How the Body Builds Incredible Strength Without Getting Bigger

Summary

This video explains the physiological adaptations that lead to strength improvements, both with and without muscle growth. It delves into the neural pathways, from brain to muscles, highlighting motor unit recruitment and synchronization as key factors in increasing strength. The video also covers the mechanics of muscle contraction, from neuron signals to protein interactions inside muscle fibers, and discusses training protocols like compound movements and high-intensity sets. Finally, it touches on nervous system adaptations, rest, recovery, and progression in strength training.

Takeaways

• 💪 Humans can improve strength through resistance training, which doesn't always result in increased muscle size.
• 🏋️‍♂️ Athletes may seek to maximize strength without gaining weight to improve their strength-to-body weight ratio, known as relative strength.
• 🧠 Strength improvements begin in the brain's motor cortex and involve a complex pathway through nerves to muscles.
• 🤖 The nervous system can improve strength by recruiting more motor units and synchronizing them more efficiently.
• 🔗 The neuromuscular junction's efficiency in releasing and recycling acetylcholine can lead to increased strength.
• 🏋️‍♀️ Muscle fibers contract through the interaction of proteins like myosin and actin, which can be enhanced for greater strength.
• 🚀 Strength can be improved without muscle hypertrophy by increasing the contractility of existing muscle fibers.
• 🏋️‍♂️ Compound exercises that engage multiple joints are recommended for stimulating strength adaptations.
• ⏱ High-intensity training with heavy loads and short rest periods can enhance strength gains.
• 🔁 Progressive overload and periodic deload weeks are important for continuous strength improvement.

Q & A

What are the two primary ways humans can improve their strength?

Humans can improve their strength by getting bigger, which often involves muscular hypertrophy, or by getting stronger without significant increases in muscular size through specific training protocols.

Why might an athlete want to increase their strength without gaining weight?

Athletes might want to increase their strength without gaining weight to improve their strength-to-body weight ratio, which is important for activities like vertical jumps or sports where they have to be in certain weight classes.

How does the nervous system contribute to strength improvements without muscle hypertrophy?

The nervous system can improve strength by becoming more efficient at recruiting motor units simultaneously and increasing the synchronization of motor units, allowing for more force generation without muscle hypertrophy.

What is the role of the motor cortex in muscle contraction?

The motor cortex in the brain initiates muscle contraction by sending signals through upper and lower motor neurons to the specific muscle fibers that need to contract.

What is a motor unit and how does it relate to strength?

A motor unit consists of a motor neuron and the muscle fibers it controls. The force exerted by a muscle during a contraction depends on the number of motor units recruited, which can increase strength without muscle hypertrophy.

What happens at the neuromuscular junction and how can it affect strength?

At the neuromuscular junction, a lower motor neuron releases acetylcholine, which binds to receptors on the muscle fiber, causing it to contract. Strength can be improved by increasing the efficiency of acetylcholine release and reuptake at this junction.

How do the proteins myosin and actin contribute to muscle contraction?

Myosin and actin are proteins within muscle fibers that interact to cause contraction. Myosin binds to actin, forming cross-bridges and pulling the actin filaments, leading to muscle contraction.

What physiological adaptations can occur within muscle fibers to increase strength?

Physiological adaptations within muscle fibers that increase strength include increasing the number of contractile proteins, improving the efficiency of calcium release and recycling, and strengthening the bond between myosin and actin.

What are some training protocols recommended for improving strength adaptations?

Recommended training protocols for improving strength adaptations include performing compound movements with high intensity and quality, using a rep and set scheme of 3 to 5 sets with 2 to 5 repetitions, and ensuring adequate rest periods between sets.

How often should one perform strength training sessions and why?

One should perform strength training sessions with adequate rest between them, typically 48 to 72 hours or more, depending on individual recovery capabilities, to allow for optimal recovery and adaptation.

What is the significance of the sarcoplasmic reticulum in muscle contraction?

The sarcoplasmic reticulum is significant in muscle contraction because it releases calcium in response to an action potential, which then binds to the troponin-tropomyosin complex, allowing myosin to bind with actin and initiate contraction.

