The “Abs”
Without question, the generally-referred to “abs” (region of the anterior and posterior abdominal
walls) emerge as the most neglected area of the entire muscular system. If you were to walk in to any
bustling health club at peak period you would expect to see the wall-to-wall mirrors reflecting a wallto-
wall sea of weight-training enthusiasts grunting and straining in pursuit of bigger muscles. Every
available bench in the heavy section will be bearing the burden of the maximum loading applied by a
plethora of training zealots, and the long line up to the pec-deck means you would be wise to opt for
a free-weight flye application instead. However, the number of people that are attacking their “abs”
can be readily accommodated with the utilization of a single sit-up board.

No one would consider preparing for a contest without including a very arduous abdominal routine
into the program. In fact no trainee could consider him/herself serious without the inclusion of
a comprehensive abdominal training program. Even occasional trainees would consider leaving out
their chest and back or shoulder routines. Leave out biceps and triceps? You must be staying out in
the sun too long! No one would leave their shoulders out of their training schematic nor would they
exclude their leg training from their program. How is it then that anyone could consider leaving out
their “ab” training for weeks on end? (If in fact, they had a abdominal routine to leave out). The
same degree of devotion that is paid to the other body parts should be extended to the abdominals;
otherwise hopes for a truly well-developed physique cannot be held with any degree of seriousness.

Location and Function
As a logical pre-requisite to any body-part training it would be necessary to garner a complete
understanding of the muscles that comprise the particular region under scrutiny before any attempt
was made to explain the proper movement methodology of the muscles, or any effort was made to
develop a routine of exercises for the specific body part. When reference is made to the abdominal
wall (anterior, posterior regions) the considerations for the importance of gaining a thorough awareness
of the muscles of the region takes on even greater significance.

In order to provide for a well-designed program of exercises that would effectively stimulate the
muscles of the region and at the same time, provide for reduced injury-risk potential, it would be es-
sential that the trainee understand the relationship that exists between the muscles of the abdominal
wall (anterior and posterior regions), and the vertebral column. It is also vital that the trainee be
aware of the biomechanical association that is shared by the two regions in order to avoid wasting
time and energy in futile search of superior abdominal development. Even more crucial, is the concern
of avoiding the risk of serious injury which can often occur as a result of ignorance of proper
execution of the abdominal exercises. Aside from providing for the finishing touches to the wellhoned
physique, good abdominal development can provide for a measure of injury prevention for
the always highly-vulnerable lower lumbar region. However, poorly-advised movements can not only
fail to provide for the hoped-for results, but can lead directly to serious injury. Proper awareness of
the location and function of the muscles of the anterior and posterior abdominal would be of extreme
benefit to those seeking safe, efficient training approaches for the abdominal muscles.

No Skeletal Support
The abdominal region receives no skeletal support within the abdominal cavity. The area derives
its strength and integrity entirely from its muscle structure. The abdominal region is comprised of
three layers of muscle with each having its fibers running in a different direction. This phenomenon
of different fiber direction provides the required tension and strength which makes up for the lack of
bony structure in the area.

The abdominal muscles almost exclusively create the abdominal wall. These muscles provide
support, as well as protection, for the abdominal organs, and they provide assistance to the diaphragm
during respiration. The abdominal serve to flex the vertebral column and depress the ribs. The
contraction of the abdominal raises the intra-abdominal pressure which is necessary for defecation
and contributes to the stability of the thorax in times of strain such as heavy lifting. When the legs are
raised from a supine position the abdominal serve as fixators of the pelvis from which the hip-flexor
muscles originate.

Rectus Abdominis (A)
Location
The rectus abdominis muscle represents the main abdominal muscle and forms the prominent
ridges of muscle mass in the frontal abdominal region. The rectus abdominis is a narrow flat muscle
situated on the ventral aspect of the abdominal wall. The muscle runs vertically across the abdominal
wall from the crest of pubis bone to the cartilage of the fifth, sixth and seventh ribs. The rectus abdominis
has a right and left portion that is separated by a one-inch tendinous strip (linea alba). Each
rectus abdominis is covered by the fascia of the oblique and transversus muscles. Each set of rectus
abdominis is cut by three tendinous inscriptions that provide for a distinct division of muscle that
rises above the separation.

Function
The rectus abdominis act to compress the abdominal cavity and assist in the actions of forced
expiration, defecation, and urination. The rectus abdominis also acts to produce lateral-flexion (sidebends)
and also serves to flex the vertebral column during the action of spinal-flexion. The concepts
relating to the ability to produce spinal-flexion (as opposed to hip-flexion) form the crux of the discussions
on abdominal training and will be explored in detail in the pages that follow.

The Oblique Muscles

External Oblique (B)
Location
As the name would indicate, this muscle originates on the external surface of the rectus abdominis
on the lower eight ribs of the upper end of the ilium, the pubis crest, and the lower portion of the
linea alba. Its fibers run diagonally and upward and in a horizontal direction from the lower end of
the abdomen. The muscle inserts on the linea alba and the anterior portion of the iliac crest.

