EFFECT OF INOSINE SUPPLEMENTATION ON AEROBIC AND ANAEROBIC CYCLING PERFORMANCE

Ten competitive male cyclists completed a Wingate Bike Test (WIN), a 3 0-min self-paced cycling performance bout (END), and a constant load, supramaximal cycling sprint (SPN) to fatigue following 5 d of oral sup plementation (5,000 mg . day(-1)) with inosine and placebo. Blood samp les were obtained prior to and following both supplementation periods, and following each cycling test. Uric acid concentration was higher ( P < 0.05) following supplementation with inosine versus placebo, but 2 ,3-DPG concentration was not changed. The data from WIN demonstrate th at there were no significant differences in peak power (8.5 +/- 0.3 vs 8.4 +/- 0.3 W . kg body mass(-1)), end power (7.0 +/- 0.3 vs 6.9 +/- 0.2 W . kg body mass(-1)), fatigue index (18 +/- 2 vs 18 +/- 2%), tota l work completed (0.45 +/- 0.02 vs 0.45 +/- 0.02 kJ . kg body mass(-1) . 30-s(-1)), and post-test lactate (12.2 +/- 0.5 vs 12.9 +/- 0.6 mmol . l(-1)) between the inosine and placebo trials, respectively. No diff erence was present in the total amount of work completed (6.1 +/- 0.3 vs 6.0 +/- 0.3 kJ . kg body mass(-1)) or post-test lactate (8.4 +/- 1. 0 vs 9.9 +/- 1.3 mmol . l(-1)) during END between the inosine and plac ebo trials, respectively. Time to fatigue was longer (P < 0.05) during SPN for the placebo (109.7 +/- 5.6 s) versus the inosine (99.7 +/- 6. 9 s) trial, but post-test lactate (14.8 +/- 0.7 vs 14.6 +/- 0.8 mmol . l(-1)) was not different between the treatments, respectively. These findings demonstrate that prolonged inosine supplementation does not a ppear to improve aerobic performance and short-term power production d uring cycling and may actually have an ergolytic effect under some tes t conditions.