Good posture and how it can be achieved

Chapter 1 Good posture and how it can be achieved



CHAPTER CONTENTS


Introduction 1

Good erect posture 3

Postural faults 16

Useful tests 28

Tables of exercises for addressing postural faults 39


INTRODUCTION


Posture is an overall term comprising the relative disposition of all the many parts of the body, but particularly the shape and position of the spine. It cannot be considered in isolation but only in relation to the person’s prevailing situation or environment, which may be static or dynamic.


In a static posture, whilst a person may be standing, sitting or lying still, this should really be regarded as temporarily suspended movement or dynamic posture, as even with so-called static posture there is always a tendency to change.


In dynamic posture there are constant changes in the relative positions and alignment of all the body parts, particularly against the integral structures of the spine, as most occur during activities such as walking, running, dancing, manual handling, etc. In fact, dynamic posture simply describes the constantly changing relationship between all the parts of the body that occur during movement.


Good posture, whether static or dynamic, is difficult to define, but as all the musculoskeletal components of the body – and not just those of the vertebral column – contribute and maintain posture, the term good posture might best refer to one that puts the least strain on bones, joints and their supporting structures. In practice, good posture should equate with standing, sitting, lying or moving comfortably.


The anatomical basis of good posture can be defined as a state of muscular and skeletal balance that protects the supporting structures of the body against injury, the effects of ageing, etc., irrespective of the activity or effort involved. This is best seen in manual handling techniques designed to keep the combined load and body mass over the feet as the supporting base. It enables the individual to work safely and comfortably. In less strenuous activities, such as walking or dancing, good posture reflects poise and an unselfconscious grace, ease or even economy of movement.


Bad posture, in contrast, implies inefficient use or frank misuse of joints and associated muscles and ligaments, with progressive and, ultimately, irreversible injurious effects, with associated physical, and possibly painful disability.


Posture when observed in others may be felt to range between good and bad, and these deviations are difficult to identify without a prescription for ideal, erect human posture. However, it must be noted that in reality normal posture and particularly good normal posture rarely exists, and when assessing and correcting posture it is essential to consider inherent physical features such as body type and proportions, together with ligament length and joint mobility. For example, people with loose ligaments tend to stand with hyperextended knees and hips (resting on their iliofemoral ligaments) and with flexible, exaggerated curves of the spine that are much greater than those seen in people with tighter ligaments.


Posture can also reflect gender, personality, mood, age and state of health and can alter throughout the day, being related to stimulation or fatigue as individuals react with their environment.


Teaching good posture where it is lacking to a greater or lesser degree aims for an optimum relationship between all parts of the body at all times, so that the most effective musculoskeletal function prevails over the full range of an individual’s activities.


Such teaching can only be effective through an understanding of the basic mechanics of static and dynamic posture, and combinations of the two, and the contributions of anatomical position and alignment, and of musculoskeletal function to overall good posture.


At the same time, it is necessary to consider skeletal abnormalities of bones and joints, whether inherent or acquired as in ageing or degenerative conditions, and problems of inadequate or inefficient muscle function following injury or in neurological conditions, leading to weakness, shortening or imbalance, and their mechanical consequences.


Furthermore, as teachers, good posture is something we should be able to see and feel in ourselves. This enhances our understanding of the basic components of good posture whilst maintaining our own good musculoskeletal function. Not only is this essential for safe, effective teaching through example, it also promotes and assists the achievements of better posture in our trainees.


Whether promoting overall good posture or correcting existing elements of bad posture in individuals or groups, each trainee should be helped to understand their specific postural faults or habits. This knowledge, together with tools and strategies for improving posture, will ensure that each trainee is equipped to gain the long-term benefits of good versus less good posture.



HOW THE MODERN HUMAN REMAINS ERECT


As humans evolved, the erect posture was adopted through the development of the bipedal gait. The upper limbs were thereby freed, allowing the functional use of the arms and hands to develop more complex activities. Naturally, the erect stance could only be achieved at the expense of a greatly reduced area and strength of base support, with inevitably less stability when the body had lost the support of what had become the upper limbs. At the same time, therefore, the lower limbs gained strength and agility, and overall body mobility and stability were maintained and enhanced.


