ERC Bio Mechanics and Posture
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Transcript of ERC Bio Mechanics and Posture
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Fitnation Exercise Rehabilitation Certificate 1.5 1
BIOMECHANICS
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Biomechanics
Definition
The area of study where the knowledge and methods of mechanics are
applied to the structure and function of the human body.
What is the Purpose of Biomechanics?
The internal and external forces acting on a human body determine how the
parts of the body move during performance of a motor skill. Biomechanics
provides a sound logical basis upon which to evaluate various techniques that
might be used.
Basic Concepts of Human Skeletal Articulations
The body is generally seen as a series of rigid segments connected by joints.
The joints largely determine the directional motion capabilities of the body.
Also, the anatomical structure of a joint varies little from person to person. The
variations in joint ranges occur due to differences in tightness and laxity of the
surrounding soft tissues.
Joint Stability
Joint stability refers to the ability of a joint to resist dislocation.
Factors that affect joint stability:
Shape of articulating surfaces
Congruence (closeness) of the articulating surfaces
These surfaces are often not symmetrical and there is often one
position of best fit in which the area of contact is maximal. This is called
a closed packed position. Any movement away from this position
results in a reduced area of contact known as a loose packed position.
Slight variations in shapes and sizes of the articulating bone surfaces
occur in individuals.
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Arrangement of ligaments and muscles:
Ligaments, muscles and muscle tendons affect the relative stability of joints.
Strong ligaments and tendons often increase joint stability (eg the knee joint).
Tension in muscles is divided into:
Rotary component: - muscle tension perpendicular to the long axis of
the attached bone contributes to rotation.
Stabilising component: - line of force is angled towards the joint centre.
Dislocating component - line of the muscle is angled away from the
joint centre.
Joint Flexibility
This refers to range of motion and is joint specific. Factors influencing joint
flexibility include:
Shapes of articulating bone surfaces
Intervening muscle and fat
In most individuals, range of movement is determined by laxity of
tissues crossing the joint.
Research shows that risk of injury is increased when joint flexibility is:
Extremely low
Extremely high
When theres significant imbalances on sides of the body
Biomechanics of the Upper Extremity Shoulder
Movements of the shoulder joint:
Movement of the humerus commonly involves actions within four joints
(glenohumeral, scapulothoracic, acromioclavicular (AC) andsternoclavicular)
As the arm is elevated in both abduction and flexion, the rotation of the
scapula assists in increasing the total range of motion
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Although the positions of the humerus and scapula vary during
movements, a general pattern exists. This is called the scapula-
humeral rhythm.
In the first 30 degrees, contribution of the scapula is only a fifth that of
the glenohumeral joint. Beyond 30 degrees, the scapula rotates one
degree for every 2 degrees of humeral movement. This enables a
greater range of motion at the shoulder.
Loads on the Shoulder:
All of the bones making up the shoulder joint act as one unit. However, as the
glenohumeral joint provides direct mechanical support for the arm, it sustains
greater loads.
The arm only accounts for 5% of body weight, but when the arm is extended
horizontally, the weight of the arm increases the torque of the joint. The
muscles around the region must contract to support the extended arm. This
results in compressive forces at the glenohumeral joint of up to 50% of body
weight.
Biomechanics of the Lower Extremity - Hip
The shoulder is suited to activities requiring a large range of movement
whereas the hip is well suited to the functions of weight bearing and
locomotion.
Movements of the Hip:
Flexion
Extension
Abduction
Adduction
Medial and lateral rotation
Horizontal abduction and adduction
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Loads on the hip:
The hip is the major weight bearing joint of the body. When the body weight is
evenly distributed across both legs, the weight at each hip is one half the
weight of the body segments above the hip or one third of total body weight.
The weight at each hip is approximately the same as body weight during the
swing phase of walking. During the support phase at normal walking speed,
peak forces can range from 300 - 400% of body weight and 550% during fast
walking and jogging and up to 870% during stumbling. The use of a cane or
crutch on the side of an injured hip is beneficial as it serves to more evenly
distribute the load on the hips during the gait cycle.
Biomechanics of the Lower Extremity Knee
Movements at the knee:
Flexion and extension
Rotation (slight)
Passive abduction and adduction
Loads on the knee:
The knee is a weight bearing joint that is positioned between two of the
longest bones in the body, therefore potential to develop torque is large.
