PT on the Net Research

Posture and Body Balance

Balance is a critical component to existence on this planet for all life. Our brain chemistry, muscles, joint alignment, hormones, emotions, physical body and spirit all require a certain balance for optimum function. Unfortunately, as we boldly enter the new millennium, balance in these areas eludes many of us. Therefore, rather than charging upright into the next thousand years efficiently fighting gravity, many are losing this all-important fight with serious repercussions to the body, mind and soul.

Consider this statement by Basmajian: "The importance of good posture to the body as a whole is summed up well by saying, 'Maximal health and good posture are reciprocally related - that is, one depends upon the other.'"

What is good posture? What affects it and, in turn, what does it affect? In this article, I shall look at some of the factors affecting or being affected by posture including:


Breathing is one of the most important issues to consider when looking at, or trying to correct, an individual's posture. It rates number one in the body's hierarchy; it's the top of the totem pole, as the body will sacrifice everything else including posture to maintain the airway. Air is life. It's that simple. Without it, you die. You can live without food and water for a certain period of time, but not air.

Why is breathing so important to posture? The average adult breathes around 26,000 times a day. If done correctly, each and every breath can be rejuvenating and invigorating. If done incorrectly, the rib cage becomes exactly that - a cage locking up and restricting the normal function of the respiratory system. There are two options when it comes to getting air into the lungs: nose and mouth.

Human beings come into this world as nose breathers. We are "obligate nose breathers," to be scientific, which means we do not possess the voluntary ability to breathe through our mouths. Mouth breathing is a learned response triggered by emergency stress. ~Douillard

An infant with a blocked nose fighting for nasal air begins to suffocate and cries. The crying forces air into the lungs via the mouth. Mouth breathing gets large volumes of air into the lunges quickly to deal with the emergency. Once the nose is clear, the child returns to nose breathing until the next threat to survival. From this early conditioning, the child learns under the first sign of stress to switch to the emergency pattern of mouth breathing.

Nasal anatomy reveals a make up of turbinates - or ridges - which act as turbines swirling the air into a refined stream most suitable for oxygen transfer. Turbinates, along with the septum and the pharyngeal wall, create obstructions for air passing through the nasal passageways. It is by these obstructions that particles are removed from the air; each time air hits one of these, it must change direction. And as the particles suspended in the air have more mass than the air, they can't change their direction as quickly and results in the particles striking the surface of the obstruction. This mechanism for removing particles from the air is called "turbulent precipitation," and it is tremendously efficient as almost no particles larger than four to six microns in diameter (this is smaller than the size of red blood cells) are able to enter the lungs through the nose. Air is conditioned, warmed by the extensive surfaces of the turbinates and septum, to the optimum temperature for respiration. The nasal passages' highly sophisticated design is ideal for respiration. The nasal passage is lined with mucus producing membranes. Mucus produced from the membranes ward off infection and keeps the passageway moist. The mucus membrane and small hairs work together to clean, filter and prepare the air for maximum oxygenation to take place.

Mouth breathing bypasses all these wonderful filters and allows unfiltered, cold, dry air to enter the lungs. This is not the ideal way air is intended to enter the body; therefore, it is reserved for "emergency" situations only. Mouth breathing irritates the throat, drying out the mucus membranes and increasing the risk of infection.

Nasal respiration using the diaphragm - or diaphragmatic breathing - is the most efficient means of respiration. Respiration is the exchange of gas between the lungs and the atmosphere (external respiration) or the exchange of gas between the body's cells and the blood (internal respiration). Respiration occurs as the space in the thorax changes; with this change, the pressure gradient between the lungs and the atmosphere lowers, causing a partial vacuum. This in turn causes the lungs to expand (see Figure 1). It is these spatial changes mediated by muscle action (as the diaphragm descends, the chest expands) that allows air to flow into the lungs. A positive pressure is created as the respiratory muscles relax. The diaphragm and chest return to their original size, allowing the gas in the lungs to flow into the atmosphere.

