Lecture 23 Flashcards
Center of mass in walking
What model is used
Midstance = highest COM position
Inverted pendulum model
Where is the COM potential energy highest
Walking Midstance
Where is the COM kinetic energy lowest
Walking Midstance
And
Running Midstance????
COM of PE and KE are… (walking)
Out of phase
Center of mass in running
What model is used
Midstance = lowest COM position
Spring mass model
Where is the COM potential energy lowest
Running Midstance
COM PE and KE are…. (running)
In phase
What are the functions of foot ankle complex
Provides base of support to maintain balance
Serves as an energy source and energy sink, is involved with energy exchanges
In walking there is a….
Positive mechanical work generation
In running there is a…
Positive mechanical work generation
Structure of the foot:
Forefoot
Midfoot
Hindfoot
Forefoot = metatarsals, Phalanges
Midfoot = navicular, cuboid, three cuneiform
Hindfoot = talus, calcaneus
What are the metatarsal phalangeal joint function
Supports the body
Provide traction
Control the forward motion of the COM during propulsion
What are the two most common injuries to the foot and ankle
Stress fractures of metatarsals
Inversion ankle sprains
Stress fractures occur as a result of
Microtrauma to bone
What are the causes of stress fractures
Uncontrolled foot landing
Hard landing on the ground
Improper spring of the foot action
What is a foot spring responsible for
Transferring forces from achilles tendon to forefoot
What will happen if there is a decrease in tension in the spring
Increase strain on the metatarsals
In the terminal stance phase (push off), a decrease in tension in spring will…
Shift GRF and contact area from toes to metatarsals
Inversion of the ankle is when the
Eversion of the ankle is when the
Foot turns inwards
Foot turns outwards
Why are inversion sprains more common than eversion sprains
Longer lateral malleolus
Stronger deltoid ligaments
Tibiofemoral joint is made up of
Tibia and femur
What two rotational degree of freedom (DOF) are there in the Knee complex
Flexion/extension
Internal/external rotation
The patellofemoral joint is made up of
The femur and patella
What common knee injuries are there
Ligamentous sprains
Meniscal tears
Osteoarthritis
Anterior cruciate ligament attaches to
What causes tension to develop in the ACL
The posterior part of the distal femur and anterior part of the proximal tibia
If tibia moves anterior or knee internally rotate, tension will develop in ACL
Potential cuases of ACL injury
Suddenly sloowing down and changing direction (cutting)
Landing awkwardly from a jump
Stopping suddenly
Recieving a direct blow to knee
What is the key component cause of Patellofemoral pain syndrome
Stress
What are the other causes of patellofemoral pain syndrome
Patellofemoral joint reaction force (too high)
Contact area between patella and femur (too small)
Changes based on knee angle (contact area increases as knee flexion angle increases)
