Effet de l'intensité de l'entraînement sur les réponses en catécholamines à l'exercice supramaximal chez des endurants de sexe masculin

Introduction – In this study we compared catecholamine responses to the Wingate-test in 2 male endurance trained groups: 6 middle distance runners (DFC) (800m and 1500m) and 6 long distance runners (DFL) (5000 m and 10,000 m).Results – As expected DFL exibited higher maximal oxygen consumption (72 ± 2,5 vs 79 ± 4,5 ml min^–1kg ^–1 fat free mass respectively for DFC and DFL) and DFC exibited higher performances during the Wingate-test (15,8 ± 0,3 vs 14,7 ± 0,4 W kg^–1 fat free mass respectively for DFC and DFL). In opposite differences between maximal catecholamine responses (Adrénaline: 3,8 ± 0,7 vs 3,5 ± 0,3 nmol l^–1. Noradrénaline: 20,4 ± 1,5 vs 16 ± 2,1 nmol l^–1 respectively for DFC and DFL) and maximal plasma lactate were not significant.Conclusion – This results suggests that endurance specificity may not induce different catecholamines responses to sprint exercise.     

Effet de l'entraînement sur la désaturation de l'oxyhémoglobine au cours d'une saison sportive chez le triathlète

Introduction – Endurance athletes frequently present an exercise induced hypoxemia at sub-maximal or maximal exercise.Methods – The results of a recent study that compared two groups of highly trained athletes, one with exercise induced hypoxemia and the other without, suggested that a difference in training volume (4 hours per week) and/or training intensity may explain the difference in the exercise-induced hypoxemia observed. The aim of the study was to evaluate the effects of volume and/or intensity of training on exercise induced desaturation in triathletes during a competitive season.Conclusions – This study showed that exercise induced desaturation was related to both volume and intensity of training in triathletes.     

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.     

Adaptations métaboliques à l'entraînement en début de saison de natation. Différences en fonction du sexe

Purpose – In this study, we compared the early metabolic adaptations to swim training between healthy men (n = 7) and women (n = 8).Methods – On the 1^st, 3^rd and 5^th testing sessions, plasma Fourier-transform infrared (FT-IR) spectra were obtained at the resting state and after each standardized testing session.Results – At the 1^st testing session, glycemia decreased more in females than in males (respectively, –1.101, –0.687 mmol.l^–1), triglycerides (TG) increased in females (0.184 mmol/l) and decreased in males (–0.094 mmol.l^–1) and males presented a higher plasma urea increase (p < 0.05). At the third testing session, glycemia increased in females (0.458 mmol.l^–1) whereas it decreased in males (–0.601 mmol.l^–1). Plasma urea increased more in males compared to females during exercise (p < 0.01). On the other hand, Apo B increased in females (0.063 g.l) and decreased in males (–0.073 g.l^–1) during exercise. At the 5^th testing session, males and females exhibited an equivalent metabolic response to exercise. However, IgA, IgG₁, IgG₃ and IgM were significantly different during exercise in males and females (p < 0.01) throughout the three sessions.Conclusions – Indeed, although metabolic adaptations to early phases of swim training were different, male and female subjects finally exhibited the same global metabolic response to endurance exercise. However immunity response to exercise in women and men was different throughout the three testing sessions.     

Dissociation de la réponse du système adrénergique à l'exercice après un repas hyperglucidique et ses conséquences sur la mobilisation des lipides

Aims – Evaluate hyperglucidic meal effect on changes of catecholamines concentrations and on lipids mobilization during exercise.Methods and results – During exercise (one hour at 50% of VO_2max), the adrenaline concentrations increased twice more in fed men than in fast men, whereas no difference was shown for noradrenaline. The exercise-induced increase in lipolysis was similar whatever the nutritional state of subjects (fed or fasted).Conclusion – In fed men, important increase of adrenaline concentrations during exercise counteracted antilipolytic effect of insulin wich occured after ingestion of hyperglucidic meal.