A New Approach to Postural Function
Jiri Cumpelik
LEARNING OBJECTIVES
After reading this chapter, you should be able to:
Understand the innate human upright program that is stored in the central nervous system and awaits its invocation, perceive it and invoke it at any time, based on stimuli
Understand what forward movement is and how it manifests itself
Understand thoracic spine rotation and lumbar spine inclination, based on muscle chaining that arises from spontaneous forward movement
Understand and feel the difference between the direction of muscle pull either in the synergistic action against gravity – spinal decompression, or in the direction in accordance with gravity, causing spinal compression.
Understand the coordinated change of body posture, which does not occur successively one by one, but always simultaneously throughout the whole body.
Understand the correlation of breath pattern and posture
“Unless breathing is normalized no other movement pattern can be.
–DR KAREL LEWIT
Part I: Straightening Program
When observing humans from a developmental perspective, it is clear that there is a congenital spine straightening program programmed in the central nervous system (CNS). This uprighting program extends beyond the spine is responsible for controlling the development of the straightening and forward moving processes, which govern local and overall body stability throughout life. The postural program provides ideal support for movement and protects the movement system against tissue overload. It accomplishes this control through CNS processing of feedback and feedforward controls. Clinicians are often indifferent to the details that create the afferentation necessary for the system to function. Details such as sunken transverse arch or bunions incorrectly position the foot and alter the afferent signals from receptors. The altered signals change the input, impact the associative process, and ultimately create altered efferent motor output as well. Often these subtle changes in the straightening program go unnoticed until these small dysfunctions accumulate, the system sensitizes, and the pain alarm is sounded. The pain frequently arises in places that do not have direct or local connection to the primary cause. Connecting the dots between dysfunction and reported symptoms requires a deep understanding of the straightening program.
Understanding the straightening program, including vertical and forward orientation, forces us to recognize that the movement system cannot be represented solely on mechanical principles, although they must be considered. Mechanistic understanding and explanation is insufficient, as it is clear that both mind-set and intent are reflected in posture. Our emotions are expressed in needs and desires realized by our movements. Piaget used the term “ideation” for the process of connecting ideas with movement. We must appreciate in our assessments and interventions that position and movement is inseparable from thought and intent.
A simplified example of the role of intent would be cervical rotation with and without focus. When turning the neck to the right or left, end range is reached. If the person then repeats the motion but this time aiming to look, see, and focus on an object just out of view, an increased ease and range of motion is often experienced.
Balance—“Aplomb”
Although the postural and movement program is congenital, it is adapted through the course of life based on experience with changes inside and outside of our body. The subtle mechanisms of control are adapted and altered; this is the plasticity of the nervous system. These slight changes are often not detected by everyday training and result in altered muscle output and the inner idea of movement (body awareness) fading. It is said that movements you learn are never lost; the phrase commonly used is “it’s like riding a bike.” Although it’s true that we do not lose these motor output programs even if many years pass, what we do lose are the subtle mechanisms of control including sensitivity and responsivity. This is not caused by a loss of strength, as we sometimes mistakenly assume, but instead by the altering of motor control resulting from blurry, vague input to the CNS.
Balance is most perfectly handled by well-trained dancers. Simplified, all their training aims at strengthening single leg balance. In French ballet terminology, this skill is called “aplomb” and means perpendicularity, sureness, balance, posture. In practice this includes having one’s body under perfect control and using one’s limbs for “expression with ease.”
“Aplomb” is acquired and maintained in the course of studying and practicing dance. As the famous Russian dancer and teacher Agripa Vaganov says, “Aplomb, self-assurance, relies on balance and sensation, on the control of the muscle sensations in the body.” The daily ballet lesson starts “à la barre” (barre work) and only later it proceeds to “au milieu” (free exercise without barre). In holding the barre the dancer acquires the muscle strength as well as the feeling of support for balance. The CNS actually needs support and time using sensation to correct “aplomb” and “alignment.” The dancer then transfers the perception of the synergy alignment to the “free workout” without holding the barre. This is practiced almost daily throughout the course of the dancing career. No ballet artist dares to skip the barre work and proceed directly to the free workout. In classical ballet the barre work is irreplaceable. All attempts to innovate this process have failed. Similarly, in upright walking, we need to find “alignment” again and again. This requires practice, taking advantage of cortical plasticity to restore the straightening program and achieve ideal balance. For the nondancer to achieve this skill, it is recommended to use firm mat or floor and hold a firm support in order to enhance and refresh the right sensations (vertical and forward) required for balance.
