Variability Analysis in Judo Para Athletes With Visual Impairments: Match-Outcome Performance in the Tokyo 2020 Paralympic Games With Evidence From the New Classification System.

Match-related performance analysis in judo Para athletes with visual impairments is important to coaches and staff to identify technical-tactical profiles of their athletes and opponents but also to identify whether there are similar characteristics in each visual class. Thus, this study explores the match-related performance in judo Para athletes and verifies the relationship between performance using the old and new classification systems. The match-derived variables were analyzed using different statistical methods considering a total of 182 matches from the Tokyo 2020 Paralympic Games. The results indicated that performance was affected by sex and degree of impairment. The new classification system seems suitable for grouping Para judo athletes, as it differentiates performance between the two proposed classes (J1 and J2), since athletes from each group compete separately. Furthermore, different variability index measures were correlated with competitive performance, demonstrating a specific performance profile for each sport class in judo.

Is caffeine mouth rinsing an effective strategy to improve physical and cognitive performance? A systematic review.

The aim of this study was to perform a systematic review on the effects of caffeine mouth rinsing on physical and cognitive performance. Following a search through 4 databases, 18 studies were found meeting the inclusion criteria (15 for physical performance and 3 for cognitive performance). All selected studies found an improvement in cognitive performance with caffeine mouth rinse. Four studies found positive effects of caffeine mouthwash on physical performance when repeated during exercise, while one study detected a positive effect with a single mouthwash before exercise, but only in a fasted state. Among these studies that showed positive effects, however, three (2 for physical performance and 1 for cognitive performance) presented fair methodological quality. There was also a variety of methodological approaches in the studies that showed no improvement in physical performance with caffeine mouth rinse, which may have influenced the potential to detect the ergogenic effect of caffeine mouth rinse. Thus, the effects of caffeine mouth rinse on physical performance are mixed, but a potential ergogenic effect might be present in a fasted state and when mouthwash is repeated during exercise. Concerning cognitive performance, caffeine mouth rinse seems to be a beneficial strategy.

Effects of caffeine ingestion on cardiopulmonary responses during a maximal graded exercise test: a systematic review with meta-analysis and meta-regression.

While the effects of caffeine ingestion on endurance performance are well known, its effects on cardiopulmonary responses during a maximal graded exercise test have been less explored. This study systematically reviewed and meta-analyzed studies investigating the effects of caffeine ingestion on cardiopulmonary responses during a maximal graded exercise test. A search was performed in four databases, and study quality was assessed using the PEDro scale. Data reported by the selected studies were pooled using random-effects meta-analysis, with selected moderator effects assessed via meta-regression. Twenty-one studies with good and excellent methodological quality were included in this review. Compared to placebo, caffeine increased peak minute ventilation (SMD = 0.33; p = 0.01) and time to exhaustion (SMD = 0.41; p = 0.01). However, meta-regression showed no moderating effects of dosage and timing of caffeine ingestion, stage length, or total length of GXT (all p > 0.05). Caffeine ingestion did not affect peak oxygen uptake (SMD = 0.13; p = 0.42), peak heart rate (SMD = 0.27; p = 0.07), peak blood lactate concentration (SMD = 0.60; p = 0.09), peak tidal volume (SMD = 0.10; p = 0.69), peak breathing frequency (SMD =0.20; p = 0.23), or peak power output (SMD = 0.22; p = 0.28). The results of this systematic review with meta-analysis suggest that caffeine increases time to exhaustion and peak minute ventilation among the cardiopulmonary variables assessed during GXT.

Training Protocols and Specific Performance in Judo Athletes: A Systematic Review.

