1 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

2 Gait Analysis – Outline Source: – Jones, K. & Barker, K. (1996) Human Movement Explained, pp (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

3 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)

4 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.

5 The Gait Cycle:

6 Walking – The Stance Phase

7 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

8 Walking – The Swing Phase

9 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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11 GRF while walking

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13 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.

14 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 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

15 Muscular Activity while Walking

16 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)

17 Sample gait checklist

18 Analysis aids: Timing of foot contact

19 Analysis aids: Pressure on bottom of feet

20 Force Plates – Measurement of ground reaction forces

21 Optoelectric system - Vicon

22 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

23 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.