Stabilization
Our muscular system uses two types of muscles for postural stabilization: the local muscles and sector muscles. Local muscles include intrinsic or single
joint muscles and are typically deeper than sector muscles. Sector muscles traverse several joints and are more superficial. In this arrangement the local muscles stabilize individual joints and the sector muscles interconnect joints into a bigger whole. This ensures local as well as overall body stability necessary for safe movement. The coordination and communication for this to occur is controlled by the congenital straightening program that must be repeatedly trained and refreshed and mindfully controlled.
joint muscles and are typically deeper than sector muscles. Sector muscles traverse several joints and are more superficial. In this arrangement the local muscles stabilize individual joints and the sector muscles interconnect joints into a bigger whole. This ensures local as well as overall body stability necessary for safe movement. The coordination and communication for this to occur is controlled by the congenital straightening program that must be repeatedly trained and refreshed and mindfully controlled.
Postural stability generated in this way is flexible and dynamic. Negative adaptation, incorrect exercise, or even the wrong idea (loss of intent) can create rigidity in this dynamic system. Dynamic (flexible) stability is based on coordination and synergistic function of the local and sector muscles. This involves perception by the local muscles, directing the broader actions by the sector muscles. Rigid stability appears when there is imbalance, often based on low-quality input. In short, poor input equals poor output. With this in mind, clinical assessment of the spine and peripheral joints requires understanding and perception of the difference between flexible and rigid stability. Dynamic stability does not occur directly by voluntary effort, such as exercising muscles or consciously contracting, but indirectly by subconsciously induced muscular synergy resulting from the afferent information guiding the motor (efferent) response. Ideal training must respect the inherent nature of the postural program.
Every movement must begin from a place of support. Biomechanics defines the support as a fixed point (joint/axis of rotation) acted upon by a lever (bone). The resulting movement is then defined as a system of levers acted upon by muscular strength and can be equated by quantifying the force exerted by the muscle. Although accurate in this explanation, the role of support is underappreciated. The support of the movement is created automatically and is done so at the mere intention to make a movement. The quality of the movement is as good as the support and not vice versa. The support for the movement is part of the innate straightening program and establishing support precedes the movement. The CNS is informed about the stability of the starting position by means of afferentation from the supporting point. Information from the base of support is essential for quality posture and movement.
Examples of this can be seen in the flat foot, bunions, or even subtly sunken transverse arch. The support points at the start of movement are altered and therefore the nervous system receives low quality or inaccurate information. The result of this is incorrect posture through poor coordination of sector muscles. Some individuals cope with this unfavorable situation well, others do not, but it will always create a compromise in human movement. Ideal posture or movement cannot be expected without active correction of the deformity in the base of support. The idea of placing a body part into “joint centration,” the ideal centered location of the joint and not changing the arches of the foot, does not inherently mean we have incorporated it into the general postural pattern. Centration of axial or proximal joints, without addressing decentration of the distal, supporting joints does not adhere to the congenital postural straightening program. It is the belief of the authors that the flat foot, with its incorrect supports misinforms the CNS and this is the reason why the hip or spine is uncentered during gait. Even increased intra-abdominal pressure or bracing does not adequately address this, as some have supposed. The position and muscle coordination of the feet reflects itself in the other body parts; this interrelation is inseparable and it is likely suppressed with changes made to the middle of the postural program.
Clinical Pearl
The normal function of the deep back muscles can be used as a mirror in order to understand the imperfections of erection in each pathological movement function. These are mainly deficiencies in spine elasticity, which in turn limit the function of key joints in the direction of external rotation. If the axial organ is removed from the postural pattern, the longitudinal axis of the body loses its elaticity, which manifests itself in the curvature of the spine in the sense of kyphosis or scoliosis.
