Developing a wellness protocol for your patients includes an overall tonal and postural evaluation with special attention to the sensory and mechanical input of the foot

Posture has long been viewed as the mainstay of spinal examinations. Traditionally, chiropractors have begun the evaluation process by analyzing distortions of posture affecting the entire body. Foot flare, tibial torsion, pelvic sway, vertebral rotation, and forward head carriage are only a few of the compensations that naturally occur as the body adapts to gravity. Posture is often viewed as a series of mechanical corrections along the kinetic chains. In fact, postural distortions are a complex result of both neurological and mechanical adaptations.¹

The original chiropractic writings by DD Palmer described overall health as a function of tone.² He understood that the tone of the nervous system affects the processing of information along the central nerves. “Nerves too tense or too slack,”³ were the cause of dis-ease in the individual. When this maladaptive state was allowed to settle over time, the ensuing result was dysfunction and disease.

Touchstone of Posture
Posture reflects the tone of the structural and functional states of the individual. For example, accumulated stress patterns are reflected in the overall posture. Neural stress causes muscular tension, which affects joint function and ultimately distorts posture. The chiropractic term for this endless cycle of structural/functional compensation is subluxation. Therefore, viewing the posture globally is an ideal component in the chiropractic evaluation.

Vertebral position and motion is grossly affected by the tone of the nervous system. Due to the intimate relationship of the central nerves within the spinal column, disturbances to the biomechanics of the spine will affect the neural tone. The central neuraxis is like a stringed instrument—any change in the tension along the musical string affects the clarity and the tone of the ensuing note. Similarly, if the spinal function is altered, there can be a distortion in the communication along the nerve. Persistent nerve interference affects the tone of both the neural and structural components, which can be reflected as a postural deficit.

An emerging body of knowledge confirms that posture is not simply a series of mechanical compensations.⁴ Proprioceptive and exteroceptive input is constantly being interpreted and modified by the muscles and joints of the entire body. Traditionally, the inner ear was seen as the prime contributor of neural input to the postural equation. Labyrinth systems are responsible for effecting balance control, but there are a host of other sensors that feed into the equilibrium system. Two prime contributors of sensory neural input are the feet and the eyes.

Data constantly streams in from a myriad of locations to the central postural computing center of the vestibular cores, cerebellum, and red cores. Optical righting reflexes combines with position and motion data from the proprioceptive systems. Forces are interpreted, and compensatory action is taken along the entire kinetic chains.

Best Foot Forward
Interestingly, it is the foot that will always intervene in postural disturbances. Regardless of the origin of disequilibria, the feet are always the final plugs between these cumulative imbalances and the ground. The foot can be seen as not only a mechanical system, but also as a sensor to the entire postural equation. Therefore, it is important to include foot evaluations when assessing the postural tone.

Ground reaction forces are transmitted through the foot and into the kinetic chain of the ankle, knee, hip, and pelvis. When the foot senses the ground, it initiates reflexual action and compensatory movements. Over time, changes to the position and motion of the foot will affect the proprioceptive input. This can change the entire postural perspective. When using biomechanical corrective devices, the importance of foot sensation must be included in the decision-making process.

As more importance is placed on evaluating the foot from a functional and mechanical perspective, it is necessary to determine whether it is an adaptive foot in the early stages of deformation or a causative foot. A causative foot is fixed and rigid without the ability to necessarily adapt to ground reaction forces, which causes postural defaults. Anatomically altered feet including severely arthritic joint structures and damaged ligament and fascial defects, can be causative.

The adaptive foot is the most common alteration, where a biomechanical and sensory shift occurs. The foot tries to adapt to the altered position and motion and, at the same time, causes altered function. Often, the rearfoot posture is observed as valgus or varus with alterations in the biomechanical capacities. The foot will allow ambulation and adaptation to the ground, despite the postural disequilibria.

