Transcript Part IV Lower Extremities

Gait Analysis – Objectives
• To learn and understand:
– The general descriptive and temporal elements of the normal
walking movement
– The important features and components of both the swing and
stance phases of the gait cycle
– Ground reaction forces (GRF) while walking
– Normal ROM of pelvic girdle, hip, knee, ankle while walking
– Muscle activity while walking
– The clinical methods of studying gait
– Gait changes with normal ageing
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Gait Analysis – Outline
• Source:
– Jones, K. & Barker, K. (1996) Human Movement Explained, pp
297-324 (on reserve)
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Clinical uses of gait analysis
The gait cycle
Ground reaction forces during walking
Joint movements while walking
Muscle activity while walking
Clinical methods of gait analysis
Gait changes with normal aging
Study questions
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Clinical uses of gait analysis
• Assesses the degree and extent of departure
from the norm
• Documents changes due to therapeutic
interventions
• Evaluates results of rehab (improvement)
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Walking Analysis … the process
• A gait cycle consists of two steps, or one stride
“the activities that occur from the point of initial
contact of one lower extremity to the point at
which the same extremity contacts the ground
again”
• During one gait cycle, each extremity passes
through two phases, a single stance phase and a
single swing phase.
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The Gait Cycle:
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Walking – The Stance Phase
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Components of the Stance Phase
• Stance phase comprises 60% of the gait cycle
• Heel strike – moment when the heel first strikes
the ground
• Foot flat – from heel strike to when the full foot is
in contact with the ground
• Midstance – body weight is directly over the
stance leg
• Heel off – moment the heel of the stance leg
leaves the ground
• Toe off – when only the toe of the stance leg is in
contact with the ground
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Walking – The Swing Phase
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Components of the Swing Phase
• Swing phase comprises 40% of the gait cycle
• Acceleration – the toe of the stance leg leaves the
ground and begins to swing forward
• Midswing – the swinging leg is directly beneath
the body
• Deceleration – the swinging leg continues forward
towards knee extension but is slowing down as it
travels, stopping just prior to full knee extension
and heel contact with the ground
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GRF while walking
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VGRF While walking
VGRF is much greater than
Horiz forces
Peak walking VGRF are ~1.2
BW and increase with speed
Peak running VGRF is 2-5
times BW and increases with
Running speed
First peak when running occurs
During first 50 ms of foot
Contact and is called passive
Peak.
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Range of motion at the joints
• Trunk - As left leg moves forward, pelvis rotates clockwise
as viewed from above 7 deg
• Hip Joint (30 deg flex at HS strike, 180 deg at TO)
– Stance - extension, adduction, internal rotation
– Swing - flexion/extension, abduction, ext rotation
• Knee joint - 180 deg at HS, 160 deg at mid-stance
• Ankle joint - Neutral at HS, hinges down during support,
and plantar flexes at TO . ROM 30 deg
• COM displacement +5 cm bilaterally and vertically
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Muscular Activity while Walking
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Clinical Methods of Studying Gait
• Observational techniques (use checklist, and videotape
when possible)(usually conducted by therapists)(Slide 17)
• Quantitative analysis – when more precise info is needed
(usually provided by gait analysis laboratories)
– time-distance measurements (stop watch, footswitches) (Slide 18)
– Kinetic techniques (Slide 19 & 20)
– Kinematic analysis using videotaping, semi-automated imaging
(Slide 19)
– Combined kinematic and kinetic (19)
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Sample gait
checklist
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Analysis aids:
Timing of foot
contact
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Analysis aids:
Pressure on bottom
of feet
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Force Plates –
Measurement of ground
reaction forces
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Optoelectric system - Vicon
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Gait changes with normal ageing
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Lower walking speeds
Shorter step and stride lengths
Reduced plantar flexor force production
Reduced hip extension
Reduced pelvic girdle and hip rotation
Increased double support time
Greater variation in stride width
Wider base of support
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Study questions
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Name three general clinical uses of gait analysis
What is a gait cycle?
What are the 5 components of the stance phase?
What are the 3 components of the swing phase?
In normal walking, the stance phase comprises what
percentage of the gait cycle?
• In normal walking, what is the peak GRF relative to body
weight?
• List 8 changes in gait due to aging.
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