Search Results (324)

Coffee is widely consumed by physically active individuals and athletes, often with the intention of enhancing alertness, reducing fatigue and supporting exercise performance. Its performance-related effects are primarily attributed to caffeine; however, responses to coffee consumption vary substantially across individuals and type of training. This narrative review examines current evidence on the role of coffee consumption in sport, with particular emphasis on caffeine-related mechanisms, physical performance, fatigue, muscle pain and recovery, as well as factors modifying individual responses, including circadian rhythm, habitual intake and genetic variability. Available evidence indicates that coffee consumption prior to physical activity may support endurance performance, reduce perceived exertion and attenuate muscle pain, particularly during prolonged or demanding exercise and under conditions of sleep restriction or circadian misalignment. In contrast, effects on muscle strength and power performance appear less consistent and more context dependent. Interindividual differences in caffeine metabolism, sensitivity to stimulation and susceptibility to sleep disruption further influence both the effectiveness and tolerability of coffee intake. Emerging findings also suggest that coffee, when consumed in combination with carbohydrates, may enhance post-exercise muscle glycogen resynthesis, a potential benefit of particular relevance for endurance athletes facing limited recovery time. At the same time, evidence regarding non-caffeine bioactive compounds present in coffee remains limited and largely indirect, indicating a modulatory rather than ergogenic role. Overall, coffee should not be regarded as a universally effective ergogenic aid, as its effects may vary according to individual characteristics, training demands and the timing of consumption. Its effective use requires careful consideration of individual characteristics, training demands and timing of consumption, underscoring the importance of personalized strategies in both performance and recovery settings. Full article

Creatine monohydrate is well supported as an ergogenic aid in adults, but age-specific evidence in adolescent athletes remains limited. This critical narrative review examined performance, safety, dosing, and responsible-use considerations. PubMed/MEDLINE was the primary source; citation tracking, the Cochrane Library, ClinicalTrials.gov, Google Scholar, and Semantic Scholar were used through 19 June 2026. The core athletic synthesis included 17 primary studies: five Tier 1 studies with direct adolescent samples, eleven Tier 2 age-adjacent or mixed-age studies, and one Tier 4 adult study retained for contextual interpretation. Across soccer, swimming, basketball, rehabilitation, and resistance-training settings, controlled studies reported possible task-specific improvements in selected power, repeated-sprint, jumping, technical, and rehabilitation outcomes, whereas other outcomes were unchanged and some favorable findings were limited to within-group analyses. Short-term controlled studies and a 32-week mixed-age cohort did not identify a consistent clinically important safety signal within the protocols studied; however, safety monitoring was often secondary and the evidence remains underpowered for uncommon or long-term events. Creatine monohydrate should therefore be neither routinely recommended nor categorically prohibited in adolescent athletes. Any consideration represents a precautionary, individualized risk-management approach—not a validated adolescent protocol—and should be food-first, family-involved, professionally supervised, and accompanied by product-quality control and planned reassessment. Full article

Background/Objectives: Ammonia inhalants, commonly known as smelling salts, are widely used in sport as an acute arousal strategy, yet their ergogenic value remains uncertain. This systematic review and three-level meta-analysis examined the acute effects of ammonia inhalation on physical performance and selected psychophysiological outcomes. Methods: Controlled human studies involving healthy adults, physically active individuals, or athletes were included when they compared ammonia inhalation with placebo, sham, or no-inhalation control conditions. Physical performance was the primary outcome, with heart rate and selected subjective responses analyzed as exploratory secondary outcomes. Results: Ten studies were included. The primary analysis showed no statistically significant effect of ammonia inhalation on overall physical performance (k = 47, g = 0.11, 95% CI [−0.06, 0.28]). Heart rate and subjective exertion/fatigue were also not significantly affected. In contrast, subjective activation/arousal increased significantly (k = 9, g = 0.73, 95% CI [0.43, 1.04]), although this finding was based on only two studies. Moderator analyses did not show consistent subgroup differences for performance type, training status, or comparator type, whereas sex-based differences were exploratory and based on limited evidence. Sensitivity analyses suggested that physical performance became significantly improved after removal of influential effects, and power/explosive performance showed a possible benefit; however, these findings should be considered preliminary rather than confirmatory. Conclusions: Overall, ammonia inhalation appears to act primarily as a brief arousal stimulus rather than a consistent ergogenic aid. Potential benefits may depend on task demands, with explosive or repeated high-intensity tasks appearing more plausible targets than maximal strength or precision-based skills. Current evidence remains limited by small samples, heterogeneous protocols, and low certainty. Full article