ABSTRACT: da Silva, LS, Neto, NRT, Lopes-Silva, JP, Leandro, CG, and Silva-Cavalcante, MD. Training protocols and specific performance in judo athletes: A systematic review. J Strength Cond Res XX(X): 000-000, 2021-The aim of this systematic review was to describe different training protocols (e.g., resistance training, high-intensity interval training [HIIT], sprint IT, standard judo training [SJT], and aerobic training [AT]) used to improve neuromuscular adaptation and performance in specific tests with judo athletes. In addition, comparisons were made of the training protocols in the articles analyzed. The searches were conducted using the electronic databases PubMed/MEDLINE, ScienceDirect, Scopus, and Cochrane. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Search terms included martial arts, judo, physical endurance, physical conditioning, training, strength training, resistance training, IT, HIIT, adults, and young adult. A total of 9,230 articles were initially identified. Based on the inclusion criteria, 19 published studies were selected. Approximately 94.7% of studies analyzed used the traditional judo training method, and 57.9% of the articles analyzed introduced the high-intensity interval protocol, whereas 57.9% of the articles analyzed used strength training, and 31.5% of the articles analyzed used AT. Of the 19 studies analyzed, 3 contained female athletes in their samples, representing 15% of the studies, and 4.3% of the athletes who participated in the analyzed studies were women. In addition, some studies reported interventions with more than 1 training method used throughout the training program. It seems that the HIIT methods and SJT promoted greater effects on physiological and neuromuscular adaptations in judo athletes than other methods.

Tracking 25 years of judo results from the World Championships and Olympic Games: Age and competitive achievement.

We quantified the peak age of judokas during the World Championships (WC) and Olympic Games (OG) according to sex, weight category and competitive achievement and determined the relationship between competition year and athlete age. A retrospective study including 12,005 athletes who took part in the last 16 WC and 6 OG. Athletes were divided by sex, weight category and competitive achievement. Overall, females were younger than males, and older athletes competed at the OG compared to the WC. A weight category effect was also observed, with lighter athletes being younger than heavier athletes (p < 0.05). A competitive achievement effect was found for females, with athletes being defeated in the eliminatory phases being younger than those advancing further in the competitions (p < 0.05). Significant associations (p < 0.05) were shown between competition year and age category for males at the WC and for females at both the WC and OG. In general, lighter athletes are younger than heavier ones (p < 0.05). No difference in age was found  between males concerning their competitive achievement in WC and OG, whereas younger females are defeated in the eliminatory phases (p < 0.05).

Acute and chronic effect of sodium bicarbonate ingestion on Wingate test performance: a systematic review and meta-analysis.

The aim of this study was to perform a systematic review and meta-analysis on the acute and chronic effects of sodium bicarbonate (NaHCO3) ingestion on Wingate performance. Following a search through PubMed, Scopus and Web of Science, 9 studies were found meeting inclusion criteria (6 acute and 3 chronic). Random-effects meta-analysis of standardized mean difference (SMD) for peak and mean power was performed. Study quality was assessed using the QualSyst. Results of the meta-analysis showed that acute ingestion of NaHCO3 did not improve Wingate test peak (weighted average effect size Hedges's g = 0.02, 95%CI: - 0.19 to 0.23, P = 0.87) or mean power (weighted average effect size Hedges's g = 0.15, 95%CI: -0.06 to 0.36, P = 0.92). However, chronic ingestion of NaHCO3 improved Wingate test peak (weighted average effect size Hedges's g = 1.21, 95%CI: 0.83 to 1.42, P = 0.001) and mean power (weighted average effect size Hedges's g = 1.26, 95%CI: 0.96 to 1.56, P = 0.001). Quality assessment of selected articles was classified as strong. This meta-analysis provides evidence that chronic, but not acute, ingestion of NaHCO3 increases both Wingate test peak and mean power.

Para Powerlifting Performance: A Retrospective Analysis Considering Origin of Impairment, Sport Classification, and Sex.

