Ab activation

[Jagermeister]

Thought it was a good acticle,
supertraining list part 1



Why is sucking in the abs wrong when lifting? Why is it true that,
"The last thing that any serious lifter would do in weightlifting or
powerlifting is suck in the abs or think about selectively activating some
or other muscles of the abdominal group?"

John Casler writes:

Hi Bryan, It seems that this controversy will not die. The very
interesting thing is it is based on what I think are some difficult to
understand concepts on
both sides.

First off the TvA, Internal Obliques and Rectus are all connected via the
Linea Alba. This means that when one contracts they all are somewhat
affected. I also question that they can be "totally" isolated from each
other. I do acknowledge that you "can" activate the TvA to "compress" the
contents of the lower abdomen. This you can easily do as you read this,
sitting at your desk. But if you then consciously then activate the IO and
RA, (which is a must to support large loadings) you may notice a "slight"
bulging, due to the muscles involved shortening and thickening.

I honestly have not studied "firing sequence" studies if they exists, but I
would say that in dynamic loading situations of sufficient magnitude they
all three fire in concert and as needed.

It does not take a rocket scientist to just look at the insertions of all
three muscles involved and see what the result of their concentric
contractile action would be. When a muscle contracts, "it shortens". As
the TvA contracts longitudinally across the lower abdomen, it shortens,
this causes it to compress and "pull" into the abdominal organs and tighten
against their contents.



Let me make it perfectly clear, the TvA, or for that matter the IO and RA
"cannot" PUSH OUT in their function. The Rectus and Internal Obliques
"can" contract out a small degree "if" they are flexing the spine, but in a
load bearing static contraction (without spinal flexion) the outward action
is rather small and limited to expansion due to shortening. Before you
"pushers" begin to see red - read on.

[Precisely! - as is constantly stressed in functional anatomy texts and EMG studies,
the bulging of the abdominal region is entirely passive and a result of increased
intra-abdominal pressure. Mel Siff]

I am also saying that they are NOT "sucked in" when we perform a heavy lift.
"Sucking the abdominal wall in, involves a complex maneuver of the diaphragm
and a few other muscles. Additionally, to "suck" one must create a "negative
pressure" to do the sucking. the TvA cannot perform this function. It can
only provide a "positive pressure" or compression.

[This is an important point to note. As I stated in the "Facts & Falllacies of Fitness" book,
"it would appear to be more fundamental to focus on controlling breathing patterns
than trying to activate transversus, a muscle which may well become involved quite
reflexively by changes in abdominal pressure associated with action of the diaphragm. Mel Siff]

SO TvA, IO, and RA do no sucking or pushing.

Let us continue; To achieve the maximum compression of the abdominal cavity
all three muscles must contract and maintain tension causing a more rigid
reinforcement on the top of the TvA activation.

These muscle are arranged in such a way that the fibers of each, run at
oblique angles to the others, causing them to be, not only incredible
containment walls for IntraAbdominal Pressure, but when fully tensioned,
they take on a rigidity that rivals many solid tissues. When this rigidity
is combined with the internal "pressurization" (IAP) their ability to resist
force loadings is far greater than one would think.

So why do so many "experts" say that the abs "push" out??

 

[Jagermeister]

Well the abs themselves, do not "push out" as their functional action does
not allow this. As I said above, how could a muscle contracting IN, "push
out". It cannot. No more than your biceps can extend your elbow, it
cannot.

They are pushed out by something else. So what does the pushing? Other
muscles and forces must come into play. Particularly the diaphragm,
thoracic muscles and IntraThoracic Pressure. The ITP "force from above"
comes down.

[Exactly! For those who doubt even the practical evidence that John is offering below,
EMG studies (Basmajian, "Muscles Alive") make this point abundantly clear. Mel Siff]

See for yourself, stand in from of a mirror and force all the air out of
your lungs and try to push the abs out without Valsalva or air in the lungs.
Aside from a bit of contractile bulging, they cannot be "pushed out". Now
take a deep breath and try again. You can look pregnant if you like. Quite
a difference.

