Gait Flashcards
Gait Variables
-Temporal-spatial
-kinematic
-kinetic
Temporal-spatial consist of
-velocity: rate of linear forward motion (m/s)
-cadence: number of steps/min
-stride length: heel strike to ipsilateral heel strike
-step length: heel strike to contralateral heel strike
-step width: width of BOS
Kinematic gait variables
-sagittal plane (flex/ext)
-frontal plane (ab/add)
-transverse plane (rotation)
Kinetic gait variables
-forces (vertical, fore-aft, medial/lateral)
-moments, power
-center of pressure
What are the phases of the gait cycle and the percentages?
Stance phase (60%)
-IC (0%)
-LR (0-10%)
-Midstance (10-30%)
-Terminal stance (30-50%)
-Preswing (50-60%)
Swing Phase (40%)
-Initial swing (60-73%)
-Midswing (73-87%)
-Terminal swing (87-100%)
Double limb support phases?
-IC
-LR
-Preswing
Single limb support phases?
-Midstance
-Terminal stance
Walking speed is considered the _____ vital sign?
Sixth
-1.4m/s to cross the road
-0.8-1.3m/s - community amubulator
-0.4-0.8 m/s- limited community ambulator
-0-0.4m/s - household walker
1 stride is equal to?
1 gait cycle
What are the primary forces that control walking?
Internal forces
-internal muscle forces
External forces
-Gravity (body weight)
-Air resistance
-GRF
What is newton’s 1st law of motion?
every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied (kinetics of walking)
Etiologies of GRF?
-Acceleration of the body’s center of mass
-inertia
-muscle forces
-gravity
-ligaments/bones
What is newton’s 2nd law of motion?
F=ma
GRFs in gait?
forces applied to the body by the ground, opposing forces applied to the ground during a step
What is newton’s 3rd law of motion?
Every action there is an equal and opposite reaction
Which forces of gait produces an external torque/moment?
External forces
-GRF
-Can be measured using force plates
Which forces of gait produces an internal torque/moment?
Internal forces
-usually in response to external torque created by GRF
-control or generate movement
-possible contributions from ligaments, joint capsulse, muscles, or bony structures
What functional tasks of gait occur during stance phase?
-weight acceptance
-single limb support
What functional tasks of gait occur during swing phase?
-foot clearance
-swing limb advancement
What are the 3 tasks of gait?
-Weight acceptance
-Single limb support
-Swing limb advancement
Weight acceptance occurs at what phase of gait?
IC and LR
Initial contact (0%)
-the moment the foot strikes the ground
-Ankle: held at neutral
-Knee: extension (5 deg flex), provides stability
-Hip: Peak 20 deg of flex, positioned for optimal fwd progression and stability
-Critical Event: heel contact
Loading Response (0-10%)
-shock is absorbed while forward momentum is preserved
-foot-flat position is achieved
-Ankle: Pre-ti muscles eccentrically control PF (5 deg of PF), subtalar eversion, 1st heel rocker
-Knee: 20 deg of flex for shock absorption. Quads active to control knee flexion
-Hip: maintained 20 deg flex. Hip extensors active for stability
-CRITICAL EVENT
—pre-tib eccentric control of PF
-Quads active to control knee flex
-Hip extensors for stability
Single limb support occurs at what phase of gait?
-Midstance
-Terminal Stance
Midstance (10-30%)
-body progresses over foot in controlled manner.
-contralateral limb provides momentum
-Ankle: DF controlled eccentrically by gastroc/soleus. 2nd ankle rocker
-Knee: extension
-Hip: neutral
-CRITICAL EVENT: DF controlled eccentrically by gastroc/soleus
Terminal Stance (30-50%)
-progression of body beyond the support food.
-limb/trunk stability
-Ankle: 20 deg DF. Noted by heel rise. 3rd rocker (forefoot). Decline in gastroc/soleus activity
-Knee: full extension for max step length
-Hip: 20 deg of hyperextension for max step length
CRITICAL EVENT: trailing limb
Swing limb advancement occurs at what phases of gait?
