Gait Flashcards
Displacement of COG vertically during gait
2 cm
Highest during mid stance
Lowest during loading response
Displacement of COG laterally during gait
4 cm total (2 each way)
Greatest during single limb stance
Where is COG?
2 cm anterior to S2
BWV during standing (passive/ static stability)
Posterior to hip
Anterior to knee
Anterior to ankle
“Passenger Unit” of gait
HAT Head Arms Trunk 70% of body weight **Dominates body vector alignment
“Locomotor Unit” of gait
Two lower limbs and pelvis
11 articulations
Toe out
Angle formed by intersection of foot’s lien of progression and the line from the center of the heel through the 2nd metatarsal
Normal = 7 degrees
Females > Males
New walkers
Step Length
Linear distance between point of initial contact of one foot to the same point of initial contact on the opposite foot
Named for which foot is put forward
Stride Length
Linear distance between point of initial contact of the ipsilateral heel
Normal = 1-5 ft
Stride Duration
Amount of time required to accomplish one stride (2 steps)
Average = 1-2 seconds
Cadence
Number of steps per minute
Normal = 90-120 steps/minute
Velocity
Distance per minute
Normal = 80 m/min = 3mph
Initial Contact
Exact moment when foot just touches floor
Objective: Position limb for stance
Loading Response
Begins with initial contact and continues until the other foot is lifted for swing Objectives: 1. Shock absorption 2. Weight transfer to forward limb 3. Preservation of progression
Mid Stance
Begins just after opposite foot is lifted and continues until body weight is aligned over stance forefoot
Objectives:
1. Progression over stationary foot
2. Limb/ trunk stability
Terminal Stance
Begins with heel rise of the stance limb, continues until opposite foot strikes ground
Objective: Progression beyond supporting foot
Pre Swing
*Final phase of stance
Begins with initial contact of opposite limb, ends with ipsilateral toe off
Objective: Position of limb for swing, weight is shifted to opposite leg
Initial Swing
Begins with lift off of foot and ends when swinging foot is opposite stance foot
Objectives:
1. Clear foot of floor
2. Advance limb from trailing position
Mid Swing
Begins as swinging limb is opposite stance limb, ends when swinging limb is forward and tibia is vertical
Objectives:
1. Limb advancement
2. Foot clearance from ground
Terminal Swing
Begins with tibia vertical, ends when foot strikes floor (IC)
Objectives:
1. Complete limb advancement
2. Prepare limb for stance
2 mechanisms of energy conservation in gait
- Minimizing excursion of COG (pelvic motion and combining knee and ankle motion)
- Selective muscle control (try to maximize passive momentum vs. active muscle action)
Objective of IC
Position limb for stance
Objective of loading response
Shock absorption
Weight transfer to forward limb
Preservation of progression
Objective of midstance
Progression over stationary foot
Limb/ trunk stability
Objective of terminal stance
Progression of body beyond stationary foot
Objective of pre-swing
Position limb for swing (weight shift to other limb)
Objective of Initial Swing
Clear foot of floor
Advance limb from trailing position
Objective of Mid-Swing
Limb advancement
Foot clearance from floor
Objective of Terminal Swing
Complete limb advancement
Prepare limb for stance
Ankle Rocker Phase
Mid-Stance
Forefoot Rocker Phase
Late Terminal stance, when axis of motion has reached MT heads
Heel Rocker Phase
Loading Response
5 Prerequisites of normal gait
- Stability in stance
- Adequate clearance in swing
- Pre-position for initial contact
- Adequate step length
- Energy conservation
Most critical phase for gluts
Loading Response
Compensation for weak gluts: shorter steps (less hip flexion to counteract)
Maximum anterior pelvic tilt
Initial Contact
Maximum posterior pelvic tilt
Preswing/ toe off
When does pelvic tilt (anterior to posterior) reverse?
During midstance and midswing
Sub-Talar joint motion during LR - Mid Stance
Calcaneus everts
Mid-tarsal joint unlocks –> pronation (shock absorption)
Posterior tib fires eccentrically to lower talus
Tibia internally rotates
Sub-Talar joint motion during Terminal Stance
Calcaneal inversion
Mid-tarsal joint locks –> supination (stability for propulsion)
Posterior tib fires concentrically (PF)
Tibia externally rotates
