Lecture 23

Question 1

Center of mass in walking

What model is used

Answer 1

Midstance = highest COM position

Inverted pendulum model

Question 2

Where is the COM potential energy highest

Answer 2

Walking Midstance

Question 3

Where is the COM kinetic energy lowest

Answer 3

Walking Midstance

And

Running Midstance????

Question 4

COM of PE and KE are… (walking)

Answer 4

Out of phase

Question 5

Center of mass in running

What model is used

Answer 5

Midstance = lowest COM position

Spring mass model

Question 6

Where is the COM potential energy lowest

Answer 6

Running Midstance

Question 7

COM PE and KE are…. (running)

Answer 7

In phase

Question 8

What are the functions of foot ankle complex

Answer 8

Provides base of support to maintain balance

Serves as an energy source and energy sink, is involved with energy exchanges

Question 9

In walking there is a….

Answer 9

Positive mechanical work generation

Question 10

In running there is a…

Answer 10

Positive mechanical work generation

Question 11

Structure of the foot:

Forefoot

Midfoot

Hindfoot

Answer 11

Forefoot = metatarsals, Phalanges

Midfoot = navicular, cuboid, three cuneiform

Hindfoot = talus, calcaneus

Question 12

What are the metatarsal phalangeal joint function

Answer 12

Supports the body

Provide traction

Control the forward motion of the COM during propulsion

Question 13

What are the two most common injuries to the foot and ankle

Answer 13

Stress fractures of metatarsals

Inversion ankle sprains

Question 14

Stress fractures occur as a result of

Answer 14

Microtrauma to bone

Question 15

What are the causes of stress fractures

Answer 15

Uncontrolled foot landing

Hard landing on the ground

Improper spring of the foot action

Question 16

What is a foot spring responsible for

Answer 16

Transferring forces from achilles tendon to forefoot

Question 17

What will happen if there is a decrease in tension in the spring

Answer 17

Increase strain on the metatarsals

Question 18

In the terminal stance phase (push off), a decrease in tension in spring will…

Answer 18

Shift GRF and contact area from toes to metatarsals

Question 19

Inversion of the ankle is when the

Eversion of the ankle is when the

Answer 19

Foot turns inwards

Foot turns outwards

Question 20

Why are inversion sprains more common than eversion sprains

Answer 20

Longer lateral malleolus

Stronger deltoid ligaments

Question 21

Tibiofemoral joint is made up of

Answer 21

Tibia and femur

Question 22

What two rotational degree of freedom (DOF) are there in the Knee complex

Answer 22

Flexion/extension

Internal/external rotation

Question 23

The patellofemoral joint is made up of

Answer 23

The femur and patella

Question 24

What common knee injuries are there

Answer 24

Ligamentous sprains

Meniscal tears

Osteoarthritis

Question 25

Anterior cruciate ligament attaches to

What causes tension to develop in the ACL

Answer 25

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

Question 26

Potential cuases of ACL injury

Answer 26

Suddenly sloowing down and changing direction (cutting)

Landing awkwardly from a jump

Stopping suddenly

Recieving a direct blow to knee

Question 27

What is the key component cause of Patellofemoral pain syndrome

Answer 27

Stress

Question 28

What are the other causes of patellofemoral pain syndrome

Answer 28

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)