Week 8: gait

Question 1

What is gait

Answer 1

Walking

Question 2

Cyclical

Answer 2

repetitious sequence of limb motions to move body forward

Question 3

Two stages of gait

Answer 3

1. Stance: foot in contact with ground
2. Swing: no ground contact

Question 4

Percentage of gait cycle

Answer 4

Stance 60%

Question 5

Gait

Answer 5

The manner or style of walking

Question 6

Gait cycle

Answer 6

A fundamental unit to describe the gait during ambulation. This occurs from the time when the heel of one foot strikes the ground to the time at which the heel of the same foot contacts the ground again.

Question 7

Stride length

Answer 7

The interval between 2 sequential initial floor contacts from the same limb

Question 8

Step length

Answer 8

The interval between an initial contact from one foot to the initial contact of the other foot

Question 9

Heel strike

Answer 9

The onset of stance made by the contact of the heel onto the ground

Question 10

Toe off

Answer 10

The lift off of the big foot from contact point on the ground

Question 11

Ground reaction force

Answer 11

The force exerted by the ground of a body in contact with it

Question 12

Stance phase

Answer 12

The entire period during which the foot is on the ground

Question 13

Swing phase

Answer 13

The time the foot is in the air

Question 14

Loading response

Answer 14

Body weight transfer from initial contact through until the opposite limb is lifted for swing

Question 15

Mid stance

Answer 15

Initial phase of single leg support where momentum moves mass over forefoot.

Question 16

Terminal stance

Answer 16

Completes single leg support. Body weight moves ahead of forefoot

Question 17

Pre swing

Answer 17

Final phase of stance, represents functional commitment to initiating forward motion prior to swing phase

Question 18

Initial swing

Answer 18

The lift off the foot from the floor

Question 19

Mid swing

Answer 19

Middle area of swing when foot is opposite the stance foot

Question 20

Terminal swing

Answer 20

Last phase of swing in preparation for initial contact

Question 21

During gait lower limb muscles function to

Answer 21

• Produce appropriate movements required for locomotion
• Accelerate/decelerate body parts
• Stabilise body parts for efficient movement

Question 22

Hip motion range

Answer 22

from 30° flexion to 20° extension (total range 50)°

Question 23

Hip motion allows what

Answer 23

pelvis & trunk to remain erect whilst body weight moves over supporting foot

Question 24

Knee motion range

Answer 24

ranges from approx. 60° flexion to 0° extension (total range 55° to 60°)

Question 25

Knee motion allows what

Answer 25

• Key to stance stability
• Reduces the length of the swinging limb and hence facilitates foot clearance in swing phase

Question 26

Ankle motion range

Answer 26

ranges from 20° plantarflexion to 5° dorsiflexion (total range 25°)

Question 27

Ankle motion phase 1

Answer 27

Plantarflexion reduces impact of heel contact at loading response

Question 28

Ankle motion phase 2

Answer 28

Dorsiflexion through mid-stance to terminal stance facilitates advancement of body weight over foot

Question 29

Ankle motion phase 3

Answer 29

Plantarflexion prepares limb for swing phase by transforming extended knee into freely flexing joint

Question 30

Ankle motion phase 4

Answer 30

Dorsiflexion during swing allows for foot clearance

Question 31

Coronal pelvic motion is what

Answer 31

lift/drop around an AP axis

Question 32

Coronal pelvis motion activates what

Answer 32

contralateral (supported limb) gluteus medius and minimus limit drop during stance phase

Question 33

Failure of coronal pelvic motion causes what

Answer 33

Trendelenburg gait (weakness of hip abductors on stance leg)

Question 34

Sagittal pelvis motion is what

Answer 34

tilt around a transverse axis

Question 35

Trunk movements during gait

Answer 35

At thorax & shoulder

• Posterior (backward) over swinging limb
• Upper limb swings forward with contralateral lower limb

Question 36

Centre of gravity

Answer 36

imaginary point that represents the concentration of the weight of the body

• Can be inside or outside the body, dependent on body position
• Static anatomical position: CoG falls just anterior to the vertebra S2
• Is at its highest level during mid-stance phase of gait.

Question 37

Vertical movements of CoG

Answer 37

• Approx. 3-5 cm in amplitude
• Highest point: mid stance
• Lowest point: double support

Question 38

Lateral movements of CoG

Answer 38

• Due to lateral transference of body weight from one leg to the other
• Approx. 4cm total (2cm each side)
• Largest displacement: mid stance

Question 39

We need to limit the amount of movement of CoG to

Answer 39

• Minimise energy expenditure
• Limit wear and tear on musculoskeletal system

Question 40

Factors limiting movements of CoG
(vertical)

Answer 40

• Inversion/eversion of foot during stance -> limits inferior and superior excursion of CoG
• Plantarflexion @late stance phase -> limits inferior excursion of CoG
• Anterior pelvic rotation during swing -> limits inferior excursion of CoG
• Knee flexion during support phase -> limits superior excursion of CoG
• Anterior pelvic tilt during swing phase (with knee flexion @early swing) -> limit superior excursion of CoG

Question 41

Factors limiting movements of CoG
(lateral)

Answer 41

• Width of base of support