Rybakova P.D., Miroshnikov A.B. Effect of different doses of caffeine on sensorimotor reactions in freestyle wrestlers: a pilot controlled trial

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Publication date: 15.06.2025
DOI: 10.24412/2782-6570-2025_04_02_3
UDC 663.93; 796.89

EFFECT OF DIFFERENT DOSES OF CAFFEINE ON SENSORIMOTOR REACTIONS IN FREESTYLE WRESTLERS: A PILOT CONTROLLED TRIAL

P.D. Rybakova^1,2, A.B. Miroshnikov¹

¹Russian University of Sport “GTSOLIFK”, Moscow, Russia

²Center for Sports Innovative Technologies and National Team Training, Moscow Department of Sports, Moscow, Russia

Abstract. A wrestler's performance depends on the speed of situation assessment, decision making and reaction accuracy. Caffeine has established itself as an ergogenic agent capable of improving performance. The aim of the study was to evaluate the effect of different doses of caffeine supplement on the speed of sensorimotor reactions in freestyle wrestlers. Representatives of the Moscow men’s freestyle wrestling team (n=7) took part in the study. In a double-blind crossover study, participants took a placebo, a high dose of caffeine (6 mg/kg body weight), a moderate dose of caffeine (3 mg/kg body weight) and a low dose of caffeine (1.5 mg/kg body weight) 45 minutes before testing (Schulte table, Simple Visual-Motor Reaction Test and Choice Reaction Test). The results of the pilot study suggest that caffeine supplementation at doses of 1.5 and 3 mg/kg body weight may have a positive effect on attention span, attention allocation, and choice reaction speed in freestyle wrestlers.

Keywords: caffeine, ergogenic aid, freestyle wrestling, dietary supplement, reaction speed, cognitive processes.

Introduction. Martial arts are popular in Russia and around the world for those engaged and from the point of social and entertaining significance [1, 2]. Thus, a level of compe­titiveness increases, which required additional methods, application of ergogenic aid in particular. Caffeine (1,3,7-trimethylxanthine) is recommended by different international sport communities as a pharmaconutrient improving physical and cognitive working capacity [3-5]. Two meta-analyses showed effectiveness of caffeine in martial arts [6, 7]. They examined working capacity indices among representatives of different martial arts (jujutsu, judo, taekwondo etc.), but less randomized controlled trials (RCTs) are aimed at studying the effect of caffeine on working capacity in wrestling. Wrestling competitions are held in different weight categories and styles. Success depends on a number of motor qualities, such as strength, speed, endurance, flexibility, technique and reaction. Reaction time is a time interval before the stimulus and the corresponding volitional response [8]. Among factors, which define performance of a wrestler, are an ability to assess the situation quickly, decision making and reaction accuracy [9]. Reducing the reaction time may potentially improve effectiveness of offensive and defensive movements and extrapolate the opponent’s movements successfully. Aim of the study was set according to the problem survey: to evaluate influence of different doses of caffeine on speed of sensorimotor reactions in freestyle wrestlers.

Methods and organization. The study was carried out in the laboratory of the Center for Sports Innovative Technologies and National Team Training in cooperation with the Sport Medicine Department of the Russian University of Sport “GTSOLIFK”. The study was conducted in accordance with CONSORT 2025 (Consolidated Standards of Reporting Trail) [10] (fig. 1).

All the participants gave an informed written consent for participation in accordance with the Ethical Standards in Sport and Exercise Science [11]. Before signing the consent, all the participants were informed about the study protocol. The study involved representatives of the Moscow men’s national freestyle wrestling team. Initially, the sample included 13 people. The inclusion criteria were:

а) training experience of at least 6 years and more, as well as qualification not lower than the Candidate for Master of Sports;

b) CYP1A2 (cytochrome P450 1A2) gene variant – in order to participate, the athlete should have the “АС” genotype (“normal metabolizers” [12]), since CYP1A2 variants define speed of caffeine metabolism [13];

c) no restrictions on sports activities. After exclusion from the initial sample, 7 athletes were included in the study. Participants competed in the 2024-2025 season and trained an average of 10 hours per week.

The body composition analysis was carried out with bioimpedance on the Medass ABS-02 analyzer (Medass, Russia) per the manufacturer's recommendations. Body mass (BM) was measured with the Seca769 weights (Seca, Germany), body length – with the Seca222 stadiometer (Seca, Germany).

