Diane Lee and Mark Jones

Would you please explain the key features you assess during your analysis of standing posture and how you determine whether asymmetries identified are relevant or not to that patient’s presentation?

This is a great question and highly appropriate since many clinicians get ‘bogged down’ with findings that at the end of the examination have no clinical relevance. Meanwhile, they are overwhelmed by information and what it all means.

Standing is the starting point for many functional tasks including:

1. Standing for prolonged periods of time
2. Sitting
3. Squatting
4. Lifting
5. Running
6. Climbing stairs
7. Reaching overhead

A quick screen of standing posture allows the clinician to interpret what happens during movement more accurately. Very few of us stand perfectly aligned and asymmetries in multiple regions of the body are common. So, when are they relevant to the clinical picture? In short, they are relevant when the individual is held in the asymmetric position and is unable to move, or control, the asymmetric region when they need to do so. For example, in standing it is common to find the pelvis rotated in one direction in the transverse plane and the thorax rotated in the opposite direction. For a squat task, both of these transverse plane rotations should unwind and the pelvis and thorax should align symmetrically. Loads are increased through the lumbar spine if the thorax and pelvis remain rotated in opposite directions during the squat (Al-Eisa et al 2006).

A thoracic ring is defined as two adjacent thoracic vertebrae, the left and right ribs of the same number as the inferior vertebra, the sternum or manubrium to which the ribs attach and all the joints that connect these bones (Lee D 1994) (Figure 1a). Each thoracic ring has the potential to rotate in the same or opposite direction to the one above/below. So while a quick screen of the thorax is regional (lower, middle, upper), a more detailed segmental thoracic ring analysis considers the positional relationship between each thoracic ring and provides information as to which thoracic ring is ‘driving’ the regional rotation. Linda-Joy Lee has developed novel assessment techniques (Lee L-J 2003a, b, 2005, 2007, 2008, 2012) for analysis of both position and mobility of an entire thoracic ring. These particular tests, combined with biomechanical and arthrokinematic mobility tests (Lee D 1993, 1994, 2003), were used to understand the clinical relevance of Tara’s specific thoracic rings shifts as noted above.
A thoracic ring shift is another way of saying that the thoracic ring is positioned in rotation. The word ‘shift’ refers to the direction of translation of a thoracic ring, which is a congruent motion that occurs when the thoracic ring rotates (Lee D 1993) (Figure 1b). This translation is easy to detect when the thoracic ring position is assessed in the mid-axillary line (Lee L-J 2003a, 2005, 2008, 2012).

The clinical relevance of each asymmetry is determined by correcting the rotation/shift and assessing:

1. Whether a correction is possible or not (stiff, fibrotic or fixated joints will not allow the alignment of the thoracic or pelvic ring to correct)
2. The impact of the correction on the position/alignment of the other noted asymmetries
3. The impact of the correction on performance of the task being evaluated (standing posture, squat, arm elevation, one leg stand etc.)
4. The impact of the correction on the patient’s symptom experience (pain, tingling, burning, ability to breathe etc.)

Essentially, to understand the relationship between the thoracic rings and the pelvis, look for the ‘ring’ whereby the biggest resultant change in posture/position is created by a single or combined correction. Then determine if this correction also improves the alignment, biomechanics and/or control of other regions of the body during the task being evaluated.

In The Integrated Systems Model for Disability and Pain (Lee L-J & Lee D 2011), this is called ‘Finding the Primary Driver’. Of note, the position of the trunk (thorax and pelvis) can also be influenced by the posture/position of the lower extremity, shoulder girdle, head and neck, so the ‘driver’ may not be within the trunk!

Postural asymmetries fall under the hypothesis category of ‘Contributing Factors’. Like all health risk factors, they will not always result in symptoms or dysfunction as they represent only one factor within the biopsychosocial makeup that determines health and function. Therefore, as emphasised in this Answer, clinicians must have a clear rationale for each assessment performed, and since asymptomatic postural asymmetries are common, specific strategies for judging their likely relevance to an individual’s presentation are essential.

Please discuss how you relate your analysis of regional and segmental postural corrections to contemporary motor control theory and highlight what you attend to visually, kinaesthetically and via patient response in determining their relevance. Would you also comment on the current levels of evidence underpinning this assessment?

Multiple studies suggest that the response to back pain is individual and task specific (see review article on pain and motor control: Hodges 2011), although there are common features to most clinical presentations. Hodges (2011 p 222) notes that back pain patients present with a “redistribution of activity within and between muscles (rather than inhibition or excitation of muscles in a stereotypical manner)”. All of the multisegmental muscles of the trunk contribute to movement and control and when their activity is ‘redistributed’, they can produce specific vectors of force that contribute to thoracic ring shifts and pelvic rotations. Thus, Hodges states ‘If the goal of rehabilitation (e.g. using motor learning strategies) is to modify the adaptation (remove, modify or enhance) then this needs to be considered on an individual basis with respect to the unique solution adopted by the patient’ (Hodges 2011 p 222-223).

