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
What muscle propulses the body fwd?
Ankle PF (Gastroc-soleus)
Trunk deviations?
-Lateral lean L/R
-LATERAL LEAN
BACK/FORWARD
-LATERAL ROTATION L/R
Pelvis deviations?
-Excessive pelvic rotation
-Anterior pelvic tilt
-Pelvic elevation (during swing phase provides a method to swing limb forward)
Gluteus medius and pelvic/trunk deviations?
Abductor lurch or gluteus medius gait: lateral lean toward on involved side
Trendelenburg gait: contralateral pelvic drop
-Two distinct hip deviations: weak gluteus medius
-Pelvic drop from leg length discrepancy: ipsilateral pelvic drop (short limb syndrome)
Waddling gait: bilateral pelvic drop
Hip deviations?
-Gluteus maximus gait
-Hip hike w/ circumduction
-Hip circumduction (amputee)
Knee deviations?
-Knee hyperextension (SLS): recurvatum
-Knee flexion (SLS) during stance
-Knee varus (SLS)
Ankle deviations?
-FOOT DROP (during swing phase)
-Heel off gait (during LR or MS)
-CALCANEAL GAIT: FLAT FOOT GAIT
-VAULTING: EXCESSIVE PF DURING STANCE PHASE
What is the normal foot progression angle in adults?
13-15*
Who is more likely to have an in-toe gait?
Children under 4 years old
Femoral anteversion
Hip IR more than 40*
What is the cause of the ipsilateral Trendelenburg?
Weak hip abductors
Purpose of orthotics?
Control abnormal compensatory movements of the foot by bringing the foot to the floor (surface)
-Create a biomechanical
balanced kinetic chain by
controlling/reducing pathologic
motion in the foot and leg by
maintaining the foot in or close to
subtalar neutral position.
When does the subtalar go into full pronation?
IR->LR
What issues can over-pronation cause?
-Anterior Pelvic Tilt
-Femur IR
-Valgus Knee
-Medial rotation talus
-Adduction and plantarflex talus
-Calcaneal eversion
What is a UCBL best used for?
Over-pronation/calcaneal eversion
Who is an AFO prescribed for?
-weakness
- stroke
-cerebral palsy
- head injury
-peripheral neuropathy
-alignment
-spinal cord injury
-progressive disease
An orthosis is most comfortable
and effective when
- Pressure = Force/Area
- Control direction of primary force and direction of counterforces
What is the AFO used for?
ONLY FOR SWING PHASE
(Assist with controlled lowering of the foot during loading response in stance as part of the first/heel rocker)
What is the Solid AFO best used for?
Spasticity (Resists PF) and supports calaneus
Neutral ankle
What is the disadvantage of the solid AFO?
Does not always support three rocker phases (keeps ankle @neutral)
Impairment in Neurologic Disorders
Abnormal tone, loss of selective motor control, sensory loss, alignment, balance/postural control and contractures
When do you initiate gait training?
- If they can stand on the affected limb and PWB on affected limb
-Can they understand and follow directions? Can they control their trunk and head? Do they have protective responses? - Parallel bars for affected limb instability
- Cane or quad (IF they pt can properly advance)
- Neurologic clients: stand on involved side, wide BoS and move w/ pt
What happens when someone has had a CVA?
-Loses heel contact, wobbles during loading (Knee hyper-extends when they are REALLY weak)
-Terminal stance: loss of hip extension
What happens the longer you stay in SLS?
The longer your contralateral step length will be
(More trailing limb and sensory input)
What are the most important determinants in Gait in persons with CVA
- Single Limb Stance on affected side: affected limb duration increases contralateral step length. 2. Single Limb Advancement: Knee flexion during mid- swing: allows for ease of foot clearance. Prevents swing limb deviations and decreases duration of swing.
- Plantarflexion Range of motion
- Standing Balance
Gait Characteristics in Parkinson’s disease
Early disease markers
1. Reduced step length
2. Amplitude of arm swing: earliest gait detection
3. Interlimb asymmetries
4. Increased duration in double time
5. Reduced gait width
Later disease markers
1. Shuffling steps: festinating gait
2. Freezing of gait (FOG)
What is Equinas Gait in children?
***Unable to effectively WB
-Hips IR (skeletal-young)
-Knees in flexion
What did Sherrington discover?
We don’t need higher brain influence to walk and removing sensory input on both sides resulted in pattern remains.
How does walking happen? And what structure don’t we need to walk?
Emotions and voluntary decisions. We don’t need the cortex to walk
Gait factors during 1 years old
*Locomotion pattern (CPG) is innate
- Postural control in standing (at tabletop)
*Motivation and navigation toward a distant object
-Standing on one leg: stance phase stability (cruising)
-High guard posture
What sensory contributions are there in children?
-Stretching of the hip flexors
-Step length, appropriate frequency, contributions of loading limbs (pressure sensors and standing for long periods)
What 2 things happen with the muscular system as we age?
-Loss of muscle mass after 60 yrs old (Especially type II fibers)
*-Sarcopenia or loss of muscle mass
What 2 things happens to our skeletal system as we age?
-Loss of vertebral body height
-Increased risk of fracture
What happens to our sensory receptors w/ Type II diabetes?
Sensory nerve fiber loss; loss of tactile sensation
What system makes up our postural control?
