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Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis

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Background Several studies investigated the effects of caffeine supplementation on movement velocity in resistance exercise. However, these studies presented inconsistent findings. Objective This paper aimed to: (a) review the studies that explored the effects of caffeine supplementation on movement velocity in resistance exercise; and (b) pool their results using a meta-analysis. Methods A search for studies was performed through seven databases. Random-effects meta-analyses of standardized mean differences (SMD) were performed to analyze the data. Sub-group meta-analyses explored the effects of caffeine on different velocity variables (i.e., mean and peak velocity), different loads (i.e., low, moderate, and high loads), and upper- and lower-body exercises. Results Twelve studies met the inclusion criteria. In the main meta-analysis, in which we pooled all available studies, the SMD favored the caffeine condition (SMD = 0.62; 95% confidence interval [CI]: 0.39–0.84; p < 0.001). Sub-group analyses indicated that caffeine significantly enhances mean (SMD = 0.80; 95% CI: 0.48–1.12; p < 0.001) and peak velocity (SMD = 0.41; 95% CI: 0.08–0.75; p = 0.014), movement velocity with low loads (SMD = 0.78; 95% CI: 0.41–1.14; p < 0.001), moderate loads (SMD = 0.58; 95% CI: 0.25–0.91; p = 0.001), and high loads (SMD = 0.70; 95% CI: 0.33–1.07; p < 0.001), as well as in lower-body (SMD = 0.82; 95% CI: 0.42–1.23; p < 0.001) and upper-body exercises (SMD = 0.59; 95% CI: 0.37–0.82; p < 0.001). Conclusion Acute caffeine supplementation is highly ergogenic for movement velocity in resistance exercise. Sub-group analyses indicated that caffeine ingestion is ergogenic: (a) for both mean and peak velocity; (b) for movement velocity when exercising with low, moderate and high loads, and (c) for movement velocity in both lower- and upper-body exercises. Previous meta-analyses that explored the effects of caffeine on various aspects of resistance exercise performance (i.e., muscular strength and endurance) reported trivial to moderate ergogenic effects (effect size range: 0.16–0.38). In the present meta-analysis, the pooled effect size ranged from 0.41 to 0.82. From a resistance exercise performance standpoint, this suggests that caffeine has the most pronounced performance-enhancing effects on movement velocity.
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Vol.:(0123456789)
Sports Medicine (2020) 50:717–729
https://doi.org/10.1007/s40279-019-01211-9
SYSTEMATIC REVIEW
Acute Eects ofCaeine Supplementation onMovement Velocity
inResistance Exercise: ASystematic Review andMeta‑analysis
JavierRaya‑González1· TaraRendo‑Urteaga1· RaúlDomínguez1· DanielCastillo1·
AlejandroRodríguez‑Fernández1· JozoGrgic2
Published online: 23 October 2019
© Springer Nature Switzerland AG 2019
Abstract
Background Several studies investigated the effects of caffeine supplementation on movement velocity in resistance exercise.
However, these studies presented inconsistent findings.
Objective This paper aimed to: (a) review the studies that explored the effects of caffeine supplementation on movement
velocity in resistance exercise; and (b) pool their results using a meta-analysis.
Methods A search for studies was performed through seven databases. Random-effects meta-analyses of standardized mean
differences (SMD) were performed to analyze the data. Sub-group meta-analyses explored the effects of caffeine on differ-
ent velocity variables (i.e., mean andpeak velocity), different loads (i.e., low, moderate, and high loads), and upper- and
lower-body exercises.