Outlines

00:00

💪 Understanding Strength Gains and Training

This paragraph introduces the concept of strength improvement through exercise, particularly resistance training. It discusses the common belief that bigger muscles equate to greater strength, but also highlights that significant strength gains can occur without noticeable muscle size increases. The video promises to explore the different ways the body adapts to strength training, focusing on the distinction between getting bigger and getting stronger without size gains. It also mentions the importance of relative strength in certain sports and the role of the nervous system in muscle contraction and strength adaptation.

05:02

🏋️‍♂️ Neural Adaptations for Enhanced Strength

The second paragraph delves into the neurological aspects of strength training, explaining how the brain's motor cortex initiates muscle contractions through a series of neural pathways involving upper and lower motor neurons. It discusses the concept of motor unit recruitment, where the nervous system becomes more efficient at activating muscle fibers, leading to increased strength without muscle hypertrophy. The paragraph also introduces the idea of improved synchronization between motor units as a key adaptation to strength training, allowing for more forceful muscle contractions.

10:02

🧠 Neuromuscular Junction and Muscle Contraction

This paragraph focuses on the neuromuscular junction, the synaptic connection between motor neurons and muscle fibers, and its role in strength adaptation. It explains the process of acetylcholine release and its effect on muscle fiber contraction. The video also discusses how physiological adaptations at the neuromuscular junction, such as increased efficiency in acetylcholine release and reuptake, can lead to improved strength. The paragraph transitions into an exploration of the internal structure of muscle fibers, setting the stage for understanding further physiological adaptations.

15:03

🏋️‍♀️ Training Protocols for Strength Improvement

The final paragraph discusses specific training protocols aimed at improving strength. It emphasizes the importance of compound movements and high-intensity, low-repetition sets for stimulating strength adaptations. The video suggests that attempting to move weights quickly, even under heavy loads, can recruit more motor units and enhance nervous system adaptations. It also covers the importance of adequate rest periods and recovery time between sessions, as well as the concept of progressive overload and deload weeks for continuous strength gains. The paragraph concludes with a reminder that while it's possible to increase strength without significant muscle growth, eventually, muscle hypertrophy will be necessary for further strength improvements.

Keywords

💡Resistance Training

Resistance training refers to physical exercises designed to improve muscle strength by making muscles work against an external resistance. The video explains how resistance training leads to strength improvements through neural and muscular adaptations, and is a key method for increasing both muscle size and strength.

💡Muscular Hypertrophy

Muscular hypertrophy is the increase in muscle size due to the growth of muscle fibers. In the video, it is discussed that hypertrophy often accompanies strength gains, but the video emphasizes that significant strength can be achieved without noticeable increases in muscle size, which is beneficial for athletes in certain sports or weight classes.

💡Motor Unit

A motor unit consists of a motor neuron and the muscle fibers it controls. The video highlights how motor units play a crucial role in generating force during muscle contractions. More motor units are recruited as the demand for force increases, and strength training helps improve motor unit recruitment and synchronization for greater efficiency.

💡Neuromuscular Junction

The neuromuscular junction is the synapse where a motor neuron communicates with a muscle fiber, causing muscle contraction. The video describes how strength adaptations occur here, with training improving the efficiency of neurotransmitter release and reuptake, contributing to strength gains without muscle growth.

💡Action Potential

An action potential is an electrical signal that triggers muscle contraction. In the video, it is explained that action potentials travel from the brain, down the spinal cord, to motor neurons, eventually causing muscle contraction. The efficiency of this process can be enhanced through strength training, allowing muscles to contract more forcefully.

💡Myosin and Actin

Myosin and actin are the proteins responsible for muscle contraction. Myosin binds to actin, creating the 'ratcheting' motion that causes muscle fibers to contract. The video discusses how increasing the number or improving the efficiency of these proteins can lead to greater strength without necessarily increasing muscle size.

💡Motor Cortex

The motor cortex is the part of the brain responsible for generating the neural signals that initiate voluntary muscle contractions. The video explains that strength improvements can originate from the brain, where the motor cortex becomes more efficient at sending signals to recruit more motor units during strength training.

