Gait Flashcards
Gait cycle
Ipsilateral heel contact to next ipsilateral heel contact, one stride
Cadence
Walking speed (norm. 110/min)
Eccentric Contraction
Muscle lengthening under load
Power absorbed by the muscle
Concentric Contraction
Muscle shortening under load
Power is generated by the muscle
Functional Elements of Gait
Progression
Standing/walking stablity
Locomotor Unit
Passenger Unit
Energy Conservation
Maximized by attenuating CoG linear translation and substituting momentum for muscle action
Stance Phase
Period from initial contact of foot to the ground until that foot leaves the ground
Average 60% of the gait cycle
Includes Heel strike Loading response Midstance Push off
Swing Phase
Period from when foot leaves the ground until that foot contacts the ground again
Average 40% of the gait cycle
Initial Swing - acceleration of limb forward
Mid-Swing - limb under CoG and flexed for toe clearance
Terminal Swing- deceleration of forward limb motion
Double Support
Period from initial contact from one side until the foot on the other side leaves the ground
Occurs twice- first and last 10% of the gait cycle
Double support time is directly and inversely proportional to cadence, as cadence increases, double support time decreases
Location of GRF/TBF relative to joints at heel strike, function
Ahead of hip
Behind knee
Behind ankle
Shock absorption, attenuation and deceleration of CoG. Hip extensors act to stabilize the HAT during acceleration
Muscle action at heel strike
Hip - isometric contraction of extensor group (G. max, Hams)
Knee - eccentric contraction of extensor group (quads)
Ankle - eccentric contraction of dorsiflexors (tibialis anterior)
Location of GRF/TBF relative to joints at foot flat, function
Ahead of hip
Behind knee
Through ankle
Shock absorption, attenuation, and deceleration of CoG
Muscle action at foot flat
Hip - concentric contraction of extensor group (Gluteus Max, Hamstrings)
Knee - eccentric contraction of extensor group (Quads)
Ankle - muscle groups and moments switch to plantarflexors
Location of GRF/TBF relative to joints at midstance, function
Through Hip (sagittal), lateral to hip (frontal)
Behind knee (sagittal)
Ahead of ankle (sagittal)
Attenuation of CoG displacement
Muscle action at midstance
Hip - eccentric then concentric contraction of hip abductors (gluteus medius)
Knee- concentric contraction of extensor group (Quads), gradually replaced by Triceps Surae
Ankle - eccentric contraction of plantar flexors (tricpes surae)
Location of GRF/TBF relative to joints at Push Off, Function
Behind the hip
Ahead of the knee
Ahead of the ankle
Function
Forward propulsion and acceleration of CoG
Hip stabilizes HAT during acceleration
Muscle action at push-off
Hip - concentric contraction by the hip flexors
Knee - maximum extension at heel off, then begins flexing, concentric contraction
Ankle - concentric contraction of triceps surae
Location of GRF/TBF relative to joints at Swing phase, Function
Not touching ground, therefore no GRF/TBF line
Function - Ensure adequate toe clearance, propel swing limb forward, ready the limb for weight acceptance
Muscle action at swing of hip
Hip
Early swing - concentric contraction of hip flexors accelerating limb forward
Late swing - eccentric contraction decelerates it by using the hip flexors (illiopsoas) and the hip extensors (g.max, hams) respectively
Muscle action at swing of knee
Knee
Early swing - eccentric contraction of knee extensors prevents excessive heel rise
Late swing - eccentric contraction of flexor group (Hams) assists in decelerating swing limb
Muscle action at swing of ankle
Ankle
Early swing- concentric contraction of dorsiflexors ensures toe clearance
Late swing- isometric contraction as limb readies itself for weight acceptance
Functions of Orthoses
i) Stabilize
ii) Correct/Prevent/Support Deformity
iii) Exercise
iv) Control or Limit Joint ROM
v) Transmission of Motor Functions
vi) Compensate for Deformity
vii) Reduction of Heat Loss
Heel Rocker refers to what phases of gait
Loading Response to Midstance
Ankle Rocker refers to what phases of gait
Midstance to Terminal Stance
Forefoot Rocker refers to what phases of gait
Terminal Stance to Preswing