The clinician’s challenge is to determine which muscles are ‘actors’ (creating the primary vector of force) and which are ‘reactors’ (reacting to the primary vector). Increased muscle activation noted on palpation or during a certain posture (standing, sitting) or task (seated trunk rotation, single leg standing) does not mean that this muscle should be released or stretched. Releasing ‘reactors’ allows the primary muscle (the actor) to increase the rotation/twist (and often the symptoms). Therefore, when looking for the driver, the clinician should also pay attention to the vectors of resistance to movement encountered during specific corrections and the location, direction, length and velocity of pull of the vector upon release of the correction. This vector analysis provides further information about the underlying source of the pull (articular, myofascial, neural, visceral) (Lee D, Lee L-J 2011a).

The patient is engaged (focused attention and awareness) in this entire ‘correct and release’ process and is asked to provide feedback on their experience. Symptoms should not increase when the driver is corrected; rather, a sense of well being, or ease, in the body is desirable, as is an improvement in the ability to breathe or any lessening of intra-abdominal, intra-thoracic or intra-cranial pressure. Less effort should be required to perform the task when the driver is held in a corrected position and the alignment, biomechanics and control are facilitated.

I am unaware of any research that has considered changes in the ‘gestalt’ of the patient’s experience specifically with thoracic ring corrections, or any research that has investigated the impact of thoracic ring corrections on pelvic position, hip position, foot position etc. Currently, there are no measuring systems that are able to accurately measure segmental thoracic ring position or mobility, nor intra-pelvic mobility. These are clinical observations.

Application of research evidence to practice is challenging and requires judgment regarding the applicability of findings from the population studied to your patient and their context, and whether the intervention can be replicated in the clinic. Often insufficient information is reported on precisely what was implemented in the study, including details of treatment (e.g. positions, dosage, sequence, progression), patient-therapist therapeutic alliance (e.g. rapport, collaboration) or therapeutic education (e.g. explanations, advice, instructions) to enable clinicians to replicate the assessments and management (educatively, behaviourally and humanistically) with confidence. In the absence of empirical research evidence, as acknowledged here, existing biologically plausible theory (e.g. Hodges 2011) can be applied to clinical practice, combined with careful monitoring of individual treatment effects to guide reasoning and overall management. While monitoring of outcomes to judge overall success will include any changes in the patient’s activity (function) and participation restrictions and capabilities, monitoring (reassessment) to determine relevance of physical findings, specific treatment interventions and progression of treatment requires attention to broader and more detailed (often qualitative) variables as discussed here. These can include patient awareness and individual muscle activation patterns, and their effects on patient symptoms, thoughts, movement control, and other body sensations experienced during the functional task.

DRA assessment (manually and via ultrasound) will be less familiar to many clinicians. Please discuss this in the context of your broader motor control assessment and highlight your hypotheses regarding Tara’s findings with respect to her complaints and your management.

There is very little evidence to guide management of post-partum women with DRA (Beer et al 2009). Which patients are appropriate for conservative treatment and which ones will also require surgery? The distance between the left and right rectus abdominis (IRD) has been investigated in women through pregnancy and beyond, and it is thought that 100% of women have widening of the LA (increase in the IRD) during pregnancy (Gilleard & Brown 1996, Mota et al 2014) but that some remain abnormally widened in the post-partum period (Coldron et al 2008, Liaw et al 2011, Mota et al 2014). UI is a reliable method for evaluating the IRD (Coldron et al 2008, Mendes et al 2007, Mota et al 2012).

Many believe that the DRA should ‘close’ for restoration of optimal function of the abdominal wall (Mota et al 2012, Tupler et al 2011). While this may seem intuitive, our clinical experience with over 100 women with DRA revealed that the DRA ‘opened’ (IRD became wider) as their abdominal wall function improved. This finding led us to question the goal of restoring strategies that merely ‘close’ the DRA. This was later confirmed by our research (Lee & Hodges (submitted)) that suggested that the ability to generate tension of the LA is more important than the IRD and that training strategies that merely reduce the IRD may be sub-optimal for function.

