The Physiology of Stability / Deep System Stabilisation
Myofascial trigger points represent the most typical source of pain in disturbed motor function. When Deep System Stabilisation is impaired, movement is restricted in order to compensate lost stability by reducing mobility. Professor Karel Lewit
The deep system includes the vestibular, proprioceptive and structural components informing our experience of body awareness. It is a global system predicated on experience of movement being tuned to perception of vertical, and therefore our recruitment patterns are interdependent with how movement is organised in the field of gravity. As upright mammals, the organization of our movement ideally happens around mid-line axis of the body and the understanding of this happens primarily through our gait mechanism. Practically this means attending to the length and width of the foot, the out of phase rotation of pelvic and shoulder girdles, and the experience of the neck being free, when the head is forward and up.
The motor learning theory devised by pioneering Russian physiologist/biomechanist Nikolai Bernstein hypothesised that the body uses the momentum of the limbs to optimize the degrees of freedom in the system. Imagining an elastic spring suspension analogy where the perturbations of the mass will be dependent on the damping characteristics of the spring. The brain and nervous system anticipates loads via gain in the propriosensory system and influences muscle tone to dampen the angular velocity and hence recruitment pattern of the system. Therefore, instead of the muscles of the leg lifting the limb, the antagonistic muscles are decelerating the limb towards the end of trajectory. Moreover, by using eccentric (muscle lengthening under tension) contractions the system becomes efficient via decelerating movements through enhanced visco-elastic rebound as well as the conservation of momentum. This cycle is termed a stretch-shorten cycle and is the basis of the understanding of efficiency.
Lock-Down
The source of lock-down lies in a deficit in segmental awareness. ‘Locked’ segments originate from multiple motion segments losing their segmental differentiation and being perceived as locked together as a block or unit. Deep structures are dormant and instead their role is taken over by multisegmental muscles such as external oblique, whose role is to move or brace the trunk, not to provide segmental awareness. This ‘movement compensation’ has to be changed by becoming aware of how this is happening (bodywork) and re-educating the preferred strategy through efficient breathing, optimal length-tension relationships (muscle balance) and embodied attention.
1. Slouch posture caused by lock-down in multi-segmental muscles such as external oblique and the way this communicates with the pelvis as a strategy for stability.
2. Military posture. This is the posture people adopt out of an attempt at correctness. The problem is that the sternum goes forward and the low back hollows, this is because the front of the body lengthens, causing the distance between the occiput and sacrum to shorten. The diaphragm is no longer horizontal to the up and down of the central axis.
3. Is ideal because the vocal, thoracic and pelvic diaphragms are aligned and the body is supported through congruency of the weight-bearing surfaces at the joints.
The role of the feet
The foot has 2 important functions; weight-bearing and propulsion. These functions require a high degree of stability as the surface area of the feet is relatively small. The multiple bones and joints of the feet give it flexibility and the layers of musculature combine to create lift and balance as you stand and move.
The arches of the foot are maintained by the architecture of the shape of the bones and ligaments. In addition, muscles and tendons play an important role in supporting the arches.
The 3 points of support for the feet are the 3 places where the foot’s structure will rest on the support surface. The calcaneal tuberosity, the base of the first metatarsal (big toe base), and the base of the fifth metatarsal (little toe base). The lines connecting these points represent the arches. The 3 lines of lift through which postural support is derived;
- The medial longitudinal arch
- The lateral longitudinal arch
- The transverse arch
The foot has evolved to function on uneven surfaces and to provide support and contact in different contexts. When the foot is no longer being challenged in its function, or forced to perform highly specialised tasks without reinforcing its stabilizing role, the deeper muscles that support the arches become weak or hypertonic depending on the individual context. When support is being provided primarily by the superficial, noncontractile plantar fascia, you are at high risk of plantar fasciitis and heel spurs.
Optimal full squat capability can be an interesting measure in relation to tightness and compensation. Gripping with the toes in standing is a sign that intrinsic stability is compromised.
The role of the pelvis, deep hips and pelvic floor
My clinical and lived experience has proved the difficulty of knowing ones hips, by being able to feel them. The base of the pelvis, the sit-bones and pelvic floor is truly the base of the spine as it is all one horizontal level. The pelvic basin receives the weight of the upper body and passes this weight onto the limbs via the femurs. Conversely it absorbs forces from ground reactions in moving.
