Comparaison de performances aérobies et anaérobies au cours d'exercices locaux et généraux

Purpose – The relationships between the aerobic and anaerobic abilities for local and general exercises has been studied in twenty three subjects.Methods – Maximal aerobic power (PMA), the lactate level corresponding to 4 mmol l⁻¹ (Pla4) and maximal anaerobic power on a Monark cycle ergometer (general exercises) have been correlated with aerobic and anaerobic performances for knee extension exercises (local exercises). Maximal anaerobic power (Pmax) has been determined by means of a force–velocity test on the same Monark ergometer. Two indices of local aerobic ability were estimated: 1) the peak power (Ppic) measured at the end of an incremental knee extension exercise, 2) the knee extension critical power (PC) calculated as equal to the slope of the relationship between exhaustion time and total work performed during three exhaustives exercises at constant load. Maximal anaerobic power of the knee extensors was determined by measuring the maximal power at an angular velocitie of 240° s⁻¹ (Pbiodex) with an isokinetic ergometer.Results – The correlations between all the indices of local and general aerobic abilities were highly significant (0.82<r<0.96; p<0.001) whatever the expression of the data (absolute values or related to the quadriceps muscle mass). The relationship between PC and Pla4 was significant even when these variables were expressed as fractions of the maximal aerobic power (PC/Ppic and Pla4%: r=0.75; p<0.001). Similarly, Pmax and Pbiodex were correlated even when related to quadriceps muscle mass (r=0.60; p<0.01). In contrast to Pmax, Pbiodex was negatively correlated with the local and general aerobic indices, but only when these variables was related to quadriceps muscle mass (0.44<r<0.63; p<0.05).Conclusions – The general aerobic abilities are very well correlated with the local aerobic abilities. Moreover, the correlation between PC/Ppic and Pla4% suggests that local and the general endurances are partially linked. The best indices of maximal anaerobic power and local anaerobic power are observed in the same subjects. In contrast, the best local and general aerobic indices are observed in the subjects presenting the weakest indices of anaerobic power.     

Réponses du cortisol et de la testostérone salivaires au cours de la récupération post-compétitive en rugby

Aim. – In order to evaluate the biological repercussions of the post-competitive tiredness state, we measured the progress of the salivary cortisol and testosterone levels in the players of a rugby-team during the week following an international match.Results. – The results reveal a fall of the cortisol levels during the first 4 days following the competition, compared to the values measured at the same hour of a resting day. Conversely, the testosterone levels present an increase during the same period. Consequently, 5 days of recovery are needed for these two biological variables chosen as tiredness markers to return to their basic values.     

Variation de l'amplitude de l'onde T au cours de l'exercice et pendant la récupération chez des sportifs entraînés

Aims. – To study T-wave amplitude changes during exercise and recovery in trained athletes.Methods and results. – Thirty two athletes of both sexes underwent an incremental cycle test. Cardiac electric activity (ECG) was recorded every minute during exercise and the following five minutes of recovery. T-wave amplitude was manually measured on V5 ECG complex enlarged 4-fold. The statistical analysis was done using two factor's Anova. The results showed that T-wave amplitude 1) increased significantly during the three first minutes of the recovery, 2) was not linked to T-wave decrease or increase during previous exercise, and 3) was significantly lower in females than in males. Pathophysiological mechanisms of this ECG repolarisation in athletes during recovery following exercise remains unclear.     

Estimation de la contribution énergétique d'origine aérobie et anaérobie et de sa répartition au cours d'un 800 m couru sur le mode compétition

Aim – Determine the part of each energetic system at different times of 800m competition. Oxygen uptake and speed were recorded continuously.Materials and methods – Five athletes performed on an outdoor track a test to determine the maximal oxygen uptake and the maximal aerobic speed and a supramaximal exercise of 800m.Results – The overall energetic expenditure as well as the oxygen deficit assessed at 31.9% were almost identical at those obtained during an 800m race running on a treadmill. Only the repartition of the oxygen deficit notably differed during the race. This suggered that the kinetic of the speed had a determining incidence on the anaerobic contribution as well as aerobic contribution when there were changes in running velocity.     

Corrélations entre scores au questionnaire de la Société française de médecine du sport et concentrations de cortisol et testostérone salivaires lors du suivi d’une équipe de rugby de haut niveau

Objective. – To carry out the follow-up of 21 high level rugby players by means of the psycho-comportmental questionnaire of the “French Society of Sports Medicine” (SFMS), of the salivary testosterone (T) and cortisol (C) levels and of their ratio T/C during the sporting season.Materials and methods. – The players provided three samples of saliva, at awakening (8 am), just before the lunch (11 am), and at 17 pm in order to assay cortisol and testosterone. The first measurements were done at the beginning of season (T1), 12 weeks (T2) and 24 weeks (T3) after T1. At the same periods, they completed the 54 items of the SFMS questionnaire which allows to give a score (from 1 to 54) proportional to the state of tiredness of the subject. The performance of the team was estimated from the ratio of victories to the number of matches played over the season.Results and discussion. – The increase in the score obtained with the SFMS questionnaire and the variations of the hormonal levels during the season seem to reflect a normal adaptation phenomenon to the training load, a fact which is confirmed by the maintenance of the same level of performance of the team throughout the season. This study permitted to highlight the parallel evolutions between the psycho-comportemental index (score) and the hormonal markers of the state of tiredness. Thus, it appears that the SFMS questionnaire is an interesting and easy to employ tool to evaluate the state of tiredness (or reciprocally of form) of a sportsman during the course of the sporting season.     

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.     

Effets de l'entraı&#x0302;nement 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.