💡Fast Twitch Muscle Fibers

Fast twitch muscle fibers are responsible for quick, forceful muscle contractions but fatigue more easily than slow-twitch fibers. The video touches on how strength training can cause some slow-twitch fibers to convert to fast-twitch, which improves the body's ability to generate force without gaining muscle mass.

💡Strength-to-Body-Weight Ratio

Strength-to-body-weight ratio refers to how strong an individual is relative to their body weight. The video emphasizes the importance of this ratio for athletes who need to maximize strength without increasing body weight, such as those in weight-class sports or those aiming to improve relative strength-based movements like jumping.

💡Sarcoplasmic Reticulum

The sarcoplasmic reticulum is a structure within muscle fibers that stores and releases calcium, which is critical for muscle contraction. The video explains how, during strength training, the efficiency of calcium release and reuptake can improve, leading to stronger muscle contractions and increased strength.

Highlights

Humans can improve their strength through exercise, especially resistance training.

Strength can increase without significant muscle size increase or hypertrophy.

Relative strength, the ratio of strength to body weight, is crucial for athletes in weight-restricted sports.

Muscular strength is measured by the force muscles can produce, often represented by one rep max.

The brain's motor cortex initiates muscle contraction signals that travel through the nervous system.

Motor unit recruitment and rate of neural signals affect the force exerted by muscles.

Strength training can improve neural efficiency in motor unit recruitment and synchronization.

The neuromuscular junction's efficiency in releasing acetylcholine can enhance strength.

Muscle fibers contract through the interaction of proteins myosin, actin, and the regulatory complex TTC.

Strength can be improved by increasing the contractility of muscle fibers without increasing their size.

Some strength improvements come from slow twitch muscle fibers converting to fast twitch fibers.

Compound movements that involve multiple joints are effective for strength training.

High-intensity, low-repetition sets with heavy loads are recommended for strength gains.

Moving the weight as quickly as possible during lifts can recruit more motor units.

Adequate rest periods of 2 to 5 minutes between sets are necessary for high-intensity training.

Progression in strength training involves increasing intensity and volume gradually.

A deload week every 5 to 6 weeks can help avoid overtraining and promote recovery.

After reaching a strength plateau, muscle size increases may be necessary to continue getting stronger.

