카페인 무수물

Effects of 3 mg/kg Body Mass of Caffeine on the Performance of Jiu-Jitsu Elite Athletes.

1. Nutrients. 2022 Feb 5;14(3):675. doi: 10.3390/nu14030675. Effects of 3 mg/kg Body Mass of Caffeine on the Performance of Jiu-Jitsu Elite Athletes. Merino-Fernández M(1), Giráldez-Costas V(2), González-García J(2), Gutiérrez-Hellín J(1), González-Millán C(1), Matos-Duarte M(1), Ruiz-Moreno C(

The Effects of Caffeine on Jumping Performance and Maximal Strength in Female Collegiate Athletes.

2. Nutrients. 2021 Jul 22;13(8):2496. doi: 10.3390/nu13082496. The Effects of Caffeine on Jumping Performance and Maximal Strength in Female Collegiate Athletes. Burke BI(1), Travis SK(1), Gentles JA(1), Sato K(2), Lang HM(3), Bazyler CD(1). Author information: (1)Center of Excellence for Sport

Effects of Creatine and Caffeine Supplementation During Resistance Training on Body Composition, Strength, Endurance, Rating of Perceived Exertion and Fatigue in Trained Young Adults.

3. J Diet Suppl. 2022;19(5):587-602. doi: 10.1080/19390211.2021.1904085. Epub 2021 Mar 24. Effects of Creatine and Caffeine Supplementation During Resistance Training on Body Composition, Strength, Endurance, Rating of Perceived Exertion and Fatigue in Trained Young Adults. Pakulak A(1), Candow

Effects of chronic caffeine pre-exposure on conditioned and unconditioned psychomotor activity induced by nicotine and amphetamine in rats.

4. Behav Pharmacol. 2003 May;14(3):191-8. doi: 10.1097/00008877-200305000-00002. Effects of chronic caffeine pre-exposure on conditioned and unconditioned psychomotor activity induced by nicotine and amphetamine in rats. Palmatier MI(1), Fung EY, Bevins RA. Author information: (1)Department of P

The Acute Effects of Caffeine and Normobaric Hypoxia on Cardiorespiratory Exercise Responses in Healthy Adults: A Randomized Controlled Trial.

1. Int J Sport Nutr Exerc Metab. 2025 Jul 15;35(5):385-393. doi: 10.1123/ijsnem.2025-0024. Print 2025 Sep 1. The Acute Effects of Caffeine and Normobaric Hypoxia on Cardiorespiratory Exercise Responses in Healthy Adults: A Randomized Controlled Trial. Narang BJ(1)(2), Štritof A(1), Debevec T(1)(2). Author information: (1)Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia. (2)Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia. The ergogenic effects of caffeine for endurance performance at sea level are well established. However, whether caffeine enhances exercise capacity or modulates cardiorespiratory responses in hypoxia remains unclear. Twenty-nine healthy, active volunteers (14 women) completed four tests in a pseudorandomized order, comprising 10 min of steady-state cycling (40% normoxic maximal aerobic power) followed by incremental exercise tests to exhaustion. Participants consumed 6 mg/kg body mass anhydrous caffeine, or placebo, 45 min before exercise. Tests were performed while breathing room air or a hypoxic gas mixture (simulating ∼3,500 m). At peak exercise intensity, oxygen uptake was affected by condition (hypoxia vs. normoxia; 44.8 ± 7.3 vs. 51.4 ± 7.9 ml·kg-1·min-1; p < .001) but not supplement (caffeine vs. placebo; 48.2 ± 8.2 vs. 48.0 ± 8.4 ml·kg-1·min-1; p = .501). Maximal aerobic power and pulse oxygen saturation were lower in hypoxia (both p < .001), but unaffected by caffeine (p = .061 and .898, respectively). Pulmonary ventilation was unaffected by hypoxia (p = .154) or caffeine (p = .117). Heart rate was higher in normoxia and with caffeine (both p < .001). During steady-state cycling, hypoxia (p < .001) and caffeine (p = .026) increased pulmonary ventilation. However, the hypoxia-induced pulse oxygen saturation decrease (p < .001) was not attenuated with caffeine (interaction p = .283). Perceived exertion was higher in hypoxia (p < .001) and lower with caffeine (p = .026). Caffeine increased vastus lateralis oxygenation in hypoxia (caffeine vs. placebo; 52 ± 8 vs. 50 ± 10%; p = .020) but not in normoxia (caffeine vs. placebo; 59 ± 7 vs. 59 ± 8%; p > .999). Overall, caffeine did not enhance exercise capacity in either environmental condition. However, during steady-state cycling, caffeine enhanced pulmonary ventilation, reduced perceived exertion, and mitigated hypoxia-induced muscle oxygenation reductions. DOI: 10.1123/ijsnem.2025-0024 PMID: 40675560 [Indexed for MEDLINE]

Effects of Multi-Ingredient Pre-Workout Supplement and Caffeine on Bench Press Performance: A Single-Blind Cross-Over Study.

