Effets de l'entraı̂nement sur les potentiels aérobie et anaérobie de jeunes nageurs. Exercice réalisé avec les bras

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.     

Un test de terrain simple pour la détermination du seuil anaérobie

Aim – Validate a simple and indirect methodology which supplies a reliable estimate of the run velocity correspondent to the anaerobic threshold.Materials and methods – Twelve subjects took part to this study and each subject was asked to perform a maximum test on 1000, 1500, 2000 and 3000 m. For each athlete was calculate the straight line which joins the values of run tests on 1000 and 1500 and the values on the run tests on 2000 and 3000 m, moreover, the linear regression line interpolating the run values of the 4 tests was calculated. The value of the equation coefficient b of the 2 straight lines and of the regression line was considered the value correspondent to the velocity of the anaerobic threshold. Then each athlete was asked to perform 20 min of continuous run at the 3 various run velocities previously calculated. During the tests previously mentioned the production of haematic lactate was analysed.Results – The 2000 and 3000 m distances are the most suitable to determine the velocity of the anaerobic threshold.     

Les bases génétiques et moléculaires de la performance et de l'adaptation à l'exercice physique

Objectives – This paper reviews the state of our knowledge on the genetic and molecular bases of performance and the response to exercise training, the theme of the inaugural conference of the XIXth annual meeting of the Société Française de Médecine du Sport held in Rennes in October 1999.Topics – The studies on the genetic bases of performance performed over the past 20 years suggest that 25 to 50% of interindividual differences observed in maximal and sub-maximal oxygen consumption as well as in other indicators of aerobic performance could be explained by genetic factors. For metabolic and histochemical properties of skeletal muscle, heritabilities ranging from 40 to 70% have been reported. Considerable interindividual differences are also observed in the cardiorespiratory, metabolic and morphologic adaptations to exercise training and results from twin and family studies suggest that these differences are also determined by genetic factors. Unlike many other complex traits such as hypertension or obesity, the search for candidate genes of performance is in its infancy. Only a few studies with candidate genes such as the angiotensin converting enzyme (ACE), the muscle specific creatine kinase (CKMM) or genes of mitochondrial DNA have reported positive results with indicators of aerobic performance.Conclusion – More studies are needed before any conclusion could be made about the role of these genes in performance and adaptation to exercise training. Although the molecular dissection of performance and adaptation to regular exercise is a complex task, considerable progress will probably be achieved in the next decade in our understanding of the molecular basis of these complex phenotypes.     

Cinétique du cortisol et de l'hormone de croissance plasmatiques lors de deux épreuves sous-maximales avec et sans récupération

Introduction – The purpose of this study is to evaluate cortisol and growth hormone kinetics in plasma during a sub-maximal exercise with and without recovery.Results – There is a significant difference of cortisol and growth hormone kinetics between the two tests. The cortisol concentration increased significantly during exercise without recovery period, the changes of plasmatic cortisol were not significant during exercise with recovery. Plasmatic growth hormone increases after exercise without recovery.Conclusion – The absence of recovery period contributes to increase considerably the level of cortisol and growth hormone in plasma and decreases probably anabolic process in post exercise period.     

Évolution de la puissance maximale anaérobie au cours de la croissance chez le footballeur

Purpose – The aim of the study was to assess the improvement in Maximal Anaerobic Power (PMAna) from two tests in soccer players during growth.Methods – The experiment was carried out in 328 players, 11–18 years old, during their stay at the Clairefontaine National Soccer Center. PMAna was measured from the last 10 meters of the a 40 m-sprint test (ST) and a jump test (JT). The skeletal age (AO) is used as reference, and not the chronological one.Results – The results of the two tests are highly correlated (r= 0.8–0.9), PMAna values being always higher in the ST than in the JT.The most significant increase in PMAna occurs between 13 and 14 years AO (+47% for the ST, +27% for the JT), remains still significant up to 16 AO (respectively +38% and +24% between 14 and 16 AO), but the maximum value is reached at 17 AO. Between 12 and 16 AO, the PMAna value is multiplied by 2.29 for the ST and 1.81 for the JT.Conclusions – Sprint and jump tests seem well adapted to estimate PMAna in soccer players. The measure of the skeletal age during growth is needed for a better interpretation of the results. In addition, results obtained during growth allow a reliable estimation of PMAna in adulthood.     

Dopage et sport : connaissances et attitudes des pharmaciens de la ville de Yaoundé

Introduction – Fourty-one retail pharmacists (23 females and 18 males) out of 70 that Yaoundé town counts, participated to this study aimed at determining their attitudes towards and knowledge in doping. They answered a questionnaire concerning their knowledge of doping agents, how they face doping and the role of pharmacists in doping prevention.Synthesis – Results suggest that pharmacists (54%) have been confronted to doping, less than once a month for 27% of them and at least once a month for the rest. Six pharmacists (15%) have been offered to provide doping agents to sport men. 51% (mainly females) consider that the use of food supplements could induce consumption of forbidden drugs. The majority (83%) of pharmacists (mainly females) consider that doping is a public health problem. They agree (88%) that pharmacists have a part to play in doping prevention but also agree (58%; mainly females) that they are poorly or very poorly informed to that effect.Conclusion – The requests made to pharmacists suggest the consumption of doping agents by sport men in our region. It is therefore necessary to carry out an epidemiologic study on prevalence and consumption patterns.     

Médicaments et performance de la fonction d'équilibration

Introduction – Balance control in some sports discipline can be the aim of the action, and its breaking off can expose to severe trauma.Synthesis of facts – Some drugs' adverse effects can induce lower equilibrium performance, in relation for example with vigilance drop or vestibular ototoxicity. The drug effect site can concern one or more links in the chain (peripheral or central impact). Individual sensitivity is variable, as well as speed of reversibility.Conclusion – Symptoms induced by pathology for which therapy is prescribed are sometimes difficult to distinguish from those induced by therapy itself.     

Répercussion de l’asthme induit par l’exercice sur la performance aérobie de l’enfant

Introduction. – Exercise-induced asthma is a clinical syndrome leading to a transient narrowing of the airways after the end of the exercise.Synthesis of results. – In order to observe its effect on aerobic performance 60 prepubescent children including 36 asthmatics have achieved a maximal increased exercise and a 8min constant exercise. The maximal expiratory flow-volume significantly decreased after the 2nd exercise in the exercise-induced asthma children. This means that airways were narrowing with exercise intensity. These narrowing did not seem to have any effect on the aerobic parameters measured in our study.Conclusion. – We conclude that controlled asthma does not limit the aerobic performance in prepubescent children.