OBJECTIVE: We analyzed the retrospective performance of para powerlifters over 8 yrs considering sex, the origin of impairment, and sport classification of para powerlifting. DESIGN: This retrospective study analyzed data from 6791 (4613 and 2178 for male and female, respectively) individual results from 1634 athletes' performances. We collected absolute load (in kilograms), relative load (in kilogram/body mass), chronological age and origin of impairment (acquired or congenital), and sport classification (leg length difference, limb deficiency, range of movement, impaired muscle power, hypertonia, ataxia, athetosis, and short stature of para powerlifters. RESULTS: Males were stronger than females thorough the years with acquired impairment being stronger than congenital impairment. Para powerlifters with acquired impairment were older compared with congenital impairment over the years. Acquired impairment males won 60% more medals than the congenital group. There was a significant association between competition achievement and sports class classification, with a higher number of medals for limb deficiency than other sports classes. CONCLUSIONS: These results demonstrate that the sex, origin of impairment, and sports classification influence performance of athletes in para powerlifting. Thus, this information can help athletes, coaches, sport managers, and sport institutions involved in the sport of para powerlifting.

Cadet and Junior Performance Is Associated With Senior's World Championship and Olympics Achievement in Judo.

Purpose: We determined whether cadet and junior Judo World Championship participation and medal achievement would predict senior performance at World Championship (WC) and Olympic Games (OG). Methods: We analyzed retrospectively a total of 7780 athletes who competed at the OG and WC in the cadet, junior, and senior between 2009 and 2021. Results: There was an increase in the probability of winning a medal in the senior category (WC and OG, and only WC) ranged from 4.3 to 4.5 for medal-winning cadets compared to non-medalists and this probability remained around 3.3-3.8 for medalists in the male and 5.3-5.4 for the female medalists in cadet WC. Moreover, the chance of winning a medal in the senior category (WC and OG) was 8.1-8.5 times greater for medalists when compared to non-medalists in the junior WC. In turn, the probability of winning a medal in the senior (WC) was 1.5-1.7 times greater for athletes who did not compete in the junior WC. In the OG, the probability of winning a medal was 3.5 greater times for medalists when compared to non-medalists at cadet and junior WC. Conclusion: Thus, being a cadet or junior WC medalist increases the probability of winning a senior WC or an Olympic medal.

Acute effects of sodium bicarbonate ingestion on cycling time-trial performance: A systematic review and meta-analysis of randomized controlled trials.

This study aimed to investigate the isolated effects of NaHCO3 on cycling time-trial performance. Furthermore, we investigated whether the ingestion time of NaHCO3, standardized or individualized based on time to peak, could be effective in improving cycling time-trial performance. A systematic review was carried out on randomized placebo-controlled studies. A random-effects meta-analysis assessed the standardized mean difference (SMD) between NaHCO3 and placebo conditions. Eighteen studies were qualitatively (systematic review) and quantitatively (meta-analysis) analysed concerning mean power output (Wmean) (n = 182) and time performance (n = 201). The reviewed studies showed a low risk of bias and homogenous results for Wmean (I2 = 0%) and performance time (I2 = 0%). Overall, when compared to placebo, the NaHCO3 ingestion improved the Wmean (SMD: 0.42; 95% CI: 0.21-0.63; P = 0.001) and performance time (SMD: 0.22; 95% CI: 0.02-0.43; P = 0.03). Similarly, the NaHCO3 ingestion using a time-to-peak strategy improved the Wmean (SMD: 0.39; 95% CI: 0.03-0.75; P = 0.04; I2 = 15%) and performance time (SMD: 0.34; 95% CI: 0.07-0.61, P = 0.01, I2 = 0%). The present findings reveal that NaHCO3 ingestion has the potential to increase the overall performance time and Wmean in cycling time trials.HighlightsNaHCO3 is an effective strategy to increase cycling time-trial performance.The standardized protocol did not improve the cycling time-trial performance parameters.The individualized time-to-peak NaHCO3 ingestion has a positive effect on time and Wmean during cycling time-trial performance.

Performance of Paralympic Powerlifting Records Holders: An Analysis Considering Origin of Impairment, Sex, and Competitive Level.

