12 research outputs found
Facteurs de la performance en course à pied : rôle de l'économie de course et de la fatigue
The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity.Les objectifs de cette thèse étaient d'étudier les déterminants de la performance de la course de trail, et d'évaluer les modifications d'économie de course (RE) après un exercice de course d'endurance prolongé. Nous avons dans un premier temps étudié les facteurs de la performance chez des coureurs sur route vs des coureurs de trail élite. Nos résultats ont montré que les coureurs de trail élite sont plus forts que les coureurs sur route, mais ont une moins bonne RE lorsqu'ils courent à plat. Dans la deuxième étude, nous avons évalué les facteurs permettant de prédire les performances en courses de trail de différentes distances, allant de 40 à 170 km. Nous avons constaté que la puissance maximale aérobie était un facteur déterminant de la performance pour les courses jusqu'à 100 km. La performance dans les courses plus courtes, jusqu'à environ 55 km, était également prédite par l'utilisation des lipides à faible vitesse, tandis que la performance sur les courses de 100 km était prédite par la force maximale des extenseurs du genou et le pourcentage de masse grasse. Les facteurs les plus importants pour la performance dans les courses de plus de 100 km sont encore débattus. Dans une 3ème étude, nous avons testé les effets de la distance des courses de trail sur RE. Nous avons constaté que RE se dégradait après des courses allant jusqu'à 55 km, mais pas lors des courses de 100 à 170 km. Enfin, dans une 4ème étude, nous avons testé les effets de deux modalités d'exercice différentes, le vélo et la course à pied, sur le coût de la locomotion, après 3 heures d'exercice à même intensité. Le coût de la locomotion a augmenté davantage après le cyclisme qu'après la course à pied, et le changement du coût de la locomotion en cyclisme était lié aux changements de cadence et à la perte des capacités de production de force
Facteurs de la performance en course à pied : rôle de l'économie de course et de la fatigue
The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity.Les objectifs de cette thèse étaient d'étudier les déterminants de la performance de la course de trail, et d'évaluer les modifications d'économie de course (RE) après un exercice de course d'endurance prolongé. Nous avons dans un premier temps étudié les facteurs de la performance chez des coureurs sur route vs des coureurs de trail élite. Nos résultats ont montré que les coureurs de trail élite sont plus forts que les coureurs sur route, mais ont une moins bonne RE lorsqu'ils courent à plat. Dans la deuxième étude, nous avons évalué les facteurs permettant de prédire les performances en courses de trail de différentes distances, allant de 40 à 170 km. Nous avons constaté que la puissance maximale aérobie était un facteur déterminant de la performance pour les courses jusqu'à 100 km. La performance dans les courses plus courtes, jusqu'à environ 55 km, était également prédite par l'utilisation des lipides à faible vitesse, tandis que la performance sur les courses de 100 km était prédite par la force maximale des extenseurs du genou et le pourcentage de masse grasse. Les facteurs les plus importants pour la performance dans les courses de plus de 100 km sont encore débattus. Dans une 3ème étude, nous avons testé les effets de la distance des courses de trail sur RE. Nous avons constaté que RE se dégradait après des courses allant jusqu'à 55 km, mais pas lors des courses de 100 à 170 km. Enfin, dans une 4ème étude, nous avons testé les effets de deux modalités d'exercice différentes, le vélo et la course à pied, sur le coût de la locomotion, après 3 heures d'exercice à même intensité. Le coût de la locomotion a augmenté davantage après le cyclisme qu'après la course à pied, et le changement du coût de la locomotion en cyclisme était lié aux changements de cadence et à la perte des capacités de production de force
Facteurs de la performance en course à pied : rôle de l'économie de course et de la fatigue