Pascoal et al (2014 p 4) noted that in post-partum women the IRD decreased during a curl-up task and suggested that:
‘abdominal strengthening exercises contribute to the narrowing of the inter-rectus distance in postpartum women. However, research should be undertaken to evaluate which exercises are the most effective and safe for reduction of the inter-rectus distance in postpartum women.’
This suggests that exercises should be chosen that reduce the IRD, in other words, close the gap. Mota et al (2012) found that the IRD was greater during an abdominal ‘drawing-in exercise’ than in both the rest position and an ‘abdominal crunch’ in their study of post-partum women. Our results for the IRD during a curl-up task in post-partum women with DRA (Lee & Hodges (submitted)) concur with the findings of both Mota et al and Pascoal et al; however, our conclusions from the results and recommendations for treatment differ since we also considered the distortion/laxity response of the LA during two different strategies for this task.

We investigated the LA in two conditions; an automatic curl-up strategy and a strategy with a cue to pre-contract the TrA prior to the curl-up. In our healthy, nulliparous controls, the IRD remained unchanged during the curl-up task with or without pre-activation of TrA. In other words, the LA in our healthy controls did not distort; it remained tensed. In the subjects with DRA, the IRD narrowed from the rest position during an automatic curl-up strategy and widened compared to their automatic strategy when they pre-activated TrA. These findings suggest that co-activation of the abdominals will widen the IRD and is more likely to generate tension across the LA (i.e. create less distortion).

Clinically, it appears that generating tension in the LA (create less distortion) is more important than closing the IRD. Those who can achieve co-activation strategies of the abdominal wall that are synergized with appropriate activation of the diaphragm, pelvic floor muscles and back muscles are able to transfer loads with better alignment, biomechanics and control. Clinicians often note the depth of the LA during a curl-up task and question the significance of this finding. We feel that this is merely a reflection of the distortion (laxity) of the LA during this task, the greater the distortion the deeper you can push the LA into the abdomen (Lee & Hodges (submitted)).

Tara did not have a tear of her LA (contrary to her her cognitive belief). Structural integrity of the LA could be imaged throughout its entire length and there was no herniation of abdominal contents. She did have a sub-optimal motor control strategy of the abdominal muscles during the automatic curl-up task in that she had difficulty recruiting the right TrA. This asymmetric abdominal activation appeared to contribute to the distortion of the LA, resulting in insufficient tension for transferring loads. When the 8th thoracic ring shift was corrected, she was able to recruit the right TrA and co-activate it with the rest of the abdominals during the curl-up. Co-activation of all her abdominals widened the IRD resulting in less distortion of the LA.

Tara’s IRD at rest (25.5 mm) classifies her as having a DRA according to Beer et al (2009) (IRD greater than 13mm ± 7mm just above the umbilicus). The clinical and UI findings suggested her DRA was functional and not requiring surgery; findings from the next test would confirm or negate this hypothesis.

This analysis represents an example of ‘Inference to the best explanation’ (or abduction) as discussed in Chapter 1. In the absence of research validated criteria for deducing the effects of abdominal activation strategies (e.g. automatic curl-up versus curl-up with pre-activation of TrA) on the LA and controlled load transfer in women with DRA, extensive clinical experience led to the discovery of patterns in previously unlinked information (LA tension as opposed to IRD) through ‘Inference to the best explanation’. This culminated in the clinical recognition/theory that LA tension generated through abdominal wall co-activation is more important than IRD to load transfer and function. The ‘clinical evidence’ regarding load transfer and function was confirmed with research that investigated the effects of different activation strategies on the LA. While research is essential to test clinical theory, clinical practice cannot be limited to research-validated knowledge (assessment and management) because it only forms one of the three elements of evidence-informed practice, the others being clinical expertise and patient values (see Chapter 5). Critical, reflective clinical reasoning, incorporating deductive and inductive inferences on the basis of what is ‘known’, and on consideration of the ‘best explanation’ when dealing with areas that are less well understood, safeguards against errors in reasoning (see Chapter x) and enables the discovery of new knowledge. The clinical relevance and therapeutic efficacy for the individual patient, as discussed here, will always be essential to establish.

DRA assessment (manually and via ultrasound) will be less familiar to many clinicians. Please discuss this in the context of your broader motor control assessment and highlight your hypotheses regarding Tara’s findings with respect to her complaints and your management.

There is very little evidence to guide management of post-partum women with DRA (Beer et al 2009). Which patients are appropriate for conservative treatment and which ones will also require surgery? The distance between the left and right rectus abdominis (IRD) has been investigated in women through pregnancy and beyond, and it is thought that 100% of women have widening of the LA (increase in the IRD) during pregnancy (Gilleard & Brown 1996, Mota et al 2014) but that some remain abnormally widened in the post-partum period (Coldron et al 2008, Liaw et al 2011, Mota et al 2014). UI is a reliable method for evaluating the IRD (Coldron et al 2008, Mendes et al 2007, Mota et al 2012).