Tibiofemoral Joint
The compression forces at this joint are reported to be greater than 3 times
body weight during stance phase and 4 times during stair climbing. The
medial tibial plateau bears most of the load during stance when the knee is
extended. The medial plateau has a joint surface 60% larger than that of the
lateral plateau.
Menisci act to distribute the loads over a broader area, thus reducing the
magnitude of joint stress. Menisci also act to assist in force dissipation at the
knee, bearing as much as 45% of the total load.
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As knee flexion occurs, and the angle at the joint increases to 90 degrees the
shear forces increase. These are the forces which draw the tibia forwards or
backwards relative to the femur. They are resisted by the ligaments and
tendons crossing the knee. These structures are placed under differing
degrees of stress during full squats involving deep knee bends. Therefore for
some clients, these movements should be avoided.
Patellofemoral Joint
Compressive forces are approximately half body weight during normal
walking gait, increasing to over three times during stair climbing.
Patellofemoral forces increase with knee flexion during weight bearing
due to increased compressive forces and a larger amount of quad
tension required to prevent knee from buckling against gravity. The
squat produces 7.6 times body weight compressive forces and, given
the small surface of the patella, the transmitted stress is high.
Lower Extremity Postures
The tightness or laxity of ligaments, as well as the relative strengths and
weaknesses of muscles produce lower extremity postures that are unique to
each individual.
Ideal Alignments of Body Segments
This is discussed in further detail in the next section on posture.
Generally, normal alignment does not necessarily mean ideal alignment. What
is normal is a measure of what occurs on the average, not necessarily an
ideal measure. In fact, most people do not have ideal alignments for one
reason or another.
For example, the ideal alignment of the legs is likened to that of a column that
supports a roof. Such a column should be as straight and as vertical as
possible. However, in reality the alignment of the femur is largely dependent
on hip width; wider hips result in a greater angle of the femur.
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Principles of Posture and Functional Movement
The term posture is used to describe the alignment of the skeletal system
when stationery or moving. It is called static and dynamic posture,
respectively.
Regular exercise helps to maintain the balance between strength and range
of movement of muscles. However, there are a number of factors that can
upset postural balance. These factors include:
Biomechanics changes due to injury
Poor seated posture
Poor ergonomics during work
Disuse
Training in poor movement patterns
Over training
Poor posture can be quite detrimental to health as it contributes to inefficient
movement and places additional stress on the organs and systems of the
body.
As a Personal Trainer you may not be able to fix all of your clients postural
issues, however it is still important that you analyse each client separately and
assess their movement patterns to ensure you do not prescribe exercises to
exacerbate postural imbalances. There are also some simple principals that
Personal Trainers can follow to help correct muscle imbalances.
Personal trainers need to have an awareness of:
The characteristics of good posture static and dynamic
Common postural problems
Exercises and cues that may assist in correcting postural problems
Note there are some postural conditions that occur because of structural
deformities. For example, the spinal condition known as scoliosis is usually
due to a structural problem within the vertebra rather than any muscle
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imbalances. Therefore it is difficult to provide exercises that will correct the
problem.
It is recommended that trainers assess the posture of clients either through a
structured assessment or by observing dynamic posture throughout
movement.
The following section of the manual provides information on postural
conditions and exercises that may be used to correct them.
Assessment Guidelines
Assessment of basic posture should be done in a format that has practical
application to the individuals circumstances. For example an elite gymnast
has different types of postural requirements than someone in a sedentary
office position.
It should be emphasized that posture is often related to habits and by
providing cues or signals to modify the habit it is possible to amend the
posture. The personal trainer should regularly provide postural cues when the
client is performing exercise to reinforce the correct movement pattern and
body position.
By making gradual, small changes to the individuals average work day or
training day, permanent improvements will occur.
Static Assessment
To assess static posture:
Explain to your client you are going to have a look at their posture so
that you can provide a program tailored to their needs
Have the client stand in a normal, relaxed stance with arms by their
side.
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Observe the client from a variety of angles; anteriorly, posteriorly and
laterally
For the clearest observation, the client would be wearing minimal
clothing (shorts and singlet top).
Lateral View
Correct standing posture when viewed laterally is as follows. A vertical line
would pass:
through the middle of the ear
slightly anterior to the point of the shoulder
through the middle of the head of the femur at the hip joint
slightly anterior to the middle of the knee
through the lateral malleolus of the fibula
Lateral View Anterior View Posterior View
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Anterior and Posterior View
When viewed anteriorly or posteriorly, a vertical line would pass directly
through the mid-line of the body dividing it symmetrically into left and right
sides.
