Exaggerated flexion of a horse's poll and neck, although surely practiced in the past, became popularized (so to speak) in dressage in the 1980s when Nicole Uphoff of Germany used it as a training technique with her horse, Rembrandt. Riding the notoriously spooky gelding in what was then referred to as a "low, deep, and round" outline helped Uphoff to manage the horse, according to much of what was published at the time. Switching to a competition-acceptable outline or "frame," Uphoff piloted Rembrandt to back-to-back team and individual dressage gold medals at the 1988 Seoul Olympic Games and the 1992 Barcelona Olympics.
Uphoff's methods, not surprisingly, were emulated by other dressage riders, both professional and amateur. The German champion Isabell Werth, who won a string of team and individual Olympic gold and silver medals from 1992 through 2000, reportedly schooled some mounts low, deep, and round. The rider whose name has become most closely associated with the method is the Dutch star Anky van Grunsven, Werth's chief rival in the 1900s and 2000s and who herself racked up a running string of team and individual dressage medals, ending with individual golds aboard Salinero in Athens 2004 and Hong Kong 2008.
As the years progressed, some dressage enthusiasts became increasingly alarmed by what they viewed as an improper training technique that violated the principles of classical horsemanship. Allegedly less egregious when used by knowledgeable riders, "rollkur," as detractors dubbed it, could be downright harmful to horses when used by inexperienced riders, they asserted. In the mid-2000s the German veterinarian Dr. Gerd Heuschmann, working with German Olympic dressage champion Klaus Balkenhol, created headlines when they publicized the findings of Heuschmann's anatomical and biomechanical studies of hyperflexion. Heuschmann said that hyperflexion not only fails to develop the proper musculature for upper-level dressage, but the exaggerated flexion can also restrict the horse's airway. Heuschmann published a book, Tug of War: Classical Versus "Modern" Dressage, detailing his findings and arguing against the practice of hyperflexion.
Before long, rollkur had gone from innovative training method to dressage dirty word. The change in public sentiment happened to coincide with the rise of the Internet and the social-media age, and as a result the practice and the practitioners found images of themselves posted online as dressage spectators and media alike snapped photos and shot video of riders apparently using hyperflexion in schooling and in competition warm-up arenas. Meanwhile, Heuschmann, Balkenhol, and other like-minded people founded an organization, Xenophon, to bring attention to what they said was a harmful practice. And the dressage community began to press for change.
Sometimes change doesn't happen until it's legislated. In 2010, the International Equestrian Federation (FEI) added a section, Annex XIII, to the FEI Stewards Manual for dressage. The addendum includes illustrations of three "permitted stretches," all variations on the low-deep-round or long-and-low outlines. Stewards at CDIs (FEI-sanctioned dressage competitions) are now instructed to intervene if they see riders performing "deliberate extreme flexions of the neck" for more than "very short periods." Stewards are also charged with intervening if they see "neck stretching through forced or aggressive riding" or "a rider deliberately maintaining a sustained fixed head and neck carriage longer than approximately ten minutes," among others.
Some dressage enthusiasts remain convinced that rollkur still occurs. During the dressage competition at the 2012 London Olympic Games, some photos circulated on the Internet, appearing to show Swedish competitor Patrik Kittel on Scandic riding in a hyperflexed position. Online forums and the FEI's Facebook page, among others, were barraged with expressions of outrage and accusations that the FEI was failing to enforce Annex XIII of the Stewards Manual. A statement by the FEI indicating that it considers a photo a "moment in time" and asserting that the Olympic horses were in fact properly supervised did little to calm the storm.
I asked FEI 4* dressage judge Stephen Clarke of Great Britain, who was a member of the seven-judge panel at the London Games, if he thinks there is any fire behind all the smoke. He stated emphatically that the Olympic training and warm-up arenas are so well policed by the stewards that it is not possible for a competitor to have violated the rules on stretching and hyperflexion and gotten away with it.
Inasmuch as I was there, some people have asked me for my opinion. Although I was unable to watch every training session, I did observe some of the Dutch dressage riders schooling and saw no evidence of rollkur. At an Olympic Games, you can't just be a railbird at the competition warm-up arena the way you can at an ordinary show. I couldn't get close enough to the warm-up to be able offer any sort of educated assessment, but I can tell you that the area was not hidden away and there were plenty of stewards on hand.
Of course, I can't tell you what riders do at home, when the stewards, the spectators, and the media aren't around. But it is true that the judges in London marked down horses whose necks became short and tight and whose profiles tended to duck behind the vertical, as it's called. According to Stephen Clarke, such horses lost anywhere from 1 to 2 points per movement, depending on the sum total of factors for the movement in question. And it's also true that the dressage gold medalists in London did not persistently get short in the necks and go behind the vertical.
For education's sake, I'd like to end this discussion with three photos I took in London. All are of Adelinde Cornelissen and Parzival of the Netherlands, who won a team bronze medal and the individual silver. All were taken just before or during their team Grand Prix test. The first shows Adelinde overflexing Parzival before entering the arena. This position is what would be termed rollkur. It is not pretty to look at, and I am not defending the rider, but I can tell you that she held that position very briefly--a stride or two.
The second photo shows Parzival during an unfortunate moment in passage. The FEI dressage rules specify that the horse's poll should be its highest point, and its profile should be on the vertical or slightly in front of the vertical. Parzival is tight in his neck and behind the vertical, and a point on his neck slightly behind his poll appears to have become the highest point as a result. I've added a red line and an arrow to the photo to help show this. These are undesirable factors for which Adelinde was marked down; however, this position is not rollkur.
The final photo, of Parzival in piaffe, is much better. Even in this highly collected movement, the horse's neck does not appear cramped. His poll is the highest point, and his nose is slightly in front of the vertical.
Although the rollkur controversy is not over, I suspect that it is on its way out as a riding technique. There is enough outcry and watchdog efforts on the subject that I doubt the FEI will look the other way when it comes to stewarding. Ultimately, competitors tend to do what scores well with the judges. The judging in London makes me optimistic that correct--yes, classical--training and riding are being rewarded.