Exam 1 Prep Flashcards
What are the two gait theories?
-Six determinants of gait
-Inverted pendulum
What is the Six determinants of gait theory?
-Follows kinematic theory which focuses on hip and knee motion
-Saunders et al hypothesized that the set of six major gait features were the important factors in reducing work expenditure during gait
-Sagital plane
-Hip and knee flexion
-Knee and ankle flexion
-Transverse/horizontal plane
-Pelvic rotation
-Frontal plane
-Lateral pelvic tilt
What is the 1st premise of the 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 is the 2nd premise of the six determinants of gait?
Minimizing the amount that the body’s center of gravity is displaced from the line of progression is the major mechanism for reducing the muscular effort of walking, and consequently, saving energy
What does the six determinants theory state?
That energy costs during gait is minimized by the six actions of the pelvis, hip, knee, and ankle
What is gait kinematics? What does it involve?
-Study of the motion of mechanical points of joints during upright mobility
-It involves
-Extent of joint movement (ROM)
-Speed
-Direction
What phases does the six determinants theory split the gait cycle into?
-Stance phase
-Swing phase
What percentage of the stance phase makes up the gait cycle?
60%
What percentage of the swing phase makes up the gait cycle?
40%
What does the inverted pendulum theory state?
-That 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 precribed by each single support phase. The limb travels like a pendulum, so it does not require much energy
What is the main propeller of gait?
The gastrocnemius during toe off/push off
What is the gait speed required to safely cross the street?
1.3 m/s
What are functional ambulatory terms for rehab?
-Safely cross the street
-Community ambulator
-Limited community ambulator
-Household ambulator
-Dependent ambulator (requires assistance of a person)
What can be predicted based on a gait speed greater than 1 m/s?
> 1.1 predictive of completing yard work
1.3 climb flights of stairs
What can be predicted based on a gait speed less than 1 m/s?
-Would benefit from fall prevention
> 0.67 able to complete self care
> 0.89 able to complete household activities
What can be predicted based on a gait speed less than 0.6 m/s?
-Predicts future risk of falls and hospitalization
-Tends to require assistance with ADL and IADL
≥ 0.49 able to cross street
What can be predicted based on a gait speed less than 0.4 m/s?
-Longer length of stay in acute care
-Likely to discharge to SNF, inpatient rehab, or nursing home setting
What is the stance phase of the gait cycle?
-During a walking cycle, a given foot is in contact with the ground
-From heel strike to toe off
What is the swing phase of the gait cycle?
During the walking cycle, a given foot is not in contact with the ground
What percent of the normal gait cycle is double support?
20-22%
When does double support occur in the gait cycle?
It occurs between the time one limb makes initial contact and the other one leaves the floor at toe off
What is the step length?
Calcaneus to contralateral foot calcaneus
What is the stride length?
-Calcaneus to ipsilateral calcaneus
-0.67 meters for women, 0.76 meters for men
-Should be twice the step length
What is one gait cycle?
Midpoint of calcaneus to midpoint of calcaneus
What are determinants of stride length?
-Age
-Height
-Gender
-Injury/illness
What are spatial parameters of gait?
-Step and stride length (should be equal bilaterally)
-Gait cycle
-Foot angle
What are temporal parameters of gait?
-Cadence (# of steps/minute)
-Swing or stance time
-Gait velocity
What gait measures do PT’s typically use in the clinic and what do we use them for?
-Gait velocity to determine discharge preferences and outcomes
-Stride length used for orthopedic injuries and neurological clients
-Level of community ambulation to determine safety
What is the calculation for gait velocity?
Cadence X stride length
What are the subphases of the stance phase?
-Initial contact
-Loading response
-Mid stance
-Terminal stance
-Pre swing
What are the subphases of the swing phase?
-Initial swing
-Mid swing
-Terminal swing
What are the tasks associated with the initial contact and loading response phases?
Weight acceptance
What are the tasks associated with the mid stance and terminal stance phases?
Single limb support
What are the tasks associated with the initial, mid, and terminal swing phases?
Single limb advancement
What is the definition of torque in regards to the gait cycle?
-Joint moment
-The amount of force that is required to stabilize or create movement in a joint axis
-Always looking at loaded position
-Exact measurement of joint moments
How is stance phase defined?
The point of initial contact to terminal stance
What are the normal ROM at the ankle knee and hip joint during initial contact?
