gait Flashcards
functional gait tasks
stability
propulsion
efficiency
bipedal gait advantages
frees hands, elevates head
travel on irregular surfaces and over obstacles, change of direction
energy efficient
bipedal gait disadvantages
difficult to sustain COM in straight line
COM is an arc shaped pattern with lateral sway
maintaining a smoother trajectory of the CM
vulnerable to disease
stability of gait
against gravitational and inertial forces
propulsion of gait
adding energy to the system
efficiency of gait
minimizing changes in kinetic energy (shock absorption)
minimizing changes in PE
cycle / stride
single sequence of one foot, heel to heel
step lenght
heel to heel of opposite feet
stride length
double step length = cycle or stride length
walking base
distance to the midline of the two feet
cadence
steps per unit time avg = 110 steps/min
midline
line through the center point of both feet
stance phase
60% of gait cycle
initial contact
early stance
mid stance
terminal stance
swing phase
40% of gait
initial swing
mid swing
late swing
3 functional tasks of gait
weight acceptance
single limb support
limb advancement
weight acceptance
initial contact & loading response
- requires initial limb stability and shock absorption while simultaneously preserving the momentum of progressions
- if successful individual demonstrates stable kinetic chain
single limb support
Mid stance & terminal stance & preswing
- forward progression of body weight over stationary foot while maintaining stability
limb advancement
pre swing, initial swing, mid swing and terminal swing
- stance limb leaves ground and advances forward to posture itself in prep for next initial contact
- if successful individual demonstrates open kinetic chain
initial contact
instant foot touches ground
0-2%
loading response
BW is fully transferred onto the stance limb
0-10%
midstance
starts when contralateral foot leaves ground and continues as BW travels until its aligned over the forefoot
10-30%
terminal stance
starts w heel rise and ends when the contralateral foot contacts ground
BW moves ahead of forefoot
30-50%
preswing
starts when contralateral foot contacts ground
stance limb is unloaded and BW is transferred to contralateral limb
50-62%
initial swing
instant foot leaves ground and continues until max knee flexion
62-75%
midswing
following max knee flexion, ends when tibia is vertical 75-85%
when walking speed increase
stance phase decreases
swing phase increases
double support decreases
running
walking with no double support
ratio stance/swing reverses
determinants of gait
- pelvic rotation
- pelvic tilt
- knee flexion in stance phase
- ankle mechanism
- foot mechanism
- lateral displacement of body
Trendelenburg gait
failure of hip abductors to produce a sufficient abductor moment during loading response and terminal stance
lateral lurch
abductor weaknesses or coxofemoral pain
excessive lateral displacement of the trunk toward the affected side
antalgic gait
stance phase is shortened to relative swing phase (pain with weight bearing)
lateral trunk bending
significatn leaning of the trunk toward the prosthetic side at midstance
increased walking base
a wide walking base may increase stability but at a sacrifice for efficiency
inadequate dorsifelxion control
achieve ground clearance during swing phase
dorsiflexors resist the external plantar flexion moment
gait control
- activation of gait command in the central NS
- transmission of the gait signals to the peripheral NS
- contraction of muscles that develop tension
- generation of forces at and moments across synovial joints
- regulation of the joint forces and moments by the rigid skeletal segments
- displacement of the segment
- generation of GRF
joint power is the ….
product of joint angular velocity and the corresponding internal moment at a given point in time
What is the objective of the six determinants of
Gait?
-Minimize excursion of COM in vertical and horizontal planes
-Reduce energy consumption of ambulation
