How does muscle memory work? I mean,  the term gets thrown around so much it's  
How does muscle memory work? I mean,  the term gets thrown around so much it's  

difficult to know what it even means  anymore and depending on who you ask,  
difficult to know what it even means  anymore and depending on who you ask,  

you're going to get completely different  answer. In fact, we already did an entire  
you're going to get completely different  answer. In fact, we already did an entire  

video around the neurological aspect of muscle  memory. Well, today's video is the muscles turn.
video around the neurological aspect of muscle  memory. Well, today's video is the muscles turn.

We're going to see exactly how into what degree  muscles "remember" and we're going to discuss  
We're going to see exactly how into what degree  muscles "remember" and we're going to discuss  

why resistance training might just be one of  the most important things you can possibly do  
why resistance training might just be one of  the most important things you can possibly do  

for your health regardless of your age. It's  going to be one to remember. Let's do this!
for your health regardless of your age. It's  going to be one to remember. Let's do this!

[Intro]
[Intro]

We're really excited  
We're really excited  

to share that we have a sister come thing  called Ava that sells anatomical art like  
to share that we have a sister come thing  called Ava that sells anatomical art like  

this one and this one and this one which  is mine and Geoffrey's personal favorite  
this one and this one and this one which  is mine and Geoffrey's personal favorite  

because we have taste and Jonathan does  not. If you're interested and want to  
because we have taste and Jonathan does  not. If you're interested and want to  

support the channel, we'll leave  a link in the description below.
support the channel, we'll leave  a link in the description below.

Skeletal muscle tissue doesn't divide,  meaning that you're born with as many  
Skeletal muscle tissue doesn't divide,  meaning that you're born with as many  

muscle cells as you're ever going to have in  your entire life or at least that's been the  
muscle cells as you're ever going to have in  your entire life or at least that's been the  

commonly accepted view for decades. More  recent studies are starting to show that  
commonly accepted view for decades. More  recent studies are starting to show that  

there are some interesting exceptions  to this rule but they are exceptions  
there are some interesting exceptions  to this rule but they are exceptions  

and by far and larged, it still seemed  to be accurate that they don't divide.
and by far and larged, it still seemed  to be accurate that they don't divide.

So, if they don't divide when a skeletal muscle  gets bigger what's really happening is those  
So, if they don't divide when a skeletal muscle  gets bigger what's really happening is those  

pre-existing cells are becoming hypertrophic.  They are increasing in volume. You see,  
pre-existing cells are becoming hypertrophic.  They are increasing in volume. You see,  

skeletal muscle is unique in that the cells  are multi-nucleated, meaning that one cell  
skeletal muscle is unique in that the cells  are multi-nucleated, meaning that one cell  

can have hundreds to thousands of nuclei  to help regulate its cellular functions.
can have hundreds to thousands of nuclei  to help regulate its cellular functions.

This process begins in utero during embryological  development. You have these in individual cells  
This process begins in utero during embryological  development. You have these in individual cells  

called myocytes that fuse together to create  one single gigantic enormous skeletal muscle  
called myocytes that fuse together to create  one single gigantic enormous skeletal muscle  

cell. The fancy word for this is Syncytium  and that's where single cells fuse together  
cell. The fancy word for this is Syncytium  and that's where single cells fuse together  

to create a larger cell with various components  that are all working together for a single cause.
to create a larger cell with various components  that are all working together for a single cause.

Now, the reason I'm telling you this  is just to provide context as to how  
Now, the reason I'm telling you this  is just to provide context as to how  

skeletal muscle cells become multi-nucleated  in the first place. The real question we're  
skeletal muscle cells become multi-nucleated  in the first place. The real question we're  

pursuing here is what happens to that cell  during muscle hypertrophy. When hypertrophy  
pursuing here is what happens to that cell  during muscle hypertrophy. When hypertrophy  

occurs in any cell, there is going to be  an increase in intracellular components.
occurs in any cell, there is going to be  an increase in intracellular components.

Now, you're gonna have to forgive me for this  because this is an absolute terrible drawing,  
Now, you're gonna have to forgive me for this  because this is an absolute terrible drawing,  

I'm not an artist but the orange  and pink dots are actually meant  
I'm not an artist but the orange  and pink dots are actually meant  

to represent intracellular components such  as lysosomes, peroxisomes, mitochondria and  
to represent intracellular components such  as lysosomes, peroxisomes, mitochondria and  

for skeletal muscle cells that would include  the contractile proteins called Sarcomeres.
for skeletal muscle cells that would include  the contractile proteins called Sarcomeres.