-Ankle: 0 degrees
-Knee: 0-5 degrees
-Hip: 20 degrees of flexion
What are the normal ROM at the ankle, knee, and hip joint during loading response?
-Ankle: 5 degrees of plantar flexion
-Knee: 15 degrees flexion
-Hip: 20 degrees of flexion
At what point during the gait cycle is the highest amount of torque on the hip? What about the second highest?
-Initial contact
-Loading response (2nd)
What phases of the gait cycle is the heel rocker initiated?
-Initial contact
-Loading response
What are the normal ROM at the ankle knee and hip joint during midstance?
-Ankle: 5 degrees of plantar flexion in closed chain position
-Knee: 0-5 degrees
-Hip: neutral
What phase of the gait cycle is the ankle rocker initiated?
-Midstance
-Tibia moves over fixed foot
What are the normal ROM at the ankle, knee, and hip joint during terminal stance?
-Ankle: 10 degrees of dorsiflexion
-1st metatarsal: 30 degrees of extension
-Knee: 0-5 degrees
-Hip: 20 degrees of extension
What is the trailing limb?
-The leg that trails behind during terminal stance
-Allows for greater step length
-Key importance for clinical interventions
Why is the terminal stance phase so important for normal gait? What is the main muscle involved?
-This phase provides the force generation needed for forward propulsion
-Propulsion comes from the gastrocnemius and soleus muscles
What is the critical event in initial contact?
Heel contact with the ground
What are the critical events in the loading response?
-Hip stability
-Controlled knee stability
-Ankle plantar flexion
What is the critical event in midstance?
Controlled tibial advancement
What are the critical events in terminal stance?
-Controlled dorsiflexion w/ heel rise
-Force generation for propulsion
What are the normal ROM at the ankle, knee, and hip joint during mid-swing?
-Ankle: moves to neutral
-Knee: 25 degrees of flexion moving towards extension
-Hip: 25 degrees of flexion
What are the normal ROM at the ankle knee and hip joint during pre-swing?
-Ankle: 15 degrees of plantarflexion
-Metatarsals: 60 degrees of extension
-Knee: 40 degrees of flexion
-Hip: 10 degrees of extension
What are the critical events in initial-swing?
-15 degrees of hip flexion
-60 degrees of knee flexion
What are the critical events in pre-swing?
-Passive knee flexion to 40 degrees
-Ankle plantar flexion
What are the normal ROM at the ankle, knee, and hip joint during initial-swing?
-Ankle: 5 degrees of plantar flexion
-Knee: 60 degrees of flexion
-Hip: 15 degrees of flexion
What are the critical events in mid-swing?
-Hip flexion to 25 degrees
-Neutral ankle (0 degrees)
What is the critical event in terminal-swing?
Knee extension to neutral
What are the normal ROM at the ankle knee and hip joint during terminal swing?
-Ankle: dorsiflexion to neutral
-Knee: extends to neutral
-Hip: 20 degrees of flexion
What movements occur at the pelvis in the sagittal plane during the gait cycle?
-Pelvis already sits are 10 degrees of anterior pelvic tilt
-During walking anterior pelvic increases by 4 degrees during terminal stance
-In early single leg stance, a posterior pelvic tilt occurs
What movements occur at the pelvis in the frontal plane during the gait cycle?
During weight acceptance, the contralateral side of the pelvis drops 4 degrees
What movement occurs at the hip in the frontal plane during initial contact & loading response?
0-10 degrees of adduction
How long does it take for humans to get their gluteus medius strong enough for normal gait?
About 9-10 years
What will happen if someone walks in valgus at the knee joint for too long?
It will cause abnormal wear on the medial side of the knee, causing osteroarthritis
What movement occurs at the subtalar joint during loading response? What is the purpose of this movement?
-Pronation
-It unlocks the midtarsal joint to allow for shock absorption and reduces stress of loading response
-Tibia moves slightly into internal rotation
What movement occurs at the subtalar joint during terminal stance? What is the purpose of this movement?
-Eversion is reduced from 5 degrees to 2 degrees which allows the midtarsal joints to lock into place
-This provides a rigid forefoot while moving into supination to prepare for push off
What movements occur at the pelvis in the transverse plane during the gait cycle? How do these movements allow for optimal gait?
