A Randomised, Placebo-Controlled, Crossover Study Investigating the Optimal Timing of a Caffeine-Containing Supplement for Exercise Performance.
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ABSTRACT: BACKGROUND:Pre-exercise supplements containing low doses of caffeine improve endurance exercise performance, but the most efficacious time for consumption before intense endurance exercise remains unclear, as does the contribution of caffeine metabolism. METHODS:This study assessed the timing of a commercially available supplement containing 200?mg of caffeine, 1600?mg of ?-alanine and 1000?mg of quercetin [Beachbody Performance Energize, Beachbody LLC, USA] on exercise performance, perception of effort and plasma caffeine metabolites. Thirteen cyclists (V?O2max 64.5?±?1.4 ml?kg-?1?min-?1 (±?SEM)) completed four experimental visits consisting of 30?min of steady-state exercise on a cycle ergometer at 83?±?1% V?O2max followed by a 15-min time trial, with perceived exertion measured regularly. On three of the visits, participants consumed caffeine either 35?min before steady-state exercise (PRE), at the onset of steady-state (ONS) or immediately before the time trial (DUR) phases, with a placebo consumed at the other two time points (i.e. three drinks per visit). The other visit (PLA) consisted of consuming the placebo supplement at all three time points. The placebo was taste-, colour- and calorie-matched. RESULTS:Total work performed during the time trial in PRE was 5% greater than PLA (3.53?±?0.14 vs. 3.36?±?0.13?kJ?kg-?1 body mass; P?=?0.0025), but not ONS (3.44?±?0.13?kJ?kg-?1; P?=?0.3619) or DUR (3.39?±?0.13?kJ?kg-?1; P?=?0.925), which were similar to PLA. Perceived exertion was lowest during steady-state exercise in the PRE condition (P?
SUBMITTER: Davenport AD
PROVIDER: S-EPMC7105519 | biostudies-literature | 2020 Mar
REPOSITORIES: biostudies-literature
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