Background/Objectives: Cognitive fatigue and impaired psychomotor function may contribute to reductions in football-specific performance during prolonged match-like activity. This study evaluated cognitive, psychomotor, sprint, and football-specific locomotor responses to multi-ingredient protocols containing taurine, caffeine, and either 300 or 600 mg·day⁻¹ of phosphatidylserine in professional male football players. Methods: In this randomized, triple-masked, placebo-controlled, parallel-group trial, 97 professional male football players were allocated to placebo (PLA, n = 24), taurine plus caffeine (TC, n = 24), taurine plus caffeine plus phosphatidylserine 300 mg·day⁻¹ (TCP-300, n = 24), or taurine plus caffeine plus phosphatidylserine 600 mg·day⁻¹ (TCP-600, n = 25) for 14 days. Taurine and caffeine doses were 1500 mg·day⁻¹ and 200 mg·day⁻¹, respectively. Outcomes included 30 m sprint performance, visual and auditory reaction time, Stroop-task performance, perceived mental fatigue, GPS-derived locomotor variables, and post-intervention first-to-second-half performance-loss indices during a standardized football-specific exercise protocol. Results: The baseline-adjusted ANCOVA demonstrated a significant treatment-group effect on post-intervention 30 m sprint time. After Holm–Bonferroni correction, significant treatment-related effects remained for Stroop reaction time, visual reaction time, and perceived mental fatigue. No statistically significant treatment-related effect was observed for auditory reaction time (unadjusted p = 0.074; Holm-adjusted p = 0.096). During the post-intervention standardized football-specific protocol, baseline-adjusted GPS-derived locomotor outcomes differed significantly between groups. First-to-second-half performance-loss indices also differed between groups, with the smallest post-intervention losses generally observed in TCP-600. Because comparable decline indices were unavailable at baseline, these findings do not represent intervention-related changes in fatigue resistance. Conclusions: Under the present 14-day experimental conditions, the multi-ingredient protocols containing taurine, caffeine, and phosphatidylserine were associated with more favorable selected cognitive and psychomotor outcomes, 30 m sprint performance, and baseline-adjusted GPS-derived locomotor outcomes than placebo. The groups also differed in post-intervention first-to-second-half performance loss during the standardized football-specific protocol. Because corresponding decline indices were not assessed at baseline, these findings do not demonstrate an intervention-related improvement in fatigue resistance. Numerically more favorable values were observed for several outcomes in TCP-600; however, differences between TCP-300 and TCP-600 were modest and not consistently statistically significant, and the study was not specifically powered to establish a dose–response relationship. Because phosphatidylserine was not tested independently, these findings should be interpreted as responses to the combined multi-ingredient supplementation protocols rather than as effects of phosphatidylserine alone. Full article

