Muscular Density

[NeoIncubusX]

Is there such a thing as "muscular density". Like, a smaller person having very "dense" muscles, and a bigger person not having dense muscles? Where a person who was smaller could lift as much as a bigger person.

[Ultra Man]

well yes there is such a thing. fast twitch muscles are very dense, and also the muscle BBers are out to get. then theres slow twitch, which aren't dense to allow better blood flow for endurance tasks like distance running.

thats probly not the answer your looking for though /forum/images/graemlins/wink.gif

[NeoIncubusX]

Lets take the biceps for example then. A guy with little arms curling as much as someone with much bigger arms.

[President Wilson]

Yes,

typically it is called' filament area density' which can be defined as the ratio of filament area to the muscle fiber area.

In this context, the force produced by a muscle is contingent on the outcome activity of its subunits( sarcomeres, myofibrils, muscle fibers). These are the contractile proteins of a muscle fiber.

Therefore the force that a muscle fiber is able to produce is limited by number of actin / myosin filaments.

Filament density is used to measure the strength potential of a muscle fiber as a function of its cross sectional area.

Therefore you take the area that the filaments would take up, and divide it by the total area that the muscle fiber actually is ( cross sectional area).

Various training styles will determine this ratio. For example, when you train, you can increase the cross sectional area of a muscle fiber in two ways

1. You can increase the size of the muscle cytoplasm, known as the sarcoplasm. This is the non contractile aspect of the cell, which includes fluids, glycogen, myoglobin, and various organelles like mitochondria. While it enhances the energetics of the cell, it does not 'directly' cause contraction.
However, a greater glycogen supply would certain augment contraction

2. Myofibrillar hypertrophy - enlargement of muscle fiber as it gains more myofibrils, and consequently more actin and myosin filaments.

Heavier lifts will cause a greater degree of myofibrillar hypertrophy, while higher repetitions will cause a greater degree of hypertrophy of the sarcoplasm itself.

Note however, that 'strength' as measured by filament area density speaks of a single muscle fiber. In vitro, you will find a very high coorilation between this and strength. However, in vivo, when examing a whole muscle it becomes more complex due to neurological components.

[President Wilson]

[ QUOTE ]
Lets take the biceps for example then. A guy with little arms curling as much as someone with much bigger arms.


[/ QUOTE ]

This is an example that is highly dependent on neurological factors, along with filament density.

[NeoIncubusX]

Great answer! Thank you!

[President Wilson]

[ QUOTE ]
Great answer! Thank you!

[/ QUOTE ]

My pleasure /forum/images/graemlins/grin.gif

[rev]

Whoa, sweet response!
[ QUOTE ]
Heavier lifts will cause a greater degree of myofibrillar hypertrophy, while higher repetitions will cause a greater degree of hypertrophy of the sarcoplasm itself.

[/ QUOTE ]
So basically the weight increases muscular hypertrophy and the pump induces sarcoplasmic?

[RaiseDaBar88]

I know this little guy (160 pounds, 5'7) who can bench 315, which is much more than guys I know who weight in at 200+.

The thing is, he has smaller arms than they do? Would that be muscular density?

[Satch]

He has much more dense musclar filaments than most people and he has been trained with nuerophysical adaptation as his main goal for a while..

[RaiseDaBar88]

So he got that way through alot of training?

Also, his family is naturally stronger than most people, probably for the same reason.

[Satch]

[ QUOTE ]
So he got that way through alot of training?

Also, his family is naturally stronger than most people, probably for the same reason.

[/ QUOTE ]

He naturally is strong and he has trained his bench press for quite awhile. I don't care how big or strong you are. No one can get under the bar and press 315 on their first try. He has been doing that for a while.

[monkeyboy007]

After a few months in the gym I was asking myself a similar question and never found the answer, so thanks guys. I knew it! hehee.. but like satch said - noone would be able to hit up 315 or something right away.

Correct me if I am wrong, but leverage in different body shapes will play a minor role, too?

[Ultra Man]

is his chest also small?? have you gotten a good peak at his triceps?? cuz he could have puny biceps, but huge pecs and chest (aka a bench monkey)

[Satch]

[ QUOTE ]
After a few months in the gym I was asking myself a similar question and never found the answer, so thanks guys. I knew it! hehee.. but like satch said - noone would be able to hit up 315 or something right away.

Correct me if I am wrong, but leverage in different body shapes will play a minor role, too?

[/ QUOTE ]

Yeah of course. Take Gene Rychlak for example, the man is the size of a beach ball and has about two inches of fat on his chest that makes it easier for him to press higher weights because of his decreased ROM compared to someone with no body fat on their chest.

[President Wilson]

[ QUOTE ]
So basically the weight increases muscular hypertrophy and the pump induces sarcoplasmic?

[/ QUOTE ]

Hey Rev!


On higher repetitions myofibrillar hypertrophy will occur. But, sarcoplasmic hypertrophy becomes more and more significnat in higher repetitions. It lies along a continuum.

[President Wilson]

Filament density will certainly play a role.

However, it is also in large part neurological.

For example, bodybuilders train for their muscles to respond more asynchronously, than synchronously. Where as a power lifter is t he opposite and can therefore generate more force in a single lift ' relatively speaking '

The power lifter will also fire at full frequency faster than the bodybuilder.

Performance in the bench press, like anything else is a reflection of the way the participant practices

[Ultra Man]

i think im finally starting to put all the peices together. thanks prez...

[President Wilson]

[ QUOTE ]
i think im finally starting to put all the peices together. thanks prez...

[/ QUOTE ]

Thank you for your hard work investigating the subject in reading articles etc.. Its great to see!