Lec 2: Gait Kinematics

Question 1

Gait Cycle Stride Subphases: Stance

Answer 1

1. Initial Contact (Weight Acceptance, Double Support)
2. Loading Response (Weight Acceptance, Double Support)
3. Mid stance (Single Limb Support)
4. Terminal Stance (Single Limb Support)
5. Pre Swing (Swing Limb Advancement, Double Support)

Question 2

Gait Cycle Stride Subphases: Swing

Answer 2

6. Initial Swing (Swing Limb Advancement)
7. Mid Swing (Swing Limb Advancement)
8. Terminal Swing (Swing Limb Advancement)

Question 3

Term for torque in gait

Answer 3

Joint Movement
-amount force that is required to stabilize or create movement in a joint axis
-Limb in a contact or loaded position (stance) stabilizes or absorbs force or is the freely moving joint (swing)

Question 4

Initial Contact (IC) (0%)

Answer 4

Critical Event: Heel contact w/ ground
Ankle: 0 °, correct position for loading, heel rocker initiated
Knee: 0-5 °, contact creates moment/torque
Hip: 20 ° flexion, high intensity torque

Question 5

Loading Response (LR) (2-12%)

Answer 5

Critical Event: Hip stability, controlled knee stability for shock absorption, ankle in PF
Ankle: 5 ° PF (rapid change), heel rocker initiated
Knee: 15 ° for shock absorption
Hip: 20 ° flexion, high torque (2nd highest torque demand for stability)

Question 6

Midstance (12-50%)

Answer 6

Critical Event: controlled tibial advancement, limb in single limb support
Ankle: 5 °PF, talocrural joint moves over fixed foot, ankle 2nd rock is obtained
Knee: °5 flexion (moving into extension), tibia advancement begins after mid-stance
Hip: Hip extends to neutral, pelvis and hip are stabilized

Question 7

Midstance Biomechanics

Answer 7

Fixed foot (ankle rocker) with full foot contact for tibial advancement. Talocrural joint serves as the fulcrum.

Question 8

Four Rockers in Stance Phase

Answer 8

1. Heel Rocker: contact of calcaneus with ground
2. Ankle (Talocrural) Rocker: fixed foot with full foot contact
3. Forefoot Rocker: forefoot contact, calcaneus moves out of contact
4. Toe Rocker: great toe serves as base of contact, from forefoot contact into I metatarsal contact

Question 9

Terminal Stance

Answer 9

Critical Event: force generation for propulsion forward, controlled DR w/ heel rise, loaded limb in single limb stance
Ankle: moves to 10 ° DF, I metatarsal into 30 ° ext, 3rd ankle/forefoot rocker emerges
Knee: 0-5 °, calf muscle increases motor function to prevent loaded limb collapse
Hip: 20 ° extension

Question 10

“Trailing Limb”

Answer 10

-Terminal Stance
-allows for greater step length, key importance for clinical interventions

Question 11

Pre Swing (50-62%)

Answer 11

Critical Event: passive knee flexion to 40 °, ankle PF
Ankle: 15 ° PF, metatarsals move to 60 ° extension, toe rocker (forefoot contact to I metatarsal contact)
Knee: 40 ° flexion, critical for knee to flex to clear foot to prepare for limb advancement
Hip: 10 ° extension, limb advancement beginning

Question 12

Initial to Mid Swing (62-87%)

Answer 12

Critical event: thigh begins to advance, foot clears ground

Question 13

Initial Swing

Answer 13

Critical event: hip flexion to 15 °, knee flexion to 60 °
Ankle: 5 ° PF (moving toward neutral)
Knee: 60 °
Hip: 15 °

Question 14

Midswing

Answer 14

Critical Event: hip flexion to 25 °, ankle DF to 0 °
Ankle: moves to neutral 0 (clears ground by 1cm)
Knee: 25 ° (moving rapidly into extension)
Hip: 25 °

Question 15

Terminal Swing (87-100%)

Answer 15

Critical Event: knee extension to neutral/or 5 ° of flexion, limb reaches out to achieve step length, limb positioned for heel contact
Ankle: DF to neutral
Knee: knee extends to neutral or 5 ° flexion, active quads to achieve step length
Hip: 20 ° flexion

Question 16

Sagittal Plane Pelvic Tilt

Answer 16

-anatomically pelvis sits at 10 ° APT
-w/ ambulation pelvis tilts additional 4 ° anteriorly during terminal stance
-in early single leg stance a posterior tilt occurs

Question 17

Frontal Plane Pelvic Tilt

Answer 17

-during weight acceptance contralateral side of pelvis drops 4 ° (downward tilt)

Question 18

Frontal Plane Kinematics: Hip

Answer 18

-stabilization of hip and pelvis in frontal plane from IC through Pre-Swing (stance phase limb)
-from IC to end of LR: 0-10° Add.

Question 19

Frontal Plane Kinematics: Knee

Answer 19

-stance phase: knee must remain in alignment w/ hip and ankle (no overt varus or valgus)

Question 20

Frontal Plane Kinematics- Stance Phase: Subtalar (Talocalcaneal) Joint

Answer 20

-Stance phase: subtalar joint responsible for supination and pronation, closed chain
-Loading response (CC or stance phase): calcaneus everts 5° & subtalar moves into pronation

Question 21

Unlocking of midtarsal joints

Answer 21

-via calcaneus eversion and subtalar pronation
-assists in ankle shock absorption and reduced stress of loading impact
-tibia moves slightly into IR

Question 22

Frontal Plane Kinematics- Terminal Stance: Subtalar (Talocalcaneal) Joint

Answer 22

-during late terminal stance
-subtalar calcaneal eversion reduces from 5° to 2°, moving into supination

Question 23

Locking of midtarsal joints

Answer 23

-increased stability to midtarsal joints
-creates rigid forefoot level in terminal stance: moving toward supination
-help to promote Forefoot rocker (3rd rocker)

Question 24

Transverse Plane: Pelvis Rotation

Answer 24

Terminal Stance: pelvis retraction 5°
Mid Swing: Pelvis Neutral
Terminal Swing: pelvis forward rotation 5°
Pelvic rotation allows for longer step/stride length

Question 25

Transverse Plane: Trunk Rotation

Answer 25

-Thoracic rotation results in shoulder forward rotation and creates arm swing
-Thoracic forward rotation coincides with contralateral pelvis rotation