Mindset can shape sports performance, but these effects can be difficult to detect empirically. We use data from high school sprinters to explore mindset effects on 100 m finishing times and find that headwinds hamper performance more than can be attributed to the physics of wind resistance alone. These (implied) psychological effects of wind on sprint times are stronger for girls than for boys. Having established the presence of mindset-based slack in physical performance, we then test whether sprint times changed in the wake of Matthew Boling’s record-breaking sprint in 2019 that, after going viral on social media, potentially boosted self-efficacy among high school sprinters. Using 2018 and 2019 high school track meets in California, we observe notable changes in average sprinter performance for certain types of athletes in specific wind conditions after Boling’s race that did not occur in the previous season. These results control for many observable variables, correct for multiple hypothesis testing, and use entropy balancing weights to ensure statistical comparability between the two years. We detect differences in this ‘Boling effect’ based on the predicted racial composition of teams and the predicted race of athletes, which is relevant given the racial angle of coverage of the record-setting run. We posit vicarious self-efficacy as a plausible explanation for these difference-in-differences patterns. Pronounced heterogeneity in these results demonstrates some of the complexities and nuances of mindset effects even in settings where performance is easily quantified. Subtle contextual and salience cues appear to mediate the impact of vicarious self-efficacy beliefs on performance.