If You Skip Leg Day, Your Arms Won’t Grow As Much As They Could

Summary

The video script discusses the interconnectedness of muscle growth, emphasizing that skipping leg day can hinder arm growth due to systemic effects of resistance training. It explains that while the trained muscle receives the most benefits, there are also whole-body responses, including hormone changes and muscle protein synthesis. The speaker uses an amplifier and speaker analogy to clarify this concept, suggesting that working larger muscle groups like legs can indirectly enhance the growth of smaller muscle groups, such as arms. The script also touches on evolutionary reasons for these systemic effects, advocating for balanced training to prevent imbalances and maximize muscle development.

Takeaways

• 💪 Skipping leg day can limit overall muscle growth, including in the arms, due to systemic effects on muscle development.
• 📚 Historical observations from the 1970s support the idea that leg strength training can indirectly affect arm size.
• 🧬 Scientific studies show that working out one arm can reduce muscle atrophy in an incapacitated arm, indicating a systemic muscle-building effect.
• 🤔 The systemic effect is not just attributed to the central nervous system (CNS) but also involves other factors like isometric contractions for stabilization.
• 🔊 The 'amplifier and speaker' analogy is used to explain how training large muscle groups (like legs) can enhance the development of smaller muscle groups (like arms).
• 🌱 Evolutionary perspective suggests that the body avoids imbalances for survival, which could explain the systemic muscle-building effect.
• 🏋️‍♂️ Large muscle group training, such as leg exercises, has a more significant systemic effect on overall muscle growth compared to smaller muscle groups.
• 🚫 Skipping certain body parts during workouts not only stunts the development of the skipped area but also limits the muscle-building potential in other areas.
• 🏋️‍♀️ Female clients who avoid upper body exercises may also limit their potential for building a larger butt, emphasizing the interconnectedness of muscle groups.
• 🤲 The importance of engaging the CNS for maximal strength output is highlighted by the grip strength example, showing the mind-muscle connection.
• 🧘‍♂️ The difficulty of activating muscles maximally while maintaining relaxation illustrates the body's natural tendency to engage the CNS for strength tasks.

Q & A

What is the main claim made in the script about skipping leg day?

The main claim is that skipping leg day can limit the growth of your arms, as there is a systemic effect of resistance training that impacts muscle growth across the body, not just in the trained area.

How does the script explain the concept of systemic effects in muscle building?

The script explains that while the muscle directly trained receives the most muscle-building effects, there is also a systemic effect that influences muscle growth throughout the body. This is supported by studies showing that training one arm can prevent atrophy in an incapacitated arm.

What is the role of the central nervous system (CNS) in the systemic effects of training?

The script suggests that the CNS plays a significant role in the systemic effects of training. It is hypothesized that the CNS, through mechanisms like irradiation, helps to stabilize and contract muscles isometrically, contributing to the overall muscle-building effects.

How does the script relate the concept of an 'amplifier and speaker' analogy to muscle training?

The script uses the analogy of an amplifier and speaker to explain how training one muscle group (like the legs) can indirectly affect other muscle groups (like the arms). Just as a stronger amplifier enhances the performance of all connected speakers, training large muscle groups can have a systemic effect on the entire body.

What evolutionary perspective does the script offer regarding muscle imbalance?

The script suggests that from an evolutionary standpoint, the body seeks to avoid significant imbalances because they are disadvantageous for survival. The systemic muscle-building effect is seen as a mechanism to maintain balance and homeostasis in the body.

Why might someone experience increased upper body strength after focusing on leg training?

The script explains that focusing on leg training can lead to increased upper body strength due to the systemic effects of training. As the body works to maintain balance, it may enhance muscle growth and strength in other areas, even if they are not directly trained.

How does the script address the impact of training large muscle groups on overall muscle growth?

The script states that training large muscle groups like the legs has a more significant systemic effect on muscle growth than training smaller muscle groups. This is because working out large muscle groups involves more of the body, leading to a broader impact on muscle protein synthesis and hormone levels.

What is the script's stance on the effectiveness of free weights versus machines for muscle building?

The script implies that free weights are generally more effective for building muscle and strength than machines due to the additional stabilization and systemic effects they provide. Free weight exercises often engage more muscles and require more from the CNS, leading to a greater overall impact.

How does the script illustrate the concept of CNS activation with a grip strength example?