OBJECTIVE: This study was conducted to investigate the performance difference for current World (Junior and Senior) and Paralympic (Senior) record holders according to origin of impairment (acquired or congenital), level of competition, and sex and to describe the performance progression of Paralympic Powerlifting records holders. DESIGN: This retrospective cohort study involving 60 current world (20 Junior and 20 Senior) and Paralympic (20 Senior) Para powerlifting record holders with 15 males congenital impairment and 14 acquired impairment, while 18 females were acquired impairment and 9 congenital impairments. RESULTS: The origin of impairment did not influence the absolute and relative load of male and female recordists. However, for males, acquired athletes were older and heavier when compared with congenital athletes, but without differences for females. The absolute load of Junior World recordists was lower in relation to Senior World and Paralympic recordists independently of the sex. Congenital athletes more often reached the world record in the Junior category, while the acquired athletes were the ones who obtained most of the records in senior categories. CONCLUSIONS: Our results show that origin of impairment did not influence the absolute and relative load of current World (Junior and Senior) and Paralympic (Senior) recordists.

Caffeine Combined With Sodium Bicarbonate Improves Pacing and Overall Performance During a High-Intensity Time Trial.

Background: No study has demonstrated the effects of sodium bicarbonate plus caffeine (NaHCO3 + CAF) on power output (PO) distribution (e.g., pacing), physiological parameters and energy system contribution during a 4-km cycling time trial (TT). Thus, we aimed to investigate the effects of NaHCO3 + CAF on pacing, physiological parameters, and energy system contribution during a 4-km cycling TT. Methods: Using a double-blind and counterbalanced design, 10 cyclists performed three ingestion protocols (NaHCO3 + CAF, NaHCO3 and placebo) followed by a 4-km cycling TT. Results: 100 min after substance ingestion, the magnitude of change in blood pH and bicarbonate concentration [HCO3-] for NaHCO3 + CAF (+0.04 ± 0.03 and +5.9 ± 1.6 mmol·L-1, respectively, P < .05) and NaHCO3 (+0.02 ± 0.03 and +4.1 ± 2.0 mmol·L-1, respectively, P < .05) was more pronounced than in placebo (-0.01 ± 0.02 and 0.4 ± 0.9 mmol·L-1, respectively). The increase in plasma lactate concentration was more pronounced in NaHCO3 + CAF than in NaHCO3 and placebo (P < .05). Mean ventilation and carbon dioxide production were higher in NaHCO3 + CAF compared to NaHCO3 and placebo (P < .05). The PO and anaerobic power output were increased at the beginning of the 4-km TT (P < .05) in NaHCO3 + CAF compared to the other two conditions, resulting in an improved overall performance (P < .05). Conclusion: NaHCO3 + CAF results in a higher PO and increased anaerobic contribution and respiratory parameters during a 4-km cycling TT.

Is There an Optimal Interval for Medal Winning Performance in World Para Powerlifting Competition?

ABSTRACT: The aim of the study was to determine the optimal interval between competitions for success in World Para Powerlifting events. A total of 1034 female (age = 34.4 ± 9.1 yrs) and 1,697 male (age = 33.7 ± 8.3 yrs) competition results from international Paralympic powerlifting events conducted between 2014 and 2020 were analyzed. Odds ratios for preparations intervals between competitive events were evaluated considering the dependent variable, earning a medal, and the independent variable, level of competition. There was an increased probability of winning a medal when the preparation interval was in the range of 22-30 wks ( P = 0.004), as compared with less than 11 wks, while competing at World Cup events, whereas for World Championships and Paralympic Games, there was an increased probability of winning a medal when the interval range was 23-31 wks ( P = 0.002) and 40 wks or more ( P = 0.011) compared with less than 23 wks. However, there were no significant differences between preparation intervals for Regional Games/Championships. The Para Powerlifting athletes participating in the World Cup events, World Championships, and Paralympic Games share an optimal interval for success of approximately 21-31 wks and results from the World Championships and Paralympic Games, which can also be optimized with an interval of 40 wks or more.