Well, since the late 1800s, it's been thought  that a nucleus has what's called a sphere of  
Well, since the late 1800s, it's been thought  that a nucleus has what's called a sphere of  

influence. That means a nucleus is only capable  of supporting a specific cellular volume. So,  
influence. That means a nucleus is only capable  of supporting a specific cellular volume. So,  

that means there's an actual size limit  for cells because if it gets too big,  
that means there's an actual size limit  for cells because if it gets too big,  

the nucleus can't handle it and  that cell is in a ton of trouble.
the nucleus can't handle it and  that cell is in a ton of trouble.

So, you're probably wondering "Well, then how  on Earth does a skeletal muscle cell increase  
So, you're probably wondering "Well, then how  on Earth does a skeletal muscle cell increase  

in size when you're working out and it becomes  hypertrophic?" There's a size limit. How does that  
in size when you're working out and it becomes  hypertrophic?" There's a size limit. How does that  

even happen? Well, the answer is that the skeletal  muscle cell steals nuclei from other cells.
even happen? Well, the answer is that the skeletal  muscle cell steals nuclei from other cells.

Real quick I want to make the sponsor of  today's video Athletic Greens. Athletic  
Real quick I want to make the sponsor of  today's video Athletic Greens. Athletic  

Greens is a nutritional company that  makes the nutritional drink, AG1,  
Greens is a nutritional company that  makes the nutritional drink, AG1,  

which is far more than just a greens drink and  has become a morning staple for me. AG1 has 75  
which is far more than just a greens drink and  has become a morning staple for me. AG1 has 75  

different ingredients which includes vitamins,  minerals, superfoods probiotics and adaptogens.
different ingredients which includes vitamins,  minerals, superfoods probiotics and adaptogens.

I just turned 35, which is still very young  in the grand scheme of things but my body's  
I just turned 35, which is still very young  in the grand scheme of things but my body's  

finally starting to feel old for the first time  and it's extraordinarily depressing. I mean, look,  
finally starting to feel old for the first time  and it's extraordinarily depressing. I mean, look,  

in the past five years alone I've discovered I  have severe degenerated discs in my low back,  
in the past five years alone I've discovered I  have severe degenerated discs in my low back,  

I have a literal broken back, I have an abnormally  long colon that is all twisted and turned around,  
I have a literal broken back, I have an abnormally  long colon that is all twisted and turned around,  

I grew scar tissue randomly, we still don't  know how, that blocked off my small intestine  
I grew scar tissue randomly, we still don't  know how, that blocked off my small intestine  

nearly killing me and this last one's actually  admittedly much smaller but I think I'm starting  
nearly killing me and this last one's actually  admittedly much smaller but I think I'm starting  

to get plantar fasciitis and it's really kind  of painful but AG1 is not going to fix any of  
to get plantar fasciitis and it's really kind  of painful but AG1 is not going to fix any of  

those and they don't claim to but what AG1  can do is provide me with the essential and  
those and they don't claim to but what AG1  can do is provide me with the essential and  

important nutrition that best positions me to  adapt and overcome these health issues on my own.
important nutrition that best positions me to  adapt and overcome these health issues on my own.

All you do is take one scoop and add  it to eight ounces of water and then  
All you do is take one scoop and add  it to eight ounces of water and then  

shake vigorously. It's super important.  I mean, it's not actually a part of the  
shake vigorously. It's super important.  I mean, it's not actually a part of the  

instructions but it makes me feel happy  inside which is all that matters and then  
instructions but it makes me feel happy  inside which is all that matters and then  

from there you're just going to take  a drink and carry on with your day.
from there you're just going to take  a drink and carry on with your day.

I mean, I'm the type of guy that is  all about effortless daily habits. So,  
I mean, I'm the type of guy that is  all about effortless daily habits. So,  

knowing that a significant amount of  my Essential daily nutrition has been  
knowing that a significant amount of  my Essential daily nutrition has been  

handled first thing in the morning is a huge  weight off my shoulders. If you're interested,  
handled first thing in the morning is a huge  weight off my shoulders. If you're interested,  

visit athleticgreens.com/humananatomy  and they're going to give our audience  
visit athleticgreens.com/humananatomy  and they're going to give our audience  

a one year free supply of immune supporting  vitamin D3, Plus K2 and 5 free travel packs  
a one year free supply of immune supporting  vitamin D3, Plus K2 and 5 free travel packs  

with your first purchase. Go ahead and  find that link in the description below.
with your first purchase. Go ahead and  find that link in the description below.

