• Ut4M will take place from Thursday to Sunday around Grenoble, with a total of 12 events attracting 5,200 trail enthusiasts.

  • One of the specificities of this event is to focus precisely, since 2018, on the consequences of such trails (from 20 to 172 km depending on the chosen formula) on the health of runners.

  • This year, 40 participants are doing three MRIs in Grenoble, before and after the race, while wearing a blood glucose sensor throughout the week.

Vercors, Taillefer, Belledonne and Chartreuse.

These four massifs surrounding Grenoble will be as many stages, from Thursday to Sunday, to complete the 172 km (11,330 m of elevation gain) of the Ultra tour des 4 Massifs in its Challenge version.

After two years of absence, Ut4M is back with 5,200 registered for 12 events, but also with an astonishing initiative.

For the first time in the world, the teams of the Ut4M Grandeur nature laboratory are deploying significant resources to study the joint health of runners and the regulation of their blood sugar levels during a trail run.

Our dossier on the trail

This project was born in 2018, as part of a partnership with the HP2 laboratory of the University of Grenoble Alpes (Inserm) and the sports pathologies unit of the CHU Grenoble Alpes.

550 participants have responded over the past three years to a questionnaire from the trail-running research and innovation platform, both on their practice, their nutritional habits and their health, whether before starting a 20 km portion or trying the formidable Xtrem and its 172 chained terminals.

The ultra not so backbreaking for organizations?

"The objectives of this study are to improve the well-being of trail runners and their performance, to prevent injuries and certain health problems, and to reduce the percentage of dropouts", summarizes Samuel Vergès, doctor in physiology and director of research at the HP2 laboratory of the National Institute for Health and Medical Research (Inserm). With the help of 80 volunteers, he was able to carry out, three years ago, a precise study concerning the muscular fatigue of the participants, according to the chosen race distances.

"We were able to realize that the runners in the ultra format [172 km] were not four times more tired than those who chose a 40 km," he says.

They know how to regulate their tempo and their fatigue turns out to be more cerebral than muscular after such a long ordeal.

"A finding that captured the attention of Sébastien Accarier, organizer of this race which he founded in 2013 around Grenoble:" Discover that recovery times can be longer for runners who have opted for a "short" format. that for ultra-trail runners really surprised me.

This can be explained by the fact that they aim more at time-lapse performance ”.

"I am curious to learn more about myself"

With the help of a new panel of 40 runners, both over 40 and 172 km, the organization of Ut4M will put it back in this edition. "Such comprehensive studies are rare in the world," says Sébastien Accarier. We have the advantage of being close to medical structures, because many trail races take place deep in the mountains. There, the runners are mobilized, they want to help us while trying to better understand their potential axes of progression ”.

This is the case of the Grenoblois François Devaux (35), who will participate in his first Xtrem on Friday (172 km in one go), after having already completed the Ut4M Challenge (the same distance in four days).

“Participating in this program adds utility to my stupid challenges,” smiles this ultra-trail runner.

I am curious to learn more about myself through this scientific perspective.

"

"Maybe I will discover effects on my knee ..."

Thanks to the Ut4M, he performed an MRI of his right knee two weeks ago, and will do two more, first within two hours of the arrival of the Xtrem, then a month later. . “I run under the illusion of a healthy practice that does not harm my body,” says this computer systems architect. I try to have a neat stride but maybe I will discover effects on my knee… ”

The 2021 studies do not stop at the impact of trail running on the joint health of runners: François Devaux has been wearing a blood glucose sensor since Monday, to observe its regulation during the Ut4M.

"There too, I will know if I am working in the right way on an ultra, or if I put myself in the red when it comes to food," continues the person, medically monitored like a professional athlete, for the first time. of his life.

Samuel Vergès confirms:

These are quite unique research opportunities for these amateur runners.

Trail running is a discipline that is becoming more democratic and is now a real public health issue.

It is no longer seen as an extreme sport.

"

"Much less risk to your health than by staying on your sofa"

For the Inserm researcher, it is not obvious that the trail, with its substantial unevenness and stony or even chaotic paths, is more difficult for organizations than an urban marathon: "Stretching your stride on tar can be equally traumatic ”.

A clear observation is nevertheless required with this new study launched by Ut4M, to listen to Samuel Vergès: "You take much less risk for your health by doing trail running than by staying on your sofa accompanied by cigarettes and beers" .

Sorry to break the mood, fellow readers.

Sport

"They are downhill machines" ... Why does orienteering have "crazy athletes"?

Sport

Deconfinement: Why will trail running competitions finally regain their “flavor” this summer?

  • Health

  • Sport

  • Running

  • Grenoble

  • Mountain

  • Trail

  • Alps