Effect of a carbohydrate and branched-chain amino acid beverage on skill performance in soccer players

The present studies investigated the effect of a carbohydrate and branched-chain amino acid (CHO + BCAA) beverage on cognitive and sport specific skill perfbrmance in soccer players. Separate field and laboratory studies were completed with subjects ingesting a6o/o carbohydrate (CHO), 6% CIJO + BCAA (4 g.h-' of L-leucine), or flavored water placebo (PLA) beverage on three separate occasions. Subjects ingested 6 ml.kg-r of beverage immediately prior to exercise and 3 ml.kg-' every 20 min thereafter for the length of the 120 and 140 min exercise sessions in field and laboratory studies, respectively. Seven collegiate female soccer players (VOzn o* : 52J t 3.7 ml.kg't.min-l) exercised in alternating 10 min bouts on a stationary cycle and treadmill at70Yo andT5Yo voz,,,"*, respectively, for all laboratory sessions. Blood samples from laboratory subjects were drawn and measured for glucose and lactate at rest and at 60, 100, and 140 min of exercise. In both field and laboratory studies, no significant differences in performance, glucose, or lactate values were observed between treatments (p< .05). However, laboratory subjects ingesting the CHO + BCAA beverage performed slightly better than CHO or PLA treatments on tests that may have required a greater degree of central nervous system (CNS) processing. Subjects ingesting the CHO + BCAA beverage hadTYo higher power during the Wingate anaerobic power test compared to CHO and PLA treatments (p:.059), performed zl.syobetter on a shooting test compared to the PLA treatment (p:.058), and reacted about 4Yo faster on a reaction time test than CHO and PLA treatments 0:. 086). It is possible that BCAA ingestion may have attenuated fatigue inducing serotonin (5-hydroxytryptamine; 5-HT) by competing with freetryptophan (f-TRP) for entry into the brain. The results of this study, however, indicate that CHO + BCAA supplementation did not definitively improve skill performance. A larger sample size may have enhanced the statistical power and more clearly delineated the role of BCAA supplementation in sport performance. Further study is needed to determine if a CHO + BCAA supplementation improves skill and cognitive performance by counteracting the fatiguing effects of endurance exercise on the CNS. EFFECT OF A CARBOHYDRATE AND BRANCHED― CHAIN AMINO ACD BEVERAGE ON SKILL PERFORMANCE IN SOCCER PLAYERS A Thesis Presented to the Faculty of the School of Health Sciences and Human Performance at Ithaca College In partial fulfillment of the requirements for the degree Master of Science by Anne Hinko Peddie January 2000 Ithaca College School of Health Sciences and Human Performance Ithaca, New York CERTIFICATE OF APPROVAL MASTER OF SCENCE THESIS This is to certify that the Master of Science Thesis of Anne Hinko Peddie submitted in partial fulfillment of the requirements for the degree of Master of Science in the School of Health Sciences and Human Performance at Ithaca College has been approved. Thesis Advisor: Committee Member: Candidate: Chairperson, Graduate Programs in Exercise And Sport Sciences: Dean of Graduate Studies: Date: a. /, , o ACKNOWLEDGMENTS I would like to take this opportunity to express my appreciation to the following individuals for their assistance in this project: Dr. Gary Sforzo, thesis advisor, for his guidance, invaluable knowledge, kindness, and endless support. Dr. Betsy Keller, co-chair, for her assistance with statistical computations, insightful advice, and input throughout this project. Ithaca College's women's soccer team and coaches, who dedicated much of their time and energy as participants in this project. My fellow grad students, for their efforts as subjects in the pilot study and the countless hours they assisted with data collection. Celeste Choma, fellow grad student, friend, and running partner, for her words of wisdom, support, and open ear, especially during the difficult times. My family and friends, for their words of encouragement, guidance, and love over the years. Thank you all! DEDICATION This thesis is dedicated to three of the most important people in my life. To my parents, Ed and Mary Hinko, for instilling in me a belief that you can achieve anything you want in life through hard work and dedication. To my husband, Mike Peddie, for his friendship, strength, and humor. Thank you for your tremendous love and support. TABLE OF CONTENTS Page ACKNOWLEDGMENTS . 五 DEDICATION . i五 LIST OF FIGURES . 五i RESEARCH MANUSCRIPT INTRODUCTION . 1 METHODS Field Study . ・4 TABLE OF CONTENTS (continued) Page RESEARCH MANUSCRIPT(∞ ndnued) Standing Broad fump . 9 Soccer Skill Tests . 10 Reaction Time and Movement Time Test . 10 Stroop Color and Word Test . 11 Statistical Analysis . 12 RESULTS Blood Glucose and Lactate Wingate Standing Broad Jump Soccer Skill Tests Reaction and Movement Time Stroop Color and Word . ・ DISCUSSION. ・ REFERENCES . ・ 3 3