Evan Osar: Low Back Pain – The Myth of The Weak Core – Part 1

Low Back Pain
Your client, Sheila, a healthy 38-year-old single professional, has been mentioning to you that she has had low back pain for the past few weeks. Up to this point, she was still making her regular training appointments, but she is now beginning to cancel and miss sessions due to her chronic discomfort.

You evaluate Sheila’s program and feel you have been doing a good job working her through a corrective and progressive core strengthening program. You have also been paying attention to her posture and giving her home correctives, including stretching and strengthening exercises. Not knowing what else to do with her, you refer Sheila to her physiotherapist.

Sheila emails you an update: her physiotherapist informed her that she has a weak core and needs to do more core strengthening exercises. While you feel like her program has a strong core foundation to it, you begin incorporating more planks, chops, and kettlebell carries to her program.

After several weeks Sheila is still experiencing low back discomfort, leaving you both frustrated and confused.

It is often believed that structural or mechanical low back pain (LBP)—low back pain stemming from a structural/mechanical cause such as injury or trauma to the disc, joint, ligament, muscle, or fascia—is related to a weakness within the core. Early in my career, I unfortunately perpetuated this industry-wide myth when I often wrote and lectured about the ‘weak’ core and its contribution to LBP.

In this article, I am going to discuss the myth of the weak core and introduce the idea that structural/mechanical LBP has more to do with an individual’s core stabilization strategy rather than their overall core strength. I will also introduce an easy to implement assessment that will enable you to determine, with good accuracy, whether or not your client’s low back issues stem from a strength deficit or rather from a non-optimal core stabilization strategy.

A follow-up article will discuss how to use corrective exercise to improve your client’s core stabilization strategy.

weak core, low back pain

The Myth of the Weak Core
The myth of the weak core has been perpetuated for as long as the topic of the core has been discussed. There are indeed some individuals who I would consider to have core weakness. I have worked with many individuals, diagnosed with multiple sclerosis, Parkinson’s and other neuropathologies, who do indeed demonstrate core weakness. Some inactive seniors and individuals who have been bedridden may demonstrate a certain level of core weakness as well. Rarely do I see individuals without a true underlying neurological cause walk into my clinic with what I would consider core weakness. To the contrary I believe that many of these individuals are experiencing the ramifications of a non-optimal core stabilization strategy rather than core ‘weakness.’

As previously mentioned, early in my career, I too thought that a weak core contributed to the LBP of my patients. However, after successfully helping my patients and clients achieve a stronger core, I didn’t notice an appreciable change in the incidence of LBP in my practice.

In my early career, I would see mostly sedentary individuals presenting with LBP. Later, I began seeing more active and relatively healthy individuals coming into my clinic with LBP. Interestingly, the majority of them were doing regular core strengthening programs.

After treating thousands of individuals with LBP in my clinic, I began to wonder if they really were experiencing symptoms related to core weakness. I identified several inherent problems with the concept that a weak core was contributing to my client’s LBP. I began to focus on three significant issues within the idea of the weak core and its contribution to LBP.

  1. If a weak core is truly the problem, how were some of my strongest patients—for example, one individual who could squat 700 pounds and plank for two minutes straight—having back pain? And how was he able to work out without experiencing low back pain but experienced pain when he was sitting, standing, and bending over? Why are our health clubs full of relatively strong individuals who experience chronic low back tightness and discomfort? Why were many of the strongest collegiate and professional athletes I was treating (many of whom were not involved in contact sports) experiencing low back pain?
  1. As an industry, how are we determining whether or not our patients and clients have a weak core? While I used specific muscle testing adapted from Applied and Clinical Kinesiology in my office, I was consistently finding individuals whose core muscles tested strong during isolated muscle tests, yet they still had low back pain. Additionally, many of these individuals could easily pass core strength/endurance tests, such as the prone bridge (plank) and lateral musculature test, yet struggled to maintain ideal postural alignment during a bodyweight squat, a quadruped reach and traditional hip bridge assessments. Similarly, many of these same individuals could successfully squat significant amounts of weight, but could not maintain optimal trunk, spine, and pelvis alignment when they were simply asked to sit in a chair or perform a push up with optimal core control—even when performed on an incline surface.
  1. If core weakness is truly contributing to individual’s low back pain, why were so few of my patients not resolving their symptoms after undergoing a progressive core strengthening program? And why don’t individuals who appear relatively frail and weak experience low back pain? Shouldn’t they be experiencing low back pain and dysfunction related to core weakness?

