Again, for conditions that they cannot control
or conditions somehow forced to do it, they didn't
actually measure the caffeine at the peak of
the concentration at 60 minutes. And they missed
that window that we expect to have the highest
effects exerted on the people. Hi, Zacharias.
It's my pleasure to have you on Evidence Strong
Show. If you could briefly introduce yourself.
Hi, Alex. It's a pleasure as well to be in your
show. So I'm Dr. Zacharias Papadakis, and I'm
an associate professor of exercise physiology
and wellness at Bay University in Miami Shores,
Florida, in the United States. I'm the director
of the undergraduate program in exercise physiology
and also the director of the Human Performance
Laboratory. In that lab, we do a variety of studies
that focus on the lifestyle and mental perspective.
Neurophysiology. We test supplements for ergogenic
effects. And what literally we do, we try to
expose the students to the research pathways,
to learn the material through the hands -on experience.
And the press themselves like to do the best
in that perspective. Awesome. So today the topic
is caffeine. So let's start with some kind of
explanation what caffeine is. So caffeine is
like an ergogenic aid known for its beneficial...
influence on performance. And in this particular
case, we have good evidence that caffeine may
be an encouraging aid for sports like running.
But when it comes to events like jumping, the
events that require power, events that stress
mostly the anaerobic metabolic system in that
case, the knowledge is somehow conflicting. We
evaluate the influence of caffeine on vertical
jump height. One of the things that we discussed
is that we want to make this as applicable as
we can. So we deliver a message to the direct
recipients of this paper will be athletes and
coaches. So we want, even though we use sophisticated
machines to measure the jump height, like force
plates, cameras, we report only basic stuff like
the jump height. And that makes the outcome very
applicable because when we take this to the field
to a strength conditioning coach. coach to maybe
a third trainer to a high schooler. codes, they
don't have force plates. They don't have this
like fancy equipment. So they can do the basic,
like a jump with a chalk, you know, that you
measure your jump height, you put your hand,
then you jump and again, the joke, take the measuring
tape and you measure the distance and you say,
okay, you're an improver, whatever. So that was
the basic concept to try to validate findings
from a previous study that was published in the
State Conditioning Journal, I think maybe 10
years ago. And in that perspective to see if
the caffeine actually works. as the previous
research has found in NCAA athletes. So we tried
to replicate this study to the greatest extent,
meaning that we had the same caffeine consumption.
And for your reference, the NCAA... puts the
maximum allowed dose to be five milligrams per
kilogram of body weight. Because after that,
if you're like more of that, they continue to
be illegal, banned, and then the student athlete
may have some, you know, penalties on that one.
We have a dose response. So with caffeine, not
everybody's going to respond the same. That's
one. Because we have the habitual coffee drinkers,
right? And then the answer is somehow pristine.
Their organs never had the caffeine, so they
may experience this like a... effects of the
caffeine in a greater magnitude compared to somebody
else that is like drinks coffee and a lot every
day, like myself. So what happened with the dose,
they have done like studies going from three
milligrams to five to six to nine, even to 12,
if I recall well, even more. And they have found
that somehow the more you receive, the better
it is, right? So that's one fact. The other fact
that we consider is that the more you get, the
more the GI disturbance you're going to have.
So somehow right now there's a concern. is that
around three to six, the majority of the studies
that examine the caffeine effects for performance,
they have shown that the caffeine -centricogen
effect, at the same time, mitigating any side
effects that caffeine can have. Because if you
go up to, let's say, nine or 12 milligrams per
kilogram of body weight, right, you may have
heart palpation, you have jitters, you may have
headache, you may have a variety of stuff, GI
disturbance, okay? And then when we discuss about
performance, the issue is that you have to get
something to help you. But when you actually
do the task, exercise, play a game or whatever,
don't feel like you're going weird, okay? Don't
have this jitter and all that stuff because that's
going to influence your performance. So even
though right now, as you said, the majority of
the literature says that three to six is the
range, for some reason, NCAA decided that five
is the maximum acceptable dosage. Why is that?
