LECTURE 3: GAIT

Question 1

Normal gait sequence:

Answer 1

IC
LR
midstance
terminal stance
pre swing
initial swing
mid swing
terminal swing

Question 2

What are the 3 functional tasks of gait?

Answer 2

1. weight acceptance
   (IC, LR)
2. single limb support (midstance, terminal stance)
3. swing limb advancement
   (presw, initial swing, midswing, terminal swing)

Question 3

biomechanical subcomponents of gait

Answer 3

1. stance control
2. limb advancement
3. propulsion
4. postural stability

Question 4

What are proportions of single limb vs double limb support?

Answer 4

Single limb support: 80%
Double limb support: 20%

Question 5

What do rockers do?

Answer 5

smooth transitions over foot

Question 6

4 functional rockers:

Answer 6

heel
ankle
forefoot
toe

Question 7

normal gait velocity

Answer 7

82 m/min or 1.2-1.4 m/sec or 2.7-3.1 mph

Question 8

normal gait cadence

Answer 8

113-116 steps/minute

Question 9

BOS normal gait

Answer 9

2-4 inches

Question 10

toe out in normal gait

Answer 10

7 degrees

Question 11

stance phase is __% of gait cycle

Answer 11

62%

Question 12

swing phase is _% of gait cycle

Answer 12

38%

Question 13

INITIAL CONTACT

Answer 13

hip: 20 degrees flexion
knee: 5 degrees flexion
ankle: 0 NEUTRAL

*GRF is anterior to hip/knee, flexor moment! hip extensors counteract this

Question 14

what is the critical event at IC?

Answer 14

HEEL FIRST CONTACT

Question 15

What mm are firing during IC?

Answer 15

HIP EXTENSORS to counter extensor moment
knee: quads to prep for loading response
ankle: isometric pre-tibialis

Question 16

What is critical event of LR?

Answer 16

hip stability
controlled knee flexion
ankle PF (heel rocker)

Question 17

What could you see with weak quads?

Answer 17

SEVERE knee buckle LR
hyperextended LR

Question 18

LOADING RESPONSE

Answer 18

Hip
– 20 degrees flexion
– Muscle activity: hip extensors/abductors
* Knee:
– 15 degrees flexion
– Muscle activity: eccentric quadriceps
* Ankle:
– 5 degrees PF
– Muscle activity: eccentric pre-tibials
– Heel rocker

Question 19

GRF in loading response

Answer 19

anterior to hip
posterior to knee

Question 20

KEY MUSCLES ACTIVATED DURING LOADING RESPONSE

Answer 20

hip extensors(glutes)
eccentric quads
eccentric pre-tibs (may see foot drop/forefoot contact or foot slap if gone)

Question 21

what is happening in midstance?

Answer 21

hip = abductors
knee = 5 deg flexion
ankle = goes from PF to 5 deg DF
ANKLE ECCENTRIC PLANTARFLEXORS
ANKLE ROCKER

Question 22

critical event during midstance:

Answer 22

controlled tibial advancement

Question 23

what are you looking for in terminal stance?

Answer 23

BIG V, trailing limb angle (ROM at hip for hip extension)
***big big big torque for calf eccentrics

Question 24

if calf is weak during terminal stance, what would you see?

Answer 24

1. low heel rise
2. decreased V
3. SHORT SHUFFLE STEP –> STEP EARLY and miss terminal stance bc they dont trust the stance PF to hold whole body weight

Question 25

Terminal Stance

Answer 25

Hip
– 20 degrees extension
– Muscle activity: none
* Knee:
– 5 degrees flexion (neutral)
– Muscle activity: none
* Ankle:
– 10 degrees dorsiflexion
– Muscle activity: eccentric plantarflexors
– Forefoot rocker
* Toes:
– 20-30 degrees extension

Question 26

critical event of terminal stance

Answer 26

*Critical event: Calf muscles control ankle DF allowing heel rise; trailing limb

Question 27

GRF of terminal stance

Answer 27

anterior to knee and posterior
to hip

Question 28

preswing phase critical event

Answer 28

*Critical event: passive knee flexion; ankle PF assists with passive knee flexion

Question 29

hallmark of preswing phase

Answer 29

PASSIVE! need good terminal stance V for good

Question 30

how much DF ROM do you need for stance?

Answer 30

10-12 degrees

Question 31

how much ROM DF do you need for swing?

Answer 31

0!!!!! neutral

Question 32

preswing phase:

Answer 32

• Hip:
  – 10 degrees extension
  – Muscle activity: adductors, minimally to help bring limb in a little
• Knee:
  – 40 degrees flexion PASSIVE
  – Muscle activity: none
• Ankle:
  – 15 degrees plantar flexion
  – Muscle activity: none
• toes:
  – 55-60 degrees extension
  –TOE ROCKER

Question 33

initial swing

Answer 33

• Hip:
  – 15 degrees flexion
  – Muscle activity: concentric hip flexors
• Knee:
  – move from 40 to 60 degrees flexion
  – Muscle activity: knee flexors
• Ankle:
  – 15 to 5 degrees plantar flexion
  – Muscle activity: pre-tibials concentrically

Question 34

what is important in initial swing?

Answer 34

Quick concentric hip flexors is important for GOOD LIMB ADVANCEMENT
*critical event: hip flexion 15 deg, knee flex to 60 deg

Question 35

midswing phase

Answer 35

Hip:
– 25 degrees flexion
– Muscle activity: concentric hip flexors initially
then hamstrings eccentrically

• Knee:
  – 25 degrees flexion
  – Muscle activity: silent then hamstrings initiate
  to eccentrically decelerate the lower limb
• Ankle:
  – Neutral
  – Muscle activity: isometric pre-tibials

Question 36

what is important to midswing?

Answer 36

Hamstrings ECCENTRICALLY turn on to slow down lower limb
*Critical event: Further hip flexion; dorsiflexion to neutral

Question 37

terminal swing phase

Answer 37

• Hip:
  – 20 degrees flexion
  – Muscle activity: Hamstrings
  eccentrically decelerate the lower limb
• Knee:
  – Neutral (5 degrees)
  – Muscle activity: quadriceps
  concentrically; Hamstrings
  eccentrically decelerate the lower limb
• Ankle:
  – Neutral
  – Muscle activity: isometric pre-tibials

Question 38

what is IMPORTANT in terminal swing?

Answer 38

Hamstrings are still on to decelerate lower limb: IF HAMMIES ARE NOT TURNING ON ECCENTRICALLY, WILL SEE A FAST KICK OUT/FLING
*CRITICAL event: knee extension