Analyzing 30 years of Kentucky Derby pace fractions

Once upon a time, the Kentucky Derby (G1) was a race in which any running style could succeed. Front-runners, pressers, stalkers, and deep closers alike prevailed with regularlity.

But times have changed. While deep closers still occasionally win the Kentucky Derby, recent years have seen speed horses dominate the 1 1/4-mile Run for the Roses. Does this shift represent a statistical anomaly or a new normal? Handicappers are scratching their heads searching for the answer.

Between 1993 and 2013, 12 horses won the Derby by racing in the front half of the pack while nine winners emerged from the back half of the field. War Emblem (2002) and Go for Gin (1994) prevailed in gate-to-wire fashion, Mine That Bird (2009) closed from dead last, and the others came from everywhere in between. Generally speaking, the pace fractions determined the most effective running style for any given year; Derbys featuring a sub-:46 half-mile fraction were more likely to produce winners rallying from eight lengths or more off the lead.

Yet recent Kentucky Derbys have unfolded in dramatically different fashion. Between 2014 and 2022, eight of the nine horses to cross the finish line in first place employed pacesetting, pressing, or stalking tactics. In each of those eight cases, the horse who crossed the finish line first was positioned no farther back than third place at any call, even when the pace was fast. Just check out Justify (2018) and Nyquist (2016), who showed no ill effects from chasing sub-:46 half-miles.

Why has the complexion of the Kentucky Derby changed so sharply? A popular theory holds that the introduction of the Road to the Kentucky Derby qualifying system in 2013 reduced the intensity of the pace by removing pure sprinters from the Derby field, giving an advantage to speed horses.

But this theory doesn’t hold up under scrutiny. Analyzing the last 30 years of Derby pace fractions, broken down in 10-year increments, shows that the quarter-mile, half-mile, and six-furlong fractions have grown faster since the introduction of the Road to the Kentucky Derby. Furthermore, the 2013 Derby—the first held under the new qualifying system—produced some of the fastest fractions in Derby history. And in 2022, the Kentucky Derby produced an opening quarter-mile in :21.78, the fastest ever.

In contrast, the run down the Derby homestretch has gotten slower in recent decades. The average final quarter-mile time was :25.53 from 1993-2002, but it slowed to :25.69 from 2003-2012 and plummeted to :26.00 from 2013-2022. (It should be noted the 1993-2002 sample contains only one wet-track Derby versus three from 2003-2012 and four from 2013-2022.)

Taking all of this together, it’s evident recent Kentucky Derbys have been unfolding in increasingly fast early/slow late fashion. Normally such a race shape is favorable to late runners, so the fact speed horses have been dominating is surprising.

It almost seems as though modern Derby contenders lack the stamina to truly thrive over the testing 1 1/4-mile distance. This could explain why the fast early/slow late fractions have been ironically favoring speed horses. If everyone is out of gas by the top of the stretch, then no one—not even the deepest closer—has the energy to produce a genuinely strong finish. Thus, horses positioned near the lead turning for home have an advantage.

Handicappers can argue all day why today’s Derby horses seem to struggle over 1 1/4 miles. Perhaps an emphasis on breeding for speed made an impact. Perhaps changes in training and racing regimens are responsible. Perhaps the Churchill Downs main track has grown deeper and more tiring, though the increasingly quick early fractions disagree with that argument.

In any case, the Kentucky Derby has changed to more closely reflect the tendencies of U.S. dirt racing in general. Speed is king on the main track, and barring another sudden change in Derby dynamics—not impossible in the historic yet ever-shifting sport of Thoroughbred racing—horses with tactical speed should continue to excel in the Run for the Roses.