Background: Beetroot-derived nitrate supplementation is a widely studied nutritional strategy to enhance athletic performance. Although ergogenic benefits have been reported in recreational and moderately trained individuals, evidence for highly trained and elite athletes remains inconsistent. Objectives: This scoping review aimed to map and synthesize evidence from randomized controlled trials (RCTs) investigating the effects of beetroot-derived nitrate supplementation on performance, recovery, and physiological outcomes in highly trained and elite athletes. Methods: The review followed the Joanna Briggs Institute methodology and PRISMA-ScR guidelines. Literature searches were conducted in PubMed, Scopus, and Web of Science. Eligible studies included RCTs involving McKay Tier 3–5 athletes and evaluating beetroot-derived nitrate supplementation as a standalone intervention. Results: Thirty-one RCTs met the inclusion criteria, representing athletes from a wide range of sports. Supplementation protocols varied substantially, with nitrate doses ranging from 4 to 19.5 mmol·day⁻¹ (248–1209 mg·day⁻¹) and durations from acute administration to 15 days. Positive effects were most frequently reported for cycling time-trial performance, Yo-Yo intermittent recovery performance, anaerobic power, neuromuscular performance, exercise tolerance, and recovery. In contrast, findings for endurance performance, sport-specific skills, oxygen consumption, and perceptual responses were inconsistent despite marked increases in nitrate and nitrite bioavailability. The outcomes seemed to depend on dosage, duration, sport type, and athletes’ training status. Conclusions: Beetroot-derived nitrate supplementation may enhance performance in highly trained and elite athletes, particularly during high-intensity and anaerobic activities. However, the effects are inconsistent, underscoring the need for further research to establish optimal supplementation strategies and evaluate long-term efficacy in elite sporting populations. Full article

Background/Objectives: Repeated sprint performance is typically reduced during the morning because of circadian-related changes in physiological function and muscle strength. Acute caffeine supplementation may attenuate these decrements; however, evidence remains inconsistent. This is partly because of inadequate control of chronobiological and methodological confounders. This study investigated the effects of acute morning caffeine ingestion on repeated sprint performance, physiological responses, strength, power and mood under rigorously standardized chronobiological conditions. Methods: Seventeen recreationally active, low habitual caffeine-consumer males completed six laboratory visits comprising three familiarization sessions and three experimental trials in a performance grouped, randomized for starting condition, counterbalanced, double-blind, placebo-controlled, crossover design. Participants ingested either caffeine (CAFF; 300 mg, 2.5–5.3 mg·kg⁻¹), placebo (PLAC) or no-pill control (NoPill) 60 min before testing (07:30 h). Experimental sessions included assessments of mood, caffeine withdrawal symptoms, intra-aural temperature, grip strength, squat jump, countermovement jump and a 10 × 20 m repeated sprint protocol. Heart rate, ratings of perceived exertion (RPE), thermal comfort, blood lactate and blood glucose were assessed throughout the protocol. Data were analyzed using repeated-measures general linear models. Results: Caffeine did not significantly improve repeated sprint performance compared with PLAC or NoPill, although a trend towards faster 20 m sprint times was observed (3.39 ± 0.19 s vs. 3.43 ± 0.18 s and 3.41 ± 0.19 s, respectively; p = 0.070). Caffeine significantly reduced RPE (p = 0.029) but did not alter heart rate, blood lactate, blood glucose, thermal comfort, intra-aural temperature, mood, sleepiness, caffeine withdrawal symptoms nor lower-body power outcomes. Conclusions: Acute morning ingestion of 300 mg caffeine reduced perceived exertion but did not produce a clear ergogenic effect on repeated sprint performance under rigorously standardized chronobiological conditions. These findings suggest that, in low habitual caffeine users, the central perceptual effects of caffeine are insufficient to overcome the physiological constraints limiting morning repeated sprint performance and highlight the importance of rigorous chronobiological standardization when evaluating nutritional ergogenic aids. Full article

