Chapter 9
Impaired Posture and Movement
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Impairments In Posture
Basis of many regional musculoskeletal pain
syndromes (MPS).
Regional MPS – Often the result of cumulative
microtrauma.
Microtrauma caused by dysfunctional repeated
movements during ADLs with less than optimal
starting alignment or faulty kinematic motion.
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Pain
Indicates that a mechanical
deformation or chemical process has
stimulated the nociceptors in the
symptomatic structures.
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Underlying Premise
The premise of this chapter is that mechanical stress
related to sustained postures or repeated
movement patterns:
 is the primary cause of pain,
 contributes to recurrence of a painful
condition, and
 is associated with the failure of the condition to
resolve.
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Posture
“Good posture is the state of muscular and skeletal
balance that protects the supporting structures of the
body against injury or progressive deformity irrespective
of the attitude (e.g., erect, lying, stooping, etc.) in which
these structures are working or resting. Under such
conditions, the muscles function most efficiently, and
the optimum positions are afforded for the thoracic and
abdominal organs.”
Committee of the American Academy of Orthopedic
Surgeons.
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Poor Posture
A faulty relationship of the various parts of the
body, which produces increased strain on the
supporting structures and in which there is
less efficient balance of the body over its base of
support.
Posture Committee of the American Academy of Orthopedic Surgeons
(Evanston, IL AAOS;1987:1947:1)
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Standard Posture
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Anatomic and Coincidental Surface
Landmarks
Anatomic Structures
 Calcaneocuboid joint
 Slightly anterior to center of
knee joint
 Slightly posterior to center of
hip joint
 Sacral promontory
 Bodies of lumbar vertebrae
 Dens
 External auditory meatus
 Slightly posterior to apex of
coronal sutures
Surface Landmarks
 Slightly anterior to lateral
malleolus
 Slightly anterior to midline
through the knee
 Through the greater trochanter
 Midway through the back and
abdomen
 Midway between the front and
the back of the chest
 Through the lobe of the ear
From: Kendall HO, Kendall FP, Boynton DA. Posture and
Pain. Huntington, NY: Robert Keieger Publishing, 1970
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Alignment of Upper Extremity
Side View
Back and Front View
 Humerus – < 1/3 head of
humerus protrudes anterior to
acromion
 Proximal and distal humerus in
line vertically
 Scapula – inferior pole is flat
against thorax
 30 degrees anterior to frontal
plane
 Humerus – anticubital crease
faces anterior, olecranon faces
posterior
 Forearms – palms face body
 Scapula – vertebral border is
parallel to spine approximately
3 inches from spine
 Root at T3
 Vertebral border is held
against thorax
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Terminology
 Lordosis
 Kyphosis
 Anterior pelvic tilt
 Posterior pelvic tilt
 Genu valgum/varum
 Genu recurvatum
 Scapula
adduction/abduction
 Upward/downward
rotation of scapula
 Anterior/posterior tilt of
scapula
 Elevation/depression of
scapula
 Winging (medial rotation)/
lateral rotation of scapula
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Deviations In Posture
Posture stability is the foundation for movement.
Deviation from postural ideal alters the efficiency
of biomechanical system subjecting it to:
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Movement
Defined as the action of a physiologic system
that produces motion of the whole body or of its
component parts.
Evaluating active movement requires precise
observation and palpation skills and extensive
knowledge of kinesiologic principles.
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Criteria
A useful criteria for assessing
precise or balanced movement is
observing the path of
instantaneous center of rotation
(PICR) during active motion.
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PICR – Path of Instantaneous Center of Rotation
“The path of instantaneous center of rotation is the point around which
a rigid body rotates at a given instant of time.
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Force Couple
A major determinant of the PICR
during active motion is the
muscular force couple action on
the joint.
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Force Couple
Force couple is defined as two
forces of equal magnitude but
opposite direction with parallel
lines of application.
From: Nordin M, Frankel VH. Basic Biomechanics of the Musculoskeletal
System. Malvern, PA: Lea & Febiger, 1989.
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The force couple causes the body to
rotate around an axis perpendicular to the
plane of the forces.
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Muscle Dominance
Major determinant of PICR is the force couple on
the joint.
Deviation of PICR – Indication of faulty muscle
synergy in force couple.
Muscle dominance
Altered muscle synergy
Altered PICR
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Efficiency and longevity of biomechanical system
requires maintenance of ideal movement
patterns (kinesiologic ideal of PICR).
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Pathokinesiology – The study
of pathology as the cause of
abnormal movement.
Kinesiopathology – The study
of abnormal movement as the
cause of pathology.
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Causes of Impaired Posture
and Movement
Range of motion
Muscle length
Joint integrity/mobility
Muscle performance
Motor control
Neural integrity/mobility
Pain
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Range of Motion
Limits in joint ROM have significant postural
influence in relation to stability of the body.
