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Challenging Core Stability: Unpacking the Myths and Misconceptions

Written by James Horner

Instagram @thenerdyphysio

A bit about me… promise I’ll keep it brief

  • I’m an MSK Physiotherapist working within the NHS in the UK. 
  • Since qualifying I have also worked part time in a number of sports, but mainly rugby. 
  • I’m a bit of a nerd… hence the instagram tag
  • The reason why I chose this topic was because I would say this was one of my first “mind blown” moments of my career. It shook some of my beliefs and started my pathway to becoming more of a critical thinker.
  • I don’t pretend to be an expert and my views are ones that have been moulded heavily by working with and listening to many different amazing people. (These views are also constantly evolving).

Hopefully that didn’t bore you too much! Lets get to the good stuff!

Firstly, what do we mean by “stability” ?!

“Give a small perturbation and observe the new behaviour. If the new behaviour is approximately the same as the old, qualitatively speaking, the system is stable.” Reeves et al 2007 

What does this mean?

Look at the bowls above with the balls inside (sorry art is not my strong point)

If you knocked these balls to the side they would roll back to the middle. This technically means they are stable.

However, …

You can clearly see that you could push the left sided one much harder before it came out of the bowl compared to the right which would come out quite easily. So although they are both stable, the left one is more “robust”.

So, do our patients need stabilising?

Many papers from the 90’s and early 2000’s quote something along the lines of “The osteo-ligamentus spine is inherently unstable and would buckle under 10kg of force”

This line of thought is used to push the narrative that we are unstable.

One problem though… we never forget to put our muscles on in the morning…

So how hard do our muscles have to work to “stabilise” the spine?Screenshot 2020-09-21 at 18.09.22.png

Cholewicki et al 1997

Loaded people with 30kg on their shoulders and measured muscle contraction needed to stay upright.

It was only between 2 and 5% of maximal contraction.

Not much strength needed there at all…

So, if it is not strength that is the issue…. is it muscle timing?

Hodges et al 1999 produced a pivotal paper which looked into the role of the transverse abdominus, which is often seen as the paper that pushed core exercises into the limelight. 

He found…. The Trans Abs often fires later in some people with back pain. 

  • Healthy people’s Trans Abs turn on prior to moving deltoid 
  • In SOME people with back pain it is delayed by 30-100milliseconds 

However,

  • A delay does not mean the spine is unstable
  • A delay does not mean the muscles did not switch on
  • A delay does not mean the muscles are weak
  • He also noticed the same delay with the hamstrings…(but we don’t see people trying to activate these before moving or tensing them when standing still…)

Also consider…Why would this cause pain?

Not convinced? What happens when we try and change the muscle timing?

Vasseijen et al 2012 – Put patients through a core exercise programme and although there were improvements pasted-image.tiffin pain scores they found no link between changes in muscle timing and improvement in symptoms….

This has also been shown in Mannion et al 2011

I am not saying core exercises do not help some people… but it is important to question our narratives around these treatments… Does it work the way that we think it works?

You may think this is just semantics… “It seems to work sometimes… I don’t care why it works”

….

Well you should care

  1. We can maximise the effects of our treatments better if we know why they work
  1. We have all seen the harm poor narratives can give patients, we need to improve our narratives to avoid this. Does an “unstable spine” or a spine that needs constantly bracing give our patients feelings of weakness and vulnerability… I would argue it does. 
  1. Finally the truth matters and has inherent value, even if the practical application is not immediately obvious. Knowledge is always powerful to us and our patients.

Some papers that provide food for thought…

B. Smith Et Al 2014 

  • The objective of this systematic review was to evaluate the current evidence for the benefit of stabilisation/core stability exercises for low back pain.
  • 29 studies included with over 2500 participants in total.
  • The results of this current systematic review suggest that stabilisation exercises improves low back pain symptoms, BUT they were found to be no more effective than any other form of active exercise in the long term. Furthermore, a trend of worse fear avoidance scores with programmes that only use core stability was noted.
  • “This review cannot recommend stabilisation exercises for low back pain in preference to other forms of general exercise, and further research is unlikely to considerably alter this conclusion.”

Perhaps the most definitive conclusion of any paper I’ve ever read!

Macedo et Al 2014 

  • Two-part study
  • First section was 172 participants doing graded activity vs core stability programme which found no difference between the two. 
  • Second section was a pre-planned post analysis of the data collected at 2,6 and 12 months. This showed there was a small sub section of patients who did respond better to core stability exercises… 
  • These were the patients who believed that their spine was unstable on questioning prior to the treatment.
  • Did the treatment just meet their expectations?

So why do core stability exercises “work”?

Are we just meeting patient’s expectations?

Is it habituation of certain movements?

Are we just load modifying through these exercises?

Unfortunately we simply don’t know the exact mechanism yet and these are just theories currently. 

To Conclude

As with many conditions, research shows us that the biomechanical explanations for an individual’s pain fall short under scrutiny. We are learning the pain experience is more complex than a minor timing issue and that the Bio and Psycho and Social all interact closely together. 

Core stability exercise can be appropriate for a certain subsection of patients, namely those who feel it will benefit them or enjoy that form of exercise. BUT, do not just limit yourself to this method of treatment as it has been shown general exercise can be just as effective. 

Thank you Thrive Physiotherapy Education Services, Liam and Matt, for hosting this blog, please check out the ThrivePES podcast for further great content and speakers! And thank you for reading.

James

References (in order of mention) and Further Reading

  • Cholewicki et al (1997); Stabilising Function Of Trunk Flexor-Extensor Muscles Around A Neutral Spine Posture, SPINE, Volume 22, Number 19, 2207-2212
  • Reeves et al (2007); Spine Stability: The Six Blind Men and The Elephant, Clinical Biomechanics , 266 – 274
  • Hodges et al (1999); Is There A Role For Transverse Abdominus In Lumbo-Pelvic Stability?, Manual Therapy, 74-86
  • Vasseijen et al (2012); Effect Of Core Stability Exercises On Feed-Forward Activation Of Deep Abdominal Muscles In Chronic Low Back Pain, SPINE, Volume 37, Number 13, 1101-1108
  • Mannion et al (2011); Spine Stabilisation Exercises In The Treatment Of Chronic Los Back Pain: A Good Clinical Outcome Is Not Associated With Improved Abdominal Muscle Function, SPINE, 1301 – 1310
  • Smith et al (2014); An Update Of Stabilisation Exercises For Low Back Pain: A Systematic Review With Meta-Analysis, BMC.
  • Macedo et al (2014); Predicting Response To Motor Control Exercises And Graded Activity For Patients With Low Back Pain: Preplanned Secondary Analysis of a Randomised Control Trial, Physical Therapy, Volume 94, Number 11, 1543- 1547

Other blogs I would recommend on this topic

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