Neurodynamics for Pilates Teachers

Journal of Bodywork & Movement Therapies (2012) 16, 353e358

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PREVENTION & REHABILITATION: NEURODYNAMICS IN PILATES

The sensitive nervous system Once, while observing an intra-muscular injection into the gluteal muscle area of a 35 year old woman, it was apparent that the needle had struck a cluneal nerve, a sensory nerve that supplies an area of skin of the buttock. The patient, understandably and instantly, reported a sharp pain, so the needle was removed before the drug was delivered. It was what happened next that surprised me. Within seconds of the needle going in a significant wheal had formed in the skin over the path of the nerve distal to the injury. Clearly, the nerve had reacted to the needle strike by sending an afferent signal towards the Central Nervous System informing the brain of the incident, but the nerve also reacted locally, visibly downstream of the injection site with a dramatic chemical response. The skin sensation was not lost at any time, showing the nerve was still functioning, despite the injury, and the wheal settled within hours. There was no lasting effect from the unfortunate placement of the fine needle, except, for me, the graphic reminder that a peripheral nerve is not just the conductor of electrical impulses from the brain to the tissues or from the tissues to the brain, but it is also a complex physical and physiological organ within itself. A nerve is sensitive and reactive to stimulus while still being able to perform its primary role of conduction. Neurological testing in musculoskeletal medicine has traditionally been about the conductive function of the nervous system. A neuropathy caused by the compression of a nerve creates pain and an axonal conduction block (Hall and Elvey, 2004). Petty and Moore (2001) describe the effects of a peripheral nerve compression as: a reduced sensory input, reduced motor impulses along the nerve, reflex changes, pain in the myotome (a nerve root and the muscle it supplies) or dermatome (a nerve root and the area of skin it supplies) distribution, and, autonomic disturbances such as hyperasthesia (an abnormal increase in sensitivity) or parasthesia (altered sensation such as burning, prickling, tingling, pins and needles). They describe tests for the integrity of the peripheral nerves looking at skin sensation, muscle strength and deep tendon reflexes.

These blocks to conduction e such as a nerve root compression e caused by a bulging disc or peripheral nerve entrapments are relatively rare in general clinical practice (Bogduk, 2005). What has become, possibly since the (1991) publication of David Butlers ‘Mobilisation of the nervous system’, a very large component of modern physiotherapy thought is the concept of Neurodynamics. Neural tissue is a mechanical and physiological structure that interfaces along it’s path with the rest of the body and its innervated tissues. When things go wrong neural tissue itself can be the source of pain or other symptoms with a neural character without necessarily affecting nerve conduction. This is what neurodynamics is all about. ‘Mechanosensitivity is how easily the neural tissues become electrically active (produce impulses) when mechanical force is applied to the neural tissues. The more sensitive the nerve is, the less force is needed to produce activity and the more intense is the response.’ (web source 1). Michael Shacklock, a New Zealand trained Physiotherapist working in Australia, published a paper (1995) in ‘Physiotherapy’ with the aim of stimulating thought on the integration of the mechanical and physiological aspects of peripheral nervous system. In (2005) he followed this paper up with his book ‘Clinical Neurodynamics.’ This seminal systemisation of clinical neurodynamics was very well received and earned Shacklock a Fellowship of the Australian College of Physiotherapists (FACP) through original contribution by monograph (web source 2). In its preface Shacklock reports that the earliest known description of a neurodynamic test was performed using a leg straightening maneuver in the diagnosis of low back pain in workers injured while building the Egyptian Pyramids 2800 BC. The Straight Leg Raise (SLR) e a test in which a straight leg is flexed at the hip and the stretched sciatic nerve contained within can be shown to be mechanosensitive is probably a direct descendant of that original description. Butler, writing in his book ‘The sensitive nervous system’ (2000) ascribes development of neurodynamic concepts to, amongst many others, K. Bragard in 1929 who described an ulna nerve test, James Cyriax (popularly known as the ‘The

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Neurodynamics for Pilates Teachers


