title: Sodium phosphate loading improves laboratory cycling time-trial performance in trained cyclists.
abstract: Sodium phosphate loading has been reported to increase maximal oxygen uptake (6-12%), however its influence on endurance performance has been ambiguous. The aim of this study was to examine the influence of sodium phosphate loading on laboratory 16.1 km cycling time-trial performance. Six trained male cyclists (V O(2) peak, 64.1+/-2.8 ml kg(-1)min(-1); mean+/-S.D.) took part in a randomised double-blind crossover study. Upon completion of a control trial (C), participants ingested either 1g of tribasic dodecahydrate sodium phosphate (SP) or lactose placebo (P) four times daily for 6 days prior to performing a 16.1 km (10 mile) cycling time-trial under laboratory conditions. Power output and heart rate were continually recorded throughout each test, and at two points during each time-trial expired air samples and capillary blood samples were taken. There was a 14-day period between each of the supplemented time-trials. After SP loading mean power was greater than for P and C (C, 322+/-15 W; P, 317+/-16 W; SP, 347+/-19 W; ANOVA, P<0.05) and time to complete the 16.1 km was shorter than P, but not C (ANOVA, P<0.05). During the SP trial, relative to the P, mean changes were mean power output +9.8+/-8.0% (+/-95% confidence interval); time -3.0+/-2.9%. There was a tendency towards higher V O(2) after SP loading (ANOVA, P = 0.07). Heart rate, V (E), RER and blood lactate concentration were not significantly affected by SP loading. Sodium phosphate loading significantly improved mean power output and 16.1 km time-trial performance of trained cyclists under laboratory conditions with functional increases in oxygen uptake.
authors.affiliation: School of Sport and Exercise Sciences, Loughborough University, UK. j.p.folland@lboro.ac.uk
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Folland
authors.forename: Ric
authors.initials: R
authors.lastname: Stern
authors.forename: Gary
authors.initials: G
authors.lastname: Brickley
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D002400:Cathartics / Q000008:administration & dosage* / Q000494:pharmacology; D018592:Cross-Over Studies; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010710:Phosphates / Q000008:administration & dosage* / Q000494:pharmacology; D010807:Physical Endurance; D013997:Time Factors; D055815:Young Adult
chemical_list: D002400:Cathartics; D010710:Phosphates; C018279:sodium phosphate