Final Flashcards
Premise 2 of Six Determinants of Gait?
MINIMIZING THE AMOUNT THAT THE BODY’S COM IS DISPLACED from the line of progression
Six Determinants of Gait planes motion?
-Sagittal plane: flexion & extension
-Transverse/horizontal plane: pelvic rotation
-Frontal plane: lateral pelvic tilt
Premise 1 of Six Determinants of Gait?
Gait is the translation of the center of mass through space along a pathway requiring the LEAST EXPENDITURE OF ENERGY.
What does the six determinants theory state?
Energy costs during gait (vertical and horizontal displacements) is minimized by the six actions of the pelvis, hip, knee and ankle
What does the inverted pendulum theory state?
The stance leg is kept relatively straight during single support, functioning like an inverted pendulum
(The COM, located near the hip, travels in a series of arcs prescribed by each single support phase. The limb travels like a pendulum, thus does not require much energy)
What is the minimum gait velocity for better outcomes?
1.0m/s or more
What gait speed is bad? And what does it lead to?
0.7m/s or less (Increased risk of falls, limited community ambulator)
What gait speed predicts future risk of falls and hospitalizations?
0.6m/s or less
What gait speed shows a likelihood of discharge to SNF?
0.4m/s or less
What does gait speed indicate?
Fall prevention, hospitalizations and level of functional walking
When does double support occur (22%)
Initial contact and pre-swing/toe off
What should the stride length be for women/men?
0.67m women and 0.76m men
How to measure step width?
Mid point of calcaneus to mid
point of calcaneus
What is cadence?
of steps per min
How do you calculate gait velocity?
Cadence x SL = GV
What is the gait velocity for adults?
1.2 -1.4 m/s
What is joint moment?
The amount force that is required to stabilize or create movement in a joint axis
Initial contact
Critical event: Heel contact w/ ground
-Ankle: 0* (Heel rocker initiated)
-Knee: 0-5*
-Hip: 20* F
Loading Response
CRITICAL EVENT: Hip&knee stability/ankle PF
(shock absorption)
-Ankle: 5* PF (heel rocker initiated)
-Knee: 15* F
-Hip: 20* F (stability)
Midstance
Critical Event: controlled tibial advancement
-Ankle: 5* DF
(2nd ankle rocker)
-Knee: 5* F
(tibial advancement begins after midstance)
-Hip: 0*
(pelvis and hip are stabilized)
What phase is tibial advancement?
Midstance (Talocural joint)
Terminal Stance
Critical Event: Force generation for propulsion forward (controlled dorsiflexion with heel rise)
-Ankle: 0-5* (1st metatarsal = 30* E) (3rd ankle rocker emerges)
-Knee: 0-5* (prevent collapse)
-Hip: 20* E
*TRAILING LIMB: allows for greater step length
Pre-Swing/Toe-off
Critical Event: PASSIVE knee flexion to 40 degrees, ankle plantarflex
-Clear the leg!
-Ankle: 15* PF (1st metatarsal = 60* E)
-Knee: 40* F
-Hip: 10* E
Initial Swing
-Ankle: 5* PF
-Knee: 60* F
Hip: 15* F
Midswing
-Ankle: 0* (neutral)
-Knee: 25* E (rapid knee ext)
-Hip: 25* F
Terminal Swing
Ankle: 0* (neutral)
Knee: 0* (neutral)
Hip: 20* F
What position and how many degrees does the pelvis sit at during neutral, terminal stance and SLS?
-Neutral: APT @10*
(And tilts 4* more during terminal stance)
-SLS = PPT
During weight acceptance, what happens to the pelvis?
-Contralateral pelvis drops 4* (downward tilt)
In the frontal plane, what happens to the hip from IC to LR?
0-10* of adduction
What happens to the calcaneus BIOMECHANICALLY during LR?
Everts 5* & goes into pronation (shock absorption)
What happens to the calcaneus BIOMECHANICALLY during Terminal Stance?
-Subtalar decreases eversion from 5* to 2*
(Creates rigid forefoot level in terminal stance: moving toward supination)
(promotes 3rd rocker->forefoot rocker)
What happens to the pelvis in swing?
5* of pelvis forward
What happens to the pelvis in stance?
5* of pelvis retraction
What allows for a longer step/stride length in thee pelvis?
Pelvis rotation
What is Reciprocal Inhibition?
Allow a joint to freely move without the antagonist activating
What creates joint stability?
Co-activation
What does eccentric muscular activation in gait do?
Shock absorption and deceleration
What does the CPG do?
-On and off timing of motor activity during walking
Initial Contact muscles?
-Hip: Gluteus max and add magnus
-Knee: Quadriceps extend knee (Hamstrings contract to counteract contact torque)
-Ankle: Anterior Tibialis eccentric (Pretibial musculature)
Loading Response muscles?
-Hip: Lower fibers of gluteus maximus, adductor magnus and hamstrings are activated to counteract the flexor torque (Peaking are TFL, gluteus medius and minimus, and upper fibers of gluteus maximus to stabilize the frontal plane)
-Knee: Eccentric quadriceps activity
SHOCK ABSORBER (knee flex)
-Ankle: Eccentric contraction of pretibial Muscles (EHL,EDL,AT) Peak Anterior Tibialis activity (eccentric)
Tibial posterior stabilizes throughout stance phase Gastroc soleus activates in LATE LOADING RESPONSE
Midstance support muscles?
-Hip: No sagittal plane muscle activity with exception of gluteus maximus upper fibers
Gluteus medius provides frontal plane stability
*TFL provides stability (co-activation)
-Knee: Quadriceps provide dynamic knee stability up until midstance eccentric
-Ankle: Gastroc-soleus restrains the tibia, which allows forward progression of the tibia
*Soleus and gastroc control the forward progression of the tibia (eccentric control)
Terminal Stance muscles?
-Hip: TFL anterior fibers activate
-Knee: hamstrings
-Ankle: Gastroc-soleus muscle peaks in activity to prevent tibial collapse (providing propulsion) (Tibiablis Posterior, Peroneal Longus and Brevis provide stability)
When does push off-gastroc power peak?
Terminal stance
What stabilizes the hip during LR and MS?
TFL, Glute max and Glute med
Pre-Swing muscles?
-Hip: Adductor longus contributes to flex femur with rectus femoris -Knee: Gracilis for prep for knee flexion
-Ankle: Gastroc soleus ceases activity early in pre-swing
Initial Swing muscles?
Hip: Iliacus initial phase and stops, SARTORIUS and GRACILIS PEAK in activity Hamstrings come in in late mid-swing (co-activation at hip: decelerate)
-Knee: Biceps femoris short head, sartorius and GRACILIS peaks to flex knee
-Ankle: Pretibial muscles are active to initiate dorsiflexion: EDL AND EHL shows peak activity. AT continues to mid swing
Which hip muscle carries momentum forward?
Gracilis
Which ankle muscle carries momentum forward?
Pretibial muscles
Terminal Swing muscles?
-Hip: Hamstrings peak at their activity Hip stabilizers: lower fibers of gluteus maximus Adductor magnus to stabilize hip
-Knee: Quadriceps are concentrically activating In late terminal swing, the hamstrings will activate to reduce the acceleration of the quads
-Ankle: Pretibial muscles are concentrically active