Figure 1. Ref: 23. Sagittal section through the nose; the nasal septum has been removed, exposing the lateral wall of the nasal cavity.
Figure 2. Changes of size of the Thorax and Lungs during Breathing. Ref: 24

In its relaxed state, the diaphragm appears dome shaped as it sits on top of the contents of the abdomen. It contracts, flattening and pushing the content of the abdomen down and increasing the space in the thorax. The diaphragm is considered the primary muscle of inspiration.

Figure 3. The Diaphragm. Ref: 9

Passive and active respiration are considered to be different; during passive respiration, the descent of the diaphragm is largely responsible for inspiration and relaxation of it for expiration. Active respiration requires increased volume and frequency of air. The diaphragm cannot achieve this alone; therefore, recruitment of other muscles is necessary to help out. This help comes from the external intercostal - which aids by raising the rib cage - and the abdominal and internal intercostal muscles - which return the rib cage to it's normal position - as exhalation must equal inhalation.

The sternocleidomastoid (SCM) and other muscles of the neck contribute by pulling the clavicle and first rib upward. Normal nasal respiration supports optimal physiological function within various systems of the human body including the autonomic nervous system. In optimal passive and active inspiration, there is a large degree of horizontal displacement of the thorax.

In habitual mouth breathing, however, we find that the accessory muscles of respiration including the SCM, scalene and omohyoid musculature become hypertonic.

These muscles contribute to vertical displacement of the thorax, considered to be very ineffective for respiration.

Figure 4. SCM Figure 3. Scalenes. Ref:24

This can also lead to hyper-tonicity of the quadratus lumborum and other rib cage depressors as they try to counteract the upward displacement created by the accessory breathing musculature. Postural changes are seen with habitual mouth breathers including forward head posture, forward shoulders, depressed sternum and changes to the alignment of entire kinetic chain.

Poor posture can encourage mouth breathing. Try this simple experiment. Move your chair away from your computer and sit with good posture in your chair. Your ear, the head of the humerus and the head of the femur should all be in the same vertical plane if viewed from the side. Inhale and exhale several times through your nose. Notice the effort required to do this. Continue breathing but change to mouth breathing. You will note mouth breathing in this posture requires considerably more effort than nose breathing. Continue mouth breathing, but change your posture by slumping. Let your sternum depress and shoulders roll forward. Your breathing now will most likely be much easier than when you had good posture.

While still in this slumped posture, change to nose breathing. With this change, you will see that it takes more effort to nose breathe with poor posture. This simple experiment highlights how posture can affect breathing and vice versa. Poor posture can change respiration patterns - as with the depressed sternum - and increase rib inclination. It is difficult to get the horizontal displacement required for efficient nasal respiration. This results in one of two scenarios: a change to mouth breathing and/or over utilization of the accessory muscles of respiration (chest breathing). Both of these impact negatively on the various systems operating within the body.

Nasal respiration is seen to aid functioning of the autonomic nervous system because it fills the lower lobes of the lungs, making full use of all the lungs' capacity for oxygen exchange. It is in these lower lobes that the majority of the oxygen exchange takes place. Activation of the diaphragm is said to stimulate the parasympathetic nervous system, which calms and relaxes the mind and the body. Breathing reflects every emotional or physical effort and disturbance. It is also sensitive to the vegetative processes. Disturbances of the thyroid gland, for example, cause a special kind of breathing, which serves to diagnose this disease. A look throughout history reveals many systems and rules designed to induce a calming effect by improved breathing. As breathing can be altered by changes of position, emotional state, activity level, disease and even tight garments, numerous varieties of breathing patterns have arisen. Duchenne remarked that normal breathing patterns of mid 19th century women were "of costosuperior type" because of compression from corsets on the lower part of the chest.

In looking at the human skeleton, it is constructed so that it is almost impossible to organize breathing properly without also satisfactorily placing the skeleton with respect to gravity. Reorganizing breathing alone succeeds only to the degree that we succeed indirectly in improving the organization of the skeletal muscles for better standing and movement. A balanced musculature is the most efficient in terms of energy expenditure. Teaching people to breathe diaphragmatically has helped sufferers of asthma, allergies, sinusitis and depression, and has had particular success with people suffering from anxiety and various panic disorders.

