Normal Gait Mechanics Flashcards
What are the two main functions of the foot?
pronation and supination
What is the function for pronation?
adaptation, shock absorption and torque conversion from up the kinetic chain
What is the function of supination?
rigid lever used late in stance phase for stable propulsion
How long is the swing phase during gait cycle?
1/3 or about 0.4 secs
How long is the stance phase during gait cycle?
2/3 or about 0.6 seconds
What happens during initial contact of gait?
begins with lateral heel strike, supinated foot and heel acts as a rocker
What happens during loading response of gait?
foot absorbs impact from initial contact by subtalar pronation which unlocks mid tarsal joints
What happens during mid stance of gait?
SLS stance begins, ankle becomes rocker, COG begins to move over BOS, Hip and knee extension
ST joint begins to supinate to prepare for push off
What happens during terminal stance of gait?
SLS concludes, forefoot rocker, body moves ahead of BOS
What two phases of gait are DLS?
initial contact and pre swing
Where is one’s COG in DLS?
low and in the middle of BOS
Where is one’s COG in SLS?
High, and is lateral of BOS towards the stance leg
What is average angle of gait?
7 degrees of toe out should see 5th Met and maybe 4th from behind
What is average base of gait or BOS?
3.5 inches
What is average stride length?
4.5 feet, distance between two consecutive initial contacts of same foot
What is always consistent during subtalar pronation?
Calcaneal eversion
What occurs during OKC subtalar pronation?
calc EV, ABD, DF
What occurs during CKC subtalar pronation?
Calc EV, ADD/PF, tibial IR (moves based off Talus)
During CKC pronation what happens up the chain?
Calc EV, Talar ADD/PF, Tibial IR, knee flexion, HIP IR, APT, lumbar lordosis
During subtalar supination what is always consistent?
calcaneal inversion
What happens during OKC supination?
calc INV, ADD, PF
What happens at subtalar joint during CKC supination?
calc inv, ABD/DF, tibial ER
During CKC supination what happens up the chain?
calc inv , ABD/DF, tibial ER, knee ext, hip ER, PPT, decreased LL
During subtalar pronation how are the CC and TN joints aligned?
they become parallel to one another which allows for more mobility in the mid foot
During subtalar supination how are the CC and TN joints aligned?
they become stacked on top of one another which creates more rigidity and less mobility at mid foot
What is goal and ground force reaction during loading response?
shock absorption, adapt to terrain
GFR: vertical load of 110-125% BW, increases with increased cadence
What is goal and ground force reaction during mid stance?
foot needs to become more stable
GRF: 75% of BW
What is goal and ground force reaction during pre swing?
prepare for propulsion, Rapid ER as swing limb advances
GFR: 125% of BW
What is happening at femur during loading response?
30 of flexion moving into 10-20 extension, IR
decelerating by external rotators and glutes
limb rotation absorbed by STJ torque conversion
What is happening at femur during mid stance?
hip extends as momentum advances body, ER force created by swing of leg and opposite arm and helped by external rotators and glutes
What is happening at femur during terminal stance and pre swing?
hip extension, ER accelerated by ER and glutes
What happens at knee during loading response?
flexion for shock absorption, decelerated by quads, glutes and hammys
Tibial IR unlocks knee for STJ pronation
What is happening at knee during mid stance?
flexion to extension, decelerated by gastroc., tibial ER for STJ supination
What is happening at knee during pre swing?
flexion, accelerated by hamstring
What happens at ankle during loading response?
slight DF due to TA working during swing phase, then rapid PF decelerated by TA, EDL, EHL
What happens at ankle during mid stance?
DF as tibia advances over fixed foot, decelerated by gastric and soleus to prevent excessive DF
What happens at ankle during pre swing?
PF by gastric and soleus
During initial contact what is the position of 4 different LE joints?
Hip- flexed
knee- extended
ankle- DF
Subtalar- supinated
During loading response what is the position of 4 different LE joints?
hip- IR + extended
knee- flexed with tibial IR
ankle- PF
STJ- pronating
During mid stance what is the position of 4 different LE joints?
Hip- ER and extended
knee- extended tibial ER
ankle- DF
Subtalar- supinated
During propulsion phase what is the position of 4 different LE joints?
Hip- ER and extended
knee- extended tibial ER
ankle- PF
Subtalar- supinated