Fig. 1. The CONSORT flowchart

The anthropometric characteristics of the participants (the data are presented in a form of average ± standard deviation): body mass index (BMI) – 26.6±3.2 kg/m², body length (BL) – 177.4±4.7 cm, body mass (BM) – 83.7±8.5 kg, skeletal muscle mass (SMM) – 35.2±2.6 kg, body fat mass (BFM) – 21.6±3.9%. Average year of the participants – 23.4±3.4 years.

The participants lead a usual lifestyle in terms of diet, training and sleeping routine during the study. A day before testing, the participants restrained from intense physical activity. They were also prohibited from using any supplement a week before testing, as well as from food sources of caffeine (coffee, chocolate, carbonated drinks, etc.) one day before testing.

The study followed a crossover, double blind, placebo-controlled design. Participants and researchers were blinded. Prior to testing, participants visited the laboratory for CYP1A2 gene variant identification, anthropometric assessment, and introduction to the tests. In a double-blind method, participants took placebo, high dose of caffeine (6 mg/kg BM), moderate dose of caffeine (3 mg/kg BM) and low dose of caffeine (1.5 mg/kg BM) 45 minutes before testing, washed down with a glass of water [14]. The capsules contained anhydrous caffeine supplement (BeFirst, Russia) or maltodextrin (Bionova, Russia). The capsules were opaque white, the number of capsules provided to the athlete was always the same (3 capsules) regardless of the caffeine ingestion protocol.

Each test was conducted in the morning, the test subjects could adjust height of the chair and position of the armrests. The subjects were instructed not to use smartphones or other gadgets. Each of the tests was conducted three times, the best attempt was registered. Exposure to external stimuli (noise, bright light) was minimized. A Dell E2424HS monitor (23.8 inches diagonal, 1920x1080 resolution (Dell Inc., USA)) was used.

First, the test subjects performed the Schulte table test – a square matrix with five columns and five rows, in which the numbers from 1 to 25 are placed in a random order. The subjects had the select the numbers in direct order (1 to 25) by clicking on the needed number. The test was performed at https://schultetable.ru/training/.

Then the test subjects performed the Choice Reaction Test, where the participant needed to wait on a signal (black cross) in one of four white squares (e.g., there are four different positions of the black cross, which are considered four different stimuli). Each signal corresponded to a key on the keyboard (‘x’, ‘c’, ‘b’, ‘n’) (fig. 2). Thus, there are four stimulus-reaction associations. The number of presented signals is 10. The test was performed at https://www.psytoolkit.org/lessons/simple_choice_rts.html.

Then the Simple Visual-Motor Reaction Test (SVMR) was performed with the NS-Psychotest complex (Neurosoft, Russia). The subjects were successively shown green light signals, at the appearance of which they were required to press the green button as quickly as possible, making least errors possible. Errors were considered to be: prematurely pressing the button and skipping the signal. The light signal was shown at random moment to exclude the possible formation of temporal reflexes. The intervals between signals were 0.5-2.5 s. The number of stimuli presented was 30.

Fig. 2. Graphic depiction of the Choice Reaction Test.

The participant needed to push the “c” button.

Genetic study. The genetic test was performed in the “Genomed” laboratory (Moscow). In the morning, on an empty stomach, a venous blood sample was taken from the ulnar vein and placed in a test tube with ethylenediaminetetraacetic acid.

Statistical analysis. The statistical analysis was done in STATISTICA 10 (StatSoft, USA). The Wilcoxon’s signed rank test was used to compare different intake protocols between the caffeine supplement and placebo, as well as between different caffeine intake protocols. The results are presented in a form of median [1^st quartile; 3^rd quartile].

Results and discussion. According to the results from the Schulte table test, statistically significant differences were found in the reduction of table processing time when caffeine was administered at doses of 1.5 and 3 mg/kg BM, with differences found at a high level of statistical significance when caffeine was administered at 3 mg/kg BM. No statistically significant differences were found between caffeine doses (table 1).

However, none of the protocols of caffeine intake has not demonstrated statistically signi­ficant reduction of reaction time in the SVMR test. There were no statistically significant differences between caffeine doses (table 2).

According to the results from the Choice Time test results, we have identified statistically significant differences in reducing reaction time when caffeine was administered at a dosage of 3 mg/kg BM. No statistically significant differen­ces were found between caffeine doses (table 3).

Table 1

Schulte table results, Me [Q1; Q3]

Protocol	Result, s
Placebo	66 [51; 80]
Caffeine 1.5 mg/kg BM	59 [50; 77]*
Caffeine 3 mg/kg BM	59 [51; 71]**
Caffeine 6 mg/kg BM	65 [50; 76]

Note: * – statistically significant differences compared to placebo, p<0.05; ** – statistically significant differences compared to placebo, p<0.01; BM – body mass.