If we drew a line from the tip of the coccyxs posteriorly and the pubic symphysis anteriorly, this line would be horizontal to up in ideal alignment. The strategy for checking in with bilateral standing is;
- the feet are directly under the hips with no turn out of the toes in relation to the heel
- ensuring that the symphysis is facing the horizon
- that the front ribs travel energetically down on an out-breath to verticalise the rib-cage
- to maintain the expiratory position of the ribs during inhalation
- a gentle outward rotation of the femur bones at the level of the obturators is present to bring awareness to the hips
- from a spinal perspective we lengthen from occiput to sacrum, while sending sacrum to heels, without any intention to recruit multi-segmental muscles
- in breathing, the pelvic diaphragm yields to the downward travel of the thoracic diaphragm and that the alignment of the vocal, thoracic and pelvic diaphragms maintain a horizontal orientation and are a mirror to each other in alignment.
- The neck is free of tension and the intention with head balance is forward (beginning of a nod) and up.
Obturator Internus
This muscle laterally rotates the thigh and helps to stabilise the hip joint because of its broad origin, the gemellus reinforce the action of the obturator internus.
Obturator Externus
Ideal lateral rotator of the thigh.
If we look at the hip from the side, we can see that obturator internus and gemelli run from the greater trochanter in a postero-inferior direction, while obturator externus runs anteroinferiorly. Therefore their combined action can be viewed as follows:
If the pelvis is fixed, they will pull the femur down relative to the pelvis.
If the femur is fixed they will lift the pelvis relative to the femur.
Either way they tend to ‘gap’ the hip joint. From a ‘deep system’ perspective these muscles act as sensors, proprioceptive tuners, and springs of the hip.
The role of the diaphragm
Breathing involves the passage of air into and out of the lungs, this action involves movement in 2 cavities. These cavities share certain features and have important distinctions as well. They both contain vital organs; the thoracic cavity contains the heart and lungs, and the abdominal area contains stomach, liver, gall bladder, spleen, pancreas, small and large intestines, kidneys, bladder and reproductive organs. Both share the structure of the diaphragm, it forms the roof of the abdominal cavity and the floor of the thoracic cavity. Both cavities can change shape and it is this movement which is most essential in breathing.
The abdominal cavity changes shape like a liquid ball, when it is pressed upon by the downward movement of the diaphragm, the contents below will ideally widen evenly, if the diaphragm is horizontal in its orientation. This is dependent upon postural awareness which is related to perception of gravitational vertical. Importantly the abdominal cavity changes shape but not volume (within a breathing context).
The thoracic cavity changes shape and volume, its behaviour is like a flexible gas-filled container. This is because the lungs expand and compress in concert with the action of the diaphragm and the change in volume and pressure.
Volume and pressure are inversely related; when volume increases, pressure decreases and vice-versa. On an inhalation air flows toward areas of lower pressure, increasing the volume inside the thoracic cavity. Air travels into the body by atmospheric pressure. The force that brings air into the lungs is outside the body, the energy you expend in breathing produces a change in shape that lowers the pressure in your chest cavity and air is pushed into the body by the weight of the planets atmosphere.
During relaxed breathing, an exhalation is a passive reversal of this process. During activity when the breathing rate and demand is increased, the abdominal musculature contracts to assist in exhalation and stability. In relation to breathing measured using a capno trainer (measures expired CO2), optimal scores are achieved when the participant learns to eccentrically control the ascent of the diaphragm during exhalation.
From a mechanical perspective, the diaphragm and transverse abdominus are in an agonist/antagonist relationship. During inhalation, diaphragm increases its activity and shortens and transverse abdominus decreases its activity and lengthens. The converse pattern occurs during exhalation. When the demand for respiration is increased, abdominal muscles are phasically activated during exhalation.
The diaphragm is the principal muscle that causes 3 dimensional shape change in the thoracic and abdominal cavities in breathing. L. Kaminoff
The diaphragm divides the torso into the thoracic and abdominal cavities. It is the floor of the thoracic cavity and the roof of the abdominal cavity. It structure spans from upper most at T3/4 to its lower fibres at L3, or nipple to navel in simple terms.
The abdominal cavity changes shape like a liquid ball, such as a water filled ballon. When the diaphragm travels down and presses on the abdominal cavity, the contents are compressed and if the diaphragm is horizontally orientated, the lower ribs and abdominal cylinder will widen in its circumference, and primarily laterally.
The following 13 points summarise essential aspects of optimal respiration and the health benefits associated.
