During periods of intense exercise the adenine nucleotide pool in skeletal muscle becomes partially depleted. Ribose has been shown to increase rates of both purine salvage and adenine nucleotide de novo synthesis in rat skeletal muscle. However, to date no research has been conducted on the effects of ribose on adenine nucleotide levels in human skeletal muscle. Therefore, the purpose of this investigation was to determine the effects of ribose supplementation on adenine nucleotide levels in human skeletal muscle during high-intensity exercise. To do this, an 11-day supplementation of either ribose (20 g.d-1) or placebo (glucose 20 g•d-1) was given to 16 healthy male subjects. After 72 hours of supplementation, the subjects performed five-days of high-intensity exercise designed to elicit significant reductions in adenine nucleotides. A 65 hour recovery period was completed following the exercise protocol. Muscle biopsies were performed at four different time points during the supplementation/exercise period.The exercise protocol elicited significant decreases in skeletal muscle adenine nucleotide levels of both the ribose and placebo groups (p<0.05). However, ribose supplementation was shown to partially attenuated the adenine nucleotide decrease. The placebo group demonstrated a 39% decrease, while the ribose group dropped 23% in TAN levels (p<0.05). The largest decreases were observed in ATP for both groups; however, the decreases were significantly greater in the placebo group (p<0.05). Both groups displayed a similar amount of replenishment in adenine nucleotides 65 hours following the 5-day exercise period. No differences were demonstrated in ADP or AMP for either the ribose and placebo groups throughout the investigation. Both groups displayed an increase in E MP post-exercise, but the increase was only significant in the ribose group (p<0.05). No differences in mean power, peak power, and fatigue were observed between the ribose and placebo group. However, the ribose group consistently displayed a non-significantly greater percent change (3.1 %) in mean power. / School of Physical Education

The purpose of this study was to investigate the effects of ribose supplementation on swimming performance in collegiate male swimmers. Twenty trained collegiate male swimmers (mean ± SE; age: 19.7 ± 0.4 years; height: 182.6 ± 1.2 cm; weight: 75.9 ± 0.6kg) completed three randomly assigned trials; two prior to the supplementation period and one immediately after supplementation. The period between the first and the second trial was used as a control period and all subjects (n=20) participated. During the supplementation period the ribose group (n=10) received 20 g of ribose per day, while the placebo group (n=10) received 20 g of dextrose. The first day involved body composition, swim bench, and swim power measurements. The second day a test set consisting of 15x45.8 m freestyle swimming was performed. A blood sample was obtained from the antecubical vein prior to the swim and 1 minute after the completion of the last repeat. Swimming performance during the test set showed significant improvements for either group from T1 to T3. (mean ± SE 27.44 ± 0.32 and 27.55 ± 0.26 for the ribose and placebo groups respectively at T1). The times at the end of the supplementation period were 27.33 ± 0.28 and 27.36 ± 0.22 seconds. No significantdifferences were reported in swim power or swim bench. Lactate, uric acid, ammonia, and hypoxanthine did not significantly change for either group between the trials. The results from the study suggest that swimming performance does not appear to be enhanced with the supplementation of ribose during exhaustive exercise in collegiate male swimmers. / School of Physical Education