August 10, 2010 
In a recent post I argued that there exists very little scientific evidence to justify the ubiquitous recommendation that core strengthening is a good way to prevent and/or cure low back pain. In fact, there is significant evidence that core work is no better than general exercise for these purposes. Some recent studies have provided even more support for this point of view.
In the July 2010 issue of Physical Therapy, a paper by Unsgaard-Tøndel discussed a study where a hundred participants with back pain worked for eight weeks with physical therapists. One group did core strengthening, another did core coordination, and another just did general exercise. Each group had the same results immediately and one year after treatment.
In another study widely reported in the media, 1,100 soldiers were divided into two groups during training – one did specific forms of core training exercises, and the other did plain old- fashioned sit ups. Again there were no differences between the two groups in terms of pain and injury. Although some people will point out that sit ups are in fact a core training exercise, this study helps dispel the commonly held idea that core strength exercise must be done in a particular manner in order to be effective, such as making sure to draw in the abs, or brace the abs, or whatever.
These papers provide further clues that we should stop looking for pain in terms of poor body mechanics. Instead, a better target would be the nervous system, which processes and controls pain. Here are some posts on how that process works and what can be done with that information.
Thanks to Paul for pointing out the new studies.
Better Movement 
Is it important that different muscles are equally strong? Cause I’m wondering if it’s bad to do push ups every other day or so and no other specific strength training. Would this cause muscle imbalances (whatever that means) and could this be problematic? I would hope that the brain is smart enough to know about the strength of the muscles and smart enough to give different orders to different muscles depending on their capacity. If this would be true having some strong muscles and some not so strong would not be a problem.
Tim,
Interesting question. My GUESS is that, in general, changes in structure such as more musculature, stronger and tighter tendons will create mechanical changes in the body that the brain is not accustomed to, which might require some adjustment. An analogy might be changing your running shoes or ski boots. At first they will feel a little different and there may be decreases in performance or even “blisters.” But once you get used to the new structure, the shoes feel natural. If you change the body’s structure in an unbalanced way, this would probably create even a greater period of adjustment, and maybe the shoes will never be a good fit. That being said, I really doubt that pushups every other day would likely create strength imbalances sufficient to cause pain or problems. Maybe something like heavy benching while never doing back work could create a problem.
I agree with you regarding “core” exercises helping back pain. I have always considered the notion that back pain was due to some sort of “weakness” suspect. That is not to say that weakness doesn’t play a part. However, I have always found with my patients that stretching does more to relieve back pain than “strengthening” exercises.
There are pieces of evidence against, but I haven’t given up on core exercises entirely!
Deep core muscle such as Transversus Abdominis show consistent inhibition and delay in back pain patients [1] as well as in those with induced back pain [2].
Specific retraining exercises can be effective at long term reversal of these changes [3] and sit ups alone don’t seem to have this effect [4].
There seldom never silver bullets with musculoskeletal conditions, but the evidence is mounting for this kind of specific retraining being important in returning to full function. Also, it adds information on why sit ups seem to be no better than general exercise.
[1]Hodges PW, et.al. J Spinal Disord 1998;11:46-56
[2]Hodges PW, et.al. Exp Brain Res 2003;151:262-271.
[3]Tsao H, et.al. Journal of Electromyography and Kinesiology 2008;18: 559–567
[4]Tsao H, et.al. 14th Biennial conference of musculoskeletal physiotherapy, Brisbane,
Australia; 2005.
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