The script uses the example of grip strength to show how activating the CNS can increase strength. It suggests that squeezing while relaxed will yield less strength compared to squeezing while tensing the entire body, demonstrating the CNS's role in muscle activation.

What does the script suggest about the importance of training all body parts for optimal muscle development?

The script emphasizes that training all body parts is crucial for optimal muscle development, as skipping certain areas can limit the potential for growth in other areas due to the body's systemic response to training.

Outlines

00:00

💪 The Impact of Skipping Leg Day on Muscle Growth

This paragraph discusses the widespread belief in the fitness community that skipping leg day can hinder overall muscle growth, including in the arms. It references historical observations and scientific studies that suggest training larger muscle groups like the legs can have a systemic effect on muscle growth throughout the body. The explanation involves concepts like muscle atrophy prevention, the CNS (central nervous system) effect, and the body's evolutionary drive towards balance and homeostasis. The speaker uses an analogy of an amplifier and speakers to explain how training one muscle group can indirectly benefit others.

05:00

🏋️‍♂️ The Systemic Benefits of Free Weight Training

The second paragraph delves into the systemic benefits of free weight training, particularly for the legs, and how it can affect upper body strength as well. It emphasizes that most free weight exercises inherently involve the upper body to some degree, either in stabilizing or holding the weight. The paragraph also touches on the idea that free weights generally promote more muscle and strength growth than machines, possibly due to the increased demand on the body's stabilizing muscles and CNS activation. An experiment is suggested to demonstrate the increase in grip strength when the whole body is engaged, highlighting the interconnected nature of muscle training.

Keywords

💡Leg Day

Leg Day refers to a day in a workout routine specifically dedicated to training the leg muscles, including the quadriceps, hamstrings, and calves. In the script, it is mentioned that skipping leg day can affect not only the development of leg muscles but also the growth of arms, illustrating the systemic effect of muscle training.

💡Anecdotal Observation

Anecdotal observation is the collection of evidence or examples from personal experience or stories rather than from systematic scientific research. The script refers to the long-standing anecdotal evidence in the strength and bodybuilding community about the connection between leg training and arm growth.

💡Systemic Effect

A systemic effect is a widespread influence that affects the entire system, as opposed to a localized effect that is confined to a specific area. The script discusses how training a particular muscle group can have a systemic effect on muscle growth in other parts of the body, not just the trained area.

💡Muscle Atrophy

Muscle atrophy is the decrease in muscle mass and strength due to inactivity or disuse. The script mentions studies showing that if one arm is incapacitated, the other arm's training can reduce atrophy in the non-functioning arm, indicating a systemic response to muscle training.

💡CNS (Central Nervous System)

The Central Nervous System is responsible for coordinating and controlling muscle movements. In the script, it is suggested that the CNS might play a role in the systemic muscle-building effects observed when training different muscle groups.

💡Irradiation Effect

The irradiation effect is a phenomenon where the activation of one muscle group leads to the involuntary activation of other muscles. The script discusses this effect in the context of the CNS and its role in muscle training and growth.

💡Muscle Protein Synthesis

Muscle protein synthesis is the process by which muscle cells create new proteins required for growth and repair. The script mentions that muscle training can increase muscle protein synthesis, contributing to the systemic muscle-building effect.

💡Hormone Levels

Hormone levels refer to the concentration of hormones in the body, which can influence muscle growth and other physiological processes. The script suggests that changes in hormone levels can be part of the systemic response to muscle training.

💡Myostatin

Myostatin is a protein that regulates muscle growth by inhibiting the formation of muscle cells. The script indicates that myostatin levels can be affected by muscle training, which may contribute to the systemic muscle-building effect.

💡Evolutionary Standpoint

The evolutionary standpoint is considering biological processes from the perspective of how they have evolved and their role in survival. The script uses this perspective to explain why the body might have a systemic muscle-building effect to prevent imbalances that could be detrimental to survival.

💡Free Weights

Free weights are exercise equipment that can be moved in any direction, requiring the user to stabilize the weight themselves. The script suggests that free weights may have a greater systemic effect on muscle growth compared to machine-based exercises because they involve more muscle groups for stabilization.

💡Imbalance

Imbalance in this context refers to a disproportionate development of different muscle groups. The script explains that the body tries to avoid imbalances, which can be evolutionarily disadvantageous, and that training all muscle groups helps maintain balance and optimal muscle growth.