Results Twelve studies met the inclusion criteria. In the main meta-analysis, in which we pooled all available studies,
the SMD favored the caffeine condition (SMD = 0.62; 95% confidence interval [CI]: 0.39–0.84; p < 0.001). Sub-group
analyses indicated that caffeine significantly enhances mean (SMD = 0.80; 95% CI: 0.48–1.12; p < 0.001) and peak veloc-
ity (SMD = 0.41; 95% CI: 0.08–0.75; p = 0.014), movement velocity with low loads (SMD = 0.78; 95% CI: 0.41–1.14;
p < 0.001), moderate loads (SMD = 0.58; 95% CI: 0.25–0.91; p = 0.001), and high loads (SMD = 0.70; 95% CI: 0.33–1.07;
p < 0.001), as well as in lower-body (SMD = 0.82; 95% CI: 0.42–1.23; p < 0.001) and upper-body exercises (SMD = 0.59;
95% CI: 0.37–0.82; p < 0.001).
Conclusion Acute caffeine supplementation is highly ergogenic for movement velocity in resistance exercise. Sub-group
analyses indicated that caffeine ingestion is ergogenic: (a) for both mean and peak velocity; (b) for movement velocity when
exercising with low, moderate and high loads, and (c) for movement velocity in both lower- and upper-body exercises. Previ-
ous meta-analyses that explored the effects of caffeine on various aspects of resistance exercise performance (i.e., muscular
strength and endurance) reported trivial to moderate ergogenic effects (effect size range: 0.16–0.38). In the present meta-
analysis, the pooled effect size ranged from 0.41 to 0.82. From a resistance exercise performance standpoint, this suggests
that caffeine has the most pronounced performance-enhancing effects on movement velocity.
1 Introduction
The 2018 International Olympic Committee consensus
statement classified caffeine as a nutritional supplement
that has good evidence of benefits for enhancing exercise
performance [1]. As such, caffeine is widely consumed
by athletes [2]. Studies that examined the prevalence of
caffeine ingestion among different groups of athletes
reported that those competing in strength- and power-
based sports are among the highest users of caffeine—in
terms of the urine concentration of caffeine [2].
Many primary studies and several meta-analy-
ses have explored the effects of caffeine on muscle
strength [310]. The currently published meta-analyses
investigated the effects of caffeine on one-repetition
maximum (1RM), isokinetic, and isometric strength
[35]. These meta-analyses [35] reported ergogenic
effects of caffeine on strength in the effect size mag-
nitude of 0.16 for isokinetic strength (95% confidence
* Jozo Grgic
jozo.grgic@live.vu.edu.au
1 Faculty ofHealth Sciences, Universidad Isabel I, Burgos,
Spain
2 Institute forHealth andSport (IHES), Victoria University,
Melbourne, VIC, Australia
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... In combat sports, caffeine effects are inconsistent [8], which prevents drawing concretized conclusions on this topic. To date, several meta-analyses [19,[24][25][26][27][28][29][30][31][32][33][34][35][36] investigating the impact of caffeine supplementation on sports performance have been conducted. In combat sports specifically, a recent systematic review with a meta-analytic approach [37] was conducted; however, the aforementioned meta-analysis was limited to some combat sports performances and neglected several other variables, such as the handgrip strength, the dynamic strength-endurance performance, the special judo fitness test index, the heart rate, and the rate of perceived exertion. ...
... Heterogeneity was indicated if the Q statistic reached a significance of p < 0.05 and I 2 > 50% [77]. The I 2 statistic was classified as low (<50%), moderate (50-75%) and high (>75%) [34]. Because there was an insufficient number of studies to conduct subgroup or meta-regression analysis, the different moderators that could explain the observed heterogeneity (i.e., dose, timing, form, sample age, sample sex, expertise level, tolerance to caffeine, genetic background, time of day) were discussed in a qualitative way to avoid false positive or negative effect due to a lack of information rather than a smaller (or absent) effect [75]. ...
... This contradiction maybe related to the limited number of studies (i.e., twostudies) included in the aforementioned meta-analysis, thus affecting its validity. Regarding speed and agility, Raya-Gonzalez et al. [34] reported that caffeine has the most pronounced performance-enhancing effects on movement velocity with a pooled effect size ranging from 0.41 to 0.82. Moreover, Salinero et al. [35] found that a moderate dose of caffeine reduced the time to complete agility tests (0.41). ...
