Demystifying the Core


Almost every time I’m at the gym, I hear someone talking about the core.

Last week, I happened to overhear a trainer explaining the core to one of his clients. His explanation involved a demonstration of a twist and a kick. He pointed to his hip flexors and said “this is where the core is”.

I cringe when I see or hear people educating others about nutrition, exercise or health concepts that are either confusing or erroneous. I’m sure this trainer had good intentions, as misguided as they were.

What is the core and why is it important?

A good way to understand the core is to think about is as a group of muscles, primarily connected to the spine and pelvis, whose main purpose is to provide stabilization.

Stabilization is the foundation, where the optimum flexibility, joint function, balance and posture result in optimal neuromuscular efficiency (the ability for muscles to accelerate, decelerate and dynamically stabilize movement in all planes/directions of motion).

Functional Anatomy

Conventional approaches to anatomy (as well as exercise), view muscles as having isolated actions and functions.

In reality, muscles act in a more functional manner, i.e. as agonists (prime mover), antagonists (opposing the prime mover), Synergists (assisting the prime move) and Stabilizers (supporting and stabilizing the agonists, antagonists and synergists during movement).

Take for example hip extension. The agonist is the gluteus maximus; the antagonist is the Iliopsoas; the synergists are the hamstrings and erector spinae muscles; and the stabilizers are the transversus abdominus, internal oblique, and multifidus muscles.

If any of these muscles are out of balance then faulty (compensatory) movement patterns occur. This can result in dysfunction, poor performance and eventually injury.

It has been proposed that there are two distinct, yet interdependent muscular systems that enable our bodies to maintain proper stabilization and ensure efficient distribution of forces for the production of movement.

Muscles that are located more centrally to the spine (the Local or Stabilization System) provide intersegmental stability (support from vertebrae to vertebrae), whereas more lateral muscles (the Global or Movement System) support the spine as a whole.


The Local Muscular System (Stabilization):

  • Provides joint stability and support to allow movement at a joint
  • Located in the spine e.g. transversus abdominus, multifidus, internal obliques, diaphragm and pelvic floor muscles or peripheral joints, e.g. the rotator cuff
  • Are biomechanically less advantageous to manipulate movement of a joint and are therefore better suited for stabilization.  These muscles show a propensity to inhibition or weakness


The Global Muscular System (Movement):

  • Responsible predominantly for movement and consist of more superficial musculature that originate from the pelvis to the rib cage, lower extremities or both, e.g. rectus abdominus, external obliques, erector spinae, hamstrings, gluteus maximus, latissimus dorsi, adductors, quadriceps and gastrocnemius.
  • Are larger and associated with movements of the trunk and limbs
  • Have greater biomechanical advantages to manipulate movement of joints.  These muscles show a propensity to become tight or overactive


The Global/Movement system can be further broken down into four subsystems:

  1. The deep longitudinal
  2. Posterior Oblique
  3. Anterior Oblique
  4. Lateral


For the sake of simplicity, the purpose of categorizing the movement system into these sub-systems is to identify Force Couple relationships (synergistic action of muscles to produce movement around joints).

In Summary

The core is the center of the body and the beginning point for movement.

The core is considered the lumbo-pelivic-hip complex that operates as an integrated functional unit providing intersegmental stability, deceleration and force production during activities.

There are between 29-35 muscles that attach to the core from the spine as well as the upper and lower extremities.

It is important to consider all these anatomical relationships when strengthening the core as well as the functional relationships mentioned above, where muscles can take on the role of being agonists, antagonists, Synergists and Stabilizers depending on a movement or activity.

Strengthening the core should be done from the inside out, i.e. training the stabilization system first, in order to build a stable foundation. If the movement system musculature of the core is strong and the stabilization system is weak, the body senses imbalances and compensates through synergistic dominance (over activity of helper muscles), which results in inefficient movements.

In order to effectively stabilize the core, to prevent injuries, move efficiently and perform optimally, an assessment should be performed to identify where one’s unique deficiencies are so that a program can be designed address the specific needs of that individual.


Dr. Lecovin is a chiropractor, naturopathic physician and acupuncturist. He graduated from Los Angeles College of Chiropractic in 1990, earned a Masters in Nutrition from the University of Bridgeport in 1992, and then went on to complete the naturopathic and acupuncture programs at Bastyr University in 1994. He holds additional certifications in exercise from the National Strength and Conditioning Association, National Academy of Sports Medicine and International Society of Sports Nutrition.

Dr. Lecovin specializes in treating musculoskeletal pain and sports injuries by integrating trigger point acupuncture, soft tissue release, joint manipulation, corrective exercise and nutrition. In addition, he combines exercise and nutrition for weight loss, weight gain and performance enhancement.

His clinic, located in Bellevue, WA, offers naturopathic medicine, chiropractic, acupuncture, massage and infrared sauna therapy.

He can be reached at Evergreen Integrative Medicine at (425) 646-4747 and his website address is:

About the Author

Dr. Geoff LecovinNaturopathic Physician/Chiropractor/Acupuncturist/Certified Strength and Conditioning Specialist/Corrective Exercise Specialist/Performance Enhancement Specialist/Certified Sports Nutritionist/View all posts by Dr. Geoff Lecovin