Casey, A., Constantin-Teodosiu, C., Howell, S., Hultman, E., & Greenhaff, P. L. (1996). Creatine ingestion favorably affects performance muscle metabolism during maximal exercise in humans. American Journal of Physiology, 271, E31-E37.

Males (N = 9) performed two bouts of 30-s maximal isokinetic cycling before and after ingestion of 20 gm/day of creatine monohydrate (Cr) for five days.

Muscle creatine increased as did the total work (~4%) in both exercise tasks. Work increases were positively correlated with the increase in muscle TCr. Cumulative loss of ATP was less after CR ingestion despite the increase in work production. Resting phosphocreatine (PCr) increased in both type I and II fibers.

Results suggested that improvements in performance were mediated via improved ATP resynthesis as a consequence of increased PCr availability in type II fibers.

Implication. Five days of creatine monohydrate ingestion improved two repeated 30-s bouts of maximal cycling exercise.

Return to Table of Contents for this issue.