W30 - Principles of Biomechanic Models

Question 1

What is Visual 3D used for?

Answer 1

Modelling tool that can define rigid segments and link them together
Can measure any kinematic variable you want
Takes each segment as an LCS and compares where it is in relation to the GCS

Question 2

What is a body segment?

Answer 2

A rigid body
Any area between two joints
E.g. foot, shank, forearm, hand

Question 3

What are the different types of markers?

Answer 3

Skin mounted (what we use)
Bone pins (pins crewed into bone)
Rigid clusters
Combination

Question 4

What are the red/green/blue/black markers used for in modelling?

Answer 4

Red - Segment definition and tracking
Green - Tracking
Blue - Segment definition only
Black - Virtual markers for segment definition and tracking

Question 5

How do we model and track a pelvis?

Answer 5

Using a GCS

Equations used to estimate the location of hip joint within pelvic coordinate system (as can’t measure bottom of pelvis)

Question 6

How do we model and track a femur?

Answer 6

Using 2 LCS (1 at hip, 1 at knee)

Marker and equation used to estimate hip joint - then creates a right angle triangle to measure area of

Question 7

How do we model and track a tibia?

Answer 7

Using 2 LCS (1 at ankle, 1 at knee)
Medial and lateral markers allow calculation of joint centres
Right angles allow us to calculate easily

Question 8

Why do we use models?

Answer 8

To identify segments to create our model
Then allows us to calculate joint angles as we move
Can complete performance trials with fewer markers