Horizontal lines should pass through:
The left and right acromion process (point of the shoulder)
Left and right anterior and posterior superior iliac spines (top of the
hips)
Left and right patella (knee caps)
Note, the Achilles tendon should essentially be vertical
Be mindful that some clients when asked to stand for a static posture
assessment will not stand naturally they will assume a stance with good
posture. Therefore it is important you observe your client throughout
movement as well because you will pick up on postural deficiencies not
identified in the static assessment.
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Common Postural Problems
The following tables outline:
common postural deficiencies
how they can be identified
the cause of the condition
exercises affected by the condition
corrective exercises
Condition /
Characteristics
Hanging or protruding head the head and neck
protruding forward rather than directly above the shoulders
Demonstration
Cause Weak neck extensors (Semispinalis, Splenius)
Osteoarthritis or osteoporosis in the cervical spine
Exercises to be
avoided (or
careful with)
Shoulder press
Push press
(generally, all overhead movements)
Corrective
Exercises
Back extension with head in a neutral position to
strengthen neck extensors
Stretching of neck flexors through controlled
extension / hyperextension
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Condition /
Characteristics
Rounded Shoulder (Protracted Shoulders) and
Kyphosis in this condition the shoulders are medially
(internally) rotated and protracted (protruding forward).
Kyphosis is often associated with rounded shoulders. It is
an exaggerated (kyphotic) curve in the thoracic spine. In
serious cases, it appears as a hump or lump.
Demonstration
Cause Tightness in pectoralis major and pectoralis minor
Weakness in posterior deltoid, trapezius, serratus
anterior and thoracic extensors (including Spinalis
Dorsi and Longissimus Dorsi)
Poor shoulder stability-weak rotator cuff muscles
Exercises to be
avoided (or
careful with)
Shoulder press
Push press
Seated Triceps Extension
Push up
Front raises (generally, all overhead movements)
Corrective
Exercises
Seated row
Single arm cable rows
One arm dumbbell row
Bent over row
Stretching of pectoralis major and minor, anterior
deltoids (eg. door frame stretch)
Scapula push ups (on all fours)
Focus on retraction of the scapula during
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movements (keep the shoulders back)
Condition /
Characteristics
Winged scapula
The correct position of the scapula is when it sits flat
against the ribs. In this condition, the medial border and
inferior angle of the scapula flares away from the ribs. The
condition is often present in adolescent males who have
yet to develop strength in muscles such as the rhomboids
which assist in holding the scapula flat.
It is also common in people with poor control through their
scapula stabilisers such as serratus anterior.
Demonstration
Neutral Scapula Winged Scapula
Cause Weakness in rhomboids, serratus anterior and
subscapularis
Exercises to be
avoided (or
careful with)
Shoulder press
Push up
Lat pulldown
Dumbbell pull over
External rotation movements
Corrective
Exercises
Seated row
Single arm row (theraband) One arm dumbbell row
Shoulder girdle retraction (on all fours)
Stretching of pectoralis major, anterior deltoids (eg.
door frame stretch)
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Focus on maintaining the scapula in a retracted
position throughout the movement
Condition /
Characteristics
Lordosis
It is an exaggerated lordotic curve in the lumbar spine.
This is a common condition that produces a sway back
appearance. It is associated with an anterior pelvic tilt
(the top of the pelvis is tilted forwards).
Demonstration
Cause Tightness in iliopsoas (hip flexor) and erector
spinae
Weak abdominals (rectus abdominis and
transverse abdominis)
Exercises to be
avoided (or careful
with)
Overhead movements in a standing position may
exacerbate the condition.
Shoulder press (standing)
Squat
Note; it is ok for the client to perform a squat, but
it must be with a neutral spine stop the squat if
the correct pelvic position is not maintained
Corrective
Exercises
Kneeling hip flexor stretch
Lower back stretch (for erector spinae)
Abdominal bracing, sit ups, crunches to
strengthen abdominals
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Bridging (eg.using a swissball)
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Condition /
Characteristics
Anterior Pelvic Tilt
The condition is often associated with lumbar lordosis.
The pelvis is tilted anteriorly which results in the ischial
tuberosity (attachment for the hamstrings) moving
superiorly and posteriorly. It causes increased tension
within the hamstrings because they are in a permanently
stretched position.
