Purpose. Many strength and conditioning professionals propose that postactivation potentiation (PAP) warm-ups enhance power performance although there are few studies conducted in this regard on sprinting. Therefore, the purpose of this study was to determine the effects of a PAP warm-up on sprint performance. Methods. Twenty-four men and women completed a 40-yard (yd) sprint pretest on four nonconsecutive days followed by a PAP warm-up that included a sled resistance sprint at either 0%, 10%, 20%, or 30% of their body mass and concluded with a 40-yd dash posttest. Each resistance sprint was recorded for kinematic analysis. Results. A 2 × 2 × 4 factorial mixed ANOVA revealed a statistically significant difference between sexes in 40-yd dash times (p < 0.001). A significant main effect was found in pre- and post-40-yd dash measures regardless of sex (p < 0.001). The results indicated no significant differences in the post-40-yd dash times between sled loads and the load by time interaction. The participants’ 40-yd dash times improved 1.2% on average after the 10% load. Improvements in dash time for the 0%, 20%, and 30% loads were greater than 2%. Sprint kinematics analysis demonstrated statistically significant differences between lighter and heavier loads. Conclusions. Regardless of the significant disruptions in sprint mechanics, there appears to be a potential for heavier sled resistances to affect acute improvements in 40-yd sprint performance. However, it is unclear whether heavier sleds loads may provide greater benefit than warming up with 0% resistance.