Ecole Nationale des Sports de Montagne

Cauville-sur-Mer, France

Ecole Nationale des Sports de Montagne

Cauville-sur-Mer, France
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Pichon A.P.,University of Poitiers | Pichon A.P.,University of Paris 13 | Connes P.,Institut Universitaire de France | Connes P.,University Claude Bernard Lyon 1 | And 2 more authors.
Clinical hemorheology and microcirculation | Year: 2016

The aim of the present study was to investigate the effects of manipulating hematocrit by different methods (acute exercise, training or isovolumic hemodilution) on blood viscosity in high-level aerobic endurance athletes. We hypothesized than increasing hematocrit does not always cause a rise in blood viscosity.Sixteen endurance athletes underwent maximal exercise before and after 4 weeks of training with (LHTL; n = 10) or without (placebo; n = 6) Live High-Train Low modalities. Total hemoglobin mass was measured before and after training by a carbon monoxide rebreathing technique. After training, subjects performed two maximal exercise bouts separated by isovolumic hemodilution (phlebotomy and/or plasma volume expander) to readjust red blood cell volume and plasma volume to baseline values. Blood samples were obtained before and after exercise to assess hematocrit and blood and plasma viscosity.Training session (LHTL and placebo) increased hematocrit (Hct) in all subjects but without any significant change in blood viscosity. The decrease in plasma viscosity in all groups may explain this result. Isovolumic hemodilution caused a drop of Hct without any significant change in blood viscosity at rest. Maximal exercise increased Hct, blood and plasma viscosities in both groups, regardless of isovolumic hemodilution. However, peak hemorheological values after exercise were lower after isovolumic hemodilution.In conclusion, while acute increase in Hct during exercise caused an increase of blood viscosity, the chronic increase of Hct induced by training session did not result in a rise in blood viscosity. The lowering of plasma viscosity during training may compensate for the increase of Hct, hence limiting its impact on blood viscosity.


Bonne T.C.,Copenhagen University | Doucende G.,University of Perpignan | Fluck D.,University of Zürich | Jacobs R.A.,University of Zürich | And 5 more authors.
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2014

With this study we tested the hypothesis that 6 wk of endurance training increases maximal cardiac output (Q̇max) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (V̇O2max 47 ± 5 ml·min-1·kg-1) underwent supervised training (60 min; 4 times weekly at 65% V̇O2max for 6 wk), and Q̇max was determined by inert gas rebreathing during cycle ergometer exercise before and after the training period. After the training period, blood volume (determined in duplicates by CO rebreathing) was reestablished to pretraining values by phlebotomy and Q̇max was quantified again. Resting echography revealed no structural heart adaptations as a consequence of the training intervention. After the training period, plasma volume (PV), red blood cell volume (RBCV), and BV increased (P < 0.05) by 147 ± 168 (5 ± 5%), 235 ± 64 (10 ± 3%), and 382 ± 204 ml (7 ± 4%), respectively. V̇O2max was augmented (P < 0.05) by 10 ± 7% after the training period and decreased (P < 0.05) by 8 ± 7% with phlebotomy. Concomitantly, Q̇max was increased (P < 0.05) from 18.9 ± 2.1 to 20.4 ± 2.3 l/min (9 ± 6%) as a consequence of the training intervention, and after normalization of BV by phlebotomy Q̇max returned to pretraining values (18.1 ± 2.5 l/min; 12 ± 5% reversal). Thus the exercise training-induced increase in BV is the main mechanism increasing Q̇max after 6 wk of endurance training in previously untrained subjects.


Mazzarino M.,Sportiva | Cesarei L.,Sportiva | de la Torre X.,Sportiva | Fiacco I.,Sportiva | And 4 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2016

