Article

The Acute Effects of a Caffeine-Containing Supplement on Strength, Muscular Endurance, and Anaerobic Capabilities

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Abstract

The purpose of this study was to examine the acute effects of a caffeine-containing supplement on upper- and lower-body strength and muscular endurance as well as anaerobic capabilities. Thirty-seven resistance-trained men (mean +/- SD, age: 21 +/- 2 years) volunteered to participate in this study. On the first laboratory visit, the subjects performed 2 Wingate Anaerobic Tests (WAnTs) to determine peak power (PP) and mean power (MP), as well as tests for 1 repetition maximum (1RM), dynamic constant external resistance strength, and muscular endurance (TOTV; total volume of weight lifted during an endurance test with 80% of the 1RM) on the bilateral leg extension (LE) and free-weight bench press (BP) exercises. Following a minimum of 48 hours of rest, the subjects returned to the laboratory for the second testing session and were randomly assigned to 1 of 2 groups: a supplement group (SUPP; n = 17), which ingested a caffeine-containing supplement, or a placebo group (PLAC; n = 20), which ingested a cellulose placebo. One hour after ingesting either the caffeine-containing supplement or the placebo, the subjects performed 2 WAnTs and were tested for 1RM strength and muscular endurance on the LE and BP exercises. The results indicated that there was a significant (p < 0.05) increase in BP 1RM for the SUPP group, but not for the PLAC group. The caffeine-containing supplement had no effect, however, on LE 1RM, LE TOTV, BP TOTV, PP, and MP. Thus, the caffeine-containing supplement may be an effective supplement for increasing upper-body strength and, therefore, could be useful for competitive and recreational athletes who perform resistance training.

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... This volume was based on the participants' training experience. It is also known that on average 80% of the 1RM applies to 2-5 repetition range [31]. Following an explanation of all procedures, risks and benefits associated with the study, each subject gave his written consent prior to participation. ...
... The average dosage of caffeine provided in this study was 3.4 mg·kg −1 . In other studies, where 1-RM bench press strength exercise was improved, the amount of caffeine in caffeine-containing supplement administrated was slightly lower (201 mg per dose = 2.4 mg·kg −1 ) [31]. However, the improvement in the study was around 2.1%, which is clearly lower than the strength improvement seen in the current study (7%), which could indicate a better chosen composition of additional active ingredients, which caused a better ergogenic synergistic effect of the of the MIPS investigated in this study. ...
... However, in many of these studies a number of pharmacologically active compounds were mixed together, so it is impossible to assess the effectiveness of each component separately. In this case, the effectiveness of each single ingredient remains unclear [31]. This is because multiple ingredients potentially interact and these interactions may potentiate or attenuate supplement effectiveness. ...
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Background: The purpose of this study was to investigate the acute effects of commercially available pre-workout supplement on anaerobic performance in resistance trained men. Methods: Twenty-three men underwent three testing sessions administrated in a randomized and double-blind fashion separated by a seven-day break. The participants performed three exercise tests: isokinetic strength test, maximal strength test and Wingate test. Statistical analysis was conducted in R environment. Linear mixed models were estimated via R package lme4. Results: The mean knee peak torque was significantly greater in supplemented group for right and left knee flexors (placebo: 103.17 ± 37.61 Nm, and supplemented group: 131.84 ± 29.31 Nm where p=0.001, and placebo: 103.72 ± 39.35, and supplemented group: 129.38 ± 28.44, where p=0.001; respectively) as well as for right and left knee extensors (placebo: 202.65 ± 58.64 Nm, and supplemented group: 237.22 ± 54.75 Nm where p=0.001, and placebo: 203.27 ± 63.2 Nm versus supplemented group: 229.84 ± 50.8 Nm where p=0.002; respectively).The significant difference was observed in mean anaerobic power between supplemented and placebo group for right and left knee flexors (p=0.002 and p=0.005, respectively) as well as for right and left knee extensors (p=0.001 and p=0.002; respectively).There was also observed that the time to peak torque was significantly greater in supplemented group for right and left knee flexors (p=0.002 for both legs). The significant difference was also observed in mean power between supplemented and placebo group during Wingate test (placebo: 8.49 ± 0.57 W/kg, and supplemented group: 8.66 ± 0.55 W/kg where p=0.038). Moreover the mean 3-RM strength test was significantly greater in supplemented group with p=0.001. Conclusions: The results of the study indicate that the supplement significantly improves upper and lower body strength and power output in resistance trained men.
... Caffeine (1,3,7-three methyl xanthine) is a member of methyl xanthine drugs and its one of the most commonly used drugs in the world (Teery et al., 1996). It absorbed quickly through intestine and metabolized in the liver then turns three species of dimethyl (Paraxanthine, theophylline, theobromine) that, they are maintained longer period than the caffeine in the blood and then generated their corresponding signals (Wilmore & Costill., 2005, Beck et al., 2006. Xanthine, such as caffeine, inhibits the phosphodiesterase which plays an T important role in the breakdown of cyclic adenosine 3 & 5-(cAMP) (Teery et al., 1996). ...
... Some studies have shown that caffeine improves short-term and power performance (Anselme et al., 1992, Beck et al., 2006, but some studies reported that this matter does not effect on the speed and power (Hendrix et al., 2010, Beck et al., 2006. In this context, Goldestein and colleagues (2010) examined the effects of caffeine (6mg / kg) one hour before training on endurance and strength upper body muscle in women with at least 6 months Precedent of resistance training and observed significant increase 1RM in the bench press (Goldestein et al., 2010). ...
... Some studies have shown that caffeine improves short-term and power performance (Anselme et al., 1992, Beck et al., 2006, but some studies reported that this matter does not effect on the speed and power (Hendrix et al., 2010, Beck et al., 2006. In this context, Goldestein and colleagues (2010) examined the effects of caffeine (6mg / kg) one hour before training on endurance and strength upper body muscle in women with at least 6 months Precedent of resistance training and observed significant increase 1RM in the bench press (Goldestein et al., 2010). ...
Article
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Ergogenic effects of caffeine on anaerobic maximal and submaximal peak performance, especially in resistance exercise is not clear. According to this, the purpose of this study was to investigate the acute effect of moderate amounts of caffeine on maximal strength, repetition sustainability and work volume in the upper and lower body of novice body builders. In a randomized double blind study, 15 male body builders' athletes (age of 21.16±3.9 years, height of 174.42±6.12 cm and weight of 73.25±6.71 kg) were examined. Exercise protocol was to test one repetition maximum (1RM) in the bench press and leg press and repetition sustainability of bench press and leg press with 80% 1RM in 5 sets. These tests were performed, one hour after ingesting caffeine (6 mg/kg) and placebo, in two separate sessions as similar. Muscle strength, sustainability of repetitions and volume of work (load × the number of repetitions) of upper and lower body were measured. To examine the differences between the effects of caffeine and placebo, t-test was used. The results showed that caffeine causes a significant increase in the strength of the upper and lower body (P<0.05). The repetition sustainability of upper and lower body in the first, second and third sets did not change significantly, but decreased significantly in the fourth and fifth sets. In addition, volume of work at the first to fifth set with consumption of caffeine in the body was significantly more than placebo (P<0.05). However, in the first and second set of lower body exercise was not observed significantly difference and meaningful difference was only seen in the third to fifth set between caffeine and placebo conditions (P<0.05). It seems that acute consumption of caffeine supplementation with ergogenic effect on maximal strength, sustainability of repetitions and the training volume in resistance exercise improve performance and possibly stimulate muscle for its development. Keywords
... 21 Jodra ve ark., kafein takviyesinin üst düzey sporcuların anaerobik performanslarını geliştirdiği bildirmesine karşın Beck ve ark., direnç antrenmanlı bireylerde kafeinin anaerobik kapasiteye etkisi olmadığını belirtmişlerdir. 22,23 Birçok araştırmacı, kafeinin çeşitli egzersiz performanslarında ergojenik yardımcı olduğu konusunda hem fikirdir. [24][25][26][27] Ancak kafein takviyesinin kuvvet performansına etkisi konusunda da çelişen sonuçlar mevcuttur. ...
... 28,29 Fakat Astorino ve ark., kafein takviyesinin alt ve üst vücut maksimal kuvvetini değiştirmeyeceğini savunurken; Beck ve ark., kafein takviyesi ile sa-dece üst vücut kuvvetinde gelişim tespit edildiğini ancak alt vücut kuvvetinde değişim gözlenmediğini vurgulamıştır. 23,30 Polito ve ark., dinamik kuvvette kafein takviyesinin etkisi olmadığını bildirmesine karşın Grgic ve ark., üst vücut dinamik kuvvetinin kafein takviyesi ile gelişebilecğini ancak alt vücutta bu etkinin olmayabileceğini vurgulamıştır. 26,29 Kafeininin performans geliştirici etkisi değikenlik göstermektedir ve alım zamanı, alım miktarı, nasıl alındığı, sporcunun günlük yaşantısındaki kullanım alışkanlığı gibi etkenlere bağlı olarak değişebilmektedir. ...
... Kafein, tüketiminin hemen ardından hızlı bir şekilde kana geçmesi ve 45-90 dk arasında kanda en yüksek oranda bulunması sebebiyle, yoğun olarak fiziksel yüklenmeden 60 dk öncesinde kafein takviyesi yapılmaktadır. 8,23,30,[32][33][34] Ancak Blanchard ve Sawers 5 mg.kg -1 kafein takviyesi sonrası plazma konsantrasyonunda hızlı bir yükselme görüldüğünü ve ortalama maksimum konsatrasyonun 9,9±1,1 µg/mL olduğunu bildirmiştir. 4 Quinlan ve ark. ...
Article
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Objective: This study aimed to find out effects of caffeine intake 30 min and 60 min before each exercise trial on maximal strength and vertical jump in resistance-trained men. Material and Methods: Forty-five resistance-trained male volunteered to participate to the study (age: 25.20±7.71 year, body weight: 78.53±9.31 kg, height: 177.46±6.54). Subjects were randomly divided in three groups: 1) Caffeine intake 30 min before exercises (CAF 30, n=15), 2) Caffeine intake 60 min before exercises (CAF 60, n=15) and placebo (PL, n=15). One repetition maximum bench press (1RM BP), one repetition maximum back squat (1RM BS), vertical jump, rating of perceived exertion (RPE), and level of received pain were measured with/without caffeine intake two times. Subjects ingested 5 mg/kg powder caffeine with 250 mL water 30 min or 60 min before exercises. PL group ingested 250 mL water with artificial sweetener. A two-way repeated measures ANOVA was used for data analyses. Results: There was no significant effect of caffeine on 1RM BP, 1RM BS and vertical jump in resistance- trained men (p>0.05). Caffeine intake did not change RPE and level of received pain after 1RM BP, 1RM BS exercises (p>0.05). No significant difference was found in 1RM BP, 1RM BS, vertical jump, RPE and the level of received pain between CAF 30 and CAF 60 (p>0.05). Conclusion: It can be said that caffeine intake may not affect 1RM BP, 1RM BS and vertical jump height, although linear increases in upper and lower body strength were observed with caffeine supplementation 30 min and 60 min before exercise. The numerical improvements seen in the CAF 30 group may indicate an early effect of caffeine supplementation.
... Nutritional ergogenic aids are foods or nutrients that can improve physical performance or accelerate recovery [1]. Among these ergogenic aids, Caffeine ingestion is highly prevalent among combat athletes [2,3] and this phenomenon has not been studied in judo either of Olympic combats considering real training situations. A full literature review did not demonstrate any research addressing caffeine ingestion and judo performance during the competitive season [4][5][6][7]. ...
... Recently, caffeine ingestion has presented a "sparing" effect of carbohydrates, thus improving running performance [11]. Furthermore, in judo, the flexibility of motor control depends on anticipation of subsequent opponent`s action as well as simultaneous and quick decision-making to spatiotemporal modifications, which specific-skills perhaps improve using caffeine, as demonstrated by preceding reports with combat sports [3,12,13]. Caffeine supplementation provided a significant difference in activities requiring maximum strength [3]; there was also a lower time-reaction in taekwondo athletes [13]. There is little knowledge about the effect of caffeine on judo performance [2,14,15], such studies focused on measuring the isolated effect in the Special Judo Fitness Test [2,14], demonstrating "unclear" evidence with confounding factors, as varied rapid weight loss processes without dietary control, using the same secondary data or a missing randomized sample and metabolic biomarkers. ...