Gravity is constantly pulling the body as a whole towards the ground. This force is counteracted by the tone of the postural muscle group, a role that cannot be overestimated because the bones of the skeleton, especially the long limb bones, are too irregularly shaped to stand upon each other and maintain the upright position alone. However, muscles do not maintain the erect position alone and their ability to counteract gravity is under the control of the central nervous system which is implemented by information contributed by ligaments, tendons, joints and the muscles themselves, together with input from special senses, mainly visual and vestibular, which help to identify the position of the head in space. Other systems involved less directly by contributing to metabolic homeostasis include the respiratory, circulatory, excretory, digestive and endocrine systems (Thibodeau & Patton 1993).


Although the contributions that these systems make must be appreciated, they will not be considered here, as the topics for discussion in this chapter are posture, balance and the muscular activity involved in maintaining an erect posture.



Summary



Advantages of good posture



image It ensures that the progressive, but controlled, development of all the postural muscles is both promoted and maintained.

image It helps to maintain overall body fitness so that physical activity is efficient and well coordinated.

image It, therefore, also helps to protect the spine by aiding lifting and handling of loads efficiently.

image It helps to compensate for skeletal changes that occur, for instance in prolonged illness, as well as with advancing age.

image It helps to protect the back and prevent injury in pregnancy and during the postnatal period.

image Overall, it promotes a feeling of well-being, confidence and poise during sitting, standing, moving and general day-to-day activities.


Disadvantages of bad posture



image More rapid, and sometimes permanent, skeletal changes as age advances.

image Muscle imbalance and resulting injuries.

image Less efficient breathing and circulation.

image A sluggish digestive system.

image Lack of coordination and the ability to move with ease.

image An adverse effect on mood and well-being.

It is important to realize that bad posture, even when only temporary, as for instance with illness or pregnancy, etc., can lead to a long-term or even permanent loss of previously good posture with associated physical and sometimes psychological problems.



GOOD ERECT POSTURE


Good erect posture (Fig. 1.1) requires an understanding of the vertebral column’s structure and function as well as the basic principles of maintaining an upright stance. It also demands the ability to observe and assess posture so as to recognize common postural habits, faults and movement patterns.


image

Figure 1.1 Good erect posture.


Reproduced with permission from Sahrmann (2002).


These are discussed under the following headings:


image Basic principles of maintaining an upright stance:
– Spinal anatomical structures

– Body mass and centre of gravity

– Base of support

– Line of gravity

– Centre of pressure

– Balance and stability.

image Postural observational skills and assessment:
– Body types

– Assessment procedures

– Ideal alignment

– Easily recognized faulty postures

– Common faults in foot placement and leg alignment.


BASIC PRINCIPLES OF MAINTAINING AND UPRIGHT STANCE



Spinal anatomical structures


‘The back’ or ‘the spine’ comprises the vertebral column and associated ligaments and muscles, together with the intervertebral discs and the contents of the vertebral canal (Figs 1.2 & 1.3).


image

Figure 1.2 Side view of spine.


image

Figure 1.3 Back view of spine.


The intervertebral discs cushion the bony vertebrae, providing shock absorption and giving flexibility for the spine to move. The shock absorption properties of the discs are essential in protecting the spine from trauma during everyday activities and are particularly effective for walking, going up or down steps or inclines, running, etc. In addition, the health and integrity of the intervertebral discs determine to a great extent the overall function of the spine as the discs allow movement to occur between each vertebra during bending, stretching and twisting, and movements comprised of combinations of these possibilities.


In a healthy disc, the spongy, jelly-like nucleus is enclosed within a fibrous ring (annulus) that allows the disc to change shape during movement but prevents the nucleus leaking out. The ability of the nucleus to change shape during loading and unloading of the spine is demonstrated in Figures 1.4–1.6.


image

Figure 1.4 A Unloaded disc: side view of spine. B Loaded disc: side view of spine.


image

Figure 1.5 Forward bending.


Redrawn with permission from Oliver (1999).


image

Figure 1.6 Backward bending.


Redrawn with permission from Oliver (1999).


As the disc nucleus contains a great deal of water, constant pressure exerted on the discs throughout the day will adversely affect their overall size, sponginess and shock-absorbing properties. As the day progresses, water leaks from the discs causing shrinkage of the nucleus. This leads to a loss of disc height that results in less effective disc function and overall mobility and function of the spine itself. However, these changes are reversed during periods of rest, especially when recumbent in bed at night, and varying the amount of pressure exerted on the discs throughout the day can also help to maintain and improve disc health and function (Fig. 1.7).


image

Figure 1.7 How pressure on the discs is affected by different postures.