In stark contrast, the fight or flight sympathetic nervous system survival response seen with mouth breathing changes the normal chemical and hormonal balance within the body, affecting many functions. The shunting of air directly into lungs straight from the mouth appears to trigger a survival response. Researchers have suggested that chronic mouth and chest breathing can actually stimulate a sustained fight or flight form of arousal, common in states of anxiety and fear. Mouth breathers often have poor digestion, as changes in body function seen with the fight or flight response negatively affect digestion. In a full blown sympathetic response, all resources are mobilized: heart rate and blood pressure increases, blood flow to skeletal muscles, heart and brain increase; the liver releases glucose; and the pupils dilate. Simultaneously, activity of the gastrointestinal tract and blood flow to the skin is decreased by inhibitory effects (see Table 1 below).

Table 1. Ref: 23

The sympathetic and parasympathetic systems are constantly active; the basal rate of activity is referred to as "sympathetic or parasympathetic tone." Tone allows a single nervous system to increase or decrease activity of a stimulated organ. Sympathetic tone keeps almost all the blood vessels in the body constricted to approximately half their maximum diameter. By increasing the degree of sympathetic stimulation, the blood vessels can constrict even further. However, by inhibiting the normal tone, the vessels will dilate. If it were not for sympathetic tone, the sympathetic system could only cause vasoconstriction. There is an ongoing delicate interplay between these two systems which, when not in balance, can have significant influence on many systems throughout the body.

Mouth breathers often present with a tongue thrust swallow from incorrect tongue position, resulting from mouth breathing and poor posture. During developmental years, this tongue thrust is seen to alter normal occlusion, resulting in various type of malocclusion. Mouth breathers often have increased vertical dimensions in the face and jaw. This is characterized by the bottom third of the face being longer than the other two thirds. These developmental changes will not only impact dental occlusion but also the position of the temporomandibular joint (TMJ) and the disk.

With the forward head postures of mouth breathers, mandible retraction is often seen. As the mandible retracts, the disk moves anterior with inflammation of the synovial tissue and decreased joint lubrication, increasing the potential for damage to the disk. It is believed that disk regeneration is possible when occlusions are corrected and the TMJ's physiologic relationships have been restored. This is interesting for people seeking dental solution for TMJ disorder as they may also benefit from posture corrections, highlighting the usefulness of a multi-disciplinary approach to treatment.

Malocclusion may also affect digestion. As with the non physiological positions seen with malocclusion, efficient mastication may be difficult. With mouth breathing, digestive juices may also be reduced by the continual flow of cold dry air through the mouth, further affecting digestion.

Being primal beings, the survival response has its roots in keeping us alive by either fighting for our lives against an attacker or running from them. The body's priority isn't on digestion when fighting an angry caveman who wants your food, mate, shelter or all three.

At this point, it should be noted that a common exercise technique is currently being misused within the fitness industry, resulting in altered respiration. Instructors in aerobic classes, Tae-Bo and everything else in between are getting the participants to draw the belly in toward the spine as hard as possible and keep the belly drawn in continuously for extended periods of time. While this is an important exercise technique to activate the deep abdominal wall and thoracolumbar fascia mechanism (key components of stabilization of the entire kinetic chain), activation needs to be graduated and relevant to the level of effort required by the musculoskeletal system, taking into account exercise intensity and duration. Strong activation held continuously inhibits diaphragmatic breathing, leading to many of the negative changes discussed above.

For this technique to be fully effective in weight training (i.e., heavy squatting, deadlifting, overhead pressing etc.), deep abdominal wall activation should be preceded by a diaphragmatic breath to charge the thoracic cavity. The diaphragm can contribute to spinal control by assisting with pressurization and control of displacement of the abdominal contents, allowing the transverse abdominis to increase tension in the thoracolumbar fascia or to generate intra-abdominal pressure. This is difficult to do if you don't breathe using the diaphragm.


