Fit woman looking down at her abdominals with a chalkboard in the background. How to get the most out of your core training
Fit woman looking down at her abdominals with a chalkboard in the background. How to get the most out of your core training

How to Get the BEST Results from Core Training


As trainers it is important for us to have a good understanding of core anatomy and function when training our clients. Especially those clients with Low-Back Pain.

Although many clients tend to be more concerned with “are ab exercises necessary for a six pack?”, “will core exercises flatten my stomach faster?”, “are core exercises necessary?”, we as trainers know how important training the core is to the overall function of the body and will need to educate our clients along the way.

Once we have a clear understanding of how everything works together we can make good exercise selections to work all aspects of the core.

Core Stability

There are nearly 30 muscles in the abdomen, low back, pelvis and hips which attach to the axial skeleton (trunk) as either an origin or insertion site.

Illustration of the skeletal core anatomy
  • These muscles work to transfer forces to and from the upper and lower extremities. This is often seen in sports e.g. a baseball pitch
  • For successful performance of most gross motor activities, core stability is a key component (Wilson et al., 2005)

What is core stability? It has been identified as:

  • Absence of ligamentous laxity in the vertebral column
  • Hip and trunk muscle strength
  • Abdominal muscle endurance
  • The ability to maintain a particular spinal or pelvic alignment

The muscles that make up the core contribute to the stability of the trunk via:

  1. Intra-abdominal pressure
  2. Spinal compressive forces
  3. Hip and trunk muscle stiffness
  • The transverse abdominis, together with the multifidi muscles of the spine, play a critical role in core stability (Hodges, 1999; Hodges & Richardson, 1999, 1997). Co-activation occurred before any movements of the limbs
  • Providing feedback to the Central nervous system about impending dynamic forces makes them a vital role in spinal stabilization (Fredericson & Moore, 2005)
Illustration of the major peripheral nerves

All of which are the capacity of these tissues to resist internal and external loads (Willson et al., 2005)

Core Anatomy

Our core anatomy consists of different layers of muscles which have specific roles to play in movement and stabilization.

  • The superficial muscles are larger and have the responsibility of movement and force transfer between the pelvis and ribcage.
  • The smaller, deeper muscles have the responsibility of stabilization of the spine and inter-segmental motion.
  • The transverse abdominus is the key muscle which works with the neural subsystem. It’s primary function is to increase intra-abdominal pressure which will reduce compressive forces along the spine.
    • In healthy individuals this muscle will fire, reducing compressive forces when loading of the spine is voluntary or involuntary (Hodges & Richardson, 1996; Hodges et al., 1996)

Here is a review of muscle anatomy based on function and location:

Deep Layer:

  • Also known as the inner unit
  • Consists of small muscles
    • Intertransversarii, interspinali, rotatores
  • These span only a single vertebra therefore adding stabilization of each vertebrae
  • They offer most of this stabilization at the end range of the motion
  • They are rich in sensory nerve endings

They will provide feedback to the brain as to what is happening to the spinal position

Middle Layer:

  • Is like a box which spans multiple vertebrae from the pelvic floor right up to the diaphragm
  • These muscles and fascia create a corset like structure. Back, front and sides.
Illustration of the transverse abdominus, internal abdominal oblique, external abdominal oblique, and rectus abdominus muscles
Illustration of the diaphram muscles in the human body

Consists of these muscles:

  • Transverse abdominis, multifidi, quadratus lumborum, posterior fibers of the internal oblique, the diaphragm, and the pelvic floor musculature.
  • Also includes the adjoining fascia: linea alba, thoracolumbar fascia

This layer is important in providing a working foundation on which the body can operate by allowing the spine and sacroiliac joint to stiffen in preparation of movement and loading.

Outer Layer:

  • Muscles that span many vertebrae
  • They are big and powerful muscles
  • Are involved in gross movement of the trunk
Illustration of the abdominal outer layer muscles
Illustration of the spine muscles in the human body
Illustration of the iliopsoas muscle

Consists of these muscles:

  • Rectus Abdominus, internal and external obliques, erector spinae group, and iliopsoas
  • Without thinking about it this muscle will stabilize the spine under loading (voluntary or involuntary)
  • Aids in postural balance during activity
  • Optimizes force production, transferring it through the trunk to our extremites
  • Improves our balance, coordination, control and dynamic postural strength

Training the Core

Effective core training must ultimately simulate the movements and patterns of daily living as their involvement is dynamic.

Woman in a gym with arms over her head stretching

Core endurance training verses core strength training:

  • Endurance training should take precedence over strength as muscular endurance better correlates with spinal stability and a lower risk of injury (McGill 2007)
  • Bracing verse hollowing:
    • Bracing which is the co-contraction of both the core and abdominal muscles is a better choice over hollowing as it creates a more rigid and wider base of support for spinal stabilization (McGill, 2007, 2004; Gambetta, 2007)
  • Intra-abdominal Pressure:
    • A contraction of the inner unit muscles, primarily the transverse adbominis which pulls on the linea alba, which pulls the abdominal wall inward and upward.