... Furthermore, in judo, the flexibility of motor control depends on anticipation of subsequent opponent`s action as well as simultaneous and quick decision-making to spatiotemporal modifications, which specific-skills perhaps improve using caffeine, as demonstrated by preceding reports with combat sports [3,12,13]. Caffeine supplementation provided a significant difference in activities requiring maximum strength [3]; there was also a lower time-reaction in taekwondo athletes [13]. There is little knowledge about the effect of caffeine on judo performance [2,14,15], such studies focused on measuring the isolated effect in the Special Judo Fitness Test [2,14], demonstrating "unclear" evidence with confounding factors, as varied rapid weight loss processes without dietary control, using the same secondary data or a missing randomized sample and metabolic biomarkers. ...
Article
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Background Nutritional ergogenic aids are foods or nutrients that can improve physical performance. Among these foods with ergogenic properties, caffeine has shown that it can increase the fat catabolism, strength, and improve the cognition and time reaction of an athlete, therefore, it is hoped that it can improve the performance of judokas. This study through a double-blind crossover (supplement X placebo) protocol, investigated the effects caffeine supplementation (single capsule containing 5 mg/kg body mass intake 60 min before the session) on biochemical, anthropometrical, physical, subjective and hemodynamic variables measured before, during and after two typical judo trainingcxs sessions (120-min: 40-min of gymnastics; 40-min of specific technics and; 40-min of judo combat). Methods 8 high-level athletes (21.4 ± 2.0 years; 83.6 ± 15.2 kg; 1.8 ± 0.1 m; 17.9 ± 7.0 Fat%) were evaluated before and after each training for body mass, hydration, upper and lower limb power, performance in the special judo fitness test (SJFT), free fatty acids (FFA) in plasma, uric acid, glucose, lactate, heart rate, and pain. In addition, heart rate, FFA in plasma, uric acid, glucose, lactate, rating of perceived exertion and pain were assessed during the training. Results At 120 min, supplementation resulted in a higher concentration of plasma FFA (1.5 ± 0.5 vs. 1.0 ± 0.3 mmol/L; p = 0.047) and lactate (4.9 ± 1.8 vs. 3.0 ± 1.2 mmol/L; p = 0.047), and a lower concentration of uric acid (5.4 ± 0.9 vs. 7.0 ± 1.5 mg/dL; p = 0.04). Supplementation also resulted in performance maintenance (fatigue index) in the SJFT (Δ0.3 ± 2.0 vs Δ1.7 ± 2.5, for caffeine and placebo respectively, p = 0.046). No adverse effects were observed. Conclusion Based on the applied dose, intake time, and sample of this study, we can conclude that caffeine produces an ergogenic biochemical effect, and improves performance in judo athletes.
... This volume was based on the participants' training experience. It is also known that on average 80% of the 1RM applies to 2-5 repetition range [31]. Following an explanation of all procedures, risks and benefits associated with the study, each subject gave his written consent prior to participation. ...
... The average dosage of caffeine provided in this study was 3.4 mg·kg −1 . In other studies, where 1-RM bench press strength exercise was improved, the amount of caffeine in caffeine-containing supplement administrated was slightly lower (201 mg per dose = 2.4 mg·kg −1 ) [31]. However, the improvement in the study was around 2.1%, which is clearly lower than the strength improvement seen in the current study (7%), which could indicate a better chosen composition of additional active ingredients, which caused a better ergogenic synergistic effect of the of the MIPS investigated in this study. ...
... However, in many of these studies a number of pharmacologically active compounds were mixed together, so it is impossible to assess the effectiveness of each component separately. In this case, the effectiveness of each single ingredient remains unclear [31]. This is because multiple ingredients potentially interact and these interactions may potentiate or attenuate supplement effectiveness. ...
Article
Full-text available
Background: The purpose of this research was to investigate the acute effects of a pre-workout supplement on anaerobic performance in resistance-trained men. Methods: Twenty-three men underwent three randomized, double-blind testing sessions separated by a seven-day break. The participants performed three tests: isokinetic strength, three repetition maximum (3-RM) strength and Wingate. Statistical analysis was conducted in R environment. Linear mixed models were estimated via R package lme4. Results: Mean T@0.2 s was significantly greater in supplemented condition for right and left knee flexors (PL: 103.2 ± 37.6 Nm; supplemented condition: 131.8 ± 29.3 Nm (p = 0.001)), and PL: 103.7 ± 39.3; supplemented condition: 129.4 ± 28.4 (p = 0.001)). T@0.2 s for right and left knee extensors (PL: 202.6 ± 58.6 Nm; supplemented condition: 237.2 ± 54.7 Nm (p = 0.001); PL: 203.3 ± 63.2 Nm, supplemented condition: 229.8 ± 50.8 Nm (p = 0.002)). Significant difference was in mean anaerobic power between supplemented and PL condition for right and left knee flexors (p = 0.002, p = 0.005) and for right and left knee extensors (p = 0.001 and p = 0.002). TTP was significantly shorter in supplemented condition for both sides knee flexors (p = 0.002). There was a significant difference for mean power in the Wingate test (placebo: 8.5 ± 0.6 W/kg; supplemented condition: 8.7 ± 0.5 W/kg (p = 0.038)). Mean 3-RM was significantly greater in supplemented condition (p = 0.001). Conclusions: The supplement significantly improves upper and lower body strength and power output in resistance-trained men.
... Some studies have reported increases in various aspects of strength, power, and anaerobic performance during different exercise tasks, in subjects with different individual characteristics, and utilizing varying caffeine dosages [2,[8][9][10]17]. For example, Anselme et al. [2] reported significant increases in anerobic power during cycling following caffeine ingestion, while Beck et al. [8] found that a supplement containing caffeine increased bench press 1RM. ...
... Some studies have reported increases in various aspects of strength, power, and anaerobic performance during different exercise tasks, in subjects with different individual characteristics, and utilizing varying caffeine dosages [2,[8][9][10]17]. For example, Anselme et al. [2] reported significant increases in anerobic power during cycling following caffeine ingestion, while Beck et al. [8] found that a supplement containing caffeine increased bench press 1RM. Other studies, however, have reported conflicting results regarding caffeine and exercise performance [12,35,39,47]. ...
... Interestingly, Beck et al. [8] found that caffeine increased bench press 1RM compared to a placebo, but similar to our study, did not find increases in leg extension 1RM. These findings, as well as those of the present study, conflict with findings from a recent review and meta-analysis [50]. ...
Article
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Purpose The purpose of this study was to examine the effects of caffeine on peak torque (PT), rate of torque development (RTD), and muscle activation in college-age men. Methods Fifteen men (23.3 ± 2.2 years, 177.6 ± 8.7 cm, 90.3 ± 19.1 kg) volunteered to participate in this study. During each of two test sessions, maximal leg extension PT and RTD were determined and electromyographic (EMG) and mechanomyographic (MMG) signals were collected to examine electrical and mechanical aspects of muscle activation, respectively. Participants also performed the Wingate Anaerobic Test (WAnT) for the determination of peak power (PP), mean power (MP), and fatigue percentage (FP). For the first test session, participants were randomly assigned to ingest either a caffeinated drink (6 mg/kg) or a placebo 1 h prior to testing. The second test session was identical to the first, but the drink not previously administered was ingested prior to testing. Results The results indicated there were no significant effects of caffeine on PT, PP, MP, FP, or EMG and MMG measures. However, RTD was positively affected by caffeine (856.4 ± 246.4 Nm/s) compared to the placebo condition (710.9 ± 267.9 Nm/s). Conclusions These results suggest that caffeine can be an effective aid for sport activities requiring maximal rates of force or torque development during very short time periods.
... Caffeine (1, 3, 7-trimethylxanthine) is a methylxanthine that exerts a stimulatory effect through stimulation of the central nervous system (CNS). A plethora of research exists reporting both ergogenic effects and no effect of caffeine on muscular endurance [10][11][12][13][14][15][16][17][18][19][20][21], strength [12][13][14][15][20][21][22][23][24][25][26], and power [15,[27][28][29][30]. Given the similarities between TeaCrine® and caffeine, and the absence of resistance exercise data with TeaCrine®, the purpose of this study was to examine the effects of 300 mg TeaCrine® (TEA300), 150 mg Caffeine + 150 mg TeaCrine® (COMBO), and 300 mg Caffeine (CAFF300) compared to placebo (PLA) on muscular strength (1RM), endurance (repetitions to failure [RTF] at 70% 1RM), and power in the bench press and squat exercises, wherein a 300 mg dose of caffeine was used to match the 150/150 mg Caffeine/Tea-Crine® blend. ...
... Bench press 1RM was 2.2% higher in the CAFF300 group compared to PLA (p = 0.19, η p 2 = 0.007) and, while not significant, was descriptively similar to previous research that reported significant increases in performance with caffeine ingestion [22,26]. Beck et al. [26] reported a 2.1% (+ 2.1 kg) increase in bench press 1RM following ingestion of a 201 mg caffeine containing supplement (approximately 2.4 mg/kg) compared to placebo. ...
... Bench press 1RM was 2.2% higher in the CAFF300 group compared to PLA (p = 0.19, η p 2 = 0.007) and, while not significant, was descriptively similar to previous research that reported significant increases in performance with caffeine ingestion [22,26]. Beck et al. [26] reported a 2.1% (+ 2.1 kg) increase in bench press 1RM following ingestion of a 201 mg caffeine containing supplement (approximately 2.4 mg/kg) compared to placebo. However, there were differences in the sample size (n = 37 vs n = 12). ...
Article
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Background: TeaCrine® is the synthetic version to naturally occurring theacrine (1, 3, 7, 9-tetramethyluric acid) found in the leaves of Camellia kucha tea plants. A few studies have examined the effects of TeaCrine® on cognitive perception, but no research exists examining its effects on resistance exercise performance. The purpose of this study was to determine the efficacy of TeaCrine®, a caffeine-like compound, on maximal muscular strength, endurance, and power performance in resistance-trained men. Methods: Twelve resistance-trained men participated in a randomized, double-blind, cross-over designed study. Each participant performed one-repetition maximum (1RM) bench press, 1RM squat, bench press repetitions to failure (RTF) at 70% 1RM, squat RTF at 70% 1RM, and 2-km rowing time trial 90 min after consumption of: (1) Caffeine 300 mg (CAFF300); (2) TeaCrine® 300 mg (TEA300); (3) TeaCrine® + Caffeine (COMBO; 150 mg/150 mg); (4) Placebo 300 mg (PLA). Power and velocity were measured using a TENDO Power Analyzer. Visual analogue scales for energy, focus, motivation to exercise, and fatigue were administered at baseline and 90 min post-treatment ingestion (pre-workout). Rating of perceived exertion was assessed after bench press RTF and squat RTF. Results: There were no differences between groups for 1RM, RTF, and power in the bench press and squat exercises. Only CAFF300 resulted in significant increases in perceived energy and motivation to exercise vs. TEA300 and PLA (Energy: + 9.8%, 95% confidence interval [3.3-16.4%], p < 0.01; + 15.3%, 95% CI [2.2-28.5%], p < 0.02; Motivation to exercise: + 8.9%, 95% CI [0.2-17.6%], p = 0.04, + 14.8%, 95% CI [4.7-24.8%], p < 0.01, respectively) and increased focus (+ 9.6%, 95% CI [2.1-17.1%], p = 0.01) vs. TEA300, but there were no significant differences between CAFF300 and COMBO (Energy + 3.9% [- 6.9-14.7%], Focus + 2.5% [- 6.3-11.3%], Motivation to exercise + 0.5% [- 11.6-12.6%]; p > 0.05). Conclusion: Neither TEA300, CAFF300, COMBO, or PLA (when consumed 90 min pre-exercise) improved muscular strength, power, or endurance performance in resistance-trained men. Only CAFF300 improved measures of focus, energy, and motivation to exercise.
... Caffeine is one of the most extensively studied and widely used ergogenic aid capable of improving many aspects of sport performance and cognitive abilities [1][2][3][4][5][6][7][8][9][10][11][12]. Some of the acute effects of caffeine supplementation are increases anaerobic power output and performance, increased muscular strength, endurance, and power, improvements to aerobic endurance, reduced fatigue, decreased RPE and pain, increased voluntary workload, and increased alertness [1][2][3][4][5][6][7][8]. ...
... Caffeine is one of the most extensively studied and widely used ergogenic aid capable of improving many aspects of sport performance and cognitive abilities [1][2][3][4][5][6][7][8][9][10][11][12]. Some of the acute effects of caffeine supplementation are increases anaerobic power output and performance, increased muscular strength, endurance, and power, improvements to aerobic endurance, reduced fatigue, decreased RPE and pain, increased voluntary workload, and increased alertness [1][2][3][4][5][6][7][8]. Chronic caffeine consumption has also been shown to have a positive effect on long term memory, locomotor improvements, and overall mood state [9][10][11]. ...
