Calling all movement experts!!!.…….have you read this treasure trove of an issue? JOSPT Special Issue- June, 2019

JOSPT Special Issue

June, 2019

If you are interested in Lumbopelvic Motor Control it’s a great resource that synthesizes past literature, reflects on where we have been, and where we might look to the future. This issue presents several clinical commentaries. I have chosen one of interest and the following blog references key points and provides reflections on my own practice.

Motor Control Changes in Low Back Pain: Divergence in Presentations and Mechanisms

JH Van Dieen, PhD, NP Reeves, PhD, G Kawchuk, PhD, LR Van Dillen, PT, PhD, PW Hodges PT, PhD, DSc MedDr, BPhty (Hons). JOSPT. 2019;(49)6:370-379.

I think most of us can agree, from our understanding of the theory and literature on motor control (Propositional Knowledge), from our clinical experience (Experiential Knowledge), and from our own personal experiences (Personal Knowledge)^1,2, that individuals with low back pain (LBP) move differently than those without LBP. These 3 types of knowledge, described by Higgs and Titchen, guide our clinical decision making and shape our clinical pattern development. The interesting point of this current article and one that has not been so explicit in my own mind, is that it brings to light that we don’t really understand the why behind these changes in motor control in patients with LBP……..yet!

The neuromuscular system has a variety of strategies to carry out particular tasks, and having options is thought to keep our system balanced and healthy. Yet, this variability may also be one reason why there are so many different presentations of impairments related to LBP, thus making it difficult to match the correct intervention. Which brings us to the need we have as a profession to be able to categorize patients with LBP.

The identification of subcategories of LBP is how we organize and make sense of varying presentations in order to provide the most relevant intervention. I have better outcomes when I utilize categorization systems, such as the Movement System Impairment Model, Mechanical Diagnosis and Therapy (McKenzie), Motor Control Training, the Integrated Systems Model (Diane Lee and the concept of regional interdependence)³, and Janda’s Upper and Lower Crossed, and Layered Syndromes^4,5.

In this clinical commentary by Dieen et al., the authors present an interesting new thought in this arena, one that may provide an overarching perspective on motor control changes in the presentation of LBP, though there is much work to be done to develop and validate this concept. This concept describes two possible phenotypes, either a Tight Control System or a Loose Control System. More on this later, let’s take a brief look at the evidence that is currently out there.

When considering motor control of the trunk in individuals with and without LBP, two areas have been commonly studied; trunk muscle activation patterns and trunk movements.

Changes in trunk muscle activation and muscle morphology have been observed in patients with LBP compared to those without LBP. Muscle activity has been shown to increase, decrease, demonstrate no change, activate early, and/or activate late. I think you will see some familiar patterns presented here.

Muscle	Motor control changes with LBP
Lumbar extensors  -	↑ or ↓ or no change
Transverse abdominis (TrA) and lumbar multifidus (LM) -	late activation
Abdominal muscles -	no change and early activation of oblique muscles
Muscle activity -	delayed onset or delayed offset with different intensities of recruitment
Multifidus -	muscle fiber changes Type I to Type II, muscle atrophy, fatty infiltration *indirectly changing lumbopelvic motor control

Dieen et al., offer possible reasons for the variability found in the literature and include the following: variable strategies to accomplish tasks, differing environments in which tasks are performed, the type of muscles recruited, as well as methodological differences such as how data were collected through intramuscular or surface electromyography (EMG).

The literature surrounding alignment, posture, and trunk movement presents differences in patients with LBP compared to those without LBP. Do you recognize these findings?