Redrawn with permission from Oliver (1999).


The intervertebral discs permit movement of the spine, and the range and types of movement are limited by the shape and structure of the different types of vertebra (compare the cervical and lumbar regions) and the strength and length of the ligaments. Movement is controlled by the muscles of the spine and trunk under the influence of motor nerve impulses from the brain.


In the normal spine, the small facet joints on the posterolateral aspects of the vertebrae fit neatly together, so that hyperextension and extreme twisting movements are limited. However, narrowing of the intervertebral space through an exaggerated lumbar lordosis or damage to the intervertebral discs places undue stress on the joints causing pain (Fig. 1.8).


image

Figure 1.8 Narrowing of disc space increases pressure on facet joints.


Redrawn with permission from Oliver (1999).



Muscles and ligaments supporting the vertebral column



Muscles


The erector spinae is a longitudinal mass of muscles ascending along the posterior aspect of the vertebral column from the sacrum to the skull (Figs 1.9 & 1.10A&B). This large and somewhat complex extensor of the spine is divided into three parallel columns termed deep, middle and superficial, each further subdivided into individually named components arranged in ascending series.


image

Figure 1.9 The deepest level of the spinal musculature demonstrates three primary patterns: spinous process to transverse process, spinous process to spinous process, and transverse process to transverse process. The more superficial muscles can be analysed as ever-longer express versions of these primary locals.


Reproduced with permission from Myers (2001).


image

Figure 1.10A


image

Figure 1.10B The erector spinae muscle showing its constituent parts.


Reproduced with permission from Palastanga et al (2006).



Deep layer – interspinales, intertransversarii, rotatores


image Interspinales: these small muscles, lying in series together with the interspinous ligaments, join adjacent spinous processes.

image Intertransversarii: these are a similar series of thin muscles that join adjacent transverse processes; they tend to be stronger in the upper part of the erector spinae.

image Rotatores: these join one transverse process to the spinous process of the vertebra above; they are confined to the thoracic spine, which is where the only true rotation of the vertebral column can occur.

These deep muscles are small and not individually strong; however, collectively, their close proximity to the vertebrae confers their important contribution to the integrity and correct function of the whole spine, possibly with respect to its more subtle postural adjustments.



Middle layer – multifidus, semispinalis, levatores costarum


image Multifidus: this has the deepest and shortest muscle fibres in this layer. Each extends from the laminae and mamillary processes of one vertebra to the spinous process of a vertebra that is positioned two or three segments above. Multifidus extends in series from the sacrum to the upper part of the neck.

image Semispinalis: the fibres of this muscle lie superficial to multifidus, and extend over three levels from the lower thoracic region to the base of the skull, named in ascending order: semispinalis thoracis, cervicis and capitis:
a. Semispinalis thoracis – extends from the transverse processes of the lower thoracic vertebrae to the spinous processes of the upper thoracic vertebrae (Last 1959, p. 612)

b. Semispinalis cervicis – larger and more powerful than semispinalis thoracis, it originates above and in continuity with it. It is inserted into the spinous processes of the cervical vertebrae including the bifid spinous process of the axis or first cervical vertebra

c. Semispinalis capitis – the most powerful layer of semispinalis, it arises from the transverse processes of the upper thoracic and the articular processes of the lower cervical vertebrae and is inserted into the base of the skull around the midline of the occipital bone.

image Levatores costarum: these are small, strong, triangular muscle pairs, 12 in number, found between the eleventh thoracic and seventh cervical vertebrae. Each of the 12 pairs descends from the transverse process of the vertebra above to the upper border of the rib below, near its tubercle. The fibres fan out as they pass downwards and laterally (Palastanga et al 2002, p. 481).

This whole middle layer constitutes a greater muscle mass than the deep layer and, together with the muscles of the anterior abdominal wall, makes a major contribution to the stabilization of the entire spine. Multifidus is the particular component thought to play an important role in establishing and maintaining good upright posture. Levatores costarum, on the other hand, is more concerned with assisting the inspiratory muscles of the thoracic ribcage.