Forward Movement
Forward movement consists of crawling, walking, running, and jumping always on two or four limbs. When analyzing these movements, we tend to observe and appreciate clearly visible, big, and quick movements of the limbs. But leg or arm swing is not what starts the movement of locomotion. When observing crawling we realize that the spine moves cranially. Even when we are upright with the spine straightened (elongated), the CNS and postural system remain the same: subtle cranial movement of the spine always precedes the beginning of each movement. At the moment of intention the spine stabilizes itself in the sagittal plane and provides corresponding posture facilitating shifting of body weight. This spinal movement is minute and consists mainly of movement of vertebrae that are determined by the intrinsic spine muscles.
This subtle, but perceptible adjustment of cranial movement (verticalization) and forward movement can be seen on the expression of the body posture in pictures of old Chinese qigong masters. Although the images are static positions, an astonishing energy of forward movement can be perceived when viewing them. Similar signs of posture dynamics can be inferred from pictures of young children. The dynamic, forward nature of such postures is clearly visible in contrast to exercisers who try to copy the forms of the qigong master or developing child. Although they have a model in front of them, they are not able to appreciate the essential subtleties of the spine and forward movement. This changes the expression of the position and leads to nonideal expression of the postural stabilization system. It is not sufficient to simply see the model of a child’s developmental positions and mimic them as exercise. It is necessary to appreciate the role of intent, to experience the feeling of subconscious perception and recognize their impact on dynamics of positional control. Without quality perception, feeling, and intention of the movement, the control of the position remains in a spinal cord level of agonist-antagonist. Only ideation modifies the antagonism into the synergy necessary for purposeful movement.
In Figure 30.1A and C we can see drawings of the positions of Chinese masters. These positions are outlined in simple lines. However, forward movement and energy can be perceived. When compared with the Figure 30.1B and D, where the exerciser is trying to imitate the positions, the effort is not accurate. Viewers will see a more posterior weight shift and static posture compared with the originals; in short, they lack the vertical and forward components of the postural program. The imitator does not have inner awareness of the position and intent, which means he is neither able to see and correctly imitate the position nor to perceive the difference.
Similar to the examples above, many developmentally inspired exercises show this same pattern. Even static versions of the baby or child display vibrancy, intent, and forward movement. Although the mimicking exercise appears static, many of these exercises can also be viewed to have a caudal rather than cranial vector to the stabilizing system. It is suggested that exercises that lack intent, forward orientation, and fail to appreciate the role of feeling the support zone often result in inexact copies that fail to respect the true postural program (Fig. 30.2A-D). The normal function of the deep back muscles (fig. 30. 2A and B) can be used as a mirror in order to understand the imperfections of erection in each pathological movement function. These are mainly deficiencies in spine elasticity, which in turn limits the function of key joints in the direction of external rotation. If the axial organ is removed from the postural pattern, the longitudinal axis of the body loses its elasticity, which manifests itself in the curvature of the spine in the sense of kyphosis or scoliosis.
Interrelated extension and rotational vertebrae movements are minute and remain unnoticed, but they nevertheless represent the beginning of uprighting and forward movement. Although this phenomenon is necessary for the analysis and assessment of moving patterns, it is hardly reflected in professional literature. Knowledge of these movements during the therapy actually tells us whether the straightening program for forward movement was or was not induced. The range of the movement between individual vertebrae and the cranial forward movement of the spine dictates the range of motion of limbs, particularly of shoulders and hips; if the spine is stiff, extremity joints are restricted.
For the postural program to function for spontaneous forward movement, the idea, goal, and/or purpose of the movement is also essential. The idea always precedes the movement impulse. Without this idea the movement remains unfocused and purposeless. Spontaneous movement corresponds to muscle sequencing based on our orientation in space through telereceptors. Visual, auditory, and olfactory perceptions help in informing the posture of the head, which has its supports in the whole body, thus these also inform body posture.