-Terminal stance phase: pelvis retracts 5 degrees
-Mid-swing: neutral
-Terminal swing: Pelvis rotates forward 5 degrees
-These movements allow for longer stride length
What movements occur in the trunk during the gait cycle? What movement does it coincide with?
-Thoracic rotation results in shoulder forward rotation, which creates the arm swing
-Thoracic rotation coincides w/ contralateral pelvis retraction
What is co-activation?
Simultaneous contraction of agonist and antagonist muscle groups to stabilize the joint
What occurs at the joint when co-activation should NOT be happening?
The joint does not move how it is supposed to and this can cause an abnormal gait pattern
What are muscular synergies?
When groups of muscles across joints work together to perform an activity
Why is walking/gait efficient and smooth?
-Muscular activity is delivered at the spinal cord level during gait
-Part of our genetic blueprint and years of training
-Finely tuned on and off muscular activation
How long does it take to fully develop gait?
6-10 years
What induces muscular on and off cycles? How does it induce them?
-Reciprocal inhibition
-It is governed at the spinal cord level
-System is created by a stimulus
-Occurs across muscles in both limbs
-Allows flexibility
-Governs motor function
What is an example of reciprocal inhibition during the gait cycle?
During the terminal swing phase, tibialis anterior turns on and gastroc/soleus turns off
What is an example of muscular co-activation during the gait cycle?
In terminal swing phase, quads are concentrically contracting and hamstrings are eccentrically contracting to control knee extension
Where are the central pattern generators (CPG’s) located? How do they help in gait?
-Located in the spinal cord
-Brain sends signals to spinal cord and CPG’s
-Spinal cord coordinates the on and off timing of motor activity during walking
-CPG’s control limb segments ipsilaterally and contralaterally
How is muscular activation organized in the gait cycle?
-Organized by swing phase (flexors) and stance phase (extensors)
-The timing of muscle groups is rhythmical and speeds up or slows down based on the individual’s pace
-Muscle activation pattern is similar across the human species
What phase of gait creates force generation?
Generation of force emerges from stance phase
What muscles are active at the hip, knee, and ankle during initial contact?
-Hip: glute max and adductor magnus
-Knee: quads
-Ankle: anterior tibialis eccentric
What muscles are active at the hip, knee, and ankle during loading response?
-Hip: glute max and adductor magnus, glute med
-Knee: quads eccentric
-Ankle: eccentric of TA, EHL, EDL
What muscle is activated late in the loading response?
Gastroc/soleus
What muscles are active at the hip, knee, and ankle during midstance?
-Hip: glute max, glute med, TFL
-Knee: quads
-Ankle: Soleus and gastroc eccentric control
What muscle helps provide shock absorption and helps the knee from buckling during the loading response?
Quads eccentrically contracting
What muscle controls the forward advancement of the tibia during mid stance?
Gastroc/soleus
What phase of gait are a lot of problems seen in?
Midstance
What is the main muscle that provides stability at the hip during loading response and midstance?
Glute med and TFL provide stability and help to keep the pelvis level
What muscles are active at the hip, knee, and ankle during terminal stance?
-Hip: TFL anterior fibers
-Knee: biceps femoris short head
-Ankle: Gastroc-soleus
What phase does gastroc/soleus muscle activation peak? Why does it peak at this phase?
-Terminal stance
-It peaks to prevent tibial collapse, which provides stability for propulsion
What needs to happen in order for proper push off to occur?
Trailing limb
What muscle provides the main forward propulsion for gait?
Gastroc/soleus
Which of the hip abductors stabilizes the hip for the longest amount of time during the gait cycle?
TFL
What muscles are active at the hip, knee, and ankle during pre-swing?
-Hip: adductor longus
-Knee: gracilis to prep for knee flexion
-Ankle: Gastroc/soleus ceases activity
What muscles are active at the hip, knee, and ankle during initial swing?
-Hip: iliacus, sartorius, gracilis
-Knee: biceps femoris, sartorius, gracilis
-Ankle: EDL, EHL, TA
What muscles are active at the hip, knee, and ankle during mid-swing?
-Hip: iliacus, gracilis
-Knee: Quads, hamstring eccentrically to control knee extension
-Ankle: TA
What is another name for the mid-swing phase?
Momentum phase
What muscles are active at the hip, knee, and ankle during terminal swing?
-Hip: hamstrings are at peak activity
-Knee: Quads
-Ankle: TA, EDL, EHL
What muscle group has the highest percentage of muscle force during initial contact?