Eyesight can be an important factor when assessing an individual's posture. Poor eyesight can negatively affect posture; therefore, it should not be overlooked as part of the overall etiology of clients presenting with poor posture and or craniofacial pain. With the seated workplace being so prominent in the world today, posture is extremely important to assess, correct and monitor with clients functioning in this environment. Clients finding they need to sit very close to the computer screen or reading material could be suspected of myopia which, if left untreated, will encourage postural degeneration. If there is a chronic tendency toward forward head carriage, there may be problems with their focal vision; poor eyesight can be a cause of forward head posture.

Muscles affecting the eye and eyebrow pain (Ref: 13):

Changes in cervical and thoracic posture can influence the circulation to the head and eyes. Guyton showed that there are sympathetic vasoconstrictor nerve fibers - in addition to the local tissue regulatory mechanism -, in muscle. Approximately eight percent of nerve fibers in the average muscle are sympathetic fibers, with the potential to reduce blood flow by up to 75 percent when maximally stimulated.

Changes in posture will affect the optic plane, which ideally is horizontal. As posture degenerates with spinal changes, the eyes must compensate to maintain vision, increasing activity of the extrinsic ocular musculature. Attempts to correct posture in individuals with poor eyesight will have limited success without also correcting the eyesight problem, so refer them to an optometrist. It is also of interest to note that Chek concluded that individuals seeking help from an ophthalmologist or optometrist may benefit greatly from posture correction.

Limbic System

The limbic or emotion system can affect posture by means of how we feel. If someone is feeling depressed or anxious, this will often be reflected in their posture. The expression of the emotions in terms of movement, posture and gestures is not a new area of study. In 1921, Darwin was one of the earlier workers in the field to consider such expressions in man and animals. Emotional stress can affect the function of the internal systems of the body. Internal reactions to external stimuli are described very well by somatic definitions of reflexes seen as an adaptive response by the nervous system. Looking at the central nervous system, we see it has both structurally and functionally two divisions:

  1. Sensory division - containing sensor nerves that control your perception of the world and yourself.
  2. Motor division - made up of motor nerves controlling movements in the world and inside the body by their attachments to the muscles of the skeleton and the smooth muscles of the viscera.

Within this feedback system, there is ongoing interplay of sensory information and motor guidance. From the brain down the spine to the tailbone, the sensory nerves emerge from the backside of the spine, with motor nerves emerging from the front.

Figure 5. The Sensory and Motor Tract in the Spinal Cord. Ref: 6

Sensory nerves feed back information to the motor nerves, which respond with movement commands along the motor nerves. As movement takes place, motor nerve's feed back new information about the position of the body or body segments. Each day, stresses and traumas with resulting specific muscular reflexes are continually influencing the sensory-motor system. Reflexes being repeatedly triggered create habitual muscular contractions. As these contractions become deeply involuntary and unconscious, eventually the sensory-motor system forgets how to move freely with good posture. This is called sensor motor amnesia (SMA).

Thomas Hanna recognized three reflexes in SMA calling them:

  1. Red Light Reflex: The body's withdrawal from danger. Withdrawal is a basic neuromuscular response to stress. Worry triggers this response; the eyes and forehead musculature contract. The neck muscles contract and the head is projected forward. This causes increased stress on the muscles surrounding the base of the neck, further increasing contraction. The shoulders are elevated, raising and protracting the scapulae. The rib cage is depressed. And as poor posture and chest breathing so often go together, breathing patterns change. As the stress continues, a habit is formed. Habituation is slow and continual adaptation, which will ingrain itself into the functional movement patterns of the central nervous system. In today's society, we are inundated by stress. Anxiety is the very currency of the industrial world.
  2. Green Light Reflex: The "Action Response." This is the opposite of the red light reflex. The red light reflex contracts the anterior musculature, curling the body forward and withdrawing it. The green light reflex contracts the posterior extensor muscles, lifting and arching the back. The green light reflex is assertive. As an adaptive response, it is action. In contrast, the red light reflex is protective and withdrawing. When either of these reflexes occurs, the body's entire musculature is affected.
  3. Trauma Reflex: A sensory motor reflex. Trauma reflex is meant to guard against pain. It can be triggered by any severe damage to the body. Reflexes are often seen in one side of the body, which causes changes to movement patterns and creates further stress within the system.