In 1961, stem cells were discovered that had the  ability to fuse with skeletal muscle cells and  
In 1961, stem cells were discovered that had the  ability to fuse with skeletal muscle cells and  

contribute their nuclei. They were called  Satellite Cells. Now, normally they exist  
contribute their nuclei. They were called  Satellite Cells. Now, normally they exist  

in this state of pause called Quiescence and  what they require is a signal to activate. Now,  
in this state of pause called Quiescence and  what they require is a signal to activate. Now,  

this signal could come from say like an anabolic  steroids such as testosterone or it could also  
this signal could come from say like an anabolic  steroids such as testosterone or it could also  

come from tissue injury, say through resistance  training but if these cells become activated,  
come from tissue injury, say through resistance  training but if these cells become activated,  

what happens is a daughter cell will fuse  with the skeletal muscle cell give its nuclei.
what happens is a daughter cell will fuse  with the skeletal muscle cell give its nuclei.

The other daughter cell will then pull back and  repopulate the satellite pool and go back into  
The other daughter cell will then pull back and  repopulate the satellite pool and go back into  

that state of quiescence waiting for another  signal. Now this is all great and dandy but  
that state of quiescence waiting for another  signal. Now this is all great and dandy but  

now we have a new question on our hands;  what happens if the cell gets smaller?
now we have a new question on our hands;  what happens if the cell gets smaller?

Now you've probably heard of the term Atrophy  but this is easily one of the most misunderstood  
Now you've probably heard of the term Atrophy  but this is easily one of the most misunderstood  

terms in all of biology. Atrophy has nothing  to do with cellular death, instead it means  
terms in all of biology. Atrophy has nothing  to do with cellular death, instead it means  

that a cell is getting smaller. So, if a cell  undergoes atrophy, let's say from inactivity,  
that a cell is getting smaller. So, if a cell  undergoes atrophy, let's say from inactivity,  

there's no need for that extra nucleus. So, what  will happen is a process known as Apoptosis which  
there's no need for that extra nucleus. So, what  will happen is a process known as Apoptosis which  

is a form of programmed cellular death. So  that extra nucleus and the DNA inside of it  
is a form of programmed cellular death. So  that extra nucleus and the DNA inside of it  

will fragment, the MRNA will decay and that is  the end of the line for that particular nucleus.
will fragment, the MRNA will decay and that is  the end of the line for that particular nucleus.

For decades, many biologists assumed what's known  as The Myonuclear Domain Hypothesis. It's wordy,  
For decades, many biologists assumed what's known  as The Myonuclear Domain Hypothesis. It's wordy,  

I know but the idea is actually very simple.  Again, we're going to pretend that this is  
I know but the idea is actually very simple.  Again, we're going to pretend that this is  

a skeletal muscle cell. So, if it were to  become hypertrophic, a satellite cell just  
a skeletal muscle cell. So, if it were to  become hypertrophic, a satellite cell just  

on the outside of it would fuse and contribute its  nucleus then if that same cell becomes atrophic,  
on the outside of it would fuse and contribute its  nucleus then if that same cell becomes atrophic,  

the nucleus dies. It fragments and everything  we just discussed and what you're then left  
the nucleus dies. It fragments and everything  we just discussed and what you're then left  

with is the proper nucleus to cellular  volume ratio. Makes a ton of sense,  
with is the proper nucleus to cellular  volume ratio. Makes a ton of sense,  

problem is not every biologist agrees with it.
problem is not every biologist agrees with it.

How is it that one of these nuclei suddenly  becomes so compromised that its DNA fragments  
How is it that one of these nuclei suddenly  becomes so compromised that its DNA fragments  

and it goes into a downward death spiral but its  neighboring nuclei are more or less okay? It's  
and it goes into a downward death spiral but its  neighboring nuclei are more or less okay? It's  

a pickle for sure and then on top of this, when  you're looking at this through optical equipment,  
a pickle for sure and then on top of this, when  you're looking at this through optical equipment,  

it's difficult to see or know if the nucleus is  inside of the skeletal muscle cell or outside  
it's difficult to see or know if the nucleus is  inside of the skeletal muscle cell or outside  

of it - maybe like a satellite cell or a white  blood cell, a fibroblast. It's pretty challenging.
of it - maybe like a satellite cell or a white  blood cell, a fibroblast. It's pretty challenging.

