forces applied to prosthetic and orthotic devices are _________
external forces
list the spatial descriptors of gait
- stride length
- step length
- degree of toe-out (foot angle)
- 5-7 degrees normal
- step width
- 8-10 cm average
_______ step length is often seen in amputees. Why?
asymmetrical
potentially due to spending less time in stance phase on involved side
results in shortening swing time and step length on noninvolved side
list the temporal descriptors of gait
- stride time
- step time
- cadence
- number of steps per minute (most important of these 3)
describe the spatio-temporal descriptor of gait that is the most important
gait speed
distance covered in a given amount of time
(step length * cadence)
(normal healthy is 1.37 m/sec)
T/F: it is common for prosthetic user to have reduced gait speed
TRUE
List some reasons for decreased gait speed in amputees
- new amputee might be afraid/decreased confidence → move slower and more cautious
- poor gait training
- pre amputation, the pt may not have had normal gait speed
what are the key features during IC/LR?
- Shock absorption
- PF
- knee flexion
- pronation
- hip adduction
- forward propulsion through hip extension
what are the key features of gait during midstance?
- shock absorption
- stabilize in single limb support
- forward progression of the tibia
- CK DF in able bodied gait
what are the key features of gait during terminal stance?
- continued stabilization in single limb support
- forward propulsion through PF
- forward progression
what are the key features of gait during pre-swing?
- continued forward propulsion through PF
- continued forward progression
what are the key features of gait during inital swing?
- forward propulsion of swing leg through hip flexion
- foot clearance
- DF
- knee flexion
what are the key features of gait during midswing?
forward propulsion of swing leg through hip flexion
what are the key features of gait during terminal swing?
- preparation for IC
- controlled knee extension
- ankle positioned into less supination
what key muscles are activated at the hip throughout gait and what are their roles?
- Hip extensors
- activated at TSw prior to IC to initate hip ext and prepare LE for weight acceptance at the beginning of stance
- Hip flexors
- advance LE forward during ISw and lift LE to allow for toe clearance during swing
- Hip abductors’
- control the slight lowering of the contralateral pelvis on the side of the swing limb
- Hip adductors
- assist w/initation of hip flexion after toe off
how does a TFA initate knee extension?
through hip extension
they will start to extend the hip as soon as the heel makes contact
this is why bench alignment promotes 5º hip flexion in order to make it easier for glutes to fire and extend the hip
what key muscles are activated at the knee and what are their roles in normal gait?
- knee extensors
- eccentrically control knee flexion in LR then act concentrically to extend knee and support body in MSt
- knee flexors
- decelerate knee extension in prep for placement of the foot on the ground
since amputee’s do not have ankle/pretibial muscles what occurs at the “ankle” during IC/LR?
foot slap
if the heel bumper or prosthetic foot is either too soft or firm, you may observe a delay or an acceleration of that foot flat process
how does the loss of PF due to amputation or weakness impact gait?
- shorter contralateral step length
- reduced gait speed
- impaired balance
*most noticable in MSt where gastroc is normally most active
how is knee flexion achieved in amputees?
no mechanism is needed if:
- the individual can flex their hip
- ambulate fast enough to produce momentum
what is the assocation between amputation level and energy consumption during gait?
as the level of the amputation moves more proximal, the energy efficiency and biomechanical efficiency decreases
T/F: dysvascular amputees tend to have faster gait speeds than traumatic amputees?
FALSE
traumatic amputees tends to be more efficient and don’t see as large of a decrease in walking speed, stride length, and cadence
what are the general goals we want to reach with TTA gait?
**gait that is as close to normal as possible
key alignment issue is the socket/foot relationship
want to observe them effectively shifting weight over the prosthetic limb during PSw by looking at their pelvic, trunk, and head position
what is the difference between pistoning and bell-clapping?
pistoning → movement that occurs up/down as the residuum moves away from the socket due to a poor fit
bell-clapping → movement that occurs anterior/poosterior due to poor fit