2. Nutrients. 2022 Apr 22;14(9):1750. doi: 10.3390/nu14091750. Effects of Multi-Ingredient Pre-Workout Supplement and Caffeine on Bench Press Performance: A Single-Blind Cross-Over Study. Kruszewski M(1), Merchelski M(1), Kruszewski A(1), Tabęcki R(1), Aksenov MO(2)(3), Pągowski Ł(1). Author information: (1)Department of Physical Education, Józef Piłsudski Univesity of Physical Education in Warsaw, 00-809 Warszawa, Poland. (2)Department of Physical Education, Plekhanov Russian University of Economics, 36 Stremyanniy, 117997 Moscow, Russia. (3)Department of Physical Education, Banzarov Buryat State University Ulan Ude, 24a Smolina, 670000 Buryatia, Russia. The problem addressed in this study is the appropriateness of using different pre-training supplementation strategies and their ability to improve training performance and psychological measures. The aim of the study is the evaluation of the effectiveness of a multi-ingredient pre-workout supplement (MIPS) containing beta-alanine, L-citrulline malate, arginine alpha-ketoglutarate, L-taurine, L-tyrosine and caffeine compared to an exact dosage of anhydrous caffeine in bench press strength endurance, feeling scale (FS), felt arousal scale (FAS) and session rating of perceived exertion (sRPE). A group of fifteen resistance-trained males, weighing 83.92 ± 8.95 kg and having an average of 5.6 ± 3.38 years of training experience, tested their bench press 10 repetition maximum (79.01 ± 12.13). In a cross-over manner, they participated in two sessions where they were blinded to the order of supplementation they were given: either a MIPS including caffeine or caffeine alone. They completed the bench press strength endurance test with pre- and post-training psychological assessments containing FS, FAS and sRPE. Bench press repetition volume was greater after anhydrous caffeine than MIPS supplementation with no difference in psychological measures. These results indicate that MIPS supplementation is less ergogenic and cost effective than caffeine alone. DOI: 10.3390/nu14091750 PMCID: PMC9105861 PMID: 35565718 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflict of interest.

Effect of caffeine supplementation on exercise performance, power, markers of muscle damage, and perceived exertion in trained CrossFit men: a randomized, double-blind, placebo-controlled crossover trial.

3. J Sports Med Phys Fitness. 2020 Feb;60(2):181-188. doi: 10.23736/S0022-4707.19.10043-6. Epub 2019 Oct 25. Effect of caffeine supplementation on exercise performance, power, markers of muscle damage, and perceived exertion in trained CrossFit men: a randomized, double-blind, placebo-controlled crossover trial. Fogaça LJ(1), Santos SL(1), Soares RC(1), Gentil P(2), Naves JP(2), Dos Santos WD(2), Pimentel GD(1), Bottaro M(3), Mota JF(4). Author information: (1)Clinical and Sports Nutrition Research Laboratory (LABINCE), Faculty of Nutrition, Federal University of Goias, Goiania, Brazil. (2)College of Physical Education and Dance, Federal University of Goias, Goiania, Brazil. (3)College of Physical Education, University of Brasília, Campus Universitário Darcy Ribeiro, Brasilia, Brazil. (4)Clinical and Sports Nutrition Research Laboratory (LABINCE), Faculty of Nutrition, Federal University of Goias, Goiania, Brazil - jfemota@gmail.com. BACKGROUND: Caffeine is a popular nutritional supplement among athletes. It is frequently used as an ergogenic aid to improve physical performance, delay fatigue, and increase muscle power. However, these effects have not been tested in CrossFit athletes. The aim of this study was to evaluate the effects of acute caffeine supplementation on workout performance, power, markers of muscle damage, and soreness in trained CrossFit men. METHODS: Nine men (28±2 years) with experience in CrossFit (2±0.3 years) were investigated in a randomized, double-blind, placebo-controlled crossover trial, with a 7-day washout between treatment periods. The athletes received anhydrous caffeine (CAF: 6 mg/kg body mass) or placebo (PLA) 60 minutes before a CrossFit workout with tasks that involved muscle strength, power, gymnastic movements, and metabolic conditioning. Blood samples were collected for creatine kinase (CK), C-reactive protein, and glucose determination. Workout performance, rating of perceived exertion (RPE), delayed-onset muscle soreness (DOMS), muscle strength (handgrip strength) and power (bench throw, jump squat and countermovement jump) were also evaluated. RESULTS: CAF resulted in higher glucose concentration after workout compared to PLA (+3.2 mmol/L, 95% CI: 2.1 to 4.3 vs. +1.5, 95% CI: -0.1 to 3.0 mmol/L, P=0.01). No differences were found between treatments in workout performance, CK, DOMS, RPE, muscle power and strength. CONCLUSIONS: Acute CAF supplementation did not alter performance, markers of muscle damage, power, and RPE in trained CrossFit men. DOI: 10.23736/S0022-4707.19.10043-6 PMID: 31665873 [Indexed for MEDLINE]

Caffeine added to coffee does not alter the acute testosterone response to exercise in resistance trained males.