Function
The external oblique joins the rectus abdominis in the actions of forced expiration, defecation,
and urination. It also serves in the actions of flexion and rotation of the vertebral column.

Internal Oblique (C)
Location
The internal oblique lies just beneath and internally to the external oblique and its fibers run upward
and medially to connect with the internal intercostals muscles that cover the ribs. This muscle
officially on the iliac crest and the lumbodorsal fascia and inserts on the linea alba, the pubic crest,
and the first to fourth rib.

Function
Compresses the abdominopelvic cavity and assists in the action of flexion and rotation of the
vertebral column.
It should be noted that despite their location in the anterior region of the abdominal wall, the
above-listed abdominal muscles have a profound effect upon the function of the vertebral column.

Transversus Abdominis (D)
Location
This little known abdominal region muscle originates on the iliac crest, the lumbodorsal fascia
and the costal cartilages of the last six nos.

Function
The transversus abdominis compresses the abdominopelvic cavity.

Posterior Abdominal Wall
Quadratus Lumborum
Location
The quadratus lumborum is a long thick muscle which originates on the iliac crest and the iliolumbar
ligament and inserts on the lower region of the twelfth rib and the transverse process of the
upper lumbar vertebrae.

Function
This muscle has an even greater (direct) effect upon the lower back as it is responsible for the action
of pulling the thoracic cage towards the pelvis and is also involved in the action of same-side
abduction of the vertebral column. It assists the oblique muscles in the action of lateral-flexion (sidebends).

Erector Spinae Group
Iliocostalis Thoracis/Iliocostalis Lumbar/Longissimus Dorsi/Spinalis Dorsi

Location
The erector spinae muscles are all intertwined and as they all work in harmony with one another
they are considered as one muscle. This group provides the ridges aside a deep groove that is visible
in the lower back of highly-developed body-builders. The erector spinae group covers a large area
originating from the neck and running down into sacrum on both sides of the spine. Specifically
these muscles originate on the crest of the ilium, sacrum (lower surface), the borders of the lower
seven ribs, as well as the spinous process of the entire group of lumbar vertebrae and the lower four
thoracic vertebrae. These muscles all insert on the transverse processes of all the vertebrae.

Function
These muscles would be highly activated during the action of spinal rotation. In the twisting exercise
for example when the shoulders rotate around the spine, the spine provides the axis of rotation
with the externals working on one side in correlation with there opposite-side counterparts establishing
a pulling or torque action across the abdomen.

Iliopsoas group

Psoas Major
Location
The psoas major also comprises the region of the posterior abdominal wall but it acts principally
on the femur bone. It shall however be included in our discussion on the muscles of the posterior
abdominal wall. A long thick muscle, the psoas major originates lateral to the lumbar region of the
back and inserts on the vertebral discs of the lower lumbar region.

Function
The psoas major is involved in the action of hip-flexion which occurs during the leg-raise (off
the floor), seated knees-to-chest and vertical knees-to-chest exercises.

Iliacus
Location
The iliacus is a large triangular-shaped muscle that is situated on the lateral portion of the psoas
major. Its fibers run downward and inward most of which attach to the psoas tendon and inserts on
the lesser trochanter of the femur.

Function
As the muscle crosses over the hip-joint, it serves in the action of hip-flexion and joins in the actions
of the psoas major to function during the leg raise action (off the floor) or knees-to-chest
(seated and vertical) exercises.

Psoas Minor
Location
This muscle is a relatively ineffective muscle due to its long tendon and small muscle construction.
It originates from the last thoracic and first lumbar vertebrae and inserts on the pubic bone of
the pelvis.

Function
The psoas minor serves to support the action of hip-flexion of the psoas major and iliacus muscles.

Muscle Activation
It can be readily acknowledged that working the “abs” is hard work and even more discouraging
is the fact that it is extremely boring to most trainees. After all, where is the fun found in working so
hard and not gaining the satisfaction of witnessing a “pump”? Besides, ab routines rarely produce the
results that are achieved with the other body-part routines. Why don’t we achieve the same response
in the abs as we do with arms and legs and chest etc…? Well we just might be getting results that
simply are not showing because the muscle that is being developed is hidden under the layers of
excess weight that is all-too-frequently carried by the majority of the population (approximately
90%).

Considerations for the Actions of Spinal or Hip-flexion
In order to maximally stimulate the muscles of the abdominal region it is necessary to apply an
action of spinal-flexion. What frequently occurs is that in quest of developing his/her abdominals,
the trainee embarks earnestly on a routine of “so-called” abdominal exercise which, in fact, does not
emphasize the abdominal, but instead provide activation of the hip-joint (flexors and extensors)
muscles. Activation of the hip-joint does not provide maximum stimulation of the abdominal region,
and as a result, the individual’s abdominal region remains underdeveloped.

For example, have you ever felt compelled to put a halt to a series of sit-ups due to the fatigue
experienced in the frontal thighs (as opposed to the desired “attack region” of the abdominal?) This
is simply because the thighs were receiving the brunt of the load during the movement and as a result
the abdominal were left far less stimulated than they should have been in order to provide for maximum
growth and development.