The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity.Les objectifs de cette thèse étaient d'étudier les déterminants de la performance de la course de trail, et d'évaluer les modifications d'économie de course (RE) après un exercice de course d'endurance prolongé. Nous avons dans un premier temps étudié les facteurs de la performance chez des coureurs sur route vs des coureurs de trail élite. Nos résultats ont montré que les coureurs de trail élite sont plus forts que les coureurs sur route, mais ont une moins bonne RE lorsqu'ils courent à plat. Dans la deuxième étude, nous avons évalué les facteurs permettant de prédire les performances en courses de trail de différentes distances, allant de 40 à 170 km. Nous avons constaté que la puissance maximale aérobie était un facteur déterminant de la performance pour les courses jusqu'à 100 km. La performance dans les courses plus courtes, jusqu'à environ 55 km, était également prédite par l'utilisation des lipides à faible vitesse, tandis que la performance sur les courses de 100 km était prédite par la force maximale des extenseurs du genou et le pourcentage de masse grasse. Les facteurs les plus importants pour la performance dans les courses de plus de 100 km sont encore débattus. Dans une 3ème étude, nous avons testé les effets de la distance des courses de trail sur RE. Nous avons constaté que RE se dégradait après des courses allant jusqu'à 55 km, mais pas lors des courses de 100 à 170 km. Enfin, dans une 4ème étude, nous avons testé les effets de deux modalités d'exercice différentes, le vélo et la course à pied, sur le coût de la locomotion, après 3 heures d'exercice à même intensité. Le coût de la locomotion a augmenté davantage après le cyclisme qu'après la course à pied, et le changement du coût de la locomotion en cyclisme était lié aux changements de cadence et à la perte des capacités de production de force
Facteurs de la performance en course à pied : rôle de l'économie de course et de la fatigue
Les objectifs de cette thèse étaient d'étudier les déterminants de la performance de la course de trail, et d'évaluer les modifications d'économie de course (RE) après un exercice de course d'endurance prolongé. Nous avons dans un premier temps étudié les facteurs de la performance chez des coureurs sur route vs des coureurs de trail élite. Nos résultats ont montré que les coureurs de trail élite sont plus forts que les coureurs sur route, mais ont une moins bonne RE lorsqu'ils courent à plat. Dans la deuxième étude, nous avons évalué les facteurs permettant de prédire les performances en courses de trail de différentes distances, allant de 40 à 170 km. Nous avons constaté que la puissance maximale aérobie était un facteur déterminant de la performance pour les courses jusqu'à 100 km. La performance dans les courses plus courtes, jusqu'à environ 55 km, était également prédite par l'utilisation des lipides à faible vitesse, tandis que la performance sur les courses de 100 km était prédite par la force maximale des extenseurs du genou et le pourcentage de masse grasse. Les facteurs les plus importants pour la performance dans les courses de plus de 100 km sont encore débattus. Dans une 3ème étude, nous avons testé les effets de la distance des courses de trail sur RE. Nous avons constaté que RE se dégradait après des courses allant jusqu'à 55 km, mais pas lors des courses de 100 à 170 km. Enfin, dans une 4ème étude, nous avons testé les effets de deux modalités d'exercice différentes, le vélo et la course à pied, sur le coût de la locomotion, après 3 heures d'exercice à même intensité. Le coût de la locomotion a augmenté davantage après le cyclisme qu'après la course à pied, et le changement du coût de la locomotion en cyclisme était lié aux changements de cadence et à la perte des capacités de production de force.The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity
Facteurs de la performance en course à pied : rôle de l'économie de course et de la fatigue
The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity.Les objectifs de cette thèse étaient d'étudier les déterminants de la performance de la course de trail, et d'évaluer les modifications d'économie de course (RE) après un exercice de course d'endurance prolongé. Nous avons dans un premier temps étudié les facteurs de la performance chez des coureurs sur route vs des coureurs de trail élite. Nos résultats ont montré que les coureurs de trail élite sont plus forts que les coureurs sur route, mais ont une moins bonne RE lorsqu'ils courent à plat. Dans la deuxième étude, nous avons évalué les facteurs permettant de prédire les performances en courses de trail de différentes distances, allant de 40 à 170 km. Nous avons constaté que la puissance maximale aérobie était un facteur déterminant de la performance pour les courses jusqu'à 100 km. La performance dans les courses plus courtes, jusqu'à environ 55 km, était également prédite par l'utilisation des lipides à faible vitesse, tandis que la performance sur les courses