Lecture 2: Gait Kinematics Flashcards
What are two methods to analyze gait?
Kinematic and breaking gait into 8 subphases of swing and stance
What are the different subphases in stance?
initial contact, loading response, mid stance, terminal stance, pre-swing
What are the different subphases in swing?
initial swing, mid swing, terminal swing
What is the task of initial contact and loading response?
weight acceptance
What is the task of midstance, terminal stance?
single limb support
What is the task of pre-swing, initial swing, mid swing, and terminal swing?
swing limb advancement
Which subphases of stance are in double support? Single support?
Double support: IC, LR, Pre-swing
Single support: mid stance, terminal stance
What is torque?
-angular force or joint moment
-measure of force that can cause an object to rotate about an axis
What is the gait term for torque? Definition
joint moment - amount of force required to stabilize or create movement in a joint axis
First subphase? Critical event?
-initial contact
-heel contact w/ ground
Ankle, knee and hip ROM for IC in sagittal plane
Ankle: ROM at 0 degrees (heel rocker initiated)
Knee: 0-5 degrees (contact creates a moment/torque)
Hip: 20 degrees flexion (high intensity torque)
Second subphase? Critical event?
-loading response
-hip stability, knee stability (shock absorption), ankle PF
Ankle, knee and hip ROM for loading response in sagittal plane
Ankle: 5 degrees PF (heel rocker initiated)
Knee: 15 degrees (shock absorption)
Hip: 20 degrees flexion (high torque: 2nd highest torque demand for stability)
3rd subphase? Critical event?
-midstance
-controlled tibial advancement
Ankle, knee, and hip ROM for midstance in sagittal plane
Ankle: moves to 5 degrees PF, foot in closed chain position, talocrural joint moves over fixed foot , ankle 2nd rocker is obtained
Knee: moves into extension (still maintains 5 degrees flexion)
Hip: extends to neutral, pelvis and hip are stabilized
Briefly describe midstance biomechanics
fixed foot (ankle rocker) with tibial advancement, talocrural joint is fulcrum
What are the 4 types of midstance biomechanics
heel rocker, ankle rocker, forefoot rocker, toe rocker
What is heel rocker?
contact of calcaneus with ground
What is ankle rocker?
fixed foot with full foot contact
What is forefoot rocker?
calcaneus moves out of contact, forefoot contact
What is toe rocker?
great toe serves as the base of contact
4th subphase? critical event?
-terminal stance
-controlled DF with heel raise (force generation for propulsion forward)
Ankle, knee, and hip ROM for terminal stance in sagittal plane
Ankle: moves to 10 degrees DF, 1st metatarsal moves to 30 degrees of flexion, 3rd ankle rocker or forefoot rocker emerges
Knee: 0-5 degrees, calf increases motor function and prevents collapse of loaded limb
Hip: extends to 20 degrees
What does the trailing limb allow?
greater step length
key importance for clinical interventions
5th subphase? Critical event?
-pre-swing
-passive knee flexion to 40 degrees, ankle PF
Ankle, knee, and hip ROM for pre-swing
Ankle: 15 degrees PF, MT 60 degrees flexion, fore foot contact to first MT contact (toe rocker)
Knee: 40 degrees flexion, critical for knee to clear foot in preparate
Hip: 10 degrees extension, limb advancement begins
Initial swing critical event
hip flex 15 degrees, knee flex to 60 degrees
Ankle, knee, and hip ROM for initial swing in sagittal plane
Ankle: moves to 5 degrees of PF (moves toward neutral)
Knee: moves to 60 degrees
Hip: flexion to 15 degrees
Mid swing critical event
hip flex to 25, DF to 0
Ankle, knee, and hip ROM for mid swing in sagittal plane
Ankle: moves to neutral 0 degrees (clears ground by 1 cm)
Knee: moves rapidly to ext, moves to 25 degrees
Hip: flexion to 25 degrees
Terminal swing critical event
knee ext to neutral (or 5 degrees of flex)
Ankle, knee and hip ROM for terminal swing in sagittal plane
Ankle: DF to neutral
Knee: extends to neutral (or 5 degrees flex), active quads to achieve step length
Hip: flex to 20 degrees
How much does the pelvis anteriorly tilt anatomically?
10 degrees
How much does the pelvis tilt with ambulation? Which phase?
-additional 4 degrees anteriorly
-terminal stance
When does pelvic tilt in front plane? How much?
-during weight acceptance
-contralateral side of pelvis drops 4 degrees
What are the frontal plane kinematics in the hip?
Stance phase limb on R
-stabilizes the hip and pelvis from initial contact through pre swing
How much movement occurs in hip from initial contact to end of loading response in frontal plane?
0 to 10 degrees ADD
Knee kinematics in frontal plane on stance phase
Knee must stay in alignment w/ hip and ankle (no varus or valgus)
What is the subtalar joint responsible for?
Supination and pronation
What happens to the subtalar joint during loading response in the frontal plane? What does this unlock and assist with?
Calcaneus everts 5 degrees and the subtalar joint moves into pronation
Unlocks midtarsal joints
Assists in ankle shock absorption and reduces stress of loading impact
What happens to the tibia when calcaneus everts
IR
What happens to the subtalar joint during late terminal stance? What does this do to midtarsal joints? What does it promote?
Subtalar calcaneus version reduces from 5 to 2 degrees
Increases their stability - creates rigid forefoot level in terminal stance moving toward supination
Promotes 3rd rocker (forefoot rocker)
Describe the pelvis rotation in transverse plane during terminal stance, mid swing and terminal swing
TStance - pelvis retraction 5 degrees
Mid swing - pelvis neutral
TSwing - pelvis forward rotation 5 degrees
Describe trunk rotation in transverse plane
Thoracic rotation results in shoulder forward rotation and creates arm swing; rotation coincides w/ contralateral pelvis rotation