Purpose: To investigate the effect of ingesting a carbohydrate-electrolyte solution (CHO-E), in subjects with reduced carbohydrate stores, during an intermittent shuttle running test (LIST) on soccer passing (LSPT) and shooting (LSST) performance.
Methods: Sixteen healthy male university soccer players ingested either a 6.4% CHO-E or placebo (PLA) solution during 90 min of the LIST (5 mL·kg−1 BM before and 2 mL·kg−1 BM every 15 min of exercise), in a double-blind, randomized, crossover design, with each trial separated by at least 7 d. On the evening before the main trial (17:00 h), subjects performed the glycogen-reducing cycling exercise (~80 min at 70% V˙O2max). They were then fed a low-carbohydrate evening meal and reported to the laboratory the following morning after a 10-h fast. Blood was collected at rest and after every 30 min of exercise; skill tests were performed before and after the LIST.
Results: The change in mean LSST performance from pre- to post-LIST was better in the CHO-E trial (11 ± 45 vs −16 ± 42%; P < 0.01) but not significantly different for the LSPT performance (−1 ± 10% (CHO-E) vs −6 ± 13% (PLA), P = 0.13). Sprint performance during the LIST was quicker in the CHO-E trial (2.50 ± 0.13 vs 2.53 ± 0.13 s, P < 0.01). Plasma glucose was higher in the CHO-E trial after 90 min of exercise (5.2 ± 0.3 vs 3.9 ± 0.4 mM, P < 0.01).
Conclusions: Ingestion of a carbohydrate-electrolyte solution during exercise enabled subjects with compromised glycogen stores to better maintain skill and sprint performance than when ingesting fluid alone.
1Institute of Food, Nutrition and Human Health, Massey University, Auckland, NEW ZEALAND; 2School of Sport and Exercise Sciences, Loughborough University, Loughborough, Leicestershire, UNITED KINGDOM; and 3University of Chester, Parkgate Road, Chester, UNITED KINGDOM
Address for correspondence: Ajmol Ali, Ph.D., Institute of Food, Nutrition and Human Health, Massey University, Albany, Auckland, New Zealand; E-mail: firstname.lastname@example.org.
Submitted for publication April 2006.
Accepted for publication July 2007.