4. J Sports Med Phys Fitness. 2019 Sep;59(9):1435-1441. doi: 10.23736/S0022-4707.19.09183-7. Caffeine added to coffee does not alter the acute testosterone response to exercise in resistance trained males. Landry TM(1), Saunders MJ(1), Akers JD(2), Womack CJ(3). Author information: (1)Human Performance Laboratory, Department of Kinesiology, James Madison University, Harrisonburg, VA, USA. (2)Department of Health Professions, James Madison University, Harrisonburg, VA, USA. (3)Human Performance Laboratory, Department of Kinesiology, James Madison University, Harrisonburg, VA, USA - womackcx@jmu.edu. BACKGROUND: This study investigated the effects of coffee ingestion with supplemental caffeine (CAF) on serum testosterone (T) responses to exercise in recreationally strength-trained males. METHODS: Subjects ingested 6 mg/kg body weight of caffeine via 12 ounces of coffee (CAF) supplemented with anhydrous caffeine or decaffeinated (DEC) coffee prior to exercise in a randomized, within-subject, crossover design. The exercise session consisted of 21 minutes of high-intensity interval cycling (alternating intensities at power outputs associated with 2.0 mmol/L lactate for two minutes and 4.0 mmol/L lactate for one minute) followed by resistance exercise (seven exercises, three sets of ten repetitions, 65% 1RM, one-minute rest periods). Subjects also completed repetitions to fatigue tests and soreness scales to determine muscle recovery 24 hours following the exercise. RESULTS: T was elevated immediately and 30-minutes post-exercise by 20.5% and 14.3% respectively (P<0.05). There was no main effect for treatment and no exercise x treatment interaction. There were no differences in repetitions to fatigue or soreness between treatments (P>0.05). No relationships were observed between T and any proxy of recovery. CONCLUSIONS: While past literature suggests caffeine may enhance T post-exercise, data from the current study suggest that augmented T response is not evident following anhydrous caffeine added to coffee. The duration of T elevation indicates that this protocol is beneficial to creating long-lasting increases in serum testosterone. DOI: 10.23736/S0022-4707.19.09183-7 PMID: 31610637 [Indexed for MEDLINE]

Twelve weeks supplementation with an extended-release caffeine and ATP-enhancing supplement may improve body composition without affecting hematology in resistance-trained men.

5. J Int Soc Sports Nutr. 2016 Jun 10;13:25. doi: 10.1186/s12970-016-0136-9. eCollection 2016. Twelve weeks supplementation with an extended-release caffeine and ATP-enhancing supplement may improve body composition without affecting hematology in resistance-trained men. Joy JM(1), Vogel RM(1), Moon JR(2), Falcone PH(3), Mosman MM(4), Kim MP(3). Author information: (1)Department of Nutrition and Food Sciences, Texas Woman's University, 401 AME Drive #7101, Denton, TX 76207 USA. (2)American Public University System, School of Health Sciences, Charles Town, WV USA. (3)MusclePharm Sports Science Institute, MusclePharm Corp., Denver, CO USA. (4)Maximum Mobile Fitness, Spearfish, SD USA. BACKGROUND: Increased ATP levels may enhance training-induced muscle accretion and fat loss, and caffeine is a known ergogenic aid. A novel supplement containing ancient peat and apple extracts has reported enhanced mitochondrial ATP production and it has been coupled with an extended-release caffeine. Therefore, the purpose of this investigation was to determine the effects of this supplement on body composition when used in conjunction with 12 weeks of resistance training. METHODS: Twenty-one resistance-trained subjects (27.2 ± 5.6y; 173.5 ± 5.7 cm; 82.8 ± 12.0 kg) completed this study. Subjects supplemented daily with either 1 serving of the supplement (TRT), which consisted of 150 mg ancient peat and apple extracts, 180 mg blend of caffeine anhydrous and pterostilbene-bound caffeine, and 38 mg B vitamins, or an equal-volume, visually-identical placebo (PLA) 45 min prior to training or at the same time of day on rest days. Supervised resistance training consisted of 8 weeks of daily undulating periodized training followed by a 2-week overreach and a 2-week taper phase. Body composition was assessed using DEXA and ultrasound at weeks 0, 4, 8, 10, and 12. Vital signs and blood markers were assessed at weeks 0, 8, and 12. RESULTS: Significant group x time (p < 0.05) interactions were present for cross-sectional area of the rectus femoris, which increased in TRT (+1.07 cm(2)) versus PLA (-0.08 cm(2)), as well as muscle thickness (TRT: +0.49 cm; PLA: +0.04 cm). A significant group x time (p < 0.05) interaction existed for creatinine (TRT: +0.00 mg/dL; PLA: +0.15 mg/dL) and estimated glomerular filtration rate (TRT: -0.70 mL/min/1.73; PLA: -14.6 mL/min/1.73), which remained within clinical ranges, but no other significant observations were observed. CONCLUSIONS: Supplementation with a combination of extended-release caffeine and ancient peat and apple extracts may enhance resistance training-induced skeletal muscle hypertrophy without adversely affecting blood chemistry. DOI: 10.1186/s12970-016-0136-9 PMCID: PMC4901467 PMID: 27293386 [Indexed for MEDLINE]

Acute effectiveness of a "fat-loss" product on substrate utilization, perception of hunger, mood state and rate of perceived exertion at rest and during exercise.