Relative Age Effect in Judo Competitions: Influence of Age, Weight Category, Sex, and Time Frames.

This study was conducted to determine whether the relative age effect (RAE) is present in different age groups, weight categories, sexes, and across different time frames in international-level judo competition. A total of 9451 judo athletes competing at the Olympic Games and/or World Championships in the Cadet, Junior and/or Senior age groups between 1993 and 2020 were considered. Athletes' birthdate distributions were grouped in four quartiles (Q1: January-March; Q2: April-June; Q3: July-September; Q4: October-December) and compared to a day-corrected theoretical distribution using Chi-squared analysis. Poisson regression was also used to evaluate the ability to explain weekly birth count. RAE was more prevalent in males than females (p < .05), and for Cadets and Juniors compared to Seniors (p < .05). Heavyweight and middleweight categories presented RAEs in Senior and Junior males, while for females it was present in Cadet heavyweights (p < .05). RAE was more prevalent in recent years (2009-2021) for Senior male judo athletes (p < .05). Poisson analysis illustrated some nuanced information, including RAE detection during an earlier time frame, not readily apparent with the traditional analysis.

Caffeine ingestion increases the upper-body intermittent dynamic strength endurance performance of combat sports athletes.

The aim of this study was to investigate the effects of caffeine ingestion on upper-body intermittent strength endurance performance of combat sports athletes. Using a double-blind and placebo-controlled crossover design, ten experienced judo and jiu-jitsu athletes performed an upper-body intermittent strength endurance protocol (four set of judogi dynamic strength endurance test, interspersed by 3-min recovery intervals) 60 min after ingesting either caffeine (5 mg·kg-1) or placebo. Compared with placebo condition, caffeine ingestion significantly increased the total number of repetitions (+ 7%, P = 0.04; d = 0.44) and the maximal isometric handgrip strength (+ 5%, P = 0.03, ηp2 = 0.41). Rating of perceived exertion, heart rate and blood lactate concentration increased linearly throughout the test (P < 0.05), but without significant differences between caffeine and placebo conditions (P > 0.05). Caffeine ingestion improved the upper-body intermittent strength endurance performance and maximal isometric strength of combat sports athletes. This suggests that caffeine could help to maintain high levels of maximal handgrip and endurance strength in upper limbs, especially forearm muscles, which are responsible for maintaining the grip on the opponent's judogi.Highlights Caffeine ingestion improved upper-body intermittent strength endurance of grappling athletes.Caffeine ingestion increased maximal isometric handgrip strength of grappling athletes.Heart rate, lactate concentration or rating of perceived exertion were not affected by caffeine ingestion.Our findings suggest that caffeine could help to maintain high levels of maximal handgrip and endurance strength in upper limbs, especially forearm muscles, which are responsible for maintaining the grip on the opponent's judogi.

More time for judo matches? Analysis of type of techniques, time, scores, and penalties in the Tokyo 2020 Olympic Games.

This study aimed to analyze the distribution of judo matches in the Tokyo 2020 Olympic Games, considering matches in the regular duration (≤4 min) and during the extra time (the golden score) according to sex, scores, penalties, phases of competition, weight categories, and judo techniques. The data were extracted from the Official Results Books of the Olympic Games in Tokyo 2020. The combats were divided in matches that were finished in the regular duration and that were finished by the golden score, with a total of 450 matches. The Chi-square test was used to identify the association between all variables and different groups of matches duration, with the level at p < 0.05. The main results demonstrated significant association, considering sex and frequency of matches in the regular time (χ2 = 6.59; p = 0.010) for female athletes. The majority of matches ended in the 3-4 min (χ2 = 204.16; p < 0.001), scores were mostly awarded in the regular time and penalties in the golden score (χ2 = 48.72; p < 0.001), and few matches ended by the golden score for heavyweight athletes (χ2 = 15.16; p = 0.019). Therefore, a high number of matches ended in the golden score in the Olympic Games Tokyo 2020, with a high number of penalties in this competition.

