erc bio mechanics and posture

8/3/2019 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.

erc bio mechanics and posture

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