1. It is important to know the location of the diaphragm and how it works
2. The diaphragm is shaped like a dome, or a bowl turned upside down.
3. The diaphragm contracts on an in-breath and travels downwards and releases on an exhalation, returning to its dome shape.
4. When the diaphragm contracts the ribs expand laterally and widen.
5. On an in-breath the diaphragm travels down, this pulls the bottom of the lungs downward, so as to bring air into the lungs.
6. When the contraction of the diaphragm is relaxed during an out-breath, the ribs return, the diaphragm travels upwards allowing the lungs to naturally empty.
7. In this natural diaphragmatic breathing the chest and clavicles remain still while the transversus abdominus lengthens and shortens in cooperation with the travel of the diaphragm.
8. The flattening of the dome shape causes rib expansion and downward travel of the lungs, bringing air into the lungs.
9. When the contraction is released and the lungs move upward, this releases air from the lungs.
10. Proximity of the heart to the diaphragm means that when breathing is rhythmical there is a natural rhythm with the lungs called ‘respiratory sinus arrhythmia’ when breathing is regulated in this way the heart speeds up during inhalation and slows down during exhalation. This allows the heart to go through a natural resting cycle with each breath. Without this the heart misses its relaxation phase of the cycle.
11. Right vagus nerve has an important relationship to heart and diaphragm. The right vagus nerve works with the heart and lungs physiologically through the motion of the lungs. This motion interrelates with autonomic nervous system and induces relaxation response.
12. Thus coordination of breath, right vagus nerve and the heart are extremely useful for health and relaxation.
13. There is enormous value in understanding the process of breathing and attending to this as a living practice.
Optimal Breathing Rate
Optimal breathing is an easy wave pattern of 8-10 breaths per minute at rest. This means that 4-5 litres of air per minute is breathed ideally through the nose. For information on 5 day courses on Breathing Integration, please contact Mark.
The role of the balance centres, occiput, cerebellum and head balance
1.Visual System: the establishment of “visual horizontal” gets primary input from vestibular system and processes incoming visual data relative to horizontal visual cues.
2.Vestibular System: via sensory input provided by the semi-circular canals of the vestibular apparatus, provides information about the three dimensional orientation of the head in space within gravity while the otoliths register linear momentum.
3.Proprioceptive System: provides rapid, detailed information about the relative position of one body part to another. Responds to changes in length and the rate of change in length occuring in muscle spindles. In the neck postural muscles are richly endowed with proprioceptors – 200-300 spindle cells/100grams as compared to 20-30 spindle cells/100grams in a power muscle such as the biceps.
The cerebellum size and sophistication is due to our need to constantly assess our relationship between body position and gravity. The major sensory tracts which branch into the cerebellum include those from the eyes, ears, touch receptors, vestibular system, proprioceptors, and golgi tendon organs. In addition to these sensory tracts, several major motor pathways feed into and exit the cerebellum,. These links include the reticular formation, the basal ganglia, the subthalamus, the thalamus, and the motor cortex.
The cerebellum monitors and modifies signals which begin and end somewhere else. The cerebellum is the great integrator of vast amounts of information, but it is never the source of that information. It takes up one tenth of the brain by volume, but contains over half of all its neurons. Its electrical activity is 10 times as fast and one tenth the amplitude of the cerebrum, which is why it took so long for its activity to be detected by neurologists.
The cerebellum continuously monitors body position relative to gravity as reported by the vestibular system and compares this to your actual location as reported by proprioceptors. The vestibular nuclei are modulated by the cerebellum and also activate the reticular activating system which is critical to our attentional system.
FM Alexander was the movement pioneer who discovered the role of the importance of keeping ones neck free of tension and head balance. Through his life and his teaching (The Alexander Technique), he has contributed important principles for understanding the general coordination of the body.
He established empirically that in posture and movement that his neck must not be stiffened, and that the head should be forward and up. The COG (centre of gravity) of the head is slightly in front of the head-atlas joint, so the head will always drop gently into ‘neutral’ when I am not holding it somewhere else (this is the forward component of forward and up). In the coaching process, I refer to this, as the beginning of a nod. The up, is the overall lengthening of the body in the field of gravity.
Dr Frank Pierce Jones, an Alexander student showed using sophisticated photography that by measuring the area under a movement trajectory/pathway you obtain an index of the efficiency of movement from the Alexander point of view, since the area increases when the neck and back are allowed to lengthen.