Influence des paramètres anthropométriques sur la performance en aviron au niveau national

Introduction. – L'objectif de cette étude est d'observer l'influence des paramètres anthropométriques sur la performance en aviron, chez des rameurs de niveau national et international.Synthèse des faits. – Les mesures anthropométriques ont été réalisées sur 88 rameurs (dont 11 évoluant au niveau international) lors des championnats de France de 2002. Ces mesures ont été corrélées aux performances réalisées sur ergomètre et en bateau. Des différences significatives sont mises en évidence entre les caractéristiques anthropométriques des rameurs de niveau national et international. Ces caractéristiques semblent être reliées directement aux performances ergométriques et non à celles réalisées en bateau.Conclusion. – L'influence des caractéristiques anthropométriques sur la performance en aviron pourrait être modifiée en fonction des niveaux de compétition.Aim. – Observe the influence of anthropometrics characteristics on rowing performance, at national and international level.Results. – Anthropometrics measurements of 88 rowers (included 11 international rowers) were realized during the national championships, data were correlated to ergometer and boat performances. Significant differences appear between anthropometrics characteristics of national and international rowers. Anthropometrics parameters seem related to ergometer performance but not to boat performances.Conclusion. – The influence of anthropometrics characteristics on rowing performance could be modified by the competitive level.     

Effet de l'entraînement sur l'anabolisme musculaire : analyse de la réceptivité à la testostérone

This study analysed consequences of testosteronemia changes on anabolic process after endurance physical training. During 8 weeks, rats were physically trained in endurance tests. Plasmatic testosterone concentrations were significantly decreased (P < 0.05), weight of three skeletal muscles (soleus, EDL, tibialis anterior) and total muscular protein concentrations were significantly increased (P < 0.05). After endurance physical training muscular hypertrophy was well evidenced (P < 0.05). The analyse of testosterone muscular receptor was performed, permitting two essentials conclusions: according to fibre histological profiles, hormonal receptivity was more profound on fast-twitch muscles (P < 0.05); this hormonal receptivity persists as well as testosteronemia, which was significantly diminished with endurance training.     

Effets du repas précompétitif sur la perception de l'effort et sur la glycémie lors d'un exercice de pédalage

The first purpose of the present study was to investigate the effect of three different preexercise meals on perceived exertion and glycaemia during a one-hour bicycle exercise at 80% VO₂ max. The second purpose of this study was to determine the relationship between glycaemia and perceived exertion. Eight athletes (age: 24.6 ± 2.7 years, weight: 78.0 ±6.8 kg, height: 182.6 ± 9.9 cm) completed three assessment sessions, each being preceeded by one of the following meals, ingested 3 h before exercise: 400 mL of water, 400 mL of water and 75 g of glucose, and 100 mL of water and 375 g of potatoes. The subjects 'perceived exertion were measured at times 6, 15, 30, 45, 60 min and glycaemia at 0, 30, 60 min of the exercise. The results showed that perceived exertion (RPE and ETL) of each meal increased as a function of time (P <- 0.05) whereas glycaemia did not differ except for the glucose meal between 30 min and 1 h(P < 0.02). There was no significant difference in ratings of perceived exertion among any meal whereas glycaemia was different between the three conditions only at the beginning and the middle of the exercises (P < 0.04 and P < 0.02, respectively). Moreover, the vectorial angles between the variables ofperceived exertion and the glycaemia are close to 90 °. These results would suggest that perceived exertion does not seem to be affected by the three preexercise meals used in our study. Perceived exertion is not correlated to glycaemia changes during one-hour high intensity exercise. The results would, therefore, suggest that glycaemia is not a contributor signal of perceived exertion in this study. It seems that physiological factors other than glycaemia may have mediated the perceptual intensity at exhaustion. The respiratory-metabolic signals of exertion which are most pronounced at high relative exercise intensity are suggested to influence the perceptual signal of exertion.     

Blessures musculotendineuses à répétition survenant sur un terrain métabolique perturbé : à propos d'une observation de maladie de Gilbert chez un sprinter de niveau national

Gilbert's disease is a constitutional disorder of bilirubin glycosilation in the liver. Physical exercise increases free bilirubin in blood, and the disturbance of the liver's metabolic activity could be the origin of muscular and tendon injuries. The diagnosis of Gilbert's disease is made through biological tests, which are necessary as prevention can obviate critical situations. Other metabolic constitutional disorders could be responsible for similar situations, therefore in cases of frequent muscular and tendon injuries, accurate biological investigations must be made.     

