Is Chapatte’s theorem still relevant?, pro cycling news

Published on 04/26/2022 16:00

At a time of sprint trains and headsets, the life of a breakaway is getting tougher and tougher. So much so that their protective postulate, Chapatte’s theorem, seems on the verge of being empirically invalidated.

Last Monday, during the first stage of the Tour des Alpes, Geoffrey Bouchard (AG2R – Citroën) was hot, very hot, despite a large lead over the peloton 10 kilometers from the end of the route. Indeed, when he passed under the banner, the Dijonnais still had a 1’40 lead over the pack of favorites. On arrival, he only won for a handful of seconds, after having caused a lot of fears to his supporters.

On April 5, the Spaniard Ibon Ruiz (Kern Pharma) did not have the same fortune. Breaking out of the group of breakaways at the start of the final of the second stage of the Tour of the Basque Country, he also enjoyed a similar lead at the start of the last ten kilometers of the course. He was unfortunately taken back under the red flame, deprived of a first career victory by a hungry peloton.

On the first stage of the Tour des Alpes, Geoffrey Bouchard narrowly escaped the return of the peloton to claim the first victory of his careerOn the first stage of the Tour des Alpes, Geoffrey Bouchard narrowly escaped the return of the peloton to take the first victory of his career | © AG2R – Citroën Team / GettySports

Chapatte’s time theorem

These facts do not fail to recall the postulate of the famous « Chapate’s theorem », known to all cycling enthusiasts, whether young or old, that they do not miss a broadcast or only watch the end of stages. of the Tower. This is stated as follows: During a cycle race, if a rider breaking away alone finds himself one minute ahead of his immediate pursuers ten kilometers from the finish, he is considered to have a sufficient lead not to be caught before the arrival. « . Despite its formal tone, this statement is open to questioning, especially when looking at the context of its statement.

Robert ChapatteRobert Chapatte (1921 – 1997)

Robert Chapatte, after an honest career as a cyclist during the post-war period (1945-1954), experienced a successful conversion into audiovisual commentary, with exceptional longevity. Recruited by the RTF, he officiated first on the radio before switching to national television in 1960, thus receiving the privilege of participating in the hatching of cycling broadcasting. Victim of the purge following the events of May 1968, he was sidelined for a while on the small screen before returning to the window on Antenne 2 from 1976, where he remained until 1994. Pillar of the public channel, he rubbed shoulders with many famous consultants, such as Raphaël Géminiani (1981-1984), Jacques Anquetil (1985-1987), Raymond Poulidor (1988) or even Bernard Thévenet (1994). His career as a journalist was notably rewarded with the Henri Desgranges prize from the Académie des Sports in 1978.

From then on, the life of Robert Chapatte is symbolic of an era now gone, of a cycling regretted for its spectacle or mocked for its amateurism. This sport did not yet know Mario Cippolini, headsets or sprint trains. It still made it possible for the contenders for the yellow jersey to win flat stages or accumulate runners-up in the grouped finishes. He encouraged breakaways and swore by panache. It allowed staggering collections of bouquets (7 victories for Bernard Hinault on the Tour 79 for example). In short, he was quite different. These notable differences with the contemporary characteristics of the discipline thus tend to call into question the relevance of Chapatte’s theorem, as illustrated by the recent facts mentioned in the introduction.

Mario Cipollini, executioner of Chapatte's theorem?Mario Cipollini, executioner of Chapatte’s theorem?

Chapatte’s theorem weakened by mathematics

A mathematical approach is able to shed some light on the question. From the average speed of the escaped runner, a formula makes it easy to determine the average threshold at which the peloton must drive to catch the escapee before the finish. This brings us to the following consideration: if the breakaway is traveling at 50 km/h during the last 10 km, then the peloton must be traveling at a speed greater than 54.5 km/h to catch it before the line. Given the inertia of a peloton in the end of a professional race, this average speed is largely achievable. In the last edition of Paris-Roubaix alone, the first two hours of racing were covered at more than 48km/h, while the course stretched over 240 kilometres!

In addition, this average speed of 50 km / h already seems particularly difficult to maintain for a single man, worn out by several hours spent at the front of the race, frequently taking over from his breakaway partners. At the last time trial world championships, on a course without the slightest drop in altitude, the best riders in the world struggled to exceed the average speed of 52 km/h on their prototype specific to the exercise. Admittedly, the route measured 43 kilometers and not 10, but the efforts previously made by the breakaway to stand up to the peloton can be considered equivalent to the energy involved in such an event.

Thus, an average speed of 45 km/h seems more appropriate for a man who escaped alone. So all the peloton would have to do is drive at an average of 48.6 km/h to see him again, a threshold within reach of any organized sprint train. So imagine when there are about twenty of them competing against each other, as is the case in the Tour de France!

nullA breakaway on the Tour de France

And again, the scenario previously studied starts from the most favorable profile for breakaways: a flat course. Indeed, when the difficulties accumulate, the task becomes even more difficult for the unfortunate fugitive. A huge straight line, offering his vision in focus to the leaders of the peloton, also plays against him. And the wind also has a good place in the ranking of its worst enemies. Only a few things can help “save” it. They can come from the course, like a succession of tight turns (Mathieu Burgaudeau, 6and stage of Paris-Nice 2022), or intervene unexpectedly, following the example of vast and serious collective crashes (Luis Leon Sanchez, 9and stage of the 2011 Tour).

Chapatte denied by empiricism

In short, the empirical elements increasingly tend to contradict Chapatte’s theorem. Legions in the early 2000s, validation examples have effectively dried up over time. In 2009, the incredible Thomas Voeckler managed to keep the Tour peloton at bay even in the streets of Perpignan, to win the greatest victory of his career. Accompanied by 5 men, he was still 1 minute 20 ahead of the peloton 12 kilometers from the end of the stage.

But, already, on the occasion of the 7and stage of the Grande Boucle 2014, Greg Van Avermaet and Peter Sagan, who left in the middle of the day in strong, narrowly failed to play the bouquet in Nancy. At 20 terminals from the Lorraine city, they nevertheless had a 2-minute lead over the peloton. In 2017, one of the best riders in the world, Frenchman Rémi Cavagna, suffered the same fate at the end of the 4and stage of the Tour of Poland. A minute in advance 10 kilometers from the goal is not enough to raise the arms to Zabrze.

Thomas Voeckler's victory in Perpignan in 2009Thomas Voeckler’s victory in Perpignan in 2009

Consequently, the galloping modernization of cycling has undermined Robert Chapatte’s famous postulate. More and more frequently disavowed, it does not seem to resist the progression of sprint trains and the dictatorship of the earpieces. But perhaps he could still be suitable for judging the champions? Filippo Ganna, 10 kilometers from the finish, one minute ahead of the peloton, this is an interesting situation! Robert Chapatte wouldn’t miss a beat.

By Jean-Guillaume Langrognet

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