By Cindy Abrami, NASM-CPT/CES, UESCA Running and Multisport Coach

Like so many other things in the realm of human movement and nutrition, there is no one-size-fits-all.  This is very much true when it comes to exercise selection, be it for general strength and conditioning, or core strengthening.  Every human body is different and has a unique muscle balance/imbalance pattern and general compensation pattern.  Our bodies develop a certain way due to our specific training regimen and our various lifestyle activities.  Any type of repeated movement can create a specific pattern and in the case of athletes who train for specific disciplines, often one area of the body is much stronger than other areas.

There’s a great advantage to being aware of your own movement patterns but if you haven’t had a movement assessment done and therefore don’t know that about yourself, there are some predictable patterns to be aware of which can help you be a bit more selective with the types of exercises you perform.

In this article our focus will be on core exercises, which ones might be disadvantageous for most athletes due to fairly common muscle imbalances, and which ones are likely ideal for most athletes due to their promotion of hip and lumbar spine stabilization and balance.

What Comprises the Core

First, let’s take a quick look at which muscles make up the core.  Contrary to common assumption, the core is not just about the abdominal muscles.  According to The Brookbush Institute of Human Movement Science, “the ‘Core’ is comprised of all the muscles that cross the spine, pelvis and/or hips.”  This is otherwise known as the Lumbo Pelvic Hip Complex.  This includes the Rectus Abdominis (abs), Internal and External Obliques, Erector Spinae, Quadratus Lumborum, Transverse Abdominis, Multifidus, Latissimus Dorsi, Psoas, Iliacus, Rectus Femoris (middle quad), the Gluteus complex, Adductor Complex, Hamstring Complex and Tensor Fascia Latae, and well, there’s even a few more besides.

We can break things down a bit further by identifying the Internal and External Core.  The Internal Core (which is also referred to as the Intrinsic Stabilization Sub-system) is the complex of deep muscles that are primarily responsible for stabilizing the pelvis and spine but don’t really contribute to joint movement.  These muscles are the Transverse Abdominis, Internal Obliques, the muscles of the pelvic floor, the Diaphragm and the Multifidus.

The External Core is made up of the rest of the muscles on the list.  The muscles of the external core are primarily involved in various joint movements and secondarily contribute to stabilization of the pelvis and spine.

Whew!  Clearly there’s a lot to the core.  It’s not surprising that the Core of the Human Movement System is highly complex and is meant to be functionally balanced in order to encourage proper biomechanics and function of all moving parts.  It’s also not surprising to know that we can really mess things up.  Even the slightest bit of dysfunction in our movement patterns can lead to injury and pain so if we seek to be sound of body and perform optimally as athletes, we need to be knowledgeable and selective with how we train.

Does it matter which core exercises I choose to do?

Yes, it REALLY matters which core exercises you choose to do.  There are at least two considerations.

  1. We need to ensure that our Internal and External Core musculature remains balanced. In other words, it’s not advantageous to focus most of your core work on the external core muscles (easily identified as muscles that move our body) while doing little to no work on the Internal Core muscles.  If the External Core becomes stronger than the Internal Core, eventually those stronger muscles will become over-active and synergistically dominant and will begin to take over the role of stabilization.  As stated above, the primary role of the External Core is movement, not stabilization and they don’t do a great job at stabilizing.  So in the process of focusing on the external muscles, and let’s just be clear here, these are the muscles associated with aesthetics and are usually the ones targeted, you will destabilize your Lumbo Pelvic Hip Complex.  The Internal Core muscles will become less active.  Do not neglect your Internal Core.  Below, I’ll include a list of specific exercises, some labeled External, some labeled Internal, that all athletes should be doing.
  2. Most of the population deals with tight hip flexors and weak Gluteus muscles. In most people, it’s safe to assume this imbalance exists.  This has a lot to do with our common posture of sitting and staying in hip flexion for most hours of the day (and night).  This particular imbalance is responsible for countless hip and back issues and many movement related injuries that stem from this area.  Due to this common pattern, for most people, it is not advantageous to do Core exercises that also involve hip flexion to overcome the resistance of the move.  Hip flexors, most notably the Psoas and Iliacus, are responsible for bending forward at the hips.  So any movement that brings the body forward toward the legs or the legs up toward the body is hip flexion and the primary movers are the hip flexors, not the abdominal muscles.  Further developing strength in the hip flexors will be counter-productive to balanced movement.  Instead, in this particular case, the focus should be on strengthening the Gluteus muscles.  So to be clear here, there are many common core exercises that actually are counter-productive for many athletes.  Below, please find a list of core exercises to avoid (or do sparingly) if you have tight hip flexors.

