Understanding what weight class could be best
for an individual as well. I think that could
be helped by being able to see where's your percentile
ranking based on your weight class. And if you're
seeing somebody's really struggling in their
weight class. to be strong enough you know maybe
is that one where they need to be down or maybe
do do we need to look at some of the nutrition
and recovery aspects or modifying the program
to help them maximize the return on investment
for training and maximize their muscle mass as
well Hi, Zach. Hi, how are you? It's my pleasure
to have you on Evidence Strong Show. If you could
briefly introduce yourself. Yes, my name is Zach
Gillen. I'm an assistant professor in the Department
of Kinesiology at Mississippi State University.
I'm in my sixth year there, and I currently direct
the Resistance Exercise Performance Lab, where
we study a lot of different strength and conditioning
principles, both as it relates to athletes, but
then just your normal everyday individual, young
kids to older adults, and how we can best maximize
training. I'm originally actually from Texas
and did my... bachelor's and master's degree
in exercise physiology at Midwestern State University.
Give them a shout out. Their men's soccer team
just won the national championship. I was at
a youth strength and conditioning company in
Frisco, Texas called DX3 Athlete for about a
year. And then I went and did my PhD at the University
of Nebraska. And when I graduated, was able to
come down here to Starkville, Mississippi and
have me and my wife have been here ever since.
Awesome. So you traveled a lot, huge experience.
You out of the study, we will be talking. about
today and the study is percentile rankings and
normalization of performance for youth international
weightlifting federation world championships
competitors that's a mouthful but you took a
huge amount of data and tried to summarize in
a usable way. So why this study? So one of the
things, like I said, I've had a passion for Olympic
weightlifting, coached people to use weightlifting,
used it in my own training. I believe it's very
important, very, very good training modality
for most individuals, whether athlete or non
-athlete. I can help with strength, with mobility,
range of motion, joint health, everything like
that. And so a lot of the, as I mentioned at
the beginning, a lot of the research that we
do the lab is related to how do we maximize return
on investment for training. Primarily, we focus
on strength and power training, whether it be
your traditional lifts, plyometrics, or Olympic
weightlifting. And so this study is interesting
because most of the studies we do, we have our
lab, participants come into the lab, and we collect
data right there. What I actually did for this
study is I looked up the International Weightlifting
Federation database and pulled the data from
there. of our different lifts or just really
tests in general, vertical jump, 1 .5 mile run,
you know, your squats, everything like that.
You have percentile rankings to where if I'm
training, I know my age category, you know, male
or female, I can see where do I line up. in terms
of my percentile ranking. Am I at the higher
percentile, lower percentile, somewhere in the
middle? But we don't have as much of that available
for the snatch and the clean and jerk and the
total combined. So I was interested in seeing,
all right, can we pull a lot of this data and
actually compile it to develop percentile rankings
so that those who are training can kind of know
where they're at. Coaches and athletes can use
it to know, where am I at? Am I at a good strength?
For my weight class, am I at a good... strength?
And for my age, am I at a good strength? And
so I would like for that to be, because you see
Olympic weightlifting more and more used by everyone
over the last probably 10, 15 years. I've seen
it implemented a lot more beyond just with athletes
and more people are competing in Olympic weightlifting.
So I think it's good to know, okay, where am
I at? Am I at a good percentile ranking? Is my
snatch good? Am I clean and jerk bad or vice
versa? Where could I actually improve a little
bit more? And one of the other things we did
with this stuff, Study two was not just look
at the percentile ranking of the raw total, but
looked at it, everything normalized for body
mass as well, because obviously those who are
heavier, you can just look at records, right?
Heavier weight classes lift more because they
have more muscle mass. They're able to move more
weight because of that additional muscle mass.
