title: Exercise performance as a function of semi-solid and liquid carbohydrate feedings during prolonged exercise.
abstract: Aim of this study was to examine the effects of a semi-solid and a liquid carbohydrate feeding on exercise performance. Thirty-two male triathletes performed three exercise trials (3 hours maximal at 75% VO2max) with either a semi-solid feeding (S), an iso-caloric liquid feeding (F) or a liquid placebo (P). Exercise consisted of cycling (bout 1 and 3) and running (bout 2 and 4). Survival analysis revealed that the median maximum test time (MTT) with F, S and P was 180, 126 and 120 min, respectively. Median MTT was longer with F than with S (sign-test; p < 0.05) or P (p < 0.001), with no difference between S and P. Mean power output during supra-maximal tests after bout 2 (W1) and at the end of exercise (Wend) were 371, 365, 362 and 334, 332, 321 W with F, S and P, respectively. Differences between F and P were significant (p < 0.01). Regression analysis identified five variables that were associated with 93% of the variance in MTT. The variance in W1 was explained for 83% by three variables. Wend was explained (90%) by three variables. A significant dietary contribution to MTT and Wend was found, but not to W1. This suggests that the influence of the feedings on performance is different among performance tests.
authors.affiliation: Department of Medical Physiology and Sports Medicine, University of Utrecht, The Netherlands.
authors.forename: H P
authors.initials: HP
authors.lastname: Peters
authors.forename: W F
authors.initials: WF
authors.lastname: van Schelven
authors.forename: P A
authors.initials: PA
authors.lastname: Verstappen
authors.forename: R W
authors.initials: RW
authors.lastname: de Boer
authors.forename: E
authors.initials: E
authors.lastname: Bol
authors.forename: W B
authors.initials: WB
authors.lastname: Erich
authors.forename: C R
authors.initials: CR
authors.lastname: van der Togt
authors.forename: W R
authors.initials: WR
authors.lastname: de Vries
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004311:Double-Blind Method; D002149:Energy Intake; D004734:Energy Metabolism; D005080:Exercise Test; D005526:Food, Formulated; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D010919:Placebos; D011597:Psychomotor Performance / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology*; D016019:Survival Analysis; D013550:Swimming / Q000502:physiology*
chemical_list: D004040:Dietary Carbohydrates; D010919:Placebos