Can caffeine supplementation reverse the effect of time of day on repeated-sprint exercise performance?

The aim of this study was to evaluate if caffeine can reduce the negative influence of diurnal variations on repeated-sprint performance, in addition to investigating if caffeine in the afternoon would potentiate performance compared with the morning. Thirteen physically active men took part in this randomized, double-blind, placebo-controlled and crossover study. All participants underwent a repeated-sprint ability test (10 × 6 s cycle sprints, with 30 s of rest) at 60 min after ingestion of either 5 mg·kg-1 or placebo under 4 different conditions: morning with caffeine ingestion, morning with placebo ingestion, afternoon with caffeine ingestion, and afternoon with placebo ingestion. Total work, peak power (PP) and anaerobic power reserve (APR) were assessed. Oxygen uptake, heart rate, lactate concentration, and rating of perceived exertion were also measured during the repeated-sprint test. Total work (+8%, d = 0.2, small), PP (+6%, d = 0.2), and APR (+9%, d = 0.2) were significantly higher in the afternoon when compared with morning. However, physiological responses were not different between caffeine and placebo conditions. Repeated-sprint (10 × 6 s cycle sprint) performance was influenced by time of day, with lower performance in the morning compared with the afternoon. However, caffeine supplementation did not prevent the reduction in performance in the morning or improve performance in the afternoon.

Sodium bicarbonate ingestion increases glycolytic contribution and improves performance during simulated taekwondo combat.

PURPOSE: To investigate the effect of sodium bicarbonate (NaHCO3) on performance and estimated energy system contribution during simulated taekwondo combat. METHODS: Nine taekwondo athletes completed two experimental sessions separated by at least 48 h. Athletes consumed 300 mg/kg body mass of NaHCO3 or placebo (CaCO3) 90 min before the combat simulation (three rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration [La-] and rating of perceived exertion (RPE) were measured before and after each round, whereas heart rate (HR) and the estimated contribution of the oxidative (WOXI), ATP (adenosine triphosphate)-phosphocreatine (PCr) (WPCR), and glycolytic (W[La-]) systems were calculated during the combat simulation. RESULTS: [La-] increased significantly after NaHCO3 ingestion, when compared with the placebo condition (+14%, P = 0.04, d = 3.70). NaHCO3 ingestion resulted in greater estimated glycolytic energy contribution in the first round when compared with the placebo condition (+31%, P = 0.01, d = 3.48). Total attack time was significantly greater after NaHCO3 when compared with placebo (+13%, P = 0.05, d = 1.15). WOXI, WPCR, VO2, HR and RPE were not different between conditions (P > 0.05). CONCLUSION: NaHCO3 ingestion was able to increase the contribution of glycolytic metabolism and, therefore, improve performance during simulated taekwondo combat.

Acidosis, but Not Alkalosis, Affects Anaerobic Metabolism and Performance in a 4-km Time Trial.

PURPOSE: This study aimed to determine the effect of preexercise metabolic acidosis and alkalosis on power output (PO) and aerobic and anaerobic energy expenditure during a 4-km cycling time trial (TT). METHODS: Eleven recreationally trained cyclists (V˙O2peak 54.1 ± 9.3 mL·kg·min) performed a 4-km TT 100 min after ingesting in a double-blind matter 0.15 g·kg of body mass of ammonium chloride (NH4Cl, acidosis), 0.3 g·kg of sodium bicarbonate (NaHCO3, alkalosis), or 0.15 g·kg of CaCO3 (placebo). A preliminary study (n = 7) was conducted to establish the optimal doses to promote the desirable preexercise blood pH alterations without gastrointestinal distress. Data for PO, aerobic and anaerobic energy expenditure, and blood and respiratory parameters were averaged for each 1 km and compared between conditions using two-way repeated-measures ANOVA (condition and distance factors). Gastrointestinal discomfort was analyzed qualitatively. RESULTS: Compared with placebo (pH 7.37 ± 0.02, [HCO3]: 27.5 ± 2.6 mmol·L), the NaHCO3 ingestion resulted in a preexercise blood alkalosis (pH +0.06 ± 0.04, [HCO3]: +4.4 ± 2.0 mmol·L, P < 0.05), whereas NH4Cl resulted in a blood acidosis (pH -0.05 ± 0.03, [HCO3]: -4.8 ± 2.1 mmol·L, P < 0.05). Anaerobic energy expenditure rate and PO were reduced throughout the trial in NH4Cl compared with placebo and NaHCO3, resulting in a lower total anaerobic work and impaired performance (P < 0.05). Plasma lactate, V˙CO2, and end-tidal CO2 partial pressure were lower and the V˙E/V˙CO2 higher throughout the trial in NH4Cl compared with placebo and NaHCO3 (P < 0.05). There was no difference between NaHCO3 and placebo for any of these variables (P > 0.05). Minimal gastrointestinal distress was noted in all conditions. CONCLUSION: Preexercise acidosis, but not alkalosis, affects anaerobic metabolism and PO during a 4-km cycling TT.