Superficial layer – iliocostalis (lateral), longissimus (intermediate) and spinalis (medial)

Sacrospinalis is a collective term for this most superficial of the three layers and is itself subdivided into lateral, intermediate and medial columns lying in parallel. The whole extends from the back of the sacrum and inner edge of the iliac crest to the ribcage. It is a complex arrangement of muscle fibres and bundles, again subdivided into serial sections, of which the detailed origins and insertions are not of specific importance in the context of this manual:


image Iliocostalis: the lateral column has three sections ascending in series: iliocostalis lumborum, thoracis and cervicis.

image Longissimus: the intermediate and strongest column similarly has three sections: longissimus thoracis, cervicis and capitis.

image Spinalis: is the relatively insignificant medial column, subdivided into spinalis thoracis, cervicis and capitis, of which spinalis thoracis is the most clearly defined. Spinalis cervicis and capitis are small, poorly defined and are frequently merged with adjacent sacrospinalis muscle columns.

All these long muscles of the back, together with those of the pelvic floor, the gluteal muscles, the adductors of the thigh and the muscles of the torso all help the erector spinae to stabilize the vertebral column and so provide the foundation of safe, effective movement of the whole body.



Body mass and centre of gravity


The centre of mass of an object is defined as the point about which the mass is evenly distributed and this definition cannot easily be applied to the irregularly shaped human body. However, by first considering the mass of the whole body and then assessing the percentage that the head, neck, trunk, upper and lower limbs individually contribute, allows an approximation of where the centre of gravity would lie when the body is standing upright (Table 1.1).


Table 1.1 Mass of each body segment in percentage of total body mass




































Segment % of body mass
Trunk 49.7
Head and neck 8.1
Upper arm 2.8 each
Lower arm 1.6 each
Hand 0.6 each
Total arm 5.0 each
Upper leg 10.0 each
Lower leg 4.7 each
Foot 1.4 each
Total leg 16.1 each

Reproduced with permission from Palastanga et al (2002).


This is said to be approximately at the level of the second sacral vertebra within the pelvis but shifts according to body and limb movements. For example, flexing the shoulders and reaching both arms forward shifts the orientation of the body’s centre of gravity relative to its base of support.



Base of support


Any part of an object in contact with a surface that is, therefore, supporting it is described as its base of support. This can alter and depends on whether the object is static or in motion and, where the human body is concerned, will depend on the specific posture adapted at any particular time. For example, when standing upright both feet provide the base of support, but during walking, the base of support shifts from one foot to the other as each step is taken. When moving from standing to lying supine, the base of support is increased as more of the body is supported on a surface and, when moving from lying supine to four-point kneeling, the base of support is decreased as the whole of the body weight is supported by the hands, lower legs and feet.



Line of gravity


In the ideal upright static posture the line of gravity is described as a perpendicular line falling through the middle of the body’s centre of gravity. When a body is viewed from the side it is imagined falling through the middle of the external auditory meatus, slightly in front of the shoulder joint, just behind the axis of the hip joint, in front of both the knee and ankle joints and just in front of the heel bone. When a body is viewed from in front or behind, the line divides the body into two equal parts and falls between the feet.


During postural assessment, observing the line of gravity is useful in that it defines ideal static alignment and confirms the enormous variations in human posture; however, it should be realized that it will not necessarily identify underlying biomechanical faults.



Centre of pressure


There is a force reflected from the ground as a result of the action of the body’s weight onto the ground. The centre of this reflected force is described as the centre of pressure and, in the upright stance, it lies within the body’s base of support.



Balance and stability


A body’s shape, mass and orientation in relation to the surface area, shape and position of its base of support determines where both its centre and line of gravity will lie (Fig. 1.11). All these factors contribute to overall balance and stability.


image

Figure 1.11 During quiet upright standing the contact area with the floor underneath the feet and the area in between the feet is the base of support (BOS). Because people cannot easily move their line of gravity to the outer edges of the BOS, the stability limit has been defined as the area within which people can move their line of gravity without losing balance. The centre of pressure (COP) of the ground reaction force is located well within those two areas. Because a person will always sway a bit, the COP oscillates with a certain amplitude.


Reproduced with permission from Trew & Everett (2005).


A stable body will have a stable centre of gravity lying sufficiently low above its base of support to ensure this. Additionally, its line of gravity should fall through the centre of pressure to lie within the base of support.