Interesting research out of Canada found that electromyogram (EMG) muscle activity increased when a person was performing challenging tasks involving fear of failure. This was found to be a general human trait; researchers also found that the tension built up in those situations did not drop when the task was complete if there was no sense of completion.

Stress from family, work, finances, pain or injuries (past or present) and many things in your clients' lives could be manifesting themselves negatively in their posture. Improving posture can also have positive effects on one's emotional state. An interesting study done in the US penal system took clinically depressed inmates and sat them in front of a mirror, getting them to sit with good posture and to smile for extended periods of time. All inmates noted an improvement in feelings of well being and reduction in depressive thoughts. When we laugh, a cascade of hormones are released, positively affecting our emotions. The mind is a very powerful tool; if used positively, it is a real asset. However, negative thoughts unchecked become a liability. Just as our daily movements are creating patterns within the nervous system, our daily thoughts also do. A wise man once said that worry is a thin stream that if left unchecked will create a deep cavern with a raging river into which all thoughts will be drained.

How you sense your world and feel yourself to be is affected just as much as how you act in the world and how well your body functions by postural changes. We need to be not only aware of how we move but of also what we think and say, for it is those thoughts that entrench themselves in the nervous system, creating mental habits and patterns.

Pain, Muscle Balance and Joint Alignment

Pain has a major influence on posture. Pain can alter muscle function, creating reflex inhibition and changing movement patterns. Pain and reflex inhibition change the sensory input to the muscles when there is damage to ligaments and capsules; it can also influence the ability of muscles to support the joint. It is argued that inhibition affects the tonic motor units in the muscle, which then becomes more phasic in nature, further compromising their supporting function. Studies reveal that lack of use of tonic fibers in the anti-gravity monoarticular muscles lose their characteristics and change to resemble phasic muscle fibers over time, which can have a profound effect on posture. We should also note that poor posture could be the source of many pain syndromes, as faulty postural relationships increase strain on supporting structure. Muscle imbalance and faulty joint alignment are common sources of pain. Pain is the ultimate motivator - the body will always move away from pain. It is these pain avoidance patterns that can continue to reinforce faulty movement within the nervous system.

Fundamental in Newtonian mechanics is that the natural state is equilibrium. (L. aequilibrae, to balance). In a state of equilibrium, the sum of forces acting on the body is balanced or equal. Newton's first law, the law of inertia, states, "Everybody persists in its state of rest of uniform motion in a straight line unless it is compelled to change that state by forces impressed on it." In simpler terms, it can be said that a force is required to start a motion, to change direction or speed of a motion and to stop a motion.

When optimum muscle balance and joint alignment exists, the force required will be considerably less than in the presence of poor posture. It can be concluded that less energy will be required for movement with good posture when compared to that of poor posture, increasing energy efficiency and performance. As muscle balance and joint alignment changes, function also changes. It is these changes in function that can cause considerable wear and tear on joints and supporting structures. A lot of musculoskeletal disorders - seen as just old age - have their roots in postural degeneration. Many elderly people shuffling along the street would greatly benefit from posture corrections.

Changes in the agonist/antagonist relationships, alter posture and vice versa. This can be habitual, from the work place (i.e., taxi drivers, computer operators etc) or with continued asymmetrical muscular overuse. This is in accordance with Davis' law that states: "If muscle ends are brought closer together, the pull of tonus is increased, which shortens the muscle (may even cause hypertrophy); and if muscle ends are separated beyond normal, tonus is lessened or lost (thus the muscle becomes "weak"). With changes in muscle tonus and joint alignment, several syndromes can develop:

Joint instability is associated with muscle imbalance. If an insecure area is under constant strain, in an effort to improve stability of the body, a build up of flesh tries to wrap or splint it. This becomes evident in Dowagers Hump.

Balance and Aesthetics

Posture has a large influence on aesthetics. As the fitness industry is still largely "aesthetically driven," it is important not to overlook the role posture plays in body appearance. In his lecture series "Scientific Core Conditioning," Paul Chek demonstrates as alignment changes in the pelvis (in particular, increases in anterior tilt), this affects the position of the abdominal viscera which, instead of sitting in the pelvic basin, spill out, applying pressure to the abdominal wall. As the abdominal wall stretches, the viscera protrude outward, creating the "pot stomach" look many women and men have.

