Abstract
Aim: The purpose of this study was to study changes in gross efficiency of locomotion after a prolonged trail running race (3000 m up and 300 m down). The second purpose was to investigate the effectiveness of supplementation in vitamin on gross efficiency variability.Materials and methods: Twenty-two well-trained endurance runners took part in this study. They had to perform four sub maximal tests before, 24, 48 and 72 hours after the race in order to estimate gross efficiency of locomotion and a maximal contraction test in the same period. They were divided in two groups either with supplementation (Isoxan Endurance ®) or without (placebo).Results: In both groups we have observed a decrease in gross efficiency 24 and 48 hours after the race (respectively before and 24 hours after: 20.02 ± 0.2 vs 19.4 ± 0.1%, P < 0.05) and a decrease in Maximal Voluntary Force. Within this framework these alterations were significa-tively less important in the group with supplementation.Conclusion: Results of this study confirm the classically observed decrease in efficiency during prolonged exercise. In our study supple-mentation in vitamin (according to the recommended daily allowances) are associated with a less important decrease in efficiency and maximal force suggesting a possible effect of supplementation on muscular function. Further works are necessary to validate this hypothesis especially after eccentric contractions.