I have no knowledge. I'm guessing because they
may focus on... some specific papers. But as
I said at the beginning of our interview, right
now, the International Libby Committee, the WADA,
they have moved the caffeine to the safe substance
list. So it's not anymore banned. So for me,
again, that was another thing that I want to
write and highlight because I like to advocate
about changing policies is that if right now
we saw that there is no difference, okay, then
either like increase the dosage more than five
or even take it away out of your... ban list
because that doesn't actually make any change
because this is what I saw with my study that
there's no difference in the placebo on the caffeine
group. All right. So it is a little bit of a
mess with policies and what is allowed and where.
So it is complicated for athletes. That's a bad
thing because the clearer the rules, the easier
they are to follow and the safer they are for
the athletes. So that's one problem you're flagging.
Now, going back to your study, I am very interested
in this study because most of my audience is
sports and conditioning and weightlifting, Olympic
weightlifting specific coaches. And the study
you run had... a vertical jump which is an explosive
exercise that you know you prepare yourself then
you explode you jump and that's it gone no more
effort that's all you had measured Olympic weightlifting
is very similar so now how the caffeine will
influence this performance there are not many
studies very specific in this kind of there are
some for running and how long you can endure
the exercise with caffeine versus without but
the type of explosive power based studies are
rare. So let's go into how you design the study.
You have real life in the title of the paper,
which I really, really liked. So tell me about
the setup. Yes. So the setup was pretty much
similar. And when we do study with participants,
right, and we use a term that's the convenient
sample. And when it comes to shooting athletes,
you have to create your own shooting athletes.
So in that sense, we want to have a real life.
study that we're going to use participants, very
university student athletes, that they have been
using the jumps in their training or their practice.
In other words, we use sports that they utilize
the open kinetic chain that they run and jump.
We excluded sports like rowing that they actually,
even though they are powerful athletes, when
they do their rowing movements, they don't actually
jump. So we use a single blind. That means that
the participants, they didn't know if they received
the placebo or not, only we, the researchers,
and it was a random. mild crossover design, meaning
that the same person at one instance received
the placebo. There was a cellulose, like let's
say white part that didn't actually get any indication
that it might be the placebo or the caffeine.
And then after like a while, after like maybe
the next day, as we did in our study, they received
the actual caffeine in the same capsule that
they didn't know which one it was. Okay. So that
was one thing, again, that we didn't change because
of the replication study. The other thing that
we didn't change was the five milligrams per
kilogram of body weight, the dose. So everybody
to receive an individualized dose because some
of the studies that have even shown things or
maybe didn't prove anything, they failed to give
a dose based on the body weight. Imagine you
have somebody that's like weighing 100 kilograms,
you get five grams of caffeine and somebody that
has, let's say, half of their body weight. to
get the same amount of caffeine. The dose is
going to be double for the lighter person, and
then the effects will be double as well. So in
order to have everything somehow controlled and
individualized, all of these studies have to
provide a dose that's somehow controlled by the
body weight. So other thing that we did is to
give this at 60 minutes and test the person at
60 minutes after they had the caffeine or the
placebo. And this was based on the pharmacodynamics.
the caffeine that we know that there is a peak
concentration in the system in 60 minutes. That
again is another issue that many of the studies
they failed to control. And even some studies
like test their person where a little in 60 minutes
or later in 60 minutes. So they missed that time
point that it has been shown that is like the
highest concentration over there. So if it has
the highest concentration, then probably has
the highest magnitude on the actual effect. So
that's the other thing that we did. And because
we wanted this to be very, very applied and practical
in that sense, we decided to use the jump that
is very common in sports like basketball, volleyball,
soccer, even like a softball and baseball. They
jump to get the ball. And then we want to get
accurate data. So in that perspective, we didn't
use the field test measurements. We used the
laboratory measurements. So we had the people
to be on the first plate and then jump. And then
we had the cameras, markers. actually calculate
the jump height. Awesome. Did you test their
jumping before caffeine and after or only after?