Anterior pelvic tilt causes strain on the lumbar
apophyseal joints (between vertebra) and sacroiliac
joints.
It is common to have a slight anterior pelvic tilt however
an excessive anterior tilt is determined by the ASIS beingsignificantly lower than the PSIS.
Demonstration
Cause Weak abdominals and hamstrings
Tightness in lower back (erector spinae), iliopsoas
and rectus femoris
Causes tightness in hamstrings because they are
permanently stretched
Exercises to be
avoided (or
careful with)
Overhead movements in a standing position may
exacerbate the condition.
Squat
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Hack squat
Shoulder press (standing)
Knee extension movements due to tight
hamstrings (including running and kicking)
Forces on the knee can also be greater than
normal during foot strike in walking / running. The
increased eccentric loading on the knee can lead
to patella tendon injury.
Corrective
Exercises
Kneeling hip flexor stretch
Lower back stretch (for erector spinae)
Quadriceps stretch (specifically to stretch rectus
femoris)
Hamstring stretch and strengthen
Abdominal bracing, sit ups, crunches to strengthen
abdominals
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Condition /
Characteristics
Posterior Pelvic Tilt
The condition is sometimes called flat back because
there is a reduction in the lumbar lordotic curve.
The pelvis is tilted posteriorly which has the effect of
pushing the hips forward.
It is identified when the ASIS is higher than the PSIS
as viewed from the side.
Demonstration
Cause Weak iliopsoas
Tight abdominals and gluteus maximus
(causing hip extension / hyperextension)
Shortened hamstrings
Exercises to be
avoided (or careful
with)
Leg Press
Squat
Deadlift
Hip flexion movements due to weakness in
iliopsoas (including running and kicking)
Corrective Exercises Hamstring stretch
Gluteal stretch
Abdominal stretch
Hip flexor exercises (for strength)
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Condition /
Characteristics
Pelvic Lateral Tilt
Poor control of the hip abductors and adductors
allows the contra-lateral hip to drop during the swing
phase in walking and running leading to excessive
lateral tilt.
It causes tightness in the hip rotators (such as
piriformis) and increased tension within the tensor
fasciae latae, and iliotibial band. Often it is a major
contributor to knee injuries (including patellar tracking
syndrome).
To assess for pelvic lateral tilt, locate the right and
left anterior superior iliac spines to check they are
level.
Demonstration
Cause Imbalances (weakness or tightness) in
adductors and abductors (gluteus medius)
Tightness in quadratus lumborum (either right
or left side)
May also be caused by structural
abnormalities such as leg length inequalities.
Exercises to be
avoided (or careful
with)
Walking
Running
Squats
Lunges
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Corrective Exercises Hip adduction or abduction exercises
Stretching of hip abductors and adductors
Stretching of quadratus lumborum
One legged squats focusing on pelvic control
and maintaining knee and ankle alignment. No
hip drop on opposing side
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Condition /
Characteristics
Scoliosis
Scoliosis is characterised by a C or S shaped curve in the
spine when viewed posteriorly. The curve may occur along
the length of the spine from the cervical to the lumbar region.Demonstration
Cause
Usually caused by a structural condition, osteoarthritis,osteoporosis or poor lifting and carrying habits
May be associated with imbalances in strength and
flexibility of erector spinae, latissimus dorsi, quadratus
lumborum and trapezius specifically between the
right and left sides
Exercises
Affected by the
Condition
Dependent on the severity of the condition may impact
on most movements, particularly:
Lateral flexion (side bends)
Overhead exercises
Running
Corrective
Exercises
Dependent on the severity of the condition and the
cause
Lateral flexion side bends to stretch and strengthen
and to correct imbalances.
Rotation of the trunk twisting movements to stretch
and strengthen and to correct imbalances
In many cases where there is an underlying structural
problem, exercise cannot be used to correct the
condition.
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Posture and Range of Movement
Good posture enables people to move through a normal range of movement.
The following information clarifies the normal range of movement through
some of the main joints of the body.
Keep in mind some people will have a greater range of movement if they:
regularly perform exercises for flexibility
have bones that are less congruent at the joints (dont fit as snugly)
have ligaments that are slightly lax (dont hold the bones together as
firmly)
Hips
The normal range of movement for the hip is:
120 flexion and 20 extension (in the sagittal plane)
40 abduction and 25 adduction (frontal plane)
45 internal rotation and 45 external rotation (transverse plane)
Normally, there should be no change in the degree of rotation of the hip with
hip flexion or extension.
