Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Growth hormone (GH) may stimulate water loss during exercise by activating sweating. This study investigated GH secretion and water loss during sequential cycling and running, taking postural changes into account. The two exercise segments had similar durations and were performed at the same relative intensity to determine their respective contributions to water loss and the plasma volume variation noted in such trials. Eight elite triathletes first performed an incremental cycle test to assess maximal oxygen consumption. Then, the triathletes performed one of two trials in randomized order: constant submaximal cycling followed by treadmill running (C 1 –R 2) or an inversed succession of running followed by cycling (R 1 –C 2). Each segment of both trials was performed for 20 minutes at ,75% of maximal oxygen consumption. The second trial, reversing the segment order of the first trial, took place two weeks later. During cycling, the triathletes used their own bicycles equipped with a profiled handlebar. Blood sampling (for GH concentrations, plasma viscosity and plasma volume variation) was conducted at rest and after each segment while water loss was estimated from the post-and pre-measures. GH increases were significantly lower in R 2 than C 2 (72.2650.1 vs. 164.06157 ng.ml 21 .min 21 , respectively; P,0.05). Water loss was significantly lower after C 1 –R 2 than R 1 –C 2 (11056163 and 12356153 ml, respectively; P,0.05). Plasma volume variation was significantly negative in C 1 and R 1 (26.1562.0 and 23.1665.0%, respectively; P,0.05), not significant in C 2 , and significantly positive for seven subjects in R 2 (4.0563.1%). We concluded that the lower GH increases in R 2 may have contributed to the smaller reduction in plasma volume by reducing sweating. Moreover, this lower GH response could be explained by the postural change during the transition from cycling to running. We recommend to pay particular attention to their hydration status during R 1 which could limit a potential dehydration during C 2 .
ISSN: 1932-6203

hal-01136734
https://hal.univ-antilles.fr/hal-01136734
https://hal.univ-antilles.fr/hal-01136734/document
https://hal.univ-antilles.fr/hal-01136734/file/Galy%20et%20al.%20-%202014%20-%20Sequential%20exercise%20in%20triathletes%20Variations%20in%20GH%20and%20water%20loss.pdf
DOI : 10.1371/journal.pone.0096145

Éditeur(s) : HAL CCSD IOP Publishing
Résumé : We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non-metrological institutes are compared. For the first time, corrections for the laser beam diffraction and the self-attraction of the gravimeters are implemented. The gravity observations are also corrected for geophysical gravity changes that occurred during the comparison using the observations of a superconducting gravimeter. We show that these corrections improve the degree of equivalence between the gravimeters. We present the results for two different combinations of data. In the first one, we use only the observations from the metrological institutes. In the second solution, we include all the data from both metrological and non-metrological institutes. Those solutions are then compared with the official result of the comparison published previously and based on the observations of the metrological institutes and the gravity differences at the different sites as measured by non-metrological institutes. Overall, the absolute gravity meters agree with one another with a standard deviation of 3.1 µGal. Finally, the results of this comparison are linked to previous ones. We conclude with some important recommendations for future comparisons.
ISSN: 0026-1394

hal-00853755
https://hal.archives-ouvertes.fr/hal-00853755
DOI : 10.1088/0026-1394/50/3/257