Here is where things get interesting. In lifting a large weight, the lumbar
spine is virtually the only "solid" structure from the pelvis to the
ribcage. This means that the torso has to create a rigid support structure
to help support any loading and protect the spine.

To do this for larger loadings, we take a semi-deep breath and close the
glottis. This traps the air in the chest cavity and creates IntraThoracic
Pressure. This pressure has some "extreme" capabilities. To get an idea,
you car might weigh 4000 pounds and it is supported by rather pliable rubber
tires filled with probably 30+ pounds of air pressure. If you hit a pot
hole, the amount of load the tire supports is tremendous.

Although I do not know the PSI involved in ITP and IAP, the research usually
says that it is rather low, which shows just how supportive these pressures
are even at low levels.

The upper torso musculature combined with a semi-rigid ribcage compresses
this cavity even further creating greater amounts of ITP. This pressure
looks for an escape avenue. The path of least resistance is the diaphragm.
Now the diaphragm is an interesting muscle and may be already "pushed"
somewhat up into the thoracic cavity by the compressed abdominal organs we
talked about earlier.

[Zatsiorsky has summarised this pneumatic bracing effect quite neatly in his book,
"Science and Practice of Strength Training". Mel Siff]

This (ITP) pressure pushes the diaphragm down into the already compressed
abdominal organs, creating even greater IAP.

Because the abdominal organs and fluids are non compressible, they too look
for an avenue of escape, and the area of least resistance is the frontal
abdominal muscles. THIS causes them to bulge as this pressure overcomes the
eccentric force tension of the abs.

[Note that one may only refer to a muscle action as "eccentric" if there is ongoing
movement. Once movement ceases and we have equilibrium between imposed force
and muscular tension, then the action becomes isometric. Any other bulging is due to
stretching of the connective tissue components of the muscles involved. Mel Siff]



Because these muscle are being eccentrically activated, they are in a highly
tensioned state, and the only way they can be "pushed out" is by very high
force. And as I stated the reason pushing them out is so difficult is
because to move them we must overcome their eccentric strength abilities, so
it is "very" difficult to push them out, but it can be done. This does not
reduce the pressure by much if anything at all.

What it does, effectively, is create a greater cross-sectional area of almost
"solid" pressurized torso to not only help support the load but through a
very intricate series of incredible biomechanical actions reduces the severe
load on the spine.

And the beautiful thing about this pressure and all the balanced supporting
co-contraction, is that it can be adjusted by the body either consciously or
reflexively to accommodate the needs of the body.

So I hope you can all see, that in reality, we don't "suck in" (but the TvA
does contract inwardly, it has no choice) and we don't really "push the TvA
out" because the TvA does not have the capacity to "push" - it can only pull.

But we do, through the use of these other muscles and pressures, cause the
abdomen to be "pushed out" and this pushing out (under pressure) can help us
to resist greater loads.

This intricate and very incredible process is an engineering marvel. It
takes thousands of loosely connected pieces of soft and hard tissues and
allows them to act in concert to lift, support and resist unbelievable
external forces. Lest you get the impression that I think I know "all" that
is happening here, let me assure you I do not, but I do know some of the
foundational forces and there are hundreds, if not thousands more.

[That is a bit of hyperbole, but does not diminish the relevance of what you have
written! The number of forces in any system also depends on how many components the
engineer or scientists chooses to label acting along and about any axis of reference.
Thus we can reduce 100 forces acting in a given plane to a single force, by successively using basic
methods such as the parallelogram of forces, or mathematically summating all of the components
along mutually perpendicular axes, etc. Mel Siff]

I hope I have been able to explain this in a way that makes sense and
provides you with a mental picture and better idea of how I see these
particular biomechanical functions.

Regards,

John A. Casler
TRI-VECTOR 3-D Force Systems
Century City, CA