This work presents an analytical method for the simultaneous analysis in human urine of 38 pharmacologically active compounds (19 benzodiazepine-like substances, 7 selective serotonin reuptake inhibitors, 4 azole antifungal drugs, 5 inhibitors of the phosphodiesterases type 4 and 3 inhibitors of the phosphodiesterase type 5) by liquid-chromatography coupled with tandem mass spectrometry. The above substances classes include both the most common "non banned" drugs used by the athletes (based on the information reported on the "doping control form") and those drugs who are suspected to be performance enhancing and/or act as masking agents in particular conditions. The chromatographic separation was performed by a reverse-phase octadecyl column using as mobile phases acetonitrile and ultra-purified water, both with 0.1% formic acid. The detection was carried out using a triple quadrupole mass spectrometric analyser, positive electro-spray as ionization source and selected reaction monitoring as acquisition mode. Sample pre-treatment consisted in an enzymatic hydrolysis followed by a liquid-liquid extraction in neutral field using tert-butyl methyl-ether. The analytical procedure, once developed, was validated in terms of sensitivity (lower limits of detection in the range of 1-50ngmL-1), specificity (no interferences were detected at the retention time of all the analytes under investigation), recovery (≥60% with a satisfactory repeatability, CV % lower than 10), matrix effect (lower than 30%) and reproducibility of retention times (CV% lower than 0.1) and of relative abundances (CV% lower than 15). The performance and the applicability of the method was evaluated by analyzing real samples containing benzodiazepines (alprazolam, diazepam, zolpidem or zoplicone) or inhibitors of the phosphodiesterases type 5 (sildenafil or vardenafil) and samples obtained incubating two of the phosphodiesterases type 4 studied (cilomilast or roflumilast) with pooled human liver microsomes. All the parent compounds, together with their main phase I metabolites, were clearly detected using the analytical procedures here developed. © 2015 Elsevier B.V.


PubMed | University Grenoble Alpes, Grenoble University Hospital Center, Sportiva, Agence Francaise de Lutte contre le Dopage and Ecole Nationale des Sports de Montagne
Type: Journal Article | Journal: PloS one | Year: 2016

Mont Blanc, the summit of Western Europe, is a popular but demanding high-altitude ascent. Drug use is thought to be widespread among climbers attempting this summit, not only to prevent altitude illnesses, but also to boost physical and/or psychological capacities. This practice may be unsafe in this remote alpine environment. However, robust data on medication during the ascent of Mont Blanc are lacking. Individual urine samples from male climbers using urinals in mountain refuges on access routes to Mont Blanc (Goter and Cosmiques mountain huts) were blindly and anonymously collected using a hidden automatic sampler. Urine samples were screened for a wide range of drugs, including diuretics, glucocorticoids, stimulants, hypnotics and phosphodiesterase 5 (PDE-5) inhibitors. Out of 430 samples analyzed from both huts, 35.8% contained at least one drug. Diuretics (22.7%) and hypnotics (12.9%) were the most frequently detected drugs, while glucocorticoids (3.5%) and stimulants (3.1%) were less commonly detected. None of the samples contained PDE-5 inhibitors. Two substances were predominant: the diuretic acetazolamide (20.6%) and the hypnotic zolpidem (8.4%). Thirty three samples were found positive for at least two substances, the most frequent combination being acetazolamide and a hypnotic (2.1%). Based on a novel sampling technique, we demonstrate that about one third of the urine samples collected from a random sample of male climbers contained one or several drugs, suggesting frequent drug use amongst climbers ascending Mont Blanc. Our data suggest that medication primarily aims at mitigating the symptoms of altitude illnesses, rather than enhancing performance. In this hazardous environment, the relatively high prevalence of hypnotics must be highlighted, since these molecules may alter vigilance.


Lundby C.,University of Zürich | Robach P.,Ecole Nationale des Sports de Montagne
Experimental Physiology | Year: 2016

What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society


Robach P.,Ecole Nationale des Sports de Montagne | Bonne T.,Copenhagen University | Fluck D.,University of Zürich | Burgi S.,University of Zürich | And 4 more authors.
Medicine and Science in Sports and Exercise | Year: 2014

Purpose: The effects of hypoxic training on exercise performance remain controversial. Here, we tested the hypotheses that i) hypoxic training possesses ergogenic effects at sea level and altitude and ii) the benefits are primarily mediated by improved mitochondrial function of the skeletal muscle. Methods: We determined aerobic performance (incremental test to exhaustion and time trial for a set amount of work) in moderately trained subjects undergoing 6 wk of endurance training (3-4 times per week, 60 min per session) in normoxia (placebo, n = 8) or normobaric hypoxia (FIO2 = 0.15, n = 9) using a double-blind and randomized design. Exercise tests were performed in normoxia and acute hypoxia (FIO2 = 0.15). Skeletal muscle mitochondrial respiratory capacities and electron coupling efficiencies were measured via high-resolution respirometry. Total hemoglobin mass was assessed by carbon monoxide rebreathing. Results: Skeletal muscle respiratory capacity was not altered by training or hypoxia; however, electron coupling control respective to fat oxidation slightly diminished with hypoxic training. Hypoxic training did increase total hemoglobin mass more than the placebo (8.4% vs 3.3%, P = 0.02). In normoxia, hypoxic training had no additive effect on maximal measures of oxygen uptake or time trial performance. In acute hypoxia, hypoxic training conferred no advantage on maximal oxygen uptake but tended to enhance time trial performance more than normoxic training (52% vs 32%, P = 0.09). Conclusions: Our data suggest that, in moderately trained subjects, 6 wk of hypoxic training possesses no ergogenic effect at sea level. It is not excluded that hypoxic training might facilitate endurance capacity at moderate altitude; however, this issue is still open and needs to be further examined. Copyright © 2014 by the American College of Sports Medicine.


