Does the old theory on a breakaway’s advantage still hold within today’s data-driven races?
I“The action on the road doesn’t always go by the numbers.”
f you’ve spent any time watching professional road cycling, you’ve probably seen Chapatte’s Law at work, maybe without even realizing it. The race or stage is nearing its finale. With 10 km to go and a breakaway up the road, the television commentators begin to hypothesize using Chapatte’s Law. This theory helps the commentators figure out if someone in the breakaway has a chance of winning or if the small group is doomed to get caught by the peloton behind.
The law comes from Robert Chapatte, who raced professionally from 1944 to 1954, and then went on to a decades-long career in radio and television broadcasting. His law states that the chasing peloton devours one minute of the breakaway’s advantage for every 10 km travelled. He was certain that a motivated breakaway could cross the line before the charging bunch, as long as they held a sixty second gap on the field at the 10-km mark. While Chapatte based his idea more on his racing experience than hard data, his instincts as an analyst are still valid, even within today’s era of data-devoted team managers and gigabytes of gps co-ordinates.
Kevin Field, head of performance strategy for Cycling Canada, is one of those data-driven directeurs sportifs. He’s worked with top Canadian athletes at world-class events, including Michael Woods for his bronze-medal ride at the 2018 road world championships. Field says pro teams are constantly looking at data to give them a competitive edge. The action on the road, however, doesn’t always go by the numbers. “It’s a game where 20 teams are playing at the same time,” he says. “You’ll never predict what they will or won’t do.”
On the road, Field and his teams use Chapatte’s Law to make strategic decisions in the heat of the moment. Having an idea of how much time it will take to pull back a breakaway is very important. Paired with accurate numbers, such as the speed of the peloton, the theory stays relevant.
Still, there are factors that can mess with Chapatte’s Law. Introduce a course with elevation, and the advantage of a large group is nullified with the slower speeds and less of an advantage coming from the peloton’s draft. The size of the breakaway and even weather can play major roles.
Andrew Randell, a former pro cyclist and national champion, used weather to his advantage at the Toronto Criterium in 2009. After establishing an early solo breakaway, it started to pour. “I remember thinking this is awesome,” recalls Randell, whose advantage would have been much harder to maintain if the chasers had dry roads. Randell also suggests Chapatte’s Law doesn’t take rider co-operation into account. “The break typically only wins if the peloton doesn’t do a good job of chasing them, whether they wait too long, or there’s arguments about who is going to do the work,” he says.
Field looks forward to the new ways teams will use data, but knows the action will always hinge on what he can’t control. “All it takes is one team deploying an unexpected attack to destabilize the whole race,” he says.