Highlights

The concept that skipping leg day can limit arm growth is scientifically supported.

Anecdotal evidence from the strength and bodybuilding community supports the systemic muscle building effects.

Studies show that training one arm can reduce atrophy in an incapacitated arm.

There is a systemic effect from resistance training beyond the trained muscle.

The central nervous system (CNS) may play a significant role in the systemic muscle building effect.

The analogy of an amplifier and speaker is used to explain the systemic effect on muscle growth.

Evolutionary perspective suggests the body avoids imbalances for survival.

Systemic muscle building effect is more pronounced with larger muscle groups.

Skipping certain body parts can impede muscle building effects on other parts.

Free weights generally build more muscle and strength than machines due to the systemic effect.

Upper body is involved in most free weight lower body exercises, contributing to the systemic effect.

The body's response to training can be demonstrated by comparing grip strength with relaxation versus full body tension.

Studies on incapacitated limbs show less muscle loss when the opposite limb is trained.

The body's mechanisms to prevent imbalances are crucial for optimal performance and health.

The importance of training both upper and lower body for overall muscle development is emphasized.

Female clients avoiding upper body exercises can limit their lower body muscle development.

Transcripts

time for some truth if you skip leg day

your arms aren't going to grow as much

either all right let's talk about this a

little bit i remember the first time i

read that somewhere i thought that was

an inch you know i don't remember i

think it was like a um i feel like it

was a t nation article that i read that

where it was like the article was titled

something like um you know hit a plateau

or your arms won't grow then um work on

your squat yeah it was like what yeah i

know yeah that blew my mind so so here's

the science behind it right so and by

the way this has been anecdotally

observed in uh strength building and

must bodybuilding world for a long time

i mean

there were articles

written in the 70s that would talk about

how adding

weight to the squat would get your arms

bigger or if you gained muscle in your

legs you would notice that you get

bigger arms so people have observed this

for a long time

what does this mean like how do we

you know explain this scientifically

well there are studies that show

great studies by the way

where if somebody has let's say an arm

that's broken or an arm that's

incapacitated

it will atrophy less

if you work the arm that's available in

other words

if i break my left arm

i'm better off training my right arm

because it actually prevents muscle loss

from happening in my left arm so

what's happening here in the weights is

explained is that there isn't a

localized acute effect from resistance

training in other words the muscle you

train is going to get most of the muscle

building effects but there's a systemic

effect yeah that happens as well do you

think this is all attributed to the cns

or do you think there's other factors at

play oh that's a good question or is it

just the irradiation effect

which would be the cnn which would be

the cns so it's yeah i mean in terms of

it also being able to stabilize and have

that isometric contraction

uh i'm sure would play a factor in that

because

if i after i read that the way that i

would explain it to like a client and

i wouldn't do it exactly this way but

i'll refine it with your analogy because

i like it so much and i've brought up

your analogy many times on the show

since you've brought it up because i

think it's one of the best analogies and

i think it works here also which is your

um amplifier and speaker analogy and

it's a good example of i don't use it in

your analogy

you just come up with random ones

like rap water yeah well

it's just so uh because this is hard to

explain to somebody right it's like

really like huh squatting more but if

you can explain the the amp and the

speaker analogy then it does make sense

it's like oh even though you're not

directly working on the speaker like for

example or one of the speakers you're

building the amplifier and of course if

you build a bigger better stronger

amplifier

it is going to directly affect

all the other muscles or speakers and so

i think that's how i would explain it to

a client is like even though we may not

be working on these specific speakers

right now by you squatting it's

squatting

amplifier so much to uh building a uh i

don't know the

more sophisticated cns you may say or a

a stronger cns signal yeah because of uh

its difficulty right so and that

carryover bleeds into the other mouth

yeah the systemic effect is very

interesting right there's a lot of

things that happen one is what you're

talking about then there's this like

general

you know increase in muscle protein

synthesis there's these general changes

in hormone levels

myostatin generally gets affected um as

well not just acutely or locally but

also kind of systemically

now i like to explain it from an

evolutionary standpoint i think the body

it to become super imbalanced

is evolutionarily disadvantageous so

although the body will allow you

to build a certain amount of imbalance

in order to make you better at whatever

you're attempting to do a lot of

too much of an imbalance starts to

become a detriment right

and i think that the the the systemic

muscle building effect is larger with