6. J Int Soc Sports Nutr. 2015 Nov 25;12:44. doi: 10.1186/s12970-015-0105-8. eCollection 2015. Acute effectiveness of a "fat-loss" product on substrate utilization, perception of hunger, mood state and rate of perceived exertion at rest and during exercise. Alkhatib A(1), Seijo M(2), Larumbe E(3), Naclerio F(2). Author information: (1)Division of Sport and Exercise Science, School of Social and Health Sciences, University of Abertay, Bell Street, Dundee City, DD1 1HG United Kingdom. (2)Centre for Sport Science and Human Performance, School of Science, University of Greenwich, Medway Campus, Central Avenue, Chatham Maritime, Kent, ME4 4TB London, United Kingdom. (3)Clinical Research Institute, Texas Tech University Health Sciences Center, Lubbock, TX USA. BACKGROUND: Achieving fat-loss outcomes by ingesting multi-ingredient mixtures may be further enhanced during exercise. This study tested the acute thermogenic effectiveness of a commercially available multi-ingredient product (Shred-Matrix®), containing Green Tea Extract, Yerba Maté, Guarana Seed Extract, Anhydrous caffeine, Saw palmetto, Fo-Ti, Eleuthero root, Cayenne Pepper, and Yohimbine HCI, on fatty acid oxidation (FAO), perception of hunger, mood state and rate of perceived exertion (RPE) at rest and during 30 min of submaximal exercise. METHODS: Following institutional ethical approval, twelve healthy recreationally active participants, five females and seven males, were randomized to perform two separate experimental ergometry cycling trials, and to ingest 1.5 g (3 × capsules) of either a multi-ingredient supplement (SHRED) or placebo (PL). Participants rested for 3 h, before performing a 30-min cycling exercise corresponding to their individually-determined intensity based on their maximal fat oxidation (Fatmax). Fatty acid oxidation (FAO) was determined at rest, 3 h before exercise (Pre1), immediately before exercise (Pre2) and during exercise (Post), using expired gasses and indirect calorimetry. Rate of perceived exertion (RPE) was measured every 3 min during the 30-min exercise. Additionally both mood state and perception of hunger were assessed at Pre1, Pre2 and Post exercise. A repeated measures ANOVA design and Cohen's d effect sizes were used to analyze potential differences between times and treatment conditions. RESULTS: FAO increased in SHRED from Pre1 to Pre2 [0.56 ± 0.26 to 0.96 ± 0.37, (p = 0.003, d =1.34)] but not in PL [0.67 ± 0.25 to 0.74 ± 0.19, (p = 0.334) d = 0.49], with no differences were found between conditions (p = 0.12, d = 0.49). However, Cohen's d = 0.77 revealed moderate effect size in favor of SHRED from Pre to Post exercise. RPE values were lower in SHRED compared to Pl (p< 0.001). Mood state and perception of hunger were not different between conditions, with no interaction effects. However, a trend was shown towards improved satiety in SHRED compared with PL, [F(1,11) = 3.58, p = 0.085]. CONCLUSIONS: The multi-ingredient product's potential enhancement of FAO during exercise, satiety, and RPE reduction suggests an acute effectiveness of SHRED in improving the exercise-related fat loss benefits. DOI: 10.1186/s12970-015-0105-8 PMCID: PMC4660661 PMID: 26612980 [Indexed for MEDLINE]

Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading.

7. J Strength Cond Res. 2016 May;30(5):1438-46. doi: 10.1519/JSC.0000000000001223. Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading. Trexler ET(1), Smith-Ryan AE, Roelofs EJ, Hirsch KR, Persky AM, Mock MG. Author information: (1)1Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina; 2Human Movement Sciences, Department of Allied Health Sciences, University of North Carolina, Chapel Hill, North Carolina; and 3School of Pharmacy, Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina, Chapel Hill, North Carolina. The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ≤ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ≤ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ≤ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA. DOI: 10.1519/JSC.0000000000001223 PMCID: PMC4808512 PMID: 26439785 [Indexed for MEDLINE]

Effects of an Acute High Dose of Caffeine on Physiological Responses and Performance During a Strength-Focused CrossFit(®) Workout: A Randomized, Double-Blind, Crossover Study.

8. Nutrients. 2025 Apr 23;17(9):1419. doi: 10.3390/nu17091419. Effects of an Acute High Dose of Caffeine on Physiological Responses and Performance During a Strength-Focused CrossFit(®) Workout: A Randomized, Double-Blind, Crossover Study. Konidari Z(1), Smilios I(1), Mougios V(2), Bogdanis GC(3). Author information: (1)Department of P.E. and Sport Science, Democritus University of Thrace, 69132 Komotini, Greece. (2)Laboratory of Evaluation of Human Biological Performance, School of P.E. and Sport Science at Thessaloniki, Aristotle University of Thessaloniki, 57001 Thessaloniki, Greece. (3)Department of P.E. and Sport Science, National and Kapodistrian University of Athens, 17237 Athens, Greece. Background: Several nutritional strategies have been used to enhance performance in CrossFit® training. This randomized, double-blind, crossover study aimed to investigate the acute effects of caffeine consumption on physiological responses and performance during a strength-focused CrossFit workout. Methods: Twelve healthy men, aged 29.2 ± 3.8 years (mean ± SD throughout), with 4.9 ± 1.9 years of CrossFit experience, completed two sessions of a specific CrossFit training program (four rounds of five exercises, 50 s exercise/10 s rest), 60 min after consuming either anhydrous caffeine (7.1 ± 0.7 mg/kg of body mass) or a placebo, aiming to perform as many repetitions as possible. The washout period was at least seven days. At the end of each round, subjective perception of fatigue was recorded using the Borg scale. Blood lactate concentration was measured before and immediately after completing the training session using a portable lactate analyzer. Data were analyzed by factorial ANOVA with repeated measures. Results: Caffeine had a negative effect on the number of sit-up repetitions in the fourth round (p = 0.012), while it did not affect any other performance parameter, rating of perceived exertion, or lactate concentration compared with the placebo. Conclusions: The results of the present study suggest that caffeine consumption does not improve performance in CrossFit training. DOI: 10.3390/nu17091419 PMCID: PMC12073388 PMID: 40362728 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflicts of interest.