Transcripts

humans have an incredible capacity to

improve their strength with certain

types of exercise most often through

resistance training but what actually

happens inside the body when you get

stronger and what's the best training

protocol to accomplish this often you

hear that if you want to get stronger

you have to get bigger and yes it is

true that often a bigger muscle is a

stronger muscle however you can actually

get significant strength improvements

without much or any increases in

muscular size or muscular hypertrophy so

today we're going to explain the

different strength adaptations that

occur with getting stronger by getting

bigger versus getting stronger without

putting on much size and we're going to

do this by showing you some awesome

relevant Anatomy by taking you from the

brain through the nerves and into the

muscles and of course talk about some of

the training protocols to improve your

strength so let's do

this so let me first start by asking why

in the world would anyone not not want

to get bigger and stronger at the same

time well there are plenty of athletes

where they may want to be as strong as

possible without putting on much weight

or in other words their strength to body

weight ratio is important this is also

known as relative strength which is a

measure of how strong an individual is

in say like a particular lift or

movement compared to their body weight

like having a high relative strength

would be very beneficial for say

something like a vertical jump also

there are sports where people have to be

in certain weight classes so they may

want to maximize their strength at that

weight but what is muscular strength

muscular strength is about how much

force your muscles can produce and we

most often represent this by someone's

one rep max the greatest amount of

weight you could lift one time and

obviously today we're going to talk

about how you can improve that now

earlier I mentioned that we were going

to take you from the brain through the

nerves and into the muscles and what we

will see is that we can get adaptations

in multiple places along this chain and

what when I say into the muscles we're

going to go deep inside of the muscles

to show you how the muscle contracts as

well as certain intracellular

adaptations that improve without

increasing the size of the muscle fiber

it's ridiculously awesome so let's get

into the brain when you decide to

contract a muscle this starts all the

way up in the brain in the motor cortex

which is this fold or what we refer to

as a gyrus on the posterior aspect of

the frontal lobe the signal will move

from the motor cortex

through a neuron called an upper motor

neuron which travels down the spinal

cord and this upper motor neuron will

eventually synapse with a lower motor

neuron at a specific segment of the

spinal cord depending on the muscle

we're sending the signal to for example

if this signal is going to the biceps

brachi this synapse between the upper

and lower motor neuron would occur at C5

or C6 spinal cord levels if the signal

were going to a lower muscle like the

quads the synapse would occur at the L2

L3 or L4 spinal levels but after the

synapse occurs the axon of the lower

motor neuron and therefore the

continuation of the signal will travel

through a spinal nerve until it reaches

its Target muscle where it will then

synapse with specific muscle fibers that

make up that Target muscle and this

causes those muscle fibers to contract

now let's pause right here for a second

and connect some more dots that lower

motor neuron that connected to a certain

amount of muscle fibers within the whole

muscle is called a motor unit or the

textbook definition that I will often

give my students is a motor unit is the

motor neuron and the muscle fibers it

controls but with our example we only

activated one lower motor neuron and

therefore one motor unit which means we

only activated a small amount of the

total number of muscle fibers within

that whole muscle and so this is only

going to generate a minimal amount of

force and so this is how motor unit

recruitment works if I lift something

light I need fewer muscle fibers to do

that so I only need to recruit a few

motor units but if I want to lift

something heavy I need more muscle

fibers to be activated within the muscle

and so then I would start by activating

more upper motor neurons in that motor

cortex which would then in turn activate

more lower motor neurons that form the

motor units with those muscle fibers and

I would generate more force or lift

something heavier so hopefully you are

seeing that the force exerted by a

muscle during a contraction depends on

the number of motor units recruited not

only does it depend on the number of

motor units recruited but it also

depends on the rate or how fast those

signals can be sent to the muscle a

faster signal generally means more force

and this is where we see one of our

first improvements in strength without

the muscles undergoing hypertrophy

because with specific types of training

which we'll get into later your nervous

system this pathway that we just

discussed gets more efficient at

recruiting motor units it does this by

getting better with recruiting more

motor units simultaneously on demand as

well as by increased synchronization of

those motor units when you first start

strength training your muscle fibers

might not fire in perfect sequence or in

a perfectly coordinated manner but as

you continue to train your nervous

system gets better at synchronizing

those motor units working together more

efficiently and all this results in more

Force gener ated by the muscle without

getting any bigger and real quick I want

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today's video and now back to strength