larger muscle groups and smaller with

smaller muscle groups so if i work my

biceps i'll get a localized muscle

building effect of the biceps and i'll

get some small systemic effect overall

but if it's like my lats or my quads or

my glutes or big muscle groups i mean if

you're working out your legs you're

working out half of your body

you get that localized effect but then

you get this again the systemic effect

and so when people skip body parts

they're actually not only are they not

developing the body part that they're

skipping which is most of the effect but

they're also impeding the

benefits or the muscle building effects

that they could get on other body parts

and you talk to anybody who's and i know

i had clients like this where they

skipped leg day all the time

and then they hired me and i'm like look

we can't do that i'm going to train your

legs i'm a trainer i have integrity so

we got to do it and then they also

gained upper body strength and mass yes

and they all comment on it why are my

upper body is getting stronger my arms

feel bigger like what's going on i'll

explain this and say well you know your

body

doesn't want to be that imbalanced

so skipping leg day yeah your legs are

small but your arms are not as big as

they could be as well that's why i

always trip on the human body has so

many of those mechanisms in place to um

prevent a lot of those imbalances from

happening or at least like kind of bring

it back uh to somewhat of a homeostasis

where it's it's most optimal and like

and this is the same thing with like you

know when you're in a state of famine uh

you know you're preserving calories uh

you know it has all these like

mechanisms in place to make sure that

you're utilizing you know the energy the

most efficient way possible totally if

you're training free weights also

there's actually not

very many i actually can't think of any

right now that are free weight i can

think of some machines but if you're

training legs there's you're almost

always incorporating upper body too oh

it's holding there's that factor too

yeah i mean you put 225 pounds or more

on your back um and your shoulders your

upper back your abs and core it has to

account for that load yeah so it's it's

getting worked of course it's not like a

direct

uh effect like if you were to do

shoulder press or do a row or whatever

like that but it's still it's still

getting worked you know so there's got

to be some value in that and right i

can't think of a free weight exercise

that you don't use a body now you could

do leg extensions leg curls leg press

where you where you take the upper body

out of it but most

free weight if not all free weight lower

body exercises still incorporates this

is one of the reasons why i think

generally speaking people debate this

all the time uh but i think if you were

to if you were to interview a hundred

top strength conditioning and muscle

building coaches

a majority maybe not all but a majority

would say that free weights generally

build

more muscle and strength than machines

do and i think that's one of the reasons

why right the free weights have you have

that that localized effect but they have

more of a systemic effect because so

many things are involved you have to

stabilize you have to stand with the

weight typically

if you're working your lower body you're

still holding the weight with your upper

body and all that stuff so

here's another example um if you if

you're watching this right now you if

you have something that can measure your

grip strength

go ahead and try squeezing as hard as

you can while maintaining total

relaxation in the rest of your body

don't grit your teeth don't squeeze

everything totally relax and just

activate your grip and then try it again

even though you might even be a little

fatigued from your first attempt and

then squeeze your entire body and see

how much stronger you are you'll notice

a 10 15 increase in strength by the way

you'll notice how hard it is to activate

maximally while relaxing everything it's

not a natural thing your body wants to

turn on its cns to generate oh i don't

even think you need something to measure

someone right now could literally just

make relax your mouth relax your body

squeeze your hand and then allow

yourself to grit your teeth and squeeze

the other hand and you can instantly

feel your your palm just get tighter oh

totally but the studies on like uh like

right to left like it's so interesting

like you'll have like one leg totally

incapacitated so of course it's gonna

atrophy

they'll train the other leg and they'll

compare this to groups where they don't

train the other leg and they just leave

them both

you lose less muscle

in the leg that's not trained

it's such an interesting but again

evolutionarily speaking it makes perfect

sense i mean our bodies evolved always

trying to make us help us survive

and so all of it makes sense from that

standpoint and like you mentioned you

know famine and metabolism adapting and

uh all that i mean it makes makes

absolute perfect sense but it is

interesting and a lot of people don't by

the way this is true for women too you

want to build big a bigger butt and

you're not working out your upper body

you're not going to build the butt that

you can because you're avoiding uh

training the rest of your point that

there is a lot of my female clients that

would avoid a lot of upper body exercise

especially a chest press or something

like that yes it all works together so

this is all very very important

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