Many believe that the DRA should ‘close’ for restoration of optimal function of the abdominal wall (Mota et al 2012, Tupler et al 2011). While this may seem intuitive, our clinical experience with over 100 women with DRA revealed that the DRA ‘opened’ (IRD became wider) as their abdominal wall function improved. This finding led us to question the goal of restoring strategies that merely ‘close’ the DRA. This was later confirmed by our research (Lee & Hodges (submitted)) that suggested that the ability to generate tension of the LA is more important than the IRD and that training strategies that merely reduce the IRD may be sub-optimal for function.

Pascoal et al (2014 p 4) noted that in post-partum women the IRD decreased during a curl-up task and suggested that:
‘abdominal strengthening exercises contribute to the narrowing of the inter-rectus distance in postpartum women. However, research should be undertaken to evaluate which exercises are the most effective and safe for reduction of the inter-rectus distance in postpartum women.’
This suggests that exercises should be chosen that reduce the IRD, in other words, close the gap. Mota et al (2012) found that the IRD was greater during an abdominal ‘drawing-in exercise’ than in both the rest position and an ‘abdominal crunch’ in their study of post-partum women. Our results for the IRD during a curl-up task in post-partum women with DRA (Lee & Hodges (submitted)) concur with the findings of both Mota et al and Pascoal et al; however, our conclusions from the results and recommendations for treatment differ since we also considered the distortion/laxity response of the LA during two different strategies for this task.

We investigated the LA in two conditions; an automatic curl-up strategy and a strategy with a cue to pre-contract the TrA prior to the curl-up. In our healthy, nulliparous controls, the IRD remained unchanged during the curl-up task with or without pre-activation of TrA. In other words, the LA in our healthy controls did not distort; it remained tensed. In the subjects with DRA, the IRD narrowed from the rest position during an automatic curl-up strategy and widened compared to their automatic strategy when they pre-activated TrA. These findings suggest that co-activation of the abdominals will widen the IRD and is more likely to generate tension across the LA (i.e. create less distortion).

Clinically, it appears that generating tension in the LA (create less distortion) is more important than closing the IRD. Those who can achieve co-activation strategies of the abdominal wall that are synergized with appropriate activation of the diaphragm, pelvic floor muscles and back muscles are able to transfer loads with better alignment, biomechanics and control. Clinicians often note the depth of the LA during a curl-up task and question the significance of this finding. We feel that this is merely a reflection of the distortion (laxity) of the LA during this task, the greater the distortion the deeper you can push the LA into the abdomen (Lee & Hodges (submitted)).

Tara did not have a tear of her LA (contrary to her her cognitive belief). Structural integrity of the LA could be imaged throughout its entire length and there was no herniation of abdominal contents. She did have a sub-optimal motor control strategy of the abdominal muscles during the automatic curl-up task in that she had difficulty recruiting the right TrA. This asymmetric abdominal activation appeared to contribute to the distortion of the LA, resulting in insufficient tension for transferring loads. When the 8th thoracic ring shift was corrected, she was able to recruit the right TrA and co-activate it with the rest of the abdominals during the curl-up. Co-activation of all her abdominals widened the IRD resulting in less distortion of the LA.

Tara’s IRD at rest (25.5 mm) classifies her as having a DRA according to Beer et al (2009) (IRD greater than 13mm ± 7mm just above the umbilicus). The clinical and UI findings suggested her DRA was functional and not requiring surgery; findings from the next test would confirm or negate this hypothesis.

This analysis represents an example of ‘Inference to the best explanation’ (or abduction) as discussed in Chapter 1. In the absence of research validated criteria for deducing the effects of abdominal activation strategies (e.g. automatic curl-up versus curl-up with pre-activation of TrA) on the LA and controlled load transfer in women with DRA, extensive clinical experience led to the discovery of patterns in previously unlinked information (LA tension as opposed to IRD) through ‘Inference to the best explanation’. This culminated in the clinical recognition/theory that LA tension generated through abdominal wall co-activation is more important than IRD to load transfer and function. The ‘clinical evidence’ regarding load transfer and function was confirmed with research that investigated the effects of different activation strategies on the LA. While research is essential to test clinical theory, clinical practice cannot be limited to research-validated knowledge (assessment and management) because it only forms one of the three elements of evidence-informed practice, the others being clinical expertise and patient values (see Chapter 5). Critical, reflective clinical reasoning, incorporating deductive and inductive inferences on the basis of what is ‘known’, and on consideration of the ‘best explanation’ when dealing with areas that are less well understood, safeguards against errors in reasoning (see Chapter x) and enables the discovery of new knowledge. The clinical relevance and therapeutic efficacy for the individual patient, as discussed here, will always be essential to establish.