title: Supercompensated glycogen loads persist 5 days in resting trained cyclists.
abstract: Research data indicates a persistence of elevated muscle glycogen concentration 3 days post-supercompensation in resting athletes. This study expands our earlier findings by determining whether muscle glycogen remains elevated 3, 5, or 7 days post-supercompensation. Seventeen trained male cyclists underwent one bout of exhaustive exercise to deplete muscle glycogen. This was followed by a 3-day consumption of a high carbohydrate/low protein/low fat diet (85:08:07%). Three post-loading phases followed with subjects randomly assigned to either a 3-day, 5-day, or 7-day post-loading maintenance diet of 60% carbohydrate and limited physical activity. Biopsies (50-150 mg) of the vastus lateralis were obtained pre-load (BASELINE), at peak-load (PEAK), and either at 3-day, 5-day, or 7-day post-load (POST). On average, PEAK to POST muscle glycogen concentrations decreased 34, 20 and 46% respectively for the 3-, 5-, and 7-day POST groups. Only the 7-day post-load group's PEAK to POST mean muscle glycogen concentration decreased significantly. In addition, multi-regression analysis indicated that the PEAK glycogen level was the main determinant of the number of days that glycogen levels remained significantly greater than BASELINE. Thus, trained athletes' supercompensated glycogen levels can remain higher than normal for up to 5 days post-loading. The amount of carbohydrate consumed, the level of physical activity, and the magnitude of the glycogen supercompensation determine the interval for which the glycogen levels are elevated.
authors.affiliation: East Tennessee State University, Physical Therapy Program, PO Box 70624, Johnson City, TN 37614, USA. arnall@etsu.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Arnall
authors.forename: Arnold G
authors.initials: AG
authors.lastname: Nelson
authors.forename: Jack
authors.initials: J
authors.lastname: Quigley
authors.forename: Stephen
authors.initials: S
authors.lastname: Lex
authors.forename: Tom
authors.initials: T
authors.lastname: Dehart
authors.forename: Peggy
authors.initials: P
authors.lastname: Fortune
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling; D018752:Diet, Fat-Restricted; D018753:Diet, Protein-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004435:Eating; D006003:Glycogen / Q000378:metabolism*; D006339:Heart Rate; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D012044:Regression Analysis; D012146:Rest / Q000502:physiology*; D013997:Time Factors
chemical_list: D004040:Dietary Carbohydrates; D006003:Glycogen