Programs designed to improve appearance without addressing postural changes will be limited in aesthetic benefits. Poor posture muscles must work more to counteract gravity's pull, expediting fatigue. Poor posture puts more strain on ligaments and abnormal strain on bones and may eventually lead to deformities. It interferes with functions such as respiration, heart action and digestion.

Musculoskeletal conditions often have patterns of imbalance (i.e., handedness, poor posture). Imbalances also may result from occupational or recreational activities where there is persistent use of certain muscles without adequate exercise of opposing muscles. Imbalances affecting body alignment are important factors in many painful postural conditions. In conditions of poor posture, there is less efficient balance of the body over its base of support. This, in turn, affects not only static but also dynamic stability, each with their own implications for pain, dysfunction and increased risk of injury.


  1. Chek. P Private consultations and correspondence: 1997- 2000
  2. Douillard. J. Body, Mind and Sport; New York : Crown Trade Paperbacks: 1995
  3. Donnelly. J.E Living Anatomy 2 nd ed. Champaign. , IL . Human Kinetics Pub Inc. 1990
  4. Chek. P. Scientific Core Conditioning Correspondence Course: A C.H.E.K Institute Publication and Production1992, 1998.
  5. Chek. P. Scientific Back Training Correspondence Course A C.H.E.K Institute Publication and Production.1994
  6. Hanna. T. Somatics; Reawakening the Mind's Control Movement, Flexibility and Health: Reading , MA : Perseus Books. 1988
  7. Feldenkrais. M Awareness Through Movement.New York.NY. Harper & Row Publishers:1972
  8. Duchenne G.B Physiology of Motion. Philadelphia : JB Lippincott. 1949
  9. Kendall F.P, & Provance P. G Muscles Testing and Function 4 th ed. Baltimore Kendall McCreary. E Williams & Wilkins. 1993
  10. Vander. A., Sherman. J Human Physiology: the mechanisms of body function & Luciano. D. 7th ed. James .A. Smith publisher. 1998
  11. Chek.P Chiropractic Approach to Head Pain: Chapter: Posture and Craniofacial Pain: Edited by Darryl D. Curl: Williams and Wilkins Publisher.
  12. Chek. P "Lost in Space" online article Personal Training on the Net. 1999.
  13. Travell J.G. & Simmons D. G. Myofascial Pain and Dysfunction: The Trigger Point Manual. Williams and Wilkins Publisher. 1983
  14. Brooke J.D & Whiting H.T.A Human Movement- A Field of Study. Henry Kimpton Publishers. 1973
  15. Guyton A.C. Textbook of Medical Physiology, 7 th ed. Philadelphia : Saunders, 1986
  16. Lehmkuhl L.D. & Smith L.K. Brunnstrom's Clinical Kinesiology 4 th ed. F.A. Davis Company. 1983
  17. Curl D.D. Chiropractic Approach to Temporomandibular Disorders. Baltimore : Willams & Wilkins. 1990
  18. Van Der Merve Dr.I. Private conversations. Sydney . 1999-2000
  19. Rolf I. Rolfing The Intergration of Human Structures Harper and Row. 1977
  20. Appell H.J. Muscular Atrophy following immobilization: a Review. Sports Medicine 10:42-58. 1990
  21. Richardson C., Jull G. Therapeutic Exercise for Spinal Segmental
  22. Hodges P. & Hides J Stabilization in Low Back Pain: Churchill Livingstone 1999. >
  23. Basmajian. J.V. Primary Anatomy 6th Ed. Williams and Wilkins. 1970
  24. Anthony C.P., Kolthoft Textbook of Anatomy and Physiology 9 th Ed. St Loius. The CV Mosby Company. 1975
  25. Wells K.F., Luttegens K. Kinesiology Scientific Basis of Human Movement W.B Saunders Company. 1976
  26. Guyton A.C. Basic Human Physiology: Normal Function and Mechanisms of Disease; Philadelphia.P.A. W.B. Saunders Company. 1971