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– 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)

• 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:

• 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 part of stance phase

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Clinical Methods of Studying Gait

• Observational techniques (use checklist, and videotape when possible)(Slide 17)

• Quantitative analysis– 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

• 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