Alterations of Neuromuscular Function after the World's Most Challenging Footrace

Author of Article
Jonas Saugy

Purpose –
Extreme endurance running has been gaining popularity recently. These mountain ultra-marathons consist of running or walking on trails and roads with positive and negative slopes over a long distance. These conditions provide the perfect opportunity to test the physiological changes that occur when the body is pushed beyond its limits. Studies have been conducted on similar races but never has one been done on one more than 50 hours. In races under 40 hours, neuromuscular fatigue, peripheral fatigue and knee extensors are all commonalities.
The race that was being researched was the 2011 Tor des Géants, where participants are subject to 80-150 hours of race time, 330 kilometers around the province of Val d'Aoste in Italy, and a total elevation change of 24000 meters (about 14 times the elevation of Mount Wilson). There were 471 starters and 301 finishers (64% completion). The distance is divided into seven parts and there were six aid-stations where sleeping is allowed. However, the participants do not have any required stops and can choose when they want to stop and where to keep going. Recovery time is still part of the race so the influence of pacing and sleep deprivation is crucial. This race is therefore different to other footraces of shorter distances where sleep management is of less importance.
Races like this also provide examiners to do a mid-race examination. The aim of the study is to investigate the effects of fatigue, muscle damage and inflammation in the most extreme (duration: 80–150 h) mountain ultra-marathons in the world. This was done by using data recorded before, during and after the event on both runners and control subjects. The research conducted during the course of this race can help scientists better understand fatigue in the human body.
Methods – Twenty-five male runners took part in the present study. Participants were tested three times: before, during, and approximately 30 minutes after the run. Of the 25 participants that started, 15 completed and 9 took part in all 3 testing sessions. All of the subjects were experienced in Events such as this and were well trained for the event.
The protocol for all tests go as follows: one test to measure the maximal voluntary contraction. This was done by measuring the subject’s neural fatigue using a series of electrical tests. Top force measured during the maximal voluntary contraction for each session was considered as the maximal voluntary contraction value. For measuring fatigue on knee extensors subjects were seated in an isometric ergometer comprised of a custom-built chair equipped with a strain gauge. The strain gauge measured the force that the knee gave without harming the subject. During the maximal voluntary contraction test, subjects were encouraged to give their maximum effort. Measuring plantar