So I wanted to look at it, not just for the raw
score, but also based on your body weight, what
you're weighing in at. Are you at a good percentile
ranking? What could you improve upon? Or even...
where maybe people could figure out, is this
the right weight class for me where I can be
highly competitive or would I be better down
a weight class, up a weight class, whatever it
might be. Awesome. So you mentioned a little
bit that you took the data from the IWF website.
How big of an effort was it? And what kind of
data did you pull out? So I ended up pulling
up, for this one we did... I did the most recent
few years of competition, specifically since
they changed the weight class in, I believe it
was 2018. So I used data from 2019, 21, 22, and
2023. I had pulled this data actually before
the 2024 World Championship. For this study,
I specifically took World Championships. I've
seen some other studies recently, some coming
out looking at different competitions as well,
using similar type of... methods of pulling some
of those large data sets. And I ended up deciding,
you know, if people were competing year to year,
I just took the entire. So for 2019, I skipped
over 2020 because of COVID. So didn't have a
whole lot to go off of that year. But for 2019
was the furthest back I went for this one. Just
pulled all that data. Then I came to 2021, pulled
all that data. For this, I did not look at specifically
if this person competed over here. How did they
do in 2021 as well? Although that is another
research question I've been interested in looking
at is, OK, if we get similarities of these people,
these individuals at different competitions,
tracking some of those changes over time for
different groups of people, different weight
classes, seeing if individuals are shifting in
their weight class one way or the other, what
that's doing to their snaps, their clean and
jerk and their total. But for this one, I didn't
actually. eliminate people if it was, hey, they
competed here, so I'm not going to use them over
in 2021 or 22. I left them in that data set just
so I could get a nice large compilation of data,
which for this one, you know, we had 812 records
between the boys and girls as well. So some of
those were repeated, some were unique to each
competition. And what age bracket are we talking
about? So for this one, I specifically did the
youth category, so it's 13 to 17 years. of age.
Because when you're trying to create these reference
normative values, if I take 50 people, that's
not enough to really create normative values.
But when you have several hundred of them, that
becomes very valuable from a statistical side
of things. And I was glad that, you know, I'm
very happy publicly available online because
with this specifically in kids, you see youth
are. using Olympic weightlifting a lot more when
I've coached youth. I've taught them snatch and
clean and jerk. And I think it's good, like you
were saying, for them to know where am I stacking
up, even if they're not, it could just be somebody
they're not competing in Olympic weightlifting,
but they're using it in their programming. And
so wanting to see, are they actually progressing
very well? How does their strength stack up against
other youth who are competing at a high level?
But I have a passion for promoting this type
of lifting as well. in that youth age category.
Let's talk about what type of analysis you decided
to do. So I use a statistical program called
SPSS. So creating the normative values is pretty
easy in that statistical software program. I
put what I want in there and it... spit it back
out for me. One of the unique things we did with
this one, like I said, we looked at the influence
of body mass on the actual lifts, on snatch,
clean and jerk and the total. So with weightlifting,
we know they have the Sinclair coefficient, which
is what is used to determine based on your total,
how are you based on your body mass to try to
normalize that out to get best overall, which
seems effective, but that works for the total,
not for the snatch and clean and jerk individually.
So one of the methods we employed in this one
and I looked at was something called allometric
scaling. And allometric scaling is basically
how we typically have done normalization in terms
of taking my weight. dividing it by my body mass.
Traditional ratio scaling normalization. Well,
that ratio scaling makes the assumption that
there is a linear relationship between both variables.
So if I increase five kilograms of body mass,
my snatch or my clean and jerk will increase
X amount as well. Inherently linear relationship.
