DOES CAFFEINE HELP REACTIVE-AGILITY PERFORMANCE?

Abstract

It is well known that the effects of caffeine intake on the central and peripheral nervous system have positive effects on psychomotor function performace. However, studies examining the effects of caffeine on reactive agility are limited in the literature. The main purpose of this study was two fold: 1) to evaluate the effects of acute caffeine ingestion on reactive-agility performance, 2) to examine the effect of acute caffeine use on HRpeak values. A total of 49 healthy, physically active students (nM=25; nF=24) who were studying at Faculty of sports sciences attended the research (xāge = 21.8±2.3 years, xH = 165.6±8.5 cm, xBM = 60.1±10.2 kg). Following familiarization session, all participants was attended to Agility Star Drill Test (ASDT). ASDT was repeated three different times, 48h apart. During each trial, participants consumed 4 mg/kg either regular instant coffee (CAF), or a decaffeinated instant coffee (PLA). While measuring the baseline, the participants were not given any coffee or caffeine-containing food and beverage. Friedman test and Mann-Whitney U tests were used in the analysis of the data. The significance value was accepted as p<0.05. The primarly result of the study showed that caffeine was more effective in reactive-agility test reaction time (RT), than base results (p<0.05), but it was not different than PLA. Secondly, there were no differences in HRpeak values between the trials (p>0.05).

Full text

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DOESCAFFEINEHELPREACTIVE‐AGILITY
PERFORMANCE?
AzizeBingölDiedhiou1andHülyaAndre2
1 Şırnak University, School of Physical Education and Sport, Şırnak, Turkey
2 Yozgat Bozok University, Faculty of Sport Science, Yozgat, Turkey
Azize Bingöl Diedhiou and Hülya Andre
UDC 796.011.5:178
ABSTRACT
It is well known that the effects of caffeine intake on the central and peripheral nervous system have
positive effects on psychomotor function performace. However, studies examining the effects of caffeine on
reactive agility are limited in the literature. The main purpose of this study was two fold: 1) to evaluate the
effects of acute caffeine ingestion on reactive-agility performance, 2) to examine the effect of acute caffeine
use on HRpeak values. A total of 49 healthy, physically active students (nM=25; nF=24) who were studying at
Faculty of sports sciences attended the research (x̄age = 21.8±2.3 years, x̄H = 165.6±8.5 cm, x̄BM = 60.1±10.2
kg). Following familiarization session, all participants was attended to Agility Star Drill Test (ASDT). ASDT
was repeated three different times, 48h apart. During each trial, participants consumed 4 mg/kg either
regular instant coffee (CAF), or a decaffeinated instant coffee (PLA). While measuring the baseline, the
participants were not given any coffee or caffeine-containing food and beverage. Friedman test and Mann-
Whitney U tests were used in the analysis of the data. The significance value was accepted as p<0.05. The
primarly result of the study showed that caffeine was more effective in reactive-agility test reaction time (RT),
than base results (p<0.05), but it was not different than PLA. Secondly, there were no differences in HRpeak
values between the trials (p>0.05).
Keywords: agility, blazepod, caffeine, reaction time, reactive agility
INTRODUCTION
Caffeine is one of the most widely consumed psychoactive ingredient foods and supplements in the
world (Frary, Johnson, & Wang, 2005; Ferré, 2008; Fulgoni III, Keast, & Lieberman, 2015). Caffeine has
been of great interest for many years as it has been proven to support cognitive development. One of the
most important cognitive effects is that it reduces reaction time (RT) in activities that require speed. (
Grosch, 1998; Haskell, Kennedy, Wesnes, & Scholey, 2005; Childs & de Wit, 2006). The effects of caffeine
on performance are linked to both central and peripheral mechanisms. Caffeine is associated with the
blockage of adenosine receptors in the central nervous system, which prevents reduction of neural
activity and increases muscle recruitment (Bazzucchi, Felici, Montini, Figura, & Sacchetti, 2011).
Peripherally, caffeine inhibits phosphodiesterase activity, thereby promoting plasma catecholamine and
glycolysis activity, increasing the energy availability of active muscles during exercise (Davis & Green,
2009). As a result of its central and peripheral effects, caffeine provides an increase in psychomotor
function performance such as agility and attention (Brice & Smith, 2001; Gillingham, Keefe, & Tikuisis,
2004; Tikuisis, Keefe, McLellan, & Kamimori, 2004; van Duinen, Lorist, & Zijdewind, 2005).
Studies conducted today, reveal that cognitive factors such as visual scanning, intuition, perception
and decision making are very important for agility, as well as physical characteristic such as speed,
change of direction and strength. ( Zemková, 2016; Armstrong & Greig, 2018). Agility, which is classified
in different ways by researchers, argues that cognitive factors have a key role in this concept, especially in
new approaches. ( Zemková, 2016; Greig & Naylor, 2017; Armstrong & Greig, 2018). Researchers say that
the methods used to evaluate agility performance mostly measure speed and change of direction
performance, therefore they are insufficient to measure all factors that meet this concept, especially
cognitive factors (Šimonek, Horička, & Hianik, 2016; Zemková, 2016; Zouhal et al., 2018). A model was
created by Young, James, & Montgomery (2002) to represent the sub-components of agility performance.