-Preswing
-Initial swing
-Mid swing
-Terminal swing
Preswing (50-60%)
-forefoot remains on ground
-knee rapidly flexes while weight shifted to other limb
-Ankle: 2nd arc of PF (15 deg), Toe rocker, No gastroc/soleus activity
-Knee: passive knee flexion 40 deg. Prepare limb for toe clearance
-Hip: 10 deg of hyperextension
-CRITICAL EVENT: Passive knee flexion 40 deg
Initial Swing (60-73%)
-Ankle: neutral
-Knee: Peak knee flex 60 deg for toe clearance. Peak mm activity of biceps femoris short head, gracilis, sartorius
-Hip: 15 deg of flex. Peak mm activity of gracilis/sartorius
CRITICAL EVENT: Peak knee flex at 60 deg and 15 deg of hip flex
Midswing (73-87%)
-Ankle: neutral to slight DF
-Knee: passive ext caused by momentum of hip flex
-Hip: Peak hip flex 25 deg
CRITICAL EVENT: Neutral to slight DF of ankle
Terminal swing (87-100%)
-leg reaches out to achieve step length
-prepare for IC
-Ankle: neutral to prepare for heel contact
-Knee: extension to neutral (5 deg flex). Extension controlled eccentrically by hamstrings. Quads turn on in late Swing to prepare for WB
-Hip: 20 deg flex
CRITICAL EVENT: extension to neutral of knee
Muscle Activity during Initial contact
-Ankle: pre-tib to counter PF moment
-Knee: quads for stability
-Hip: hamstrings/gluteals for stability
External moments:
-hip: flex
-knee: ext
-ankle: PF
Muscle Activity during Loading Response
-Ankle: pre-tibial to counter PF moment. Calf for stability
-Knee: quads to counter flex
-Hip: hamstrings/gluteals for stability
External moments:
-hip: flex
-knee: flex
-ankle: PF
Muscle activity during Midstance
-Ankle: calf for stability and counter DF moment
-Knee: quads for stance
-Hip: none
External moments:
-hip: ext
-knee: ext
-ankle: DF
Muscle activity during Terminal Stance
-Ankle: calf to counter DF moment
-Knee: none
-Hip: none
External moments:
-hip: ext
-knee: ext
-ankle: DF
Muscle activity during Pre-swing
-Ankle: calf to counter DF moment (early). Pre-tib for foot clearance (late)
-Knee: none
-Hip: Hip flexors to counter extension and intiate swing
External moments:
-hip: ext
-knee: flex
-ankle: DF
What key muscles control pelvic motion during gait?
hip extensors and abductors
What happens to the pelvis during gait in the sagittal plane?
-anterior pelvic tilt ~10 deg
-slight increase in anterior pelvic tilt during Tstance and Tswing
What happens to the pelvis during gait in the frontal plane?
-WA - 4 deg of contralateral pelvic drop
-Pswing - 4 deg of ipsilateral pelvic drop
What happens to the pelvis during gait in the transverse plane?
-pelvic protraction during Tswing and IC
-pelvic retraction during Stance
-neutral rotation and midswing and midstance
What is the average vertical and lateral displacement of the trunk during gait?
4.2 cm for vertical
4.5 cm R and L
What trunk extensors acts bilaterally during initial contact?
multifidus
Is shoulder flexion active or passive during contralateral initial contact?
passive shoulder movement (8 deg)
What muscles control shoulder extension during ipsilateral initial contact?
posterior deltoid and teres major
What are the critical joint angles and timing of gait cycle?
Ankle
-0 deg during swing
-20 deg DF during terminal stance
Knee
-60 deg flex peak during initial swing
-20 deg of flex during loading response
-0 deg of ext at initial contact and midstance
Hip
-25 deg peak flexion in midswing
-20 deg of extension in terminal stance
What are the critical muscle activity during gait cycle?