Changes in alignment, posture, or movement with LBP
↑ lumbar flexion	↑ postural sway, with or without balance impairments
↑posterior pelvic tilt	Slower trunk movements with dynamic tasks
↑ lumbar extension	↓ or ↑ variability of trunk movements with bending and/or gait
↑ flattening of lumbar spine	↑ coupling of pelvis/thorax with gait
No changes in alignment	↓ precision of control of trunk posture, movement, and force production

Like muscle activation patterns, changes in trunk alignment, posture and movement are different in individuals with LBP compared to those without LBP and studies also demonstrate inconsistent findings. Another issue to consider when facing the inconsistency between study results is whether motor control variability is due to intraindividual responses (within one individual) and/or interindividual responses (between individuals), thus adding another layer of complexity when analyzing study outcomes. In addition, differences in study methodology may limit study comparisons and small sample sizes may affect the validity of study outcomes.

In summary, Dieen et al. state changes in motor control are evident with LBP, are not consistent, are not seen in all patients, and in the end such changes may not be explained by a single factor. As a means to help sort out some of these different responses, the authors highlight two concepts that have been previously considered; identify the underlying mechanism for motor control changes (for example is it a strategy in response to pain/injury or a consequence of pain/injury) and identify the particular mechanical consequences of such changes.

The inconsistencies and multi-factorial nature of the findings in the literature can be confusing and potentially overwhelming. In addition to summarizing existing rationale to help explain the differing results in motor control changes seen in patients with LBP, Dieen et al. present a new concept described as “tight control and loose control phenotypes” that may help to explain the diverging responses in the literature. These phenotypes are presented on a continuum, and could explain the two ends of the spectrum as well as the middle ground where little or no changes in motor control are seen (see diagram below).

Let’s take a closer look at the two proposed phenotypes.  Both may have purposeful short-term effects, but may also have more detrimental effects in the long run.

The Tight Control Phenotype

In this scenario, muscle activation increases resulting in trunk stiffening, decreased trunk movement, increased control, and less variability of movement (or need for finely tuned anticipatory trunk reactions). This could present as a slight change in local muscle activation, to co-contraction of multiple muscles, or to a complete avoidance of a particular task. In the short term, this may “protect” the system but over the long run this may lead to increased spinal loading and less options for movement. In essence, these individuals avoid excessive movements.

The Loose Control Phenotype

In this scenario, muscle activation decreases resulting in reduced tissue loading from the larger muscles that may exert compressive forces on the spine, less control of trunk posture and movement with potentially larger variations in movement. This reduced control of the spine at both mid and end ranges, creates the potential for increased tissue strains and pain. In essence, these individuals avoid excessive muscle forces.

……..so, both scenarios can lead to abnormal tissue loading around the spine but due to different mechanisms, thus it makes sense that intervention approaches would need to be different to address the system impairments at hand.

Also, consider that these phenotypes could be present in a system at the same time, so a mixture of approaches may be needed.

Considerations for intervention approaches

We could start by asking if a tight or loose control phenotype is at play and is it in the early stages after an injury or in the later stages with more potential for negative impacts on the system?

Tight control phenotype

If your patient/client is avoiding movement, moving en bloc, or has a stiff quality to their movements consider a tight control system. Goals may be to reduce excitability and co-contraction, or “dial down overactive muscles”:

·      Utilize Janda’s theory of tonic muscles⁴ (phylogenetically older muscles⁸) to identify possible effects of a tight control phenotype

·      Assess and retrain breathing patterns

·      Post-isometric relaxation⁴ to overactive muscles

·      Facilitate the antagonists of the overactive muscles

·      Unloading techniques for the spine:

o   PT places hands on lateral sides of rib cage and lifts upward to unload the lumbar spine (in patients with a “compressed lumbar spine” this can relieve symptoms)

o   Supine with pillow under knees or hooklying

o   Quadruped⁷

o   Modified quadruped⁷ – standing and leaning on table with weight bearing through forearms

o   Lumbar self-traction in sitting (hands on arm rests and straighten elbows allowing trunk to hang with gravity)

·      Increase movement gradually, in non-threatening ways

·      Encourage variability of movement and movement in multiple planes

·      Graded exposure to avoided activities

Loose control phenotype

If your patient/client demonstrates excessive movements or aberrant movement patterns such as excessive lumbo-pelvic rotation, hinging or shearing at a specific segment consider a loose control system. Goals may be to increase excitability, or “facilitate underactive muscles”:

·      Utilize Janda’s theory of phasic muscles⁴ (phylogenetically younger muscles⁸) to identify possible effects of a loose control phenotype

·      Identify and retrain aberrant movement patterns

·      Identify the weak link in the chain and retrain that muscle or group of muscles

·      Facilitate inhibited or weak muscles in the chain⁴

·      Post-isometric relaxation to the antagonist of the inhibited or weak muscle(s)

Therefore, intervention approaches may be completely opposite depending on the phenotype that is presented or dominant.