So one of the design that we did was to measure
before and after the caffeine for both conditions,
okay? And we did three trials for each participant.
So what happens, another thing that maybe some
studies, they don't have the rigorous design
to evaluate some stuff is they have maybe one
measurement, right? Like maybe after. But if
you do the after measurement, you miss what happened
before the baseline. Then other things that we
did and we control the studies that we use people
that actually have been used caffeine in the
past and they had to feel a question about their
habits. So we knew exactly how much caffeine
they've been taking. Because again, exactly as
I said earlier, is that if somebody has never
taken any caffeine and you give like a similar
of the nervous system, they're going to be ready
to go, right? But, and then I'm going to measure
this before or after I'm going to see a great
marketing of a difference. And then I'm going
to say. that the caffeine works. Well, it works
because the system was in a state that was like
pristine, bridging that perspective, and you
give them something that you don't like 100%.
But if somebody has done that for years, okay,
and if you give them something that's like less
of what they expect, then in a particular case,
for them it would be nothing. It would be like
another day in the park, right? So in that particular
case, we test both, okay, pre and post, and also
we test three times, okay? That's another, like,
let's say, uniqueness. from the study that we
added. And we deviate from the previous protocol
that was previous protocol. They did like two
jumps, if I recall well. And also they had, they
took the, some of the stuff, they take the maximum
performance of the two trials or they take the
average. So when we sat down and discussed about
the design, because... Um, I like stats and I
try to, uh, you know, secure my stats in that
way that the stats somehow are better in that
perspective. I said that we're not going to go
with a maximum number. Okay. And we're not going
to go with the average of the two trials. And
since we have three trials, I'm not going to
do either the max or the average. I'm going to
use a statistical method to allow me account
for the differences, not just between the individuals,
but also the differences of the individual between
the three trials. So I can actually. eliminate
maybe a learning effect because we know if somebody
jumps now and then jumps again back to back,
most of the time, the second jump is always higher
because you have that learning effect, the experience,
you learn better and you do things better. And
then the third one might be more the same or
maybe even higher because of the learning effect.
So, so basically speaking, because I want to
put all that stuff, I use a linear mix model.
So in that way, I counted for differences between
the jumps. I counted the difference between individuals
and I feel that my sense cannot. actually was
the most appropriate to capture, okay, that design
in combination with the lots of sizes that we
had to reach the conclusion that we feel that
it's accurate. Could we go back to participants
for a moment? How many did you have and what
sports and so on? So we had 40 participants.
It was like, I'd say, Division II participants.
And we had students for cross -country, softball,
baseball, basketball, volleyball. soccer. And
those are like, you know, the sports that we
have in our university. We didn't include, let's
say sports like golf that we do have or rowing
because again, their basic locomotion, again,
they don't have any jumping. So we want to have
as much, as much like applicability we could
for selecting our participants. And also everybody
to have pretty much the same experience with
the jumping. So when we discussed about, you
know, the trial order or the learning effect
in that particular case. We knew that pretty
much all the people, they have done in their
lives countless jumps. So they knew how to do
the basic counterman jump or the static jump
that we did. And it wasn't something very unique
for them because they have done that numerous
times, either like in training sessions, in condition
testing, because, you know, some sports like
golf, probably they don't do any of these jumps.
They may do for testing purposes, but it's not
actually part of their own sporting activity
as they do it. What have you found? Yes. have
two types of jump. Okay. One is the kind of jump
and then the static jump. So people will be.
are in this world, they know the difference.
We're like really, really easy to execute. One,
you have your, uh, you start from a squat position
and then you jump, uh, with the standardized,
um, uh, techniques that you put your hands around
your waist. So you don't use your, your hands
to as like propel yourself, like higher jump.
