How Do Muscles Grow?

The specifics of muscles growth are not well understood yet.

Yesterdays discussion brought up some questions about the specifics of muscle growth. It seems there is some confusion on what muscle growth even is.

To understand muscle growth we have to first understand what a muscle is made up of.

Skeletal muscles are somewhere in the neighborhood of 80-85% water, this is the fluid that makes up the cytoplasm of each cell. The rest of the structure is a mix of protein and lipids and some carbohydrates.

Glycogen is stored in the muscles as well as some amount of amino acid pool that is in a constant state of flux.

Glycogen is stored in approx a 1-2 ratio with water; for ever gram of glycogen the muscle can store it also needs to store two grams of water. Each gram of muscle protein also seems to require approx 2 grams of water.

The transient states of exercise, or even day to day activity are what determine if your muscles will grow or atrophy. In other words, it’s incomplete to assume your muscles have a standard size.

A more accurate view would be say: How big are you muscles when they are:

A) complete inactive in a cast

B) active from day to day activity but no purposeful weight training

C) stimulated from regular weight training

D) stimulated from drug use (testosterone and GH etc)

E) stimulated from supplement use (creatine, BCAA’s etc)

F) Some combination of the above

Each one of these stimulus (or lack thereof) combined with your genetic predisposition for a baseline of muscle fibers will determine how ‘big’ your muscles are given the state they are in.

The specifics of what even makes a muscle bigger and smaller is still unclear. Some research points to sarcolemma growth while other research suggest sarcomere growth, and still others are assuming both happen along with some degree of hyperplasia and potential fiber splitting.

In any case the size of a muscle is dependent upon a transient state of stimulus. Take the stimulus away and the muscle will atrophy, add more stimulus in and it will hypertrophy, but there are always limits to both ends of the spectrum.

John

Posted by johnbarban in Muscle Building

15 Responses to “How Do Muscles Grow?”

usernametooshortnowitstoolon Says:
June 15th, 2010 at 12:27 pm
Thanks, John, for this very informative post.
Jason Says:
June 15th, 2010 at 12:45 pm
John,
Since muscle size is a transient state, do muscles actually “grow” during rest following a hard training session or do they begin to atrophy to their current environment (ADL or bed rest)?
Jason
johnbarban Says:
June 15th, 2010 at 12:53 pm
They adapt and grow post exercise (2-3 days) then a few more days after that they will start to atrophy if they’re not hit with another stress. So it takes about 7-10 days for them to atrophy back to original state.

JB
Kevin Says:
June 15th, 2010 at 1:36 pm
Thanks for the info John. I appreciate your in depth explanation on the matter.
usernametooshortnowitstoolon Says:
June 15th, 2010 at 2:36 pm
“They adapt and grow post exercise (2-3 days) then a few more days after that they will start to atrophy if they’re not hit with another stress.”

This piece of practical knowledge!
usernametooshortnowitstoolon Says:
June 15th, 2010 at 2:37 pm
Great piece of practical knowledge I mean. We need an edit function here lol
Alex P. Says:
June 15th, 2010 at 3:59 pm
Since muscles are made up of mostly water, how do your hydration levels, both short term and long term, affect your muscle growth?
johnbarban Says:
June 15th, 2010 at 7:51 pm
In some respects the hydration of the muscle IS the growth
Eddie Says:
June 15th, 2010 at 9:07 pm
My workouts are generally 7 days apart (I do workout A on Monday and workout B on Friday). I feel I need this amount of rest to be at my best in the gym. I also tend to think I stay sore longer than the average person and I want to avoid getting injured from exercising a sore muscle.

Is there any benefit to exercising a sore muscle? Is it best to wait for complete recovery between workouts?
Kevin Says:
June 15th, 2010 at 10:29 pm
johnbarban Says:
June 15th, 2010 at 7:51 pm

In some respects the hydration of the muscle IS the growth

SO John how does working the muscle cause an increase in the hydration of the muscle? Is it due to the glycogen and protein being pushed into the muscle there for causing an increase in size?
James Says:
June 15th, 2010 at 11:58 pm
Eddie, I’m training every day now and I don’t get sore anymore. I used to just train heavy once a week and it would make me sore for 5 days or so. Now I train heavy every day and I like I said, I don’t get sore. Interesting phenomenon. Maybe John or someone else knows why it is.
usernametooshortnowitstoolon Says:
June 16th, 2010 at 2:45 am
Soreness is not an indicator of recovery. It’s an indicator of lactic acid. I used to think that I shouldn’t lift again until I’m not longer sore, but I was…sorely wrong!

Unless you’re genuinely in a lot of pain (which usually happens when you haven’t worked out in a LONG time and you hit the weights hard), your body will adapt and not get as sore, if at all. That’s right – soreness is also not an indicator of a good workout, delayed onset or not.
Sandro Says:
June 16th, 2010 at 4:35 am
hi All

strange things about training frequency.I train only 1 x week and nevere seen somenthing like muscle atrophy.every time I train I’ve allway stronger.I thinks that is how much do you challenge your muscles that could control muscle atrophy or not…

ciao
Sandro
usernametooshortnowitstoolon Says:
June 16th, 2010 at 5:59 pm
Sandro, my guess is that the rate of atrophy probably isn’t fast enough to negate the effect of training a week later.
Tips on How to Place in 2 Contests, Lose 100 pounds and Get Ripped Says:
January 16th, 2012 at 1:53 pm
[...] of all, even maintaining your look requires effort. Just like you have to work out to prevent your muscles from atrophying, you also have to do something similar with your diet. If you want to keep the weight off [...]

15 Responses to “How Do Muscles Grow?”

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