It's entirely possible that the other  cells, the satellite cells, fibroblasts,  
It's entirely possible that the other  cells, the satellite cells, fibroblasts,  

white blood cells, those are the ones that  are actually experiencing apoptosis during  
white blood cells, those are the ones that  are actually experiencing apoptosis during  

muscle atrophy which would explain the measurable  markers of apoptosis that scientists are finding.
muscle atrophy which would explain the measurable  markers of apoptosis that scientists are finding.

Well, scientists studying of all things a  Tobacco Hawkmoth may have finally found the  
Well, scientists studying of all things a  Tobacco Hawkmoth may have finally found the  

answer. You see, during the moth's normal [?] to  adult development, something interesting happens  
answer. You see, during the moth's normal [?] to  adult development, something interesting happens  

on day 15. Its belly muscles undergo atrophy  losing 40% of its total mass which is crazy.
on day 15. Its belly muscles undergo atrophy  losing 40% of its total mass which is crazy.

If that happened to you, you would not be  doing well. Here's the thing - the moth's  
If that happened to you, you would not be  doing well. Here's the thing - the moth's  

muscles don't have the same satellite cells,  fibroblasts, white blood cells that mammals  
muscles don't have the same satellite cells,  fibroblasts, white blood cells that mammals  

do meaning that the nuclei that scientists  are observing are coming only from skeletal  
do meaning that the nuclei that scientists  are observing are coming only from skeletal  

muscle tissue and when the scientists  count the nuclei, they stay the exact  
muscle tissue and when the scientists  count the nuclei, they stay the exact  

same as they were when the muscles were  larger meaning there's no loss of nuclei.
same as they were when the muscles were  larger meaning there's no loss of nuclei.

Ask yourself this - what's the advantage  to the cell for accumulating new nuclei  
Ask yourself this - what's the advantage  to the cell for accumulating new nuclei  

and then destroying them shortly after? I mean,  
and then destroying them shortly after? I mean,  

environmental circumstances can shift very  quickly for humans going from hypertrophy  
environmental circumstances can shift very  quickly for humans going from hypertrophy  

to atrophy hypertrophy to atrophy. I mean, just  think about the lifestyle of a hunter-gatherer.
to atrophy hypertrophy to atrophy. I mean, just  think about the lifestyle of a hunter-gatherer.

Think about it like this - why is it that  it's easier to regain muscle mass than build  
Think about it like this - why is it that  it's easier to regain muscle mass than build  

it initially? Like let's say you put the work in  at the gym, right? You lift some weights, you're  
it initially? Like let's say you put the work in  at the gym, right? You lift some weights, you're  

building muscle mass through hypertrophy and then  bam, you break your arm playing rugby. Obviously,  
building muscle mass through hypertrophy and then  bam, you break your arm playing rugby. Obviously,  

you're gonna lose the gains in that arm because  you're going to spend the next couple months in a  
you're gonna lose the gains in that arm because  you're going to spend the next couple months in a  

cast and inactivity is a huge driver for atrophy  yet as any experienced gym goer can tell you,  
cast and inactivity is a huge driver for atrophy  yet as any experienced gym goer can tell you,  

it is definitely easier to regain what you  lost than build it in the first place and  
it is definitely easier to regain what you  lost than build it in the first place and  

one of the main reasons that's likely  true is the retention of myonuclei.
one of the main reasons that's likely  true is the retention of myonuclei.

I mean, think about it - all the cellular  adaptations or hypertrophy are already in place  
I mean, think about it - all the cellular  adaptations or hypertrophy are already in place  

except a recent paper published by James Bagley,  Kevin Murach and Andy Galpin suggests that the  
except a recent paper published by James Bagley,  Kevin Murach and Andy Galpin suggests that the  

myonuclei are only retained for a short period of  time. However, despite that, the muscles are still  
myonuclei are only retained for a short period of  time. However, despite that, the muscles are still  

able to bounce back easier in the long term and  it's possible this is due to epigenetic factors.
able to bounce back easier in the long term and  it's possible this is due to epigenetic factors.

