So Called “Trunk Stabilization” Exercises are Anything But…

Trunk muscle stabilization training plus general exercise versus general exercise only: randomized controlled trial of patients with recurrent low back pain. Physical Therapy. 2005 Mar;85(3):209-25. Koumantakis GA1, Watson PJ, Oldham JA.

Abstract
BACKGROUND AND PURPOSE:
The purpose of this randomized controlled trial was to examine the usefulness of the addition of specific stabilization exercises to a general back and abdominal muscle exercise approach for patients with subacute or chronic nonspecific back pain by comparing a specific muscle stabilization-enhanced general exercise approach with a general exercise-only approach.

SUBJECTS:
Fifty-five patients with recurrent, nonspecific back pain (stabilization-enhanced exercise group: n=29, general exercise-only group: n=26) and no clinical signs suggesting spinal instability were recruited.

METHODS:
Both groups received an 8-week exercise intervention and written advice (The Back Book). Outcome was based on self-reported pain (Short-Form McGill Pain Questionnaire), disability (Roland-Morris Disability Questionnaire), and cognitive status (Pain Self-Efficacy Questionnaire, Tampa Scale of Kinesiophobia, Pain Locus of Control Scale) measured immediately before and after intervention and 3 months after the end of the intervention period.

RESULTS:
Outcome measures for both groups improved. Furthermore, self-reported disability improved more in the general exercise-only group immediately after intervention but not at the 3-month follow-up. There were generally no differences between the 2 exercise approaches for any of the other outcomes.

DISCUSSION AND CONCLUSION:
A general exercise program reduced disability in the short term to a greater extent than a stabilization-enhanced exercise approach in patients with recurrent nonspecific low back pain. Stabilization exercises do not appear to provide additional benefit to patients with subacute or chronic low back pain who have no clinical signs suggesting the presence of spinal instability.

My comments:

This is a great study on low back pain and exercise, all but killed by a bad title.  I have often seen it misquoted by researchers, physical therapists and physicians who are fans of the “biopsychosocial model” of treatment for low back pain.  The conclusion of the abstract doesn’t help either; both give the impression that exercises intended to strengthen or stabilize the spine are no more effective for reducing low back pain than general exercise. When I think of general exercise I think of treadmill, or recumbent cycling, or step aerobics, you know, general exercise.  I guess there is a lesson to be had here for people who read a study title, then skip to the abstract conclusion to draw their own conclusion.  That’s almost exactly what I do; I read the title, skip to the conclusion, to see if a study is interesting. I am glad in this case that I decided to send off for and read the entire paper, or else I would have missed what really happened.  In fact I read onward because I thought this study was going to refute one of the core tenants of my physical therapy treatment programs for low back pain, only to find that it supported it.  I think another lesson there is that you should always read opposing views to find out what you are missing, and I have learned a lot by doing so.

So what was this study really all about?  They compared two exercise programs performed twice weekly over 8 weeks.  The “general exercise” program wasn’t really general at all but was filled with a plethora of core (abdominal, low back, and hip) muscle strength and endurance exercises to include curl ups, planks, bridges, bird dogs, etc., all of which I would expect would do a great deal to “stabilize” the trunk.  The “trunk-stabilizing” group however included some of the above exercises but didn’t get to them until the last 3 weeks of the program. They first began with “abdominal hollowing” exercises intended to isolate the transverse abdominus. However, spine researcher Stuart McGill has shown it actually destabilizes the spine in comparison to abdominal bracing, which recruits all the core muscles at once.  Additional exercises (their exercise duration was twice as long) in the “trunk-stabilization” group were exercises attempting to isolate the multifidus, and then spine flexion/extension in sitting with an effort to literally aggravate low back pain.  This was so the patients could lose their fear of such aggravation.  The latter seems especially boneheaded to me, but apparently that’s the kind of treatment approaches one is left with once they have internalized the biopsychosocial model, ignore environmental factors, and treat low back pain as a psychological disorder rather than an anatomical one.

The results were that the “general exercise” group (which consisted of many exercises that in fact do stabilize the trunk/core) reduced low back disability faster than the “trunk-stabilization” group (which in fact contained very few exercises that increase true stabilization strength and endurance of the “trunk”).  The “trunk stabilization” group also had 2 subjects drop out due to increased pain with the exercise program, which I would speculate had a lot to do with the biopsychosocial model contribution to the program in which patients were instructed to work into painful motions such that they might be less fearful of them.

So I think a better title for this study is “So Called Trunk Stabilization Exercises are Anything But”. The terminology “trunk/core stabilization” in the low back therapy research really has been co-opted to mean transverse and multifidus muscle isolation, neither of which I think are very good ways to rehabilitate or stabilize the spine. In fact, this study showed they did nothing but delay functional improvements in those with low back pain in comparison to trunk strength/endurance exercise.

As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.

Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.

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