Gait Analysis – Objectives

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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)

• 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 walkingVGRF is much greater thanHoriz forces

Peak walking VGRF are ~1.2 BW and increase with speed

Peak running VGRF is 2-5 times BW and increases withRunning speed

First peak when running occursDuring first 50 ms of footContact and is called passivePeak.

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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• 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

• 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.