// Perfect Practice - Rigidity does not equal stability - improving our understanding of core control

by Lisa Champion

At the recent Australian Physiotherapy Conference in Cairns (October 2007) several noted researchers sought to try and clear up some of the confusion and misconceptions surrounding the core stability debate (to brace or not to brace). The big take-home message was – don’t think that making the torso rigid is necessarily making it stable. Rigidity is not to be confused with core stability for two reasons. Firstly, co-contracting the global muscles to stiffen the torso can have adverse effects on movement.

And secondly, the co-contraction strategy seems to be contributing to a whole new sub-group of people with back pain. Let’s take a look at the finer details of these two points and then discuss some ideas that we can implement in our training programs to ensure that we aren’t falling into the ‘rigid = stable’ trap.

Effects of the ‘stiffening strategy’ on movement

Co-contracting the global muscles of the trunk with the spine in neutral can be an effective strategy for protecting the spine when a) the load is high1,2 (i.e., heavy lifting) and b) the load is unpredictable3 (i.e., lifting an unknown weight). So, it’s fair to say that in these circumstances the co-contraction strategy can work to protect the spine, but may not stabilise the spine appropriately.

Too much spine stiffening can:

  • increase joint loading which may lead to accelerated changes in spinal pathology
  • reduce movement which is important for the dissipation of forces
  • decrease balance
  • adversely affect breathing patterns
  • increase urinary incontinence
  • increase risk of falling.
University of Queensland researcher, Dr Paul Hodges, suggested that rather than thinking of maximising stability, we think of optimising stability. Optimal stability is dynamic; a balance between movement demands and stability demands, and to achieve it we may need to increase or decrease muscle activity. Complex strategies are needed for optimal dynamic control ranging from co-contraction to finely tuned bursts of muscle activity. And, the strategy we use depends on two things; the requirements of the task and the abilities of the individual. We can’t just think that co-contracting or ‘bracing the abdominals’ is the answer to every movement need.

Co-contraction strategies

Interestingly, when people with a history of back pain use the strategy of ‘augmenting’ or ‘switching on’ global muscles to increase stability (whether done consciously or unconsciously) the augmentation is considered a factor in the persistence and/or recurrence of back pain.6 This may occur as a result of the above listed factors, such as increase in joint loading and poor dissipation of forces. Augmentation often becomes an automatic response in back pain sufferers. It has been suggested that in many people (but not all) the central nervous system appears to adapt to pain by increasing the muscle activity to protect the back.

This could occur as a compensation for structural insufficiencies (i.e., bones that are not aligned properly and ligaments that are weak and/or stretched), inaccurate proprioception (which commonly occurs in the presence of pain and/or injury), to prevent further injury and to prevent further pain.8

Dr Peter O’Sullivan from Curtin University in WA is not only a leading researcher in the field of back pain, but also works in private physiotherapy practice enabling him to stay at the forefront of both research and practice.

He commented that he was seeing a whole new sub-group of patients with back pain who were using the co-contraction strategy when moving. He said that a common signature in patients with lower back pain was a lack of ability to relax as they sit or flex forward.

The question was presented: why do people develop adaptive behaviours that are actually provoking their pain?

He suggested that what starts as a ‘protective response’ ends up becoming habitual. The habitual augmentation then sets off the chain of reactions that leads to more pain.

An example would be if you were to touch a hot plate with your finger. You would immediately recoil your hand and the hand would stiffen in response to the pain. However, once the pain went away you would relax your hand.

With back pain, though, there seems to be a certain percentage of people whose systems don’t know to revert to normal, so they keep the spasmy ‘initial’ response and can’t turn it off.

Dr O’Sullivan also commented that many of the people presenting with habitual co-contraction were coming from strong fitness and Pilates backgrounds. Could the fitness industry’s buzz words ‘brace your abdominals’ be contributing to people developing back pain? It’s most certainly food for thought.

If we are training clients that have back pain, then we should be aware of these potential issues and if necessary work towards helping them overcome the bracing habit. We should teach clients to use a variety of movement strategies through various ranges and positions, not just stiffening a neutral spine through every movement. This can only be done by encouraging a new motor response for low and medium level tasks that does not involve ‘bracing’.

Consider this comment from a client of mine (an elite kayaker) who has had a history of back pain and had a habitual strategy of co-contracting:

‘My back pain has been progressively improving since I have learnt that stiffening and tightening is not the answer to every movement. In fact, I have now found that when I relax and soften when paddling, my speed increases. As soon as I try to ‘muscle’ my way to faster performance by bracing and tightening, my speed drops!’

Training applications

There are myriad ways of training optimal dynamic control as long as you are willing to think outside the square. These strategies apply both to clients with and without back pain. A great first step is to assess your client’s breathing pattern, in low, medium and high level tasks.

Co-contractors tend to breathe shallowly in low and medium level tasks and hold their breath in higher level tasks. Begin assessing breathing with your client in a semi-supine position.

Place your hands on their rib cage and encourage them to take a deep in breath while expanding their ribs. Make sure that they are not breathing into the abdomen, as this will distend the abdominal wall, ‘blowing out’ their core.

If your client is a habitual co-contractor, it could take some time to get them to take a good, deep breath. Ask them to increase their breathing awareness during the week, focusing on taking slower, deeper breaths more of the time. A second strategy for changing the co-contraction pattern is to help your clients re-establish a brain connection with their deep stabilisers. This can only happen with an awareness of the breath, slow and controlled movements, and exercises that are very low-level. It may also involve teaching your client how to execute a voluntary pelvic floor contraction on the out-breath. This helps to ‘re-wire’ the brain connection to the deep stabilisers with the goal of this pattern becoming functional and a part of their daily movement habits. It then becomes a foundational pattern upon which medium and higher level tasks are layered.

A third strategy is to incorporate balance training (initially on stable surfaces) to encourage a softer response in medium level exercises.

When doing balance exercises, keep assessing your client’s breathing response and encourage them to stay soft throughout the static holds or range of movement balances.

And finally, we need to consider changing the words we use to encourage optimal dynamic control. ‘Brace your abdominals’ should only be a strategy for high level loads. In all cardio training, low and medium level exercises (which include bodyweight work and most exercises in yoga and Pilates classes) we should be encouraging an integrity and awareness in the core area without bracing. Using words such as ‘bring your awareness gently to your centre’ or ‘focus on maintaining soft, deep breaths throughout the range of motion’ will help our clients find a softer, more fluid way of moving that will most definitely enhance their movement performance and help prevent injury – surely a goal that’s critical for all good training sessions and great movement for life! 





 

Lisa Champion, MSc
Lisa is an exercise therapist who specialises in helping clients maximise their movement potential and minimise their risk through innovative training. Along with Anna-Louise Bouvier, she is the co-creator of the PERFECT PRACTICE (TM) training system.


NETWORK MAGAZINE • SPRING 2008 • PP52-54