Are caffeine effects equivalent between different modes of administration: the acute effects of 3 mg.kg(-1) caffeine on the muscular strength and power of male university Rugby Union players.

9. J Int Soc Sports Nutr. 2024 Dec;21(1):2419385. doi: 10.1080/15502783.2024.2419385. Epub 2024 Oct 22. Are caffeine effects equivalent between different modes of administration: the acute effects of 3 mg.kg(-1) caffeine on the muscular strength and power of male university Rugby Union players. Tallis J(1), Duncan MJ(1), Clarke ND(2), Morris RO(1), Tamilio RA(1)(3). Author information: (1)Coventry University, Centre for Physical Activity, Sport & Exercise Science, Coventry, UK. (2)Birmingham City University, Research Centre for Life and Sport Science (CLaSS), School of Health Sciences, Birmingham, UK. (3)University of Birmingham, School of Pharmacy, School of Health Sciences, College of Medicine and Health, Birmingham, UK. BACKGROUND: There is growing interest in the potential of alternative modes of caffeine administration for enhancing sports performance. Given that alternative modes may evoke improved physical performance via distinct mechanisms, effects may not be comparable and studies directly comparing the erogenicity of alternative modes of caffeine administration are lacking. To address this knowledge gap, the present study evaluated the effect of 3 mg·kg-1 caffeine delivered in anhydrous form via capsule ingestion, chewing gum or mouth rinsing on measures of muscular strength, power, and strength endurance in male Rugby Union players. METHODS: Twenty-seven participants completed the study (Mean ± SD: Age 20 ± 2 yrs; daily caffeine consumption 188 ± 88 mg). Following assessments and reassessment of chest press (CP), shoulder press (SP), Deadlift (DL), and Squat (SQ) 1-repetition maximum (1RM) and familiarization to the experimental procedures, participants completed six experimental trials where they were administered 3 mg.kg-1 caffeine (Caff) or placebo (Plac) capsule(CAP), chewing gum(GUM) or mouth rinse(RINSE) in a randomized, double-blind and counterbalanced fashion prior to force platform assessment of countermovement jump, drop jump and isometric mid-thigh pull performance. Strength endurance was measured across two sets of CP, SP, DL, and SQ at 70% 1RM until failure. Pre-exercise perceptions of motivation and arousal were also determined. RESULTS: Caffeine increased perceived readiness to invest mental effort (p = .038; ηp2=.156), countermovement jump height (p = .035; ηp2=.160) and SQ repetitions until failure in the first set (p < .001; d = .481), but there was no effect of delivery mode (p > .687; ηp2<.015). Readiness to invest physical effort, felt arousal, drop jump height, countermovement jump, drop jump and isometric mid-thigh pull ground reaction force-time characteristics and repetitions until failure in CP, SP and DL were not affected by caffeine administration or mode of caffeine delivery (p > .0.052; ηp2< .136). CONCLUSION: 3 mg.kg-1 caffeine administered via capsule, gum or mouth rinse had limited effects on muscular strength, power, and strength endurance. Small effects of caffeine on CMJ height could not be explained by changes in specific ground reaction force-time characteristics and were not transferable to DJ performance, and effects specific to the SQ RTP exercise underpin the complexity in understanding effects of caffeine on muscular function. Novel modes of caffeine administration proposed to evoke benefits via distinct mechanisms did not offer unique effects, and the small number of effects demonstrated may have little translation to a single performance trial when data examining direct comparison of each caffeine vehicle compared against a mode matched placebo is considered. DOI: 10.1080/15502783.2024.2419385 PMCID: PMC11500557 PMID: 39439175 [Indexed for MEDLINE] Conflict of interest statement: No potential conflict of interest was reported by the author(s).

Impact of CYP1A2 Genotypes on the Ergogenic Effects and Subjective Mood States of Caffeine Ingestion in Resistance-Trained Women.

10. Nutrients. 2024 Aug 20;16(16):2767. doi: 10.3390/nu16162767. Impact of CYP1A2 Genotypes on the Ergogenic Effects and Subjective Mood States of Caffeine Ingestion in Resistance-Trained Women. Prather JM(1), Florez CM(2), Vargas A(3), Soto B(3), Ross A(3), Harrison A(3), Secrest AH(4), Willoughby DS(5)(6), Kutter S(5), Taylor LW(3)(7). Author information: (1)Department of Health and Human Performance, Concordia University Chicago, River Forest, IL 60305, USA. (2)Energy Balance & Body Composition Laboratory, Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX 79409, USA. (3)Human Performance Lab, School of Exercise & Sport Science, University of Mary Hardin-Baylor, Belton, TX 76513, USA. (4)Public Health Program, School of Health Professions, University of Mary Hardin-Baylor, Belton, TX 76513, USA. (5)Physician Assistant Program, School of Health Professions, University of Mary Hardin-Baylor, Belton, TX 76513, USA. (6)School of Medicine, Baylor College of Medicine, Temple, TX 76508, USA. (7)Physical Therapy Program, School of Health Professions, University of Mary Hardin-Baylor, Belton, TX 76513, USA. Caffeine's metabolism is determined by CYP1A2 genotypes: AC/CC (SLOW) and AA (FAST). This trial evaluated CYP1A2 genotypes' impact on exercise and cognitive effects in 36 resistance-trained females assessed under placebo (PL) and caffeine (6 mg/kg bw anhydrous caffeine-CAF) conditions, before ingestion and throughout the session. 23andMe® (San Francisco, CA, USA) determined genotypes using saliva. Data were analyzed using two-way RMANOVA and paired-samples t-tests (p < 0.05). A significant main effect for genotype existed for leg press repetitions to failure (RTF) for CAF (p = 0.038), with the FAST group performing more repetitions than the SLOW (p = 0.027). There was a significant condition x genotype interaction for the subjective outcome index score (p = 0.045), with significant differences for time (p < 0.01) and between genotype (p < 0.001). Follow-up analysis revealed a higher total score (p = 0.028) following CAF for the FAST group and a lower total score (p < 0.01) in the SLOW group. Dizziness was reported following CAF in the SLOW group (p = 0.014; Cohen's d = 0.725). Aside from leg press RTF, subjective outcome index score, and dizziness, the genotype groups experienced similar responses to resistance exercise performance and subjective mood states following caffeine ingestion. DOI: 10.3390/nu16162767 PMCID: PMC11356906 PMID: 39203905 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflicts of interest.

