Benjamin J Kopec1, Brian T Dawson1, Christopher Buck1, Karen E Wallman2. 1. School of Sport Science, Exercise and Health, The University of Western Australia, Australia. 2. School of Sport Science, Exercise and Health, The University of Western Australia, Australia. Electronic address: karen.wallman@uwa.edu.au.
Abstract
OBJECTIVES: To assess the effects of sodium phosphate (SP) and caffeine supplementation on repeated-sprint performance. DESIGN: 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.
RCT Entities:
OBJECTIVES: To assess the effects of sodium phosphate (SP) and caffeine supplementation on repeated-sprint performance. DESIGN: 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: Chad M Kerksick; Colin D Wilborn; Michael D Roberts; Abbie Smith-Ryan; Susan M Kleiner; Ralf Jäger; Rick Collins; Mathew Cooke; Jaci N Davis; Elfego Galvan; Mike Greenwood; Lonnie M Lowery; Robert Wildman; Jose Antonio; Richard B Kreider Journal: J Int Soc Sports Nutr Date: 2018-08-01 Impact factor: 5.150
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