354 Father of Orthopaedic Medicine’) and his work on dural pain, and Geoffrey Maitland the influential Australian manual therapist and his exploration of the slump stretch in the 1970’s. Robert Elvey described, Butler identified, in 1979, a brachial plexus tension test called the Upper Limb Neurodynamic Test (ULNT). Shacklock (2005) also credits others including, Alf Breig, whose functional neuroanatomical work described movement of the nerves and who Shacklock refers to as the founder of Adverse Neural Tension. Shacklock points also to Gregory Grieve’s (1970) paper, the first peer reviewed paper on the subject that later became known as Neurodynamics. It discussed the notion of sensitivity of neural tissues being a factor in the responses to neural tests and whether spinal mobilisation could influence these mechanisms (web source 3). Adverse Neural Tension was an early term used to describe neurodynamic concepts, but Shacklock (2005) made a definite move away from using the word ‘tension’ to explain the concept as it only describes a component part of the mechanical issues of the nervous system. Tensioning the nerve in the periphery, or more centrally, the spinal cord, may produce symptoms as the structure is tensioned longitudinally. Shacklock suggests that the corollary of such a finding might encourage a therapist ‘to (over) stretch the nervous system’ which sometimes has led therapists to significantly provoke a clients nervous system. Nerve ‘stretching’ was originally suggested in the 1880’s (Cavafy, 1881) as a treatment for ataxia. In his treatment, nerves, such as the sciatic nerve, were stretched ‘violently’ resulting in a reduction of the reported pain but also with sensory and motor paralysis (which did resolve in a ‘few days’!). One patient later died convulsing violently while being given chloroform before another similar operation on his arm. Perhaps he was not quite so keen on having his nerves stretched as the surgeon supposed? Latter day ‘nerve stretches’ (neurodynamic techniques) are significantly less aggressive but sometimes the mechanosensitivity of the neural system is so acute that an extremely graded approach is required to begin treatment on a client with these findings, hence Shacklock’s (2005) systematic approach to clinical neurodynamics. ‘Neurodynamics is here to stay,’ said Butler in (2000), ‘its concepts signify a milestone in the maturing of our,’ the physiotherapy, ‘profession, as it links movement, tissues and the entire nervous system.’

Neurodynamic overview Shacklock’s Clinical (2005) bases its conceptual model on a 3 part system. The Mechanical interface, the Neural structures and Innervated tissues. The Mechanical interface is the ‘nerve bed’ e consisting of any anatomical structure that sits next to the nervous system such as tendon, muscle, bone, intervertebral discs, ligaments, fascia, and blood vessels. Shacklock likens this to a flexible telescope that ‘contains’ the nervous system and whose movements the nervous system must follow. He describes how the nerve bed elongates, shortens, bends, twists and turns resulting in simultaneous changes in the neural structures.

W. McNeill Shacklock defines a Neural Structure as any part of the nervous system from the brain, to the distal terminations of the peripheral nerves. Shacklock describes that the neural tissues have mechanical functions and should be able to withstand tension, movement, and compression. The neural tissues have physiological functions in addition to impulse conduction e intra-neural blood flow, axonal transport, inflammation and mechanosensitivity. The innervated tissues are anything the nerves supply. Muscles are an important innervated tissue as they can become locally active when a nerve displays a mechanosensitivity. The innervated tissues also provide the means to add tension into the neural system. They are, therefore, an important access point to treating the nervous tissue. Releasing a tight muscle distally may help reduce tension throughout the entire path of a mechanosensitive nerve. Shacklock’s book differentiates between general neurodynamics and pathoneurodynamics. Linking the mechanics and physiology of the nerve is the key component of understanding neurodynamics. He describes how tissues can ‘close’ around the neural tissue as well as ‘open.’ Closing may not be pathological, in fact a certain amount of pressure, he suggests, can be helpful in normalising nutrition to the nerve, however a nerve that is already sensitised will not respond normally to an every day tension, compression or movement and this, otherwise normal activity, can become neuropathic e creating pain in the neural tissue. Dysfunctions of ‘excessive closing’ can increase mechanosensitivity, but the opposite dysfunction of ‘reduced closing’ he suggests, can also be an issue. Excessive opening around a nerve can be related to joint or motion segment hyper-mobility that can allow a greater, possibly injurious, tractioning on the nerve. A failure to open can maintain pressure on the nerve, which, in time, can increase the mechanosensitivity, this can be related to stiffness in the local musculoskeletal system. Clinical neurodynamics utilises tests, best practiced, advises Shacklock, with care not to provoke a neural response. He differentiates between the words ‘provoke’ and ‘evoke.’ Neural provocation may take time to subside but by gently evoking a neural response, a therapist can gain the information required with a low risk of creating a flare of symptoms. By using neurodynamic sequencing (being aware of what movement, in what order affects the neural structures most), low forces, feeling for protection or resistance in the tissues, using short holding times and slow speeds the tests can, performed by a skilled therapist, be low risk in clients with significant mechanosensitivity. He identifies the connective tissue of the nerves as important components, particularly the perineurium and the epineurium. The perineurium Shacklock describes as ‘the primary guardian against excessive tension e ‘the cabling’ of the nerve which demonstrates considerable longitudinal strength and elasticity.’ A nerve can withstand around 20% of stretch before failure (Sunderland, 1991). The epineurium acts as padding around the axons protecting them from some of the compressive forces acting on the nerves. See Bove on this subject (2008), published in this journal. Shacklock identifies that the padding enables nerves to distort in shape and change cross sectional area during loading which is what normally happens to the ulna nerve during flexion of the elbow.

