UTMB 2019

Fatigability Compared Men and Women Induced According to the Distance Traveled on an Ultra-marathon in the Mountains

Trainee: Thibault Besson and Frederic Sabater (PhD Students)

Collaborators: 25 researchers and clinicians in St-Etienne, Chambéry and Lyon (LIBM)


Scientific summary

Extreme fatigue, as evidenced by acute physiological consequences of ultra-marathon running, is still under-investigated in women. Some studies have suggested that the amount of fatigue attributable to peripheral and central mechanisms varies between males and females; however, results are contradictory. Two studies from our lab conducted in 2009 and 2012 showed that a large part of fatigue induced by a mountain ultra-marathon could be attributed to central fatigue and that females exhibited less peripheral fatigue in the plantar flexors than males did after a 110-km ultra-trail-running race but the literature is quite scare on the topic. These findings need to be confirmed and it must also be determined whether or not this results is valid for shorter distances. Thus, the main purpose of the present project is to investigate whether sex differences in neuromuscular fatigue measured in isometric mode on knee extensors and plantar flexors as well as in dynamic mode depends on the distance (< 60 km vs > 100 km). The evolution of running biomechanics (including soft-tissue vibrations) and energy cost of running will also be compared between males and females in function of the race distance. In addition, hemorheological and inflammatory profiles will also be investigated in both men and women.


Key words: ultra-endurance, central and peripheral fatigue, haemorheology, muscle damage, force/velocity profile, vibration, running biomechanics, running economy.