Correction: Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation.

[This corrects the article DOI: 10.1371/journal.pone.0142078.].

Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation.

OBJECTIVES: The aim of this study was to evaluate the effect of caffeine ingestion on performance and estimated energy system contribution during simulated taekwondo combat and on post-exercise parasympathetic reactivation. METHODS: Ten taekwondo athletes completed two experimental sessions separated by at least 48 hours. Athletes consumed a capsule containing either caffeine (5 mg∙kg-1) or placebo (cellulose) one hour before the combat simulation (3 rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration and rating of perceived exertion were measured before and after each round, while heart rate (HR) and the estimated contribution of the oxidative (WAER), ATP-PCr (WPCR), and glycolytic (W[La-]) systems were calculated during the combat simulation. Furthermore, parasympathetic reactivation after the combat simulation was evaluated through 1) taking absolute difference between the final HR observed at the end of third round and the HR recorded 60-s after (HRR60s), 2) taking the time constant of HR decay obtained by fitting the 6-min post-exercise HRR into a first-order exponential decay curve (HRRτ), or by 3) analyzing the first 30-s via logarithmic regression analysis (T30). RESULTS: Caffeine ingestion increased estimated glycolytic energy contribution in relation to placebo (12.5 ± 1.7 kJ and 8.9 ± 1.2 kJ, P = 0.04). However, caffeine did not improve performance as measured by attack number (CAF: 26. 7 ± 1.9; PLA: 27.3 ± 2.1, P = 0.48) or attack time (CAF: 33.8 ± 1.9 s; PLA: 36.6 ± 4.5 s, P = 0.58). Similarly, RPE (CAF: 11.7 ± 0.4 a.u.; PLA: 11.5 ± 0.3 a.u., P = 0.62), HR (CAF: 170 ± 3.5 bpm; PLA: 174.2 bpm, P = 0.12), oxidative (CAF: 109.3 ± 4.5 kJ; PLA: 107.9 kJ, P = 0.61) and ATP-PCr energy contributions (CAF: 45.3 ± 3.4 kJ; PLA: 46.8 ± 3.6 kJ, P = 0.72) during the combat simulation were unaffected. Furthermore, T30 (CAF: 869.1 ± 323.2 s; PLA: 735.5 ± 232.2 s, P = 0.58), HRR60s (CAF: 34 ± 8 bpm; PLA: 38 ± 9 bpm, P = 0.44), HRRτ (CAF: 182.9 ± 40.5 s, PLA: 160.3 ± 62.2 s, P = 0.23) and HRRamp (CAF: 70.2 ± 17.4 bpm; PLA: 79.2 ± 17.4 bpm, P = 0.16) were not affected by caffeine ingestion. CONCLUSIONS: Caffeine ingestion increased the estimated glycolytic contribution during taekwondo combat simulation, but this did not result in any changes in performance, perceived exertion or parasympathetic reactivation.