Ankle
-anterior tib eccentric during loading response
-anterior tib concentric during swing
-Gastroc eccentric during stance
Knee
-Quads active during stance to control knee flexion
-no hamstring or quad activity during midswing
Hip
-hip flexors concentric during swing
-hip abductors during SL support to prevent hip drop
Increased knee ADDUCTION moments have been associated with what diagnoses?
Knee OA
What are 5 methods of gait?
-manual assessment of spatial and temporal parameters
-instrumented walkways
-3-D gait analysis
-Video analysis
-Observational gait analysis
What is the main GOAL of gait methods?
Is the individual achieving a functional, comfortable, biomechanically efficient, and energy efficient gait
What should treatment intervention and outcome measurement tools be based on?
-objective
-reliable
-valid assessment
What outcome measures can be used for manual assessment of spatial and temporal parameters?
-Timed walk test (6MWT, 2MWT)
-10 meter walk test
-physical measurements of step length, width, or cadence
What are the advantages and disadvantages of instrumented walkways?
Advantages:
-easy to use
-less expensive
-portable
-requires minimal set up and space
-generally produce reliable data
Disadvantages:
-generally limited to temporal spatial data
-limited to number of steps
-artifical environment validity?
What does instrumented walkways measure?
-temporal spatial parameters
-foot contact patterns
What does 3-D gait analysis measure?
-temporal spatial parameters
-kinematics
-kinetics
What are the advantages and disadvantages of 3-D gait analysis?
Advantages
-captures joint kinematics and kientics in all planes
-accurate, good for complicated giat patterns
-can sync with EMG data
Disadvantages
-need large room
-costly
-must have knowledge to process data
-accuracy influenced by body composition and precision of marker placement
-skin artifact
GAITRite
-2ft wide x 12-24 ft length walkway
-numerous client-specific normal databases can be created and compared against
-can use to track a patient’s progress
Motion capture
capture rate: minimum 60 Hz, for walking for faster movements must increase rate
Detecting gait events
-foot strikes on force plates
-velocity of foot
-foot switches
Electromyograph (EMG)
Surface
-non-invasive
-good for group and/or surface muscle activity
-should be placed at muscle belly
-good for measuring timing of muscle activity
-signal can be “noisy)
-does not work well with thick layer of subcutaneous fat
Fine Wire
-invasive
-good for deep or specific muscle activity
-needles must be sterilized
-time sensitive
Plantar pressures
-instrumented insoles place in patient’s shoes
-can not use during barefoot walking
Inertial Measurment Units (IMU)
-self-contained system that measures linear and angular motion with the use of gyroscopes, magnetometers, and accelerometers
What are the advantages and disadvantages of video gait analysis?
Advantages:
-measures joint angles
-inexpensive
-simple to use
Disadvantages:
-accuracy
-patient conset to video
What are some tips for observational gait analysis?
-must be familiar with NORMAL gait
-start global then get specific
-breakdown into stance and swing and then further into phases
-can list in order of significance or superior <–> inferior
Abnormal joint ROM can cause gait deviations by
-joint contractures
-joint arthrodesis
-body malalignments
-compensatory postures
-ligamentous laxity
Pain or discomfort can cause gait deviations by
-injury
-disease
Impaired sensation can cause gait deviations by
-hyper- or hyposensitivity
-impaired propriocpetion
-CRPS
Impaired motor control can cause gait deviations by
Central
-weakness, hypertonicity, lack of selective control, apraxia, ataxia, rigidity
Peripheral
-disuse atrophy, muscle disease or injury, weakness
What are the 4 ankle rockers?
-1st rocker (heel): arc of ankle plantarflexion right after initial contact
-2nd rocker (ankle): tibial progression forward during midstance
-3rd rocker (forefoot): forefoot dorsiflexion as heel rises
-4th rocker (toe): tibia continues to progress forward as great toe extends
