My last blog, Principles of Optimal Movement I, introduced the rehabilitation goal of movement optimization. This was defined and its’ importance in rehabilitation was articulated. Four principles of optimal movement were proposed:
- Fascio-Skeletal Weight-Bearing
- Minimization of Unnecessary Effort
- Appropriate Distribution of Movement
- Proportional Use of Synergists
Fascio-skeletal weight-bearing and minimization of unnecessary effort were covered previously; appropriate distribution of movement and proportional use of synergists are the topics of this blog.
The emerging rehabilitation principle of regional interdependence is defined as “seemingly unrelated impairments in remote anatomical regions of the body may contribute to and be associated with a patient’s primary report of symptoms.” (See excellent article in J. of Man. & Manip Ther. May 2013; 21(2):90-102. A regional interdependence model of musculoskeletal dysfunction: research, mechanisms, and clinical implications. Sueki D, Cleland J, Wainner S).
In other words, bodies are integrated; body parts don’t work independently or in isolation, but in relationship to one another. When relationships are sub-optimal, dysfunctional or invariant, tissue strain and breakdown occur. Limitation of movement in one region necessitates too much movement in another region; hyper-mobility stresses and joint instabilities occur. Lack of muscle contribution in one region necessitates too much effort in muscles of another region; hyper-tonicity stresses and muscular over-use syndromes result.
There are several examples of this distribution of movement principle from the spinal system. Places of common spinal hypermobilities are the lower neck and lower lumbar areas. Conversely, the thoracic spine and hips are commonly hypomobile. Cause and effect or cosmic coincidence? There are ample examples in the literature linking reduction of neck pain with thoracic manipulation or mobilization and many examples linking lack of hip movement (or muscle strength) with low back pain (email inquiries to firstname.lastname@example.org).
Lack of hip flexion leads to too much lumbar flexion. Hip extension or rotation lack leads to too much lumbar extension or rotation. Substitute thoracic for hip and cervical for lumbar and the same mechanisms apply. Observe the way babies link the intension to look with thoracic and pelvic movement; see the illustration and accompanying video. We know this, but tend to think that if we prescribe an exercise or apply a manual intervention to improve hip or thoracic mobility it will automatically result in improved cervical and lumbar health.
This is a leap of faith; just because something has the ability to move more doesn’t necessarily mean the habit-driven nervous system will utilize that movement in daily activities. Exercise needs to simultaneously train mobilization of hypomobile and stabilization of hypermobile areas while facilitating proprioceptive awareness of how/when to apply to functional context (looking, bending, lifting, swinging a golf club, etc.). This is what makes specific motor control exercise.
Other examples of this hypermobility/hypomobility pair principle are:
- Ankle dorsi-flexion vs. foot pronation when walking.
- Hip flexion vs. knee flexion on stairs.
- Hip external rotation vs. knee external rotation when cutting.
- Thoracic extension vs. gleno-humeral extension when reaching overhead.
Proportional use of synergists is closely related to the distribution of movement principle. Habitually insufficient muscle use somewhere necessitates too much effort elsewhere; muscle hyper-tonicity syndromes. Additionally, habitual overuse of one muscle creates agonist pair imbalances; reciprocal-inhibition-driven antagonist weakness. All the dominoes tumble and the whole system slides into dysfunction:
- Insufficient psoas use in sitting leads to overuse of abdominals and inhibition of back extensors.
- Habitual disuse of hip extensors in standing necessitates too much lumbar extensor use, which in turn inhibits the abdominal muscles.
- Insufficient thoracic extensor use riding a bike leads to overuse of cervical extensors.
- Under-utilization of hip extensors means lumbar extensor overuse when lifting.
We can train ourselves to recognize sub-optimal movement relationships, articulate how that movement contributes to or perpetuates musculoskeletal dysfunction, train our charges to recognize the error of their ways, and prescribe integrated corrective exercise. Embracing the role of movement teacher, we then need to decide what style of integrated movement we want to teach, Static or Dynamic (topic of next blog).