"Many a cyclist’s career has ended prematurely"

"Many a cyclist’s career has ended prematurely"

New test to diagnose vascular problems in cyclists

12-04-2023 · Research

One in five professional cyclists sooner or later end up facing symptoms of painful legs, cramps and loss of power. The cause is damage to the blood vessels. This cyclists’ complaint probably also affects many amateurs, but this is not clear.

Laurens ten Dam, Annemiek van Vleuten, Steven Kruijswijk, and Marianne Vos. They have all suffered badly from it and have been treated for it. Vos had an operation as recently as February. Ten days later, she was back cycling. Van Vleuten has had three operations, in 2009, in 2011 and in 2013. 

One in five professionals can expect blood vessel damage, showed a study in 2002 by researchers from the Máxima Medisch Centrum. Amateurs also suffer from it. Just how many, is unclear; of the 850 thousand cyclists and mountain bikers in the Netherlands, it is estimated that 75 thousand run an increased risk. The more and more intensely you cycle, the greater the chance. 

On Thursday, 13 April, human movement scientist Martijn van Hooff is graduating on this condition, which researchers refer to as FLIA (Flow Limitations in the Iliac Artery). A symposium is planned for a day later, with former ice-skating champion Hein Vergeer as honorary chairman. Many skaters have similar symptoms.

Left leg

The problem is with the bent position. From an anatomical point of view, the aorta splits into two around the stomach, the so-called pelvic arteries, each of which runs via the hip to a leg. Because of the bent position, every push on the pedals may cause the arteries to kink, just like a garden hose. 

This results in pain, cramps and loss of power. It is remarkable that this usually happens in the left leg, as was found in 70 per cent of the athletes. Van Hooff: “We don’t know exactly how this happens. In ice skaters, you could say that they continually make a left bend and that is why the left pelvic artery becomes trapped. But that theory doesn’t apply to cyclists."

Many athletes suffer in silence, says Van Hooff. "Amateurs, who suffer from more and more pain and whose performance drops, think that cycling is not for them, and maybe even miss out on a professional career because of this. There is awareness about the problem now in cycling teams and sports physicians are on the lookout, but GPs aren’t so aware of this condition. Such blood vessel problems are also difficult to diagnose, it is only possible with specialised tests."


In his PhD research, Van Hooff presents a new test. "Doctors often compare blood pressure in the arm, where there is no problem, to blood pressure in the ankles, where flow is possibly diminished resulting in lower blood pressure. The greater the difference, the greater the problem. But that test, which is applied worldwide, appears to be insufficiently reliable. As a result, half of the patients are not diagnosed as such."

In his PhD research, Van Hooff takes a closer look at a technique that goes by the abbreviation NIRS (near-infrared spectroscopy). An existing device, which until now was mainly used for research purposes, is taped to the thigh, and measures whether there is a reduced blood flow of the muscle during cycling. Or to be more precise: how long it takes before the oxygen supply in the muscle has recovered. “With this, I was able to trace three quarters of the patients."

Tour de France

There are three treatment centres worldwide, in London, Lyon and Veldhoven. That little town, which is a stone’s throw from Eindhoven has a sports department at the Máxima Medisch Centrum, where 120 to 150 patients are treated every year. 

Van Hooff says it starts by "operating on the bicycle". "By raising the handlebars just a fraction and pushing the saddle forward, you are sitting straighter on the bike, which can make a huge difference to amateurs. With professionals, an operation is often needed to repair the damage in the arteries caused by the blood flow having been cut off. This can be done by detaching the pelvic artery from the muscle tissue or, if the damage is more serious, through vascular reconstruction. The prospects are good."

Laurens ten Dam has had no complaints since his operation in 2004, he said in a podcast only last week. And Van Vleuten has won almost everything that could be won, including the Tour de France and the Giro d'Italia, since her surgery.

Hein Vergeer

There are also cyclists who don’t want to know, Van Hooff says. "A bad result takes hold in their heads, they say, and then they no longer cycle well. And yes, if the restriction is in an awkward place, an operation won’t help. Many cycling careers have ended prematurely due to this."

Why does it happen to one and not to another? “It appears to be genetic too. We once had a boy of fifteen come to the surgery, but that actually happens only rarely. Strongly developed thigh muscles can worsen the symptoms because they increase the kink in the arteries. 

It is not just cyclists who suffer from this, but also ice skaters. For former world champion Hein Vergeer, honorary chairperson at the symposium, the then still unfamiliar condition resulted in a dramatic end to his career. At the 1988 Olympic Games in Calgary, Vergeer was the favourite for first place, but apparently could not get up to speed. The audience, that first had him on a pedestal, now hissed at him. An inglorious end to a brilliant career. 

It was only fourteen years later that he discovered why his body had failed him. He read in a newspaper about blood vessel problems in cyclists.

Photo: Frans Peeters

Categories: news_top, Science
Tags: Hooff, flia, cycling

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