Consider the analogy of human motion as similar to music made from a guitar. Music is the product, the result of the individual components of the guitar working together. A guitar must be tuned, as it is this tuning that establishes the relationships and hierarchies of musical notes available to the performer. Notes that are required for the music may not be available on a guitar that is out of tune. This puts real mechanical strain on the performer and guitar. A guitar that is out of tune will burden the performer as they search for awkward positions to find the needed note to support the performance. The guitar cannot readily adapt and will likely experience some break down over time as the same strings are played over and over again and other strings are left untouched as they cannot support the music being played. The performer will find strain and bad habits produced as the guitar is not an efficient instrument.
However tune the instrument and all notes become available and easy to locate to the trained musician. Music with higher levels of complexity are attainable with this tuned instrument. In the human body, this change is seen during interventions for increasing mobility and stability. There is the mechanical change, and there is also the critical neurological change if the new available ROM or position is to be utilized by the nervous system. As the human body has greater coordination and consolidation of basic movement patters, higher levels of complex movement are available. Change when performed within the context of the hierarchical arrangement of the movements available in the body will result in long term capacity and on-going renewal of the body as it responds to the forces by building increasing strength and capacity.
Interventions are more successful in this structure. Using the movement curriculum, an inadequate performance on a contributing body segment can be seen as a remediation opportunity. Performance has been inadequate and after an assessment of the underlying causes of the inadequacies, a re-teaching occurs, providing valuable motor learning. This is critical as it is changes in the nervous system that are being corrected as well as at the muscle and joint level. Without the context, the unsupported movement patterns that have been “learned” by the nervous system will continue to be produced with only correction of the joint.
One of the dominant notions has been that of the intervention as a tool of correction to restore function. The notion is that full function is just on the other side of the wall that is limiting the function capacity of the patient. Break through and eliminate the impairment and function will be restored.
Spontaneous return of function after the “releasing” of impairment
Vs.
Availability of body segments to support the hierarchy of critical tasks that support the COG and BOS relationship.
Here is a thought experiment to consider for the movement professional. Both of the above statements refer to increasing mobility of a segment or joint. A successful intervention will make a motion available to the brain. How is the brain to use this available motion? If the brain is seeking a functional outcome the COG BOS relationship will be dominant. As a result that motion will be employed on behalf of the COG BOS relationship.
More mobility at a joint is not always the desired result, if that new motion does not support the other component levels. An example is ankle dorsiflexion for ambulation of a patient with neurologic weakness. Dorsiflexion is part of the critical task of the tibial anterior translation during the loading response into stance phase. In the well organized extremity, adequate dorsiflexion promotes the translation which is controlled via quadriceps and gluteal control of the lower extremity. In the case of a weakened lower extremity, it may be the best course of action to allow the ankle mobility to become less than fully mobile, promoting improved control of the anterior tibial translation. How much is a judgement call by the rehabilitation professional as it is essential to understand the role of dorsiflexion on the foots capacity to form an adequate BOS. To release the gastroc soleus to full mobility would undermine the function. Seen within the context of the functional result desired and the critical tasks that support the COG BOS relationship, the clinician is better positioned to intervene on behalf of improved function.
To make an intervention from a place of clarity of cause and effect and a clear observation without the assumptions of what should occur is a firm footing for producing the change effort desired by the patient.