Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans

Abstract

The effect of oral ribose supplementation on the resynthesis of adenine nucleotides and performance after 1 wk of intense intermittent exercise was examined. Eight subjects performed a random double-blind crossover design. The subjects performed cycle training consisting of 15 × 10 s of all-out sprinting twice per day for 7 days. After training the subjects received either ribose (200 mg/kg body wt; Rib) or placebo (Pla) three times per day for 3 days. An exercise test was performed at 72 h after the last training session. Immediately after the last training session, muscle ATP was lowered ( P < 0.05) by 25 ± 2 and 22 ± 3% in Pla and Rib, respectively. In both Pla and Rib, muscle ATP levels at 5 and 24 h after the exercise were still lower ( P < 0.05) than pretraining. After 72 h, muscle ATP was similar ( P > 0.05) to pretraining in Rib (24.6 ± 0.6 vs. 26.2 ± 0.2 mmol/kg dry wt) but still lower ( P < 0.05) in Pla (21.1 ± 0.5 vs. 26.0 ± 0.2 mmol/kg dry wt) and higher ( P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after the test performed at 72 h were higher ( P < 0.05) in Rib compared with Pla. Mean and peak power outputs during the test performed at 72 h were similar ( P > 0.05) in Pla and Rib. The results support the hypothesis that the availability of ribose in the muscle is a limiting factor for the rate of resynthesis of ATP. Furthermore, the reduction in muscle ATP observed after intense training does not appear to be limiting for high-intensity exercise performance.