Table 2

Simple Visual-Motor Reaction test results, Me [Q1; Q3]

Protocol	Result, ms
Placebo	281 [198;314]
Caffeine 1.5 mg/kg BM	279 [201;341]
Caffeine 3 mg/kg BM	271 [194;323]
Caffeine 6 mg/kg BM	278 [195;336]

Note: * – statistically significant differences compared to placebo, p<0.05; BM – body mass.

Table 3

Choice Time test results (average reaction time) , Me [Q1; Q3]

Protocol	Result, ms
Placebo	440 [403;570]
Caffeine 1.5 mg/kg BM	440 [420;497]
Caffeine 3 mg/kg BM	415 [392;529]*
Caffeine 6 mg/kg BM	437 [410;561]

Note: * – statistically significant differences compared to placebo, p<0.05; BM – body mass.

No side effects were reported by the test subjects after supplement intake.

Effect of caffeine on cognitive functions were thoroughly examined before: it improves cognitive abilities in athletes [15] and military personnel [16], as well as technical and tactical skills in some martial arts [7]. As we know, it is a first placebo-controlled study, which examined effect of changes in caffeine doses on results in tests assessing speed of sensorimotor reactions in freestyle wrestlers. Our total results show that caffeine intake 45 minutes before testing at doses of 1.5 and 3 mg/kg BM may reduce reaction time in the Schulte table test and the Choice Reaction test. It should be noted that the results of RCTs evaluating the effect of caffeine on cognitive functions resulted in different experimental data, which may be related to individual features of caffeine “sensitivity” [17], which, apparently, is genetically determined [18]. Therefore, our study included only so-called “normal metabolizers” of caffeine [12]. [12].

Caffeine (1,3,7-trimethylxanthine) is a methylxanthine alkaloid that has been found to inhibit adenosine A1 and A2a receptors in the central nervous system and increase arousal and psychomotor activity [19]. At doses of ~300 mg (4 mg/kg BM), it improves working capacity with minimal side effects in a wide spectrum of cognitive functions, preventing decrease of vigilance and attention resulting from suboptimal arousal [20]. Interesting that in our pilot study, caffeine dosage of more than 3 mg/kg BM has not improved reaction time, and the participants reported no side effects.

Our results also demonstrate that the supplement intake at dosages of 1.5 and 3 mg/kg BM may have a positive effect on attention span, attention allocation, and choice reaction rate in freestyle wrestlers. Caffeine may be particularly useful under conditions of fatigue (during competition or high-intensity training) in reducing vigilance by improving the above parameters. In a similar context, the use of caffeine may be beneficial for athletes who compete after flying across multiple time zones when their sleep is disrupted [19]. A forced reduction in BM (a reduction of 5% of initial BM or more) may lead to a decrease in reaction time in wrestlers [21]. In this case, caffeine administration may also be appropriate.

Conclusion. The results of our pilot study indicate that compared to placebo the caffeine supplement intake at doses of 1.5 and 3 mg/kg BM may positively influence attention span and allocation, choice reaction rate in freestyle wrestlers. Higher dosage of 6 kg/mg BM did not improve performance in any of the tests. In the SVMR test none of the caffeine dosage caused statistically significant reduction of reaction time. Caffeine intake may be effective for an increase of cognitive working capacity in freestyle wrestling. Additional RCTs on this topic are required.

Conflict of interest. The authors declare no conflict of interest.
Financing. The authors report that they received no funding and all costs of the study were personal contributions of the authors.

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INFORMATION ABOUT THE AUTHORS:
Polina D. Rybakova – Analyst of the Sports Nutritionology Department, Centre for Sports Innovative Technologies, and National Team Training of the Moscow City Sports Department; Post-Graduate Student of the Department of Sports Medicine, Russian University of Sport “GTSOLIFK”, Moscow, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Aleksandr B. Miroshnikov – Doctor of Biological Sciences, Associate Professor, Professor of the Department of Sports Medicine, Russian University of Sport “GTSOLIFK”, Moscow, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

For citation: Rybakova P.D., Miroshnikov A.B. Effect of different doses of caffeine on sensorimotor reactions in freestyle wrestlers: a pilot controlled trial. Russian Journal of Sports Science: Medicine, Physiology, Training, 2025, vol. 4, no. 2(14). DOI: 10.24412/2782-6570-2025_04_02_3