Knees
The normal range of movement for the knee is:
135-145 flexion and 180 extension - the knee is considered in
neutral position when fully extended.
No hyperextension or abduction / adduction (frontal plane) movement
normally exists.
The fully extended knee has no rotation (transverse plane). When the
knee is flexed at 70-90, up to 45 of rotation may occur.
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Ankle / FootTibia, fibula and talus
The normal range of movement of the ankle joint is:
45 plantar flexion and 10-15 dorsi flexion
10 of ankle dorsi flexion is required for normal walking biomechanics.
Abduction of the foot occurs with dorsi flexion and adduction of the foot
occurs with plantar flexion.
Subtalar joint
The normal range of movement between the talus and calcaneus bones is:
Pronation and supination
Pronation includes eversion, dorsi flexion and abduction of the foot
The calcaneus inverts and everts with subtalar joint motion
The amount of inversion is normally twice that of eversion, with
approximately 20 of inversion possible and approximately 10 of
eversion possible.
Mid tarsal joint
Consists of the calcaneocuboid and the talonavicular joints
The mid tarsal joint has two axes of movement, which are the oblique
and longitudinal axes
The oblique axis allows dorsi flexion and abduction (with pronation)
and plantar flexion and adduction (with supination)
For every 1 of abduction, there is 1 of dorsi flexion and for every 1 of
adduction there is 1 of plantar flexion
The longitudinal axis consists of a small amount of forefoot inversion
and eversion
The range of movement of the mid tarsal joint is dependent on thesubtalar joint
Pronation of the subtalar joint increases the range of movement of the
mid tarsal joint
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Supination of the subtalar joint decreases mid tarsal range of
movement
Metatarsophalangeal joint
The normal range of movement between the toe and foot is:
65-70 dorsi flexion to assist with the push off when walking.
Shoulder
The normal range of movement for the shoulder is:
180 flexion and 60 extension (hyperextension) full extension is the
normal position
180 abduction and 50 adduction (past the midline in the frontal plane)
90 lateral (external) rotation and 70 medial (internal) rotation
Elbow
The normal range of movement for the elbow is:
150 flexion and 0 extension full extension is the normal position
80 pronation and 80 supination
Wrist
The normal range of movement for the wrist is:
80 flexion and 70 extension
Vertebral Column
The normal range of movement for the vertebral column varies between
segments. In total over the 3 segments (cervical, thoracic, lumbar) it is:
110 flexion (when standing) and 25 extension (hyperextension) full
extension is the normal position
90 rotation
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Biomechanics of Movement
The science of analysing range of movement at a joint during movement is
known as biomechanics. If a person has poor biomechanics as they move it
means that:
Their body is not working efficiently
They may be at an increased risk of injury
It is not expected that personal trainers will be able to perform biomechanical
analysis on clients. Generally this requires complex equipment. The personal
trainer should be aware of correct technique and movement patterns and
should carefully observe the clients to ensure this occurs during exercise.
The following section provides information on biomechanical abnormalities
and some of the common injuries associated with them.
Lower Limb Biomechanics
The three main biomechanical abnormalities of the lower limb include:
1. Excessive Pronation
2. Excessive Supination
3. Abnormal Pelvic Movement
Excessive Pronation
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Pronation of the foot occurs at the subtalar joint. Abnormal pronation occurs
when the amount of pronation is excessive or when pronation exists at a
phase in the gait when the foot should be supinating. An excessively
pronated foot may lead to excessive internal rotation of the lower limb during
weight bearing.
Greater demands are therefore placed on the ligaments and muscles of the
foot and lower limb.
Excessive pronation causes increased ground reaction forces on the medial
side of the foot which leads to:
first metatarsophalangeal joint problems such as hallux valgus and
exostoses. corns and callus build up
abnormal flattening of the longitudinal arch of the foot and increased
strain on the plantar fascia and other plantar musculature.
strain on the gastrocnemius and soleus as well as tibialis posterior as
these muscles need to contract harder and for longer to achieve
plantar flexion and supination of the foot. This can lead to tendinitis of
the achilles and posterior tibialis.
increased internal rotation of the tibia, which can then tighten the
iliotibial band.
stress fractures in the tibia and tarsals (particularly the navicular) due
to uneven weight distribution and excessive movement of the
metatarsals during forefoot loading.
