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 clinical methods of studying gait Gait changes with normal ageing

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 Clinical methods of gait analysis Gait changes with age and disease

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)

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.

The Gait Cycle:

Walking – The Stance Phase

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

Walking – The Swing Phase

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

GRF while walking

Clinical Methods of Studying Gait Observational techniques (use checklist, and videotape when possible)(usually conducted by therapists)(Slide 14) Quantitative analysis – when more precise info is needed (usually provided by gait analysis laboratories) time-distance measurements (stop watch, footswitches) (Slide 15) Kinetic techniques (Slide 16 & 17) Kinematic analysis using videotaping, semi-automated imaging (Slide 18) Combined kinematic and kinetic (18)

Sample gait checklist

Analysis aids: Timing of foot contact

Analysis aids: Pressure on bottom of feet

Force Plates – Measurement of ground reaction forces

Optoelectric system - Vicon

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

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 4 components of the swing phase? In normal walking, the stance phase comprises what percentage of the gait cycle? List 8 gait changes in gait due to aging.

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

Running – A Gait Cycle

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