Racehorse Speed Hasn’t Peaked Yet

Over the last 165 years, racehorses have gotten faster — especially when it comes to sprinting, researchers reported June 23 in Biology Letters. Their work also suggests that the increase in speed is ongoing. The continual uptick could be due to changes in riding styles or breeding techniques, Pallab Ghosh explains for the BBC.

Alastair Wilson, an evolutionary biologist at the University of Exeter, and Patrick Sharman, a grad student in Wilson’s lab, examined winning speed data from 616, 084 races across Great Britain between 1850 and 2012.

The improvement hasn’t been steady. The researchers found that speeds increased negligibly from 1910 to 1975, writes Ghosh. Between 1997 to 2012, winning times in short races (three quarters of a mile) had dropped by roughly 1.18 seconds. Given that sprints are often decided by the difference of fraction of a second, that’s a big jump. Speed increases in mid distance and long distance races didn’t see the same uptick.

The variation could be down to changes in riding technique, training or breeding. It’s unclear which. “My hunch is that we are seeing a genetic change, with breeders focusing on speed rather than endurance," Sharman speculated to Ghosh. "I don't believe that over the longer distances horses have reached their limit."

Still, the study contradicts a lot of previous work suggesting that horse race speeds had reached a plateau, and a general perception in the breeding industry that thoroughbred horses had reached their limit.

Horses may be increasing in speed, but that speed comes at a cost, as George Dvorsky points out for io9. Breeding horses purely for speed leaves them more susceptible to injury. Performance enhancing drugs — painkillers, steroids and other substances — and questionable training practices have also recently been linked to racehorse fatalities in the United States, as Dvorsky notes. Though performance-enhancing drugs are banned in Great Britain, some medications can be used in training.

So while horses could indeed get faster, people are starting to wonder at what cost. 

Helen Thompson | | READ MORE

Helen Thompson writes about science and culture for Smithsonian. She's previously written for NPR, National Geographic News, Nature and others.