de 100 km était prédite par la force maximale des extenseurs du genou et le pourcentage de masse grasse. Les facteurs les plus importants pour la performance dans les courses de plus de 100 km sont encore débattus. Dans une 3ème étude, nous avons testé les effets de la distance des courses de trail sur RE. Nous avons constaté que RE se dégradait après des courses allant jusqu'à 55 km, mais pas lors des courses de 100 à 170 km. Enfin, dans une 4ème étude, nous avons testé les effets de deux modalités d'exercice différentes, le vélo et la course à pied, sur le coût de la locomotion, après 3 heures d'exercice à même intensité. Le coût de la locomotion a augmenté davantage après le cyclisme qu'après la course à pied, et le changement du coût de la locomotion en cyclisme était lié aux changements de cadence et à la perte des capacités de production de force
Age-related performance at the Ultra-Trail du Mont-Blanc
Some of the effects of aging and inactivity can be confounded. Master athletes are an interesting model to investigate human aging as they are free from the deleterious effects of inactivity. The aim of the present study was to analyze the number of male finishers and their performance across age at the Ultra-Trail du Mont-Blanc® (UTMB®, 170 km, 10 000 m of elevation gain) and two shorter races organized during the same event, Courmayeur-Champex-Chamonix (CCC®, 101 km, 6100 m) and Orsières-Champex-Chamonix (OCC, 55 km, 3500 m). Eighty percent of the finishers were aged between 23 and 49 years when considering the three races together. Top 10 average speed progressively decreased with age independently of the distance of the race. For every competition, average speed for the Top 10 decreased by 10% between 23–39 yr and 40–49 yr, then by 20% per decade. Future interventional studies should investigate the physiological factors (e.g. neuromuscular fatigue) associated with the age-related decline in ultra-trail running performance
Effect of ground technicity on cardio-respiratory and biomechanical parameters in uphill trail running
International audienceThe goal of this study was to analyse the effects of ground technicity on cardio-respiratory and biomechanical responses during uphill running. Ten experienced male trail-runners ran similar to 10.5 min at racing pace on two trails with different (high and low) a priori technicity levels. These two runs were replicated (same slope, velocity, and distance) indoor on a motor-driven treadmill. Oxygen uptake, minute ventilation (V?(E)), heart rate as well as step frequency and medio-lateral feet accelerations (i.e. objective indices of uneven terrain running patterns adjustments) were continuously measured throughout all sessions. Rating of perceived exertion (RPE) and perceived technicity were assessed at the end of each bout. Oxygen cost of running (O2Cr) (+10.5%; p < 0.001), V?(E) (+21%; p < 0.004) and the range and variability of feet medio-lateral accelerations (+116% and +134%, respectively; p < 0.001), were significantly greater when running on trail compared to the treadmill, regardless of the a priori technicity level. Despite perceived technicity being lower on treadmill (p < 0.001), RPE was not different between trail and treadmill runs (p < 0.68). It is concluded that running uphill on a trail vs. a treadmill significantly elevates both O2Cr and magnitude/variability of feet medio-lateral accelerations but no difference could be identified between trails of different a priori technicities. These results strengthen the need for trainers and race organisers to consider terrain technicity per se as a challenging cardio-respiratory and biomechanical component in uphill trail running
Degradation of energy cost with fatigue induced by trail running: effect of distance
International audiencePurposeThe effect of trail running competitions on cost of running (Cr) remains unclear and no study has directly examined the effect of distances in similar conditions on Cr. Accordingly, the aims of this study were to (i) assess the effect of trail running races of 40–170 km on Cr and (ii) to assess whether the incline at which Cr is measured influences changes in Cr.MethodsTwenty trail runners completed races of 100 km (LONG) on similar courses and environmental conditions. Oxygen uptake, respiratory exchange ratio, ventilation, and blood lactate were measured before and after the events on a treadmill with 0% (FLAT) and 15% incline (UH) and Cr was calculated.ResultsCr increased significantly after SHORT but not LONG races. There was no clear relationship between changes in Cr and changes in ventilation or blood lactate. There was a significant correlation (r = 0.75, p ConclusionThe distance of the trail running race, but not the slope at which it is measured, influence the changes in Cr with fatigue. The mechanism by which Cr increases only in SHORT is not related to increased cost of breathing
