Abs & TvA

[Guest guest]

Casler wrote:

, please tell me you know how the TvA works, and this is a joke.

Scherger wrote:

I am still trying to understand how Tva stabilizes trunk. The diaphram is

muscle like TvA. It does not attach from one bone to another bone crossing

a joint. Its fibers like TvA terminate in a central tendon/ligament.

Casler writes:

I find it truly amazing that you claim to understand the physics and

biomechanics of the spine, yet don't even know the elementary functions of

the abdominal complex in stabilizing the trunk and torso.

Do yourself a favor and re-visit the ThoraColumbar Fascia, and report just

how it functions.

The TvA connects to and affects the function of the ThoraColumbar Fascia.

Scherger wrote:

When the diaphram contracts it depresses the abdominal contents. I do not

think at this point that by depressing the abdominal contents the diaphram

is stabilizing anything.

Casler writes:

If you do not, then you are incorrect, and do not understand.

Scherger wrote:

Or anyone is trying to say that any bones or joints are stabilized abdominal

contents being compressed downward and therefore against the trunk. Tell me

if someone thinks trunk stabilization takes place by this action.

Casler writes:

That is what I have been trying to do.

Go into your bathroom, grab a full tube of toothpaste. Grip it in the

middle and " squeeze " . As long as you are squeezing the internal pressure

inside the tube will resist forces to the ends of the tube.

Any light bulbs?

Why do you think we " reflexively " perform Valsalva, and create IAP and ITP

when we need to stabilize the torso? You do know this happens...right?

Scherger wrote:

The degree that the abdominal (liver for instance) contents cannot be

compressed anymore and then the central tendon of the diaphragm becomes

fixed or becomes and origin of attachment. Meaning the origin becomes point

that the tendon is fixed by the point it is fixed by liver and then further

contraction on the lower ribs now that they have become the insertion, they

are pulled upward and elevated.

Casler writes:

If we have compressed the abdominal contents to the point they cannot be

compressed any further, imagine how well they would resist a load to the

anterior disc. Couple that with the stabilization of the lateral tension of

the TcF (ThoraColumbar Fascia) and the coordinated tension of the spinal

extenders (used only as stabilizers) and you have a much more stable spine

and torso.

Scherger wrote:

At this point I could see by stretchig my imagination one could say that the

trunk through the ribs are able to be acted upon to become more stable

relative to a movement that would depress the ribs. Meaning diaphram

elevates the ribs so this stabilize against movement that would depress the

ribs.

Casler writes:

, ever notice that the Thoracic discs are much smaller than the Lumbar

discs? Yet there is a much higher incidence of disc pathology to the lumbar

discs, which while bigger and stronger have no ribs. Do you know why that

is?

Hint: Each of the thoracic vertebrae has a rib attached to it that

" resists " (through a highly leveraged system) anterior flexion/compression.

Scherger wrote:

Now back to TvA. It like the diaphram does not possess a insertion on one

bone to another bone that crosses a joint. It depresses like the diaphram

the abdominal contents.

Casler writes:

Again, take an anatomy/biomechanics course on the ThoraColumbar Fascia. It

attaches directly to the spinal processes. What? You think it is there

just to take up space?

Scherger wrote:

But unlike the Diaphram I can not see where the TvA reaches or develops a

fixed point from which it develops an origin to function from.

Casler writes:

The TvA compresses the abdominal contents and helps raise IAP. This (as you

hopefully have found out by now) tensions the Thoracolumbar Fascia to the

lumbar spine, creating a lateral stabilizing tension. This coupled with the

IAP forces on the internal abdominal walls anterior to the spine, provide

significant stability.

When it is forced into eccentric action, this " tension " also resists forces

and movement from loads and shears to the spine.

Scherger wrote:

I still can not see how then the TvA stabilizes the trunk or lumbar spine.

For instance if I was going to depress the ribs the diaphram could reach a

fixed point where it possessed a direct line of pull to the ribs that would

stabilize or oppose their depression.

So Thinking I could take the trunk and want to flex, extend, laterally flex

or extend one lumbar vertebra on another vertebra or the vertebra on the

sacrum C. could you a put into words a little more explaination how you

see the TvA stabilizes against one of these movements.

Casler writes:

, what you need to see, is that the spine is but one a part of the

torso. The Torso and all its components, create, transmit and absorb force.

Focusing and analyzing the spine by itself will not tell you what forces are

at play nor will the physics be correct.

I think the above explanations should have already supplied you with the

information needed (as long as you refreshed yourself on how the TvA works

with the TcF)

Scherger wrote:

Now speaking of the IAP. Are you suggesting that the TvA will compress the

contents of the abdominal cavity (spleen, intestines, gall bladder etc.) to

the point that lumbar vertebra are held in place by these organs compressing

into the vertebrae. Compressing to such an extent that for instance the

trunk or lumbar spine can not be extended or flexed and there for stabilzed

against force that would cause extension or flexion.

Casler writes:

No, not " just " the TvA, for it is a rather weak muscle. These pressures are

created by a whole system, which includes the glottis, the lungs, the ribs

and their musculature, the diaphragm, all the abdominal muscles, and the

ThoraColumbar Fascia.

Just go in the bathroom and grab a full tube of toothpaste and grip it as I

described above. ITP and IAP are easily modulated, and for the most part

reflexively controlled aspects of the TSM (Torso Stabilization Mechanism).

Please know that they are " only part " of the mechanism.

Once you " grasp " this portion of the TSM, then you will see why I have

questioned your physics models and why they are not accurate.

Regards,

Casler

TRI-VECTOR 3-D Force Systems

Century City, CA