so now let's move on to the next

physiological adaptation that can result

in improved strength and in order to do

this we're going to zoom into the

synaptic connection between the end of

that lower motor neuron and the cell

membrane of a muscle fiber and the

synaptic connection is referred to as

the neuromuscular Junction and as you

can see they're not technically

connected there's actually a space

between the end of that lower motor

neuron and the cell membrane of the

muscle fiber and that space is referred

to as the synaptic Clift and as an FYI

the cell membrane of a muscle fiber is

referred to as the sarcolemma but if we

look at the inside of the end of that

lower motor neuron we can see these

bag-like structures called synaptic

vesicles and Within These synaptic

vesicles there's a neurotransmitter

called acetylcholine and when that

signal gets sent down that lower motor

neuron those synaptic vesicles release

the acetylcholine into that synaptic

Clift and then those acetylcholine

molecules will bind to the acetylcholine

receptors embedded in the membrane of

that muscle fiber and this will then

cause ion channels to open up and so

sodium will rush into the muscle fiber

and this creates an action potential and

eventually leads to the muscle fiber

Contracting now we'll get into a little

bit more of that in just a second but

right here at the neuromuscular Junction

we can get physiological adaptations

that can result in improved strength

that lower motor neuron can get more

efficient at releasing the acetylcholine

and within that synaptic Clift we have

certain enzymes that are in charge of

breaking down the acetylcholine so that

it can be recycled and put back into

that lower motor neuron this process of

reuptake and this whole process can also

get more efficient so just having

changes at the neuromuscular Junction

can also result in improved strength so

now let's go inside the muscle fiber to

learn how a muscle fiber contracts and

of course this will help us to

understand some other physiological

adaptations that result in strength and

if we go to the inside of a muscle fiber

we'll see that it's made up of multiple

multiple contractile protein subunits

called sarir and sarir are stacked end

to end to end to end in sequence kind of

creating this string of sarir and a

string of sarom miror is referred to as

a myof fibral now if we just focus in on

one sarir we can get a great

understanding of how a muscle fiber

actually contracts and we're going to

focus on three proteins that make up the

sarir there's more than three but these

three are the most important for our

story the first one is Mein and if you

look at this picture you can see one

mein molecule or one iin protein and to

me it looks like two golf clubs Twisted

together if you can kind of see that

analogy or stretch this analogy with me

you can see the masin heads would be

where you'd actually hit the golf ball

where the mein Tails would be the actual

shafts of the golf club and they're kind

of Twisted together now all the mein

molecules bundled together create a

thick filament within the sarcom so

multiple mein molecules bundled together

equals thick filament in SAR but then

the other protein we want to take a look

at is act

one actin molecule or actin protein is

one like circular ball that you're

seeing in this picture and you can see

that there's multiple actin molecules

strung together it almost looks like two

strings twisted and all those actin

molecules Twisted together on that

string creates the thin filament so mein

bundled together makes a thick filament

all the actin molecules strung together

equals the thin filament now you'll

notice that thin filament also has

another protein associated with it this

protein wrapping around the thin

filament is called TTC or troponin

tropomyosin complex and what's really

interesting about this whole interaction

between these three proteins is I often

will tell my students masin is in love

with actin mein wants nothing more than

to bind to actin and cuddle or what

we'll refer to as ratcheting a little

bit later on but TTC you could kind of

think of them as the protective parents

of actin they don't want mein cuddling

and ratcheting with actin they're trying

to protect it so when you see TTC

covering up The Binding sides of actin

that's when a sarcomere is in a resting

state but for us to understand how a

muscle fiber contracts we need to go

back to the neuromuscular Junction where

we learned that that lower motor neuron

released acetylcholine and the

acetylcholine would bind to the

acetylcholine receptors in the membrane

of the muscle fiber and when this

occurred it caused ion channels within

the membrane of the muscle fiber to open

up and sodium would rush into the muscle

fiber creating an action potential now

if you don't feel like we've gone into

the weeds enough we could go further

into the weeds when we talk about the

action potential that occurs with muscle

fibers but we're going to save that for

another video today what we need to know

is that when this action potential

occurs it affects a specific structure

within the muscle fiber called the

sarcoplasmic reticulum and this

sarcoplasmic reticulum is in close

proximity and wraps around these C cir

and it contains Calcium so when the

action potential occurs it causes the

sarop plasma creticum to release the

calcium and then calcium binds to TTC

and when calcium binds to TTC it causes

the TTC to change its shape just enough

to slightly move out of the way and

expose those binding sites on actin and

what will myosin do as soon as those

binding sites are Exposed on actin

mein's going to bind and Ratchet or what

we kind of referred to as cuddling

earlier but you can see that ratcheting

or some book books will refer to it as

the power stroke that's going to pull

and start to shorten the ccle miror and

what's interesting about this bond

between masas and an actin is that it

requires a high energy molecule ATP to

actually break that Bond so we burn an

ATP the myosin will release and actually

reset the head but then bind to a

further down acting molecule and Ratchet

again use another at P reset bind

