Frequently Asked Questions about Clinical Gait Analysis

Introductory & Observational Gait Analysis   Practical difficulties    Identifying Segment Locations   Smoothing Electromyography  Normalisation  Anthropometry  Understanding Gait    File Formats  Gait Lab Admin 

Introductory & Observational Gait Analysis

  • observational gait analysis
  • 10 main pointers to look for
  • textbooks on gait analysis

    • Practical difficulties

  • getting the patient to walk 'normally'
  • hitting the force-platform
  • estimating foot contact and toe-off with kinematic data
  • effect of walkway carpeting
  • effect of shoes
  • the special challenges of analysing children
  • effect of walking aids
  • effect of arm-swing on gait
  • gait analysis with orthoses
  • physiological cost index (PCI)

    • Identifying segment locations

  • choice of motion analysis technique
  • 2D vs. 3D
  • The Direct Linear Transform
  • marker identification
  • marker-less tracking
  • marker sets
  • varus/valgus artifact & Cleveland marker set
  • marker-skin motion
  • coefficient of variation

    • Smoothing & differentiation

  • interpolation of missing markers
  • optimal filtering vs. fixed cutoff frequency
  • choice of cut-off frequency
  • accuracy of differentiation

    • EMG

  • quantification measures

    • Normalisation

  • normal data for adults and children
  • gender effects
  • Body mass & Stature or limb-length
  • Time
  • Velocity, cadence & stride length
  • Variability in joint moment & power patterns

    • Anthropometry

  • Joint centre estimation
  • Hip-joint centre estimation
  • Knee anthropometry
  • measurement vs. regression estimation
  • Accuracy requirements
  • Prostheses

    • Understanding gait

  • kinematics
  • the Determinants of Gait
  • forces & moments
  • friction & resolving forces
  • origin of ground reaction forces
  • center of pressure
  • inverse-dynamics
  • passive vs. active dynamics
  • interpretation of joint moments and powers
  • segment powers
  • balance
  • control of motion & locomotion
  • how many steps do we take in a year?
  • femoral anteversion & tibial torsion

    • File Formats

  • the C3D file format
  • the GCD and DST format

    • And frequent administrative questions...

  • how much to charge for a gait analysis?
  • how to start a gait-lab?


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    Maintained by Dr Chris Kirtley
    Last modified on  20-Oct-99