Shacklock highlights the role of intra-neural blood flow as nervous tissue is extremely sensitive to ischaemia, which can affect conduction as well as axonal transport e the movement of chemicals within the nerve. Shacklock points out that ischaemia is also easy to create despite the blood supply being coiled along the nerve to be ready for movement of the nerve, elongation of a nerve by 5e15% is enough to block the blood flow. He quotes studies showing the median nerve at the elbow has to extend its nerve bed by 20%. This discrepancy means the nervous tissue has to have normal mechanisms in place for it to cope with these forces. The sliding of a nerve in its nerve bed during movement is one mechanism. Nerves, he points out, are very good at sliding within the nerve bed by borrowing the slack in the nerves to even out the tension. The nerves can slide in an opposite direction to the movement of the joint. They can slide longitudinally or even transversely to allow the nerve to take the shortest distance between two points. Shacklock describes ‘convergence’ which is where the nerves will slide towards areas of joint movement from both above and below the joint. A treatment technique utilises the sliding action and ‘sliders,’ Shacklock suggests, do not generate much tension or compression but concentrate on the movement of the nerve which he claims to be useful to calm some symptoms. ‘Tensioners’, on the other hand, produce both elongation and compression of the nerve, and aim to improve the visco-elastic properties and physiological function of the neural structure. Blood flow to the nerve is affected by compression, which in turn can make a nerve odeamatous by the pressure blocking the drainage of blood from the nerve, this reduces oxygenation to the nerve. Shacklock identifies that the longer the time a nerves blood flow is affected, the longer the nerve takes to recover and the greater the chance that conduction of the nerve can be affected. Swelling and inflammation can lead to scarring within the nerve. Inflammation of a nerve increases its mechanosensitivity and a nerve can become inflamed just sitting next to a disc bulge due to the chemical processes in the area. Neurogenic swelling (swelling caused by the nerves) can be created by the nerves in the innervated tissues, which in can result in a viscous cycle that affects the neural tissues still more. Assessment and treatment are advocated by Shacklock. The aim is to normalise the mechanics and physiology of an affected neural structure, to improve the environment of the nerve, removing factors impinging on the nerve tissue or improving movement control of the neuromusculoskeletal system. The treatment should extend to more than just ‘treating’ the nerves by providing a fully rounded therapy to positively affect the entire biopsychosocial factors of the client being treated.

Pilates and neurodynamics Pilates is an exercise system so it stands to reason that its effects on the musculoskeletal system aim to improve posture, muscular strength and endurance, flexibility, as well as optimising movement patterns and muscle sequencing. Bernado’s (2007) paper in this Journal

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Figure 1 A. Neurodynamic test. Straight Leg Raise (SLR) test (without therapist visible passively placing the client into this end position). This example neurodynamically sensitising a standard SLR, (consisting of passive hip flexion with knee extension) with hip medial rotation, hip adduction, ankle dorsiflexion and an inverted foot. B. Pilates Exercise. A bilateral SLR position during the early part of a classical Pilates exercise ‘short spine.’ This part of the exercise has the potential to evoke a neurodynamic response, it is performed on a reformer, with load transmitted by the leg straps via a pulley from a sprung carriage. The planter flexed feet reduces some of the potential neural loading. C. Pilates Exercise. A bilateral SLR position in a ‘point and flex’ exercise on a pilates tower with the push through bar sprung from underneath. The dorsiflexed position maximally sensitizes the neural system, especially as it is loaded by the spring.



