Core Stabilization (Part 1)

Dr. Blake Middleton Article, Blog Leave a Comment


“Core Strength”

We often hear, as triathletes, to keep our core strong. However, do you actually know what your core is and how to make it strong? We often hear to stand up straight, correct your bike posture and run form, do squats and other complex lifts, and maybe you even perform your daily 5 minute internet ab workout all to create a strong core.  Here I want to give you more than your “Do these X number of things for a perfect core” article and discuss what the core is, how it is used, and how to make it functional for you. Today’s article will focus on the former with a 2nd article to come with some actual “to-do” applications. Make sure you check out the end of this article to find a simple routine to assess your current core status.


By Jgcastor – Lumix Panasonic, CC BY-SA 3.0,

First off, I believe the terminology has been used incorrectly and therefore can confuse athletes on what they should be improving. For example, here is a short list I’ve seen used by others to describe core training:

  • Core Strengthening
  • Ab Work/Strengthening
  • Lumbar  stabilization
  • Dynamic Stabilization
  • Motor Control
  • Neuromuscular Training
  • Neutral Spine Control
  • Muscular Fusion
  • Trunk Stabilization

I know, it is head spinning, so here I will try to explain it to you as clearly as possible. I prefer core stabilization as it includes much more than strength. This refers to the ability to utilize strength along with endurance and motor control (activation and coordination) in a functional manner through all planes of motion and action. That is a lot and sounds pretty important.  This can be applied to a variety of situations you may currently be dealing with in your midsection. This includes preventative work, active rehab, and the eventual goal of performance enhancing.


Basics of “The Core”

Okay, I’ll admit it is not so basic but let’s try a little here. To think simply, let us try to relate core stabilization to the triathlete. This core is similar to the bike (work with me here). You have the fixed parts (bike frame) which consists of the bone and small ligaments. Then, the moving parts (chain, pedals, and wheels) similar to the muscles surround the core. Finally there is the control system (YOU, the athlete, pedaling or shifting gears) which is the nervous system sensing requirements of stabilization while planning strategies and sending these thoughts to the muscles. All 3 are necessary to interact as one unit for the best performance and stability. One system can compensate for deficits in another but only for a certain time.

We appear to have the most control over the moving parts of the core. To be brief, here are the muscle groups referred to as the “core” (I can send a full list of muscles if you’re curious). They include the abdominals in the front, paraspinals and gluteals in the back, the diaphragm as the roof, and finally the pelvic floor and hip girdle as the bottom. All these muscles have direct or indirect attachments in the low back connecting your arms and legs. These groups work together in one of two ways. 

The first way is as global muscles that are large and produce torque which provides general stabilization as well as movement. Many imbalances are seen in these muscle groups in low back pain. This includes delayed activation of the transverse abdominis (abs), imbalance in your oblique (side) muscles, asymmetry in hip extensor strength, and poor recruitment of the diaphragm and pelvic floor. Then there are local muscles which are smaller and connect directly to the low back providing stabilization at individual segments. These muscles are often shrunken or atrophied in athletes with low back pain.

Side Note: I dislike when people say their muscle “aren’t firing.” (usually athletes say their gluts) If this were the case they would fall right over. It’s actually that the muscles are not firing correctly and are out of sync or not firing to their full potential.

The control system has a complex job of maintaining stability by monitoring and adjusting the tension in the muscles. This process tells the muscles how to provide stability to the local muscles while allowing the global muscles to produce movement. As you can see, there is an important relationship between the systems that requires constant balancing and attention.

When balance is not achieved, instability is created. This can result from gross instability to the fixed parts (disk herniation). Otherwise it can be functional instability from poor muscle strength, endurance, or motor control. Often when we experience issues, there is some form of instability involving all 3 systems. Previously there has been a major emphasis on strengthening the global muscles when instability arises but now I hope you understand both global and local muscle groups along with each system needs attention to develop the core efficiently. Ultimately, it appears that muscle activation, coordination, and endurance may be more important than focusing solely on strength.


Assess Your Stability

So now you have the basics of what we are working on, let us look at a simple way to test your core stability. The following 4 tests will incorporate all of the above systems in order to find your weak points. Assess these by time to failure. It is important to have someone else monitor your positioning and assist as needed.

  • Plank: this assess the anterior and posterior muscles. Failure is when you lose neutral pelvis and the low back/buttocks fall down into a curve.
  • Lateral Plank: evaluates the lateral core muscles (oblique). Failure occurs with a loss of the straight line and the hips falling towards the ground.
  • Flexor Endurance Test: This test is a static crunch with hips and knees at 90 degrees (feet flat on floor and assistant holding ankles) while holding a crunch position at 60 degrees from floor. Failure occurs when the torso falls below the 60 degrees.
  • Extensor Endurance Test: perform by lying face down over a bench with the pelvis, hips, knee, and feet on the table (assistant holding ankles) and your upper body off the table attempting to hold the body in a straight line. Failure is when your upper body lowers to ground with flexion of your hips.

These tests were studied extensively by Dr. Stuart McGill who has dedicated his career to researching the core. He has published data for the time goals we should be achieving in these test:

  • Side Plank: 97 seconds (men) and 78 seconds (women)
  • Flexor Endurance: 136 seconds (men) and 134 seconds (women)
  • Extension Endurance: 161 seconds (men) and 185 seconds (women)

This is a quick routine that can be added into the schedule in addition to other fitness testing performed to evaluate gains in your swim, bike, and run.


How to Improve

In the next article, I’ll be less nerdy and provide some tips and exercises to improve your core stability. These will help you whether currently needing rehab or attempting to improve performance. For now, take the quick 4 position test detailed above and post results to the feed that linked you here. That will give you a starting point to reflect back on before starting a core stabilization focused routine.

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