The Core Stability Problem

When I refer to “Core Stability” I mean teaching patients isolated contractions of transverses abdominus and multifidus. This is then usually progressed (depending on the practitioner) to having the patient contracting these muscle in functional movement patterns. The end aim being reduction of pain and improvement in function.

From my perspective the “core stability” direction started following this sort of research:

Contraction of transversus abdominis was significantly delayed in patients with low back pain with all movements. Isolated differences were noted in the other muscles. The delayed onset of contraction of transversus abdominis indicates a deficit of motor control and is hypothesized to result in inefficient muscular stabilization of the spine. Hodges and Richardson (1997)

Trunk muscle activity occurring prior to activity of the prime mover of the limb was associated with hip movement in each direction. The transversus abdominis (TrA) muscle was invariably the first muscle that was active. Although reaction time for the TrA and oblique abdominal muscleswas consistent across movement directions, reaction time for the rectus abdominis and multifidus muscles varied with the direction of limb movement. Results suggest that the central nervous system deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipation of reactive forces produced by limb movement. The TrA and oblique abdominal muscles appear to contribute to a function not related to the direction of these forces. Hodges and Richardson (1997)

The common interpretation of this research being that:

These “core muscles” should be activating before the patient moves in order to “stabilise” the spine.

In back pain patients this is not happening therefore we need to teach these patients how to contract these muscles prior to movement.

Based on this research, and a lack of critical clinical reflection on my behalf, for a number of years I routinely gave everyone with chronic lower back pain (I even admit I did it as soon as possible in acute back pain as well!) an exercise program to improve the activation/function of their Transversus Abdominus and Multifidus. I even used a Real Time Ultrasound machine which enabled me to ensure patients learnt the “correct contractions”.

“The Problem”

The “problem” is see with “Core Stability” is that it still seems (here in my neck of the woods anyway) to be a standard “prescription” for most, if not all, patients with low back pain. I even get referrals for “Core Stability” training of patients with acute back pain! This is despite emerging research showing quite conflicting information compared to the initial research I outlined above. For example:

Patients with Chronic Low Back Pain (cLBP) did not show a delayed onset of feed-forward activation of the lateral abdominal muscles during rapid armmovements. Earlier activation was observed for one body side compared with the controls. However, the clinical relevance of this finding remains obscure, especially because there was no relationship between the onset of activation and any clinical parameters. Gubler et al (2010)

Abdominal muscle onset was largely unaffected by 8 weeks of exercises in chronic LBP patients. There was no association between change in onset and LBP. Large individual variations in activation pattern of the deep abdominal muscles may justify exploration of differential effects in subgroups of LBP. Vasseljen et al (2012)

In conclusion, the difference in group mean values for  Transversus Abdominus Contraction Ratio (TrA-CR) was small and of uncertain clinical relevance. Moreover, TrA-CR showed a poor ability to discriminate between control and cLBP subjects on an individual basis. We conclude that the TrA-CR during abdominal hollowing does not distinguish well between patients with chronic low back pain and healthy controls. Pulkovski et al (2012)

Neither baseline lateral abdominal muscle function nor its improvement after a programme of stabilisation exercises was a statistical predictor of a good clinical outcome. It is hence difficult to attribute the therapeutic result to any specific effects of the exercises on these trunk muscles. The association between changes in catastrophising and outcome serves to encourage further investigation on larger groups of patients to clarify whether stabilisation exercises have some sort of “central” effect, unrelated to abdominal muscle function per se. Mannion et al (2012)

We explored the cross-sectional relationships between lumbar multifidus (LM) intramuscular adipose tissue (IMAT) infiltration and low back pain (LBP) at 3 successive time points and investigated the role of IMAT in predicting the occurrence of LBP after 5 and 9 years………..There were no consistent cross-sectional associations between LBP/leg pain and LM IMAT at 45 or 49 years of age and LM IMAT did not predict future LBP or leg pain. The relationship between LM IMAT and LBP/leg pain is inconsistent and may be modified by age. Hebert et al (2014)

The quantity and quality of literature on the use of core stability exercises for treating LBP in athletes is low. The existing evidence has been conducted on small and heterogeneous study populations using interventions that vary drastically with only mixed results and short-term follow-up. This precludes the formulation of strong conclusions, and additional high quality research is clearly needed. Stuber et al (2014)

This systematic review highlighted that changes in morphometry or activation of transversus abdominis following conservative treatments tend not to be associated with the corresponding changes in clinical outcomes. The relation between post-treatment changes in characteristics of lumbar multifidus and clinical improvements remains uncertain. Wong et al (2014)

My Thoughts?