Effets de l'entraînement sur les potentiels aérobie et anaérobie de jeunes nageurs. Exercice réalisé avec les brasEffect of training on aerobic and anaerobic capacity in young swimmers. Exercise performed with arms

Aims – Investigate the influence of exercise training on the aerobic and anaerobic capacities of young swimmers.Methods – Ten male swimmers aged 15.2 ± 3.8 years participated: five sprint specialists and five middle-distance specialists. Each subject performed, an arm ergocycle, two laboratory tests, a maximal incremental exercise test and a force–velocity test, once in February (T1) and then again in June (T2).Results – For all subjects combined (n=10), the results showed a significant increase in maximal anaerobic power (p < 0.01) between T1 and T2. Aerobic capacity did not change significantly between the two tests in either group.Conclusion – This study demonstrates the interest of evaluating aerobic and anaerobic capacity in young swimmers during arm exercise. The change in results over the 5-month period between the two tests indicates the importance of scheduling exercise tests during the course of athletic training programs.     

Les effets d''une exposition répétée à l''oxygène hyperbare (OHB) sur la performance physique du sportif

Objectifs. – Le but de cette étude a été de vérifier que l'hyperoxie permettait d'augmenter les performance d'un exercice physique.Méthodes. – Vingt-deux sportifs de spécialités différentes, « explosif » (musculation) et « endurance » (cyclisme) ont été étudiés. Les groupes « explosif » et « endurance » comportaient respectivement six sujets hyperoxie + trois contrôles et six sujets hyperoxie + sept contrôles. Douze séances d'entraînement de 90 minutes ont été réalisées : groupe hyperoxie = 100 % d'oxygène à 1,6 b (PO2 = 160 kPa), groupe témoin = pression atmosphérique normale (PO2 = 21 kPa). Des paramètres anthropométriques et biologiques , la force utile maximale (groupe « explosif ») et la VO2 max (groupe « endurance ») ont été mesurés avant et après les 12 séances. L'évolution des puissances développées à la fréquence cardiaque correspondant au seuil de 4 mmol d'acide lactique a été suivie dans le groupe « endurance ».Résultats. – Il n'existait pas de différence significative entre les groupes pour les paramètres anthropométriques, sanguins et la VO2 max. Le groupe « explosif » hyperoxie présentait à la fin des séances, une force utile maximale plus importante (p = 0,03) que celle des témoins. Le groupe « endurance » présentait une augmentation plus importante (p < 0,05) des puissances sous-maximales que le groupe témoin.Conclusion. – L'hyperoxie permet une optimisation de l'entraînement du sportif.Aims. – Evaluate the effect of hyperbaric oxygen on physical exercise performance.Methods. – Twenty two athletes with different specialties: “explosive” (musculation) and “endurance” (cycling), were studied. The “explosive” and “endurance” groups included respectively 6 “hyperoxy” subjects + 3 controls and 6 “hyperoxy” subjects + 7 controls. Twelve 90 min-sessions of training were scheduled: “hyperoxy” group = 100% oxygen at 1.6 b (PO₂ = 160 kPa), control group = atmospheric pressure (PO₂ =21 kPa). Anthropometric and biologic parameters, useful maximum strength (“explosive” group) and VO_2max (“endurance” group) were assessed before and after the 12 sessions. Modifications of strength developed at the cardiac frequency corresponding to the 4 mmol threshold of lactic acid were noted in the “endurance” group.Results. – No difference was noted between the two groups in the variations of the anthropometric and biologic parameters as well as in the VO_2max determinations. The “explosive/hyperoxy” group developed, at the end of the sessions, a more important (P = 0.03) increase of the useful maximum strength that controls. The “endurance” group developed a more important increase (P < 0.05) of sub maximum powers that controls.Conclusion. – Hyperbaric oxygen optimize athletic training.     