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... We used the I 2 statistic to assess the degree of heterogeneity, with values ≤50% indicating low heterogeneity, 50-75% indicating moderate heterogeneity, and >75% indicating high heterogeneity [40]. Potential asymmetries in funnel plots and Egger's linear regression test were employed to detect publication bias [41]. ...
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... In addition, peak velocity in an upper limb resistance exercise seemed to be enhanced with the use of CAF. Velocity in resistance exercise has also been improved after the ingestion of CAF in other studies, such as those reported in the review of Raya-Gonzalez et al. [79]. ...
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Most intervention studies investigating the effects of ergogenic aids (EAs) on sports performance have been carried out in the male population. Thus, the aim of this systematic review and meta-analysis was to summarize the effects in the existing literature of EAs used by female athletes on performance. A literature research was conducted, and a descriptive analysis of the articles included in the systematic review was carried out. Meta-analyses could be performed on 32 of the included articles, evaluating performance in strength, sprint, and cardiovascular capacity. A random-effects model and the standardized mean differences (SMD) ± 95% confidence intervals (CI) were reported. The results showed that caffeine helped to improve jumping performance, isometric strength values, and the number of repetitions until failure. Caffeine and sodium phosphate helped to improve sprint performance. Aerobic tests could be improved with the use of taurine, caffeine, and beta-alanine. No conclusive effects of beetroot juice, polyphenols, or creatine in improving aerobic performance were shown. In terms of anaerobic variables, both caffeine and sodium phosphate could help to improve repeated sprint ability. More studies are needed in female athletes that measure the effects of different EAs on sports performance, such as beetroot juice, beta-alanine or sodium phosphate, as the studies to date are scarce and there are many types of EA that need to be further considered in this population, such as creatine and taurine.
... Caffeine supplementation has been found to increase velocity and power during these exercises. A recent meta-analysis looking at athletes and nonathletes alike showed a load-dependent increase in peak velocity and power during bench press and squat, where increased load showed an increase in peak velocity during lifts after caffeine supplementation (11). When it comes to sport, the studies show that the increase in power and velocity translates to power-generating competition, such as shot put, boxers, cycling, and rowers (4). ...
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Elite athletes often use nutritional supplements to improve performance and gain competitive advantage. The prevalence of nutrient supplementation ranges from 40% to 100% among trained athletes, yet few athletes have a trusted source of information for their supplement decisions and expected results. This critical analysis review evaluates systematic reviews, meta-analyses, randomized control trials, and crossover trials investigating commonly used supplements in sport: caffeine, creatine, beta-alanine (β-alanine), branched chain amino acids (BCAAs), and dietary nitrates. By reviewing these supplements' mechanisms, evidence relating directly to improving sports performance, and ideal dosing strategies, we provide a reference for athletes and medical staff to personalize supplementation strategies. Caffeine and creatine impact power and high-intensity athletes, β-alanine, and BCAA mitigate fatigue, and dietary nitrates improve endurance. With each athlete having different demands, goals to maximize their performance, athletes and medical staff should collaborate to personalize supplementation strategies based on scientific backing to set expectations and potentiate results.
... as manipulating set structures (ie, using cluster or rest redistribution set structures), 11,17 providing velocity feedback, 22,23 and using ergogenic aids such as caffeine. 24 Interestingly, Jukic et al 10 recently showed that even the simple use of lifting straps during deadlifts could provide ergogenic effects on absolute velocity outputs. Although this sounds desirable from a performance-enhancement perspective, the amount of fatigue experienced (eg, velocity decline) was not examined in that study. ...
