Gait Flashcards
what is walking?
walking is a method of locomotion
involving the use of two legs,
alternatively, to provide both
support and propulsion with at least
one foot on the ground at all times
What is gait?
describes the manner or style of walking rather than the walking process itself
What is the gait cycle?
starts with the right foot heel strike, followed by a brief period of double support, followed by a period where the left foot is off the ground (swinging).
The left swing phase finished with the left foot
contact and a second period of double support, followed by a right leg swing phase
Describe the timing of the gait cycle
The precise duration of the gait cycle intervals varies with the person’s walking velocity.
At customary 80m/min rate of walking, stance and swing periods represent 62% and 38% of the gait cycle respectively.
Walking faster lengthens single stance and shortens the two double stance intervals
What are the gait parameters?
Stride length, step length, walking base (step width and toe out angle
Describe phase 1 and 2 of gait: initial contact and loading response
Initial contact: Interval: 0-2% GC
Moment when foot touches the floor. The joint positions at this time determine the limb-loading response pattern.
Obective: Position limb 2 start stance with
heel rocker
Loading response: Interval: 0-10% GC
Initial double stance period. Phase begins with initial floor contact and continues until
other foot is lifted.
Objective: Shock absorption, Weight bearing stability, Preservation of progress
Describe phase 3 and 4 of gait: Mid stance and terminal stance
Mid-stance: Interval: 10-30% GC
First half of single limb support. Begins
as the other foot is lifted and continues
until body weight is aligned over the
forefoot.
Objective: Progression over the stationary foot and Stability
Terminal-stance: Interval: 30-50% GC
This phase completes single limb support. Begins with heel rise and continues until other foot strikes the ground.
Describe phase 5 and 6 of gait: Pre-swing and Initial Swing
Pre-swing: Interval: 50-60% GC
Second double stance interval. Begins
with initial contact of the opposite limb
and ends with toe-off. Sometimes
referred to as weight transfer.
Objective: Position the leg for swing
Initial Swing: Interval: 60-73% GC
Begins with lift of foot from the floor and ends when the swinging foot is opposite the stance foot.
Objective: Foot clearance from floor and Advancement of limbs from the trailing position.
Describe phase 7 and 8 of gait: Mid-swing and terminal swing
Mid-swing: Interval: 73-87% GC
Second phase of swing period begins as the swinging limb is opposite the stance limb. Phase ends when the swinging limb is forward and the tibia is vertical.
Objective: Limb advancement and foot clearance from floor
Terminal Swing: Interval: 87-100% GC
Begins with a vertical tibia and ends
when the foot strikes the floor. Limb
advancement is completed as the leg
moves ahead of the thigh
Objecitve: Complete limb advancement and prepare the limbs for stance
Describe the stability function of locomotion
Stability: beginning of stance, foot is ahead of trunk, and body vector is anterior
to hip and posterior to knee. Flexion torque created at both joints, needing an active extensor muscle response to restrain the body.
During mid-stance, the body advances to a position over the supporting foot. This reduces
the flexion torques to zero.
As the body weight moves ahead of the ankle, a new area of postural instability is
introduced. Active control by the planar flexor muscles is needed to restrain the forward
fall of body weight.
Both feet in contact with ground trunk is supported. balance lost during swing
Describe the progression function of locomotion
momentum of forward fall preserved by heel rocker. Action of pretibital muscles draws the leg forward. quad musles act to tie tibia to femur. heel rocker facilitates profression of entire stance limb.
Ankle rocker: ankle as fulcrum, tibia rolls forward in response to momentum - rate of tibial progression decelerated by soleus muscle
Forefoot rocker: tiibial progression continued over forefoot rocker, Both gastrocnemius and soleus delecrate rate of tibial advancement
Describe shock absorption function of locomotion
end of single support - body weight ahead of area of forefoot support = unblanaces with body falling forward = abrupt loading of forward limb.
shock absoring reaction = free ankle plantar flexion following heel contact before pretibialmuscle restrain motion and reduce rate at which falling body weight is transferred.
Knee flexion is the second and greater shock absorber. Pretibial muscles tie leg to foot = tibia move forward and knee flexes. action of quad to decelerate rate of knee flexion transfers some of the loading forces to muscles.
loading of one limb unloads other = removes support causing pelvic drop
rate of pelvic drop restrained by abductor muscles
impact of limb loading absorbed by muscular action
describe the energy conservation function of locomotion
preservation of stance stability by selectively
restraining falling body weight and advancing the swinging limb as the body progresses constitutes the work being performed
least energy would be used if weight carried remained at constant height (potentially diff in hip height = 9.5 cm
vertical lift minimised: tilting of pelvis & flexion of knee and ankle
Lowering of body minimized: heel rise, full knee extension and rotation of pelvis.
less energy expanded by subbing passive control and available momentum for muscle action. timing and intensity of muscular action modulated. at knee peak, quad action only occurs during loading response and onset of mid stance - vector moves forward of knee axis, muscle relax, and momentum completes extensor motion
