The Gait Cycle- Kinetics Flashcards
What is the butterfly diagram?
It shows GRF through the stance phase
Describe the GRF during early stance
- Acts upwards and diagonally backwards from the heel
- Exerts a braking or slowing effect on forward moment
Describe the GRF during middle of stance phase
- Point of action moves forward from heel
- line of action becomes more vertical and braking/slowing effect disappears
Describe GRF at the end of stance phase
- GRF increases in magnitude, acting forwards and upwards
- gives necessary propulsive force to keep the body moving forwards
Describe GRF at the end of stance phase
- GRF increases in magnitude, acting forwards and upwards
- gives necessary propulsive force to keep the body moving forwards
When is the GRF lowest?
Midstance
If the GRV is behind the ankle, what muscles are active?
DF (Tibialis Anterior)
If the GRV is posterior to the knee, what muscles are active?
Quads
If GRV is anterior to the ankle, what muscles are active?
Gastroc and Soleus
If GRV is anterior to the knee, what creates the internal flexor moment?
Posterior capsule ligaments instead of hamstrings
What does an increase in lever arm of GRV at the ankle mean?
PF are increasingly active
Describe TD and MA at the ankle during IC.
TD: Plantar flexion torque
MA: pretibial muscles maintain neutral ankle for heel rocker action
Describe TD and MA at the knee during IC.
TD: GRV is anterior to the knee, creating an extension torque.
MA: Quads contract, hamstrings prevent hyperextension
Describe TD and MA at the hip during IC.
TD: GRV anterior to hip joint so flexion torque.
MA: Hip extensors (GMax and Hamstrings) are active to stabilize the thigh during loading and to begin extension.
Describe TD and MA at ankle during LR.
TD: GRV posterior to ankle, so PF torque.
MA: Tib A contracts eccentrically
Describe TD and MA at knee during LR.
TD: GRF now behind the knee, so flexion torque
MA: Hamstring concentrically contracting and quads eccentrically contracting.
Describe TD and MA at hip during LR.
TD: GRF anterior to hip, flexion torque.
MA: GMax and Hamstrings contract concentrically to extend hip.
Describe TD and MA at ankle during Opposite Toe Off
TD: GRF moves forward, DF moment.
MA: Triceps surae eccentrically contracts to control DF as body and tibia move forward.
Describe TD and MA at knee during Opposite Toe Off
TD: GRF is behind the knee, so flexion torque at the knee.
MA: quads are eccentrically controlling knee flexion
Describe TD and MA at ankle during Opposite Toe Off
TD: GRF moves forward, DF moment.
MA: Triceps surae eccentrically contracts to control DF as body and tibia move forward.
Describe TD and MA at knee during Opposite Toe Off
TD: GRF is behind the knee, so flexion torque at the knee.
MA: quads are eccentrically controlling knee flexion
Describe TD and MA at hip during Opposite Toe Off
TD: GRF close to joint
MA: GMax and Hamstrings contract concentrically to extend hip
Describe TD and MA at ankle during Mid-Stance.
TD: GRF forward, so DF moment.
MA: Triceps surae contracts eccentrically to control DF
Describe TD and MA at knee during Mid-Stance.
TD: GRF behind joint, creating flexion torque.
MA: Quads contract concentrically to extend knee.
Describe TD and MA at hip during Mid-Stance.
TD: GRF through joint line
MA: Hip extends due to inertia and gravity. Stance limb ABD eccentrically control a slight dip on the swing limb side
Describe TD and MA at ankle during Heel-Rise.
TD: GRF still anterior, so external DF moment.
MA: Triceps surae reach eccentric contraction peak (Ankle DF reaches peak)
Describe the position of the tibia and foot during Heel Rise
- Tibia is externally rotated
- Foot is supinated
Describe TD and MA at knee during Heel-Rise.
TD: GRF moves anterior to knee jt, so extension torque.
MA: Knee reaches extension peak, Gastrocs contract to prevent hyperextension and initiate knee flexion.
Describe TD and MA at hip during Heel-Rise.
TD: GRF behind jt, small extension moment
MA: No significant muscle activity at hip.
Describe TD and MA at ankle during Opposite IC.
TD: GRF passes through forefoot, significant DF moment.
MA: triceps surae contract concentrically to generate a large internal PF moment. Highest power generating moment in gait cycle
Describe the activity of the toes and feet during Opposite IC.
- Toes extend, plantar facia tightens
- Foot supinated (more rigid)
Describe TD and MA at knee during Opposite IC.
TD: GRF behind knee, so knee flexion moment.
MA: Quads, may contract eccentrically to prevent knee flexion from occurring too rapidly
Describe TD and MA at knee during Opposite IC.
TD: GRF behind knee, so knee flexion moment.
MA: Quads, may contract eccentrically to prevent knee flexion from occurring too rapidly
Describe TD and MA at hip during Opposite IC.
TD: GRF in front of jt, creating a flexion torque.
MA: Combination of stretched ligaments, gravity, adductor longus reverse the direction from hip extension to flexion.
Describe TD and MA at ankle during Toe Off
TD: magnitude of GRF declines with external DF moment.
MA: Triceps surae activity ceases, Tib A contracts to DF ankle to neutral.
Describe TD and MA at knee during Toe Off
TD: GRF behind the knee, so external flexion moment.
MA: Knee flexion results mostly from hip flexion and inertia. Rectus femoris may contract eccentrically to prevent excessive knee flexion.
Describe TD and MA at knee during Toe Off
TD: GRF behind the knee, so external flexion moment.
MA: Knee flexion results mostly from hip flexion and inertia. Rectus femoris may contract eccentrically to prevent excessive knee flexion.
Describe TD and MA at hip during Toe Off
TD: negligible
MA: Illiopsoas, Rectus Femoris, and adductor longus contract to flex hip and pull LE forward.
What muscle is the prime mover for hip flexion during InSw?
Iliopsoas
How is flexion decelerated in TSw?
With the use of hamstrings
When are the quads activated during swing phase?
Quads contract to ensure full extension in terminal swing.
What is the job of hamstrings during TSw?
Eccentrically control terminal extension
What is the job of the Tib A during swing phase?
isometrically maintains the ankle in neutral.
What is the job of the Tib A during swing phase?
isometrically maintains the ankle in neutral.
What is the job of the Tib A during swing phase?
isometrically maintains the ankle in neutral.
what phase of the gait cycle is Glut Max active and which phase is it most active?
LR* and TSw
what phase of the gait cycle is Glut Med, Min, and TFL active and which phases are they most active in?
LR, MSt, TSt
what phase of the gait cycle is Iliopsoas active and which phases are they most active in?
PSw and ISw
what phase of the gait cycle is Hamstrings active and which phases are they most active in?
TSw*, LR
what phase of the gait cycle is Quadriceps active and which phases are they most active in?
LR*, MSt, TSw, PSw, ISw
what phase of the gait cycle is Rectus Femoris active and which phases are they most active in?
PSw, ISw
what phase of the gait cycle is Triceps Surae active and which phases are they most active in?
MSt, TSt
what phase of the gait cycle is Triceps Surae active and which phases are they most active in?
MSt, TSt*
what phase of the gait cycle are the DFs active and which phases are they most active in?
LR, ISw, MSw, TSw