... Furthermore, caffeine has been shown to increase calcium release from the sarcoplasmic reticulum of muscle fibers, which could result in increased actinmyosin binding and therefore increased force production [12]. Some of the acute physical effects of caffeine supplementation are increases anaerobic power output and performance, increased muscular strength, endurance and power, improvements to aerobic endurance, and reduced fatigue [1,[3][4][5][6]8]. Additionally, acute caffeine consumption also enhances cognitive function during physical tasks as demonstrated through a reduction in self-reported rate of perceived exertion (RPE) and pain perception, increasing voluntary choice of work load, and increasing alertness [2,7,9]. ...
... Endurance (Watt et al. 2003) and resistance exercise studies indicate the use of caffeine-based supplements improve acute exercise time to exhaustion, local muscular endurance (Beck et al. 2006;Duncan and Oxford 2012), muscular power (Gonzalez et al. 2011), mood , and indices of muscle damage (Hurley et al. 2013). Similarly, pre-workout supplementation alters endocrine responses following RE (Hoffman et al. 2008). ...
... The effect of caffeine supplementation and caffeinecontaining pre-workout supplements on MAPK activation and β 2 -AR signaling following acute resistance exercise has not been studied. MAPK are influenced by the volume and load of the resistance exercise stimulus (Holm et al 2010;Hulmi et al. 2012) and caffeine supplementation increases muscular endurance (Beck et al. 2006;Duncan and Oxford 2012). Since caffeine increases local muscular endurance during resistance exercise, this could result in potentiated MAPK phosphorylation responses. ...
Article
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AimThe acute myocellular responses of caffeine supplementation during resistance exercise (RE) have not been investigated. β2-Adrenergic receptors (β2AR) may be a target of the stimulatory effects of caffeine and stimulate bioenergetic pathways including protein kinase A (PKA), and mitogen-activated protein kinases (MAPK).PurposeElucidate the effects of pre-workout supplementation on signaling responses to an acute RE bout.Methods In a randomized, counter-balanced, double-blind, placebo-controlled, within-subject crossover study, ten resistance-trained males (mean ± SD; age = 22 ± 2.4 years, height = 175 ± 7 cm, body mass = 84.1 ± 11.8 kg) consumed a caffeine containing multi-ingredient pre-workout supplement (SUPP) or color and flavor matched placebo (PL) 60 min prior to an acute RE bout of barbell back squats. Pre- and post-exercise muscle biopsies were analyzed for the phosphorylation (p-) of β2AR, PKA, and MAPK (ERK, JNK, p38). Epinephrine was determined prior to supplementation (baseline; BL), after supplementation but prior to RE (PRE), and immediately after RE (POST).ResultsEpinephrine increased at PRE in SUPP (mean ± SE: 323 ± 34 vs 457 ± 68 pmol/l; p = 0.028), and was greatest at POST in the SUPP condition compared to PL (5140 ± 852 vs 2862 ± 498 pmol/l; p = 0.006). p-β2AR and p-MAPK increased post-exercise (p < 0.05) with no differences between conditions (p > 0.05). Pearson correlations indicated there was a relationship between epinephrine and p-β2AR in PL (r = − 0.810; p = 0.008), and p-β2AR and ERK in SUPP (r = 0.941; p < 0.001).Conclusion Consumption of a caffeine containing pre-workout supplement improves performance, possibly through increases in pre-exercise catecholamines. However, the acute myocellular signaling responses were largely similar post-exercise.
... With currently available scientific studies, it is difficult to confirm the positive effect of CAF on maximal strength during the BP exercise. For instance, several studies found no effect of CAF on the 1RM test during the BP exercise [4,28,64,69], but contrary different investigations showed the positive effect of CAF supplementation on maximal strength [2,7,16,23,46]. The inconsistencies in results of the studies can be explained mainly by differences in characteristics of participants including a) training experience, b) strength level c) relation of used CAF dose to the level of habitual CAF intake. It is worth noticing, that studies, which involved participants who reported lower experience in resistance training [2,23] showed a positive effect of CAF supplementation. ...
... However, the results of the studies utilizing the BP exercise showed conflicting results. Most of the studies (Table 3) did not show the positive effect of CAF on strength-endurance during the BP exercise [3,4,7,23,25,28,63,69]. On the contrary, in two investigations conducted by Diaz-Lara et al. [16] and Duncan and Oxford [17] CAF improved the number of repetitions performed to muscular failure. ...
Article
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Introduction. Caffeine (CAF) is widely consumed psychoactive substance and one of the most used supplements. Due to the fact that strength and power training has become an essential component of conditioning programs in most of the competitive sports, the need for more specific analysis of CAF in terms of resistance training has been established. Furthermore, most of the research focused on the acute effects of CAF supplementation on muscle performance utilized the bench press (BP) exercise. Taking into consideration the popularity of the BP exercise, the main purpose of this review is to evaluate the current state of knowledge on the impact of CAF supplementation on the BP performance and to point out practical guidelines. Material and Methods. PubMed, Medline and GoogleScholar databases were searched from 2006 to 2020 for studies evaluating the effects of CAF on: (1) maximal muscle strength; (2) power output; and (3) strength-endurance performance as assessed in the BP exercise. Twenty-three articles met the inclusion criteria and were consequently included in the review. Results. In general, CAF in doses of 3 to 6 mg/kg has been found to be a safe ergogenic aid during the BP exercise in terms of improving maximal strength and power output, however the impact of CAF intake on strength-endurance is less clear. Additionally, doses of 9 mg/kg and 11 mg/kg might be ergogenic in the improvement of maximal strength and power output, however higher frequency of side effects observed has to be considered in supplementation strategy. Conclusions. The performed review showed that acute CAF intake can be an effective strategy to improve resistance training outcomes for maximal strength and power output tests during the BP exercise. However, extrapolation of these guidelines to long--term benefits of CAF influence on the BP exercise remains limited due to lack of evidence in this area. © 2021, University School of Physical Education. All rights reserved.
... In the literature, it was found twelve studies that investigated the effect of caffeine supplementation on strength assessed by 1RM. Five of them found an increase of maximum strength [4][5][6][7][8] , whereas seven others observed no difference on strength followed caffeine ingestion [9][10][11][12][13][14] . Besides some differences among the studies, some limitations regarding 1RM, such as familiarization, ingestion of substances other than only caffeine, and comparisons with control or placebo groups only. ...
... Another main point of our study is the absence of any ergogenic substance other than caffeine. It was observed in other studies the ingestion of another type of ergogenic that might have influenced on the results 7,8,11,14 . Thereby, it is debatable to affirm that the increase in strength was originated by the caffeine only. ...
Article
This article analyzed whether the caffeine supplementation improves bench press one repetition maximum test (1RM) performance. It is a pre-experimental, single-moment, cross-over, counterbalanced, double-blind study. Twenty men (age 23 ± 3 years; body mass 77.72 ± 6.68 kg; height 1.77 ± 0.06 cm; body mass index 24.77 ± 1.57), experienced in resistance training (5.8 ± 2.93 years), performed four visits to the laboratory; the first visit was composed by baseline assessments and 1RM familiarization. All subjects underwent 1RM in three following conditions: caffeine supplementation (420 mg), placebo intake (420 mg cornstarch), given 45 minutes prior to the start of the test, and control. According to data analyses, ANOVA One Way was performed and the level of significance was set at p≤0.05. It was verified there were no significant differences in the maximum strength between the conditions (F(2,4) = 0.011; p = 0.99) and the average loads obtained in each of them were 96.6 ± 19.55 kg for caffeine supplementation, 96.9 ± 18.46 kg for placebo intake, and 96.00 ± 19.04 kg for control. Caffeine intake has no effect on maximal strength performance for a scapular girdle and upper limbs in trained men. Thus, it is unnecessary to recommend deprivation of caffeine use prior to the application of the 1RM test.
... Dado que se han utilizado dosis de 2.4 mg/kg, se sugiere que estas podrían ser insuficientes para observar un efecto ergogénico sobre el rendimiento anaeróbico. Beck et al. (2006), indican que dosis de cafeína de 5 a 6 mg/kg podrían ser necesarias para mejorar las capacidades anaeróbicas. ...
... Las personas que no consumen cafeína regularmente pueden ser más propensas a experimentar efectos ergogénicos, en comparación con las personas que consumen cafeína regularmente. Esto probablemente se debe a un proceso de adaptación/asimilación en el que muchos de los efectos de una dosis aguda de cafeína se atenúan con su consumo crónico (Beck et al., 2006;Forbes et al., 2007;Maridakis, O'Connor, Dudley, y McCully, 2007). ...
Article
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Arias-Oviedo, G.M.; Castillo-Hernández, I. y Jiménez-Díaz, J. (2019). Efecto agudo de las bebidas energéticas en el rendimiento anaeróbico: Un metaanálisis. Pensar en Movimiento: Revista de Ciencias del Ejercicio y la Salud, 17(2), 1-23. El consumo de bebidas energéticas (BE) ha ido incrementando tanto en estudiantes y personas activas como en deportistas, esto por posible efecto ergogénico. Dichas bebidas contienen, además de calorías, cafeína en combinación con otros ingredientes como taurina, carnitina y vitaminas del complejo B. El objetivo del estudio fue evaluar el efecto agudo de la ingesta de BE en el rendimiento físico anaeróbico, por medio de la técnica de metaanálisis. La metodología consistió en realizar una búsqueda en cinco bases de datos: PubMed, SPORTDiscus, Springer Link, ProQuest y Science Direct. Se seleccionaron los estudios que cumplieron con los criterios de elegibilidad: experimentales, en los que se midiera el rendimiento anaeróbico y donde se suministrara una BE, realizados en seres humanos, que presentaran la estadística descriptiva y estuviesen publicados en idioma español o inglés. Como resultados se incluyeron 15 estudios que generaron 37 tamaños de efecto (TE) y un total de 253 sujetos (hombres y mujeres; 21,7±3,7 años). Bajo el modelo de efectos aleatorios y un diseño entre grupos se obtuvo un TE global de 0.123 (p = 0.009; IC95% = 0.01 a 0.23; Q = 19.5; p= 0.98; I2 = 0.00%). No se encontró ninguna relación o diferencia en las variables moderadoras. En conclusión, el TE global indica que hay diferencia significativa entre consumir BE o placebo para pruebas anaeróbicas específicas de saltos.
... During the first session, baseline measurements (height, body mass, and VȮ 2 max) were taken, and subjects were familiarized with the WAnT protocol (7,26). The WAnT assessment was chosen in this study because it is one of the most popular anaerobic cycling tests and is known for being a reliable and valid method of measuring anaerobic abilities (7). ...
... During the first session, baseline measurements (height, body mass, and VȮ 2 max) were taken, and subjects were familiarized with the WAnT protocol (7,26). The WAnT assessment was chosen in this study because it is one of the most popular anaerobic cycling tests and is known for being a reliable and valid method of measuring anaerobic abilities (7). ...
Preprint
Anderson, DE, German, RE, Harrison, ME, Bourassa, KN, and Taylor, CE. Real and perceived effects of caffeine on sprint cycling in experienced cyclists. J Strength Cond Res XX(X): 000-000, 2020-Caffeine ingestion before an exercise bout may provide ergogenic effects on anaerobic performance, particularly in trained athletes. However, the degree of influence of caffeine may be coupled with the placebo effect. A double-blind, placebo-controlled, randomized design was used to determine the real and perceived effects of caffeine on anaerobic performance. Ten competitively trained cyclists (9 men and 1 woman) completed 3 trials of the Wingate Anaerobic Test (WAnT). Subjects were given coffee that they believed contained a high caffeine dose, a low caffeine dose, or a placebo 45 minutes before WAnT. Subjects were actually given 2 placebos (decaffeinated coffee) and one dose of caffeine (280 mg). Level of significance was p # 0.05. No significant differences were found between trials for blood lactate concentration and heart rate. Seven of the subjects (70%) correctly identified the caffeine trial as the high caffeine trial. Time to peak power was significantly shorter for the trial in which subjects incorrectly guessed they had consumed caffeine when given the placebo compared with placebo trial (1.6 6 0.1 vs. 2.3 6 0.2 seconds). Power drop was significantly higher for the trial in which subjects incorrectly guessed they had consumed caffeine when given the placebo compared with placebo trial (524 6 37 vs. 433 6 35 W). There seems to be a placebo effect of caffeine on anaerobic performance. Improved performance may result from psychological advantages rather than physical advantages. Coaches may find it beneficial to use a placebo to improve anaerobic performance, especially if concerned about the side effects or cost of caffeine.