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This model was later adapted by Young & Sheppard (2006) with minor changes (Sheppard & Young,
2006).
Figure1. Universal agility components (Sheppard & Young, 2006)
According to The European Food Safety Authority, 75 to 150 mg caffeine intake increases alertness
and attention (EFSA Panel on Dietetic Products & Allergies, 2011). There are many studies investigating
the effects of caffeine on agility, RT and speed (Brice & Smith, 2001; Judelson et al., 2005; Lorino, Lloyd,
Crixell, & Walker, 2006; Duvnjak-Zaknich, Dawson, Wallman, & Henry, 2011; Schuda, Thornton, Vitale,
Wright, & Ameres, 2019; Egesoy & Öksüzoğlu, 2020;). However, as mentioned above, agility is not
dependent on a single parameter, on the contrary, it is a feature consisting of many components. In this
regard, to investigate the effects of caffeine on agility, the BlazePod-Agility Star Drill Test (ASDT), which
simultaneously evaluates the RT, speed, visual scanning, and detection features that affect agility, was
applied. In this study, we focused on examining the effect of caffeine on agility, using a higher amount of
caffeine than EFSA claims. In this contex, the aim of this investigation was to find out whether ingestion of
caffeine in the form of instant coffee exerts any influence on agility time performance and observe HRpeak
values of participants during ASDT trials. We hypothesize that ingestion of caffeine in the form of instant
coffee exerts improve reactive-agility performance in physically active individuals.
METHODS
Subjects
A total of 49 healthy, physically active students (nM=25; nF=24) who were studying at Faculty of sports
sciences attended the research (x̄age=21.8±2.3 years, x̄H=165.6±8.5 cm, x̄BM=60.1±10.2 kg). Subjects were
recruited by personal contact. Individuals regularly ingesting greater than 600 mg of caffeine per day
were excluded. Prior to data collection, the University approved all procedures and subjects provided
written informed consent. Throughout testing, procedures adhered to standard national and
international regulations regarding the use of human subjects in research.
Procedure
The cross-over double-blind experiment included a familiarization day with the tests and three
identical experimental trials. In familiarization day, before the study was conducted, participants were
reminded to restrain from all caffeine sources and supplements 48h before the trials and until the end of
the experiment. They were encouraged to train for, avoid alcohol consumption, be adequately hydrated
and sleep at least 8h the day before the experiments. During each trial, participants consumed 4 mg/kg
either regular instant coffee (CAF), or a decaffeinated instant coffee (PLA) from the same manufacturer
(Nestle Nescafe Gold, Bursa, Turkey). While measuring the baseline, the participants were not given any
coffee or caffeine-containing food and beverage. Upon arrival to the laboratory the anthropometric
characteristics of the participants were measured. Participants were then requested to experiment ASDT
for familiarization, one week before the trials and just one time. On the 1st day participants' baseline
values of ASDT were measured. On the 2nd and 3rd trials, the participants applied the test after consuming