Excessive joint ROM can allow postural
deviations in the corresponding directions
Limited ROM at a joint encourages faulty
alignment or movement at another segment.
Normal ROM does not ensure kinesiologic
standard of PICR; this is based on force couple
action on the joint.
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Muscle Length
Prolonged posture alterations can result in
muscle length changes.
Altered length can induce changes in supporting
tissues.
Contribute to perpetuating an established faulty
posture.
Alters length–tension properties affecting PICR.
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Joint Integrity/Mobility
Standard PICR must have available passive
osteo/arthrokinematics.
Impaired joint mobility often occurs in
conjunction with ROM, muscle length, muscle
performance, and motor control impairments.
Quality of motion may be affected without loss of
quantity of motion (i.e., anterior glide of head of
humerus with lateral rotation).
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Muscle Performance
Stretch weakness – Positional strength.
Length–tension properties of agonist dictates
participation in force couple.
Fatigability of muscle affects performance in
force couple.
Core strength (related to postural stability).
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PAIN
ALTERED POSTURE
OTHER ASSOCIATED
IMPAIRMENTS
ABNORMAL MOVEMENT
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Anatomic Impairments and
Anthropometric Measurements
Anatomic Impairments
Examples
Scoliosis
Kyphosis
Hip anteversion
Anthropometric
Characteristics
Examples
Broad shoulders w/
narrow pelvis
Long legs with tall
pelvis
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Psychological Impairments
Emotional factors can
affect posture and
movement.
Refer when
necessary.
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Life Span Considerations
 Child’s posture evolves until adulthood.
 Repeated evaluations may determine
habitual/acquired postural deviations.
 Scoliosis is a common and abnormal
development in children and should be
addressed immediately.
 Aging process includes minor neuromuscular
changes, but changes should be no more
exaggerated than in middle age.
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Environmental Factors
Workstations
Beds
Pillows
Car seats
School chairs
Desks
Footwear
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Examination and Evaluation
Postural Evaluation
Lends a window into
deviations in the various
points of reference
(plumb line) and
corresponding muscle
lengths.
Muscle Length Terms
 Tautness
 Short muscle
 Elongated muscle
 Tight
 Stiffness
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Movement
Single Joint Analysis
Palpation
Precise observation
Surface
electromyography
Multi-Segment
Breakdown
movement into
integral phases
Describe movement
pattern strategies
(e.g., primary knee
strategy with small
knee bends)
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Contributing Factor Information
Physiologic Impairments Contributing to Movement Impairment
ROM/Muscle Length
Joint Integrity/Mobility
Muscle Performance/Motor Control
By compiling results of contributing impairments, the clinician
can hypothesize about the quality of the PICR and the muscle
recruitment patterns during active movement.
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Essential Muscle Length Tests
Lower Quadrant
 Hamstring (medial vs.
lateral)
 Gastroc-soleus
 TFL – ITB
 Hip flexors (TFL, RF,
iliopsoas)
 Hip rotators (medial vs.
lateral rotators)
Upper Quadrant
 Teres major and
latissimus dorsi
 Rhomboid major, minor,
and levator scapula
 Pectoralis major
 Pectoralis minor
 Shoulder rotators (medial
vs. lateral rotators)
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Intervention
Physiologic impairments
Anatomic impairments
Psychological impairments
Predisposing factors
Previous interventions
Environmental influences
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Elements of Movement System
Base and biomechanical – Direct intervention for
posture and movement.
Modulator – Critical to movement system
intervention.
Cognitive or affective – May limit progress if
significant.
Support – Directly or indirectly, such as
breathing patterns or limited lung capacity.
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Activity and Dosage
Dosage
 Identify and prioritize
elements of the movement
system.
 Combine physiologic status
of components.
 Include posture, movement,
and mode parameters.
 Precise dosage depends on
impairment parameters.
Activities
 Stretch short muscles,
improve extensibility of stiff
tissues.
 Improve muscle
performance.
 Optimize body mechanics.
 Optimize balance and
coordination.
 Improve aerobic condition.
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Patient-Related Instructions
Education regarding
attention to postural
alignment in
frequently held or
prolonged positions.
IS KEY to:
1. Optimizing joint position
during rest & function.
2. Reducing tension placed
on elongated muscles.
3. Improving muscle
balance through
increasing tension placed
on shortened muscles.
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Adjunctive Interventions
Corsets
Bracing
Orthotics
Taping
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Summary
 Many physiologic impairments can contribute to and
perpetuate postural and movement impairments.
 Evaluation of posture and movement impairments
requires identifying deviations from acceptable standards
of contributing factors (structural, developmental, etc.).
 Therapeutic exercise intervention involves prioritizing
elements, determination of activities, techniques, stage
of motor control, prescription of dosage parameters.
 Successful treatment of impaired posture and movement
can directly affect kinesiopathologic factors.
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