As participants in the Movement Links Seminars and certification courses, physiotherapists have experience in looking for these divergent patterns. Through a structured exam, we look to identify aberrant movement patterns, muscle imbalances (muscles that need inhibition and muscles that need facilitation), the cause(s) as well as the source of symptoms, and develop an understanding of the relationship between impairments that are key to understanding the patient’s movement dysfunction. The end result of such a specific exam is to be able to identify specific movement impairments and their contributing factors and then provide specific interventions.

Dieen et al. state that the concept of these two phenotypes need further development and validation before they can be translated into guidelines. This development process needs to include validation of assessments related to these two phenotypes that can identify specific patterns to be treated, provide targeted intervention approaches, with the goal of improved outcomes. As such, it could be an interesting time for clinicians to write case reports utilizing tight and loose control concepts, possibly offering some support for or insight into directions for future research studies encompassing these two phenotypes.

All of you awesome clinicians out there, this is where you shine – grab a resource for writing case reports and give it a shot!

Tracey Wagner is an Assistant Professor at Samuel Merritt University teaching musculoskeletal courses and is working on developing a part-time clinical practice and her line of scholarship in the area of movement science. She is a DNS Certified Practitioner, as well as a Movement Links Certified Clinician and Instructor. She moved to the beautiful Bay Area after a 17-year career working for Kaiser Permanente Woodland Hills, serving there as a clinical specialist, mentor, and educator.   Tracey has been published in the Journal of Orthopaedic and Sports Physical Therapy (JOSPT) for a case report on muscle imbalances of a professional triathlete and received the California Physical Therapy Association’s 2010 Clinician Research Publication Award.

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References

1. Higgs J, Titchen A. Propositional, professional and personal knowledge in clinical reasoning. In: Higgs J, Jones M: Clinical reasoning in the health professions. Oxford: Butterworth-Heinemann; 1995.
2. Higgs J, Titchen A, Neville V.  Professional practice and knowledge. In: Higgs J, Titchen A, eds. Practice Knowledge & Expertise in the Health Professions. Oxford: Butterworth Heinemann; 2001:3-9.
3. Hides, JA, Donelson R, Lee D, Prather H, Sahrmann SA, Hodges PW. Convergence and Divergence of Exercise-Based Approaches That Incorporate Motor Control for the Management of Low Back Pain. J Orthop Sports Phys Ther. 2019;49(6):437-452.
4.  Page, P, Frank, C, Lardner R. Assessment and Treatment of Muscle Imbalance The Janda Approach. Human Kinetics 2010.
5. Morris CE, Greenman PE, Bullock MI, Basmajian JV, Kobesova A. Vladimir Janda, MD, DSc: tribute to a master of rehabilitation. Spine. 2006;31(9):1060-1064.
6. JH Van Dieen, PhD, NP Reeves, PhD, G Kawchuk, PhD, LR Van Dillen, PT, PhD, PW Hodges PT, PhD, DSc MedDr, BPhty (Hons). Motor Control Changes in Low Back Pain: Divergence in Presentations and Mechanisms. JOSPT. 2019;(49)6:370-379.
7. Sahrmann SA. Diagnosis and Treatment of Movement Impairment Syndromes. St. Louis MO: Mosby Inc. 2002.
8. Kolar P et al. Clinical Rehabilitation. 1^st ed. Prague, Czech Republic: Alena Kobesova, Rehabilitation Prague School;2013.