Trunk Flexors: muscles found on the anterior and lateral surfaces of the trunk

Illustration of a skeleton with the trunk flexor lateral muscle group
Illustration of a skeleton with the trunk flexor anterior muscle group

Muscle Groups: rectus abdominis, internal and external oblique, and the transverse abdominis.

Actions: Flexion, lateral flexion and rotation

Planes of motion: sagittal plane, frontal plane, transverse plane

Illustration of the rectus abdominus muscle group

Rectus Abdominis:

  • Fibers are superficial and run longitudinally from the lower part of the chest to the pubic bone

Contraction of both the right and left sides results of flexion of the spine/trunk

Exercise example: Supine Curl

  • Muscles contract concentrically on the upward phase of the exercise
  • The same muscles contract eccentrically on the downward phase of the exercise

Unilateral contraction results in lateral flexion of the spine/trunk

Exercise example: Side bend

  • Working side: eccentric contraction as you go into the side bend, concentric contraction as you bring yourself up to neutral.

Some movement exercises to develop this muscle are:

  • Posterior pelvic tilts
  • Supine abdominal curls
  • Reverse abdominal curls (eccentric action emphasized)

This muscle group is best worked isometrically as a stabilizer which is more functional to its daily use. 

Exercise examples:

  • Dead bug
  • planks

External Obliques:

  • Also a superficial layer of the trunk muscles
  • Fibers run diagonally downward and forward. Like putting your hands into your front pockets.
  • When both sides contract together they create flexion of the spine/trunk
  • When contracted individually they create lateral flexion of the spine/trunk
  • When contracted (eccentric) in conjunction with the opposite internal oblique (concentric) they create rotation of the spine/trunk to the opposite side

Exercise example: rotational crunch

  • shoulder moving towards the opposite hip.

Some effective exercises to develop this muscle are:

  • Supine pelvic tilts
  • Abdominal curls with legs partially extended
  • standing pulley rotational woodchop
  • Side plank
Young woman dong a crunch on a blue stability ball with blue dumbbells in the foreground

Internal Obliques:

  • Found deep to the external obliques
  • Fibers run diagonally downward and back. Like putting your hands into your back pockets

Some effective exercises to develop this muscle are:

Two young women doing a side plank on a carpet in their home
  • Supine pelvic tilts
  • Reverse abdominal curls
  • Side plank

Transverse Abdominis:

  • Found in the deepest layer of the abdominal wall
  • Knowing how to activate this muscle is a very important aspect of core stability.

Exercise example: Deep bracing:

  • supine on floor with knees bent and feet flat, pull belly button in towards the spine without moving any other body part

Some effective exercises to develop this muscle are:

  • Static:
    • Plank, side plank
  • Dynamic
    • Hip Bridge with alternating leg lifts while having shoulders/head on a stability ball
    • Abdominal rollouts with a stability ball
Woman doing one legged plank on a stability ball in a gym

Trunk Extensors: the erector spinae group

Muscle Groups: iliocostalis, logissimus, and spinalis

Actions: trunk extensions and hyperextension

Planes of motion: Saggital, frontal transverse

Illustration of the human muscular system showing the erector spinae group

Erector Spinae group:

  • When acting bilaterally they create extension and hyperextension of the spine/trunk
  • Standing and bending forward they contract eccentrically to control the movement against gravity
  • When stimulated unilaterally they cause lateral flexion to that same side although the level of activity in the muscles is quite low in a standing position

Some effective exercises to stretch and mobilize this muscle group are:

    • Cat to Cow on all fours
    • Posterior pelvic  tilt

Some effective exercises to develop this muscle group are:

  • Prone hyperextension
  • Bird dog
  • To challenge add a ball to develop balance and proprioception along with strength.
Woman on a black yoga mat doing a bird dog exercise with arm and leg extended

Works Cited:

Harter R., Jo S., ACE, Essentials of Exercise Science, 2017, pp. 130 – 135
Antonacci D., Esses S., Kohl H., ACE Clinical Exercise Specialist Manual (2007),pp., 338-345
ACE Personal Trainer Manual fifth edition, (2014)
Delavier F., Strength Tranining Anatomy (2001) Human Kinetics
Jarmey C. , The Concise Book of Muscles, (2003)
Nelson A., Kokkonen J., Stretching Anatomy second edition, (2014) Human Kinetics
Curr Sports Med Rep. 2008 Feb;7(1):39-44. doi:10.1097/01.CSMR.0000308663.13278.69. Core stability exercise principals
Ahmet GÖKKURT, Research Assistant, Gazi University. Feb. 2018. Effects Of The Core Stability Exercises On Balance And Hand Functions
Healthwave, Exercise and Cumulative Trauma Disorder (2005)


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