Under extreme conditions, the human body is pushed to its limits. In order to better define the physiological mechanisms involved, researchers followed athletes during a very special competition: the Tor des Géants. During the 2011 edition of this 330km ultramarathon, they observed that the runners’ neuromuscular and biological functions were preserved, compared to races over shorter distances.
This article is a translation of "Courses en conditions extrêmes : le tout est de savoir se ménager..." by Timothée Froelich.
Nothing compares to the conditions of a mountain ultramarathon to study the human body’s physiological reactions to extreme strain! An ultramarathon is a running race over a distance longer than 42.195 km, the length of a traditional marathon. Add to that steep slopes and gravel paths and you get ultra-trails such as the Tor des Géants or the Ultra-Trail du Mont-Blanc (UTMB). The latter is a race over approximately 170 km (100 miles) with 9,600 m of elevation gain. As for the Tor des Géants, its route covers a total of 330 mountainous kilometers in the Aosta Valley, Italy, with a vertical gain of 24,000 m. By studying the reactions of the athletes during these two events, the researchers could compare their effects on the body.
The ultra-trail, a case study of exercise physiology
Professor Grégoire Millet, from the Sport Science Institute of the University of Lausanne, Switzerland, has developed a great interest in these races. They provide a wealth of information for his studies on altitude training and ultra-endurance. With his brother Guillaume Millet, he showed in a publication available on MyScienceWork that the ultra-marathon could be used as a case study of exercise physiology.
In 2011, Guillaume Millet revealed in the journal Sports Medicine that after 30 to 36 hours of running during the UTMB, the maximal muscle contraction plateaued after a 40% decrease. Grégoire Millet wanted to find out more about the effects of a longer race that notably requires planning breaks to sleep. He followed 25 sportsmen, including himself, during the Tor des Géants. He was able study the human body’s physiological responses thanks to different tests carried out before, during and after the race. The results were recently published in a PLOS One article with Jonas Saugy as first author.
The Tor des Géants: not so inaccessible…
The researchers were surprised to discover that the Tor des Géants caused a decrease of only 25% to 30% in maximal voluntary strength generated by muscles. By comparison, a decrease of 40% was observed during the UTMB. “The determining factor is the combination of the intensity of the exercise and the distance”, states Grégoire Millet.
The sequences of rest breaks can partly explain why neuromuscular fatigue is less significant in a longer race. It is also relevant that the feeling of general fatigue is not necessarily very high at the finish line, but each runner has most likely experienced extreme fatigue at certain points during the race. “Between a 170 km race and a 330 km race, there is not only an increase in distance; the way of running and the final fatigue change as well. Even in such extreme trials, the human body is able to manage and let the athlete finish in a fairly good state”, concludes Grégoire.
Strategic preparation for the Tor des Géants
After his participation in 2011 as a guinea pig for the study on neuromuscular fatigue, in 2012 Grégoire Millet ran using the knowledge that he teaches and the results of his team’s research at the University of Lausanne. In particular, his work concerns the running pace and the schedule of rest breaks. This helped him establish a particularly well-developed strategy for winning. For instance, he slept at the bottom of a mountain pass rather than at the top, because the energy gain is far more profitable. Resting before ascending lets one climb faster, whereas it has no impact when descending.
Three key areas were determined. First, to be effective, you have to save energy, that is, expend less energy per unit of distance. Then, you have to keep a high rate-of-climb, instead of trying to go down as fast as possible. This parameter is also significant for the last strategic point: minimizing injuries. To do so, you must regularly change shoes and socks, and minimize joint load by remaining as light as possible. To get ready for the race, Grégoire Millet lost 44 pounds.
He finished second in the 2012 edition, in only 78 hours, and showed that “sport science is not only about theory, it can also come in handy”.
To find out more:
Professor Guillaume Millet’s study during the UTMB : Can Neuromuscular Fatigue Explain Running Strategies and Performance in Ultra-Marathons?, Sports Medicine, June 2011, Vol. 41, p 489-506
Running 200 miles ultramarathon is healthier, The Times Of India, 2013