Core Exercise Selection

Think for a moment about the type of core work you typically do.  Do you feel that based on the two considerations above, you might need to change some things?  Are you focusing only on core work that moves body parts (or external weight) and neglecting exercises that emphasize stabilization without movement (such as planks)?  Is your primary goal to build strong externally visible muscles?  Do you do any exercises that emphasize hip flexion (sit ups, hanging knee lifts)?

Here are some key take-away’s to ensure you have a sound core strengthening routine that will promote proper stabilization and muscular balance, and help keep you pain and injury free.

  1. Spend at least an equal amount of time working muscles of the Internal and External Core, and even consider focusing a slightly higher percentage of work on the Internal Core. Specific suggestions below.
  2. Avoid core work that involves active hip flexion as part of the resisted exercise.
  3. Remember the core is made up of many different muscles and include exercises that incorporate as many areas of the core as possible.
  4. As with all strength and conditioning training, perform exercises in all planes of motion, ie. Front, back, side and rotation.
  5. Make your primary goal to be stabilization and core balance rather than seeking some type of aesthetic improvement. The aesthetic aspect is much more about diet than it is about core exercise selection.
  6. Remember that the core is often involved in all forms of exercise and sports related activities and we are able to strengthen it functionally through exercises that are not specifically meant to isolate the core.  Whenever possible, challenge your core functionally and be sure you’re braced through your core during any type of exercise.

Here’s a List the Highest Recommended Core Exercises based on the considerations listed above:

External Core Focus:


Oblique Crunches (side crunches)

Reverse Crunches

Hip Bridges (from the floor)

Ball Bridges (shoulders on Swiss Ball)

Various Chop exercises

Ball Crunch

Ball Bridge with Trunk Rotation

Mountain Climbers and other types of plank position plyometric movements

Russian Twists

Resisted Oblique Twist


Internal Core Focus:

Planks of all types

Side Planks

Quadruped exercises (on all-fours)

High Plank with Shoulder taps

High Plank Anti-Rotation exercises


Exercises to Avoid (or do sparingly) due to high degree of hip flexion involved:

Hanging leg lifts

Hanging Oblique leg lifts

Hip Dip type exercises (such as side plank while dipping hip up and down)

Sit Ups

Leg lifts and variations (such as scissor kicks)



Holding legs up in isometric hold (such as 100’s)

If you use the above lists to help you select the best exercises for you and also continue to do functional training and conditioning, you’ll be doing a great job of promoting healthy and balanced strength and stabilization that will ultimately help you prevent pain and injury and improve your performance as an athlete.


About the Author: Cindy Abrami, BS Nutrition, NASM-CPT/CES, AFAA, Pn1 Nutrition Coach, UESCA Certified Running and Multisport Coach, Schwinn Certified Indoor Cycling Instructor

Cindy is a fitness and nutrition Professional, and elite level masters athlete with a passion to help her community find fullness of health and abundance of life through fitness and proper nutrition.  She is the owner of The Wellness Movement Santa Barbara.  Cindy is a competitive runner, duathlete and triathlete and holds national champion status as a masters runner and is the 2018 and 2019 ITU Sprint Duathlon World Champion (50-54).  She is currently working to become a Human Movement Specialist with a focus on injury prevention and is expanding The Wellness Movement USA into other communities.