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.     

Influence des caractéristiques de la natation sur la performance lors d’un enchaînement natation–cyclisme

Purpose. – Investigate the influence of previous swimming on energy expenditure during the subsequent cycling exercise of a triathlon.Methods. – Ten well trained triathletes underwent 3 swim-to-cycle transitions and 1 isolated cycling trial (C trial). The cycling exercises consisted in 15 min on a bicycle ergometer at a power output corresponding to the ventilatory threshold +5 %. During the transitions, this exercise was preceded by swimming bouts soliciting different muscles, undertaken at a 750 m competition pace for the same duration (swimming with arms and legs: Sal trial, with arms only: SA trial, or with legs only: SL trial).Résultats. – The swimming bouts of SA and Sal trials involved a significant increase in energy expenditure during subsequent cycling in comparison with isolated cycling (P < 0.05). Moreover, cycling efficiency was not significantly different between SA and SAL trials (P > 0.05).Conclusion. – A short intense swimming leads to an increase in energy expenditure during subsequent cycling, because of the thermoregulatory adjustments and the additional oxygen cost of respiratory work involved during swimming. It also shows that physiological adaptation during cycling does not depend on the lower limb work during prior swimming.     

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.     

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.