Normal and Pathological Gait

Question 1

Describe human gait (4)

Answer 1

bipedal
reciprocating
upright
terrestrial

Question 2

What are the 4 functional requirements of gait

Answer 2

shock absorption
stability
propulsion
energy conservation

Question 3

How is shock absorption achieved and why is it important?

Answer 3

through controlled shortening of the joints

prevent joint damage

Question 4

What is joint stability?

Answer 4

preventing bucking of joints against gravity

Question 5

what is global stability?

Answer 5

keep centre of mass within base of support

Question 6

Why is foot clearance important?

Answer 6

prevent stumbling

Question 7

What 4 aspects of gait contribute to stability?

Answer 7

step width
step length
cadence
speed

Question 8

What is propulsion?

Answer 8

moving centre of mass forward, extension of lower limbs

Question 9

What is normal toe clearance in walking?

Answer 9

~1.2cm

Question 10

What are the 4 components of pathological gait

Answer 10

inadequate shock absorption

unstable - fall risk, needs aids

impaired propulsion - compensation

excessive energy expenditure - reduction in endurance

Question 11

Whys is gait measurable?

Answer 11

it is cyclic and repeatable

Question 12

What is stride time?

Answer 12

time between one initial contact of one foot to the next initial contact of the same foot

Question 13

What is the relationship between stride time and cadence?

Answer 13

stride time = cadence^-1

Question 14

What is double support?

Answer 14

point where one part of each foot is in contact with the ground

Question 15

What proportion of gait is stance/swing phase?

Answer 15

stance 60%

swing 40%

Question 16

What is a gait model?

Answer 16

a simplified representation of a complex process in order to measure/understand

Question 17

Describe hip motion during the gait cycle

Answer 17

initial contact - 30 degrees of flexion

extension to 15 degrees

flexes again spring swing phase to around 40 degrees and back to 30 degrees at next initial contact

Question 18

Describe knee motion during the gait cycle

Answer 18

0 at initial contact

10 degrees of flexion at foot flat to 0 in mid stance

extension through terminal stance and toe off to around 60 degrees to allow foot clearance

Question 19

Describe ankle motion in the gait cycle

Answer 19

initial plantar flexion to slight dorsiflexion

plantar flexion increases though terminology stance up to toe off when the foot dorsiflexes to clear the ground

Question 20

What Newton law applies to the creation of ground reaction force?

Answer 20

every action has an equal and opposite reaction

Question 21

What does ground reaction force position relate to?

Answer 21

acceleration of the centre of mass

Question 22

What does anteroposterior GRF relate to?

Answer 22

deceleration

Question 23

What does postero-anterior GRF relate to?

Answer 23

acceleration

Question 24

What are joint moments?

Answer 24

turning effect about a point

m = F x d

Question 25

What is an example of a moment being balanced by:

muscle
ligament
joint foce

Answer 25

calf muscles
MCL/LCL in the knee
knee joint force in walking

Question 26

What is the equation for power?

Answer 26

power = moment x angular velocity

Question 27

Describe how power generation and power absorption occur

Answer 27

power generation - internal moment and angular velocity in same direction

power absorption - internal moment and angular velocity in opposite directions

Question 28

What is the function of muscles during gait?

Answer 28

force actuators

concentric contractions generate force

eccentric contractions accept force