Éditeur(s) : HAL CCSD Editions EDP
ISSN: 1290-3612

hal-01136953
https://hal.archives-ouvertes.fr/hal-01136953

Éditeur(s) : HAL CCSD University of Uludag
Résumé : International audience
The aim of this study was to compare the core temperature (TC) and markers of hydration status in athletes performing a half Ironman triathlon race in hot and humid conditions (27.2 ± 0.5°C, relative humidity was 80 ± 2%). Before and immediately after the 2012 Guadeloupe half Ironman triathlon, body mass and urine osmolarity (mean ± SD) were measured in 19 well-trained male triathletes. TC was measured before and after the race, and at each transition during the event, using an ingestible pill telemetry system. Ambient temperature and heart rate (HR) were measured throughout the race. Mean ± SD performance time was 331 ± 36 minutes and HR was 147 ± 16 beats·min-1. Wet bulb globe temperature (WBGT) averaged 25.4 ± 1.0°C and ocean temperature was 29.5°C. The average TC at the beginning of the race (TC1) was 37.1 ± 0.7°C; it was 37.8 ± 0.9°C after swimming (TC2), 37.8 ± 1.0°C after cycling (TC3), and (TC4) 38.4 ± 0.7°C after running. Body mass significantly declined during the race by 3.7 ± 1.9 kg (4.8 ± 2.4%; p < 0.05), whereas urine osmolarity significantly increased from 491.6 ± 300.6 to 557.9 ± 207.9 mosm·L-1 (p < 0.05). Changes in body mass were not related to finishing TC or urine osmolarity. Ad libitum fluid intake appears applicable to athletes acclimatized to tropical climate, when performing a half Ironman triathlon in a warm and humid environment.
ISSN: 1303-2968

hal-01136698
https://hal.univ-antilles.fr/hal-01136698
https://hal.univ-antilles.fr/hal-01136698/document
https://hal.univ-antilles.fr/hal-01136698/file/Baillot%2C%20Hue%20-%202015%20-%20Hydration%20and%20Thermoregulation%20during%20a%20Half-Ironman%20Performed%20in%20Tropical%20Climate.pdf

Éditeur(s) : HAL CCSD ACSM
Résumé : International audience
The aim of this study was to examine the effects of the cycle-run and run-cycle successions of the triathlon and duathlon, respectively, on respiratory muscle strength and endurance. Methods: Respiratory muscle strength was assessed by measuring maximal inspiratory (P1max) and expiratory {PEmax) pressures. Respiratory muscle endurance was assessed by measuring the time limit (Tlim). Twelve triathleles participated in a three-trial protocol. The first trial consisted of an incremental cycle test to assess the maximal oxygen uptake (VO2max) of triathletes. Trial 2 consisted of 20 min of cycling followed by 20 min of running (C-R), and trial 3 consisted of 20 min of running followed by 20 min of cycling (R-C). Trials 2 and 3 were performed at the same metabolic intensity (% VO2max). P1max and P1max were measured before and 10 min after C-R and R-C, and I min after the post-C-R and post-R-C Tlim measurements (P1max l'). Tlim was measured I d before and 30 min after C-R and R-C. Results: The results showed a significant decrease in P1max after C-R (126.7 ± 4.3 cmH2O, P < 0.05) and R-C (123.7 ± 4.9 cmH2O, P < 0.05) compared with the baseline values (130 ± 3.8 and 129.6 ± 4.3 cmH2O, respectively). P1max 1' showed a significantly greater decrease after R-C versus C-R(111.2 ± 5.5 cmH2O vs 121.2 ± 3.9 cmH2O,respectively, P < 0.001). Tlim after C-R (3.3 ± 0.3 min) decreased significantly compared with baseline values (4.19 ± 0.3min and 4.02 ± 0.3 min, respectively). However, the Tlim decrease after R-C was significantly greater than after C-R (P < 0.001). Conclusion: We concluded that respiratory muscle strength and endurance were less decreased after the cycle-run succession and that cycling induced a greater decrease in respiratory muscle endurance than running.
Medicine & Science in Sports & exercise

hal-00720796
https://hal.univ-antilles.fr/hal-00720796

Éditeur(s) : HAL CCSD
Résumé : International audience
ISSN: 00029556

hal-01633115
https://hal.archives-ouvertes.fr/hal-01633115
https://hal.archives-ouvertes.fr/hal-01633115/document
https://hal.archives-ouvertes.fr/hal-01633115/file/Manuscript%20AJP%202477%20version%202.pdf
DOI : 10.5406/amerjpsyc.130.4.0455