Excessive Supination
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Structural foot abnormalities can cause supination of the subtalar joint as the
subtalar joint attempts to correct or compensate for these abnormalities.
Excessive supination can also occur due to weak peroneals or as a result of
spasming or tightness of the tibialis posterior and gastrocnemius or soleus.
Whereas a pronated foot is very unstable, a supinated foot is quite rigid and
stiff. This results in decreased shock absorption during movement. The leads
to:
tibia, fibula, calcaneus and metatarsal stress fractures
lateral instability of the foot and ankle resulting in an increased
incidence of sprains
tightness of the iliotibial band and bursitis at the femoral epicondyle
Pelvic BiomechanicsA certain amount of pelvic rotation, anterior-posterior tilt and lateral tilt is
required during running. Excessive movements in any plane (sagittal, frontal
and transverse) can occur due to poor control of the surrounding stabilising
muscles. Less efficient movement and less effective transmission of forces
through the pelvis may result. Lack of stability in one plane of movement can
affect other planes of movement as well.
The most common abnormalities associated with pelvic movement are:
excessive anterior tilt
excessive lateral tilt
asymmetrical (rotated) pelvis
Excessive Anterior Tilt
Poor muscle control in the abdominals, gluteus medius and minimus,hamstrings and external hip rotators in conjunction with tight hip flexors can
increase the anterior pelvic tilt especially in running. This increases the length
and tension of the hamstrings and abdominal muscles.
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The external rotator muscles need to work harder to provide pelvic stability to
compensate for the reduced contribution of the gluteal muscles. This leads to:
tightening in the external rotators of the hips
Increased lumbar lordosis and strain on the lumbar and sacroiliac joints
Increased forces on the knee causing patella tendon injury
Tightness in hamstrings and increased risk of strain
Excessive Anterior Tilt
Excessive Lateral Tilt
Poor control of the hip abductors and adductors of the weight bearing limbs
allows the contra-lateral (opposite) hip to drop during the swing phase in
walking / running therefore leading to excessive lateral tilt of the hip. This can
lead to:
Tightness and inflammation of the adductors, tensor fasciae latae,
iliotibial band and lumbar spine
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Asymmetrical (rotated) Pelvis
This occurs when the pelvis is twisted or one side is in a position slightly
forward of the opposite side.
It is caused by:
tight / shortened muscles attaching to the pelvis
weakening of the surrounding muscles supporting the pelvis
leg length inequalities, scoliosis and other structural abnormalities
This may occur as an adaptation to a previous injury and can be exacerbated
by running. Osteitis pubis and overuse injuries of the lower limb are often
associated with this condition.
Common Structural Abnormalities
The following information clarifies some common structural problems of the
lower limb that can predispose a client to injury. The personal trainer is not
able to correct the problems because they are structural but may work with
other health professionals such as a podiatrist to assist in the rehabilitation of
the problem.
Genu Valgum (or valgus)
also known as knock knees
causes excessive pronation of the feet, as the centre of gravity is
medial to the subtalar joint.
Genu Varum (or varus) also known as bow legs
causes increased varus heel strike and greater lateral stress on the
knees may lead to the development of patellofemoral pain
excessive pronation of the subtalar joint may result to allow the medial
aspect of the foot to make contact with the ground.
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Genu Valgus Genu Varum
Leg Length Inequalities
Differences in leg length can be structural or functional
Functional differences can occur due to pelvic asymmetry or
asymmetrical pronation or supination (occurring in one foot more than
the other)
The following are signs the client may have leg length differences:
Head tilt and shoulder drop often towards the longer leg
Asymmetry of arm swing including an abducted arm towards the longer
side
Increased elbow flexion and increased speed of arm swing indicating
the pelvis at the opposite side is moving faster
Pelvis is higher on the long limb side
Increased stresses on the short side as more weight is borne through
that side
External rotation of hip, widening the gait to increase support on theshort side
Pronation or supination of one foot
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The following table summarises some of the causes of common lower limb
injuries:
Injury Biomechanical Abnormality
Plantar fasciitis Pronated foot
Achilles tendonitis Pronated foot
Peroneal tendinitis Pronated foot at toe-off phase
Medial shin pain Pronated foot
Patellar tendinitis Pronated footTight quadriceps, hamstrings and calvesAnterior pelvic tilt
Patellofemoral syndrome Pronated footAnterior pelvic tiltVarus alignment of knees
Iliotibial band frictionsyndrome
Pronated footVarus alignment
Hamstring strain Anterior pelvic tilt
Metatarsal stress fractures Pronated foot
Supinated foot
Navicular stress fractures Pronated footVarus alignment
Fibular stress fractures Supinated footPronated footVarus alignment
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Functional Methods of Correcting Posture
Because posture is important in all day to day movements, it is important for
the personal trainer to relate the exercises in the session to those completed
in daily activities.
