Foot/Ankle Function During Gait Flashcards
(27 cards)
Foot and ankle functions (3)
kinetics (forces/torques)
kinematics ( motion)
Muscle actions
Saggital plane kinematics
INITIAL CONTACT
[not a phase; just end TR/beginning LR]
Ankle: NEUTRAL- facilitates HEEL ROCKER
technically 90 degrees–> 0 deg DF; 0 deg PF
Saggital plane kinematics
LOADING RESPONSE
Ankle: from 0 deg –> 10 deg PF
Part of heel rocker mechanism
Objective: forward progression
Critical event: 10 deg PF
Saggital plane kinematics
MID-STANCE
Ankle: 10 deg PF –> 5 deg DF
total range: 15 deg DF
Objective: progression of COM OVER BOS
Critical event: 5 deg DF
Saggital plane kinematics
TERMINAL STANCE
Ankle: 5 deg DF –> 10 deg DF
- max DF range in cycle
range: 5 deg DF
Objective: progression of COM BEYOND BOS
Critical event: 10 deg DF
forefoot/toe rocker- DF occurs w/ heel off ground
Saggital plane kinematics
PRE-SWING
Ankle: 10 deg DF–> 20 deg PF
range: 30 deg PF
most rapid ROM of ankle!
no objective for foot/ankle
Saggital plane kinematics
INITIAL SWING
Ankle: 20 deg PF –> 5 deg PF
range: 15 deg DF
no objective because hip/knee key to foot clearance
Saggital plane kinematics
MID-SWING
Ankle: 5 deg PF- neutral
reange: 5 deg DF
Objective: foot clearance
Critical event: NEUTRAL- foot has to be neutral as knee starts to extend or you drage
Saggital plane kinematics
TERMINAL SWING
Ankle: remains neutral
Objective: preparing limb for stance/heel contact
Critical event: neutral angle
What happens in frontal plane kinematics of gait
foot pronation/supination
occurs rear and midfoot for this class :)
Frontal plane kinematics
INITIAL CONTACT
foot: supination
3-5 deg
Frontal plane kinematics
LOADING RESPONSE
Foot: pronation
4-6 deg rearfoot eversion (rotates to floor)
Frontal plane kinematics
MIDSTANCE-TERMINAL STANCE
foot: pronation to neutral (or slight inversion/sup)
Objectives of frontal plane foot motion PRONATION
Loading response/Midstance
- shock absorption: pronation unlocks midtarsal joints so foot is MOBILE ADAPTOR- cusions impact
- Stance stability: pronates to get full foot contact with floor
Objectives of frontal plane foot motion SUPINATION
Midstance/Terminal stance
-faciliates progression of COM beyond BOS (forefoot rocker)- locking of midtarsal joints- RIGID LEVER
Foot pronation effect on tibia
Pronation facilitates Tibial INTERNAL ROTATION
talus internally rotates- makes tibia
frontal plane foot motion COUPLED w/ tibial transverse motion!
Saggital Muscle Control
LOADING RESPONSE
-Plantarflexion moment [torque] (vector behind ankle)
Muscles act ECCENTRICLLY to control slow PF/oppose GRF with DF
-Dorsiflexors (eccentric):
Tib ant (primary)
Extensor hallicus longus
Extensor digitorum
Saggital Muscle Control
MIDSTANCE
-Dorsiflexion moment (vector like string pull up)
COM moves foward gives ankle rocker
-PF (eccentric)
Gastroc
Soleus
Saggital Muscle Control
TERMINAL STANCE
-Increasing Dorsiflexion moment (lever arm increasing)
COM moves further over foot gives forefoot rocker
-PF (eccentric)
Gastroc
Soleus
Saggital Muscle Control
PRE-SWING
-Reducing dorsiflexion moment (lightens up as weight transfers to other side)
NO push off
-PF (concentric)- 20deg
Residual reducing calf demand
Saggital Muscle Control
INITIAL SWING
-Plantar flexion moment- gravity driven
Gravity wants to pull foot into PF so DF to overcome
-DF (concentric)
Tib ant
Extensor hallicus longus
Extensor digitorum
Torque vs. Motion in Muscle control
torque tells what muscle group is on (opposite of what torque vector is)
IF AGAINST TORQUE- concentric
motion tells if eccentric, concentric, isometric
Saggital Muscle Control
MID-SWING
-Plantar flexion moment- gravity driven
same as initial swing
-DF (concentric)
Tib ant
Ext Hallicius long
Exten digitorum
Saggital Muscle Control
TERMINAL SWING
-Plantar flexion moment- gravity driven
ankle is neutral
-DF (isometric)
tib ant
exten hal long
exten dig