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The six-minute walk test is a well-established submaximal exercise reflecting the functional status and the clinical severity of sickle cell patients. The aim of the present cross-sectional study was to investigate the biological determinants of the six-minute walk test performance in children with sickle cell anemia. Hematological and hemorheological parameters, pulmonary function and the six-minute walk test performance were determined in 42 children with sickle cell anemia at steady state. The performance during the six-minute walk test was normalized for age, sex and height and expressed as percentage of the predicted six-minute walk distance. We showed that a high level of anemia, a low fetal hemoglobin expression and low red blood cell deformability were independent predictors of a low six-minute walk test performance. This study describes for the first time the impact of blood rheology in the six-minute walk test performance in children with sickle cell anemia.
ISSN: 1932-6203

inserm-00922110
http://www.hal.inserm.fr/inserm-00922110
http://www.hal.inserm.fr/inserm-00922110/document
http://www.hal.inserm.fr/inserm-00922110/file/2013_Waltz_-_Hematological_and_hemorheological_determinants_6_minutes.pdf
DOI : 10.1371/journal.pone.0077830

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Because of the metabolic changes induced by a physical activity, the hemorheological properties of patients with sickle cell anemia could be further impaired and increase the risks for vaso-occlusive complications. However, few studies suggest that moderate physical activity could be beneficial rather than harmful in patients with sickle cell anemia (SCA). However, the definition of what can be considered as a moderate physical activity in SCA patients is imprecise. The present study tested the effects of a short incremental cycling exercise test conducted until the first ventilatory threshold on different biomarkers. Hematological and hemorheological parameters were compared between 8 patients with SCA and 13 healthy subjects (CONT) before, immediately after the end of the exercise and at 12, 36 and 60 hours after the exercise. We observed no significant hematological or hemorheological alteration induced by the exercise in the two groups. However, the exercise resulted in a delayed improvement of the red blood cell disaggregation threshold at 36 and 60 hrs after exercise in the SCA group which was paralleled to the decrease in the platelet count in this group. The present study suggests that such an exercise might be beneficial for microcirculatory blood flow.
ISSN: 1386-0291

hal-01137567
https://hal.univ-antilles.fr/hal-01137567

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Purpose: This study compares the effects of neutral temperature, cold and ice-slush beverages, with and without 0.5% menthol on cycling performance, core temperature (T co) and stress responses in a tropical climate (hot and humid conditions). Methods: Twelve trained male cyclists/triathletes completed six 20-km exercise trials against the clock in 30.7uC60.8uC and 78%60.03% relative humidity. Before and after warm-up, and before exercise and every 5 km during exercise, athletes drank 190 mL of either aromatized (i.e., with 0.5 mL of menthol (5 gr/L)) or a non-aromatized beverage (neutral temperature: 23uC60.1uC, cold: 3uC60.1uC, or ice-slush: 21uC60.7uC). During the trials, heart rate (HR) was continuously monitored, whereas core temperature (T co), thermal comfort (TC), thermal sensation (TS) and rate of perceived exertion (RPE) were measured before and after warm-up, every 5 km of exercise, and at the end of exercise and after recovery. Results: Both the beverage aroma (P,0.02) and beverage temperature (P,0.02) had significant and positive effects on performance, which was considerably better with ice-slush than with a neutral temperature beverage, whatever the aroma (P,0.002), and with menthol vs non-menthol (P,0.02). The best performances were obtained with ice-slush/menthol and cold/menthol, as opposed to neutral/menthol. No differences were noted in HR and T co between trials. Conclusion: Cold water or ice-slush with menthol aroma seems to be the most effective beverage for endurance exercise in a tropical climate. Further studies are needed to explore its effects in field competition.
ISSN: 1932-6203

hal-01135125
https://hal.univ-antilles.fr/hal-01135125
https://hal.univ-antilles.fr/hal-01135125/document
https://hal.univ-antilles.fr/hal-01135125/file/Riera%20et%20al.%20-%202014%20-%20Physical%20and%20perceptual%20cooling%20with%20beverages%20to%20increase%20cycle%20performance%20in%20a%20tropical%20climate%284%29.pdf
DOI : 10.1371/journal.pone.0103718