The term kinaesthetic awareness relates to the control of muscles and
position of the body in space. The ability to control muscles is more important
than how strong they are. By assisting the client to develop kinaesthetic
awareness it will assist them to be more aware of their posture.
There are many side benefits besides the decrease in chronic and acute
injuries. For example:
More efficient energy use throughout the day
Increased concentration span
A greater awareness of self that leads to an earlier and better detection
of dysfunction
Lessened effects of degenerative diseases through aging effects, etc.
Some personal trainers use a static posture assessment (see the template on
the next page) to identify conditions. Others will observe the client as they are
moving and try to pick out postural deficiencies.
From the observations try to select exercises to assist in correcting the
deficiency. Also try to provide the client with tips or cues that will remind them
about their posture while performing day to day activities. If you identify a
postural condition that is particularly severe it is recommended you refer the
client to an appropriate health professional (eg.doctor, podiatrist,
physiotherapist,etc)
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Postural Assessment Chart
View the client in a relaxed standing posture from the front, side and back and mark on
the following record any obvious postural conditions. If the condition is excessive refer
to an appropriately qualified professional.
Head and Neck O normal O protracted cervical spine (hanging head)
Rounded Shoulders O normal O rounded
Scapula O normal O winged
Thoracic Spine O normal O increased kyphosis (rounded upper back)
Lumbar Spine O normal O increased lordosis (sway back)
O decreased lordosis (flattened back)
Vertebral Column O normal O scoliosis (S or C shaped curve)
Pelvis O normal / level O anterior tilt O posterior tilt
O lateral tilt O rotated pelvis
Knees O normal O knees rolled in (valgum) O left O right
O knees rolled out (varum) O left O right
O knees hyperextended O left O right
Feet O normal O foot pronated (flat feet) O left O right
O foot supinated (high arch) O left O right
Other Observations:
_____________________________________________________________________
Corrective exercises:
_____________________________________________________________________
_____________________________________________________________________
Red Flags = Refer On
Do any of the above observations appear excessive? O Yes O No
If yes, identify the condition and who you would refer the client to.
_____________________________________________________________________
___________________________________________________________________
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Exercise Guidelines to Improve Posture
Select appropriate exercises to assist in correcting the identified condition.
Clarify whether the muscle needs to be strengthened, stretched or both.
As the client performs the exercise provide them with feedback on their
performance to reinforce correct technique and posture. For example in a
lat pulldown, you might say Well done because you are keeping your
shoulders down and level throughout the movement.
Emphasize a neutral spine position in the exercise. The spine has natural
curves in each segment a neutral spine refers to the maintenance of the
natural curvature without exaggerating or flattening the curves. A neutral
spine is recommended because it reduces stress on the joints and discs.
Activate the core muscles to control the position of the hips and lower
back. The deeper abdominals (transverse abdominis) are used to stabilise
and support the hips and lower back. By activating these muscles we are
switching them on to ensure they are contracting. It takes practise to be
able to contract these muscles. Some instructors will use cues such as
pretend there is a piece of string from your belly button to your spine.
Pretend you are pulling the string to pull your abdominals back toward
your spine.
If the client is performing an exercise using left and right arms or legs,
ensure each is contributing the same effort to the movement. Also check
to ensure both sides of the body are moving through the same range of
movement.
In some exercises you may be able to emphasize a particular component
of the movement because it has implications for posture. For example, in
a seated row, the final phase of the row is emphasized because it retracts
the scapula and works the rhomboid muscles. These are important
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muscles to strengthen for clients with postural conditions associated with
the scapula (eg. winged scapula).
Scapula push ups are performed by protracting the scapula in the push
phase and retracting the scapula in the lower phase. Ensure lumbar spine
remains neutral throughout.
In any push or pull exercise, ensure the arms work at an even height
throughout the movement.
One leg squats are useful for developing core control. Activate the core
muscles to support the lower back and hips. Ensure the hip, knee and
ankle are always aligned during the movement. Try to eliminate side to
side wobble during the movement and dropping of the opposite hip.