L9 - Gait Analysis

• What is Gait Analysis?

  • The analysis of body segments through space & time (kinematics) during locomotion (walking, running)
• What is Gait Analysis?

  • Walking often assessed to:
  • Monitor rehabilitation
  • Detect motor (dys)function
  • Evaluate equipment
  • How different shoes influence movement pattern
• What is Gait Analysis?

  • Running often assessed to:
  • Help avoid potential injury
  • Characteristics that could lead to injury
  • Improve comfort
  • Improve performance
  • Thru movement pattern
  • Evaluate equipment
• Phase Division of Gait:

  • Phases happen bw/ events
  • Look at angle in specific phase
  • One gait cycle - ground contact to next ground contact of same foot = a stride
  • A step = half a stride (right to left foot)
  • 80-95 cm is typical
  • Stance phase & Swing phase at same time with different legs
• Phase Division of Gait:

  • Stance phase = ground contact to toe-off
  • Stay on ground
  • Support = stance
  • Swing phase = toe-off to ground contact
  • In air
  • Double stance in walking replaced by flight phase in running
  • Double stance both feet in contact with ground (20% of gait?)
  • Not present during running
• Key Events in Stance Phase - Walking:

  • Ground strike = initial ground contact usually with heel
  • (heel strike/foot contact)
  • Foot flat = heel down, foot eversion/pronation
  • Mid-stance = support foot under pelvis, end of loading response, propulsion begins
  • Stop breaking, start propelling
  • When foot starts to push back
  • Heel-off = knee flexes usually with toe extension
  • Toe-off = foot leaves ground
• Sub-Phases of Swing Phase - Walking & Running:

  • Early-swing = hip & knee are flexing
  • Mid-swing = foot swings under pelvis, max knee flexion, hip still flexing
  • Late-swing = knee extending, hip stops flexing & laterally rotates
  • Coming close to ground
• Difference bw/ Walking & Running:

  • Balance more important in running, no double stance
  • esp in older individuals, strength is more important
  • Greater vertical displacement because of flight phase
  • CoM → moves up & down more
  • Muscles must generate & absorb more energy
  • Also have to propel self
  • Greater hip extension before ground strike, knee extended at toe-off
• Gait Analysis - Spatial Parameters:

  • Step length = distance bw/ consecutive ground strikes
  • Range of motion & limb length, should be symmetrical
  • One foot to another (eg right to left foot)
• Gait Analysis - Spatial Parameters:

  • Stride length = distance bw/ consecutive ground strikes of same leg
  • Same foot back in contact with ground
• Gait Analysis - Spatial Parameters:

  • Foot angle = orientation of foot (long axis) relative to line of progression
  • Influences amount of pronation & Windlass mechanism
  • Plays out different with different foot angles
  • If had came above could look at foot angle
  • Physio look at foot angle in line of progression, parallel to direction person moving/walking
• Gait Analysis - Spatial Parameters:

  • Base (step) width - ML distance bw/ ground-strikes (from heel) of each foot
  • Can increase with motor impairment
  • From the middle of the heel
  • Start increase step width when older to become more stable
• Gait Analysis - Knee flexion/extension:

  1. Max weight-bearing load
  2. Smooth extension to near full extension
  3. Heel lift, propulsion phase
  4. Toe-off at about 40 degreees, allows ground clearance
  5. Rapid extension preparing for heel-strike
• Gait Analysis - Knee flexion/extension:

  • Time 0 = foot contact; knee pretty much fully extended
  • Gradually increasing flexion
  • Knee starts flexing after toe-off
  • Flexion so when swing foot forward = for foot clearance so don't hit the ground & trip