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Tropical climate imposes a high level of physiological stress, which could modify the target heart rate in training load prescription, as the recommendations are often determined by maximal oxygen uptake testing in temperature-neutral laboratories. To test this hypothesis, 7 highlevel cyclists performed two randomised maximal tests in neutral (19.2±0.9 ◦C; 51.7±1.3% RH) and Tropical environment (25.8±1.1 ◦C; 63.7±2.3% RH). Neither maximal oxygen uptake nor ventilatory threshold was influenced by the environmental conditions. However, ventilation (p < 0.005) and the respiratory equivalent in O2 (p < 0.05) were significantly higher in the Tropical environment, whereas maximal power output and the time to attain maximal oxygen uptake were significantly lower (p < 0.05 for both). Moreover, the ventilatory cost of cycling (expressed in LW−1) was significantly greater in the Tropical condition (0.40±0.03 LW−1 vs. 0.32±0.05 LW−1, in Tropical vs. Neutral; condition effect: p < 0.005; condition×time: p < 0.001). Rectal temperature was influenced by neither the environmental conditions nor exercise (36.7±0.1 and 37.0±0.1 ◦Cvs. 36.8±0.1 and 37.1±0.2 ◦C, in Tropical vs. Neutral, before and after exercise) but was influenced by condition×time (p < 0.05). The heart rate (HR) values usually used for training prescription were not significantly different (154±5 bpm vs. 156±4 bpm and 172±4 bpm vs. 167±4 bpm in Tropical vs. Neutral climate, for the first and second thresholds, respectively). We concluded that the usual parameters measured during maximal exercise to establish training programs are not impaired in moderate Tropical environment. Nevertheless, the thermal stress attested by the increased ventilatory cost of cycling could have prevented the cyclists from performing a true maximal test in Tropical conditions.
ISSN: 1440-2440

hal-00703461
https://hal.univ-antilles.fr/hal-00703461
DOI : 10.1016/j.jsams.2009.11.004

Éditeur(s) : HAL CCSD PubMed
Résumé : International audience
This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs) and 8 Caucasian (NMEL-G, 22.9±4.9) elite futsal players, using tests of jump-and-reach (CMJ), agility (T-Test), repeated sprint ability (RSA), RSA with change-of-direction (RSA-COD), sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT). The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P=0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P=0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P=0.05. MEL-G height was significantly related to CMJ (r=0.706, P=0.01), CMJpeakP (r=0.709, P=0.01) and T-Test (r=0.589, P=0.02). No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO2max. Between groups, the percentage decrement (%Dec) in RSA-COD was significantly lower in MEL-G than NMEL-G (P=0.05), although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P=0.697. This study presents specific anthropometric (significantly lower height) and physiological (significantly greater agility) reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania.
ISSN: 0860-021X

hal-01146219
https://hal.univ-antilles.fr/hal-01146219
DOI : 10.5604/20831862.1140428

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
Objectifs. - Évaluer les effets du triathlon classique (1,5 km natation, 40 km cyclisme, 10 km course à pied) sur la capacité de diffusion pulmonaire (DLCO) 24 heures après la compétition. Méthodes et résultats. - Dix triathlètes masculins (21,5 ± 2,8 ans) ont effectué une spirométrie et une mesure de la capacité de diffusion pulmonaire avant la compétition (pré-T) et 24 heures après l'épreuve (post-T). Les résultats montrent une diminution significative du volume expiratoire maximal en 1 s (5,17 ± 0,4 L.s-1 contre 4,09 ± 0,6 L.s-1) et du débit expiratoire maximal 25-75 % de la capacité vitale (6,98 ± 0,2 L.s-1 contre 4,90 ± 0,2 L.s-1). En revanche, les résultats ne montrent pas de différence significative entre les DLCO pré-T et post-T (38,1 ± 3,3 mL.min-1.mmHg-1 contre 37,1 ± 3,7 mL.min-1.mmHg-1) ni les ratios DLCO/VA (5,59 ± 0,5 mL.min-1.mmHg-1.A-1 contre 5,55 ± 0,7 ml.min-1.mmHg-1.A-1). Conclusion. - La DLCO est normale chez les triathlètes 24 heures après une compétition classique. Ceci peut traduire l'absence de lésions alvéolocapillaires pendant le triathlon. La baisse de la DLCO rapportée deux heures après un exercice dans la littérature peut s'expliquer par la baisse du volume sanguin pulmonaire qui apparaît comme un phénomène transitoire. Cependant, la baisse des débits pulmonaires observée 24 heures après le triathlon suggère la persistance chez les triathlètes d'un syndrome obstructif bronchique.
ISSN: 0765-1597

