Your Muscles Might Be Strong Enough. Your Nervous System Just Won't Let You Use Them.

Okay this is something I didn't properly understand about the gym for a long time.

I assumed strength was basically:

bigger muscle = stronger person.

Makes sense.

If I grow my biceps, I should be able to curl more.

If my legs get bigger, I should squat more.

And obviously muscle size DOES matter.

But then there's something weird.

When beginners start lifting, they can get significantly stronger before they've built enough new muscle to explain all of that strength.

So...

Where did the strength come from?

Did the muscle secretly grow overnight?

No.

Part of the answer is that your nervous system simply got better at using the muscle you already had.

And this sent me down a really interesting rabbit hole.

Because your muscles aren't just sitting there waiting for you to consciously turn them to 100%.

Your brain and nervous system control how they're recruited.

Which means strength isn't only about how much muscle you have.

It's also about how effectively your nervous system can make that muscle work.

Your muscles don't move themselves

Let's start from the beginning.

Say I want to curl a dumbbell.

My brain doesn't somehow directly pull my forearm upward.

It generates neural activity.

Signals travel down through my spinal cord.

Then through motor neurons.

Those neurons communicate with muscle fibers.

The fibers contract.

My arm moves.

So every single rep at the gym is basically:

brain → spinal cord → nerves → muscle → movement

Your muscles are the engine.

Your nervous system is controlling the engine.

And having a massive engine doesn't automatically mean you're good at putting all of its power onto the road.

Meet the motor unit

This is where strength starts getting interesting.

A motor neuron connects to a group of muscle fibers.

That neuron + all the muscle fibers it controls is called a motor unit.

When that neuron fires, those muscle fibers contract.

But your body doesn't activate every motor unit in a muscle every time you move.

That would be ridiculous.

Imagine picking up your phone and your biceps went:

MAXIMUM OUTPUT

and launched the phone through your ceiling.

Instead, your nervous system recruits motor units based on how much force you need.

Pick up a pen?

Very little.

Pick up a grocery bag?

More.

Try to deadlift something extremely heavy?

Okay boys everybody get in here.

Your brain can recruit more muscle when it needs more force

This is called motor-unit recruitment.

As force requirements increase, your nervous system recruits progressively more motor units.

And generally it follows something called the size principle.

Smaller, lower-threshold motor units get recruited first.

Then as more force is required, larger, higher-threshold motor units join.

So your muscle isn't really one giant thing switching between:

OFF

and

ON.

It's more like an army.

For easy tasks:

Send 50 soldiers.

Harder task:

Send 500.

Extremely heavy squat:

EVERYBODY GET THE FUCK OVER HERE.

😭

And recruitment isn't the only thing

Your nervous system can also change how frequently motor neurons fire.

This is called rate coding.

Basically, once a motor unit is recruited, the nervous system can increase its firing frequency.

Higher firing rates can produce greater force.

So your nervous system has multiple ways of controlling muscular output.

Recruit more motor units.

Make them fire faster.

Coordinate their activity.

Coordinate different muscles.

Reduce unnecessary opposing forces.

Suddenly "strength" becomes a lot more complicated than:

big muscle = strong.

This explains beginner strength gains

This is one of the coolest parts.

Suppose you've never trained seriously.

You start bench pressing.

Week 1:

40 kg feels horrible.

A few weeks later:

50 kg.

Then 55.

Your chest probably didn't suddenly become 40% larger.

Part of what happened is neurological.

Your nervous system became better at performing the movement.

Better motor-unit recruitment.

Better firing patterns.

Better coordination.

Better technique.

Better synchronization between the muscles involved.

Less wasted movement.

You basically upgraded the software controlling your existing hardware.

That's why strength can increase relatively quickly when you first start training even before dramatic hypertrophy becomes visible.

Your brain also has to coordinate multiple muscles

Take a bench press.

It's not just:

chest.exe

Your chest is involved.

Triceps.

Anterior delts.

Muscles stabilizing your shoulder.

Muscles controlling the bar.

Your nervous system has to coordinate all of these muscles at the right time.

When you're new to the movement, you're inefficient.

One muscle produces force.

Another isn't contributing enough.

The bar moves strangely.

You waste energy stabilizing it.

Maybe you're accidentally producing unnecessary tension somewhere else.

After hundreds of repetitions, your nervous system gets better.

The movement becomes smoother.

That's a skill.

Which is why strength training isn't purely building muscle.

You're also practicing a movement.

This is why someone smaller can sometimes be much stronger than you

We've all seen this.

