W33 - Internal Loading

Question 1

What 3 bits of information do you need to calculate Internal Force?

Answer 1

Kinematic Data
Inertia Data (mass, CoM etc.)
External Force Data

Question 2

What does Inverse Dynamics Analysis allow us to calculate?

Answer 2

Internal joint moments
Muscle moments
Muscle Power

Question 3

What are some practical applications of calculating internal loading?

Answer 3

Injury prevention and rehab
Can see whether joints are working in the right way
Can see how efficient somebodies movement is

Question 4

What is NL2? (equation)

Answer 4

Sum of Force = Mass x Acceleration

Question 5

What is the angular equivalent of NL2? (equation)

Answer 5

Sum of Torque or Moments = Moment of Inertia x Angular Acceleration

Question 6

What is a free body diagram?

Answer 6

A model of a segment with all forces and moments acting on it
Stick figure diagram

Question 7

What direction is positive for moments?

Answer 7

Anticlockwise, up, right

Question 8

What are some limitations for Inverse Dynamics Analysis?

Answer 8

Assumes rigid segments
Propagation of error (any error is carried over and gets bigger in next calc)
Doesn’t look at what causes turning forces (antagonistic muscle pairs)
Sensitive to kinematic data

Question 9

What is Inverse Dynamics Analysis?

Answer 9

Measured kinematics and external forces are used to calculate net joint moments in a rigid body linked segment model