{"id":2058,"date":"2020-08-01T09:50:30","date_gmt":"2020-08-01T07:50:30","guid":{"rendered":"https:\/\/www.physiotutors.com\/?p=2058"},"modified":"2023-03-27T17:41:35","modified_gmt":"2023-03-27T15:41:35","slug":"the-myth-of-core-stability","status":"publish","type":"post","link":"https:\/\/www.physiotutors.com\/the-myth-of-core-stability\/","title":{"rendered":"The Myth of Core Stability – Stop blaming a weak core for low back pain"},"content":{"rendered":"\n

The myth of core stability: In this blog article you will learn why we need to stop blaming a weak or “unstable” core for low back pain and why the whole idea of a weak or “unstable” core is based on outdated research ideas.<\/p>\n\n\n\n

\u201cYeah, you have a weak core, you gotta do core stability exercises man\u201d. If we had received one cent per time that a weak or unstable core had been blamed for a patient’s low back pain in the health or fitness industry, we would surely be millionaires by now. In this blog, we will have a look back in time to see where the idea of an unstable core came from and discuss why the concept is BS.<\/a><\/p>\n\n\n\n

\"Hodges
Hodges et al. (1996) Interestingly, the onset of the Multifidi (MF) do not seem to differ in this study<\/figcaption><\/figure>\n\n\n\n

Almost 25 years ago, Hodges et al.<\/a> conducted a study in which they found a delayed onset of contraction of the transverse abdominis of 50 milliseconds when patients with chronic low back pain raised their contralateral arm compared to a healthy group.
This paper has triggered the core stabilization craze that we are still seeing in the health industry today. In short, the concept was born that the deep stabilizers, namely the transverse abdominis and the multifidi would act as a corset to stabilize the lumbar segments around mid-range, which was termed \u201eneutral zone\u201c. In 2008, however, a study by Alisson et al.<\/a> measured the transverse abdominis bilaterally and found that both sides act independently. So the left side contracts when you raise your right arm and the other way round. They concluded that the TrA does not act as a corset and that the idea of the muscle as a bilateral stabilizer needs to be revised.<\/p>\n\n\n

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Both sides of the TrA act independently, thereby questioning the concept of a “corset function”<\/span><\/p>\n <\/div>\n

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Assessment<\/strong><\/h2>\n\n\n\n
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Anyways, let\u2019s assume that the function of the TrA is still that of a stabilizer of the lumbar spine. While this delayed muscle onset was measured in a laboratory setting, we will have to ask ourselves if we can detect this \u201edysfunction\u201c in the clinic. In practice, the pressure biofeedback unit was invented to determine the function of the TrA and multifidi. But how accurate is this measure really? Lima et al. In the year 2012 compared the validity of the pressure biofeedback unit to electromyography and found a very poor diagnostic accuracy with both sensitivity and specificity of 60% – and then we are not talking about the delayed onset of contraction, but just A contraction of the muscles.<\/p>\n\n\n

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The pressure biofeedback unit is not a valid tool to assess TrA and multifidi function<\/span><\/p>\n <\/div>\n

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What about movement control tests? Luomajoki et al. (2007)<\/a> showed that a test battery of 6 different tests had substantial intra- and inter-rater reliability. If you\u2019re curious about the battery, check out the video in the top right corner. While these tests are reliable, we don\u2019t know if they are also valid: In other words, how do patients with low back pain perform these tests compared to subjects without pain? And even if there was a marked difference between groups, how do we know if those movement \u201cflaws\u201d are relevant to the persistence of back pain?
We know that people move differently in pain and it could very well be that this altered movement strategy is an effect rather than the cause of pain.<\/p>\n\n\n\n

Treatment<\/strong><\/h2>\n\n\n\n
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But let\u2019s continue and assume that the TrA has an important stabilizing function and that we can accurately detect patients with a delayed onset of contraction in the TrA and multifidi. What then happened in practice is that we started to perform training for those muscles in either supine or four-point kneeling position. But how is strength training gonna fix the timing issue?\u00a0Lederman in 2008<\/a>\u00a0compares that to trying to play to piano faster by exercising with finger weights and performing push-ups. On top of that, how is being able to perform a draw-in maneuver in a supine position going to carry over to activities of daily living? The idea to train those muscles in a supine or kneeling position with slow speed contradicts the principle of specificity and similarity or transfer. The only thing that would make sense is to train the speed of movement and hope that the system will somehow reset itself.<\/p>\n\n\n\n

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To overcome this issue, proponents of core stability came up with the solution to teach everyone to continuously brace their cores in order not to have to worry about onset timing. This proposal is completely abnormal and not how our nervous system works. Show me one patient who is consciously co-contracting voluntarily all the time \u2013 it\u2019s not possible because our nervous system wants to perform a task and then organizes muscle activity to achieve that task and not the other way round. This is like driving in reverse all the time. That\u2019s the same reason why most patients have such difficulty performing a proper draw-in maneuver. Not sure if you are like me, but I always hated to give this exercise to patients because I knew it would be super weird and over-complicated to explain this exercise to patients and they would often not be able to do it even if I tried with different cues or the pressure biofeedback unit.<\/p>\n\n\n\n

At last, we\u2019d like to add that increased co-contraction of the trunk muscles happens involuntarily in a lot of patients with low back pain. The low back pain researcher Kjartan Vibe Fersum said the following (and we stole this from Jarod Hall\u2019s lecture on the topic by the way) \u201eIf people in pain walk like a plank, maybe don\u2019t put them in a plank\u201c.<\/p>\n\n\n

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If people in pain walk like a plank, maybe don’t put them in a plank – Kjartan Vibe Fersum, Back pain researcher<\/span><\/p>\n <\/div>\n

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To make the story short, research has then also shown that training does not improve feed-forward activation of deep abdominal muscles (Vasseljen et al. 2012<\/a>, Allison et al. 2012)<\/p>\n\n\n\n

Okay, so now let\u2019s say that unless all that we\u2019ve stated earlier, we would be able to change the onset timing of the TrA and multifidi \u2013 does it even matter?
Credits to Jarod Hall again for assembling the following list of studies who have shown that:<\/p>\n\n\n\n