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coffee with caffeine (CAF) or non-caffeinated (PLA). Heart rate (HR) were measured (Polar Team 2
telemetric system, Finland) before and during the ASDT. For measurement of resting HR, before the
ASDT, participants were asked to lie comfortably in a supine position and HR was recorded. The highest
HR value during the ASDT was recorded as HR
peak
. On the days of CAF and PLA, the coffee were given to
the participants 60 minutes before the test. Caffeine was mixed with 200 ml of hot water at a rate of
4mg/kg
of participants and has been given as of sugar free. Decaffeinated coffee given as PLA was given in
proportion to the amount of caffeinated coffee for each participant. Immediately after testing, participants
wer asked to rate their perceived exertion (RPE).
Figure2. Test Protocol

AgilityStarDrillTest(Reactive‐agilityTest)
RT of volunteers were measured using the BlazePod™ Trainer Device (Play Coyotta Ltd., Tel Aviv,
Israel). The intraclass coefficient values displayed excellent reliability (r’s ranging from 0.833 to 0.884).
Five pods were placed around the home base pod on the floor. They were approximately 3 m from each
surrounding pod to the base pod. For each participant the measurement started when the researchers
manually touched the "start now" button on the BlazePod phone application. After the start command,
with the end of the "3-2-1-go" warning sound, the sensors started to flash randomly for 60 sec. For the
starting position, participants were asked to stand next to the home base pod and when a surrounding
pod lights up run to tap it out and then run back as quickly as possible to tap out the home base pod.
Participants repeated this action up to the end of the test time.
Figure3. BlazePod-Agility Star Drills Test
Statistical analysis
Descriptive statistics for the variables used in the analysis of the data are shown as mean and standard
deviation. Normality tests of the variables were performed with the Kolmogorov–Smirnov test and it was
observed that the data were not normally distributed. Friedman test and Mann-Whitney U tests were
used in the analysis of the data. The significance value was accepted as p<0.05.

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RESULTS
In Table 1 the mean values of age, height, BM and BMI of the participants’ by gender and total mean
values are presented.

Table1.Descriptive statistic of participants
GenderNx̄age±SD(years)x̄H±SD(cm)x̄BM±SD(kg)x̄BMI ±SD
Female24 21.4±2.5 159.5±5.54 54.66±7.7 21.48±2.9
Male25 22.1±2 171.6±6.53 65.4±9.5 21.96±2.3
Total49 21.8±2.3 165.6±8.5 60.1±10 21.73±2.6
Legend:N‐ number, H‐ height, BM‐ body mass, BMI‐ body mass index
Table2.Results of the participants in different variables for BASE, CAF and PLA trials
VariablesBASECAFPLAχ2p
x̄±SD x̄±SD x̄±SD
HR74.4±13.2 73.7±14 70±11 2.65 .265
HRpeak188.5±9.8 187.8±10 187±8.8 4.33 .114
NH16.28±1.5 16.63±1.6 16.51±1.8 4.18 .123
RT2.22± 0.20** 2.17±0.27** 2.21±0.26 8.61 .013*
RPE7±1.7 7.3±1.7 7.3±1.5 2.10 .349
Legend:CAF- caffeine, PLA‐ placebo, HR‐ Heart rate, HRpeak‐ peak heart rate, NH‐ number of hits, RT‐ reaction
time, RPE‐ rated perceived exertion
** Trials with a statistically significant difference
Table 2 shows that there is no statistically significant difference in HR, HRpeak, NH and RPE values of
the participants between BASE, CAF and PLA trials (p>.05). However, in RT values of participants there is
a statistically significant difference between trials (p<.05). This difference occurs between CAF and BASE
in favor of CAF trial.
Table3.Results of the participants by gender in different variables for BASE, CAF and PLA trials
BASECAFPLA
Genderx̄±SDZpx̄±SDZpx̄±SDZp
HRF73.66±13.93 -.55 .582 69.58±13.63 -1.7 .076 68.83±12.84 -.96 .336
M75.24±12.79 77.73±13.54 71.15±10.5
HRpeakF187.66±10.88 -.25 .802 186.54±12.86 -.42 .674 184.62±10.94 -1.7 .076
M189.3±8.86 189.±6.43 189.32±5.60
NHF15.1±.9 -5.10 .00* 15.7±1.1 -3.8 .00* 15.3±1.2 -4.2 .00*
M17.4±1.2 17.5±1.4 17.6±1.7
RTF2.37±0.16 -4.93 .00* 2.31±0.29 -4.1 .00* 2.34±0.22 -3.7 .00*
M2.08±0.13 2.03±0.14 2.07±0.22
RPEF6.95±2 -.152 .87 7.37±1.71 -.05 .95 7.45±1.69 -.68 .49
M7±1.5 7.4±1.7 7.2±1.4
Legend:CAF- caffeine, PLA‐ placebo, HR‐ Heart rate, HRpeak‐ peak heart rate, NH‐ number of hits, RT‐ reaction
time, RPE‐ rated perceived exertion
* Trials with a statistically significant difference
In Table 3 the mean values of HR, HR
peak, NH, RT and RPE of the participants by gender and
comparison of trials are presented. According to gender comparison there was not statistically significant
difference in HR, HRpeak and RPE values (p>.05), while there was statistically significant difference in NH
and RT values for BASE, CAF and PLA trials (p<.05). When the mean values are examined, it is seen that
this difference was in favor of male participants.