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identifies a paucity of proof of Pilates effects in the literature. This, as my own reading has identified to me, is unlikely to be significantly different now. Current motor control literature can be applied indirectly to Pilates to give a practitioner some comfort that the system has scientific credence, and anecdotally its teachers and students report good effects. I observe that the Pilates system is all about correct movement, and, teaching that movement to its clients. Teachers use their observations of their clients,

W. McNeill demonstration of the exercises, with verbal and/or handling cueing techniques, to impart instructions to those in an individual or group class. Machines or small equipment can be used to make tasks easier, or harder. Evolved pilates technique, such as breaking complex or currently unachievable exercises down to ‘prep’ or preparatory exercises to make it easier for a client to attain the exercise, is commonplace. Pilates is sometimes about providing stability at the centre and girdles to attain flexibility of the limbs and at others it is looking for spinal mobility and

Figure 2 A. Neurodynamic test. Slump test (without therapist visible passively placing the client into this end position). A spinal slump is performed consisting of thoracic and lumbar flexion. The cervical spine is flexed, the knee extended and the ankle is dorsiflexed. Releasing the head position or dorsiflexion can alter the evocation of response. These can be subtle and can be felt anywhere between the head and feet. Interpretation of the response requires clinical reasoning skills. B. Pilates Exercise. Roll down. Sequential spinal flexion. This can place the neural system into a similar position as that of the ‘Slump test.’ Commonly taught by Pilates Teachers to include a knee bend which successfully reduces tension throughout the neural system. C. Pilates Exercise. Spine stretch. Sequential spinal flexion and return. This can place the neural system into a similar position as that of the ‘Slump test.’ Note the dorsiflexed ankle position helps reduce a tendency to externally rotate the hips near the end of the full spinal and hip flexion, but also makes this exercise more likely to mechanically sensitize the neural system. D. Pilates Exercise. Roll Over. Sequential spinal flexion starting with hip then lumbar flexion. Another ‘slump test look alike.’ The cervical spine is flexed under the load of the legs and lower trunk, though the weight is also spread across the shoulders. This can be very neurodynamically evocative, especially as the feet are dorsiflexed.

spinal sequencing. The principles of centre, concentration, breathing, precision, alignment and flow are the central tenets of the technique. The mindebody link is important in Pilates as Pilates himself said ‘The Pilates Method of Body Conditioning is gaining the mastery of your mind over the complete control over your body.’ (Pilates and Miller, 1945). So it is not just about muscles. It is not just about the mind. The obvious physical link between the two is the nervous system. The physical nature of the spinal cord and peripheral nerves traveling through the musculoskeletal system means that it is affected by the movement it has helped create. When in the past the term musculoskeletal was deemed adequate, the now increasingly more prevalent term is neuromusculoskeletal, which places a correctly equal focus on the ‘neuro-’ component of the entire system. Neurodynamic analysis can perhaps also be applied to Pilates as a further layer of understanding of the effects of Pilates on the human body. If Pilates Teachers begin to analyse the effects of the movements they give in relation to the potential effects on the neural structures the analysis may suggest a change in an exercise start position, or the order in which exercises are prescribed or the ranges they dictate. Understanding how the nervous system moves through the body and how it responds to movement in both a normal and pathological way is perhaps becoming increasingly more important for a well trained Pilates Teacher. This is because Pilates is a first line contact with the general public. Those clients who have obvious neurological problems are more likely to present to their Doctor or perhaps physical therapist, but those who do not realise they have a relatively minor neurological or neurodynamic problem might discover the problem when they attend a Pilates class which moves them into new or seldom practiced postures or ranges of movement. A Pilates Teacher should know when to keep a client and modify their exercise prescription and when to refer on. A well-informed Pilates Teacher can make better decisions. A Pilates Teacher is also an end of line contact. A client with a more severe neural problem may have been managed medically, then managed under a rehab-based therapist, and only then moved on to a Pilates Teacher for maintenance or the management of preventative exercise. The Pilates Teacher should be aware of the signs that a client is slipping back into a pathological state, and be ready to refer back along the chain. Should a Pilates Teacher be ‘treating’ their clients using neurodynamic techniques? No, the ‘treatment’ of these conditions is squarely in the realm of the appropriate therapist, but a Pilates Teacher could be aware of the similarity of some of neurodynamic technique and movements within the pilates repertoire. Awareness that exercises can look like a form of a single or bilateral SLR (Fig. 1) and elicit similar responses as the SLR neurodynamic test might evoke. Awareness that a ‘roll down’, a ‘roll over’ or ‘spine stretch’ looks a little like a slump stretch (Fig. 2). Awareness that sensitising factors in an arm opening may make this gentle exercise react like a median nerve upper limb neurodynamic test (Fig. 3). The Pilates Teacher should continue to practice teaching Pilates but be aware of the normal or pathological neurodynamics lurking beneath the surface.