hal-00720522
https://hal.univ-antilles.fr/hal-00720522
https://hal.univ-antilles.fr/hal-00720522/document
https://hal.univ-antilles.fr/hal-00720522/file/Article_3_.pdf

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
The aim of this study was to examine the influence of exercise intensity and session duration on rating of perceived exertion (RPE) in adolescent Taekwondo (TKD) athletes. Twelve male youth competitive TKD athletes, aged between 13 and 18 years took part in this study. Training data (368 individual sessions) were collected during the 12 weeks of the precompetitive TKD season. Daily training load was calculated using the heart rate and the session-RPE. Exercise intensity was also classified in five zones [i.e. 5060%, 6170%, 7180%, 8190% and 91100% of maximal heart rate (HRmax)] and the time spent in each zone was expressed as percentage of total session time. The analysis of variance showed a significantmain effect for zone (pB0.001) with most of the time (69%) spent at intensities between 61 and 90% of HRmax, and only 10% spent above 91% (mean differences compared to the other zones ranging from 6.6% versus zone 1 to 14.8% versus zone 3; pB0.0001). The individual correlation between session-RPE and HR-based methods were moderate to large. The stepwise multiple regression showed that RPE was influenced mainly by the time spent in the high intensity zone that explained 22.1% of the variance in RPE. Session duration accounted for only an additional 3.2%. The results suggest the time spent at high-intensity (i.e. between 91 and 100% HRmax) and only marginally the session duration influences theRPE referred to the whole training session. This seems to confirm that the determination of the TL multiplying the RPE andsession duration is acceptable.
ISSN: 1746-1391

hal-01163939
https://hal.univ-antilles.fr/hal-01163939
DOI : 10.1080/17461391.2012.691115

Éditeur(s) : HAL CCSD Human Kinetics
Résumé : International audience
In order to study the acclimatization process over 14 days of exposure to tropical climate, 9 triathletes performed 4 outdoor indirect continuous multistage tests in both thermoneutral and tropical conditions. The thermoneutral test (TN, 14 C, 45% rh) was performed before traveling to the tropical area (Martinique, FWI). The tropical tests were performed 2, 8, and 14 days after arrival (32.9 C, 78% rh). During each trial, we measured tympanic temperature, sweat rate, body mass loss, heart rate (HR), and performance. The results showed that 1) the mean tympanic temperature was greater in T2 (P < .001), T8 (P < .01) and T14 (P < .01) than in TN and significantly lower in T14 than in T2 (P < .05); 2) the mean sweat rate was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 3) the body mass loss after trials was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 4) the mean HR and HR at rest were significantly higher (P < .005) in T2 than in TN, T8, T14 and the mean HR was significantly lower (P < .05) in T14 than in the other trials; and 5) the performance time was significantly lower in T2 (P < 0.02), T8 (P < 0.03) and T14 (P < 0.05) than in TN. We concluded that 14 days of exposure.
ISSN: 1066-7814

hal-00720075
https://hal.univ-antilles.fr/hal-00720075
https://hal.univ-antilles.fr/hal-00720075/document
https://hal.univ-antilles.fr/hal-00720075/file/02.Voltaire_551_.pdf