So one of the things I did to check for that
to see is ratio scaling actually appropriate.
for this was I did what's called polynomial regression
analysis to see the relationship between snatch
and body weight clean and jerk body weight total
combined and body weight and it's not a linear
relationship you get some quadratic some cubic
relationships meaning I can't just assume that
if my body weight goes up x amount that my lift
will go up X amount. And so, and that's actually
true of a lot of things in the exercise science
and the lifting field, whether it be powerlifting,
Olympic weightlifting, or any other lift out
there, it's not as clean cut as if you increase
this many pounds of muscle mass, you'll increase
this many pounds in your lift. It would be nice
if that were true, but it's not quite that clean
cut. And so actually one of my doctoral advisor
at Nebraska, Dr. Joel Kramer, he had introduced
me to allometric scaling. And one of the first
papers I did during my doctorate, where instead
of taking weight divided by body mass, you actually
create an allometric parameter where I'll take
my lift and then I can raise it to that allometric
parameter. So it's kind of correcting for the
fact that it's not a linear relationship between
those two. And there's a lot of different scientific
fields that use that, and it's become more and
more common. in the exercise science and kinesiology
field, just because things are not as clear cut
as increase a certain number of pounds of muscle
and you increase a certain number of pounds with
your lifts either. That was one of the things
we also want to introduce in this is give something
beyond just the Sinclair coefficient, but we
can give, hey, here are these, one of the tables
on here, I know we had the allometric parameters
where if somebody were to want to, they can simply
use those to see are they in a good strength
for their weight, their current body weight,
and in their weight category as well. The table's
actually the table eight on there, and it has
an allometric parameter you'll see for boys,
for girls, for the snatch, for the clean. and
jerk and for the total lift I need to take the
lift I did and then I just raise it to that allometric
parameter so instead of you know squaring the
number you just replace that with you know whatever
the parameter is so for example if if I was looking
at the snatch and boys the allometric parameter
was 0 .5636 which means I would take their snatch
and raise it to 0 .5636. And that'll give me
my allometrically scaled lift. And you can do
the same for the clean and jerk, for the total,
for boys and for girls as well. And then you
can go with the number you receive. You can go
straight to the other tables you have in the
paper to see where on the percentile they would
be placing. with this lift. Correct. And so if
you look at table six, table six, for example,
has allometrically scaled total. And so I could
see, okay, based on my weight category, where's
my allometrically scaled number at? And so if
you actually look at the, it's got the formula
in, you know, on page three in this one where
it's got the allometrically scaled performance
measure is I take my performance measure divided
by my body mass raised to that parameter. And
then you'll get a number somewhere, hopefully
on that table or looking somewhat similar to
that table as well. All you have to do is plug
into that formula listed on page three in there.
Your stats, for example, stat divided by body
mass raised to the allometric parameter gives
you an allometrically scaled score. Because one
of the things is, and theoretically similar to
the Sinclair coefficient, it wouldn't be the
same number every single year. That coefficient
changes based on what the world record is as
well. And so this would need, here in a couple
of years, you probably need some more updating
with this. But at the very least, it takes a
snapshot right here in time. how I can use this
to look beyond just that Sinclair normalization,
beyond just taking my lift and dividing it by
my current body mass. So hopefully it gets a
little bit more of a pinpoint accuracy on how
good is your strength based on your body mass.
Do you think that the cuts... the lifters some
lifters do between competitions like world championship
where the medals and the placings are very important
also before their career do you think that this
would influence the scaling and the the totals
maybe it possibly could so you know with And
weightlifting, powerlifting, wrestling or sports
that you see a lot of weight cuts in those. And
I always tell people to be cautious with that
because a lot of those last second cuts is really
you're losing water. You're not actually you're
not losing fat or anything like that because
it's too small of a time frame you're trying
to weight cut in. And so you can potentially
put yourself in more of a dehydrated state, especially
if I have to make weight in the morning, which
which thankfully it's in the morning. So if you
if you don't lift till later in the day, you
know, don't eat breakfast or anything. Go in
and then go about your normal day. But at the
same time, you know, I don't want to put myself
in a compromised state. If I'm dehydrated, my
performance is naturally going to be down. Maybe.
can still do as good as i need to but then you
have to ask am i willing to risk that performance
decline with being in more of a compromised state.