Alimentation calcique et effet de l'entraînement physique sur l'os

Physical exercise is able to influence bone structure. In the principal part of cases, physical training results in an enhanced bone density when in any case overtraining could decrease bone density. Numerous factors are involved in the effect of physical training on bone, dietary calcium supply being one. Numerous epidemiological surveys have shown that the daily calcium supply in the French population is between 500 and 1,200 mg/24 hours. Thus part of the French population is under the recommended intake of 1,000 mg. It was proposed that physical training could improve calorie intake and consequently calcium supply. The main objective of this paper is the relationship between exercise and bone structure: second, literature is used to present the role of dietary calcium on bone structure. Finally, the data of a survey in a French population are used in order to define to what extent calcium dietary supply of different sports groups agree with the dietary recommended allowance. They report that calcium supply is influenced by the type of sport, strength trained atheletes enhance calcium intake while endurance trained atheletes present lower calcium intake.     

Influence de l''hydratation sur la sécrétion d''hormone de croissance induite par l''exerciceHydration influence on exercise-induced growth hormone secretion

Aim – Study was then to investigate hydration influence on exercise-induced GHh secretion.Methods and results – Seven healthy men underwent a submaximal rectangular cycling exercise for 30 minutes to 150 watts during two sessions. A first one without any water intake and a second one with ingestion of spring water corresponding to the volume of water lost during the first session. Plasma volume decrease was significantly higher during the first session (p < 0.05). Total GH secretion was significantly lower during this session (p < 0.05).Conclusion – A moderate dehydration decreases exercise-induced GH response. Thus, hypovolemia may exert a negative feed back on GH secretion, during exercise.     

Influence d’une compétition de rugby sur le taux de cortisol salivaireInfluence of an international rugby mah upon the concentration of salivary cortisol

Introduction – Measure the influence of a sporting event (in this case an international rugby match) upon the concentration of salivary cortisol.Synthesis of facts – In order to take our study to a successful conclusion, we took salivary samples from the players during the event as well as at the time of a rest day. These concentrations are measured thanks to a radio immunoassay technique. The sporting event  has resulted in a 75% cortisol level rise. This increase reflects both a physiological and a psychological response to a stressful stimulation. The value of the cortisol before the event is also higher (85%) than the one measured at the same time of day during the rest day.Conclusion – This result shows that the sporting event has a positive correlation with the level of the salivary cortisol that it is to say a cognitive anticipation of the subjects.     

Composante lente de VO2 chez l''enfant prépubère lors d''exercices rectangulaires d''intensité élevéeThe slow component of VO2 uptake kinetics during high-intensity exercise in prepubertal children

Aim – The aim of the present study was to investigate the VO2 uptake slow component in prepubertal children of different aerobic capacity during high intensity exercise.Method – Twenty three (12 well-trained and 11 untrained) prepubertal children took part in two constant-power tests performed at intensities corresponding to 80% of the anaerobic threshold and 90% of maximal aerobic power. VO2 kinetics during both constant-power tests was determine using a monoexponential + linear term model.Results/conclusion – Our results demonstrated the existence of a slow component during heavy intensity exercise in prepubertal children, as previously described in adults. The magnitude of this slow component did not differ between trained swimmers and untrained children exercising at the same relative intensity, provided that the whole VO2 response was considered.     

Application des opérateurs logiques (booléens) à la recherche bibliographique sur Internet en médecine du sport

Last year, use of logic operators (boolean system) was rarely possible on Internet, in sport medicine or anywhere. But from the beginning of 1997, many search motors on the Net create this possibility, although still with a certain syntax disparity.     

Évaluation d''une batterie de tests pour la sélection des jointeurs d''une firme hydroélectrique