Pharmacokinetic Profile of Caffeine and Its Two Main Metabolites in Dried Blood Spots After Five Different Oral Caffeine Administration Forms-A Randomized Crossover Study.

11. RETRACTED ARTICLE Int J Sport Nutr Exerc Metab. 2024 Jan 12;34(2):101-110. doi: 10.1123/ijsnem.2023-0141. Print 2024 Mar 1. Pharmacokinetic Profile of Caffeine and Its Two Main Metabolites in Dried Blood Spots After Five Different Oral Caffeine Administration Forms-A Randomized Crossover Study. Tuma C(1)(2), Thomas A(1), Trede L(1), Braun H(1)(2), Thevis M(1)(3). Author information: (1)Institute of Biochemistry/Center of Preventive Doping Research, German Sport University Cologne, Cologne, Germany. (2)German Research Centre of Elite Sports (momentum), German Sport University Cologne, Cologne, Germany. (3)European Monitoring Center for Emerging Doping Agents, Cologne/Bonn, Germany. Retraction in Int J Sport Nutr Exerc Metab. 2024 Sep 1;34(5):335. doi: 10.1123/ijsnem.2024-0140. Caffeine is an ergogenic substance that is consumed globally in many forms. The use of buccally absorbable formulations instead of gastrointestinal uptake has become increasingly popular over the years, especially when accelerated absorption with minimal gastrointestinal stress is desired. This study investigated the impact of five different formulations and administration routes of caffeine on the whole blood concentrations of caffeine, paraxanthine, and theobromine: caffeinated capsules, tablets, shots, pouches, and chewing gums. A uniform dose of caffeine (200 mg) was administered to 16 healthy recreational athletes (26.0 ± 2.1 years) using a randomized crossover design. Samples were taken in the form of dried blood spots at 16 different time points in a 2-hr timeframe after drug administration. The samples were analyzed using a validated liquid chromatography-tandem mass spectrometry method. The results for caffeine showed no significant differences in the overall bioavailability (area under the concentration-time curve), maximal concentration, and time to maximum concentration. However, when analyzing the bioavailability of caffeine in the first 5, 10, and 15 min, the liquid caffeine formulation was superior to other administered forms (p < .05). This indicates that caffeine solubility has a major influence on its absorption rate. In sports, the rate of caffeine absorption must be considered, not only when ingesting anhydrous caffeine, but also when choosing buccal absorption. These findings imply that general guidelines for ergogenic caffeine use should consider the formulation used and, accordingly, the corresponding route of absorption. DOI: 10.1123/ijsnem.2023-0141 PMID: 38215733 [Indexed for MEDLINE]

Effects of Different Doses of Caffeinated Coffee on Muscular Endurance, Cognitive Performance, and Cardiac Autonomic Modulation in Caffeine Naive Female Athletes.

