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