title: Effects of sodium phosphate and caffeine ingestion on repeated-sprint ability in male athletes.
abstract: OBJECTIVE
  To assess the effects of sodium phosphate (SP) and caffeine supplementation on repeated-sprint performance.
  
  
  METHODS
  Randomized, double-blind, Latin-square design.
  
  
  METHODS
  Eleven team-sport males participated in four trials: (1) SP (50mgkg(-1) of free fat-mass daily for six days) and caffeine (6mgkg(-1) ingested 1h before exercise); SP+C, (2) SP and placebo (for caffeine), (3) caffeine and placebo (for SP) and (4) placebo (for SP and caffeine). After loading, participants performed a simulated team-game circuit (STGC) consisting of 2×30min halves, with 6×20-m repeated-sprint sets performed at the start, half-time and end of the STGC.
  
  
  RESULTS
  There were no interaction effects between trials for first-sprint (FS), best-sprint (BS) or total-sprint (TS) times (p>0.05). However, SP resulted in the fastest times for all sprints, as supported by moderate to large effect sizes (ES; d=0.51-0.83) and 'likely' to 'very likely' chances of benefit, compared with placebo. Compared with caffeine, SP resulted in 'possible' to 'likely' chances of benefit for FS, BS and TS for numerous sets and a 'possible' chance of benefit compared with SP+C for BS (set 2). Compared with placebo, SP+C resulted in moderate ES (d=0.50-0.62) and 'possible' to 'likely' benefit for numerous sprints, while caffeine resulted in a moderate ES (d=0.63; FS: set 3) and 'likely' chances of benefit for a number of sets.
  
  
  CONCLUSIONS
  While not significant, ES and qualitative analysis results suggest that SP supplementation may improve repeated-sprint performance when compared with placebo.
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Australia.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Kopec
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Australia.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Dawson
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Buck
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, Australia. Electronic address: karen.wallman@uwa.edu.au.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Wallman
mesh_terms: D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D002110:Caffeine / Q000008:administration & dosage* / Q000097:blood; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D010710:Phosphates / Q000008:administration & dosage* / Q000097:blood; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D010710:Phosphates; D002110:Caffeine; C018279:sodium phosphate
keywords: Aerobic exercise; Dietary supplements; Sports performance; Team-sports