Gait Flashcards
Human locomotion compromises compared to primate?
- Spine
- curved (kyphosis, lordosis)
- weak points - Pelvis
- squashed down to bear weight - Foot
- made for walking
- combines hallux into toes
Key requirements for locomotion?
- Control
- stability
- clearance
- prepositioning - Periodicity
- control step length
- cadence (rate of steps) - Propulsion (force)
- ground reaction forces
- up and forward, more force going forward
Stride vs step length?
- Stride: 2 steps
- Step: 1 step (38 cm)
- step width: heel to heel
- cadence: steps/time
- velocity: cadence plus stride length (3 mph)
Center of gravity?
5cm anterior to 2nd sacral vertebrae
-below umbilicus
Traditional nomenclature of gait?
- Heel strike
- Foot flat
- Midstance
- Heel off
- Toe off
- Acceleration
- Midswing
- Deceleration
RLA nomenclature of gait?
- Initial contact
- Loading response
- Midstance
- Terminal stance
- Preswing
- Initial swing
- Midswing
- Terminal swing
- Heel strike/Initial contact?
- Lower forefoot: ankle dorsiflexors (eccentric)
- Decelerate: Hip extensors (concentric)
- Maintain arch: intrinsic muscles and long tendons of foot
- Flat foot/Loading response?
- Accept weight: Knee extensors (eccentric)
- Decelerate: Ankle plantar flexors (eccentric)
- Stabilize pelvis: Hip Abductors (eccentric)
- Maintain arch: intrinsic muscles and long tendons of foot
- Midstance?
- Stabilize knee: Knee extensors (eccentric)
- Control Dorsiflexion: Ankle Plantarflexors (eccentric)
- Stabilize pelvis: Hip abductors (eccentric)
- Maintain arch: intrinsic muscles and long tendons of foot
- start to generate force
- Heel off/terminal stance?
- Accelerate mass: ankle plantar flexors (concentric)
- Stabilize pelvis: Hip abductors (eccentric)
- Maintain arch: intrinsic muscles and long tendons of foot
- Toe off/preswing?
- Accelerate mass: long flexor of digits and intrinsic muscles of foot (concentric)
- Decelerate thigh: Hip flexors (eccentric)
- Maintain arch: long tendons of foot
- Acceleration/initial swing?
- Accelerate thigh: Hip flexors (concentric)
2. Clear foot: ankle dorsiflexors (concentric)
- Midswing?
- Clear foot: ankle dorsiflexors and knee flexors (concentric)
- Deceleration/terminal swing?
- Decelerate thigh: Hip extensors (eccentric)
- Decelerate leg: knee flexors (eccentric)
- Position foot: ankle dorsiflexors (concentric)
- Extend knee: knee extensors (concentric)
Two theories of gait?
- Six determinants of Gait
2. Inverted pendulum
Six determinants of gait theory?
- Pelvic rotation
- Pelvic tilt
- Stance knee flexion
- Foot mechanisms
- Knee mechanisms
- Lateral displacement of pelvis
- most efficient form of locomotion is with minimized movement of center of mass
Pelvic rotation?
- rotation of the pelvis to the right and left of body axis
- rotates 4-6 degrees in either direction
- lengthens both limbs
- keeps center of mass from dropping
Pelvic tilt?
- rotation of pelvis around either a horizontal axis
- pelvis rotates 4-5 degrees on swing side
- lowers center of mass at mid stance
Stance knee flexion?
- knee flexion at mid stance (15 degrees)
- lowers center of mass
- combines with pelvic tilt and rotation to reduce vertical displacement of center of mass
Foot and ankle mechanism?
- at initial contact:
- ankle plantar flexion - at preswing:
- ankle elevated (dorsiflexion)
- smooths passage of center of mass during stance
- COM higher at points where legs farther apart
Knee mechanisms?
- associated with foot and ankle:
- an ankle approaches surface, knee extends - at initial contact:
- knee extended - during mid stance:
- knee flexes - at preswing:
- knee extends
-smooths passage of COM during stance
Lateral pelvic displacement?
COM shifted toward stance limb
- keeps COM over stance foot
- deviation of COM from base of support requires energy to correct
Inverted pendulum theory?
- inherently unstable, must be actively balanced
- work expected to elevate center of mass recaptured on decline
- transition to opposite leg requires movement in coronal plane
- negative vs positive work
Difference between walking and running?
- flight: double support time lost
- time where neither foot is on ground
Bare feet vs shod while running?
- provide support and shock absorption with heel strike
2. minimal difference if running by forefoot strike