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Figure 3 A. Neurodynamic test. Median Nerve Neurodynamic Test (without therapist visible passively placing the client into this end position). The sensitizing contralateral side bend of the neck moves the brain and spinal cord so that there is increased tension on the nerve trunks leaving the cervical spine to go down into the arm. The shoulder is abducted to 90 degrees and the shoulder is also externally rotated, the fingers and wrist are extended before the elbow is extended. It is normal to feel some pulling across the front of the elbow. B. Non classical Pilates Exercise. Arm opening, alternatively known as ‘open book.’ This exercise involves rotation of the thoracic spine while opening the shoulder using horizontal extension. It starts from a side lying position with the hips and knees flexed, and with the palms together. Often taught with a soft (slightly flexed) elbow and neutral wrist, this is not often a highly neurally provocative movement unless clients perform it poorly or are already showing signs of mechanosensitivity. One potential neural compression can occur because the ipsilateral neck rotation can reduce space at the intervertebral foramen and increase ‘closure’ onto a cervical nerve root, particularly in a maturing spondolytic spine.

A Pilates Teacher should also be aware of positions that sensitise a neurodynamic test such as a contralateral neck side bend, a wrist and finger extension with a straight elbow and an abducted shoulder, a loaded dorsiflexion of the ankles with the knees straight and the hips flexed. They should also be aware of the ways to quieten down potential neural provocation and safely continue to supervise the exercise of their clients. They should be aware that the evocation of some neural sensations are to be expected with some movements, in at least some of the population. They too



358 should be aware that protection mechanisms create substitution movements e shoulder elevation, neck side bend or lateral glide towards the tensioned side. That some poor postural patterning’s or muscle balances such as a short pectoralis minor with an underactive lower trapezius/serratus anterior increases the risk of compression on neural structures and that the Pilates goal of improving posture e recruiting appropriately underactive muscles, decreases this risk. It appears then that Pilates already does manage, perhaps only in an indirect way, the movement, nutrition and health of the neural structures by its focus on utilising the muscles for controlled movement. Pilates is not just dynamic, it is also clearly neurodynamic.

W. McNeill Grieve, G., 1970. Sciatica and the straight-leg raising test in manipulative treatment. Physiotherapy 56, 337e346. Hall, T.M., Elvey, R.L., 2004. Management of mechanosensitivity of the nervous system in spinal pain syndromes. In: Greives Modern Manual Therapy, third ed. Elsevier Churchill Livingstone. Pilates, J.H., Miller, W.J., 1945. Return to Life through Contrology. Republished 1998 in A Pilates’ Primer: The Millenium Edition. Presentation Dynamics. Petty, N.J., Moore, A.P., 2001. Neuromusculoskeletal Examination and Assessment. Churchill Livingston. Shacklock, M., 1995. Neurodynamics. Physiotherapy 81, 9e16. Shacklock, M., 2005. Clinical Neurodynamics. Elsevier Butterworth Heinemann. Sunderland, S., 1991. Nerve Injuries and Their Repair. A Critical Appraisal Churchill Livingstone, Edinburgh.


References Bernardo, L., 2007. The effectiveness of pilates training in healthy adults: an appraisal of the research literature. Journal of Bodywork and Movement Therapies 11 (2), 106e110. Bogduk, N., 2005. Clinical Anatomy of the Lumbar Spine and Sacrum. Elsevier. Bove, G., 2008. Epi-perinneurial anatomy, innervation, and axonal nociceptive mechanisms. Journal of Bodywork and Movement Therapies 12, 185e190. Butler, D., 1991. Mobilisation of the Nervous System. Elsevier. Butler, D., 2000. The Sensitive Nervous System. Noi Group. Cavafy, J., 1881. A case of sciatic nerve-stretching in locomotor ataxy: with remarks on the operation. The British Medical Journal Dec 17, 973e974.

Web sources

1. www.neurodynamicsolutions.com/solutions-clinical-MSF.php 2. www.neurodynamicsolutions.com/news.php#bookaward 3. www.neurodynamicsolutions.com/news.php#grievelecture

Warrick McNeill, Dip. Phyty. (NZ) MCSP, Associate Editor,* Physioworks 4 Mandeville Place, London W1U 2BG, UK *Tel.: þ44 7973 122996. E-mail address: [email protected]