Background and Objectives: Evidence on the acute ergogenic effects of caffeine in adolescent athletes remains limited. This systematic review quantified acute performance-related effects and summarised adverse-event reporting in this population. Methods: PubMed and Web of Science were searched from inception to 13 May 2026 and SPORTDiscus was additionally searched from inception to 15 July 2026 for placebo-controlled studies of acute, dose-defined caffeine ingestion in adolescent athletes aged 10–19 years. Paired Hedges’ g values were synthesised separately across six outcome domains using three-level random-effects models with CR2 cluster-robust inference. Risk of bias and certainty of evidence were assessed using RoB 2 and GRADE. Safety findings were summarised narratively. Results: Thirty-five studies were included, of which 32, representing a total of 726 participants, contributed 363 effect sizes. In the primary analysis, which excluded a priori a small number of extreme combat-sport count-test effects arising from implausibly small reported standard deviations (Hedges’ g > 3.0), caffeine produced a small favourable average effect on physical performance (g = 0.33, 95% CI 0.17 to 0.49). When all effect sizes were included in a sensitivity analysis, the estimate was larger but inflated by these extreme values (g = 0.43, 95% CI 0.20 to 0.67) and was accompanied by substantial heterogeneity (I² = 84%), a prediction interval crossing the null (−0.71 to 1.58), and significant small-study asymmetry. Pooled effects were not statistically significant for sport-specific performance, perceptual response, or physiology. Cognitive findings were based on only two study clusters and were highly uncertain, while psychological outcomes were summarised narratively because the evidence was too sparse and heterogeneous for a meaningful pooled estimate. Exploratory moderator analyses did not provide reliable evidence that effects differed by caffeine dose or ingestion timing. No serious adverse events were reported, but adverse-event assessment was inconsistent. Conclusions: Acute caffeine ingestion may produce a small and uncertain benefit for selected physical-performance tasks in adolescent athletes. Adverse-event reporting was inconsistent, and current evidence is insufficient to support routine caffeine use in youth sport. These findings are specific to acute caffeine exposure under controlled experimental conditions in adolescent athletes and should not be extrapolated to children, non-athlete adolescents, repeated or chronic caffeine use, or energy-drink consumption. Full article

Background and Objectives: Evidence on the acute effects of caffeine in female team-sport athletes is limited. This study aimed to quantify the acute effects of caffeine on female team-sport athletes across physical performance, sport-specific performance, physiological responses, perceptual responses, and cognitive performance and determine moderators. Methods: PubMed and Web of Science were systematically searched for randomized, placebo-controlled crossover trials of acute, dose-defined caffeine in female team-sport athletes. Effect sizes were expressed as Hedges’ g and synthesized within each domain using a three-level CHE model with CR2 cluster-robust variance estimation and Satterthwaite degrees of freedom; 95% confidence intervals and prediction intervals were reported. Risk of bias (RoB 2), methodological quality (PEDro), and certainty of evidence (GRADE) were assessed. Results: Twenty-six studies were included, comprising 26 randomized, blind, placebo-controlled crossover trials. As a descriptive cross-domain summary, acute caffeine intake showed a small overall effect when all available domains were pooled (Hedges’ g = 0.24, 95% CI 0.13 to 0.35); however, because these domains represent different constructs, domain-specific estimates were considered the primary interpretable findings. For physical performance, caffeine showed a small favorable effect (g = 0.32, 95% CI 0.22 to 0.42), with statistical evidence for repeated sprint ability (g = 0.43), agility or change in direction (g = 0.42), sprint or speed performance (g = 0.39), anaerobic power (g = 0.30), and jumping performance (g = 0.29). For sport-specific performance, the pooled estimate indicated a small favorable effect but did not reach conventional statistical significance (g = 0.36, 95% CI: −0.01 to 0.73). Exploratory sub-indicator analyses, each based on only a few studies, suggested possible favorable directions for sport-specific locomotion or running performance (g = 0.46) and throwing or ball-speed outcomes (g = 0.19), whereas evidence was insufficient for shooting or scoring accuracy. Physiological outcomes were direction-aligned to the value conventionally regarded as favourable for each indicator (i.e., lower heart rate, lactate, and glucose), so that positive values denote the conventionally favourable direction; because the domain aggregates indicators of differing clinical desirability, its pooled value is a descriptive summary only and showed no clear domain-level direction (g = −0.05, 95% CI −0.31 to 0.21). The heart rate submetric showed a statistically detectable difference (g = −0.30), indicating that caffeine increased heart rate, the expected pharmacological response to a stimulant rather than an adverse effect; there were no clear effects on blood lactate or blood glucose. Perceptual responses improved modestly (g = 0.42), largely through reduced rating of perceived exertion (g = 0.35). Cognitive performance, based on only four studies with low degrees of freedom and wide uncertainty, showed a nonsignificant direction (g = 0.37) with no clear evidence for reaction time or cognitive accuracy, and these data should not be interpreted as showing that caffeine improves cognitive performance in female team-sport athletes. Exploratory moderator analyses did not provide statistically reliable evidence of moderation by caffeine dose, timing of intake, formulation or source, sport type, competitive level, habitual caffeine intake, or blinding status. Conclusions: Available evidence most consistently supports small, outcome-specific benefits of acute caffeine for physical performance and reduced perceived exertion. Evidence for sport-specific skills and cognitive outcomes remained uncertain, based on few studies per outcome and not supporting a general benefit. Current data do not support dose-, timing-, formulation-, habitual-intake-, sport-, or population-stratified recommendations. Future trials should be adequately powered, prospectively report menstrual-cycle phase, hormonal-contraceptive use, habitual caffeine intake, and adverse symptoms, and verify the integrity of blinding. Full article