A stable body will be able to maintain both its centre and line of gravity whilst resisting a short duration of applied force, or will be able to be displaced by an applied force of short duration and yet return to its original, balanced position.


Conversely, an unstable body will lose both its centre and line of gravity when a force of short duration is applied, and will then continue to lose balance as it is further displaced so as to become subject to the influence of gravity.



POSTURAL OBSERVATIONAL SKILLS AND ASSESSMENT


As all individuals have unique anatomical profiles it is difficult to identify definitive attributes for describing normal posture. However, it is possible to identify the components of ideal alignment and posture and these are the standards used for observing and assessing the many postural variations that may be encountered.


Before assessing posture, personal details such as age, sex, medical history, psychological status and adaptive influences, such as occupation, lifestyle, etc., should be noted.



Body types


Classifying body type can also be helpful as inherent characteristics are commonly associated with specific postural faults. These underlying factors will also predetermine the outcome of an exercise programme for a particular person.


For example, a tall, slim individual with naturally poor muscle tone (ectomorph) may be inclined towards having a sway back or exaggerated kyphotic posture and be resistant to building and maintaining muscular strength. Although carefully designed exercise programmes may improve muscle tone and endurance, this would be lost without ongoing training.


The basic anthropometrics classifications are as follows:


image Endomorphs are inclined to be pear shaped with comparatively shorter limbs and extra subcutaneous fat around the hips and thighs.

image Ectomorphs tend to have slender, lean bodies with comparatively poor muscular development, do not gain body weight easily and may even be underweight.

image Mesomorphs have strong athletic bodies with broad shoulders and comparatively narrow hips and need regular exercise to maintain their musculature and prevent loss of muscle tone and weight gain.


Assessment procedures



Assessment of static standing posture


To begin, ask the subject to stand with the feet bare and approximately 8 cm apart (the examiner can place one foot between the subject’s feet to achieve this correct position) and the body weight distributed evenly between the feet.


Considering the fall of the plumb line, observe posture from the side and back (initially one might use a plumb line but with experience exercise teachers learn to imagine such a line) and note the surface markings and underlying anatomical structures that would normally coincide with the plumb line as shown in ‘Ideal alignment side view’ and ‘Ideal alignment back view’. Record any deviations from ideal alignment and note the overall balance of the whole body over the lower limbs and feet.


Next scan the body from the feet up to the head to identify obvious features associated with common postural faults such as flat feet, foot pronation or supination, bow legs or knock knees, exaggerated spinal curves or a forward-poking chin, etc.


Continue with a more careful study of segmental alignment beginning with the head, spine, pectoral girdle and upper limbs followed by the pelvis, hips, lower limbs and feet using the landmarks described in the following charts as guidelines.


Compare deviations from an ideal alignment with those identified as features of common postural faults to confirm specific problems and how to address them.


This same process is used to identify and address faults that occur during sitting, when moving from sitting to standing, and when mobilizing the spine.


Exercises to improve spine mobility should aim to provide continuous support for the intrinsic spinal structures whilst moving each vertebral joint through its optimum range of movement (see Chapter 4).



Assessment of sitting


This might also be formally assessed to confirm the effects that adaptive influences and habits have on a particular person.


To begin, ask the subject to sit on a chair or firm bed that allows the feet to rest on the floor with the upper thighs fully supported and the backs of the knees unrestricted. The feet are positioned approximately hip distance apart.


Scan the body from the feet up to the head to identify habits such as slouching with excessive rounding of the thoracic spine as well as other features associated with common postural faults – a forward-poking chin, incorrect pectoral girdle and pelvic alignment, foot pronation or supination, etc.



Ideal sitting posture


In correct sitting posture the body weight is adjusted to balance over the ischial tuberosities so that, together with the thighs, they provide a stable base of support (Fig. 1.12). The knees are flexed approximately 90 degrees and the lower legs are perpendicular, with the heels aligned with the backs of the knees.


image

Figure 1.12 A backrest or cushion behind your low back helps to straighten it.


Redrawn with permission from Oliver (1999).


The lumbar spine is in approximately mid flexion with the lordotic curve intact but slightly reduced in comparison with standing, and the soft supporting structures in the lower back should appear comparatively relaxed. The whole spine is lengthened, with the crown of the head reaching towards the ceiling and the upper torso balanced above the pelvis. The position may be actively supported by gentle pelvic floor and lower abdominal muscle activation but ideally is maintained without conscious muscular effort.