... During the first session, baseline measurements (height, body mass, and VȮ 2 max) were taken, and subjects were familiarized with the WAnT protocol (7,26). The WAnT assessment was chosen in this study because it is one of the most popular anaerobic cycling tests and is known for being a reliable and valid method of measuring anaerobic abilities (7). ...
... During the first session, baseline measurements (height, body mass, and VȮ 2 max) were taken, and subjects were familiarized with the WAnT protocol (7,26). The WAnT assessment was chosen in this study because it is one of the most popular anaerobic cycling tests and is known for being a reliable and valid method of measuring anaerobic abilities (7). ...
Article
Anderson, DE, German, RE, Harrison, ME, Bourassa, KN, and Taylor, CE. Real and perceived effects of caffeine on sprint cycling in experienced cyclists. J Strength Cond Res XX(X): 000-000, 2020-Caffeine ingestion before an exercise bout may provide ergogenic effects on anaerobic performance, particularly in trained athletes. However, the degree of influence of caffeine may be coupled with the placebo effect. A double-blind, placebo-controlled, randomized design was used to determine the real and perceived effects of caffeine on anaerobic performance. Ten competitively trained cyclists (9 men and 1 woman) completed 3 trials of the Wingate Anaerobic Test (WAnT). Subjects were given coffee that they believed contained a high caffeine dose, a low caffeine dose, or a placebo 45 minutes before WAnT. Subjects were actually given 2 placebos (decaffeinated coffee) and one dose of caffeine (280 mg). Level of significance was p ≤ 0.05. No significant differences were found between trials for blood lactate concentration and heart rate. Seven of the subjects (70%) correctly identified the caffeine trial as the high caffeine trial. Time to peak power was significantly shorter for the trial in which subjects incorrectly guessed they had consumed caffeine when given the placebo compared with placebo trial (1.6 ± 0.1 vs. 2.3 ± 0.2 seconds). Power drop was significantly higher for the trial in which subjects incorrectly guessed they had consumed caffeine when given the placebo compared with placebo trial (524 ± 37 vs. 433 ± 35 W). There seems to be a placebo effect of caffeine on anaerobic performance. Improved performance may result from psychological advantages rather than physical advantages. Coaches may find it beneficial to use a placebo to improve anaerobic performance, especially if concerned about the side effects or cost of caffeine.
... Although studies have confirmed the ergogenic effects of caffeine in many aspects, much controversy remains about the effects of acute CAF intake on maximal strength (1-repetition maximum (1RM)) and local muscle endurance. Several investigations have found that the acute intake of 3-6 mg/kg/b.m. of CAF produces an increase in 1RM test performance [3,[12][13][14], and in the total number of repetitions performed (T-REP) [12,13,15]. However, other investigations have found that the same dosage did not produce such effects [2,3,5,15,16], suggesting that other factors such as the type of testing, the muscle mass involved, and the athlete's experience in strength training might affect the ergogenic effect of caffeine on muscle performance. ...
... Previous studies have shown a variety of effects when different doses of CAF were administered to athletes performing testing to assess maximum strength and muscle endurance. Some of them indicated a significant increase in 1RM and T-REP performance [12,13], while others did not confirm such benefits [2,14]. Perhaps differences in the results of previous studies may be attributed to different doses of CAF consumed by study participants, in addition to the use of participants with an uneven habituation to caffeine. ...
Article
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Background: The main goal of this study was to assess the acute effects of the intake of 9 and 11 mg/kg/ body mass (b.m.) of caffeine (CAF) on maximal strength and muscle endurance in athletes habituated to caffeine. Methods: The study included 16 healthy strength-trained male athletes (age = 24.2 ± 4.2 years, body mass = 79.5 ± 8.5 kg, body mass index (BMI) = 24.5 ± 1.9, bench press 1RM = 118.3 ± 14.5 kg). All participants were habitual caffeine consumers (4.9 ± 1.1 mg/kg/b.m., 411 ± 136 mg of caffeine per day). This study had a randomized, crossover, double-blind design, where each participant performed three experimental sessions after ingesting either a placebo (PLAC) or 9 mg/kg/b.m. (CAF-9) and 11 mg/kg/b.m. (CAF-11) of caffeine. In each experimental session, participants underwent a 1RM strength test and a muscle endurance test in the bench press exercise at 50% 1RM while power output and bar velocity were measured in each test. Results: A one-way repeated measures ANOVA revealed a significant difference between PLAC, CAF-9, and CAF-11 groups in peak velocity (PV) (p = 0.04). Post-hoc tests showed a significant decrease for PV (p = 0.04) in the CAF-11 compared to the PLAC group. No other changes were found in the 1RM or muscle endurance tests with the ingestion of caffeine. Conclusion: The results of the present study indicate that high acute doses of CAF (9 and 11 mg/kg/b.m.) did not improve muscle strength nor muscle endurance in athletes habituated to this substance.
... Dado que se han utilizado dosis de 2.4 mg/kg, se sugiere que estas podrían ser insuficientes para observar un efecto ergogénico sobre el rendimiento anaeróbico. Beck et al. (2006), indican que dosis de cafeína de 5 a 6 mg/kg podrían ser necesarias para mejorar las capacidades anaeróbicas. ...
... Las personas que no consumen cafeína regularmente pueden ser más propensas a experimentar efectos ergogénicos, en comparación con las personas que consumen cafeína regularmente. Esto probablemente se debe a un proceso de adaptación/asimilación en el que muchos de los efectos de una dosis aguda de cafeína se atenúan con su consumo crónico (Beck et al., 2006;Forbes et al., 2007;Maridakis, O'Connor, Dudley, y McCully, 2007). ...
Article
El consumo de bebidas energéticas (BE) ha ido incrementando tanto en estudiantes y personas activas como en deportistas, esto por posible efecto ergogénico. Dichas bebidas contienen, además de calorías, cafeína en combinación con otros ingredientes como taurina, carnitina y vitaminas del complejo B. El objetivo del estudio fue evaluar el efecto agudo de la ingesta de BE en el rendimiento físico anaeróbico, por medio de la técnica de metaanálisis. La metodología consistió en realizar una búsqueda en cinco bases de datos: PubMed, SPORTDiscus, Springer Link, ProQuest y Science Direct. Se seleccionaron los estudios que cumplieron con los criterios de elegibilidad: experimentales, en los que se midiera el rendimiento anaeróbico y donde se suministrara una BE, realizados en seres humanos, que presentaran la estadística descriptiva y estuviesen publicados en idioma español o inglés. Como resultados se incluyeron 15 estudios que generaron 37 tamaños de efecto (TE) y un total de 253 sujetos (hombres y mujeres; 21,7±3,7 años). Bajo el modelo de efectos aleatorios y un diseño entre grupos se obtuvo un TE global de 0.123 (p = 0.009; IC95% = 0.01 a 0.23; Q = 19.5; p= 0.98; I2 = 0.00%). No se encontró ninguna relación o diferencia en las variables moderadoras. En conclusión, el TE global indica que hay diferencia significativa entre consumir BE o placebo para pruebas anaeróbicas específicas de saltos.
... Kafeinin dayanıklılık performansına pozitif etkisini işaret eden birçok araştırma [14,[17][18][19] bulunmasına karşın kısa süreli yüksek yoğunluklu egzersize etkisi hakkındaki bulgular çelişkilidir. Back ve ark [20] kafein içerikli takviyelerin direnç antrenmanlı bireylerde üst vücut kuvvetinde artışa neden olurken alt vücut kuvveti ve anaerobik kapasiteye etkisinin olmadığını bildirmiştir. Diğer bir araştırmada ise sedanter bireylere yapılan kafein takviyesi sonrasında üst vücut kuvvetinde değişim gözlenmediği rapor edilmiştir [21]. ...
... Diğer bir araştırmada ise sedanter bireylere yapılan kafein takviyesi sonrasında üst vücut kuvvetinde değişim gözlenmediği rapor edilmiştir [21]. Astorino ve ark [22] [16,20,22,28]. Bu uygulamalar, kafein takviyesinden 1 saat sonra kandaki kafein seviyesinin en yüksek seviyede görülmesinden kaynaklanmaktadır [3,7]. ...
... En modalidades de resistencia aeróbica, en las que la suplementación con cafeína ha demostrado presentar un efecto ergogénico 14 , se ha sugerido que la dosis mínima eficaz es de 3 mg·kg -alanina 1 29 a 3.2 mg·kg -alanina 1 30 de cafeína, encontrándose un efecto meseta hasta dosis de 9 mg·kg -alanina 1 31 . En este sentido, distintas investigaciones que han valorado dosis inferiores a dichas cantidades, tales como 1 mg·kg -alanina 1 32 , 2 mg·kg -alanina 1 33,34 o 201 mg (2.4 mg·kg -alanina 1 , aproximadamente) 35 de cafeína, en distintos ejercicios como pudiera ser la extensión de rodillas, sentadilla o press de banca no han demostrado tener ningún efecto ergogénico. ...
... En un estudio en el que se suplementó a un grupo de hombres con un alto nivel de entrenamiento en fuerza se comprobó que una suplementación con 2.4 mg·kg -alanina 1 de cafeína, aunque no indujo mejoras en 1 RM en extensión de piernas, si provocó mejoras en el ejercicio de press de banca 35 . En el mismo ejercicio, otros estudios han comprobado efectos positivos ante dosis de 3 mg·kg -alanina 1 , en jóvenes entrenados en fuerza 36 , y de 6 mg·kg -alanina 1 , en mujeres entrenadas en fuerza 31 . ...
Article
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The use of certain supplements can enhance athletic performance, although the effectiveness of these is dependent on the demands imposed by the effort. Caffeine supplementation has proven effective, especially in patterns of cardiorespiratory endurance, however, they are less than the number of studies that have evaluated the effectiveness of this supplement on performance in muscle function. In order to assess the effect of caffeine supplementation on the production of muscle strength, it has made a search intervention bases Dialnet, Medline, PubMed and Web of Science data, in a period between 205 and 2015 and published in English, Spanish or Portuguese, which had evaluated the effects of this supplementation on strength performance. The results of the various investigations have shown that caffeine supplementation improves performance in the application of force and power with over 50% of one repetition maximum (1RM) loads as well as the number of repetitions with submaximal loads, especially, as the number of sets performed. © 2019 Centro Andaluz de Medicina del Deporte. All rights reserved.
... Among them are caffeine, creatine monohydrate, sodium bicarbonate and beta alanine [13]. Although studies have confirmed the ergogenic effects of caffeine (CAF) in many aspects, much controversy remains about its effects on the power generated by the upper limbs [14,15]. The most frequently consumed dose of caffeine during research with athletes ranges from 2 to 9 mg/kg body mass, ingested in the form of pills or capsules 30 to 90 min before exercise. ...
... Goldstein et al. [18] demonstrated a significant effect of CAF supplementation on strength in a group of women. On the contrary, Astorino et al. [37], Beck et al. [15] did not find such an effect in a group of experienced strength athletes. One should emphasize that previous research on CAF supplementation and the level of strength and power, as well as the number of performed repetitions considered resistance exercises performed at volitional or maximal velocity (V) of the entire movement, without a precise control of movement tempo during the concentric (CON) and eccentric (ECC) phases. ...
Article
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Background The ability to generate high levels of power is one of the key factors determining success in many sport disciplines. Although there are studies confirming ergogenic effects of caffeine (CAF) on different physical and mental abilities, much controversy remains about its influence on power. The main goal of this study was to assess the effects of caffeine supplementation on time under tension (TUT) and the number of performed repetitions (REP). The second objective was to determine the effects of CAF supplementation on power (P) and movement velocity (V) during the bench press movement. Additionally the authors evaluated whether CAF has a significant effect on velocity of the bar in the eccentric (ECC) phase (VEMEAN) of the bench press movement. Methods The study included 20 men (20–31 yrs., 87.3 ± 7.7 kg) with at least 2 years of experience in resistance training. The study participants were divided randomly into two groups: the supplemented group ingested caffeine before exercise (GCAF), while the control group was given a placebo (GCON). The exercise protocol consisted of performing the bench press movement with a load equal to 70%1RM with maximal possible velocity (X/0/X/0). The experimental sets were performed to momentary muscular failure. Results The repeated measures ANOVA between the GCAF and GCON groups revealed statistically significant differences in 2 variables. Post-hoc tests demonstrated statistically significant differences in TUT when comparing the group supplemented with caffeine (13.689 s GCAF) to the one ingesting a placebo (15.332 s GCON) at p = 0.002. Significant differences were also observed in mean velocity during the eccentric phase of movement (0.690 m/s in the GCAF to 0.609 in GCON with p = 0.002). There were no significant differences in generated power and velocity in the CON phase of the movement between the GCAF and GCON. Conclusions The main finding of the study is that CAF ingestion increases movement velocity of the bar in the eccentric phase of the movement, what results in shortening of the time under tension (TUT) needed for performing a specific number of repetitions, without decreasing power and velocity in the CON phase of the movement.