High-intensity exercise performance is a complex phenomenon that emerges from the interaction of neuromuscular, metabolic, molecular, and biomechanical systems. While previous research has primarily examined these factors independently, a comprehensive understanding requires an integrative perspective. Therefore, this narrative review aimed to synthesize current evidence and conceptualize high-intensity exercise performance as a complex adaptive system. The review examined the effects of different training modalities, including high-intensity interval training, sprint training, resistance training, plyometric training, and concurrent training, alongside neuromuscular regulation, molecular adaptations, fatigue mechanisms, and ergogenic aids. Evidence indicates that performance improvements result from coordinated interactions among training-induced adaptations, intracellular signaling pathways, and physiological responses. Furthermore, ergogenic aids such as caffeine, creatine, beta-alanine, and dietary nitrates may enhance performance when appropriately aligned with training demands. Overall, high-intensity exercise performance should be viewed as an emergent property of interconnected physiological systems rather than the product of isolated mechanisms. This systems-based framework provides a comprehensive perspective for understanding and optimizing athletic performance. Full article

Exogenous ketone supplementation has emerged as a potential ergogenic strategy for trained and physically active individuals, prompting increasing research into its effects on exercise performance and metabolism. This systematic review evaluated the effects of ketone supplementation on athletic performance, metabolic variables, and physiological responses in trained and physically active populations. Searches were conducted in EBSCOhost, PubMed, and Web of Science following PRISMA 2020 guidelines. Peer-reviewed controlled studies published between 2018 and December 2025 were included. Twenty-six studies met the eligibility criteria. Ketone supplementation consistently increased circulating β-hydroxybutyrate concentrations and modified glucose, lactate, and acid–base balance. Effects on exercise performance were heterogeneous, with some studies reporting improvements in time-trial performance and cognitive function, whereas others found no benefit or even impaired performance. Co-ingestion with sodium bicarbonate attenuated metabolic acidosis and occasionally enhanced performance outcomes. Ketone supplementation also influenced cardiorespiratory responses and fluid regulation, and may promote muscular angiogenesis during periods of training overload. Overall, current evidence remains heterogeneous and does not support definitive conclusions regarding ergogenic efficacy, which appears to depend on exercise intensity, participant characteristics, supplementation protocols, and co-ingestion strategies. Full article

Caffeine is among the most widely used supplements in sports nutrition, with substantial evidence supporting its efficacy for enhancing athletic performance. However, the relevance of pre-exercise caffeine supplementation extends beyond its ergogenic effects. Exercise itself acts as an acute cardiometabolic stressor, eliciting dynamic responses in blood pressure, heart rate, vascular tone, substrate utilization, and glucose regulation. Caffeine may further modify the magnitude, temporal profile, and recovery kinetics of these responses. This focused narrative review examines the acute cardiometabolic responses associated with pre-exercise caffeine supplementation and its potential regulatory effects. It outlines the underlying biological mechanisms, including adenosine receptor antagonism, hemodynamic and vascular pathways, and metabolic and substrate-utilization pathways, while synthesizing current evidence from the literature. Available evidence indicates that the acute effects of caffeine are highly context dependent. In some exercise settings, caffeine may promote lipolysis and fat oxidation; in others, particularly among susceptible individuals or under specific exercise conditions, it may be associated with greater acute cardiovascular or autonomic load, reflected by higher peripheral vascular resistance and blood pressure, altered vascular reactivity, or delayed post-exercise autonomic recovery. Its effects may vary according to dose, timing, supplement form, exercise modality and intensity, training status, habitual caffeine intake, genotype, sex, and hormonal status. Overall, pre-exercise caffeine should not be regarded solely as a uniformly beneficial ergogenic aid, but rather as a physiological modulator that may reshape the acute cardiometabolic milieu during and after exercise. Future studies should integrate hemodynamic, vascular, metabolic, and individual-variability measures over extended observation periods to support more evidence-based and individualized guidance on the appropriate use of pre-exercise caffeine. Full article

