Effets en miroir de l''entraînement et du surentraînement sur la fonction somatotrope et la balance glucidolipidique à l''exerciceEffects out of mirror of the drive and overtraining on the somatotropic function and the glucido-lipidic balance with the exercise

Objective. – To confirm the assumption whereby overtraining would have opposite effects on the utilisation of the substrates and the somatotropic function.Exposed facts. – The drive has different effects according to its characteristics and its level. It seems y to have two types of drive: that which amplify the aptitude to oxidize lipids (low powers) and that which accroit the aptitude to oxidize glucides (high powers and/or intermittent exercise). Overtraining reverses these two effects. The somatotropic axis has an evolution parallel with these processes and seems implied in those.Conclusion. – This diagram deserves to be confirmed by additional studies.     

Intérêt du questionnaire de surentraînement de la Société française de médecine du sport lors d’un suivi de sportifsOvertraining questionnaire of Société française de médecine du sport for a continuous observation in a sport population

Aim. – Verify the sensibility of a standardised overtraining questionnaire during a weekly observation in a sport population.Methods and results. – The experiment was carried out in 12 athletes, 20–23 years old, students at the University in Licence STAPS, with a standardised overtraining questionnaire given every week during 8 weeks. Results were analysed individually and for the total population. Those showed that overtraining questionnaire could allow individualised training programs, and could provide some pertinent information on sleep quality and physical condition for each athlete. For the coach, the overtraining questionnaire permits to identify some fatigue state, consecutively to training variations. On the total population, the analysis of overtraining questionnaire showed some items more reliable than other.Conclusion. – This questionnaire was very interesting for coaches, allowing a good individualisation of the training program. Nevertheless, this questionnaire presents intricate statistical analysis when given at high frequency.     

L''hémorhéologie permet-elle de comprendre le « paradoxe de l''hématocrite » lors de l’entraînement et du surentraînement ?Does hemorheology explain the paradox of hematocrit in training and overtraining?

Purpose. – Doping with EPO increases both hematocrit and performance. On the opposite, training reduces hematocrit due to plasma volume extension and overtraining both increases hematocrit and decreases performance. This apparent paradox seems to be explained by a new concept proposed interpreting the interactions between viscosity factors and blood flow.Facts. – Viscosity factors exert a non linear “all or none” effect that can be described according to the “ percolation theory”. Blood viscosity has no hemodynamic relevance by its own, but viscosity factors (hematocrit, red cell deformability and aggregability, plasma viscosity) can result according to flow conditions in self-potentiating phenomena of quick transition between a state of high fluidity and a state of red cell aggregate clumping. In muscle, this model predicts that: (a) during exercise the only viscosity factor that could influence flow is plasma viscosity; (b) at rest all viscosity factors (including high hematocrit) may induce a self-potentiating “viscidation” process.Conclusion. – According to these concepts, supraphysiologic hematocrit values are probably unable to disturb muscular perfusion at exercise, but are likely to promote self-potentiated stasis at rest and thus to increase the risk of thrombosis.     

Le questionnaire de surentraînement de la Société française de médecine du sport : reproductibilité à court termeOvertraining questionnaire of the Société française de médecine du sport (French Society of Sport Medicine): short term reproducibility

Purpose. – To assess the short-term stability, over time, of a slightly modified version of the overtraining questionnaire proposed by the SFMS.Methods. – Three or 7-day test–retest of the questionnaire was completed in 30 high level athletes. In a first stage analysis, the score obtained during the first test was compared to and correlated with that obtained during the second one. Then, in a second stage analysis, the individual reproducibility of each item was assessed using a similitude index: a value of 100% meant that all the athletes gave an identical response for the two trials.Results. – Scores were not different between the two tests and intra-class correlation coefficients were r = 0.82. Overall reproducibility of the similitude index was quite good even if six items of 52 displayed a lower similitude index (around 80%).Conclusion. – The short-term reproducibility of the overtraining questionnaire is quite good. This result reinforces its reliability and warrants its use in a longitudinal follow-up framework aimed to detect precociously an overtraining syndrome.     

Suivi de l’entraînement de nageurs de haut niveau par questionnaire de fatigue, dosages hormonaux et variabilité de la fréquence cardiaqueTraining follow up by questionnaire fatigue, hormones and heart rate variability measurements

Introduction. – A short questionnaire of fatigue, urinary cortisol/cortisone ratio and heart rate variability were measured in 14 elite swimmers during heavy, light and moderate training periods.Results. – The questionnaire was strongly related to the variations of training and performance (r > 0.70). Correlations were lower with the hormonal ratio and insignificant with the heart rate variability.Conclusion. – The questionnaire and the hormonal ratio were good markers of the variations of training and performance contrary to the heart rate variability.     

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.     

Le « syndrome des jambes lourdes » chez les athlètes surentraînés est-il le reflet de désordres hémorhéologiques ?Is the feeling of heavy legs in overtrained athletes related to impaired hemorheology?

Introduction. – The aim of this work is to evaluate if the feeling of heavy legs in athletes is correlated with overtraining syndrome-related hemorheological disturbances.Results. – The subjects who quoted the item: “I have the feeling of heavy legs” had higher plasma viscosity and higher red cell aggregation parameters. The overtraining score was correlated positively with plasma viscosity, and aggregability parameters. The feeling of heavy legs was correlated with plasma viscosity and aggregability.Conclusion. – These findings suggest that the feeling of heavy legs in overtrained athletes is related to overtraining syndrome-related hemorheologic disturbances, namely mild plasma hyperviscosity and mild erythrocyte hyperaggregability.     