... Proposed mechanisms that may explain the ergogenic effects of caffeine is improved neuromuscular function, increased endorphin release, improved vigilance and alertness, and reduced perception of exertion during exercise [28]. There are studies indicating its positive effects on endurance performance [8,22], muscular endurance [14,35], muscular strength and power [3,12,19], and sprint performance [7,26]. ...
Article
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Study aim : The purpose of this study was to evaluate the acute effect of different four caffeine mouth rinse intervention (caffeinated coffee, decaffeinated coffee, placebo, control) on attention and hand-eye coordination. Material and methods : Sixty-five healthy, recreationally active female (n = 41) (age 22.89 ± 3.94 years; body mass index 20.87 ± 2.63 kg/m ² ) and male (n = 24) (age 29.91 ± 12.06 years; body mass index 22.56 ± 2.21 kg/m ² ) volunteered to participate in this randomized, single-blind, placebo-controlled, crossover study. The Stroop Color-Word Test (SCWT) and Mirror-Tracing Test (MTT) was used. Participants first completed a SCWT or MTT, then rinsed and expectorated 25 ml of caffeinated coffee (containing 0.13% caffeine) or decaffeinated coffee or placebo (water) or control that did not rinse for 10 s, followed by SCWT or MTT again. Data were analyzed using a 4 (mouth rinse interventions) × 2 (pre-test and post-test) repeated measures ANOVA. Results : SCWT time, MTT draw time and MTT number of error measures were not significantly different between four mouth rinse interventions (p > 0.05). Conclusions : Caffeinated coffee or decaffeinated coffee mouth rinse for 10 s provided immediately prior to SCWT or MTT did not affect attention and hand-eye coordination.
... In addition, the subjects were deprived of ingesting caffeine or similar substances due to their ergogenic effect. 35 The warm-up was identical in each session and consisted of 5 min of stationary bike (50 W with a cadence of 65 revolutions per minute), followed by performing 10 bench press repetitions with progressively increasing velocity using the initial load (5 kg). As previously mentioned, each subject performed series along the entire load spectrum (from 5 kg of the bar to 1RM), performing the bench press exercise. ...
Article
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This study aimed to evaluate the reliability and the level of agreement of the ADR encoder to measure the mean propulsive velocity (MPV) of the bar in the bench press (BP) exercise on the Smith machine. Eleven males (21.6 ± 1.5 years; body mass 76.05 ± 9.73 kg) performed the protocol with isometric phase prior to concentric muscle action (PP) and the protocol in the absence of isometric phase (N-PP) for BP exercise on Smith machine. ADR encoder reported reliability values with almost perfect correlations in all training zones and protocols (PP: ICC = 0.940–0.999, r = 0.899–0.997, CV = 1.56%–4.05%, SEM = 0.0022–0.0153,and MDC = 0.006–0.031 m/s; N-PP: ICC = 0.963–0.999, r = 0.946–0.998, CV = 0.70%–3.01%, SEM = 0.0012–0.0099, and MDC = 0.003–0.027 m/s). Although the levels of agreement were high in both protocols (PP: SEM = 0.0024–0.0204 m/s, MDC = 0.007–0.057 m/s; N-PP: SEM = 0.0034–0.0288 m/s, MDC = 0.009–0.080 m/s), ADR encoder considerably underestimated the MPV values in both protocols (PP: t = −2.239 to −9.486, p < 0.001–0.01; N-PP: t = −6.901 to −17.871, p < 0.001) with respect to the gold standard (T-Force). In conclusion, ADR encoder offers high reliability for the measurement of MPV in bench press exercise performed on Smith machine regardless of their execution mode, in the entire range of intensities. However, this device is not interchangeable with T-Force since it considerably underestimates the MPV values, especially at low loads (0%–40%). Furthermore, the use of too wide load ranges suggests that the data be interpreted with caution, pending further research to corroborate the findings presented.
... Mechanisms of paraxanthine's potential ergogenic effects include (A) an increase in plasma free fatty acids, a source of fuel that the body can utilize to produce energy [4], (B) a reduction of plasma K + concentrations which may attenuate the onset of skeletal muscle fatigue, and (C) an increase in calcium ions in the skeletal muscle, which is involved in muscle contractions [18]. While sports nutrition studies of paraxanthine are lacking at this time, previous work has illustrated the ability of acute caffeine supplementation to increase strength [2,19] while ergogenic outcomes related to muscular endurance are somewhat mixed [20][21][22][23]. Paraxanthine is the primary metabolite of caffeine metabolism and has been linked to caffeine's beneficial effects on athletic performance. ...
Article
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Paraxanthine is a natural dietary ingredient and the main metabolite of caffeine in humans. Compared to caffeine, paraxanthine exhibits lower toxicity, lesser anxiogenic properties, stronger locomotor activating effects, greater wake promoting properties, and stronger dopaminergic effects. The purpose of this study was to evaluate the potential beneficial effects of paraxanthine supplementation on muscle mass, strength, and endurance performance in comparison to the control and other ingredients commonly used by athletes: L-theanine, alpha-GPC, and taurine. Male Swiss Albino mice from five groups (n = 8 per group) were orally administered paraxanthine (20.5 mg/kg/day, human equivalence dose (HED) 100 mg), L-theanine (10.28 mg/kg/day, HED 50 mg), alpha-GPC (41.09 mg/kg/day, HED 200 mg), taurine (102.75 mg/kg/day, HED 500 mg), or control (carboxy methyl cellulose) for 4 weeks. Exercise performance was evaluated using forelimb grip strength and treadmill endurance exercise. All animals were subject to treadmill training for 60 min 5 days per week. Blood draws were utilized to analyze lipid profile, liver health, renal function, and nitric oxide levels. Paraxanthine significantly increased forelimb grip strength by 17% (p < 0.001), treadmill exercise performance by 39% (p < 0.001), gastrocnemius and soleus muscle mass by 14% and 41% respectively (both p < 0.001), and nitric oxide levels by 100% compared to control (p < 0.001), while reducing triglyceride (p < 0.001), total cholesterol (p < 0.001), LDL (p < 0.05), and increasing HDL (p < 0.001) compared to control, and compared to L-theanine, alpha-GPC, and taurine. Results from this initial investigation indicate that, when compared to the control, L-theanine, alpha-GPC, and taurine, paraxanthine is an effective ingredient for various aspects of sports performance and may enhance cardiovascular health.
... Recent meta-analyses and reviews suggest that CAF increases muscular endurance , muscle strength and power , as well as peak and mean power during a Wingate anaerobic test (Grgic 2018). However, some studies failed to report an ergogenic effect of CAF on anaerobic-based activities (Goldstein et al. 2010;Warren et al. 2010) such as peak torque (Jacobson et al. 1992), isometric maximal force and muscular endurance (Tarnopolsky and Cupido 2000;Plaskett and Cafarelli 2001), maximal dynamic force (Astorino, Rohmann, and Firth 2008;Williams et al. 2008), and peak and mean power during Wingate test (Roberts et al. 2007;Beck et al. 2006;Greer, Morales, and Coles 2006). The ergogenic effect of CAF appears to have an interindividual variability, which may be explained by responsiveness and genetic polymorphisms (Pickering and Kiely 2018;Spineli et al. 2020). ...
Article
Creatine (CRE) and caffeine (CAF) have been used as ergogenic aids to improve exercise performance. The present study reviewed the current evidence supporting the additional use of CAF intake during or after the CRE loading on exercise performance. The search was carried out in eight databases, with the methodological quality of the studies assessed via the QualSyst tool. From ten studies that met the criteria for inclusion, six had strong, three moderate, and one weak methodological quality. CAF was ingested ∼1 h before the performance trial (5–7 mg.kg⁻¹) after a CRE loading period (5–6 days with 0.3 g.kg⁻¹.d⁻¹) in five studies, with the combination CAF + CRE providing additional ergogenic effect compared to CRE alone in three of these studies. Furthermore, CAF was ingested daily during the CRE loading protocol in five studies, with CAF showing additive benefits compared to CRE alone only in one study (3 g.d⁻¹ of CRE during 3 days + 6 mg.kg⁻¹ of CAF for 3 days). The combination CAF + CRE seems to provide additional benefits to exercise performance when CAF is acutely ingested after a CRE loading. There is, however, no apparent benefit in ingesting CAF during a CRE loading period.
... Once the ED/placebo drink was provided to participants, they were instructed to drink it immediately in front of a blinded examiner who ensured that participants drank the entire drink. The time interval (i.e., 60 min) between the consumption of the drink and the start of 3-km running trials was chosen according to previous studies [26,27]. Lastly, the ED had been tested by a certified company (OATC Inc., Seoul, Korea) and was officially certified as a non-caffeinated ED by the Ministry of Food and Drug Safety in South Korea (MFDS FID-2016042480). ...
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This study examined the effects of a non-caffeinated energy drink (ED) that contained calamansi juice, glucose, and taurine on 3-km running performance and recovery. Eleven NCAA Division I middle-distance runners (20.8 ± 1.5 years old) were randomly assigned to consume either the ED or a placebo drink 60 min before 3-km running on a 400-m official track. Performance time and speed were recorded every 500-m interval. Recovery blood lactate concentration (BLC), systolic (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured at baseline, 60-min after ingesting the drinks, and post-running measurements were performed at 1-min, 5-min, and 10-min. Repeated analysis of variance and paired t-test were applied to examine the effects of time, trials, and their interaction on performance and recovery. Statistical significance was set a priori at p < 0.05. No significant difference was observed in performance time and speed between trials (p < 0.05). No interaction effect was found on performance time, speed, recovery BLC, DBP, and HR (p < 0.05). However, an interaction effect for trial by time was observed on SBP (p = 0.01). Recovery SBP continues to decrease from 5-min to 10-min in the ED trial (∆ = −13.9·mmHg) and slightly increased in the placebo trial (∆ = 1.1·mmHg). This study suggests that acute consumption of a calamansi-containing ED can positively impact the SBP recovery but not running performance. Further studies are needed to examine the acute and chronic effects of this ED on exercise performance and recovery among different populations.
... Table 1) was greater than those obtained using other strategies before 1 RM test in trained athletes. These strategies included incorporation of chain-loaded variable resistance into warm up (free-weight back squat: 6.1%) [31], additional eccentric loading (bench press: 3.2%) [20], plyometric depth jumps (free-weight back squat: 3.5%) [32], whole-body vibration exposure (Smith machine half squat: 4.9%) [33], and caffeine supplementation (bench press: 2.1%) [34]. The foregoing suggests that intermittent cooling of the peripheral of the active muscles provides greater benefits than those previously used strategies. ...
Article
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Inter-set peripheral cooling can improve high-intensity resistance exercise performance. However, whether foot cooling (FC) would increase 1 repetition maximum (RM) lower-limb strength is unclear. This study investigated the effect of intermittent FC on 1 RM leg press strength. Ten recreational male lifters performed three attempts of 1 RM leg press with FC or non-cooling (NC) in a repeated-measures crossover design separated by 5 days. FC was applied by foot immersion in 10 °C water for 2.5 min before each attempt. During the 1 RM test, various physiological measures were recorded. The results showed that FC elicited higher 1 RM leg press strength (Δ [95% CI]; Cohen's d effect size [ES]; 13.6 [7.6–19.5] kg; ES = 1.631) and electromyography values in vastus lateralis (57.7 [ 8.1–107.4] μV; ES = 0.831) and gastrocnemius (15.1 [-3.1–33.2] μV; ES = 0.593) than in NC. Higher arousal levels (felt arousal scale) were found in FC (0.6 [0.1–1.2]; ES = 0.457) than in NC. In conclusion, the preliminary findings, although limited, suggest intermittent FC has a potential ergogenic role for recreational athletes to enhance maximal lower-limb strength and may partly benefit strength-based competition events.