The purpose of this study was to evaluate the specificity, the reliability and the discriminative power of 12 tests that could be used to select electrical utility workers-splicers. The work of electrical utility workers-splicers consists of building, repair and modification of the underground power grid or lines. The first requirement to retain a test was its reliability (standard error of the estimate arbitrarily set to or lower than 12%). With 13 unexperienced subjects, only four tests met that criterion. The remaining original tests, although specific to the task, show very high test-retest variability (SEE = 15.7 to 107.7%) and were thus rejected on that basis alone. The test-retest data also showed a learning process for many of the tests. Theoretically, that would have to be considered when choosing a pass or fail criterion. From a practical point of view, however, the learning process was observed mostly in the agility tests, which were the same as those rejected due to their low reliability. In the second phase of this study, the discriminative power of the tests was established in comparing inexperienced male subjects (n = 13) to experienced male workers (n = 16). Again, significant differences were found for agility tests that were already rejected. For the four reliability tests, with high physical requirements regarding strength or muscular endurance, there was a significant difference for only one test, indicating a lack of discrimination for the other three. As a result, a logical decision would be to reject those tests. However, considering that these tests were “physical” rather than involving “motor abilities”, the experience of the workers did not make any difference. It is important to underline that inexperienced subjects were physically fit physical education students, which may explain why they scored as high as the workers in these tests. In other words, the unexperienced subjects barely passed these tests. Ideally, it would have been preferable to compare poor and good workers but that was not possible due to adminitrative problems. The correlations among test items was determined in order to eliminate tests having high levels of covariance. None of the retained reliability tests were highly correlated but all were retained as valid tests. In general however, this study has shown the difficulties in constructing task-specific tests. Too many of the original tests, mostly “motor abilities” tests, had to be rejected due to low reliability. Other tests would need to be designed and tested again in order to have a complete battery to mimic the essential aspects of this task.     

Modification de la lipolyse du tissu adipeux après un entraînement en endurance chez des sujets obèses

This study investigates the effect of a 3 month endurance training on in vitro adipose tissue lipolysis in 13 obese men (body mass index: 36.9 ± 1.3 kg/m²). Training decreased body fat mass percentage (P < 0.05), without body weight change. Lipolytic effects of epinephrine, isoproterenol (β-adrenoceptor agonist) and dobutamine (β₁-adrenoceptor agonist) were significantly increased (P< 0.05). Antilipolytic effects of α₂-adrenoceptor and insulin were significantly decreased (P < 0.05). Endurance training in obese men enhances adipose tissue lipolysis through β-adrenergic pathway, and decreases antilipolytic activity.     

Augmentation de la fréquence d’apparition de l’hypoxémie induite par l’exercice chez des rameurs de haut-niveau

Objectifs. – Évaluer la fréquence d’apparition de l’hypoxémie induite par l’exercice (HIE) chez un groupe de rameurs de haut-niveau.Méthodes. – Sept rameurs de haut-niveau ont participé à l’étude (19,14 ± 1,3 ans). Les sujets ont effectué une épreuve d’effort à charge croissante sur un rameur ergométrique lors de laquelle les échanges gazeux et la saturation de l’hémoglobine en oxygène (SpO₂) ont été mesurés.Résultats. – Les sujets avaient une VO₂max de 61,68 ± 1,65 ml/min par kilogramme. Tous ont présenté une HIE avec des chutes de SpO₂ comprises entre 5 et 11 %. Cette chute était significative dès 70 % VO₂max. Le volume d’entraînement réduit des athlètes testés par rapport aux autres athlètes endurants semble indiquer que le phénomène est indépendant du volume d’entraînement.Conclusion. – Cette étude a permis de mettre en évidence que 100 % des rameurs de haut-niveau présentaient une HIE. La limitation ventilatoire et l’importante masse musculaire mise en jeu spécifiques à l’aviron seraient les hypothèses explicatives.Aim. – To access the frequency of exercise-induced hypoxemia (EIH) in elite oarsmen.Method. – Seven elite oarsmen participated (19.14 ± 1.3 year) in this study. Subjects performed an incremental exercise testing on a rowing ergometer. Gas exchanges and pulse oxymetric saturation in oxygen (SpO₂) were measured during exercise.Results. – Subjects exhibited a mean of VO₂max of 61.68 ± 1.65 ml min^–1 kg^–1. All rowers showed an EIH with a SpO₂ ranging between 5% and 11%. This SpO₂ fall was significant from 70% VO₂max. The reduced training volume of our athletes compared with others endurance trained athletes seems indicate that phenomenon is not dependent of training volume.Conclusion. – This study showed that 100% of elite oarsmen exhibit EIH. Mechanical limitation in ventilation and great muscle mass involved in rowing could be the explicative hypothesis.     

Taux sériques du propeptide aminoterminal du procollagène III chez des sportifs soumis à un entraînement régulier

Serum Procollagen III N-terminal Propeptide (PIIINP), a marker of bone matrix turnover, was measured in 36 sportsmen undergoing intensive training, including 23 adolescent gymnasts. All values are within the range of control values for age, suggesting that PIIINP is not modified by intensive training.