I am sure some of you can dig me up research that shows that core stability training does work. That’s fine. You will get no argument from me if you show me a patient that, when contracting their “core”, has significantly lessened pain in their functional activities and/or is progressing and improving well with a “core stability” program. Although I might debate with you the merits of what the “contraction” is actually doing based on the research I listed above!

The problem I have is when I hear that every patient with low back pain needs to have their “core stability” assessed and trained. I see far too many examples of patients (what Dankaerts et al might call an Active Extensor Pattern) who exhibit many of the following characteristics:

1. Very upright postures with excessive muscle bracing/guarding of their trunk muscles (picture someone holding themselves in a rigid lumbar lordosis).
2. Note a reduction in pain when they do activities or undertake treatment that “relaxes” their trunk. For example:
   1. Gentle cardiovascular exercise.
   2. Stretch their lumbar/hip area.
   3. Have some soft tissue/manual therapy to their lumbar area.
   4. Relax their trunk muscles (consciously soften their posture and/or do some diaphragmatic/belly breathing).
   5. Put some heat modality on their painful area.
   6. Float around and do some exercise in a hydrotherapy pool.
3. Worsen when they contract their transverses abdominus and/or multifidus. Before you say they are probably not contracting correctly I have often checked if they are contracting correctly using Real Time Ultrasound……they are……and yes it worsens their pain.
4. Gain sustained improvements when they learn to relax their trunk (reduce muscle guarding and bracing) and incorporate this postural pattern into functional activities.

I hope nobody is going to argue with me that this type of patient needs to improve their “core stability”!? 🙂

Surely we can also hopefully see that not every patient needs to improve their “core stability”.

My Advice

1. Don’t blindly proceed down a “core stability” path will all back pain patients. The evidence doesn’t support it for all patients. If you do proceed with it then make sure that the patients ability to contract the “core muscles” actually improves their pain in provocative activities/movements. Look for some “proof”!

2. Have a look at how your patient moves and the postures they hold. If they look like they are holding themselves rigidly see what happens to their pain if you can facilitate some relaxation of their trunk. If this helps then encourage strategies to reduce the rigidity/bracing (soft postures/diaphragmatic breathing) and incorporate this into rehabilitation programs to retrain movement patterns. You can still put these patients into the gym or onto pilates reformers, they just need to focus on soft/relaxed postures etc whilst doing their exercises.

3. Ask and listen to what aggravates and eases their pain. Some patients will tell you that contracting their “core” makes their pain worse (even when they are contracting “correctly”). They might also give a consistent message that activities that ease their pain are related to relaxation and/or gentle movement of their trunk and surrounding muscles.

4. Screen for poor prognostic indicators and beliefs. Without doubt the most beneficial “shift” in my clinical practice has revolved around:

• Screening patients for poor prognostic indicators (see my other blog posts here, here, here and here for more information on this topic). Please note that “core stability” weakness as far as I am aware is not a recognised poor prognostic indicator.
• Asking them in relation to what their beliefs and understandings are in relation to the cause of their pain and why they are not getting better. This can be enlightening. Often the resultant information relates to incorrect beliefs regarding what their imaging results show (see here and here) and subsequent misconceptions regarding what they must do to stop their back getting worse. For example they have significant fear relating to “having a disc bulge that might slip/bulge further if I bend” and believe they have to “brace their spine and avoid bending their back to prevent this happening”. Incorporating education regarding their faulty beliefs is often critical to enable them to have the confidence to relax their trunk and minimise the guarding.

5. Explain to them and educate them the about all of the above! Bearing in mind you may have to repeat it a number of times and “chip” away at it for a number of sessions if their beliefs and understandings are entrenched.

Thanks for reading.