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Background Using lifting straps during pulling exercises (such as deadlift) may increase absolute velocity performance. However, it remains unclear whether lifting straps could also reduce the degree of relative fatigue measured by velocity decline and maintenance in a training set. Hypothesis There will be less mean velocity decline (MVD) and greater mean velocity maintenance (MVM) for deadlifts performed with (DLw) compared with without (DLn) lifting straps, and an underestimation of MVD and MVM when using the first compared with the fastest repetition as a reference repetition. Study Design Randomized cross over design. Level of Evidence Level 3. Methods A total of 16 resistance-trained men performed a familiarization session, 2 1-repetition maximum [1RM] sessions (1 with and 1 without lifting straps), and 3 randomly applied experimental sessions consisting of 4 sets of 4 repetitions: (1) DLw against the 80% of DLn 1RM (DLwn), (2) DLn against the 80% of the DLn 1RM (DLnn), and (3) DLw against the 80% of the DLw 1RM (DLww). MVD and MVM were calculated using the first and the fastest repetition as the reference repetition. Results MVD was significantly lower during DLwn and DLnn compared with DLww ( P < 0.01), whereas MVM was greater during DLwn and DLnn compared with DLwn ( P < 0.01) with no differences between DLwn and DLnn for both MVD and MVM ( P > 0.05). The second repetition of the set was generally the fastest (54.1%) and lower MVD and higher MVM were observed when the first repetition was used as the reference repetition ( P < 0.05). Conclusions Lifting straps were not effective at reducing MVD and increasing MVM when the same absolute loads were lifted. Furthermore, using the first repetition as the reference repetition underestimated MVD, and overestimated MVM. Clinical relevance The fastest repetition should be used as the reference repetition to avoid inducing excessive fatigue when the first repetition is not the fastest.
... This might suggest that CAF has a more pronounced effect on muscle contraction velocity rather than on maximal force production during the BP exercise. Moreover, recently performed meta-analysis confirmed that CAF is highly ergogenic as regards to movement velocity during resistance exercise [45], which is also observed for the BP exercise (Table 2). It should be noted, that the effects of CAF might not be uniform [41]. ...
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Background Caffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power. Methods A search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump. Meta-analyses of standardized mean differences (SMD) between placebo and caffeine trials from individual studies were conducted using the random effects model. Results Ten studies on the strength outcome and ten studies on the power outcome met the inclusion criteria for the meta-analyses. Caffeine ingestion improved both strength (SMD = 0.20; 95% confidence interval [CI]: 0.03, 0.36; p = 0.023) and power (SMD = 0.17; 95% CI: 0.00, 0.34; p = 0.047). A subgroup analysis indicated that caffeine significantly improves upper (SMD = 0.21; 95% CI: 0.02, 0.39; p = 0.026) but not lower body strength (SMD = 0.15; 95% CI: -0.05, 0.34; p = 0.147). Conclusion The meta-analyses showed significant ergogenic effects of caffeine ingestion on maximal muscle strength of upper body and muscle power. Future studies should more rigorously control the effectiveness of blinding. Due to the paucity of evidence, additional findings are needed in the female population and using different forms of caffeine, such as gum and gel.
Purpose: To explore the effects of three doses of caffeine on muscle strength and muscle endurance. Methods: Twenty-eight resistance-trained men completed the testing sessions under five conditions: no-placebo control, placebo-control, and with caffeine doses of 2, 4, and 6 mg.kg−1. Muscle strength was assessed using the one-repetition maximum (1RM) test; muscle endurance was assessed by having the participants perform a maximal number of repetitions with 60% 1RM. Results: In comparisons with both control conditions, only a caffeine dose of 2 mg.kg−1 enhanced lower-body strength (d=0.13–0.15). In comparisons with the no-placebo control condition, caffeine doses of 4 mg.kg−1 and 6 mg.kg−1 enhanced upper-body strength (d=0.07–0.09) with a significant linear trend for the effectiveness of different doses of caffeine (p=0.020). Compared to both control conditions, all three caffeine doses enhanced lower-body muscle endurance (d=0.46–0.68). For upper-body muscle endurance, we did not find significant effects of caffeine. Conclusions: We found a linear trend between the dose of caffeine and its effects on upper-body strength. This study found no clear association between the dose of caffeine and the magnitude of its ergogenic effects on lower-body strength and muscle endurance. From a practical standpoint, the magnitude of caffeine’s effects on strength is of questionable relevance. A low dose of caffeine (2 mg.kg−1)—for an 80kg individual, this dose of caffeine contained in one to two cups of coffee—may produce substantial improvements in lower-body muscle endurance with the magnitude of the effect being similar to that attained using higher doses of caffeine.