In coordinated forward movement, the limbs have supporting function, which shifts body weight toward the existing or future base of support. The shoulder and pelvis girdles, where the straightening of the trunk takes place, are essential in this process. The trunk is then carried, drawn, or bounced forward by the muscle function. The precondition of such movement is a distal direction of muscle pull toward the support point.
As established above, the distal direction of muscle pull along with elongation of the spine is based in ideation. The more urgent the desire to satisfy inner needs, the better the straightening and movement program works. Forward movement also provides contact and communication with the environment. The motivation of forward movement is inadvertently included in the realization of mental intention.
Trunk Stability—“Core” Stability, the Deep Stabilization System Bipedal posture has freed the upper limbs for manipulating and grip functions, but the motor program of the quadruped remains in the CNS. Bipedal forward movement is characterized by the standing and stepping limbs. While doing so, the
upper and lower limbs move in a crosswise pattern similar to crawling (an ipsilateral pattern, such as pivoting remains unclear). These innate patterns correspond with certain muscle sequences. As these patterns are global and interconnected, the role of the “core” and the terms “core stability” are suspect as they fail to appreciate the role of the extremities.
upper and lower limbs move in a crosswise pattern similar to crawling (an ipsilateral pattern, such as pivoting remains unclear). These innate patterns correspond with certain muscle sequences. As these patterns are global and interconnected, the role of the “core” and the terms “core stability” are suspect as they fail to appreciate the role of the extremities.
The term “core stability” is based on an assumption that the body has a sort of center, but this is only a convenient image for conversation because such a core does not really exist independent of the whole. The “core stability” idea also evokes the notion that the core and limbs function independently.
The movement of the body is three-dimensional, dynamic, and highly interrelated. Isolated approaches to the core have also mistakenly led to attempts to quantify joint stiffness that lead many to believe that a stiff spine is desirable and less vulnerable than a flexible one. This led some clinicians to believe the more we stiffen the muscles of the spine, the better. However, this concept of spine protection often does not take into account the compressive load that results from this approach, making it more vulnerable. Similarly, these thoughts contribute to the idea that the spine must be more protected than other parts of the body. Health care professionals as well as the general public are so influenced by these beliefs that they fail to recognize the importance of perception and understanding of one’s own body on the basis of introspection. Although exercises for “core stability” may create short-term success, in the long run they can harm the body.
We believe that every analysis and assessment must be based on the understanding of the global pattern for posture and forward movement. Isolated assessment such as focusing on deep spine stabilizers, including diaphragm, transverse abdominis or other abdominal muscles, or pelvic floor, represents assessment of a subsystem. The notion of the diaphragm, abdomen, and pelvic floor being the basis for spine support does not adequately reflect the relevance of the global pattern.
The concept of starting motion by first activating the deep spine stabilization system, antigravity muscles, and only then the global pattern for forward motion holds no support in neurophysiology. If man is not anchored in feet, he loses the ability to use the upper limbs correctly. The body straightens itself by means of hips and shoulders and the whole system then works as a spring: the more we compress the spring, the more force it generates creating compression of the spine (Fig. 30.3). The movement pattern is always initiated as a whole and the weight of the body is exercised as a whole as well.
The bigger the force (the spring being compressed), the bigger is the effort to generate a muscle force against this weight.
Clinical Tests
When testing spine stability and control, one must not only test biomechanics and muscle sequencing but also the strategy used by the CNS. Without the role of CNS being considered, the content validity of the test is questionable. For example, in the test of hip flexion, it is proposed that first the trunk stabilizers are automatically activated and secondarily the hip flexors are engaged. This sequence prevents decentering of the spine, pelvis, and ribcage during the hip flexion movement. With this type of assessment, the primary goal of assessment is to evaluate the load-bearing muscles. The authors propose that this method lacks content validity. In the global postural system, lifting of one leg (hip flexion) requires support in the contralateral leg and ipsilateral upper extremity. These essential aspects are missing from this example and so many core assessments.
The model of trunk stability shown in Figure 30.4 is based on the assumption that abdominal muscles,
together with the diaphragm and pelvic floor, create sufficient intra-abdominal pressure to protect the spine. This model is currently widely accepted because of its simplicity and support from many clinical studies.
together with the diaphragm and pelvic floor, create sufficient intra-abdominal pressure to protect the spine. This model is currently widely accepted because of its simplicity and support from many clinical studies.