... However, Astorino et al. [15] found no effect when examining the same lifts and dosage in resistance trained men. Beck et al. [16] also recorded increases in upper body maximal strength in resistance trained men yet found no change in lower body maximal strength. These findings were confirmed by a meta-analysis examining 10 studies that concluded that caffeine-induced increases in maximal strength appeared to be limited to the upper body [17]. ...
Article
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Caffeine is often used in a variety of forms to enhance athletic performance; however, research regarding caffeine’s effects on strength and power in female athletes is lacking. Therefore, the purpose of this study was to analyze the acute effects of caffeine anhydrous (6 mg/kg of body mass) on jumping performance and maximal strength in female collegiate athletes. Eleven athletes (19.7 ± 0.9 yrs; 166.4 ± 10.2 cm, 67.7 ± 9.4 kg) performed two testing sessions separated by one week, and randomly received caffeine or placebo using a double-blind approach. Heart rate, blood pressure, and tympanic temperature were recorded before athletes received each condition, following 60 min of quiet sitting, and directly after performance testing. Athletes were assessed on unweighted and weighted squat jump height (SJH0, SJH20) and countermovement jump height (CMJH0, CMJH20), isometric mid-thigh pull peak force (IPF), and rate of force development from 0–200 ms (RFD200). Resting systolic blood pressure was significantly greater following caffeine administration compared to a placebo (p = 0.017). There were small, significant differences in SJH0 (p = 0.035, g = 0.35), SJH20 (p = 0.002, g = 0.49), CMJH0 (p = 0.015, g = 0.19), and CMJH20 (p < 0.001, g = 0.37) in favor of caffeine over placebo. However, there was no significant difference in IPF (p = 0.369, g = 0.12) and RFD200 (p = 0.235, g = 0.32) between conditions. Therefore, caffeine appears to enhance jumping performance, but not maximal strength in female collegiate athletes.
... Both the AR and GR are known substrates of PKA [25,26], and thus could potentially be influenced by caffeine supplementation either directly from PKA or indirectly via PKA/MAPK interactions [27]. Since caffeine has been shown to increase muscular endurance [28] increases in contraction volume could potentiate MAPK signaling and subsequently alter non-genomic signaling of the AR and GR [29] since we have shown RE contraction alone can change phosphorylation of AR and GR without changes in exercise induced hormonal responses. Thus, the effect of caffeine supplementation on RE and steroid receptor phosphorylation deserves further elucidation. ...
Article
Purpose Consumption of caffeine or caffeine containing pre-workout supplements (SUPP) augments steroid hormone responses to resistance exercise (RE). However, the activation of glucocorticoid (GR) and androgen receptors (AR) following RE SUPP has not been investigated. The purpose of this study was to determine the influence of a pre-workout supplement on AR and GR phosphorylation following RE. Methods: In a randomized, counter-balanced, double-blind, placebo-controlled, within-subject crossover study, ten resistance-trained males ((X¯±SD, age=22±2.4 yrs, hgt=175±7 cm, body mass=84.1±11.8kg) performed four sets of 8 repetitions of barbell back squats at 75% of their 1-repetition maximum (1-RM) with two minutes of rest between sets and a fifth set of barbell back squats at 60% of 1-RM until concentric failure. A SUPP or flavor and color matched placebo (PL) was consumed 60-minutes prior to RE. Vastus lateralis muscle biopsies were obtained prior to supplementation at rest (BL), and ten minutes post-exercise (POST). Biopsies were analyzed for phosphorylated GR (ser134, ser211, and ser226) and phosphorylated AR (ser81, ser213, ser515, ser650) via western blotting. Results: pGRser134 decreased, and pGRser226 increased following RE (p<0.05) with no difference between conditions (p>0.05). pGRser211 was unchanged after RE (p>0.05). pARser515 increased, and total AR expression decreased after RE (p<0.05) in SUPP only. Testosterone and cortisol were not different between SUPP and PL at POST (p>0.05). Conclusion: RE influences AR and GR phosphorylation, and SUPP minimally influences this response in the early recovery period.
... Caffeine was shown to be ergogenic for muscular endurance in two meta-analyses reporting effect sizes ranging from 0.28 to 0.38 (percent change range: 6 to 7%) [158,218]. However, others have shown that it enhances strength but not muscular endurance [219,220], and when studies have examined multiple strength-muscular endurance tasks, there were benefits across the board [67,221], none at all [98,222], or even impairments in muscular endurance with caffeine use [222,223]. Ingesting caffeine prior to a muscular endurance task is likely to delay muscular fatigue, but these effects are not consistent among all studies. ...
Article
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Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3–6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4–6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.
... The performance enhancing effects of caffeine have been known for over 100 years (Rivers & Webber, 1907), and it is now a well-established ergogenic aid, with performance-enhancing effects confirmed at meta-analysis level . These ergogenic effects are present across a variety of exercise types, including aerobic and muscular endurance, anaerobic power, speed, and jumping performance (Burke, 2008;Glaister et al., 2008;Astorino & Roberson, 2010;Duncan et al., 2013;Da Silva et al., 2015;Polito et al., 2016;Grgic et al., 2018;, whereas its impact on maximum strength is less clear (Beck et al., 2006;Goldstein et al., 2010a;Eckerson et al., 2013). ...
Thesis
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Variation between individuals in response to a stimulus is a well-established phenomenon. This thesis discusses the drivers of this inter-individual response, identifying three major determinants; genetic, environmental, and epigenetic variation between individuals. Focusing on genetic variation, the thesis explores how this information may be useful in elite sport, aiming to answer the question “Is there utility to genetic information in elite sport?” The current literature was critically analysed, with a finding that the majority of exercise genomics research explains what has happened previously, as opposed to assisting practitioners in modifying athlete preparation and enhancing performance. An exploration of the potential ways in which genetic information may be useful in elite sport then follows, including that of inter- individual variation in response to caffeine supplementation, the use of genetic information to assist in reducing hamstring injuries, and whether genetic information may help identify future elite athletes. These themes are then explored via empirical work. In the first study, an internet-based questionnaire assessed the frequency of genetic testing in elite athletes, finding that around 10% had undertaken such a test. The second study determined that a panel of five genetic variants could predict the magnitude of improvements in Yo-Yo test improvements following a standardised training programme in youth soccer players. The third study demonstrated the effectiveness of a panel of seven genetic variants in predicting the magnitude of neuromuscular fatigue in youth soccer players. The fourth and final study recruited five current or former elite athletes, including an Olympic Champion, and created the most comprehensive Total Genotype Score in the published literature to date, to determine whether their scores deviated significantly from a control population of over 500 non-athletes. The genetic panels were unable to adequately discriminate the elite performers from non-athletes, suggesting that, at this time, genetic testing holds no utility in the identification of future elite performers. The wider utilisation of genetic information as a public health tool is discussed, and a framework for the implementation of genetic information in sport is also proposed. In summary, this thesis suggests that there is great potential for the use of genetic information to assist practitioners in the athlete management process in elite sport, and demonstrates the efficacy of some commercially available panels, whilst cautioning against the use of such information as a talent identification tool. The major limitation of the current thesis is the low sample sizes of many of the experimental chapters, a common issue in exercise genetics research. Future work should aim to further explore the implementation of genetic information in elite sporting environments.
... Despite the contradictory results of early investigation on the effect of caffeine on bench press exercise performance (Jacobs et al., 2003;Beck et al., 2006;Astorino et al., 2008), most recent investigations have contributed to establish caffeine's ergogenic effects on bench press performance (Diaz- Lara et al., 2016;Grgic and Mikulic, 2017;Wilk et al., , 2020. However, even the most recent investigation on this topic is difficult to apply to real strength training scenarios as the assessments used in these investigations (e.g., 1 RM, load-velocity curve and strength-endurance tests) are rarely used in © Editorial Committee of Journal of Human Kinetics workouts aimed to obtain strength training adaptations. ...
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Previous investigations have established the ergogenic effect of caffeine on maximal muscle strength, power output and strength-endurance. However, these investigations used testing protocols that do not replicate the structure of a regular strength training session. Thus, the aim of this study was to investigate the effect of acute caffeine ingestion on muscle performance during a simulated velocity-based training workout. In a double-blind, randomized and counterbalanced experiment, 12 participants performed two experimental trials after ingesting 3 mg/kg/b.m. of caffeine or a placebo. The trials consisted of 4 sets of 8 repetitions of the bench press exercise at 70% of their one-repetition maximum performed at maximal velocity. Bar velocity was recorded with a rotatory encoder and force, power output and work were calculated. Regarding the whole workout, caffeine increased mean bar velocity (+7.8%; p=0.002), peak bar velocity (+8.7%; p=0.006), mean force (+1.5%; p=0.002), mean power output (+10.1%; p=0.003) and peak power output (+8.2%; p=0.004) when compared to the placebo. The total work performed in the caffeine trial was superior to the placebo trial (7.01±2.36 vs 6.55±2.20 kJ, p=0.001). These results suggest that the acute intake of 3 mg/kg/b.m. of caffeine before a velocity-based strength workout increased muscle performance and the total work performed across the whole training session. Thus, caffeine can be considered as an effective strategy to enhance muscle performance during the bench press training sessions.
... Most of the studies that failed to demonstrate the ergogenic caffeine potential have incorporated untrained subjects, not specifically accustomed to intermittent-sprint exercise [ 187,[194][195][196]. For example, in the Wingate performance test, previous caffeine consumption (20 mg/kg) by resistancetraining subjects did not affect peak power, mean power, and performance [197]. Another study revealed that caffeine administration (5 mg/kg) significantly increased total power, mean power, and peak power in both trained and untrained subjects, suggesting that caffeine seems to improve performance in short-duration maximal exercises (<5 minutes) when not preceded by prolonged submaximal exercises [179]. ...
Article
Caffeine, a xanthine alkaloid compound, is consumed widely and daily by humans, as it is present in several regular beverages such as tea, coffee, soda beverages, and some drugs. Its consumption triggers arousal and alertness, improves mood, and the release of catecholamines, which induce beneficial effects on human behavior. Nonetheless, caffeine has been related to other beneficial effects such as antioxidant and anti-inflammatory actions that are extremely important to human health, altering the cellular redox and inflammatory status in a dose dependent-manner. Caffeine intake has also shown ergogenic effects, which are attributed to different factors, such as enhanced substrate utilization, fatigue delay, and alertness. As such, caffeine has been consumed by athletes from different sports modalities, with positive and negative effects declared. Although peripheral tissues such as the heart, skeletal muscle, and adipocytes are also impacted, there is a deficit of recognized mechanisms in systemic metabolism when compared to caffeine action in the central nervous system (CNS). This review summarizes the most relevant classical and current literature available regarding the use of caffeine in different metabolic situations, such as oxidative and inflammatory status, as well as anaerobic and aerobic physical exercises. Here, we identified the non-CNS caffeine mechanisms modulation, as most are still unknown or controversial, highlighting its influence in the peripheral system and their essential and crucial impacts on the human’s organism adaptation.
... Caffeine's ergogenic effect has been reported to improve performance by 5.5-8.5% during other repeated-high-intensity efforts in team sports athletes, and by 6-7% during muscular endurance exercise [4,17,43]. Similar to these findings, some investigations have failed to find a significant effect on muscular endurance after caffeine supplementation [18,44,45]. Previous investigations determining the effects of caffeine supplementation on muscular endurance had participants perform a comparatively low number of repetitions (<30) until failure over numerous sets (≥3), separated by rest periods, and these were usually within isolated muscle groups [16,17,35]. ...
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Caffeine’s ergogenic effects persist during various exercise modalities; however, information establishing its efficacy during CrossFit® protocols is limited. This study aimed to determine the effects of caffeine supplementation on CrossFit® performance. Twenty CrossFit®-trained men (age = 26.7 ± 6.2 years, experience = 3.7 ± 2.9 years) were randomized in a double-blind, crossover design. Participants completed two sessions separated by a seven-day washout period, 60 min after consuming 5 mg/kg body mass of caffeine or a placebo. In each session, participants completed as many rounds as possible in 20 min of five pull-ups, 10 push-ups, and 15 air squats. CrossFit® performance was the total number of repetitions completed in 20 min. Paired-samples t-tests were used to compare CrossFit® performance between caffeine and placebo conditions and to test for a potential learning effect between the first and second sessions. CrossFit® performance was not significantly different during the caffeine condition compared to the placebo (468.6 ± 114.7 vs. 466.7 ± 94.3 repetitions, p = 0.861). A significant learning effect was identified between the first and second sessions (452.4 ± 101 vs. 483.8 ± 106.5 repetitions, p = 0.001), with no significant effect of treatment order (p = 0.438). Caffeine’s ergogenic effect were not present during the CrossFit® workout “Cindy”; however, future research should include familiarization sessions and examine other CrossFit® workouts in novice and women participants.