Lundby C.,University of Zürich | Lundby C.,Gothenburg University | Robach P.,Ecole Nationale des Sports de Montagne
Physiology | Year: 2015

Our objective is to highlight some key physiological determinants of endurance exercise performance and to discuss how these can be further improved. V˙O2max remains remarkably stable throughout an athletic career. By contrast, exercise economy, lactate threshold, and critical power may be improved in world-class athletes by specific exercise training regimes and/or with more years of training. © 2015 Int. Union Physiol. Sci./Am. Physiol. Soc.


Jacobs R.A.,University of Zürich | Jacobs R.A.,Center for Integrative Human Physiology | Rasmussen P.,Center for Integrative Human Physiology | Rasmussen P.,University of Zürich | And 14 more authors.
Journal of Applied Physiology | Year: 2011

Human endurance performance can be predicted from maximal oxygen consumption (VO 2max), lactate threshold, and exercise efficiency. These physiological parameters, however, are not wholly exclusive from one another, and their interplay is complex. Accordingly, we sought to identify more specific measurements explaining the range of performance among athletes. Out of 150 separate variables we identified 10 principal factors responsible for hematological, cardiovascular, respiratory, musculoskeletal, and neurological variation in 16 highly trained cyclists. These principal factors were then correlated with a 26-km time trial and test of maximal incremental power output. Average power output during the 26-km time trial was attributed to, in order of importance, oxidative phosphorylation capacity of the vastus lateralis muscle (P = 0.0005), steady-state submaximal blood lactate concentrations (P = 0.0017), and maximal leg oxygenation (sO 2LEG) (P = 0.0295), accounting for 78% of the variation in time trial performance. Variability in maximal power output, on the other hand, was attributed to total body hemoglobin mass (Hb mass; P = 0.0038), VO2max (P = 0.0213), and sO 2LEG (P = 0.0463). In conclusion, 1) skeletal muscle oxidative capacity is the primary predictor of time trial performance in highly trained cyclists; 2) the strongest predictor for maximal incremental power output is Hb mass; and 3) overall exercise performance (time trial performance + maximal incremental power output) correlates most strongly to measures regarding the capability for oxygen transport, highVO2max and Hb mass, in addition to measures of oxygen utilization, maximal oxidative phosphorylation, and electron transport system capacities in the skeletal muscle. Copyright © 2011 the American Physiological Society.


PubMed | University of Poitiers, Institut Universitaire de France and Ecole Nationale des Sports de Montagne
Type: Journal Article | Journal: Clinical hemorheology and microcirculation | Year: 2016

The aim of the present study was to investigate the effects of manipulating hematocrit by different methods (acute exercise, training or isovolumic hemodilution) on blood viscosity in high-level aerobic endurance athletes. We hypothesized than increasing hematocrit does not always cause a rise in blood viscosity.Sixteen endurance athletes underwent maximal exercise before and after 4 weeks of training with (LHTL; n=10) or without (placebo; n=6) Live High-Train Low modalities. Total hemoglobin mass was measured before and after training by a carbon monoxide rebreathing technique. After training, subjects performed two maximal exercise bouts separated by isovolumic hemodilution (phlebotomy and/or plasma volume expander) to readjust red blood cell volume and plasma volume to baseline values. Blood samples were obtained before and after exercise to assess hematocrit and blood and plasma viscosity.Training session (LHTL and placebo) increased hematocrit (Hct) in all subjects but without any significant change in blood viscosity. The decrease in plasma viscosity in all groups may explain this result. Isovolumic hemodilution caused a drop of Hct without any significant change in blood viscosity at rest. Maximal exercise increased Hct, blood and plasma viscosities in both groups, regardless of isovolumic hemodilution. However, peak hemorheological values after exercise were lower after isovolumic hemodilution.In conclusion, while acute increase in Hct during exercise caused an increase of blood viscosity, the chronic increase of Hct induced by training session did not result in a rise in blood viscosity. The lowering of plasma viscosity during training may compensate for the increase of Hct, hence limiting its impact on blood viscosity.


PubMed | University of Zürich and Ecole Nationale des Sports de Montagne
Type: Journal Article | Journal: Experimental physiology | Year: 2016

What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not.

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