Purpose: To examine the acute effects of three doses of caffeine on upper- and lower-body ballistic exercise performance, and to explore if habitual caffeine intake impacts the acute effects of caffeine ingestion on ballistic exercise performance. Methods: Twenty recreationally active male participants completed medicine ball throw and vertical jump tests under four experimental conditions (placebo, 2, 4, and 6 mg·kg-1 of caffeine). Results: One-way repeated measures ANOVA with subsequent post hoc analyses indicated that performance in the medicine ball throw test improved, compared to placebo, only with a 6 mg·kg-1 dose of caffeine (P=0.032). Effect size, calculated as the mean difference between the two measurements divided by the pooled standard deviation, amounted to 0.29 (+3.7%). For the vertical jump test, all three caffeine doses were effective (compared to placebo) for acute increases in performance (P values ranged from 0.022 to 0.044; effect sizes from 0.35 to 0.42; percent changes from +3.7% to +4.1%). A two-way repeated measures ANOVA indicated that there was no significant group x condition interaction effect, suggesting comparable responses between low (<100 mg·day-1) and moderate-to-high (>100 mg·day-1) caffeine users to the experimental conditions. Conclusion: Caffeine doses of 2, 4, and 6 mg·kg-1 seem to be effective for acute enhancements in lower-body ballistic exercise performance in recreationally trained male individuals. For the upper-body ballistic exercise performance, only a caffeine dose of 6 mg·kg-1 seems to be effective. The acute effects of caffeine ingestion do not seem to be impacted by habitual caffeine intake; however, this requires further exploration.
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Objectives The aims of this paper are threefold: (1) to summarize the research examining the effects of caffeine on isokinetic strength, (2) pool the effects using a meta-analysis, and (3) to explore if there is a muscle group or a velocity specific response to caffeine ingestion. Design Meta-analysis. Methods PubMed/MEDLINE, Scopus, and SPORTDiscus were searched using relevant terms. The PEDro checklist was used for the assessment of study quality. A random-effects meta-analysis of standardized mean differences (SMDs) was done. Results Ten studies of good and excellent methodological quality were included. The SMD for the effects of caffeine on strength was 0.16 (95% CI = 0.06, 0.26; p = 0.003; +5.3%). The subgroup analysis for knee extensor isokinetic strength showed a significant difference (p = 0.004) between the caffeine and placebo conditions with SMD value of 0.19 (95% CI = 0.06, 0.32; +6.1%). The subgroup analysis for the effects of caffeine on isokinetic strength of other, smaller muscle groups indicated no significant difference (p = 0.092) between the caffeine and placebo conditions. The subgroup analysis for knee extensor isokinetic strength at angular velocities of 60°·s−1 and 180°·s−1 showed a significant difference between the caffeine and placebo conditions with SMD value of 0.21 (95% CI = 0.07, 0.36; p = 0.004; +6.0%) and 0.23 (95% CI = 0.07, 0.38; p = 0.005; +5.5%), respectively. No significant effect (p = 0.193) was found at an angular velocity of 30°·s−1. Conclusions This meta-analysis demonstrates that acute caffeine ingestion caffeine may significantly increase isokinetic strength. Additionally, this meta-analysis reports that the effects of caffeine on isokinetic muscular strength are predominantly manifested in knee extensor muscles and at greater angular velocities.