... No systematic trends in kinematics or kinetics were observed across testing sessions; therefore, the single familiarisation session was adequate to mitigate learning effects. To remove biological variation associated with diet (Beck et al., 2006), diurnal variation (Küüsmaa, Sedliak, & Häkkinen, 2015;Pavlović et al., 2018) and fatigue (Howatson, Brandon, & Hunter, 2016), testing was performed at the same time of day and subjects were asked to avoid strenuous activity for 24 h prior to testing and maintain their regular dietary intake avoiding caffeinated foods prior to testing. Thus, it is likely poor reliability of cable put kinetic measures is associated with random biological fluctuation and systematic error associated with calculating force values from displacement-time data. ...
Article
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When new protocols are developed, there is a requirement to investigate test–retest reliability of measures for valid use and interpretation of data in research and practice. Therefore, the aim of this investigation was to determine the inter-day reliability of the cable put and seated rotation assessment protocols. On three occasions, nine resistance-trained men performed cable puts and cable rotations at different loads between 6 and 42 kg on a commercially available cable cross over machine. Load stack movement was recorded using a PT5A linear position transducer from which all kinematic and kinetic variables were calculated. Reliability was excellent for peak velocity and displacement based on intraclass correlation coefficient (ICC) and coefficient of variation (CV) across the majority of loads and movements (cable put: ICC = 0.92 to 0.99, CV = 3.1% to 8.6%; cable seated rotation: ICC = 0.76 to 0.99, CV = −1.7% to 16.1%). However, kinetic variables demonstrated inadequate reliability across the majority of days, loads and movements (ICC = 0.70, CV >10%). It was concluded that peak velocity is a reliable kinematic measure to assess muscular capability from cable put and seated rotation protocols; however, kinetic measures are too variable to provide reliable outputs across testing occasions.
... Taken together, the results demonstrated that CMC contributed to an increase in muscular endurance. This result disagrees with reports by Beck et al. (2006) and Wang et al. (2017) who used CMC as a placebo to evaluate supplementation with caffeine and creatinine respectively on motor endurance. In their studies, no improvement in motor endurance was recorded. ...
Article
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Carboxymethyl cellulose (CMC) is generally believed to be biologically inert, non-toxic and non-allergic. Due to its bio-compatibility, bio-degradability and other rheological properties, it has found various uses in different aspects of human life, bio-medically and industrially; that includes, suspension of physiological extract (as a vehicle), drug delivery system, tissue regeneration, formation of smart materials, hydrogels, bone growth, surgical, ultrasound procedures and foodstuff formulations (thickening, binding), lubricant for drilling in oil industry and as a stabilizer and binder in cosmetic industry. In this study, we investigated the physiological effect of CMC on cognition and motor endurance. Wistar rats were orally administered with CMC, at 5mg/kg, 10mg/kg and 20mg/kg doses while a control group was given normal saline. Cognitive function was evaluated using novel object recognition task while motor endurance function was assessed using forepaw grip test. The results obtained showed that there was no significant difference (p > 0.05) in both working and long-term memory in all the groups when compared to the control. Although, not significant the group receiving 5mg/ml CMC showed a lower preference score (working memory) when compared to other groups. However, at the doses 5 mg/kg and 10 mg/kg, motor endurance was significantly improved. Findings in this study suggest that although CMC may not influence cognition in this study, it may not be completely physiologically inert since it influenced motor endurance which may not be undesirable, more studies should be carried out to ascertain its neurobehavioural activity, while caution is encouraged in its usage.
... Acute ingestion of 3-6 mg per kilogram (mg/ kg) caffeine prior to endurance exercise has been shown to favorably impact fat utilization, reduce perceptions of fatigue, increase one's drive to exercise, and enhance performance [8][9][10]. Similarly, studies employing resistance-training have reported mixed results following pre-exercise caffeine ingestion, with some studies reporting significant increases in force production and muscular endurance [11,12] while others have failed to detect such changes [13,14]. In a recent meta-analysis, Grgic et al. [15] examined the effects of caffeine supplementation in 149 participants across 10 studies and concluded that caffeine supplementation significantly improved muscle strength (standardized mean difference: 0.20, 95% confidence interval [0.03, 0.36], p = 0.023). ...
Article
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The timing of macronutrient ingestion in relation to exercise is a purported strategy to augment muscle accretion, muscle and athletic performance, and recovery. To date, the majority of macronutrient nutrient timing research has focused on carbohydrate and protein intake. However, emerging research suggests that the strategic ingestion of various ergogenic aids and micronutrients may also have beneficial effects. Therefore, the purpose of this narrative review is to critically evaluate and summarize the available literature examining the timing of ergogenic aids (caffeine, creatine, nitrates, sodium bicarbonate, beta-alanine) and micronutrients (iron, calcium) on muscle adaptations and exercise performance. In summary, preliminary data is available to indicate the timing of caffeine, nitrates, and creatine monohydrate may impact outcomes such as exercise performance, strength gains and other exercise training adaptations. Furthermore, data is available to suggest that timing the administration of beta-alanine and sodium bicarbonate may help to minimize known untoward adverse events while maintaining potential ergogenic outcomes. Finally, limited data indicates that timed ingestion of calcium and iron may help with the uptake and metabolism of these nutrients. While encouraging, much more research is needed to better understand how timed administration of these nutrients and others may impact performance, health, or other exercise training outcomes.
... In an investigation by Beck et al. they discovered an increase in bench press strength (onerepetition maximum) yet there was no effect on muscular endurance measured as total volume of weight lifted during an endurance test with 80% of the one-repetition maximum [19]. In agreement with these studies, the current investigation did not find an effect of energy drink consumption on muscular endurance as measured via the maximal number of push-ups. ...
Article
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The psychomotor vigilance test (PVT) measures one’s behavioral alertness. It is a visual test that involves measuring the speed at which a person reacts to visual stimuli over a fixed time frame (e.g., 5 min). The purpose of this study was to assess the effects of an energy drink on psychomotor vigilance as well as a simple measure of muscular endurance (i.e., push-ups). A total of 20 exercise-trained men (n = 11) and women (n = 9) (mean SD: age 32 7 years; height 169 10 cm; weight; 74.5 14.5 kg; percent body fat 20.3 6.2%; years of training 14 9; daily caffeine intake 463 510 mg) volunteered for this randomized, double-blind, placebo-controlled, crossover trial. In a randomized counterbalanced order, they consumed either the energy drink (ED) (product: BANG®, Weston Florida) or a similar tasting placebo drink (PL). In the second visit after a 1-week washout period, they consumed the alternate drink. A full 30 minutes post-consumption, they performed the following tests in this order: a 5-minute psychomotor vigilance test, three sets of push-ups, followed once more by a 5-minute psychomotor vigilance test. Reaction time was recorded. For the psychomotor vigilance test, lapses, false starts and efficiency score are also assessed. There were no differences between groups for the number of push-ups that were performed or the number of false starts during the psychomotor vigilance test. However, the ED treatment resulted in a significantly lower (i.e., faster) psychomotor vigilance mean reaction time compared to the PL (p = 0.0220) (ED 473.8 42.0 milliseconds, PL 482.4 54.0 milliseconds). There was a trend for the ED to lower the number of lapses (i.e., reaction time > 500 milliseconds) (p = 0.0608). The acute consumption of a commercially available ED produced a significant improvement in psychomotor vigilance in exercise-trained men and women.
... A likely explanation for this difference between sexes is that females represent a slightly more complex cohort to conduct caffeine research on, as the use of oral contraceptives [115] and differences in menstrual cycle stage [116] can alter caffeine metabolization speeds, which in turn may alter the ergogenic effects of caffeine. However, a number of studies demonstrate that caffeine has an ergogenic effect in females, both in terms of resistance [117,118] and endurance exercise [119,120]. As such, caffeine is clearly ergogenic for females, but questions remain as to whether there are differences in optimal caffeine strategies between the sexes, especially given the differences in caffeine metabolization speed between males and females. ...
Article
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Caffeine is a widely utilized performance-enhancing supplement used by athletes and non-athletes alike. In recent years, a number of meta-analyses have demonstrated that caffeine’s ergogenic effects on exercise performance are well-established and well-replicated, appearing consistent across a broad range of exercise modalities. As such, it is clear that caffeine is an ergogenic aid—but can we further explore the context of this ergogenic aid in order to better inform practice? We propose that future research should aim to better understand the nuances of caffeine use within sport and exercise. Here, we propose a number of areas for exploration within future caffeine research. These include an understanding of the effects of training status, habitual caffeine use, time of day, age, and sex on caffeine ergogenicity, as well as further insight into the modifying effects of genotype. We also propose that a better understanding of the wider, non-direct effects of caffeine on exercise, such as how it modifies sleep, anxiety, and post-exercise recovery, will ensure athletes can maximize the performance benefits of caffeine supplementation during both training and competition. Whilst not exhaustive, we hope that the questions provided within this manuscript will prompt researchers to explore areas with the potential to have a large impact on caffeine use in the future.
... A number of individual supplements such as creatine, caffeine, and substances related to nitric oxide production are often selected as part of the pre-workout ingredients that have been widely investigated [2,5,6]. Creatine supplementation has shown to increase power output, muscle recovery, lean body mass, and delay fatigue in short duration high power exercises [7]. ...
Article
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Currently there is a lack of research into how women respond to pre-workout supplementation. The effects of supplements on exercise performance in women, specifically to power, must be performed. This study investigated the effects of supplementation on power production and maintenance during a high-intensity cycle ergometry sprint performance, vertical jump performance, and bench press performance in women. It also investigated the effects of supplementation on power production and the maintenance of upper and lower body tasks in women. A total of 23 females (22.9 ± 3.6 years, 175.6 ± 6.5 cm, 86.9 ± 15.1 kg, 19.1 ± 8.4 body fat percentage (BF%) (mean ± std. dev.)) were familiarized with the testing protocol and maximal bench press performances were attained (49.5 ± 15.4kg). Utilizing a double-blind crossover design, subjects completed three trials of: Five countermovement vertical jumps, a high-intensity cycle sprint protocol, which consisted of 10 maximal, five second cycle ergometer sprints. Subjects performed a velocity bench press test, utilizing 80% of their predetermined one repetition maximum (1RM) for 10 sets of three repetitions for maximal speed. For 20 min prior to each trial, the subjects ingested, in a randomized order, a pre-workout supplement (Supp), placebo+150 mg caffeine (Caff), or a placebo (PL). Peak power (PP), mean power (MP), and minimum power (MNP) were recorded for each sprint. Maximal velocity from each set was also recorded. Bike sprint and bench press data were normalized to the placebo trial for analysis. Blood lactate (bLa−) was measured immediately prior to each testing session, within 2 min of the completion of the last cycle sprint and following the bench press test. Bike sprint and bench press testing showed no significant differences through the testing sessions, but did significantly decline over test battery (p < 0.05). Vertical jump performance and lactate levels were not significantly different. Supplementation with a pre-workout supplement or placebo with caffeine 20 min prior to participation showed no positive benefits to performance in female participants.
... Results indicated that acute caffeine supplementation gave rise to improved maximal strength in that performance was increased at the strength levels of the hand grip and bench press 1 RM tests. This improved 1 RM for the bench press is in agreement with results reported for strength trained men [70] and women [71], while improved hand grip strength has also been observed for a higher caffeine dose (6 mg/kg) [46]. These findings are very significant, as hand strength has been linked to performance in combat sport modalities [14,72]. ...
Article
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Caffeine used as a supplement has been shown to improve physical and cognitive performance in several sport modalities due to its effects on the central nervous system. This review assesses the direct effects of caffeine supplementation on performance in combat sports. Using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines, relevant studies were identified through the Medline, Scopus and SPORTDiscus databases. Of 1053 search results, only 9 articles fulfilled the inclusion criteria. Of these, three studies detected no ergogenic effect of caffeine supplementation, while six studies did observe a significant positive effect. Supplementation with 3–6 mg/kg of caffeine was found to increase the glycolytic contribution to energy metabolism during the execution of real or simulated combats, as indicated by elevated blood lactate concentrations. Caffeine intake was also noted to improve levels of strength, power and upper arm muscular endurance. These effects were not paralleled by an increase in the exertion perceived by the athlete.
