No effects of oral ribose supplementation on repeated maximal exercise andde novo ATP resynthesis

A double-blind randomized study was performed to evaluate the effect of ora l ribose supplementation on repeated maximal exercise and ATP recovery afte r intermittent maximal muscle contractions. Muscle power output was measure d during dynamic knee extensions with the right leg on an isokinetic dynamo meter before (pretest) and after (posttest) a 6-day training period in conj unction with ribose (R, 4 doses/day at 4 g/dose, n = 10) or placebo (P, n = 9) intake. The exercise protocol consisted of two bouts (A and B) of maxim al contractions, separated by 15 s of rest. Bouts A and B consisted of 15 s eries of 12 contractions each, separated by a 60-min rest period. During th e training period, the subjects performed the same exercise protocol twice per day, with 3-5 h of rest between exercise sessions. Blood samples were c ollected before and after bouts A and B and 24 h after bout B. Knee-extensi on power outputs were similar to 10% higher in the posttest than in the pre test but were similar between P and R for all contraction series. The exerc ise increased blood lactate and plasma ammonia concentrations (P< 0.05), wi th no significant differences between P and R at any time. After a 6-wk was hout period, in a subgroup of subjects (n = 8), needle-biopsy samples were taken from the vastus lateralis before, immediately after, and 24 h after a n exercise bout similar to the pretest. ATP and total adenine nucleotide co ntent were decreased by <similar to>25 and 20% immediately after and 24 h a fter exercise in P and R. Oral ribose supplementation with 4-g doses four t imes a day does not beneficially impact on postexercise muscle ATP recovery and maximal intermittent exercise performance.