EFFECT OF CREATINE AND RECOVERY TIME ON POWER OUTPUT DURING 45 SECOND SUPRAMAXIMAL CYCLING INTERVALS

Abstract

We examined the effect of creatine (Cr) supplementation and recovery time on power output during four, 45 s bouts of supramaximal cycling. Methods: 14 trained male cyclists, randomly divided into a creatine or placebo group, ingested 25 g per day of Cr or placebo for 5 day and 5 g per day thereafter until testing was completed. A double blind protocol was used. Subjects completed a Wingate, a VO2max, and three recovery tests, each on a mechanically braked cycle ergometer and separated by at least 48 h. The recovery tests consisted of four, 45 s supramaximal intervals separated by 45, 90, or 135 s of active recovery; a random order was used. Load was 5.5 and 2.5 percent of body mass for the intervals and active rest, respectively. Mean and peak power, VO2, HR, blood lactate, and percent fatigue within each 45 s work bout and across bouts 1 and 4 were measured during the intervals. Creatinine excretion and lean body mass (LBM) were also measured pre- to post-intervention. Results: There was no significant difference in LBM, mean and peak power output, HR, VO2, and percent fatigue across the work bouts or between groups and recovery periods. Cr supplementation significantly lowered blood lactate concentration after bout 2 in the 45 s recovery test and increased creatinine excretion (p < .05). Conclusion: Cr supplementation did not alter mean or peak power output during four, 45 s supramaximal cycling bouts that were separated by 45, 90, or 135 s of active recovery.