And so hopefully, you know, studies like this,
where we're, we had these normative reference
values can help people in the preparation to
where you don't have to go on a cut right beforehand.
I usually recommend to people. And when you talk
about people at world championships and Olympics,
it's a little different than just normal person
in the gym or even doing amateur competitions.
But I usually. I would recommend find a weight
class where you can perform optimally in, and
hopefully you can use some of these data sets
and these normative values to see, am I at a
good competition strength? But also that you
feel comfortable in terms of, I don't feel like
I'm having to starve myself or dehydrate myself,
or I don't feel like I'm having to really pack
in the calories to try to be at the upper end
of that weight class to maximize my muscle mass.
I want people to be at a good performance weight,
but also understand. you start to dip into some
of the health implications to make sure you're
at a good body health weight as well, because
that's also going to influence the psychological
component too. So I hope these types of data
sets can help people in that preparation. Only
time will tell with that. Okay. Are we ready
to look into the results? We could compare what
differences have you found for sexes and for
weight classes. Some other interesting findings
you would have. Yes. Yeah. So the results, heavier
weight classes lifted more than the lighter weight
classes. Not very surprising there. And the boys
tended to be stronger than the girls. If you
also look at that age category, 13 to 17, during
that pubertal window, that's not, when you go
to pre -pubertal kids, it's usually similar strength.
There at that pubertal time, boys were stronger
than girls. So those are some of the unsurprising
results. But when we look at whether it be the
allometrically scaled, Nash -Clean and Jerkin
total, or even just the Sinclair for the total,
what we found was typically boys were stronger
than girls when correcting for body mass. The
difference was. quite as large, but it was still
there. But for both boys and girls, we found
those middle weight classes were the strongest
pound for pound compared to the upper and lower
end weight classes. Part of it is you have more
individuals in those weight classes as well than
at the upper and lower ends of the spectrum.
But the results really showed, like I said, boys
are stronger than girls, which wasn't surprising.
For the raw totals and snatch and clean and jerk,
heavier lifters stronger. But when you actually
correct for body mass. With allometric scaling
or with Sinclair coefficient, those middle weight
classes were the strongest pound for pound. Anything
extra we can pull out of the data? A couple of
things that people can pull out beyond just like
looking at the results and, you know, interpreting
those. I'd say some of the things with the results
is one, coaches and athletes have some data sets,
some normative values to use now, right? Whereas
in Olympic weightlifting, especially in kids
and kids, we don't have a whole lot of normative.
values. And so those comparisons were part of
it. But my initial idea behind this was we need
some normative reference values, some published
standards, you know, not just if somebody pulls
the data and, you know, throws it up on the internet
is good, but we like to also see things, scientific
published standards that we have out here. Those
are always good to go back to. So one, we have
something to use now for the raw scores, the
absolute weight lifted for Your Sinclair coefficient
corrected weight lifted. And then for those allometrically
scaled, so body mass corrected, weights lifted.
So that'd be one of the big results I hope that
has a practical aspect to it of you don't even
need to know any of the math or anything behind
it all. You can just pull up the table. And if
I want to know, hey, how am I based on my allometrically
scaled snatch? Well, I scroll up in the statistical
analysis paragraph. It's got that formula. If
I know their raw score, I take that. And then
I take their body mass. I take raw, weight lifted,
divided by body mass, raised to that allometric
parameter, which is down there in the last table.
