Glycine-Arginine--Ketoisocaproic Acid Improves Performance of Repeated Cycling Sprints

BUFORD, BRITNI N.; KOCH, ALEXANDER J.

Medicine & Science in Sports & Exercise:
BASIC SCIENCES: Original Investigations
Abstract

BUFORD, B. N., and A. J. KOCH. Glycine-Arginine-α-Ketoisocaproic Acid Improves Performance of Repeated Cycling Sprints. Med. Sci. Sports Exerc., Vol. 36, No. 4, pp. 583–587, 2004.

Purpose: The purpose of this study was to determine the effect of glycine-arginine-α-ketoisocaproic acid (GAKIC) supplementation on repeated bouts of anaerobic cycling performance.

Methods: Ten men completed a randomized, double-blinded, placebo-controlled exercise protocol of two sessions separated by 7 d. Plasma lactate was analyzed in blood collected 45 min before exercise (REST) and 5 min postexercise (POST). Subjects consumed either 11.2-g GAKIC or placebo (PLC) during a 45-min period between the REST and exercise. Mean power, peak power, and fatigue values were assessed from five supramaximal, 10-s cycle ergometer sprints, separated by 1-min rest intervals. Data were analyzed using repeated measures ANCOVA.

Results: A significant treatment × time interaction (P = 0.039) was observed for the change in mean power output over the five sprints between the GAKIC and PLC treatments. Post hoc analyses revealed a greater retention of mean power (P = 0.038) between sprints 1 and 2 after GAKIC (−1 ± 9 W) versus PLC treatment (−47 ± 18 W). No other performance variables differed between PLC and GAKIC. POST lactate was increased (P < 0.001) above REST, but there was no difference between treatments (P = 0.936).

Conclusion: These data support an ergogenic effect of GAKIC for attenuating the decline in mean power during repeated bouts of supramaximal exercise.

Author Information

Health and Exercise Sciences, Truman State University, Kirksville, MO

Address for correspondence: Alexander J. Koch, Ph.D., Health and Sciences Program, Truman State University, 100 East Normal, Kirksville, MO 63501; E-mail: akoch@truman.edu.

Submitted for publication June 2003.

Accepted for publication November 2003.

©2004The American College of Sports Medicine