Some dude doesn't look THAT big.

Then he casually lifts something ridiculous.

Meanwhile someone twice his size struggles with it.

Muscle size obviously matters.

But so do:

Technique.

Training history.

Tendon properties.

Limb proportions.

Motor-unit recruitment.

Neural adaptations.

Specificity.

Skill.

So looking muscular and being strong are related, but they're absolutely not identical.

Bodybuilders and powerlifters demonstrate this really well.

A bodybuilder is optimizing heavily for muscle growth.

A powerlifter is optimizing heavily for producing maximum force in specific movements.

There's overlap.

But they're not the same goal.

So are we secretly much stronger than we think?

Kind of.

But this is where the internet usually turns an interesting concept into nonsense.

You've probably heard stories like:

"Humans only use 30% of their strength because the brain limits us."

Or:

"Your muscles could lift a car but your brain stops you."

That's way too simplistic.

There isn't some universal limiter sitting in your brain saying:

strength = 30%

Healthy people performing maximal voluntary contractions can already recruit a very large proportion of available motor units in many muscles, especially if they're trained.

So no, you probably don't have some hidden 3x strength cheat code that your brain refuses to unlock.

Sorry.

Would've been cool.

But your nervous system DOES regulate output

This part is real.

Your nervous system isn't designed purely around:

produce maximum possible force.

Its job is to keep the organism functioning.

Your brain receives information from muscles, tendons, joints and other tissues.

It adjusts motor output based on the situation.

Fatigue matters.

Pain matters.

Injury matters.

Confidence matters.

Experience matters.

The state of your nervous system matters.

So the force you voluntarily produce isn't simply:

maximum mechanical capability of muscle fibers.

It's the result of a biological control system.

Your tendons are part of this too

There's another interesting piece of hardware called the Golgi tendon organ.

These sensory receptors sit around the muscle-tendon junction and detect tension.

You'll sometimes hear people say:

"The Golgi tendon organ stops you from using your full strength so you don't rip your muscles apart."

That's another oversimplification.

Their role is more complicated than being a simple emergency kill switch.

They provide the nervous system with information about muscle tension and participate in regulating force.

The important idea is:

Your muscles constantly communicate back to your nervous system.

This isn't a one-way system.

Brain:

CONTRACT.

Muscle/tendon sensors:

Here's what's happening.

Brain/spinal circuitry:

Okay, adjust.

It's a feedback loop.

Then there's adrenaline

This is where those crazy emergency-strength stories come from.

Someone gets trapped.

Someone they love is in danger.

Something catastrophic happens.

And suddenly they seem capable of producing an absurd amount of force.

You'll hear stories about people "lifting cars."

Some of these stories are exaggerated, and lifting one side of a vehicle is obviously not the same as deadlifting the entire car.

But extreme stress absolutely changes physiology.

Adrenaline rises.

Heart rate increases.

Blood flow changes.

Alertness shoots up.

Pain perception can change.

Your nervous system becomes highly activated.

The body basically goes:

THIS IS NOT A PRACTICE ROUND.

Under those conditions, a person may produce more force than they normally would voluntarily.

But again, there's no magical 1000% strength mode.

You haven't transformed into Hulk.

You're changing the operating state of the same neuromuscular system.

Pain itself is interesting here

Pain isn't simply:

damage detector.

It's an experience created by your nervous system based on sensory information, context, expectations and perceived threat.

That's why pain and physical damage aren't always perfectly correlated.

Sometimes relatively minor damage hurts enormously.

Sometimes people sustain serious injuries during emergencies and don't immediately notice them.

The nervous system is constantly deciding what information deserves your attention.

Which is honestly slightly terrifying.

Your experience of your body isn't raw reality.

It's your brain's interpretation of what's happening.

Fatigue isn't purely "muscles ran out of energy" either

This one surprised me.

When you're exhausted during a workout, some of the limitation is happening in the muscle itself.

Metabolites accumulate.

Energy availability changes.

Contractile performance decreases.

That's peripheral fatigue.

But there can also be central fatigue, involving changes in the nervous system's ability to drive the muscles.

So when your body says:

I'M DONE.

that's not necessarily one simple mechanism.

Your brain.

Spinal cord.

Motor neurons.

Muscles.

Energy systems.

Sensory feedback.

Motivation.

All of these things are interacting.

Fatigue is basically your entire system arguing about whether another rep is a good idea.

This explains why your mental state can affect performance

Ever have a gym session where everything feels heavy?

Same body.

Same muscles.

Same weights.

But somehow:

nah.

