Date of Award

1995

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology

First Advisor

Arnold G. Nelson

Abstract

The effects of creatine supplementation on endurance and metabolism during high intensity intermittent exercise was examined using 18 males and females (age 19-26). The subjects were randomly divided into 2 groups (creatine and placebo) and the testing proceeded in two phases. During phase 1 both groups received a placebo. During phase 2 the placebo group again received a placebo, while the creatine group received creatine. Testing consisted of a several high intensity intermittent cycling protocols on a stationary cycle ergometer. Both groups performed all test bouts (in random order) in phase 1 and again in phase 2. Testing consisted of: Continuous (Bout A)--Continuos pedaling at 150% VO2 peak until exhaustion. 30/60 (Bout B)--30 seconds of pedaling at 150% VO2 peak followed by 60 seconds rest, repeated until exhaustion. 20/40 (Bout C)--20 seconds pedaling at 150% VO2 peak followed by 40 seconds rest, repeated until exhaustion. 10/20 (Bout D)--10 seconds pedaling at 150% VO2 peak followed by 20 seconds rest, repeated until exhaustion. The placebo group showed no significant change in time to exhaustion from phase 1 to phase 2 for any of the bouts tested. The creatine group, however, showed a significant increase in time to exhaustion on all bouts. Bout D was impacted significantly pedaling at 150% VO2 peak followed by 20 seconds rest, repeated until exhaustion. The placebo group showed no significant change in time to exhaustion from phase 1 to phase 2 for any of the bouts tested. The creatine group, however, showed a significant increase in time to exhaustion on all bouts. Bout D was impacted significantly more than the other bouts with a more than twofold increase in time to exhaustion. (note that bout D was truncated before subjects reached exhaustion because even at twice the performance time of phase 1 subjects reported feeling very little fatigue and the ability to continue indefinitely). Oxygen consumption showed no change from phase 1 to phase 2 for the placebo group, while the creatine group showed a significantly lower rate of oxygen consumption on bouts D and C. Blood lactic acid values were also lower on bouts C and D for the creatine group only. Creatine supplementation also led to significantly increased urinary creatinine concentrations. Therefore creatine supplementation significantly impacted performance of high intensity intermittent exercise.

Pages

116

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