Now I have my allometrically scaled score. Or
if a coach doesn't care to do that, they can
still look at just the raw. Here's your snatch,
your clean and jerk, your total. Or the IWF website
actually has a, you can calculate their Sinclair
coefficient right there on the website. So if
you don't even care to do the allometric scaling,
hopefully there's something that a coach and
an athlete can still take away from this. So
let's just clarify. I didn't want to minimize
the huge amount of work and the outcome that
are the tables with normative values. This is
the gold of the paper. There's no doubt about
it. Now, the additional plus of the analysis
you have done is that the coaches are not limited
to only comparing the total. There may be some
other elements, maybe injury, maybe a lifter
comes with some deficiencies in mobility and
it will take time to get them where they have
to be. For example, in jerk, but for snatch and
clean, they are pretty all right. Or the other
combination, but they have one lift that actually
the coach thinks, oh, that could be a reliable
measure or valid measure of their performance,
but it's not at all. So it's very hard to, well,
do I guess the clean and jerk now? No, you actually
provided the data. They can scale the snatch,
let's say, to the body weight of the athlete
converted. into a score and compare if they don't
want to do it i think they are tables for for
raw data too They can actually just take the
snatch as it is in kilograms and see where in
terms of this huge data set of elite lifters,
how their lifter is comparing. Yeah. Yeah, absolutely.
Yeah. So like I said, if they don't care to go
through any of the math behind it, you just want
to know, hey, where's my snatch or my clean and
jerk at? Just look at the table. If you know
what their body weight is or their weight class,
you can just find with the percentile ranking,
go over to their weight class. You know right
where you're at. Awesome. All right. So let's
bring it all together. What would be the message
for coaches from a study? The message for coaches
is one, you know, if you need to know. If an
athlete is making good progress on their strength
based on their weight class, whether it be for
their just raw, you know, snatch, clean and jerk
or total, you can use these data. If you want
to scale it to the body mass or for the total,
you can use the Sinclair coefficient. You have
that capability here for boys and for girls and
across all the weight class categories there.
And we did use all the IWF weight class categories.
I know for the Olympics, they do scale it down
a few weight classes. So it has. everything that
would be on an international competition and
most of our national competitions too that I've
been a part of. One of the things as well is
knowing that understanding what weight class
could be best for an individual as well. I think
that could be helped by being able to see where's
your percentile ranking based on your weight
class. And if you're seeing somebody's really
struggling in their weight class to be strong
enough, you know, maybe is that one where they
need to be down or maybe do we need to look?
Look at some of the nutrition and recovery aspects
or modifying the program to help them maximize
the return on investment for training and maximize
their muscle mass as well. And another thing,
too, it's a takeaway from this. And we've had
other studies where we did it of. Even when we
corrected for body mass, the boys were stronger
than the girls. Usually we all think it's because
of muscle, which is true. Muscle mass, it makes
a big difference between boys and girls, especially
like I said, in that 13 to 17 category, pubertal
development starts to really differ between boys
and girls. But that also speaks to some of the
complexity we talked about earlier. There's a
lot of other things going on in the body during
growth and development that are differentiating
strength between boys and girls, even when I
correct for. body mass. And so, you know, those
are other things that really, I guess that's
the kind of take home for any researchers who
are listening to this. Some of the things that
I think we need to look at a little bit more,
not even just body mass, but let's look at actual
composition, your muscle mass, some of the neural
development and neuromuscular changes. You know,
I think we as researchers need to do our due
diligence so that we can help coaches out there
better know how can I maximize my training for
my athletes. But I hope, you know, there are
people out there. and coaches who at the bare
minimum can use this to see, hey. Am I at a good
strength for my weight class? You know, are my
athletes progressing really well? Do I need to
maybe take a look at this and maybe that'll spark,
hey, maybe I can modify my program or even look
at is this athlete in the right weight class
based on their strength? And especially if they're
really, really struggling in that, you know,
maybe it's drop down a weight class. Maybe it's
bump up a weight class. Maybe it's stay where
you're at. And let's maybe look at the nutritional
aspect to make sure you're getting, you know,
plenty of protein and plenty of recovery. And
how's your sleep? doing things like that as well.
So I hope there can be some takeaway of, you
know, there's a lot of different things people
could gather from this. This is an elite level
competitor. So I would say if you're working
with very amateur level competitors, and like
I said, there is actually one that came out in
2024 that has adult values as well. If I'm working
with amateur competitors, don't necessarily expect
them to right off the bat be at the level of
international worlds. championship competitors,
but at least gives you a gauge to see how are
they stacking up against the best of the best
as well. But don't expect them to be right there
if they're just starting off with Olympic weightlifting.