And then they kind of, kind of jump is the next
part of the jump test that we do, uh, regular
and exercise physiology and biomechanics as well
that we use your body as a spring. So you are
from the stand up position and then you. bend
down, then you go up and you, by doing this motion,
you utilize your elastic elements of your muscles.
So like a spring, we expect the static jump to
be lower in terms of height. And then you can
jump to be higher in terms of height because
you use that extra, let's say, power, strength,
whatever you want to call it. What we found is
that we saw a difference that was minimal for
both types of jumps, but it was not significant.
So we found that the males, they jumped higher
than the females. And this is something that
most of the times we agree because of the excess
muscularity that they may have. They can produce
more power. They can jump higher. But in this
case, the... the caffeine didn't alter this gap.
It was the same, right? And then when it comes
to the performance based on the trials, right,
we did see that from going from the first trial
to the second trial, there is somehow kind of
improvement, okay? Regardless of you taking the
placebo or the caffeine condition, right? Showing
that maybe there was like, you know, a warm -up,
training effect that influenced that kind of
improvement. Again, not significant one time.
And that improvement wasn't because of the drug
or the caffeine itself. It was because they learned
that better. So when we see this, this is also,
let's say, politically speaking, we end up saying
that, you know what? Okay, if we use a dose that
is NSA approved, okay, in the legal limits, okay,
probably if you take the caffeine, okay, to increase
your jump, that's not going to happen. But that's
always the bad, right? That if you have individualized
dosing, okay. If you consider maybe genetic things
that we didn't control, okay. Even hormonal moderators
that we didn't control. We had like a female
participants. We didn't control for the menstrual
cycle, but we have plenty of knowledge right
now that shows that hormones don't play any difference
to that from your perspective. But because we
didn't control, we can actually support this
one. But using the literature, we can actually
say that, yes, even though. didn't control it
for the hormones. We didn't have any problem
with that one. So when it comes to this perspective,
maybe different genetic makeup, hormone moderators,
right? They may change somebody's performance
when it comes to caffeine. And we discuss again
performance and explosive performance, like a
junk, something like this, sprints, because we
have way better image, clearer image when it
comes to aerobic performance that we know exactly
that, yes, caffeine is ergogenic. and helps a
lot in this case. Okay, let's bring it all together
and try to give some tips and some take -home
messages for coaches and athletes. So when it
comes to staffing perspective, I think the studies,
they need to have as many as people as they can,
okay? To do before that a power analysis and
then to account for attrition and then to go
even more and don't actually cut the study because
they have maybe a time limitation. I need to
finish the study by that timeline because of
this and that. Okay. They have to focus on the
actual project. They have to have the quality
project. And this is happens. Most of the time
we don't have like an adequate summary size.
Then whenever it comes to coffin, because I have
seen these when I was doing my little view about
the coffin is that many. Again, for conditions
that they cannot control or conditions somehow
forced to do it, they didn't actually measure
the caffeine at the peak of the concentration
at 60 minutes. And they missed a window that
we expect to have the highest effects, okay,
exerted on the people. And then the other thing
about the science, again, tried to use, you know,
maybe the best scan model we have in these particular
cases as the linear mix model to account for
this difference between individuals. So that...
comes with the researchers, right? When it comes
to athletes and coaches, okay, even though my
study didn't show any difference, because I do
recognize that nobody can create a study that's
like the best study with no mistakes. And since
having the evidence from the aerobic literature
that supports the use of caffeine, I would say
since the WADA. International Olympic Committee.
They have removed this as a banned substance.
As long as you're an SA athlete and you are taking
the five milligrams body weight of caffeine,
take it just in case it actually helps you. Okay.
Because when it comes to performance world, you
have to be able to provide your scene athletes,
athletes with the tools to increase their performance.