Éditeur(s) : HAL CCSD International Federation of Sports Medicine
Résumé : International audience
To study the exercise-induced arterial hypoxaemia (EIAH) kinetics in a world class Ironman triathlete at ventilatory threshold (TH vent), the authors simulated the cycle-run succession (CR, 20 min + 20 min) and a 20-min isolated run (R). Although 'moderate EIAH' was noted during CR, the SpO 2 kinetics of the isolated R reflected 'severe EIAH' from minutes 7 to 15 with a nadir of 85 % SpO 2 that stabilised at 90 % SpO 2 from minute 15 on. The physiological processes involved in these responses are discussed. These data indicate a systematic 'moderate EIAH' in a world class Ironman champion during CR and R at TH vent and a temporary 'severe EIAH' during R, which was attenuated when running was successive to cycling. The physiological significance of this phenomenon remains unclear, however, and further experiments are needed.
ISSN: 1528-3356

hal-01152346
https://hal.univ-antilles.fr/hal-01152346

Éditeur(s) : HAL CCSD Human Kinetics
Résumé : International audience
The authors investigated the anthropometric and physiological characteristics of young Guadeloupian competitive swimmers in relation to swimming performance and compared the abilities of these children with those of the young white swimmers reported in the literature. All 2004 competitive swimmers between 10 and 14 y old (126 children, 61 boys and 65 girls, 12.0 ± 1.3 y) from Guadeloupe underwent anthropometric measurements and physiological and performance testing. Six boys on the French national swimming team are referred to hereafter as the 2011 elite subgroup. Anthropometric parameters, a jump-and-reach test, glide, and estimated aerobic power (eVO2max) were assessed in terms of swimming-performance analysis through a 400-m test. This study demonstrated that the Guadeloupian swimmers had more body fat than most age-matched white swimmers but had very poor hydrostatic lift; they had higher peak jump height and they swam as well as their white counterparts. The variability in 400-m performance between subjects was best described by glide, age, and eVO2max. Compared with the group of boys with the same age, the 2011 elite subgroup was significantly better for arm span, peak jump height, glide, and 400-m and 15-m performances. Further research is needed to investigate motor organization and energy cost of swimming in Afro-Caribbean swimmers.
ISSN: 1555-0265

hal-01137258
https://hal.univ-antilles.fr/hal-01137258
https://hal.univ-antilles.fr/hal-01137258/document
https://hal.univ-antilles.fr/hal-01137258/file/Hue%20et%20al.%20-%202013%20-%20Anthropometric%20and%20physiological%20characteristics%20in%20young%20Afro-Caribbean%20swimmers%20A%20preliminary%20study.pdf

Éditeur(s) : HAL CCSD PubMed
Résumé : International audience
To investigate thermal response, hydration behaviour and performance over flatwater kayaking races in tropical conditions (36.8°C and 68 % rh). Five internationally-ranked subjects participated in the 2012 Surfski Ocean Racing World Cup in Guadeloupe to the “Ze Caribbean Race 2012” [i.e., a 35-km downwind race]. Core temperature (T°C) and heart rate (HR) were measured using portable telemetry units whereas water intake was deduced from backpacks absorption. The kayakers were asked to rate both their comfort sensation and thermal sensation on a scale before and after the race. The performance was related to an increase in T°C, high HR and low water intake (WI); and (2) high values of final T°C were related to high pre T°C and greater increases in T°C being obtained with low pre T°C and (3) WI being related to high pre T°C. The present study demonstrated that the fastest kayakers were those able to paddle at the highest intensities, increasing their T°C and drinking little water without any interference from thermal sensations. Water intake was positively related to pre-race T°C, which reinforces the importance of beginning surfski races with a low T°C. This study demonstrated that well-trained kayakers drinking ad libitum were able to anticipate their intensity/heat storage ratio to prevent heat illness and severe dehydration and maintain high performance.
ISSN: 0860-021X