Epigenetics is one of the most exciting areas of  research in biology and for good reason. You see,  
Epigenetics is one of the most exciting areas of  research in biology and for good reason. You see,  

DNA doesn't change much and that's actually a very  good thing. However, we don't actively use every  
DNA doesn't change much and that's actually a very  good thing. However, we don't actively use every  

gene in our genome. Instead, there are protein  markers on the outside of the genes that act  
gene in our genome. Instead, there are protein  markers on the outside of the genes that act  

as an on off switch and the interesting part is  they are heavily influenced by our environment.
as an on off switch and the interesting part is  they are heavily influenced by our environment.

When you do resistance training, you're telling  your muscles that there's an actual environmental  
When you do resistance training, you're telling  your muscles that there's an actual environmental  

need to be stronger and larger. This activates  and deactivates epigenetic switches in your genome  
need to be stronger and larger. This activates  and deactivates epigenetic switches in your genome  

making it easier for nuclei to regulate protein  synthesis as well as various other factors that  
making it easier for nuclei to regulate protein  synthesis as well as various other factors that  

contribute to muscle hypertrophy. This is  the muscular component of muscle memory.
contribute to muscle hypertrophy. This is  the muscular component of muscle memory.

Look, your muscles don't have consciousness but  they're still able to retain information which  
Look, your muscles don't have consciousness but  they're still able to retain information which  

can make it easier to rebound in the event  of a loss of muscle mass. I want you to take  
can make it easier to rebound in the event  of a loss of muscle mass. I want you to take  

a moment and think about what this means for  musculoskeletal health as it relates to aging.
a moment and think about what this means for  musculoskeletal health as it relates to aging.

Now, Jonathan just did an entire  video about resistance training and  
Now, Jonathan just did an entire  video about resistance training and  

how it relates to longevity, so please be  sure to check that out but in a nutshell,  
how it relates to longevity, so please be  sure to check that out but in a nutshell,  

resistance training isn't about looking  good and getting stronger. I mean,  
resistance training isn't about looking  good and getting stronger. I mean,  

those are awesome side effects that are obvious  mostly plenty motivating for a lot of people  
those are awesome side effects that are obvious  mostly plenty motivating for a lot of people  

in the world but resistance training is really  about stimulating skeletal muscle so that it can  
in the world but resistance training is really  about stimulating skeletal muscle so that it can  

adapt to improve your quality of life and then  you want to maintain that as long as possible.  
adapt to improve your quality of life and then  you want to maintain that as long as possible.  

The stronger you are the less susceptible you are  to injury. I mean, it's not like you're - it's  
The stronger you are the less susceptible you are  to injury. I mean, it's not like you're - it's  

impossible to get injured but you're less  susceptible and that should be enough for people.
impossible to get injured but you're less  susceptible and that should be enough for people.

It's not about looking good  and getting stronger - again,  
It's not about looking good  and getting stronger - again,  

that's awesome but what you really should be  doing when it comes to resistance training is  
that's awesome but what you really should be  doing when it comes to resistance training is  

focusing on the quality of life improvements and  what that's going to mean for you going forward.
focusing on the quality of life improvements and  what that's going to mean for you going forward.

Thanks for watching everybody. Geoffrey and I  really appreciate you hanging out with us. Now,  
Thanks for watching everybody. Geoffrey and I  really appreciate you hanging out with us. Now,  

all the resources used to make this video  are linked in the description below including  
all the resources used to make this video  are linked in the description below including  

an incredible paper from Lawrence Schwartz  that this video was heavily inspired from.
an incredible paper from Lawrence Schwartz  that this video was heavily inspired from.

Be sure to click the link in the description  below to start your Athletic Greens Journey  
Be sure to click the link in the description  below to start your Athletic Greens Journey  

today and also be sure to check out the link in  the description below to our sister company Ava  
today and also be sure to check out the link in  the description below to our sister company Ava  

that makes anatomical art. I mean, come on, you  can decorate your house, your office, your car -  
that makes anatomical art. I mean, come on, you  can decorate your house, your office, your car -  

probably not your car. That's probably not too  safe but all the other places are completely fine.
probably not your car. That's probably not too  safe but all the other places are completely fine.

As always, be sure to like, comment,  subscribe if you feel so inclined  
As always, be sure to like, comment,  subscribe if you feel so inclined  

and we'll see in the next video.
and we'll see in the next video.