12. Nutrients. 2020 Dec 22;13(1):2. doi: 10.3390/nu13010002. Effects of Different Doses of Caffeinated Coffee on Muscular Endurance, Cognitive Performance, and Cardiac Autonomic Modulation in Caffeine Naive Female Athletes. Karayigit R(1), Naderi A(2), Akca F(1), Cruz CJGD(3), Sarshin A(4), Yasli BC(5), Ersoz G(1), Kaviani M(6). Author information: (1)Faculty of Sport Sciences, Ankara University, Gölbaşı, Ankara 06830, Turkey. (2)Department of Sport Physiology, Boroujerd Branch, Islamic Azad University, Boroujerd 6915136111, Iran. (3)Laboratory of Exercise Physiology, Faculty of Physical Education, University of Brasilia, Brasilia 70910-900, Brazil. (4)Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Karaj Branch 3149968111, Iran. (5)Department of Physical Education and Sports, Iğdır University, Igdir 76000, Turkey. (6)Faculty of Pure & Applied Science, School of Nutrition and Dietetics, Acadia University, Wolfville, NS B4P 2R6, Canada. Caffeine is widely consumed among elite athletes for its well-known ergogenic properties, and its ability to increase exercise performance. However, studies to date have predominantly focused on the anhydrous form of caffeine in male participants. The aim of the study was to investigate the effect of caffeinated coffee ingestion on lower-upper body muscular endurance, cognitive performance, and heart rate variability (HRV) in female athletes. A total of 17 participants (mean ± standard deviation (SD): age = 23 ± 2 years, body mass = 64 ± 4 kg, height = 168 ± 3 cm) in a randomized cross-over design completed three testing sessions, following the ingestion of 3 mg/kg/bm of caffeine (3COF), 6 mg/kg/bm of caffeine (6COF) provided from coffee or decaffeinated coffee (PLA) in 600 mL of hot water. The testing results included: (1) repetition number for muscular endurance performance; (2): reaction time and response accuracy for cognitive performance; (3): HRV parameters, such as standard deviation of normal-to-normal (NN) intervals (SDNN), standard deviation of successive differences (SDSD), root mean square of successive differences (RMSSD), total power (TP), the ratio of low- and high-frequency powers (LF/HF), high-frequency power (HF), normalized HF (HFnu), low-frequency power (LF), and normalized LF (LFnu). A one-way repeated measures ANOVA revealed that 3COF (p = 0.024) and 6COF (p = 0.036) improved lower body muscular endurance in the first set as well as cognitive performance (p = 0.025, p = 0.035 in the post-test, respectively) compared to PLA. However, no differences were detected between trials for upper body muscular endurance (p = 0.07). Lastly, all HRV parameters did not change between trials (p > 0.05). In conclusion, ingesting caffeinated coffee improved lower body muscular endurance and cognitive performance, while not adversely affecting cardiac autonomic function. DOI: 10.3390/nu13010002 PMCID: PMC7821939 PMID: 33374947 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflict of interest.

Coffee Ingestion Improves 5 km Cycling Performance in Men and Women by a Similar Magnitude.

13. Nutrients. 2019 Oct 25;11(11):2575. doi: 10.3390/nu11112575. Coffee Ingestion Improves 5 km Cycling Performance in Men and Women by a Similar Magnitude. Clarke ND(1), Kirwan NA(1), Richardson DL(1). Author information: (1)School of Life Sciences, Faculty of Health and Life Sciences, Coventry University, Coventry CV12DS, UK. Caffeine is a well-established ergogenic aid, although research to date has predominantly focused on anhydrous caffeine, and in men. The primary aim of the present study was to investigate the effect of coffee ingestion on 5 km cycling time trial performance, and to establish whether sex differences exist. A total of 38 participants (19 men and 19 women) completed a 5 km time trial following the ingestion of 0.09 g·kg-1 coffee providing 3 mg·kg-1 of caffeine (COF), a placebo (PLA), in 300 mL of water, or control (CON). Coffee ingestion significantly increased salivary caffeine levels (p < 0.001; η P 2 = 0.75) and, overall, resulted in improved 5 km time trial performance (p < 0.001; η P 2 = 0.23). Performance following COF (482 ± 51 s) was faster than PLA (491 ± 53 s; p = 0.002; d = 0.17) and CON (487 ± 52 s; p =0.002; d = 0.10) trials, with men and women both improving by approximately 9 seconds and 6 seconds following coffee ingestion compared with placebo and control, respectively. However, no differences were observed between CON and PLA (p = 0.321; d = 0.08). In conclusion, ingesting coffee providing 3 mg·kg-1 of caffeine increased salivary caffeine levels and improved 5 km cycling time trial performance in men and women by a similar magnitude. DOI: 10.3390/nu11112575 PMCID: PMC6893638 PMID: 31731467 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflict of interest.

Women Experience the Same Ergogenic Response to Caffeine as Men.

14. Med Sci Sports Exerc. 2019 Jun;51(6):1195-1202. doi: 10.1249/MSS.0000000000001885. Women Experience the Same Ergogenic Response to Caffeine as Men. Skinner TL(1), Desbrow B(2)(3), Arapova J(1), Schaumberg MA(1)(4), Osborne J(1)(5), Grant GD(3)(6), Anoopkumar-Dukie S(3)(6), Leveritt MD(1). Author information: (1)School of Human Movement and Nutrition Sciences, The University of Queensland, Queensland, AUSTRALIA. (2)School of Allied Health Sciences, Griffith University, Queensland, AUSTRALIA. (3)Menzies Health Institute Queensland, Griffith University, Queensland, AUSTRALIA. (4)School of Health and Sports Sciences, University of the Sunshine Coast, Queensland, AUSTRALIA. (5)School of Exercise and Nutrition Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, AUSTRALIA. (6)Quality Use of Medicines Network, School of Pharmacy and Pharmacology, Griffith University, Queensland, AUSTRALIA. PURPOSE: This study aimed to determine whether 1) consumption of caffeine improves endurance cycling performance in women and 2) sex differences exist in the magnitude of the ergogenic and plasma responses to caffeine supplementation. METHODS: Twenty-seven (11 women and 16 men) endurance-trained cyclists and triathletes participated in this randomized, double-blind, placebo-controlled, crossover study. Participants completed an incremental exercise test to exhaustion, two familiarization trials, and two performance trials. Ninety minutes before the performance trials, participants ingested opaque capsules containing either 3 mg·kg body mass of anhydrous caffeine or a placebo. They then completed a set amount of work (75% of peak sustainable power output) in the fastest possible time. Plasma was sampled at baseline, preexercise, and postexercise for caffeine. Strict standardization and verification of diet, hydration, training volume and intensity, and contraceptive hormone phase (for women) were implemented. RESULTS: Performance time was significantly improved after caffeine administration in women (placebo: 3863 ± 419 s, caffeine: 3757 ± 312 s; P = 0.03) and men (placebo: 3903 ± 341 s, caffeine: 3734 ± 287 s; P < 0.001). The magnitude of performance improvement was similar for women (mean = 4.3%, 95% CI = 0.4%-8.2%) and men (4.6%, 2.3%-6.8%). Plasma caffeine concentrations were similar between sexes before exercise, but significantly greater in women after exercise (P < 0.001). CONCLUSIONS: Ingestion of 3 mg·kg body mass of caffeine enhanced endurance exercise performance in women. The magnitude of the performance enhancement observed in women was similar to that of men, despite significantly greater plasma caffeine concentrations after exercise in women. These results suggest that the current recommendations for caffeine intake (i.e., 3-6 mg·kg caffeine before exercise to enhance endurance performance), which are derived almost exclusively from studies on men, may also be applicable to women. DOI: 10.1249/MSS.0000000000001885 PMID: 30629046 [Indexed for MEDLINE]

Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men.

15. Eur J Sport Sci. 2017 Sep;17(8):1029-1036. doi: 10.1080/17461391.2017.1330362. Epub 2017 May 24. Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men. Grgic J(1), Mikulic P(2). Author information: (1)a Institute of Sport, Exercise and Active Living (ISEAL) , Victoria University , Melbourne , Australia. (2)b Faculty of Kinesiology , University of Zagreb , Zagreb , Croatia. The goal of this randomized, double-blind, cross-over study was to assess the acute effects of caffeine ingestion on muscular strength and power, muscular endurance, rate of perceived exertion (RPE), and pain perception (PP) in resistance-trained men. Seventeen volunteers (mean ± SD: age = 26 ± 6 years, stature = 182 ± 9 cm, body mass = 84 ± 9 kg, resistance training experience = 7 ± 3 years) consumed placebo or 6 mg kg-1 of anhydrous caffeine 1 h before testing. Muscular power was assessed with seated medicine ball throw and vertical jump exercises, muscular strength with one-repetition maximum (1RM) barbell back squat and bench press exercises, and muscular endurance with repetitions of back squat and bench press exercises (load corresponding to 60% of 1RM) to momentary muscular failure. RPE and PP were assessed immediately after the completion of the back squat and bench press exercises. Compared to placebo, caffeine intake enhanced 1RM back squat performance (+2.8%; effect size [ES] = 0.19; p = .016), which was accompanied by a reduced RPE (+7%; ES = 0.53; p = .037), and seated medicine ball throw performance (+4.3%, ES = 0.32; p = .009). Improvements in 1RM bench press were not noted although there were significant (p = .029) decreases in PP related to this exercise when participants ingested caffeine. The results point to an acute benefit of caffeine intake in enhancing lower-body strength, likely due to a decrease in RPE; upper-, but not lower-body power; and no effects on muscular endurance, in resistance-trained men. Individuals competing in events in which strength and power are important performance-related factors may consider taking 6 mg kg-1 of caffeine pre-training/competition for performance enhancement. DOI: 10.1080/17461391.2017.1330362 PMID: 28537195 [Indexed for MEDLINE]

Effects of Caffeine on Countermovement-Jump Performance Variables in Elite Male Volleyball Players.

16. Int J Sports Physiol Perform. 2018 Feb 1;13(2):145-150. doi: 10.1123/ijspp.2016-0705. Epub 2018 Jan 27. Effects of Caffeine on Countermovement-Jump Performance Variables in Elite Male Volleyball Players. Zbinden-Foncea H, Rada I, Gomez J, Kokaly M, Stellingwerff T, Deldicque L, Peñailillo L. PURPOSE: To examine the effects of a moderate dose of caffeine in elite male volleyball players on countermovement-jump (CMJ) performance, as well as temporal concentric- and eccentric-phase effects. METHODS: Ten elite male volleyball players took part in 2 experimental days via a randomized crossover trial 1 wk apart in which they ingested either 5 mg/kg of caffeine or a placebo in double-blind fashion. Heart rate and blood pressure were measured at rest and 60 min postingestion. Afterward, subjects also performed 3 CMJ trials 60 min postingestion, of which the average was used for further analysis. They filled out a questionnaire on possible side effects 24 h posttrial. RESULTS: Caffeine intake, compared with placebo, increased CMJ peak concentric force (6.5% ± 6.4%; P = .01), peak power (16.2% ± 8.3%; P < .01), flight time (5.3% ± 3.4%; P < .01), velocity at peak power (10.6% ± 8.0%; P < .01), peak displacement (10.8% ± 6.5%; P < .01), peak velocity (12.6% ± 7.4%; P < .01), peak acceleration (13.5% ± 8.5%; P < .01), and the force developed at peak power (6.0% ± 4.0%; P < .01) and reduced the time between peak power and peak force (16.7% ± 21.6%, P = .04). Caffeine increased diastolic blood pressure by 13.0% ± 8.9% (P < .05), whereas no adverse side effects were found. CONCLUSIONS: The ingestion of 5 mg/kg of anhydrous caffeine improves overall CMJ performance without inducing side effects. DOI: 10.1123/ijspp.2016-0705 PMID: 28488924 [Indexed for MEDLINE]