Ideal supported sitting position


In ideal supported sitting the whole length of the spine rests against a firm surface that inclines very slightly backwards from the perpendicular.



Moving from sitting to standing


When moving from sitting to standing the knees are flexed between 90 and 110 degrees so that the feet lie directly below or slightly behind the knee joint. The spine remains stable whilst the hips increase flexion to about 55 degrees from the upright sitting position to move the body and its centre of gravity slightly in front of the ankle joints. Still seated, the shoulder joints flex up to around 50 degrees, bringing the arms and therefore the body’s centre of gravity further in front of the ankle joints to lift the buttocks from the seat. As the body’s weight is transferred from the seat to the legs, the hips and knees may extend slightly but still remain in flexion. At this stage the ankles are dorsiflexed to their maximum so the dorsiflexors as well as gluteus maximus and the hamstrings are strongly active.


Once the body’s centre of gravity is well established over the feet, the hips and knees simultaneously begin extending and, as extension progresses, the trunk moves more vertically towards the upright position. At the same time plantarflexor activity at the ankle assists hip and knee extension, and slight cervical spine flexion occurs to ensure that the skull balances correctly on top of the spine. Hip, knee and trunk extension continue until standing is achieved.



Assessment of forward bending



Normal


Forward bending from a standing position is the most common movement occurring in daily activities. It begins with the pelvis swaying backwards as the hips flex, so allowing the body to remain balanced over its base of support. Ideally, during this initial hip flexion, the lumbar spine also begins to move into flexion, but only slightly. However, there are normal variations in movement patterns, especially in relation to gender, with men tending to flex more easily in the lumbar spine and women more so in the hips. Even so, the correctly functioning lumbar spine should still not have moved through more than 50% of its total range of flexion.


To progress forward bending, the lumbar spine continues to reduce its lordosis until the curve has just flattened. Once this has occurred, hip flexion continues the motion to the end of the range of forward bending. Ideally, the alignment at that stage should have remained balanced over the feet with the knees passively extended and with no exaggerated swaying back at the ankles, knees or hips. The hips will then be flexed by approximately 70–80 degrees, the lumbar spine just flattened and the thoracic spine forming a lengthened, gentle and smooth curve (Palastanga et al 2002, p. 58).



Variations in alignment at the end of forward bending



image Limited hip flexion causing lower thoracic spine flexion with a backwards sway of the hips, as may occur in individuals with a trunk that is long in relation to the lower limbs.

image Normal hip flexion (70–80 degrees) with a flattened lumbar spine but with excessive thoracic flexion, as may occur in individuals with impaired segmental spine mobility.

image Normal hip flexion but with the lumbar spine curve being actually reversed as opposed to only flattened, as may occur in individuals with a trunk that is short in relation to their lower limbs.

image Limited hip and spine flexion and with an exaggerated swaying back of the ankles, knees and hips, as may occur in individuals with restricted spine mobility and short or tight calf musculature, particularly gastrocnemius.

image Excessive lumbar flexion, as may occur in individuals with a flat back posture. The normal range of lumbar flexion is no more than approximately 50 degrees, and when moving into flexion from the normal lordotic position the first 20–35 degrees will only bring the lumbar spine into a neutral position, thereby allowing a further 15–20 degrees of lumbar flexion during forward bending. When an individual with a flat back posture flexes the lumbar spine from a neutral position, 50 degrees of lumbar flexion can still occur during forward bending. This could allow the lumbar spine a degree of flexion outside its safe anatomical range which might damage ligaments and other soft supporting structures at the back of the spine.


Assessment of return from forward bending



Normal


When returning from forward bending the initial part of the motion is hip extension, and then the hips and spine extend concurrently and smoothly, with the vertebral segments mobilizing in sequence to return to the upright position. A correct movement pattern demonstrates combined lumbar spine and hip extension, and, as the hips have the greatest overall range of movement, they can be seen to move the most. Once the upright position is achieved, the normal spinal curves are re-established to balance the body correctly over the lower limbs and feet (Palastanga et al 2002, p. 60).