Then another day you walk in feeling incredible and weights move ridiculously easily.

Obviously sleep, nutrition and recovery matter.

But your nervous system matters too.

Arousal.

Focus.

Motivation.

Stress.

Familiarity with the movement.

All of these can affect performance.

This is also why powerlifters don't calmly approach a world-record deadlift like they're selecting vegetables at a supermarket.

They're trying to create a high-arousal state.

Music.

Shouting.

Smelling salts sometimes.

Psyching themselves up.

They're changing the state of the system controlling the muscles.

But more arousal isn't always better

Here's the funny part.

You might think:

Great.

I'll just become maximally hyped before every exercise.

Not necessarily.

Too little arousal?

Sluggish.

Too much?

Technique can fall apart.

You rush.

You lose precision.

Your heart is going insane.

For something requiring fine motor control, extreme arousal can actually make you worse.

Which connects back to why your hands shake when you're nervous.

Your nervous system is heavily activated.

Great if you need explosive movement.

Not great if you're trying to carefully thread a needle.

Strength is partly a skill

This completely changed how I think about lifting.

If I want to become good at bench pressing...

I should bench press.

Sounds stupidly obvious.

But it matters.

Your nervous system becomes specifically adapted to movements you repeatedly practice.

Technique improves.

Coordination improves.

You become comfortable producing high force in that movement.

That's why simply having enormous pecs doesn't automatically give you an elite bench press.

You still need to learn how to express that strength through the movement.

Strength is not just something you have.

It's something your nervous system learns how to express.

And this is why training heavy actually matters for strength

If your only goal is building muscle, you can grow using a fairly broad range of loads as long as training is sufficiently challenging.

But maximum strength is more specific.

You need experience handling heavy loads.

Your nervous system needs to become good at producing high force.

Your technique needs to work under heavy weight.

Your brain needs to stop treating 90% of your max like some completely unfamiliar emergency.

You basically teach your nervous system:

We've done this before.

So can we train the nervous system?

Yes.

We already do.

That's part of what strength training is.

Heavy resistance training isn't only changing your muscles.

It's changing the neural system controlling those muscles.

This is one reason athletes train explosively.

Sprinters.

Weightlifters.

Powerlifters.

Jumpers.

They're not simply trying to make muscles bigger.

They're training the entire neuromuscular system to produce force effectively and quickly.

This makes muscle memory even more interesting

Stop training for a while.

You get weaker.

Some muscle disappears.

Then you start again.

And often your strength returns MUCH faster than it took to build originally.

There are muscular reasons for this, including long-lasting adaptations within previously trained muscle.

But you're also relearning movements you've already practiced thousands of times.

Your nervous system isn't starting from zero.

It's more like reopening a project you haven't touched in six months.

At first:

what the fuck is going on here?

Then:

ohhh right.

And suddenly everything starts coming back.

The brain + muscle distinction is actually kind of fake

The more I learn about this, the more I realize we talk about the body in weird isolated pieces.

Muscles.

Brain.

Nerves.

Tendons.

Heart.

As if they're independent machines.

They're not.

When you lift something, you're using a system.

Your brain generates the intention.

Your nervous system organizes movement.

Motor neurons activate muscle fibers.

Muscles generate force.

Tendons transmit it.

Sensory receptors report what's happening.

Your nervous system adjusts.

Again.

Again.

Again.

All happening incredibly quickly without you consciously controlling any of it.

Meanwhile your conscious experience is just:

pick dumbbell up.

And that's the part I find insane

I can look at my hand right now and decide:

move index finger.

And it moves.

Instantly.

I don't think about which neurons to fire.

I don't choose motor units.

I don't calculate force.

I don't control individual muscle fibers.

I don't process sensory feedback.

Billions of biological processes just cooperate and somehow convert:

I want this finger to move

into:

finger moves.

We've been doing it since childhood, so it feels completely normal.

But it's actually ridiculous.

Your muscles aren't the whole story

So the title of this article is slightly clickbaity.

Your nervous system isn't secretly preventing you from becoming Superman.

You can't meditate hard enough and suddenly deadlift a car.

But the underlying idea is real:

The strength you can express isn't determined by muscle size alone.

It's muscle + nervous system + technique + coordination + training + biomechanics + fatigue + psychology + a bunch of other things happening together.

And when you start training, you're not just building bigger muscles.

You're teaching your brain how to use them.

Which means every time you walk into the gym and practice a movement, you're upgrading two things.

The hardware.

And the software.

And sometimes...

the software gets stronger before the hardware even looks different.