Visual system
*What is the purpose of the Vestibular system (“Use it or lost it”)?
-Acceleration (fwd/up/down)
-Head rotation (Speed and movement)
*What response is lost in the elderly population?
Protective responses
-Reduced ankle & hip strategy
-Reduced speed of protective arm extension
Parachute response (infant)
*What factor is linked to dementia?
Gait speed
Most likely cause for WA-Ankle: Excessive INV/Foot contact on IC
Overactivity of TA, TP or soleus
(Lack of selective motor control->unable to clear foot)
Most likely cause for SLA-Knee: Limited flexion
Extensor hypertonicity
(Lack of selective motor control->unable to clear foot)
Most likely cause for SLS-Hip (terminal stance): inadequate extension (lack of trailing limb)
Lack of selective motor control & unable to take demand of GrF
*3 methods of gait measurement
- Kinetics (Internal & external forces)
- Kinematics (Gait phases, ROM, muscle activity)
- Spatial Temporal (Velocity and step length)
What 3 things does Kinetics refer to?
- GrF (external force)
- *Moments (force that causes rotation around a joint)
Internal * external moments - Power (watts) = Force*time
(Concentric vs. eccentric)
What phase (stance or swing) the body accept greater force?
Stance phase
*Internal moments
- Internal moments are the total amount of force created by muscle/joint capsules/fascia
- Extensor moments: support for body on surface (quads, gastroc/soleus)
- Flexor moments: pull away from surface (illopsoas and dorsiflexors)
*What is “power” in gait kinetics?
*-Power=energy/time
-More power when it’s performed faster
-Power created=concentric (positive power)
-Power absorbed=eccentric (negative power)
What happens to hip force w/ a stroke pt?
The hip is retracted (less force produced)
Clinical implications of power in normal gait?
-PF: propulsive force (during push-off)
-Hip flexors: propulsive force (during pull-off)
Knee power is relatively low (usually negative, showing eccentric activity in knee extensors or flexors))
How would arm swing affect gait in the hip?
Retraction and protraction of hip increases
More power
=
Greater step length
What is postural control?
-Controlling the body’s position in space for the
dual purposes of stability and orientation (neurologic basis of
control= sensory, motor and biomechanics)
What is postural orientation?
ability to maintain an appropriate
relationship between the body segments, and between the body
and environment for a task (relationship posture and task)
What is CoM?
point that is the center of the body mass
What is BoS?
area of the body that is in contact with the
support surface
What is CoG?
vertical projection of the COM
*What is the ideal postural alignment?
*-Controlling the CoM relative to the BOS
*-CoM point: anterior to S2
-CoM should fall within BoS (requires the least muscular effort)
*Key points about CoM
-As the COM is not a physical entity but is a virtual point in space that depends on
the position of all body segments
-*If the nervous system controls the COM, it must be able to estimate the
position of the COM using information from the various sensory receptors
-The key variable controlled by the
CNS during postural control is the COM
The sensory
feedback from muscle spindles, joint receptors, somatosensory, vestibular helps CoM
What is the Adam’s test for?
Scoliosis
Sagittal key landmarks for posture?
Ear lobe, greater trochanter of femur, anterior to center of knee joint and anterior to lateral malleolus
*What muscles are active in quiet (static) standing?
Gastroc/soleus, erector spinae, abdominals, paraspinals
What kind of muscles are tight and weak in an anterior pelvic tilt?
Tight: Hip flexors
Weak: Hip extensors
What happens to the knee w/ an Anterior pelvic tilt (Swayback)?
Hyperextended hips and knees
*Major factors in dynamic postural control?
-Biomechanical alignment for static conditions
-Muscle groups work together to maintain position
-Organization of firing pattern based upon task
-Task that the individual performs adapts to CoM, BoS and CoG
This shows changes in COM
*-Sensory systems play a large role in dynamic posture
Postural strategies for adults?
Ankle strategy
-Muscular strategies in adults are organized into synergies
In children at 7 years: adult
like strategies
-Somatosensory becomes
predominant
-Muscular activation patterns
*What are the 4 postural controls: 4 States?
-Static Steady State (Sitting/Standing)
-Dynamic Steady State (Steady position while walking)
-Proactive (anticipatory; prep for predicted change in balance)
-Reactive balance (Responding to an unexpected perturbation)
*What are the elements of postural control?
-Biomechanical alignment
-Sensory feedback
-Muscular activation
*What are the sensory aspects of postural control?
-Somatosensory (Prorioception, kinethesia, or tactile)
-Vestibular
-Vision
Muscle spindle role in Proprioception/Kinesthesia?
Awareness of movement (speed and length)
GTO role in Proprioception/Kinesthesia?
Force or heaviness in objectives or creation of force
Joint capsule/Joint receptors role in Proprioception/Kinesthesia?
similar to skin: information
regarding joint movement
*What is sensorimotor control?
Integration (integrated
system for posture)
a. Uses various systems to
keep posture upright and
alignment
-Vision
-Cervical proprioception
-Vestibular System
*Where does the CNS take information from?
The CNS takes info form the sensorimotor cortex and cervical spine
What do the automatic motor responses react from?
Direction of change, force and postural position
What kind of muscular response (synergistic) is created automatically?
Organized, on-time, spatially organized and w/ the correct force.