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DISCUSSION
The primary findings of this study are: CAF was more effective in RT during the ASDT than base
results and there was no difference in HRpeak values between trials. Given the specific testing parameters
and research frame of reference, these results suggest that in healthy, rested individuals, consumption of
caffeinated foods and beverages may have an positive effect on reactive-agility.
In the study of Lee et al. (2014) in which they investigated the effect of caffeine on agility T-test result
(6 mg/kg gelatin capsules), no statistically significant difference was found between the agility T-test
results of CAF+PLA and PLA+PLA groups (p>0.05). In another study, in which participants were given
200 mg of caffeine and placebo (Kaczka et al., 2021), no significant difference was found between the
trials in reactive Y-Agility test results (p=0.06). It is well known that caffeine ingestion in doses between
32 and 300 mg improves key aspects of cognitive performance such as attention, alertness, and RT (Snel,
Lorist, & Tieges, 2004; Lorist & Snel, 2008; Nehlig, 2010). However, the limitation of most of the current
studies which is investigating the effect of caffeine intake on agility performance is the use of preplanned
stimuli. It is thought that the participants did not test the effect of reactive-agility in synchronization with
a perceptual component that requires the initiation of movement in a game environment. It should be
noted that while there is general consensus that caffeine improves "low" cognitive functions such as
simple RT, caffeine's effects on "higher" cognitive functions such as problem solving and decision making
are often debated (Gazzaniga, 2000). The ASDT used in the current study included speed, visual reaction
and agility components together, which are the basic components that should be included in agility tests.
Therefore, when compared with many studies in which reactivated agility is tested, it can be said that the
current study tests agility ability similar to the game environment (reaction to unplanned stimuli).
RT values of the current study were examined according to the gender difference. A statistically
significant difference was found for BASE, CAF and PLA trials, and this difference was in favour of male
participants. However, the fact that this difference was seen in the base trial shows that there is a
significant difference between both genders regardless of the CAF and PLA trials. For this reason, the
mean values of CAF and PLA trials were compared with BASE to control the effect on genders. In this case,
it was seen that female participants are more affected by CAF and PLA trials than male participants and
RT decreases more than male participants (F vs. M respectively: CAF: -2.53% vs -2.40% PLA: -1.26% vs -
0.48%).
Previous studies show that caffeine has the effect of promoting sympathetic stimulation (Corti et al.,
2002), which also occurs during physical exercise (Nishijima et al., 2002). However, in this current study
HRpeak results of the participants were examined, and there was not statistically significant difference
between the trials. In the meta-analysis study by Benjamim et al. (2020) they report that the difference in
HRpeak is due to CAF supplementation and not due exercise performance. On the other hand, Gonzaga,
Vanderlei, Gomes, & Valenti (2017), Nelson, Biltz, & Dengel (2014) and Kliszczewicz et al. (2018), they
reported that no difference was found in trials in HRpeak values. Considering the studies in which caffeine
HRpeak changes were not observed, it is thought that adequate cardiovascular stress did not occur in the
study protocols. In the current study, the reason why no difference was observed in HRpeak values
between trials may be due to the absence of cardiovascular stress. Studies investigating the effects of
caffeine on HR still seem to have not reached a consensus.
CONCLUSION
In a conclusion CAF was more effective in RT during the ASDT than base results and there was no
difference in HRpeak values between trials and genders.
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