The model described by Figure 30.4 utilizes so-called trunk stabilizers to prevent decentration. The assessment of this model requires palpation of the abdominal areas as marked by arrows and at times provide resistance to the thigh during its flexion of the hip (see Fig. 30.4B). The spine model in Figure 30.4C is explained by a chain, whose neutral links are primary and requires intra-abdominal pressure and creation of a caudal force vector. The idea of this model helps explain core stability in one manner, but fails to fully explain the global postural program.
Despite challenges to the chain model of spinal stability, the authors propose that when using this model the “loose” (decentered) spinal segment will more preferably hook up again through cranial movement (Fig 30.5A). This type of movement is not represented in example tests, or in many core assessments, but is present in the spring model displayed in Figure 30.5B. The spring model incorporates the crosswise walking pattern, forward movement, and essential role of base of support, all which are basic components of human posture and expression. These rely on the spine having a cranial, rather than caudal, vector as in the previous model. The cranial vector, forward motion, and role of the extremities must be incorporated for any model of spine stability to be complete.
The concept of stability being created by weight-bearing muscles differs from the concepts of developmental kinesiology. When lifting one lower limb, the contralateral limb and ipsilateral upper extremity have to be in a supporting phase; otherwise, the global pattern and its subordinate complex of diaphragm, abdominal muscle, and pelvic floor is not adequately tested. Without cooperation from these extremities, the hip flexion, and so many other core tests, does not fully evaluate the global pattern that is necessary for motion.
A similar misunderstanding arises in the clinical test of lumbar spine stability by means of isolated abdominal muscle activation such as “bracing” and “hollowing” (Fig. 30.6A and B). Neither of them takes into account the global patterns or the roles of intent, verticalization, and forward motion.
These methods again attempt to assess or intervene in the middle of the postural program without respecting the origin of the pattern or interrelatedness. Volitional activation of the abdominal muscles is assumed to generate pressure on the abdomen, create stiffness, and immobilize the spine as a measure of protection. However, these activities do not induce the spine straightening program; they only increase compression and stiffness of the spine, which comes at a cost to the spinal joints and limits motion about
the hip and shoulders. In contrast, models such as the spring, which respect the postural program, create muscle sequencing in a way that the spine is stabilized against gravity leading not to compression but intersegmental traction. In this ideal model, the spine is not stiffened, but enabled to elongate and rotate (even when loaded) by muscle synergy. The more the spring is compressed, the more anti-gravitationally the muscle synergy works.
the hip and shoulders. In contrast, models such as the spring, which respect the postural program, create muscle sequencing in a way that the spine is stabilized against gravity leading not to compression but intersegmental traction. In this ideal model, the spine is not stiffened, but enabled to elongate and rotate (even when loaded) by muscle synergy. The more the spring is compressed, the more anti-gravitationally the muscle synergy works.
The misapplications and misperceptions in assessment described above regretfully are seen in exercise as well. Exercise or training must respect the postural program and spring effect as well. In exercises where the totality of the postural program is not represented, we tend to see a common pattern of dysfunction. The thoracic spine is actually stiffened and locked and the backward movement of the head is limited. The cervical spine cannot unfold from T4 and is therefore overloaded in the C5 and C6 area. This aspect of low-quality training should be recognized in clinical tests. The locking of the spine as a means of protection limits autochthonal muscle function as a result of focusing on weight-bearing muscles and intra-abdominal pressure. The other body parts
that would need protection are conveniently ignored. Activation of the global postural program controls the intra-abdominal pressure reflexively, not through volitional effort. The central impacts to the core and spine are the result of straightening about the hips and shoulders resulting from support and afferent information from the limbs during stance and walking.
that would need protection are conveniently ignored. Activation of the global postural program controls the intra-abdominal pressure reflexively, not through volitional effort. The central impacts to the core and spine are the result of straightening about the hips and shoulders resulting from support and afferent information from the limbs during stance and walking.
Figure 30.7 Posturograph.
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