Gait Kinematics

Question 1

What subphases make up the stance phase?

Answer 1

1. initial contact
2. loading response
3. mid stance
4. terminal stance
5. pre-swing

Question 2

What subphases make up the swing phase?

Answer 2

6. initial swing
7. mid swing
8. terminal swing

Question 3

In which subphases does weight acceptance occur?

Answer 3

initial contact and loading response

Question 4

In which subphases does single limb support occur?

Answer 4

mid stance and terminal swing

Question 5

In which subphases does limb advancement occur?

Answer 5

Pre swing, initial swing, mid swing, and terminal swing

Question 6

What is observed during the subphases of the gait cycle?

Answer 6

Timing, ROM and joint excursions
Observation of the trunk, pelvis, knee, and ankle occur during each subphase to see if it is normal or if there are any asymmetries

Question 7

What is torque and how is it used to measure gait?

Answer 7

torque is an angular force or joint movement that can cause an object to rotate about an axis

Question 8

What is the term for torque in gait?

Answer 8

Torque would be referred to as joint movement.

Question 9

What is joint movement?

Answer 9

it is the amount of force that is required to stabilize or create movement in a joint axis

Question 10

What is an essential aspect?

Answer 10

Is the limb in a contact or loaded position (stance) which is to stabilize or absorb force or is the joint freely moving (swing)

Question 11

Initial Contact

Answer 11

Critical event: heel contact with neutral dorsiflexion
Ankle: ROM 0 degrees, heel rocker initiated
Knee: knee 0-5 degrees, contact creates a moment/torque
Hip: hip flexion 20 degrees, high intensity torque

Question 12

Loading Response

Answer 12

Critical event: hip stability, controlled knee stability (shock absorption), & ankle plantar flexion
Ankle:5 degrees of plantar flexion (rapid change), heel rocker initiated
Knee: 5 degrees of flexion (shock absorption
Hip: 20 degrees of flexion, 2nd highest torque/demand for stability

Question 13

Midstance (LE is in single limb support)

Answer 13

Critical Event: controlled tibial advancement
Ankle: 5 degrees of plantarflexion, foot is in closed chain, talocrural joint moves over fixed foot, 2nd rocker is obtained
Knee: moves into extention, 5 degrees of flexion maintained, tibia advancement begins after midstance
Hip: extends to neutral, pelvis and hip are stabilized

Question 14

When does tibia advancement begin?

Answer 14

after mistance

Question 15

What are the biomechanics of midstance?

Answer 15

The foot is in a fixed position (ankle rocker) with tibia advancement.

Question 16

What occurs throughout tibia advancement?

Answer 16

1. Heel rocker: contact of calcaneus with ground
2. Ankle rocker: fixed foot with full foot contact
3. Forefoot rocker: calcaneus moves out of contact, forefoot contact
4. Toe rocker: great toe serves as the base of contact

Question 17

Terminal Stance ( loaded limb is in single limb stance)

Answer 17

Critical event: controlled dorsiflexion with heel rise, force generation for propulsion forward
Ankle: moves to 10 degrees dorsiflexion, 1st metatarsal moves to 30 degrees of flexion, 3rd ankle rocker or forefoot rocker emerges
Knee: Calf muscle increases motor function to prevent collapse of loaded limb, 0-5 degrees of flexion
Hip extends to 20 degrees

Question 18

What is trailing limb and in what stance does it occur?

Answer 18

Trailing limb allows for greater step length and it occurs in terminal stance

Question 19

Pre-Swing (preparing the limb for advancement (50-62%)

Answer 19

Critical Event: passive knee flexion to 40 degree, ankle plantarflex
Ankle: move to 15 degrees of plantarflexion
Knee: Knee moves in 40 degrees of knee flexion critical for knee to flex to clear foot in preparate
Hip: hip moves to 10 extension, limb advancement is beginning

Question 20

Sagittal Plan Kinematics

Answer 20

1. Initial contact: note the heel contact and the neutral angle
2. Loading response: foot flat contact with slight knee flexion, knee begins stability phase
3. Midstance: note the tibia advances over the fixed foot structure
4. Terminal stance: highest moment in gait cycle

Question 21

Initial Swing

Answer 21

Critical event: hip flex 15 degrees, knee flex to 60 degrees
ankle: moves to 5 degrees of plantar flexion (moving towards neutral)
Knee: moves to 60 degrees
Hip: flexion to 15 degrees

Question 22

Mid-swing

Answer 22

Critical Event: hip flex 25 degrees, ankle dorsiflex to 0
Ankle: moves to neutral 0 degrees (clears the ground by one centimeter)
knee: moves rapidly to extension, moves to 25 degrees
Hip: flexion moves to 25 degrees

Question 23

Terminal Swing (limb reaches out to achieve step length/positioned for heel contact)

Answer 23

Critical event: knee extension to neutral (or 5 degrees of flexion)
Ankle: dorsiflexion to neutral
Knee: knee extends to neutral (or 5 degrees) active quads to achieve step length
Hip: flex to 20 degrees

Question 24

Pelvic tilt (anatomically v w/ ambulation)

Answer 24

-Anatomically the pelvis sits at 10 degrees of anterior pelvic tilt
- w/ ambulation, pelvis tilts an additional 4 degrees anteriorly (unseen by vision) during terminal stance)

Question 25

In which stance does a posterior tilt occur?

Answer 25

in early single leg stance

Question 26

What occurs during weight acceptance?

Answer 26

The contralateral side of the pelvis drops 4 degrees (downward tilt in the frontal plane)

Question 27

Frontal plane kinematics of the hips

Answer 27

-Stabilize the hip and pelvis in the frontal plane from initial contact through pre swing (avoids excessive hip drop) -Small frontal plane movement of the hip from initial contact to the end of the loading response 0-10 degrees adduction

Question 28

Frontal plane kinematics of the knee

Answer 28

On the stance phase the knee must remain in alignment with the hip and ankle (no overt varus and valgus)

Question 29

What is the subtalar joint responsible for in the frontal plane?

Answer 29

Subtalar joint is responsible for supination and pronation.

Question 30

Frontal plane kinematics of the subtalar joint during loading response

Answer 30

-Loading response: closed chain or stance phase kinematics, the subtalar joint moves into pronation - this action unlocks the midtarsal joints (absorbs shock and reduces stress of loading impact) - Moves the tibia slightly into IR

Question 31

Frontal plane kinematics of the subtalar joint during terminal stance

Answer 31

-During late terminal stance: the subtalar calcaneal eversion reduces from 5 to 2 degrees - Action increases the midtarsal joints, creates a rigid forefoot level, moves towards supination - This action helps promote third rocker

Question 32

Transverse plane pelvic rotation

Answer 32

- Terminal stance phase: pelvis retraction 5 degrees - Mid Swing: pelvis neutral - Terminal swing: pelvis forward rotation 5 degrees - Pelvis rotation allows for longer step/stride length

Question 33

Transverse plane trunk rotation

Answer 33

-Thoracic rotation results in shoulder forward rotation and creates arm swing -thoracic