Acute caffeine supplementation improves jumping, sprinting, and change‐of‐direction performance in basketball players when ingested in the morning but not evening

Abstract

This study compared the effects of acute caffeine supplementation (3 mg/kg) administered in the morning and evening on performance-related variables in basketball players. Eleven, national-level, adolescent male basketball players underwent field-based fitness testing on four occasions: morning (10:00) with caffeine ingestion (AM_CAFF), morning (10:00) with placebo ingestion (AM_PLAC), evening (21:00) with caffeine ingestion (PM_CAFF), and evening (21:00) with placebo ingestion (PM_PLAC). Fitness testing included of a countermovement jump without arm swing (CMJ), CMJ with arm swing (CMJAS), squat jump (SJ), Lane Agility Drill (LAD), 20-m linear sprint, and Suicide Run with (SRD) and without dribbling (SR). Data were analysed using two-way repeated measures analyses of variance and paired t-tests, with effect sizes (ES) also determined for all pairwise comparisons. Follow-up t-test comparisons revealed that AM_CAFF produced <i>small-moderate</i>, significant (<i>p</i><0.001), improvements in CMJ (ES = 0.51), CMJAS (ES = 0.40), SJ (ES = 0.51), and SR (ES = -0.45) compared to AM_PLAC. AM_CAFF also produced a <i>moderate</i>, significantly (<i>p</i><0.001) faster LAD (ES = -0.61) compared to PM_CAFF. PM_PLAC demonstrated <i>small-moderate</i>, significant (<i>p</i><0.05) improvements in CMJ (ES = 0.43), CMJAS (ES = 0.48), and 20-m sprint (ES = -0.63) compared to AM_PLAC. In contrast, AM_PLAC resulted in <i>large,</i> significantly (<i>p</i><0.001), faster SRD (ES = -1.46) and SR (ES = -1.59) compared to PM_PLAC. Given the ergogenic effects of caffeine during basketball-specific fitness tests appear to be influenced by time of ingestion, basketball practitioners should consider administering caffeine only to players in the morning to improve vertical jump, sprinting, and change-of-direction performance, with no beneficial effects observed with caffeine ingestion in the evening.<b>Highlights</b> The effect of caffeine supplementation on basketball-specific performance related variables were mediated by ingestion time in elite, adolescent basketball players.AMCAFF produced small-moderate improvements in vertical jump, change-of-direction, 20-m linear sprint, and repeated-sprint performance compared to AMPLAC while PMCAFF produced trivial differences in each performance-related variable compared to PMPLAC.Comparisons between ingestion times in the placebo condition revealed vertical jump height and 20-m sprint speed were impaired in the morning compared to the evening, but these time-dependent differences were eliminated when caffeine was consumed in the morning.Basketball practitioners should consider administering caffeine only to players in the morning to improve vertical jump, sprinting, and change-of-direction performance, with no beneficial effects observed with caffeine ingestion in the evening.