Determinants of Gait Flashcards
What is gait cycle?
Full completion of a single limb’s stance phase and swing phase
Stride Length?
Full gait cycle
Step length?
Length between one foot & opposite foot
Cadence?
Number if steps in a given amount of time
What can a wider step width mean?
Balance issues, peripheral neuropathy
What are some external forces creating torques?
Gravity & Ground reaction force
external forces = external moments
What generates internal forces to maintain equilibrium?
Muscle contractions
What is the equation for torque?
F*D
force * length of moment arm
What is torque?
the ability of any force to cause rotation about an axis
What is the GRF?
Ground reaction force
Equal in magnitude the force that the body applies to the floor through the foot
What are the 2 peaks in the GRF graph?
1st peak-period between initial contact and loading response
2nd peak- terminal stance and preswing phase
What are the external torque counterbalanced by?
Muscles (create internal torque)
What happens during single limb support?
Lateral shift of body mass, hip Abductors turn on to keep pelvis level and to maintain GRF
What can cause some anatomical mal-alignments of ?
Scoliosis, knee varus/valgus, increased rotation of hips, and posture
What kind of moments are created at the knee?
GRF force is just posterior to knee
Creates external flexion moment
What kind of internal moment is needed to counteract the posterior GRF at the knee?
Internal extension moment
Quadriceps turn on
In a hyperextended knee where is the GRF?
Anterior to the knee
With a hyperextended knee what kind of external moment is created, and what internal moment is needed to counteract it?
External extension moment
Internal flexion moment (Hamstrings, gastrocs, posterior knee capsule kick on)
What is the CoP?
Center of pressure-cumulative forces in a given area at an instance in time
Where is the CoP in the foot while walking?
- Initial contact - lateral to mid heal
2. Terminal stance - under medial forefoot
What are the 6 determinants of gait?
Pelvic rotation Lateral pelvic tilt Lateral shift Knee flexion Ankle DF Heel rise
Where does pelvic rotation occur?
Transverse Plane
What is the pelvic rotation during the swing phase?
Where swing side pelvis moves anteriorly to advance the leg forward. (ex. Left leg moving forward, left side of pelvis goes forward creating rotation to the right)
What is the pelvic rotation during the stance phase?
Pelvis moves opposite, (ex. standing on left leg, pelvis rotates back to left)
How is the lateral pelvic tilt controlled?
Gluteus Medius muscle (swing side pelvis drops)
What does the lateral pelvic tilt control?
Vertical excursion of the COM
swing hip falls lower
smooths pelvic trajectory
How far does the swing side pelvis drop during the swing phase?
1 inch
controlled
How far does the body shift laterally while walking?
1-2 inches toward stance leg
What can cause the lateral shift to increase or decrease?
Degrease: Knee valgus, feet are closer together
Increase: Wider stance, genu valgum
What is the stance knee flexion phase?
It’s when your knee flexes during weight acceptance
Where is the ankle DF important?
Early Stance/IC with heal
What does the heel rise when moving into the swing phase do?
Reduces the amount of extensor and flexor muscle activity needed.
What are the sagittal kinematics for the lower extremity?
Pelvis-Anterior/posterior tilt
Hip-In flexion at IC and move into extension as the body progresses
Knee-Knee flexion needed to minimize vertical translation
Ankle-PF/DF
How many degrees of DF do you need to have normal gait?
10 degrees
What are the frontal kinematics for the lower extremity?
Pelvis-Lateral tilt
Hip-moves with pelvis (with add until midstance, After midstance hip abd)
Knee-Minimal movement (slight varus during stance, valgus during preswing and initial swing)
Subtalar-Pronation/Supination
What are the transverse kinematics?
Pelvis-Axial rotation or (IR/ER)
Hip-IR/ER (slight ER at initial contact and move into IR in late midstance)
Knee-Tibia mirrors the femur
