My current intern and I recently had a young, 16 y/o female patient with a 3 year case of low back pain (yes, 3 yrs and just came to see us).  To make a long story short, after getting her symptoms calmed down (she had allodynia setting in to her low back), we started to perform more higher level activities as she is an all-state sprinter.  To find out, she could not hold herself up in a plank position to save her life!

We both were at awe of how “weak” her core was…especially considering she is an avid sprinter and recently competed in indoor track state finals.  So, I brought up this picture for my intern on McGill’s work on endurance norms for low back.

I am not a big advocate personally of simply looking at these norms to determine her level of performance, but I would like to see what others out there think.




  1. Hey Harrison,

    I love your blog and you insights on PT. Truly one of my favorite web resources.

    This post is a bit confusing to me, though. No offense intended, just to be clear.

    I am not sure what the data in the chart (McGill) has to do with core strength as I typically associate “core” with Transverse Abdominis and none of these values seem to directly represent core endurance. I guess a plank position, the way you tested your client, would be more specific to core endurance but I always refer to the ol’ BP cuff under the Lumbar curve in Supine while performing LE activities (Sahrmann), however, I rarely use this test as I feel it is not necessarily important.

    These 2 articles are helpful and cite some important literature in regard to this issue:

    From Part 2 in regard to the McGill study:
    “These maneuvers test the global
    musculature rather than the deep stabilizers. It has
    not yet been shown whether improvement in these
    tests correlates with symptomatic improvement or
    improved ability to stabilize the spine. However,
    they may be useful clinically in measuring progress
    in endurance and in motivating patients.”

    Part 2 goes on to say this in regard to another study involving adolescent participants:
    “researchers have found
    that decreased torso extensor endurance may assist
    in predicting those most at risk for future back

    And then this:
    “research has not yet proven that
    learning to isolate a contraction of the transversus
    volitionally carries over to automatic use of this
    muscle in daily tasks.”

    So it seems that general and unspecified global strengthening of abdominals and back extensors can be helpful in clients with LBP from the data referenced in these articles.

    In my clinical practice, I often feel it could be one of these “chicken or the egg” type situations, especially in the adolescent population. Were they weak to begin with or is their pain causing their weakness? In the end it doesn’t matter because both are typically present once they’ve made it to PT and both issues are feeding off of each other and causing further overload to soft tissue and joint structures in the Lumbar spine area with dynamic activities (sometimes even static activities, too).

    I do really enjoy the McKenzie Method, although I feel it does typically fall short in the athletic adolescent population because from my limited McKenzie exposure, strength is typically an afterthought in this approach. However it can be useful in assessing their response to repeated movements and symptoms during ROM testing. But in the end it all comes back to global Lumbar strengthening activities that progress to and are directly related to their specific athletic activity and training.

    I feel L-spine X-ray is always crucial in this population to rule out spondylolisthesis, pars defect or apophyseal injuries.

    Often rest from insulting activities is required, while making sure they stay motivated to maintain their cardio endurance through appropriate activities, until their strength is adequate to participate in higher-level tasks.

    Once again, I love your blog. Keep up the inspiring work!

    Joel A. Grace, PT, MPT

    1. Hey Joel,
      Thanks for the kind comments and overall for reading the blog.

      I agree that isolating the TrA with bloodpressure cuff and those approaches are becoming extinct. These norm values have to be expiring too…even though I really doubtful think many PTs use them clinically.

      I like utilizing MDT concepts too as it can give a high percentage relief but just like what you said, limited in all utility.

      I wish I could give a follow-up on this young lady to let everyone know how she did, but she had to stop therapy due to costs/insurance. I’ll have to do a phone follow-up sometime.

      Take care,

  2. sorry, are those numbers in seconds? as in a 185sec plank? that seems high. how is the plank standardized as to prevent a easily compensated movement.

    1. Jake,
      Yeh in seconds! But, not a plank. A flexion and extension hold (such as in a sit-up position for flexion and off plinth prone for extension). The side-planks though are what is standardized here…and yes the path of least resistance will set in.

  3. I think that my concern here would be in the applicability of the normative values: we’re using values gathered from apparently healthy populations and applying them to a patient/patient population experiencing pain (and in this case, clearly chronic pain with evidence of sensory alterations, implying CNS adaptations to chronic pain). Do we know what her values were like before her pain, or that if these values were below norms, this somehow had to do with her current pain experience now? I wouldn’t be concerned with this, honestly: the cause of her particular performance is unknown (initial strength deficit, current altered neuromuscular control in the presence of pain, strength decreases and muscle atrophy from potential avoidance, changes in movement in the presence of pain, altered recruitment in the presence of pain, etc, etc – or more likely all of these things?) and therefore the information might be valuable as a clinical indication of change from initial presentation, but we really can’t say much more than that, imo

    1. Hey Jonathan,
      Thanks for responding and I agree with what you are saying…especially the chicken/egg concept.

      In this particular case, I think this young girl always had poor core “performance” but has been an exceptional athlete possibly from simple athletic skill. I would think this would mean that the wiring is exceptional but she had such poor and altered neuromuscular control.

      We may not know the answers. I know from a treatment and assessment standpoint—-I don’t go with these values.

  4. Dear Harrison, I must agree that sometimes it can be a problem that most tests to determine a norm is done on normal individuals. However I consider this as my aim towards which I work with my patients to try and “normalize” them. If your patient is an athlete of high standards I think norms of “normal” healthy people should be your aim. I recently came across an article on abdominal muscle endurance testing ( J Strength Cond Res,2013. Jun 27(6):1602-1608) that I think can be of value to you. The researchers developed a flexion-rotation test to assess the oblique abdominal muscle endurance. In my opinion this is a more valuable test due to the functional application of the rotational component. Shouldn’t we as Physiotherapists work more towards functional abilities
    than testing in one plane?

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