further down and Ratchet again and you

can see that would shorten by ratcheting

and ratcheting and ratcheting the

overall sarir and therefore shorten the

overall muscle fiber and what's crazy to

think about is there are multiple mein

heads multiple actin molecules doing

this within each individual sarcomere

and it's just happening ridiculously

fast like every time I'm moving a muscle

these sarir are shortening and I just

can't keep up with it but this whole

idea of what's happening with the muscle

contraction and now that that we

understand it a little bit more fully

this can help us to learn some more

physiological adaptations that occur

with improvements and strength now one

way to get stronger with this whole

process that we just learned is that you

could increase the number of contractile

proteins within the muscle fiber

increase the amount of meas and an actin

and you're going to be able to generate

more Force however if you make more meas

and an actin this is going to take up

space and therefore increase the overall

size of the muscle and again this often

happens with people who are doing

certain types of resistance training

they get muscular hypertrophy going hand

inand with increases in muscular

strength however it has been shown with

certain types of strength training that

you can have improved contractility of

the sarir and therefore generate more

Force independent of increases in

muscular size or in other words the

sarir and the contractile proteins that

you do have start to contract more

forcefully without making more of them

and there are a few reasons for this one

is the speed and efficiency at which the

calcium is released and recycled with

the sarop plasmic reticulum increases

also there's evidence that suggests the

bond between mein and actin also gets

stronger which of course I just think is

great with my love story analogy because

the more time these two spend together

connecting and pulling on each other the

stronger that bond gets and they cuddle

and Ratchet even harder producing more

force and strength for the muscle now we

do also need to address that some

strength improvements can come from some

of the slow twitch muscle fibers

converting to more of a fast twitch

fiber in general we say that slow twitch

fibers are great at resisting fatigue so

they are great for endurance activities

however they don't generate as much

force whereas the fast twitch fibers not

great at resisting fatigue but they

contract with more velocity and force so

some conversion of the slow twitch to

fast twitch fibers can also explain

improvements in one's overall strength

so what are some of the important

training protocols that are more

specific cific to improving some of

these strength adaptations first you

typically want to pick compound

movements these are movements that

involve multiple joints such as the

squat deadlift bench press shoulder

press rows pull-ups Etc and to stimulate

these strength adaptations the rep and

set scheme is also going to need to be

of a higher quality and higher intensity

so this will usually consist of 3 to

five sets per exercise with a load or a

weight that you could only perform about

two to five repetitions with it is also

helpful to try to move the load as

quickly as possible without of course

sacrificing form control or safety now

the reality is that with these heavy

loads you aren't going to move the

weight that fast but it has been shown

that if you consciously try to move the

weight as fast as possible even though

it isn't going to look like it's moving

much faster this has been shown to

recruit more motor units and stimulate

these nervous system strength

adaptations that we've been discussing

so far so imagine imagine a controlled

lowering of the squat and you attempting

to stand up or press the weight up as

quickly as possible again with

maintaining form control and safety and

because we are going for higher

intensity and higher quality rest is

usually at least 2 to 3 minutes between

sets and you could even push that to 3

to 5 minutes if you have the extra time

as this would just enhance the quality

of each high-intensity set but you

aren't going to sacrifice that much as

far as long-term adaptations are

concerned if you have limited time and

you can only rest for that 2 to 3

minutes one other thing to keep in mind

is that due to this type of training

being of a higher intensity and

neurologically demanding you usually

need a few days to recover before doing

another session that uses the same

muscle groups and movement patterns that

will vary a little bit from person to

person based on recovery capabilities so

some may only need 48 hours to recover

While others may need 72 hours or more

now as far as progression A good rule of

thumb would be to increase the intensity

by about 3 to 5% per week which usually

comes in the form of adding more weight

as well as a 3 to 5% increase in the

volume that volume could come in the

form of additional sets or maybe even

squeezing one or two extra workouts in

per month you would also want to

consider a D Lo week every 5 to six

weeks or so where you decrease the

intensity for that week that could come

with fewer sets Andor slightly lighter

loads now as cool as it is to be able to

increase strength without changing

muscular size much it is important to

note that eventually you'll get to a

point where you maximize the strength

with the muscular size that you have

which means you will get to the point

where you will need to get some

increases in muscular size in order to

continue to get stronger and this is

when people at the end of their

strength-based workouts could throw in

some sets and exercises that are more

dedicated to stimulating hypertrophy

generally this includes higher reps and

more volume which we'll definitely get

more into with part two to this video

and as always thanks for watching

everyone hopefully you'll learn some new

and interesting information about

strength adaptations if you want to

learn more about other adaptations that

can occur from exercise we'll link some

pretty cool videos here and like And

subscribe if you feel the need and I'll

see some of you down in the comments