-Hip extensors
-Knee flexors
What muscle group has the highest percentage of muscle force during the breaking phase/initial stance?
Hip abductors
What muscle group has the highest percentage of muscle force during terminal stance?
Ankle plantar flexors
What is a gait abnormality or deviation?
Any variation from the standard gait phases that involve the arms, trunk, pelvis, hip, knee, or ankle
What are etiologies that can cause gait deviations?
-Normal aging
-Pharmaceutical
-Disease
-Injury
What should always be performed in a clinical assessment?
An observational gait analysis
What is pelvic elevation in the gait cycle? What phase does it occur in?
Elevating the pelvis during swing phase, which provides a method to swing the limb forward if the person cannot do so properly
Why do some people have lateral leaning during gait?
-They have weak glute medius
-The lateral lean provides a way to offset some of the torque that is placed on the hip & glute medius
What is a common gait deviation in people with above knee amputations?
Hip hike and circumduction
What are some common trunk gait deviations?
-Lateral lean left/right
-Lateral lean back/forward
-Lateral rotation left/right
What are some common hip and pelvis gait deviations?
-Abductor lurch or glute medius gait
-Trendenlenburg gait
-Pelvic drop
-Waddling gait
What is ipsilateral pelvic drop caused by?
-Leg length discrepancy
-Short limb syndrome
What are some common hip gait deviations?
-Hip hike and circumduction
-Circumduction
What are some common knee gait deviations?
-Knee hyperextension (recervatum)
-Knee flexion during stance
-Knee varus
What are some common ankle gait deviations?
-Foot drop or high steppage gait
-Flat foot gait or calcaneal gait
-Vaulting
-Foot slap
-Heel off gait
What is vaulting? Why do people do it?
-Excessive plantar flexion during stance phase
-To avoid having to circumduct
What is heel off gait? Why does it normally occur?
-When someone doesn’t put their heel down when walking
-Toe walking
-Usually due to a hemiparesis
What are etiologies involved in foot drop? In what phase of gait is foot drop the most obvious/observable?
-Peripheral nerve injury
-Neuromuscular disease
-Observed throughout the entire swing phase
What does a physical therapist have to discern in pathologic gaits?
If it is:
-Skeletal system
-Muscular
-Neurologic
-Or whether it is pain that is causing
How do you determine if gait abnormalities are due to skeletal problems?
-Leg length discrepancy
-Limbs move in a predictable but abnormal pattern
-Observe standing alignment, ROM, and limb alignment assessments
What are some common skeletal gait abnormalities?
-Leg length discrepancy
-Foot progression angle (intoe and outtoe gait)
-Hip
-Knee
-Ankle
How much leg length discrepancy is too much?
More than 2 cm
What is a common cause of leg length discrepancy?
-Previous broken bone, especially as a child
-Bone infections
-Juvenile arthritis or athropathies
How do you measure leg length discrepancies?
-Hook lying
-Seeing if one leg goes out farther than the other (longer femur)
-Seeing if one knee is higher than the other (longer tibia)
-Supine, measuring from ASIS to medial malleolus
What is a normal foot progression angle?
-13-15 degrees external rotation
What population is in toe gait most common in?
-Common in children up to 4 years, but they should grow out of it
What are common causes of in toeing?
-Increased femoral anteversion
-Tibial torsion
-Club foot
What range of internal rotation should you suspect excessive femoral anteversion?
-More than 50 degrees
-Concerning if pt is over 16 years old
What are some exams to assess foot progression?
-Walking assessment
-Standing assessment
-Femoral anteversion
-Tibial torsion
-Foot or forefoot intoeing
How do you assess femoral anteversion?
-Prone w/ knees bent at 90 degrees
-Bring legs towards the table until the end of the ROM without lifting the pelvis at all
-If the angle is greater than 50, someone has excessive femoral anteversion
What can over pronation cause?
-Flat foot
-Internal rotation of tibia
-Calcaneus everts
-Unlocked midtarsal joint
-Midfoot pliability increases
-It can cause abnormal medial knee stress
-Reduces the efficiency during toe off
What are etiologies that cause neurologic gait deviations?
-CVA
-Stroke
-Hemiplegia
What is a common gait deviation with CVA?
-Ankle in plantar flexion
-Not in appropriate position for push off
