Time to fatigue on lactate threshold and supplementation with sodium bicarbonate in middle-distance college athletes

Introduction: There have been many researches that have attempted to improve sports performance based on supplementation with different buffer substances. Within this group of substances, sodium bicarbonate supplementation has been widely used in both cyclic and acyclic sports. In the case of cyclic sports, it has been tried to improve the performance of pedestrian races at different percentages of peak oxygen uptake. However, the results on intensity over anaerobic threshold have been contradictory. Objective: To determine the performance variation based on execution in a endurance test after sodium bicarbonate administration. The second aim to evaluate the levels of blood lactate in the finish of endurance test. Material and method: Five college athletes of middle-endurance and endurance race runners were subjects in the study. The variables measured were: effort maximum time (in seconds) measured through a endurance test, and maximum lactate post effort. All athletes were administered sodium bicarbonate (0.3 g•Kg-1 body mass) or a placebo (0.045 g•Kg-1 body mass) an hour before each endurance test. Student's t-test (lactate) and Wilcoxon (time) was used for the statistical analysis. The size of the effect was calculated with Cohen's d-test. Results: The effort maximum time showed a significant increase (P < 0.042; size of the effect = 0.852) as well as lactate concentrations post effort (P < 0.022; size of the effect = 1.987). Conclusions: The results of the study showed that the supplementation whit sodium bicarbonate generates an increase in the performance and lactate concentrations post effort, when the race speed surpass by seven percent the anaerobic threshold speed.