Lecture foot and ankle

Question 1

at Initial contact the ankle is?

Answer 1

Neutral, and facilitates heel rocker for forward progression

Question 2

in loading response the ankle is?

Answer 2

• 0-5 PF
• part of heel rocker mechanism
• Facilitates the objective of forward progression

Question 3

in mid-stance the ankle is?

Answer 3

• 5 PF to 5 DF

- Facilitates the objective of progression of COM over the BOS

Question 4

What forward progression phase does loading response include?

Answer 4

• heel rocker: a pivot point about the calcaneus, for tibia to roll over

Question 5

What forward progression phase does mid-stance include?

Answer 5

• ankle rocker: 10 degree arc of motion -> allows forward progression

Question 6

in terminal stance the ankle is?

Answer 6

• 5-10 DF

- facilitates the objective of progression of COM beyond BOS

Question 7

what forward progression phase does terminal stance include?

Answer 7

• forefoot/ toe rocker: heel comes off ground, allows COM to progress beyond BOS

Question 8

in pre-swing the ankle is?

Answer 8

• 10DF - 20 PF (30 degree arc of motion!)

there is no objective (initiating limb advancement occurs at the hip)

Question 9

in initial swing the ankle is?

Answer 9

• 20 PF to 5 PF (going towards DF)

Question 10

in mid swing the ankle is?

Answer 10

• 5PF to 0 (neutral)

- facilitates the objective of foot clearance !

Question 11

in terminal swing the ankle is?

Answer 11

• Neutral

- facilitates the objective of preparing the limb for stance (heel contact)

Question 12

Frontal plane: initial contact the foot is?

Answer 12

• foot is supinated 3-5 degrees

Question 13

frontal plane: loading response foot is?

Answer 13

• foot is pronated

- 4-6 degrees of rearfoot eversion

Question 14

frontal plane: midstance-terminal stance foot is?

Answer 14

• foot is pronated to neutral

Question 15

what is the objective of frontal plane foot pronation in loading response/midstance?

Answer 15

• shock absorption - pronation “unlocks” the midtarsal joints. therefore increases stance stability because more foot contact with the floor

Question 16

what is the objective of frontal plane foot supination in loading response/midstance?

Answer 16

• facilitates progression of COM beyond BOS(forefoot rocker)

- supination –> locks midtarsal joints turning foot into a “rigid lever”

Question 17

what couple motion does foot pronation induce?

Answer 17

• foot pronation and tibial internal rotation happen together

Question 18

Critical events during loading response ankle?

Answer 18

• Plantarflexion moment (external) controlled by internal response by
• Dorsiflexors (eccentric) –> Tibialis Anterior, EHL and EDL

Question 19

Crit events during midstance ankle?

Answer 19

• Dorsiflexion moment (external) controlled by internal response by
• Plantarflexors (eccentric) –> gastroc and soleus

Question 20

Crit events during terminal stance ankle?

Answer 20

• increasing dorsiflexion moment (external) controlled by internal response
• Plantarflexors (eccentric) –> Gastroc and Soleus

(muscle demand here is greater than in midstance due to COM is at forefoot)

Question 21

Crit events during pre-swing ankle?

Answer 21

• Reducing dorsiflexion moment (due to shifting body weight to other limb)
• reducing calf demand (concentric)
• no push off

Question 22

crit events during initial swing ankle?

Answer 22

• plantarflexion moment (gravity driven)

- Dorsiflexors (concentric) by the TA, EHL, ED

Question 23

crit events during mid swing ankle?

Answer 23

• plantarflexion moment (gravity driven)
• dorsiflexors (concentric) - TA, EHL, ED

carry over from initial swing

Question 24

crit evens during terminal swing ankle?

Answer 24

• Plantarflexion momnt (gravity driven)

- Dorsiflexors (isometric !) TA, EHL, ED

Question 25

which muscles dynamically control foot pronation during loading response?

Answer 25

• TP, TA, FHL, EDL

Question 26

pronation to supination: midstance-terminal stance

Answer 26

• Necessary for adequate forefoot rocker in terminal stance

- requires concentric action of invertors: TP, FHL, FDL