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.     

Activité physique et remodelage osseux : étude chez une population de jeunes gymnastesPhysical exercise and bone turnover: a study in young girl gymnasts

Aims – Intensive exercise is known to improve the bone mass acquisition. One of the main explanations consists in the mechanical strains exerted on the skeleton. Little is known about the effects of physical exercise on the bone remodelling process.Methods and results – The bone remodelling rate evaluated in a group of young female (24 gymnasts and 21 controls), using a bone resorption marker, the CrossLaps peptides CTx. We measured in our subjects the bone mineral density at the whole body and at six regional sites. The bone density was statistically higher in the gymnasts compared to the controls at all the specific sites. The CTx level corrected by urinary creatinine was significantly higher in the gymnasts, reflecting a faster bone remodelling rate.Conclusion – Intensive physical activity could improve the bone mineral acquisition probably by a stimulation of the bone remodelling activity.     

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.     

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.     

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.     

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.     

Adaptations mécaniques et neurophysiologiques induites par la sollicitation musculaire excentrique : l''effet protecteur

Objectifs. – Présenter la notion d'effet protecteur induit par la sollicitation musculaire excentrique et aborder les différents types d'adaptations pouvant rendre compte de ce phénomène.Actualités. – La réponse du complexe neuromusculaire à une séance de renforcement musculaire excentrique est conditionnée par le type de sollicitation réalisée au préalable. Les dommages musculaires sont en effet moins marqués et la récupération de la contractilité musculaire plus rapide si des sollicitations excentriques sont effectuées quelques jours à plusieurs mois avant la séance.Conclusion. – L'effet protecteur semble préférentiellement résulter d'une adaptation du tissu contractile à la contrainte mécanique. La prise en compte de l'effet protecteur doit permettre d'optimiser la programmation de l'entraînement de la force et de la rééducation fonctionnelle.Objectives. – To present the eccentric contraction-induced protective effect, as well as the different kind of adaptations possibly involved in this phenomenon.Topics. – The effects of an eccentric exercise session on the neuromuscular system depend on the contraction type performed previously. A repeated eccentric exercise does not induce the same negative effects on force production capacity than a first bout. Indeed, strength recovery is improved and eccentric exercise-induced ultrastructural damages are less pronounced after a second exercise bout performed 5 days to 6 months after the first one.Conclusion. – The protective effect seems to be mainly related to contractile adaptations to eccentric muscular solicitation. Strength training and rehabilitation programs could be improved by taking into account this protective effect.     

Réponses corticotropes à un stress intense en fonction de l'entraînement chez deux souches de rats. Résultats préliminairesCorticotropic responses to acute stress according to exercise training in different rat strains: preliminary results

Aims – Determine the corticotropic responses to acute stress with or without prior exercise training and following the corticotropic phenotype of the rats.Methods and results – Lewis and SHR strains were selected for their opposite corticotropic responsiveness characteristics (high and low in SHR and Lewis strain, respectively). This study shows that exercise training induces opposite adrenal responses in SHR strain and in Lewis strain (which decrease increase its corticosterone concentration, respectively).Conclusion – This suggests that genetic may play an key role in pituitary-adrenal adaptations to exercise training.     

Adaptations myocardiques chez l'enfant prépubère soumis à un entraînement intensif. Étude comparative entre une population de gymnastes et de nageurs

Introduction. The purpose of the present study was to investigate the cardiac structure and function in prepubertal highly-trained swimmers and gymnasts. Method. Thirty-five children (10–11 years) were investigated: nine swimmers (S), 15 gymnasts (G) and 11 as a control group (C). The swimmers and gymnasts had trained on average 10 to 12 h/wk for at least 2 years. The subjects were examined at rest by M-mode, bi-dimensional and Doppler analyses according to standard procedures recommended by the American Society of Echocardiography. The following parameters were obtained: left ventricular (LV) internal dimension at end-diastole (LVIDd) and at end-systole —posterior wall and interventricular septal thicknesses -Left ventricular mass (Lvmass) — LV shortening fraction — ejection fraction — peak velocity of early diastolic rapid inflow and of atrial contraction filling — mitral acceleration and deceleration — isovolumic relaxation time. In addition, the cardiac output was evaluated from transaortic Doppler examinations. The heart rate (Hr) was measured simultaneously with all echocardiographic examinations. Results.- The main results show that LV internal diastolic dimensions and LV mass were significantly higher in S than in the other two groups. No differences were however observed between groups regarding cardiac wall thicknesses. Moreover, all values of G were very close to those obtained by C. Both systolic and diastolic functions were normal in the three groups. Finally, the stroke volume (SV) was higher in S than in the other two groups and because of a bradycardia observed among S, the resting cardiac output was similar in the three groups. The higher LVIDd in S still persisted after correction for Hr. A low diastolic period associated with higher LVIDs can probably explain the high SV in S. Conclusion.- Our results strongly suggest that cardiac structure and function adaptations can occur in prepubertal children as a result of an intensive training program prolonged over a long-term period, only if this program is predominantly based on aerobic exercises. Whatever the kind of sport, neither LV systolic nor diastolic functions are affected by training during prepuberty. Further investigations will however be needed in order to better understand diastolic function adaptations to intensive aerobic training in children.     

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.     

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.