Abstract des Autors

Our purpose was to test the significance of exhaustive training in aerobic or endurance capacity. The extent of adaptations to endurance training was evaluated by assessing the increase in physical performance capability and oxidative markers in the organs of rats trained by various exercise programs. Rats were trained by treadmill running 5 days/week at 30 m/min for 8 weeks by one of three protocols: T1: 60 min/day; T2 120 min/day; and T3 120 min/day (3 day/week) and to exhaustion (2 days/week). Groups T2 and T3 ran for longer than T1 in an endurance exercise test, in which the animals ran at 30 m/min to exhaustion; no difference was observed between groups T2 and T3. All 3 trained groups showed a similar increase (20-27) in the fast-twitch oxidativeglycolytic (FOG) fibers with a concomitant decrease in the fast-twitch glycolytic (FG) fiber population in gastrocnemius. The capillary supply in gastrocnemius increased with the duration of exercise: no difference was found between groups T2 and T3. Likewise, no distinction was seen between groups T2 and T3 in the increase in succinate dehydrogenase activity in gastrocnemius and the heart. These results suggest that the maximal adaptive response to endurance training does not require daily exhaustive exercise.