Background/Objectives: Caffeine is a widely used ergogenic aid; however, evidence regarding its effects on neuromuscular and metabolic responses during resistance training remains limited. Therefore, this study aimed to analyze the effects of caffeine supplementation on blood glucose concentration and neuromuscular activation, assessed through electromyographic activity, during a muscular endurance test. Methods: Eleven resistance-trained men (25.7 ± 5.9 years) participated in this randomized, double-blind, crossover trial. Six laboratory visits were conducted, including one-repetition maximum (1RM) and maximal voluntary isometric contraction (MVIC) testing in the bench press exercise. From the second visit onward (baseline; BL), participants completed a 24 h dietary recall (24hDR), pre- and post-exercise blood glucose assessments, and a muscular endurance test performed at 80% of 1RM until concentric failure, while electromyographic activity was recorded from the clavicular and sternal portions of the pectoralis major, triceps brachii, and anterior deltoid. From the third visit onward, participants received one of the following randomized interventions 60 min before testing: low-dose caffeine (LC = 3 mg·kg⁻¹), high-dose caffeine (HC = 6 mg·kg⁻¹), low-dose placebo (LP = 230 mg), or high-dose placebo (HP = 460 mg). Results: There was an increase in the number of repetitions in all conditions vs. BL, with no significant differences (p > 0.05). Electromyographic activity did not differ between conditions (p > 0.05). Blood glucose decreased post-test in BL and placebo conditions (p < 0.05) but remained stable with caffeine (p > 0.05). Conclusions: Low and high doses of caffeine did not significantly affect muscular endurance performance or neuromuscular activation. However, caffeine supplementation appeared to attenuate the post-exercise decline in blood glucose concentration following exercise performed to concentric failure. Full article

Background/Objectives: Caffeinated chewing gum is a practical, rapidly absorbed ergogenic aid increasingly used in team sports, yet its interaction with different small-sided soccer game (SSG) formats in young male players remains unclear. This study evaluated the effects of acute caffeinated (CAF) chewing gum on psychophysiological responses and kinematic profiles during intermittent (INT) and continuous (CON) 3-a-side SSGs. Methods: Twenty-four young male soccer players (18.4 ± 0.5 years) completed four 3-a-side SSG sessions separated by 48 h in a randomized, double-blind, placebo (PLA)-controlled, crossover design (CAF-INT, PLA-INT, CAF-CON, PLA-CON). Participants chewed 300 mg of CAF or PLA gum for 5 min, with mastication completed 5 min before warm-up session. The heart rates and kinematic profiles were recorded during the SSGs, and the ratings of perceived exertion (RPE), exercise enjoyment scale (EES), and visual analogue scale (VAS) to perceived mental fatigue (MF) were assessed post-game. Results: Compared with the PLA, the CAF increased the heart rate responses (HR), EES, total distance (TD), player load (PL), acceleration (ACC), and distances covered in selected speed zones (from Z0 to Z5), while reducing the RPE and MF. Significant format × supplementation interactions indicated that CAF-induced changes in high-intensity kinematic outcomes (TD, PL, ACC, Z2–Z5) and HR responses (HR_mean, HR_max) were generally greater in INT, whereas CAF-induced increases in low-intensity running distances (Z0 and Z1) and %HR_max were more pronounced in the CON format (all p < 0.05 for the reported effects; ${\eta }_p^2$ = 0.16–0.93 for CAF main effects [large effects]). The EES improvements were more pronounced in the CON format, whereas the MF and RPE reductions were more pronounced in the INT format. Conclusions: CAF chewing gum may be a practical acute strategy for modulating psychophysiological responses and kinematic profiles during SSGs, with the effects depending partly on the game format. Full article