Tonal-Postural Solutions
Orthotics are available in different corrective formats. The podiatric style of rigid support and correction is designed from the biomechanical perspective. Casting of the foot is done in nonweight-bearing and the talar neutral posture. There are obvious benefits to this style when the causative foot is recognized. A purely biomechanical correction can support the fixed and damaged foot. The true causative foot is few and far between. Most commonly, the adaptive foot can respond to an adaptive orthotic. This style is flexible with enough support in the midstance phase to allow for proprioceptive input into the reflex system. The foot is guided to change its posture, rather than fixed or forced into a theoretically ideal position.

Orthotic construction materials that absorb certain forces within the gait cycle can be incorporated. At the same time, these compressible polymers allow for sensory input from the joints and skin surfaces. Enough support can be achieved in these adaptive orthotics by strategically balancing the arches within the foot. As the chiropractic adjustment releases neural tension, use the foot sensors to provide more complete data to the changing spine and overall posture.

Aberrant input leads to inefficient output. The more stable and adaptive the mechanical and neural systems are, the more the person can accept and cope with change. A reversible, patho-physiologic state of inefficient energy expenditure is referred to as dysponesis.

Behavioral scientists recognized that this situation was measurable by using EMG studies in a variety of subjects.⁵ Simply put, if the person was in a constant state of disequilibria both physically, mentally, and emotionally, there were measurable postural distortions. These alterations in paraspinal activity showed up as asymmetric energy expenditures as viewed through the neuromuscular activity. Altered posture not only affects the mechanical outcomes, but ultimately disturbs the degree of adaptability of the individual. Constantly overused energetic systems of the body strains the overall well-being. Once the global effects of subluxation and posture are correlated, a more complete program of care can be offered and monitored.

Often, surface EMG is limited to observing paraspinal muscular changes. When a more detailed interpretation is included, this technology can be an adjunct to measuring the effects of the adjustment and other strategies, such as orthotic placement. William Austin, DC, Patrick Gentempo, DC, and I are undertaking an explorative study using sEMG and flexible orthotics to measure the dysponetic changes in adjusted and neutral patients. The goal of this sample will be exploring how different applications of tonal and postural strategies affect the well-being of the individual, and if these changes are reproducible.

A persistent accumulation of noxious stressors on the nervous system disturbs the natural equilibrium and creates a subluxation pattern. As the last interface with the ground, the foot must provide sensory and mechanical information to the central postural computer. Longstanding foot faults will alter the natural flow of this data and create compensatory reactions in the neural tone of the entire person.

Posture is not only a measurement of the balance of the spine, but also a complete window into the well-being of the individual.The application of an orthotic device can have significant benefits beyond the traditional view of supporting foot faults. Using technologies that identify and quantify subluxation patterns and linking these to chiropractic and orthotic interventions will provide the clinician with a unique protocol based on the original chiropractic principle of restoring optimal tone to individuals. CP

David S. Fletcher, DC, a Fellow of the College of Chiropractic Sport Sciences (Canada) FCCSS (C), has been in private practice for 22 years at The Fletcher Clinic, Pickering, Toronto, Canada. He is recognized internationally for blending traditional chiropractic principles with contemporary technologies and strategies. Fletcher can be reached at 905-831-9696 or via email: fletch5@rogers.com.

References
1. Radebold A, Cholewicki J, Polzhofer GK, Greene HS. Impaired postural control of the lumbar spine is associated with elayed muscle response times in patients with chronic idiopathic low back pain. Spine. 2001;26:724–30.
2. Palmer DD, Palmer BJ. The Science of Chiropractic. Davenport, Iowa: Palmer School of Chiropractic; 1906.
3. Stephenson RW. Chiropractic Textbook. Davenport, Iowa: Palmer School of Chiropractic; 1927.
4. Murphy DJ. Neurogenic Posture. American Journal of Clinical Chiropractic. 1995;5(1):16.
5. Whatmore GB, Kholi DR. Dysponesis: a neurophysiological factor in functional disorders. Behavioral Science. 1968;13:102.