week 8

Question 1

what is gait

Answer 1

refers to the manner or style of walking.

Question 2

Stance

Answer 2

foot in contact with ground

Question 3

swing

Answer 3

no ground contact

Question 4

Gait cycle

Answer 4

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 5

Stride length

Answer 5

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

Question 6

Step length

Answer 6

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

Question 7

Stance phase

Answer 7

the entire period during which the foot is on the ground.

Question 8

Swing phase

Answer 8

the time the foot is in the air.

Question 9

Initial contact

Answer 9

the instant the foot makes contact with the ground. (Previously be referred to as heel strike)

Question 10

Loading response

Answer 10

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

Question 11

Mid stance

Answer 11

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

Question 12

Terminal Stance

Answer 12

completes single leg support. Body weight moves ahead of forefoot.

Question 13

Pre-swing

Answer 13

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

Question 14

Initial Swing

Answer 14

the lift off the foot from the floor.

Question 15

Mid Swing

Answer 15

middle area of swing when foot is opposite the stance foot.

Question 16

Terminal Swing

Answer 16

last phase of swing in preparation for initial contact.

Question 17

Heel strike

Answer 17

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

Question 18

Toe off

Answer 18

the lift off of the big toe from contact point on the ground.

Question 19

Ground reaction force (GRF)

Answer 19

the force exerted by the ground on a body in contact with it.

Question 20

Hip motion

Answer 20

• Ranges from 30° flexion to 20° extension (total range 50)°
• Hip motion allows pelvis and trunk to remain erect whilst body weight moves over supporting foot.

Question 21

knee motion

Answer 21

• Ranges from approx. 60° flexion
  to 0° extension (total range 55° to
  60°)
• Key to stance stability
• Reduces the length of the swinging limb and hence facilitates foot clearance in swing phase.
  Extending

Question 22

Ankle motion

Answer 22

• Ranges from 20° plantarflexion to 5° dorsiflexion (total range 25°)
• Plantarflexion reduces impact of heel contact at loading response (1).
• Dorsiflexion through mid-stance to terminal stance facilitates advancement of body weight over foot (2).
• Plantarflexion prepares limb for swing phase by transforming extended knee into freely flexing joint (3).
• Dorsiflexion during swing allows for foot clearance (4).

Question 23

Pelvic motion (coronal)

Answer 23

• Movement (lift/drop) around an AP axis, along coronal plane
  *
  Tendency to for pelvic drop on the side of the swing (non supported) limb
   Activation of contralateral (supported limb) gluteus medius and minimus limit drop during stance phase
   Failure -> Trendelenburg gait (weakness of hip abductors on stance leg)

Question 24

Pelvic motion (sagittal)

Answer 24

• Movement (tilt) around a transverse axis
  Very small total amount of tilt (2-4 degrees)

Question 25

Centre of gravity (CoG)

Answer 25

• 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 26

Trunk movements during gait

Answer 26

At thorax & shoulder
* posterior (backward) over swinging
limb
 upper limb swings forward with contralateral lower limb

Question 27

Centre of Gravity vertical movement- highest and lowest point

Answer 27

Vertical movements of CoG
* Approx. 3-5 cm in amplitude
* Highest point: mid stance
* Lowest point: double support

Question 27

Centre of Gravity lateral movement

Answer 27

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

Question 28

Factors limiting movements of CoG

Answer 28

• 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 29

initial contact

Answer 29

• AIM: position limb for stance position

Question 29

Load response

Answer 29

• AIM: shock absorption, weight acceptance

Question 30

midstance aim

Answer 30

• AIM: stability, progression over foot

Question 31

Terminal stance aim

Answer 31

• AIM: progression of body beyond supporting foot

Question 32

pre swing stage aim

Answer 32

• AIM: position limb for swing phase

Question 33

Initial swing phase aim

Answer 33

• AIM: foot clearance, advancement of limb

Question 34

Mid swing phase aim

Answer 34

• AIM: foot clearance, advancement of limb

Question 35

Terminal (late) swing phase aim

Answer 35

• AIM: complete advancement, prepare for contact