Kinematic

Question 1

Why do impact sports require a higher sampling frequency?

Answer 1

Because they occur at a higher frequency so a higher frequency is needed to capture a true representation.

Question 2

Why do you need to use a high shutter speed?

Answer 2

Creates a clear image so joint marker locations can be pinpointed accurately

Question 3

What is genlocking?

Answer 3

Synchronisation of shutter speed across cameras - needed to 3D analysis

Question 4

What are the pros and cons of 2D analysis

Answer 4

Cheaper
Easier to use

Can only analyse one plane of motion at a time
Less accurate as always tends to be movement outside of one plane that can be important to whole movement

Question 5

What are the pros and cons and 3D motion analysis?

Answer 5

Truer representation of whole movement

More complicated and more expensive

Question 6

What are the main sources of error in movement analysis?

Answer 6

Human error - incorrect/inconsistent marker placement
Perspective error - objects distance from lens impacts its apparent size
Parallax error - false angles displayed unless perfectly perpendicular to lens

Question 7

What are some considerations when setting up a kinematic analysis?

Answer 7

Stable tripod
Camera positioned far away utilising zoom
High shutter speed
High frame rate (adequate to frequency of data)
Movement occurs perpendicular to camera
Tight clothes/reduce marker movement

Question 8

How would you ensure a reliable digitisation?

Answer 8

Repeat analysis of at least one recording several times and compare results - should be similar