Common faults in movement sequencing during flexion and return from flexion



During flexion:


image More than 50% of the total range of lumbar flexion occurring before the initiation of hip flexion occurs in individuals with excessive lumbar spine mobility and restricted segmental movement in other areas of the spine and who commonly have associated low back pain.

image Failure of each segment of the vertebral column to contribute its optimum range of movement can be found in individuals with exaggerated spinal curves or where pathology or pain limits overall mobility. Some segments may then become hypermobile whilst others become correspondingly hypomobile.

image Lumbar flexion greater than 25–30 degrees at the end of forward flexion is a feature in some individuals with low back pain associated with excessive lumbar spine mobility and restricted movement in other areas of the spine.

image An exaggerated swaying back of the hips and ankles with restricted hip and spine flexion, as may be associated with calf muscle tightness and reduced spine mobility.

image Exaggerated thoracic spine flexion, limited hip flexion and bent knees towards the end of forward bending, as may be found in individuals with a trunk that is long relative to the lower limbs or in those with inflexible gluteal, hamstring or calf muscles.


During return from flexion:


image The motion initiates in, or is confined more to, the lumbar spine soon after the hips begin to extend, as may occur in individuals who have low back pain caused by extension, or who habitually use the lumbar spine rather the hips when performing everyday activities.

image During the motion the hips and ankles sway forwards markedly to reduce the load on the hips as found in those with swayback posture and weak hip flexors.

image The motion initiates in and remains confined more to the hips with minimal spine mobilization as found in individuals such as gymnasts who repeatedly hyperextend the lumbar spine and who possibly have strong, tight anterior abdominal wall muscles that may limit thoracic spine mobility.

image Failure of each segment of the vertebral column to contribute its optimum range of movement can be found in individuals with exaggerated spinal curves or where pathology or pain limits overall mobility. Some segments may then become hypermobile whilst others become correspondingly hypomobile. This can contribute to low back pain.


Assessment of lateral flexion or side bending



Normal


The total range of side bending motion may be greater than 75 degrees depending on the number of mobile thoracic spine segments involved. Movement occurs most freely in the lower segments of the thoracic spine (approximately 8–10 degrees per segment) where the ribs do not restrict side bending. In the other thoracic and the lumbar spine segments side bending is comparatively restricted (approximately 6 degrees per segment) but fairly evenly distributed between them; however, at the lumbosacral junction only about 3 degrees of lateral movement is possible.


During side bending the lateral movement of the vertebral segments occurs concurrently with rotation. When the spine flexes to the right the thoracic vertebrae rotate to the right and the lumbar vertebrae rotate to the left; this coupling action results in restricted lateral flexion to the right, reducing spine mobility during rotation to the left, and vice versa.


When assessing side bending, the lumbar spine should appear to curve smoothly and gently from just above the lumbosacral junction, and this curve blends into a more obvious lateral curve along the lower thoracic spinal segments. The lower thoracic curve continues upwards as a more gentle curve formed by middle and upper spine segments so that, as the body folds over the iliac crest, the spine forms a lengthened, smooth, C-shape.



Observable faults during the side bending motion



During side bending to the right:


image Failure of each segment of the vertebral column to contribute its optimum range of movement can be found in individuals with exaggerated spinal curves or where pathology or pain limits overall mobility. Some segments may then become hypermobile whilst others become correspondingly hypomobile. This can contribute to low back pain.

image Lumbar spine straightness as found in those individuals with very well-developed paraspinal muscles, the stiffness of which might inhibit lumbar vertebral movement, so that during side flexion the lumbar spine remains straight apart from one axis of rotation towards its base at the lumbosacral junction.

image To assess and correct this, the teacher may support the subject at the level of the iliac crest to stabilize the pelvis before side flexion and then cue for the lower ribs to be drawn in towards the waist on the side of flexion. If the above measures correct the problem, and the lumbar spine then curves during side flexion, the lumbar paraspinal muscles are probably stiff but not necessarily shortened.

image Lumbar spine straightness may also result from tensor fasciae latae tightness that may restrict lumbar spine mobility when side bending to the opposite side.

image Restricted side bending movement to one side, with comparatively free side bending to the other, can be attributed to the postural rotation of spinal segments occurring in conditions such as scoliosis. Should the spine habitually rotate to the right during side bending, its rotation to the left is limited, so restricting side bending to the right. Conversely, as the spine is already rotated to the right, side bending to the left is relatively free.