Paralympic Powerlifting is a maximal strength sport that requires high training intensity and efficient recovery to maintain performance and prevent injury. Intense training can induce oxidative stress, potentially compromising performance and physiological adaptation. Caffeine (CA) is a widely used ergogenic aid with potential to enhance muscle strength and reduce oxidative damage. This study investigated the acute effects of CA supplementation (9 mg/kg) on static strength indicators and oxidative stress markers in 14 male Paralympic powerlifting athletes. The protocol included two conditions (CA and placebo), with athletes performing 5 sets of 5 repetitions at 80% of 1 RM in the adapted bench press. Strength variables (maximal isometric force, 1-s peak force, and force variability) and biomarkers (TBARS/MDA, total antioxidant capacity, sulfhydryl groups, and uric acid) were analyzed. CA supplementation significantly increased maximal isometric strength, improved 1-s peak force, and reduced variability, suggesting enhanced motor unit recruitment. However, CA also led to increased oxidative stress, as evidenced by elevated TBARS levels, reduced antioxidant capacity, decreased sulfhydryl groups, and higher uric acid concentrations post-exercise. In conclusion, while CA acutely improves neuromuscular performance, it does not attenuate—and may even exacerbate—exercise-induced oxidative stress. Therefore, its use in strength sports should be approached with caution. Full article

Background: New Zealand blackcurrant (NZBC) is an anthocyanin-rich supplement with reported ergogenic effects in endurance exercise; however, its effects in resistance-trained adults remain largely unexplored. Objective: This study aimed to examine whether seven days of low- or high-dose NZBC supplementation improves resistance exercise performance, anaerobic capacity, and cognitive function in resistance-trained adults. Methods: Twenty resistance-trained adults completed a randomized, double-blind, placebo-controlled crossover trial with four conditions: no-capsule control (CON), placebo (PL), low-dose blackcurrant (LDBC; 250 mg·day⁻¹), and high-dose blackcurrant (HDBC; 600 mg·day⁻¹), each for seven days. Outcomes included bench press and leg press 1RM, total lifting volume, Tendo-derived bench press power, 30 s Wingate performance, Stroop Color–Word Test scores, readiness, perceived exertion, hemodynamic responses, and adverse events. Results: LDBC and HDBC increased bench press 1RM versus CON and PL, with increases versus CON of +3.33 kg (ES = 0.72; p = 0.005) and +2.34 kg (ES = 0.49; p = 0.041), respectively. Leg press 1RM was higher in PL, LDBC, and HDBC versus CON, with the largest effects observed for LDBC (+37.2 kg, ES = 1.33; p < 0.001) and HDBC (+25.8 kg, ES = 1.11; p < 0.001). Leg press total lifting volume was substantially higher with LDBC (+2627 kg, ES = 1.56; p < 0.001) and HDBC (+1025 kg, ES = 0.74; p = 0.004) versus CON. Bench press volume showed no significant overall treatment effect (p > 0.05). For Tendo-derived power, HDBC exceeded PL for peak (+79.5 W; p = 0.006) and mean power (+46.2 W; p = 0.026). Wingate outcomes did not differ across conditions (all p > 0.05). LDBC exceeded PL on Stroop Color, Color–Word, and total scores (all p < 0.05); HDBC exceeded PL on Color–Word only. Hemodynamic responses and adverse events were comparable across all conditions. Conclusions: Short-term NZBC supplementation improved selected resistance-exercise and cognitive outcomes, with the strongest evidence observed for outcomes that exceeded both CON and PL. The PL response relative to CON suggests that non-specific capsule, expectancy, repeated testing, or period effects may have contributed to some of the lower-body improvements; therefore, placebo-controlled contrasts should be emphasized when interpreting NZBC-specific efficacy. Wingate performance was unaffected, and both doses were well tolerated over the short-term supplementation period. Full article