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Caffeine is one of the most widely consumed drugs in the world. There is a strong belief that caffeine is an ergogenic aid to sports performance. Although much evidence suggests that caffeine may improve endurance exercise performance, questions still remain with regard to its effects on neuromuscular function and brief, high-intensity exercise performance. At the cellular level, caffeine stimulates the central nervous system (CNS), enhances neuromuscular transmission and improves skeletal muscle contractility. The former two effects seem to have facilitative effects on activities which require quick reactions and rapid movements. This is evident in that simple and choice reaction and movement times are reduced following ingestion of small quantities of caffeine. It appears, however, that the caffeine-induced increases in muscle contractility seen in vitro do not translate into improved strength, in vivo. Acute caffeine ingestion does not seem to increase maximal voluntary contractions or maximal power output nor delay fatigue. Thus use of caffeine to improve performance in activities requiring strength and short-term endurance seems unwarrented. Further research is needed before clear conclusions can be draw regarding caffeine's effects on neuromuscular function and high-intensity exercise performance.
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In order to determine the effects of caffeine ingestion on performance and metabolic responses during supramaximal exercise, six healthy volunteers performed the Wingate Anaerobic Test twice. Sixty min before each trial, while in a fasting state, they took capsules containing either caffeine (5 mg/kg) or a placebo, according to a single blind and randomized procedure. Caffeine administration did not significantly change either maximal anaerobic capacity (AC) or power (AP) and power decrease (PD). It did, however, induce significant (p less than 0.05) increases in both catecholamine and blood lactate levels as compared to values obtained after placebo administration. Moreover, maximal blood lactate occurred earlier (p less than 0.05), and lactate output seemed to be greater with caffeine (p less than 0.01). There was a strong correlation, both with and without caffeine, between epinephrine and lactate levels (r = 0.81) and between both AP and AC and lactate levels. These data suggest that caffeine, essentially via epinephrine, modifies glycolytic metabolism but fails to improve performance during the Wingate Anaerobic Test in nonspecifically trained subjects.
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The Wingate anaerobic test was developed at the Department of Research and Sport Medicine of the Wingate Institute for Physical Education and Sport, Israel, during the mid- and late 1970s. Since the introduction in 1974 of its prototype (Ayalon et al. 1974), the Wingate anaerobic test has been used in various laboratories, both as a test that assesses anaerobic performance and as a standardised task that can help analyse responses to supramaximal exercise. The test was designed to be simple to administer, without the need for particularly skilled personnel; inexpensive; used with commonly available equipment, such as the Monark or similar mechanical cycle ergometers; non-invasive; measure muscle performance rather than indirect (biochemical or physiological) variables; feasible for administration to a wide spectrum of the population, including young children and the physically disabled; and, on the assumption that anaerobic performance is a local rather than a systemic characteristic, the test should be applicable to the upper and lower limbs alike. In addition, the test should qualify as objective, reliable, valid, sensitive to improvement or deterioration in anaerobic performance, and specific in reflecting anaerobic performance rather than fitness in general. The new anaerobic test was not designed to be used for the study of basic issues of muscle contractility and muscle fatigue, nor to replace biochemical or histochemical analyses of anaerobic metabolism. The purpose of this article is to review and update some characteristics of the Wingate anaerobic test and the gradual evolution in protocols and interpretation of results. Emphasis will be given to the test's reliability and validity. Data will be presented, based on published and unpublished observations from the author's laboratories at the Wingate Institute and McMaster University, as well as on findings from other laboratories. This review does not analyse all aspects of the Wingate anaerobic test. Some methodological issues have been omitted, as well as issues related to the sensitivity, specificity and applicability of the test; nor does the review include discussion of normative data.
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At present, it is unclear how caffeine induced alterations in neuromuscular function might affect force production and EMG signal characteristics during isometric exercise. These data suggest that acute caffeine ingestion (7 mg/kg) has no significant effect on force production during a maximal isometric hand grip contraction or endurance during a sustained submaximal contraction. Further, maximal motor unit activation, the relationship between submaximal motor unit activation and subsequent force production, and frequency content of the EMG signal were not significantly altered following caffeine ingestion. These results indicate that although caffeine may be a potential ergogenic aid for some activities, its ingestion may not improve performance in activities requiring strength and/or short-term endurance.
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We studied the effect of caffeine on voluntary and electrically stimulated contractions of the adductor pollicis muscle in five adult volunteers. Caffeine (500 mg) was administered orally in a double-blind fashion. Electrical stimulation of the ulnar nerve was performed at 10, 20, 30, 50, and 100 Hz before and after a sustained voluntary contraction held at 50% of the maximal voluntary contraction (MVC). A brief tetanus at 30 Hz was also performed to calculate relaxation rate in the fresh muscle. Contractile properties, relaxation rate, and endurance were then assessed after caffeine and placebo, as well as the response of the fatigued muscle to different frequencies of stimulation. There was no difference in the maximal tension obtained with electrical stimulation (T100) or in the MVC between placebo and caffeine. The tensions developed with electrical stimulation at lower frequencies increased significantly with caffeine ingestion, shifting the frequency-force curve to the left, both before and after fatigue. Mean plasma caffeine concentration associated with these responses was 12.2 +/- 4.9 mg/l. We conclude that caffeine has a direct effect on skeletal muscle contractile properties both before and after fatigue as demonstrated by electrical stimulation.
Article
Caffeine ingestion (3-9 mg/kg body weight) prior to exercise increases performance during prolonged endurance exercise and short-term intense exercise lasting approximately 5 min in the laboratory. These results are generally reported in well-trained elite or recreational subjects. However, there is a lack of well-controlled field studies to determine the applicability of laboratory results to the athletic world. Caffeine does not appear to enhance performance during incremental exercise tests lasting 8-20 min and during sprinting lasting less than 90 s, although research examining sprinting is rare. In addition, the mechanisms responsible for any improvement in endurance and short-term exercise have not been clearly established. The ergogenic effects of caffeine are present with urinary caffeine levels that are below the limit of 12 micrograms/ml allowed by the International Olympic Committee, which raises serious ethical issues regarding the use of caffeine to improve athletic performance. One solution would be to add caffeine to the list of banned substances, thereby requiring athletes to abstain from caffeine ingestion 48-72 hr prior to competition.
Article
This double-blind, repeated-measures study examined the effects of caffeine on neuromuscular function. Eleven male volunteers [22.3 +/- 2.4 (SD) yr] came to the laboratory for control, placebo, and caffeine (6 mg/kg dose) trials. Each trial consisted of 10 x 1-ms stimulation of the tibial nerve to elicit maximal H reflexes of the soleus, four attempts at a maximal voluntary contraction (MVC) of the right knee extensors, six brief submaximal contractions, and a 50% MVC held to fatigue. Isometric force and surface electromyographic signals were recorded continuously. The degree of maximal voluntary activation was assessed with the twitch-interpolation technique. Single-unit recordings were made with tungsten microelectrodes during the submaximal contractions. Voluntary activation at MVC increased by 3.50 +/- 1.01 (SE) % (P < 0. 01), but there was no change in H-reflex amplitude, suggesting that caffeine increases maximal voluntary activation at a supraspinal level. Neither the force-EMG relationship nor motor unit firing rates were altered by caffeine. Subjects were able to hold a 50% MVC for an average of 66.1 s in the absence of caffeine. Time to fatigue (T(lim)) increased by 25.80 +/- 16.06% after caffeine administration (P < 0.05). There was no significant change in T(lim) from pretest to posttest in the control or placebo trials. The increase in T(lim) was associated with an attenuated decline in twitch amplitude, which would suggest that the mechanism is, at least in part, peripheral.
Article
To investigate the effect of caffeine ingestion on short-term endurance performance in competitive rowers. In this randomized double-blind crossover study, eight competitive oarsmen (peak oxygen uptake [VO2peak] 4.7+/-0.4 L x min(-1), mean +/- SD) performed three familiarization trials of a 2000-m rowing test on an air-braked ergometer, followed by three experimental trials at 3- to 7-d intervals, each 1 h after ingesting caffeine (6 or 9 mg x kg(-1) body mass) or placebo. Trials were preceded by a standardized warm-up (6 min at 225+/-39 W; 75+/-7.7% VO2peak). Urinary caffeine concentration was similar before ingestion (approximately 1 mg x L(-1)) but rose to 6.2+/-3.6 and 14.5+/-7.0 mg x L(-1) for the low and high caffeine doses, respectively. Plasma free fatty acid concentration before exercise was higher after caffeine ingestion (0.29+/-0.17 and 0.39+/-0.20 mM for 6 and 9 mg x kg(-1), respectively) than after placebo (0.13+/-0.05 mM). Respiratory exchange ratio during the warm-up was also substantially lower with caffeine (0.94+/-0.09 and 0.93+/-0.06 for the low and high dose) than with placebo (0.98+/-0.12). Subjects could not distinguish between treatments before or after the exercise test. Both doses of caffeine had a similar ergogenic effect relative to placebo: performance time decreased by a mean of 1.2% (95% likely range 0.4-1.9%); the corresponding increase in mean power was 2.7% (0.4-5.0%). Performance time showed some evidence of individual differences in the effect of caffeine (SD 0.9%; 95% likely range 1.5 to -0.9%). Ingestion of 6 or 9 mg x kg(-1) of caffeine produces a worthwhile enhancement of short-term endurance performance in a controlled laboratory setting.
Article
Ingestion of a combination of caffeine (C) and ephedrine (E) prolongs time to exhaustion during high-intensity aerobic exercise. CNS stimulation by C and E was proposed as part of the mechanism for the improvement. It was thought that this arousal might also be of benefit during anaerobic exercise. The purpose of this study was to investigate the effect of C, E, and C+E ingestion on performance of anaerobic exercise. Two groups were used to evaluate the effect of C and E on anaerobic performance. Group 1 (WIN) consisted of 16 healthy untrained male subjects who performed a 30-s Wingate test. Group 2 (MAOD) consisted of 8 healthy untrained male subjects who performed a supramaximal (125%VO(2peak)) cycle exercise trial to exhaustion to determine maximum accumulated oxygen deficit. The trials commenced 1.5 h after ingesting either C (5 mg x kg(-1)), E (1 mg x kg(-1)), a combination of C+E, or a placebo (P). All trials were randomized and double blind. Blood samples were assayed for lactate and glucose post drug ingestion just before exercise, and again 3, 5, and 10 min post exercise. Catecholamines were measured in the preexercise and 10-min postexercise blood samples. Ephedrine increased power output during the early phase of the Wingate test, whereas C increased time to exhaustion and O(2) deficit during the MAOD test. C, E, and C+E increased blood lactate, glucose, and catecholamine levels. The improvement in anaerobic exercise performance is likely a result of both stimulation of the CNS by E and skeletal muscle by C.
Article
The purpose of this study was to examine the effect of repeated doses of caffeine on repeated exercise endurance. METHODS Nine male caffeine users performed exercise rides (ER) to exhaustion at 80% VO(2max) after ingesting a placebo, 5 mg x kg-1 of caffeine, or 2.5 mg x kg-1 of caffeine 1 h before the ER. Two ER were performed weekly on the same day once in the morning (AM) and 5 h later in the afternoon (PM). There were four treatments containing either caffeine or placebo, i.e., trial A representing 5-mg x kg-1 caffeine in the AM and 2.5-mg x kg-1 caffeine in the PM; trial B, which was placebo in both AM and PM; trial C representing 5-mg x kg-1 caffeine in the AM and placebo in the PM; and trial D representing a placebo in the AM and 5-mg x kg-1 caffeine in the PM. The order of the treatment trials was double blind and randomized. Caffeine ingestion significantly increased exercise time to exhaustion in the AM (trial A 24.9 +/- 10.2 min and trial C 21.8 +/- 4.9 vs trial B 18.0 +/- 6.4 min and D 17.7 +/- 4.3 min). This effect was maintained in the PM and greater than placebo (B 18.3 +/- 4.8 min) regardless of whether redosing (trial A 21.5 +/- 8.6 min) or placebo (trial C 21.0 +/- 6.8) followed the initial morning dose. Caffeine dosing in the PM (trial D 22.4 +/- 7.2 min) also increased ER after placebo trial D in the AM. It was concluded that redosing with caffeine after exhaustive exercise in the AM was not necessary to maintain the ergogenic effect of the drug during subsequent exercise 6 h later.
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BAR-OR, O. Testing of Anaerobic Performance by the Wingate Anaerobic Test. Bloomington, IL: ERS Tech, Inc., 1994.
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