Assessment of spine rotation


The thoracic spine allows approximately 35 degrees of rotation in each direction, the lumbar spine approximately 13 degrees and at the lumbosacral junction there is normally about 5 degrees of motion, making it the most mobile single junction. The thoracic spine is where spine rotation should mostly occur, as the shape and orientation of each thoracic vertebra allow an optimum range of movement for each spinal segment. The lumbar spine and the lumbosacral junction are prone to injuries caused by excessive, repetitive rotary motions with the lumbar spine flexed, and therefore should be comparatively immobile during spine rotation (Tables 1.2 & 1.3).


Table 1.2 Summary of ideal movement during bending forwards and returning from bending forwards





















Movement sequencing into forward bending Movement sequencing to return from forward flexion

1 The pelvis sways slightly backwards and the hips begin to flex to initiate forward bending
1 The hips extend to initiate the return from forward bending

2 The lumbar spine begins to reduce its curve to progress forward bending
2 The hips and spine extend concurrently, with the hips moving more than the spine to continue the motion

3 The lumbar spine continues to reverse its curve until it begins to flatten to and further progress forward bending
3 The hips and spine extend concurrently, with the hips moving more than the spine to continue the motion

4 The lumbar spine flattens and the movement continues as hip flexion to and further the end range of motion
4 The hips and spine extend concurrently, with the hips moving more than the spine to continue the motion

5 The lumbar spine has flattened, the hips are flexed approximately 70–80 degrees and the thoracic spine forms a lengthened, gentle curve at the end of the motion
5 The lumbar lordosis is re-established to return to a correctly aligned and balanced upright posture at the end of the motion

Table 1.3 Summary of ideal movement during spine lateral flexion and rotation*












Lateral flexion Rotation

1 The greatest range of motion is in the lower thoracic spine. The whole thoracic spine has a total range of movement greater than 75 degrees (the whole spine should form a smooth continuous curve)

As the spine flexes to the right the thoracic vertebrae rotate to the right
1 The movement initiates in the thoracic spine (the movement should be cued to occur from above the waist, e.g. for ‘rotate the chest’)

2 The range of motion in the lumbar spine (L1–S1) is approximately 27 degrees. The range of motion at the lumbosacral junction is approximately 3 degrees (the lumbar segments should form a smooth continuous curve)

As the spine flexes to the right the lumbar vertebrae rotate to the left
2 As the motion continues it should be confined more to the thoracic spine

* Based on data from Bobath (1978), Larson & Gould (1974), Sahrmann (2002), White 1969, White & Panjabi (1978).



Ideal alignment



Static postural observation from the side


In this position the imaginary plumb line represents the postural line of gravity and facilitates the observation of relative symmetry in the sagittal plane. Beginning with the spine, observe in relation to the plumb line the positions of the head, tips of the shoulders, hip and knee joints, and note unnecessary tension in associated muscles and soft tissue (Figs 1.13–1.15).


image

Figure 1.13 A line projected through the centre of gravity onto the floor is called the line of gravity. In the picture this line is shown on a person standing ideally upright. Some anatomical landmarks give a better indication of where the line is located.


Reproduced with permission from Trew & Everett (2005).


image

Figure 1.14 Ideal alignment side view: the subject stands upright in bare feet placed slightly apart to be directly below the hip joints. The feet are facing forward and parallel with each other. The knees are straight but relaxed, the arms hang freely so that the hands are just in front of the hips. The eyes look straight ahead and both hips and shoulders are unrotated.


Reproduced with permission from Trew & Everett (2005).


image

Figure 1.15 Postural alignment must be seen in regard to the force of gravity which seeks constantly to pull us down. A subject exhibiting ideal posture will feel an overall sense of well-being. With their postural muscles working effectively they will have a sense of ease and lightness and their muscle tone will be normal, unstrained and unstretched.


Reproduced with permission from Trew & Everett (2005).


When observing the lower legs and feet, note whether the line of gravity falls approximately through the lateral malleolus as well as the state of the knee joints and leg muscles which should appear comparatively relaxed. Also note the tone and development of the hamstring and gluteal muscles in relation to one another.

Related posts:

The teaching process Health and safety Anatomy review – the upper limb Anatomy review – the torso, lower limbs and feet Exercises for core stabilization and efficient movement Common medical conditions and problems

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Sep 12, 2016 | Posted by in MANUAL THERAPIST | Comments Off on Good posture and how it can be achieved

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