GRF, Moments and Pathological Gait Flashcards
(33 cards)
What are the Internal joint moments in the Ankle, Knee and Hip during the loading response?
Ankle - DF Moment
Knee - Flexor moment
Hip - Extensor Moment
What is the Internal joint moment in the ankle during midstance?
Plantarflexion to control the rate of the dorsiflexion
Position of the GRF at ankle during the loading phase?
Behind the ankle joint
What is the internal joint moment at the ankle during terminal stance
Plantarflexion moment
What is the GRF Vector at ankle in terminal stance AND what moment/contraction/muscles are active?
- GRF vector is infront of the ankle joint
- Anterior GRF causes a high plantarflexion moment
- Causing a concentric contraction of the triceps surae (power generation) before preswing
What is the joint moment at the ankle during the pre-swing phase?
Plantarflexion moment
- Power generation phase declines (as the foot is nearly off the ground)
What happens at the ankle during initial swing?
- Ankle rapidly dorsiflexes
- TA contracts concentrically to cause the motion
- Small amounts of moments are occuring as the only weight is the weight of the foot.
What Happens at the knee at HS?
(Moments, What type of contraction? What muscles area active?)
There is a knee flexor moment
Hamstrings contract to prevent hyperextension of the knee (braking mechanism)
What Happens at the knee during the loading phase?
(Moments, What type of contraction? What muscles are active?)
GRF lies behind the knee
Internal Extensor Moment
(Eccentric contraction of the Quads –> absorb the power and speed of the knee flexion)
GRF at knee in terminal stance & Muscle Activity
Behind the knee (aiding the flexion)
Rectus Femoris eccentric contraction (prevent excessive flexion)
What is the double pendulum mechanism?
During the Preswing phase, the knee flexes as a result of hip flexion
Shank is left behind due to inertia causing knee flexion to occur
What Internal Joint Moment occurs at the knee during Terminal Swing?
(Generated by what muscle group)
Knee Flexor Moment
Generated by the hamstrings (power absorbtion phase) preventing rapid knee extension and hyperextension before the second heel strike
What moment occurs at the hip during the loading phase? (Generated by what muscle group?)
Hip Extensor moment
Generated by the hip extensors
What Moment Occurs at the hip during mid stance?
(Generated by what?)
Hip Extensor Moment
Generated by the extensor moment (power generation) as the body moves over the fixed limb
(Think of the GRF is Behind the Hip Joint)
Causes of Step Length Asymmetry
Weak Push off
Weak Hip Flexor Activity in early swing
Hyperactive hamstrings in late swing
Result of Loss of dorsiflexion function during Gait
- Foot Slap
- Increased loading time under the heel
- Decreased loading under the hallux
What is a common sign of individual with cerebral palsy at Initial Contact?
Knee flexion –> Due to contracture of hamstrings or muscle spasticity
What causes excessive knee extension during stance phase?
Weak Knee Extensors
Knee pain
- if an individual has pain, locking the knee would result in a stiff joint and limit the pain associated with walking
What is Jump Knee?
Knee flexed at initial contact but extends during the stance
What is vaulting?
A compensation for decreased foot clearance on the contralateral side.
Patient goes up on their toes on the non affected leg, to improve toe clearance of the swinging leg (affected leg)
What can cause a decrease in stride length / Gait speed?
Weak Pushoff
What is Circumduction?
When the swinging leg is swung outwards during the swing phase
Resulting in advancing the swinging leg in the presence of weak hip flexors
Name the pathology:
Pelvis lifted on the side of the swinging leg, by contraction of the spinal muscles and lateral abdominal wall
Hip Hiking
What is Steppage (Steppage Gait)
Exaggerated knee and hip flexion during the swing phase to lift the foot higher than usual for increased ground clearance.
Used for compensation of lack of dorsiflexion control
