Caffeine ingestion attenuates diurnal variation of lower‐body ballistic performance in resistance‐trained women

Abstract

The present study investigates the effect of an acute intake of caffeine on the diurnal variation of neuromuscular performance in resistance-trained women. A total of 15 resistance-trained women participated in the current triple-blind, placebo-controlled, crossover experimental study. We assessed neuromuscular performance (i.e. ballistic (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximal strength (squat and bench press [BP] onerepetition maximum [1RM]), and strength-endurance [average velocity of the set during squat and number of repetitions-to-failure in BP]) four times at within 7 days. The participants ingested an acute dose of caffeine (3 mg/kg) or a placebo at 9-11 am and/or 17-19 pm. CMJ height (P = .016) and BP peak velocity (P = .012) were higher in the afternoon than in the morning. Compared to placebo, caffeine intake increased CMJ height by 3.1% in the morning and 1.6% in the afternoon (P = .035), but it had no effect on BPT peak velocity (P = .381). Maximal strength and strength-endurance performances were not affected by the time-of-day or caffeine intake (all P > .3). No significant interaction (time-of-day x substance) was observed in any of the above-mentioned outcomes (all P > .1). In conclusion, an acute dose of caffeine in the morning was effective to restore CMJ performance to levels found in the afternoon, while this effect was not observed neither in BPTpeak velocity nor in lower-and upper-body maximal strength and strength-endurance performance. Moreover, lower-and upper-body ballistic performance were greater in the afternoon than in the morning in resistance-trained women, while the acute intake of caffeine was only effective to increase CMJ height. Highlights. Ballistic performance is probably higher in the afternoon than in the morning in resistancetrained women. . An acute intake of caffeine is effective to increase countermovement jump performance.. The ingestion of an acute dose of caffeine in the morning restored countermovement jump performance to levels found in the afternoon.

Ergogenic Effects of Caffeine on Ballistic (Throwing) Performance: A Meta-Analytical Review

“…Nine studies were excluded, most commonly because they did not provide isolated caffeine supplementation or did not evaluate ballistic throwing performance [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. As a result, nine articles [ 11 , 12 , 13 , 14 , 15 , 17 , 18 , 19 , 20 ] were found to satisfy the inclusion criteria in the primary search. There were 694 search results in the secondary search, even though no additional studies were found to satisfy the inclusion criteria.…”

“…One study [ 16 ] from the lead author’s personal collection of articles was found to satisfy the inclusion criteria. Therefore, ten studies were included in the review [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] ( Figure 1 ). While there were ten included studies, there were 11 groups included in the meta-analysis due to the fact that one study [ 17 ] had two groups of participants who possessed different genotype variations.…”

“…The average value of r = 0.89 was used for all studies in the analysis. Several studies provided multiple related performance outcomes (e.g., throwing performance following the ingestion of two different caffeine doses) [ 11 , 13 , 14 , 17 , 18 , 19 , 20 ]. As these were outcomes collected in the same group of participants, SMDs and variances were first calculated separately for each outcome.…”

“…Findings in subsequent studies varied, as some have also reported an ergogenic effect [ 14 , 15 , 16 ], while one study suggested that performance-enhancing benefits are attained only with higher caffeine doses [ 19 ]. At the same time, several studies [ 12 , 18 ] reported no significant difference between caffeine and placebo. Due to the conflicting data, specific recommendations regarding caffeine supplementation for throwing performance cannot be established.…”

“…Caffeine is a highly popular ergogenic aid, with established performance-enhancing effects in various exercise modes [ 8 , 9 , 10 ]. However, an examination of the findings reported in primary studies highlights that caffeine’s effects on throwing performance are inconsistent [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Specifically, the first study [ 11 ] on this topic observed that caffeine consumption improved throwing performance in the shot put; however, an ergogenic effect was found only in one out of the six performed throwing attempts.…”