The lack of viable answers to these questions was eventually the springboard for my journey into understanding why so many of my clients experienced LBP.

It was after many years of studying and truly looking at how my clients were moving that the reasons for structural low back pain started becoming clear. When I began watching how these individuals moved, I noticed fairly common traits in individuals that were experiencing LBP.

I noted that individuals with chronic LBP:

  • Demonstrated a tendency to brace or hold their abdominal wall tight even in quiet standing and sitting. (The core muscles should be relatively relaxed in positions such as quiet standing and sitting.)
  • Tended to over-brace and even perform a Valsalva’s or bearing down when they would perform even simple core exercises like marching leg lifts. (The abdominal wall should be active but not locked and braced under low level core exercises.) Many of them demonstrated a diastasis recti with an umbilical herniation during their core exercise.
  • Would default to pulling their pelvis into a posterior tilt and the lumbar spine into flexion to stabilize their core during many core assessments and exercises. (The trunk, spine, and pelvis should remain relatively neutral during many core exercise unless specifically testing training spinal flexion.)
  • Performed well during higher-level tasks such as planks or loaded squats but struggled to perform lower-level tasks such as lifting their feet off the table from a hook lying position or performing a bodyweight squat.
  • Demonstrated a poor respiratory pattern with a tendency to be predominately abdominal breathers with little contribution from their thorax (there should be three-dimensional breathing including movement of thorax when observing quiet respiration)

Unfortunately, very few of the core assessments I was performing at the time were actually looking at the strategy (how the nervous system coordinates posture, muscle activation, respiration, etc. to produce efficient movement) the individual was using to complete the task. This suggests that the majority of these tests were actually functioning more as a screen rather than a true assessment: many individuals were passing the tests although they were doing so with a compromised strategy. In other words, the individual had the muscular strength or endurance to complete the task—for example, hold the prone bridge (plank) position for a period of time. However, they were utilizing a non-optimal strategy (for example, moving into posterior pelvic tilt and lumbar spine flexion or compromising their breathing) when performing the test.

These findings led me to develop a series of assessments that focused more on the quality of the movement during the test rather than whether or not the individual could complete the test. The benefit of this type of interpretation is that it provides the tester with information about the individual’s strategy for stabilization and movement rather than simply evaluating whether or not they have the ability, strength and/or endurance to complete the task.

The Wall Lift Off Test
Although this test will actually be challenging for most individuals to perform, I consider the Wall Lift Off Test (WLOT) a relatively a low-level core assessment. In comparison, the Prone Bridge Test (holding a plank position for time) or an Overhead Squat are much higher-level assessments because they require a significantly higher level of core activity and coordination. I have found that lower-level tests such as the WLOT provide more accurate information as to an individual’s strategy because they will highlight how the individual is performing what should be a relatively easy task to complete. It is generally easier for the individual to compensate by bracing their core and, in essence hide their compensations when performing a higher-level test such as the Prone Bridge Test than during lower level assessments.

This test has demonstrated excellent reliability across a wide range of populations from sedentary to extremely athletic individuals. Even ‘strong’ individuals will have a hard time beating this test because the tester will be observing the strategy for lifting the legs versus whether or not the individual is able to complete the task.


  • The individual lies on their back with their feet on the wall about hip width apart. You can also begin the test from the hook lying position if a wall is not convenient.
  • The individual should be relaxed and positioned in as much of a neutral position as possible. Their trunk, spine, and pelvis should be in a relative neutral position—feel free to place a towel or bolster under their head to position the head and neck in a more ideal position. Note: don’t force the individual into a certain posture—allow them to lie in a relaxed position.
  • Instruct the individual to lift one leg off the wall so that their hip and knee are each flexed to 90°. Note what happens to their alignment, breathing and abdominal wall during the lift.
  • Then, ask them to lift their second leg off the wall and again take note to what happens to the aforementioned regions. They only need to hold their legs in this position for a maximum of 10 seconds.
  • Instruct the individual to return their legs one at a time to the wall while observing the strategy they use to bring their legs back down to the wall.
  • Once you have performed the above test, instruct the individual to activate or brace their core and repeat the test comparing this method to their previous method. Note whether or not it changes their strategy. If the individual has an optimal core stabilization strategy, activating their core should help them perform the test without changing their alignment, ability to breathe, or have a conversation with you with their legs in the elevated position.


Wall Lift Off Test: Start (left); Finish (right).
There should be no change in alignment or ability to breathe during the test.