hal-01137286
https://hal.univ-antilles.fr/hal-01137286

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Growth hormone (GH) may stimulate water loss during exercise by activating sweating. This study investigated GH secretion and water loss during sequential cycling and running, taking postural changes into account. The two exercise segments had similar durations and were performed at the same relative intensity to determine their respective contributions to water loss and the plasma volume variation noted in such trials. Eight elite triathletes first performed an incremental cycle test to assess maximal oxygen consumption. Then, the triathletes performed one of two trials in randomized order: constant submaximal cycling followed by treadmill running (C 1 –R 2) or an inversed succession of running followed by cycling (R 1 –C 2). Each segment of both trials was performed for 20 minutes at ,75% of maximal oxygen consumption. The second trial, reversing the segment order of the first trial, took place two weeks later. During cycling, the triathletes used their own bicycles equipped with a profiled handlebar. Blood sampling (for GH concentrations, plasma viscosity and plasma volume variation) was conducted at rest and after each segment while water loss was estimated from the post-and pre-measures. GH increases were significantly lower in R 2 than C 2 (72.2650.1 vs. 164.06157 ng.ml 21 .min 21 , respectively; P,0.05). Water loss was significantly lower after C 1 –R 2 than R 1 –C 2 (11056163 and 12356153 ml, respectively; P,0.05). Plasma volume variation was significantly negative in C 1 and R 1 (26.1562.0 and 23.1665.0%, respectively; P,0.05), not significant in C 2 , and significantly positive for seven subjects in R 2 (4.0563.1%). We concluded that the lower GH increases in R 2 may have contributed to the smaller reduction in plasma volume by reducing sweating. Moreover, this lower GH response could be explained by the postural change during the transition from cycling to running. We recommend to pay particular attention to their hydration status during R 1 which could limit a potential dehydration during C 2 .
ISSN: 1932-6203

hal-01158212
https://hal.univ-antilles.fr/hal-01158212
DOI : 10.1371/journal.pone.0096145

Éditeur(s) : HAL CCSD
Résumé : International audience
To determine whether exercise modality affects arterial hypoxemia (EIAH) during training-intensity exercise, 13 triathletes performed 20 min of cycling (C) followed by 20 min of running (R): C-R, and two weeks later, 20 min of R followed by 20 min of C:R-C. Each trial was performed at an intensity slightly above the ventilatory threshold and close to the daily training intensity (75 % of VO2max). Ventilatory data were collected continuously using an automated breath-by-breath system. Partial pressure of oxygen in arterial blood (PaO2) was measured after each C and R segment and arterial oxyhemoglobin saturation (SpO2) was monitored continuously via pulse oximetry. The metabolic rate was similar across modalities and trials, i.e., C-R (53.8 +/- 3.8 vs. 51.1 +/- 5.3 ml.min(-1).kg(-1)) and R-C (52.2 +/- 4.5 vs. 53.2 +/- 4.6 ml.min(-1).kg (-1)). EIAH showed significantly greater severity for R compared to C irrespective of the order (p < 0.05 for both trials). R values of PaO2 (and SpO2) for C-R and R-C were 88.7 +/- 6.0 mm Hg (93.0 +/- 0.6 % SpO2) and 86.6 +/- 7.3 mm Hg (93.5 +/- 0.6 % SpO2) and C values were 93.7 +/- 8.4 mm Hg (95.4 +/- 0.4 % SpO2) and 91.4 +/- 5.4 mm Hg (94.8 +/- 0.3 % SpO2). R ventilatory data described a significantly different breathing pattern than C, with higher respiratory rate (35.9 b.min(-1) vs. 51.1 b.min(-1) for C-R, p < 0.01; and 50.0 b.min(-1) vs. 41.5 b.min(-1) for R-C, p < 0.01) and lower tidal volume (2636 ml vs. 2282 ml for C-R, p < 0.02 and 2272 ml vs. 2472 ml for R-C, p < 0.05). We concluded that EIAH was greater during running than cycling for a similar metabolic rate corresponding to training intensity and that EIAH could thus be considered dependent on exercise modality.
Internation Journal of Sports Medicine

hal-00720806
https://hal.univ-antilles.fr/hal-00720806
https://hal.univ-antilles.fr/hal-00720806/document
https://hal.univ-antilles.fr/hal-00720806/file/sm290.pdf

Éditeur(s) : HAL CCSD SAGE Publications
Résumé : International audience
ISSN: 1010-5395

hal-01679045
https://hal.univ-antilles.fr/hal-01679045
DOI : 10.1177/1010539517735414