And as I said, even though my side didn't show
this, okay. Compared to the previous studies,
even though we replicated that, they show that
these guys are thinking they had 20, 22 and they
found differences. And they said that, Hey, take
caffeine because caffeine is going to increase
your jump height. We've had 40, we defined N.
But they had division one athletes, they had
division two athletes. So you see there's not
exactly the same, but I have the feeling, as
I said earlier, that taking like from the aerobic
perspective that helps. Even though the anaerobic
has conflict results and minus the conflict result
based on the literature, I would say as long
as people and cause they can tolerate the, you
know, whatever disturbance they may have by taking
caffeine, stay on the safe limits, okay, and
use it because at the end of the day, they might
be beneficial. Right. And because I showed them
my case, it was beneficial. I don't want to steal
away somebody that may gain something that at
my knowledge, that like a dose is highly tolerable.
Okay. There's no any side effects. It's not going
to harm at any point. Let's say so if somebody
wants to see something, they have to consume
this at 60 minutes before they have to time the
caffin, right? So if there is any beneficial
effect, then that late timing to be right on
the spot. and get it. I wouldn't advise to go
to, you know, a 12, 14 or 15 milligrams per body
weight, because we do know that the highest you
go, more than 9, 12, the side effects are like,
you know, great. And some, again, they have the
different tolerance on how they feel about the
side effects. But if taking account my results
that said, hey, it doesn't work that much and
take some, maybe put you in a risk because, you
know, you have palpitations, you have excessive
heart. I've trained all that stuff. I wouldn't
advise anybody to do it in this particular case.
So summarizing, somebody that actually wants
to improve their performance, they want to be
in the safe NCAA docents, I would say you can
take it and maybe it'll work for you. Two short
questions to finish. The first one is, what is
your favorite exercise? Well, one of the... In
this case, I'm always the worst person to reply
on that one because I like everything. I don't
have any particular exercise. My wife sometimes
asks me, what's your favorite food? I'm a foodie.
I eat everything. I would exercise. I was a student
athlete. I played many sports, mostly basketball,
but I was training the javelin. I was really
good in volleyball. I played a little bit of
soccer. But when it comes to exercise, I enjoy
everything that makes me feel happy and energized.
I mean, right now that, you know, I'm in my 50s,
not every exercise is enjoyable for me right
now and easy for me to do. I remember I went
a year ago to play basketball with our students
for like a good cause. And I was sore for a week
after that. When it comes to exercise, everything
makes me happy. Everything is enjoyable with
people, with other colleagues. Lifting is something
that I like to do right now. After you reach
a certain age, you have to adjust your exercises.
And one of the best things that I found that
worked really nice for me, especially for my
joints, is the swimming. So if I go what's maybe
not my favorite, but most beneficial for my health,
I would say swimming, one, because it keeps my
cardio up. It creates strength training, resistance,
that's helping my joints. And then, you know,
lifting resistance with... different exercises.
Awesome. And the last question is if people want
to follow your work or ask a question, where
should they go online? So online, they can find
us on Instagram. I have Zpavadakis, you know,
account on Instagram and it's mostly the work
that we do in my lab. Of course, they can go
to LinkedIn and they can find like Zacharias
Pavadakis as well. And if they want to, you know,
get short snapshots, whatever we do, again, my
other professional accounts on my ex, you know,
the ex -tutor, Zach Papadakis as well. The other
thing, if you want to see, you know, my research,
you can go to Google Scholar. You can go to the
Orchid ID. Most of the times, if you do a search
and you put Zach Papadakis exercise, Berry University,
you're going to get my institutional website.
And then on the bottom, I have my full CV that
they can download and see. you know, all my links,
all the studies I have done, the experience I
have in different areas. And anybody that has,
you know, any inquiry about, you know, a previous
study and something they want to explore, ask
a question, just drop something on, you know,
Instagram or something, send me an email. Thank
you so much for today. It was a pleasure. Yeah,
that was great.