Validation of the Run RocketTM for providing quantifiable resistance during resisted sprints

Resisted sprinting is purported to improve acceleration and maximum velocity sprinting performance, despite a lack of consensus on programming variables or its efficacy as a training methodology. The purpose of this study was to analyse whether Run RocketTM elicited similar reduction in velocity (Vdec), relative ground impulse and relative peak force to common sled towing masses. Thirteen recreationally active participants performed 10 m sprints at Run RocketTM levels of 10, 20 and 30, sled loads of 10%, 20% and 30% body mass, and 1 unresisted sprint. One-way repeated ANOVAs or Friedman Tests identified significant differences between conditions, and correlations analysed the magnitude of the relationships. Significance was set at p<0.05, effect size at 0.8. Run RocketTM elicited increasing Vdec, significantly greater than Vdec in any sled condition. The Run RocketTM induced significant increases in relative vertical and propulsive peak force in the first 2 steps of acceleration over sled tows, but not in relative braking peak force, relative propulsive, vertical or braking impulse. The results indicate that most Run RocketTM resistance levels are not equivalent to a given body mass % or Vdec, and may be too challenging to improve maximum velocity sprinting, yet not challenging enough to improve acceleration.