Optimal core stabilization strategy (left); non-optimal (right):
Note the abdominal distension that occurs with the lifting of the legs
when there is a non-optimal core stabilization strategy.

With an optimal core stabilization strategy, the individual should be able to lift both legs off the wall while maintaining:
Their alignment (no rotation, extension or flexion of the spine or pelvis),
Tone of their abdominal wall (no distension), and
An optimal diaphragmatic breathing pattern.
Additionally, they should be able to have a conversation with you while in this position indicating they are not holding their breath or bearing down (Valsalva’s) during the assessment.

Common signs indicating a non-optimal core stabilization strategy include:

  • Inability to hold the test position
    • It is common to see spine and/or pelvic rotation as soon as one leg is lifted off the wall and when both legs are lifted, extension at the thoracolumbar junction, suboccipital extension, protraction of the shoulders, and/or the body being pulled towards the feet, especially as the second leg is lifted off the wall.
  • Abdominal distension as the legs are lifted
    • This suggests that the individual is using a Valsalva’s or bearing down to stabilize their core under the load of their legs. There should be no downward displaced pressure with optimal core stabilization.
  • Excessive trunk shaking while holding the legs elevated
    • This indicates there is an incoordination of the core musculature and the nervous system is over-utilizing muscular contraction for stabilization.
  • Breath holding and/or inability to have a short conversation while legs are elevated
    • This is also an indication that the individual is using a non-optimal strategy—generally over-activation of the abdominal wall and breath holding—for control. In many of your older clients you will notice hyperthermia (their face will turn flush) because they are holding their breath and/or bearing down during the test.
  • Low back pain when lifting their legs up and/or holding their legs off the wall

Here’s a video demonstration of the test:

If the individual can hold both their legs up and off the wall, this indicates to you that their core is strong enough to support the weight of their legs. Inability to maintain optimal alignment and breathing during the WLOT is rarely an issue related to not having enough core strength. If the individual demonstrates any of the above signs, this indicates that their low back issue is more likely stemming from a non-optimal core stabilization strategy rather than having a strength or endurance deficit.

Although every test has its own set of inherent flaws, I believe that the Wall Lift Off Test can be a very valuable part of determining an individual’s core stabilization strategy. While one assessment alone is rarely enough to determine the full extent of someone’s core stabilization strategy, I have found that the Wall Lift Off Test provides sufficient information about whether or not clients have a strength or a strategy issue. It is important to note that this test should not be the only test that is performed to determine an individual’s core stabilization strategy. However, the findings of this test should help identify some of the individual’s non-optimal core stabilization strategy that can guide you during additional tests.

Once you’ve identified that the individual has a non-optimal core stabilization strategy, the program goal needs to focus on helping them develop a more optimal strategy. Strength should only be developed on top of an optimal strategy or the individual will simply be creating a more significant issue.

The best, or rather, most effective core exercises are the ones that enable the individual to maintain optimal alignment, three-dimensional breathing and myofascial control throughout the pattern. The exercises being used are less important than the strategy the individual is utilizing to perform those exercises. Choose exercises that allow your client to successfully align, breathe, and control and you have given them the framework for developing and maintaining an optimal strategy. I will discuss this concept further in part II of this article.

Is this differentiation between strength and strategy important or is it simply a semantics argument?

I believe it is important to differentiate between strength and strategy as a contribution to structural LBP because if strength is developed on top of a non-optimal strategy, any deficiencies become exaggerated—ultimately setting the individual up for greater issues. Additionally, if a patient or client is told they have a weakness they will likely undertake a core strengthening program with very little chance for improving their core stabilization strategy, which is the most common reason they developed structural/mechanical LBP. Conversely, if the individual develops a more optimal core stabilization strategy then they will have created a foundation for success and any additional strength gains will enhance rather than detract from their performance.

Structural/mechanical low back pain is a common issue affecting much of our population. Many individuals suffering from low back pain are identified as having a weak core and therefore instructed to undertake a core strengthening program. This article has discussed the challenges of the notion that a weak core contributes to structural low back pain. As part of a comprehensive assessment, the Wall Lift Off Test provides a method for differentiating between an individual’s core strength and their core stabilization strategy as a contributor to their low back pain. Several common signs were discussed for identifying when an individual demonstrates non-optimal core stabilization.

If the individual demonstrates any of the aforementioned signs, then the primary rehabilitation or training goal becomes to help them develop a more optimal core stabilization strategy. In part 2 of this article series, I will discuss and provide examples of how you can help your clients or patients develop a more optimal strategy while safely and effectively strengthening their core.

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