This investigation determined whether carbohydrate ingestion during prolonged moderate-intensity exercise enhanced endurance performance when the exercise was preceded by carbohydrate supercompensation. Seven male trained cyclists performed two trials at an initial power output corresponding to 71 ± 1 % of their peak oxygen consumption. During the trials, subjects ingested either a 6% glucose/sucrose (C) solution or an equal volume of artificially flavored and sweetened placebo (P) every 20 min throughout exercise. Both C and P were preceded by a 6-day carbohydrate supercompensation procedure in which subjects undertook a depletion-taper exercise sequence in conjunction with a moderate- and high-carbohydrate diet regimen. Statistical analysis of time to exhaustion, plasma glucose concentration, carbohydrate oxidation rate, fat oxidation rate, and plasma glycerol concentration indicated that in spite of a carbohydrate supercompensation procedure administered prior to exercise, carbohydrate ingestion during exercise can exert an additional ergogenic effect by preventing a decline in blood glucose levels and maintaining carbohydrate oxidation during the later stages of moderate-intensity exercise.
J. Kang is with the Department of Health and Exercise Sciences, Rowan College of New Jersey, Glassboro, NJ 08028. R.J. Robertson, S.G. DaSilva, R.R. Suminski, A.C. Utter, F.L. Goss, and K.F. Metz are with the Department of Health and Physical Education, University of Pittsburgh, Pittsburgh, PA 15261. B.G. Denys is with the Department of Cardiology, Presbyterian University Hospital, Pittsburgh, PA 15213. P. Visich is with the Department of Health Promotion and Rehabilitation, Central Michigan University, Mt. Pleasant, MI 48859.