Performance Determinants in Trail-Running Races of Different Distances
International audiencePurpose: While the physiological determinants of road running have been widely studied, there is a lack of research in trail-running racing performance. The aim of our study was to determine the physiological predictors of trail-running performance in races of different distances in similar terrain and weather conditions. Methods: Seventy-five trail runners participating in one of the races of the Ultra-Trail du Mont-Blanc were recruited. Previous to the race, each runner was evaluated with (1) an incremental treadmill test to determine maximal oxygen uptake, ventilatory thresholds, cost of running, and substrate utilization; (2) a power–force–velocity profile on a cycle ergometer; (3) maximal voluntary contractions of the knee extensors and plantar flexors; and (4) anthropometric characteristics. Neuromuscular fatigue was evaluated after the races. Twenty-four runners finished a SHORT (145 km) race. Correlations and multiple linear regressions were used to find the determinants of performance in each race distance. Results: Performance in SHORT was explained by maximal oxygen uptake and lipid utilization at 10 km/h ( r 2 = .825, P Conclusions: Performance in trail running is mainly predicted by aerobic capacity, while lipid utilization also influences performance in races <60 km and performance in approximately 100 km is influenced by muscle strength and body composition
Impact of running an ultramarathon on neuromuscular fatigue: effects of sex and distance.
International audienceFew studies have assessed sex differences in neuromuscular fatigue after prolonged running. Compared to men, women exhibit less peripheral fatigue in plantar flexor muscles (PF) after running a 110-km-mountain-ultramathon [1]. The purpose of the present study was to further characterize sex differences by examining various running distances. Thirty-six runners completed the study: 18 men (36 ± 8 years, 72.5 ± 9.6 kg) and 18 women (36 ± 8 years, 59.1 ± 5.8 kg). Men and women were matched by relative performance (i.e. percent of winning time of their sex category). Participants completed various races of the Ultra-Trail du Mont-Blanc® ranging from 40 km with 2,300 m of positive elevation change to 170 km with 10,000 m of positive elevation change. One month before the race, participants visited the lab to be familiarized with electrical stimulation on both knee extensor (KE) and PF muscles. Neuromuscular function was tested before and after each race. The testing protocol consisted of a standardized warm-up followed by the assessment of maximal voluntary contractions (MVCs), maximal voluntary activation (superimposed 100 Hz doublet) and contractile properties (potentiated 100 Hz doublet, potentiated 10 Hz doublet and potentiated single twitch (Pt)). For analysis, participants were further subdivided into two groups of 18 runners by distance of race completed (SHORT < 100 km vs LONG ≥ 100 km). A factorial ANOVA with deficit (in percentage of PRE value) as a dependent factor and with sex and distance as between-subject factors was used for the analysis.MVC loss was greater after LONG than SHORT in both KE (p<0.05) and PF (p<0.01) and the decrease in Pt was significantly greater (p<0.05) in LONG compared to SHORT in KE, independent of sex. In PF, the decrease in MVC was greater (p<0.05) in men than women (-35 ± 11% vs -25 ± 13%, respectively), independent of the distance run. However, women exhibited a greater decrease in Pt compared to men in LONG (p<0.05) for PF. Neither sex nor distance effects were observed in maximal voluntary activation for either muscle group.The greater muscle strength loss in LONG compared to SHORT fits the previously reported relationship between strength loss and race duration (2). Surprisingly, the present study displayed greater peripheral fatigue in women compared to men after LONG races. However, women lost less muscle strength in PF than men, suggesting that they were globally more resistant to fatigue in plantar flexor muscles.[1] Temesi J et al. (2015). Med Sci Sports Exerc, 47: 1372-82.[2] Millet GY. (2011). Sports Med, 41(6): 489-506