance. However, no empirical data exist to support its efficacy. Accordingly, this study aimed to examine how incremental Run RocketTM loads effect sprint velocity (Vdec), relative ground impulse and relative peak force. Fourteen recreationally active (13 male, 1 female) participants performed 10 m sprints at three Run RocketTM arbitrary (AU) resistance levels (10, 20 and 30 AU and unresisted sprints). One-way repeated measures ANOVA, and Cohen’s d effect sizes identified significant and meaningful differences between conditions. Run RocketTM induced significant, large (d= >4.50) Vdec across all conditions. First and second step ground contact times showed large effects (d= >2.50) when comparing unresisted sprinting to all Run Run RocketTM conditions. Concomitant moderate increases were observed for first and second step relative horizontal propulsive impulses, while first and second step relative horizontal propulsive forces showed no effect, suggesting Vdec was attributable to increases in ground contact time during resisted sprinting using the Run RocketTM in all conditions. The results indicate most Run RocketTM resistance levels might be too challenging to improve maximum velocity sprinting, yet not challenging enough to improve acceleration. Therefore, lighter Run RocketTM resistances may be preferential.