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
– The joint range of motion and muscle activity during
walking
– The differences between movement patterns, muscle
activity, range of motion, and forces of walking and
running
– The clinical methods of studying gait
– Gait changes with normal ageing
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Gait Analysis – Overview
• 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
Range of motion at the joints in walking
Running analysis
– Muscle activity
• Clinical methods of gait analysis
• Gait changes with age and disease
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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 (Human Gait)
• Human gait provides a method of locomotion. As a
species, we are “bipedal” meaning we move on two
extremities.
• Walking, while usually taken for granted by most of us,
is an extremely complex movement.
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The gait cycle
• Distance and temporal factors in gait (Fig 15.1)
– Foot angle, step length, stride length, step width
• The gait cycle (Fig 15.2)
– Stance phase (60 %)
– double support phase (20%)
– swing phase (40%)
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Walking Analysis … the process
• A gait cycle consists of “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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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 (Fig
15.3)
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Running Analysis…...
• Running is similar to walking BUT, it differs
significantly in a number of ways, for example:
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No period of “double support”
Float periods (both feet airborne)
Requires greater balance
Requires greater strength
Requires greater ROM at hip, knee, and ankle joints
Involves greater excursion of center of mass
Involves greater ground reaction forces
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Running – A Gait Cycle
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Muscle Activity in Running...
• Glut. Max. & med. -- active at the beginning of the stance
phase (concentrically) and again at the end of the swing
phase (eccentrically).
• Iliopsoas -- active during a portion of the swing phase
(concentrically).
• Quadriceps -- 1st 10% of the stance phase (eccentrically)
and last 20% of the swing phase (concentrically).
• Hamstrings -- initial portion of the swing phase
(concentric) and at the end of the swing phase
(eccentric).
• Plantar flexors (gastrocnemius & soleus) – Mid and latter
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part of stance phase
Clinical Methods of Studying Gait
• Observational techniques (use checklist, and videotape
when possible)(Slide 17)
• Quantitative analysis
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time-distance measurements (stop watch, footswitches) (Slide 18)
Kinetic techniques (Slide 19 & 20)
Kinematic analysis
Videotaping, semi-automated imaging (Slide 21)
Combined kinematic and kinetic (Slides 20 & 21)
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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
Increased double support time
Greater variation in stride width
Wider base of support
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