You can use this to progress them over time or
see how they're changing over time. Sometimes,
especially with young lifters, the important
aspect is also the rate of progression. So they
may start a little bit lower, but they are progressing
pretty fast and they are able to sustain. the
progress. Sometimes athletes who are progressing
really well as youth athletes or juniors are
not necessarily able to get to the elite. lever
in seniors where it's required for many reasons
but i would caution coaches to not use the tables
in a way that is limiting the athlete's potential
so saying oh they are not meeting the percentiles
of elite world championship participants so there's
no point putting effort into them right you know
i would say to remember you know elite level
athletes in any sport you know they're percentage
of a percentage of the population, right? Most
people are not going to be a world's level competitors.
If I'm working with somebody, are they progressing
in a positive trajectory? Do they keep getting,
is their technique getting better? You know,
I always say, especially in kids, first, let's
get the technique down and then we can worry
more about adding some more weight on the barbell.
Are they progressing continuously? And if they're
starting to slow down their progress or, you
know, a lot of people hit a plateau, that's where
do I need to... to revisit the training program,
tweak a few things here and there. One of the
things I've really tried to focus to speaking
people on is also let's not ignore the recovery
aspect of it as well. Like you were mentioning
earlier with people, you never know what's going
on in life. If you're going through a rough stretch
of life, you're not sleeping as well, your nutrition's
down. that could answer why you're hitting a
plateau right there. So maybe it's a keep training,
but I also understand I might not see as much
progress because of what's going on in your personal
life as well. And those are important things
and important issues that people need to deal
with and be able to handle. But don't, you know,
don't look at this and be disappointed while
they're not at the elite level. You know, most
coaches, you know, you work with. athletes who
aren't getting to the Olympics or the World Championships
level, that does not mean your athletes are not
important, right? They're just as important as
that upper echelon of athlete to coach and to
properly train and design those programs or monitor
their progress so that they, because just a kid
seeing themselves get stronger over time, that
can do a lot for their confidence and for their
just health and well -being for the long term
as well. So whether they're going to, you know,
see these elite level numbers or not, you know,
doesn't matter as much as are they progressing?
Are they getting better? You know, are they seeing
themselves get better as well, which is very,
very important from a psychological standpoint,
too. My job as a coach, yes, is to get them better
for the sport. But like you said, it teaches
them some life skills. It teaches them some discipline,
some toughness, because, you know, we all know
life will have its challenges. And if I can learn
some of that discipline and toughness through
how I'm training my body, it can carry over into
how I'm. able to handle things in life. And,
you know, it's important for kids to get that
exposure as well, whether they're playing a sport
or just in the gym, working out and training.
It gives them some of those skills that hopefully
do carry over for them. I agree 100%. I usually
finish with two questions. The first one is,
which one is your favorite, snatch or clean and
jerk? Clean and jerk for me. I used to not like
the snatch as much. Once I finally figured out
the technique, I like it better, but... I'm more
of a clean and jerk fan. I respect that. All
right. And the last question is where people
can find you if they want to be up to date with
your research or maybe ask a question. Yeah.
So one, you can always try to update on our Department
of Kinesiology website, kinesiology .msstate
.edu. Try to usually every semester update with
some of the recent publications we've had. You
can also find me, Zachary Gillen, on LinkedIn.
That's probably where I will post the most on.
I'm in the professional side of my life, whether
it be new articles or students out at the conferences
presenting research. Also on Instagram, I'll
share some of it as well. My Instagram handle
is at ZM Gillen. So ZM is in Michael and then
G -I -L -L -E -N. Awesome. Thank you so much,
Zach, for today. It was a pleasure. Great. Thank
you so much.