User guide

Charnwood Dynamics Ltd. Coda cx1 User Guide - Gait Analysis II - 1
CX1 USER GUIDE - COMPLETE.doc 26/04/04 71/162
Foot Segment
This is defined by three points: the first is the AnkleCentre, as defined above within the
shank segment; the other two reference points, ‘Heel’ and ‘Toe’, are simply medially offset
from the Heel and Toe markers by half an ankle-width, w, (Patient Data again). The
principal axis of the foot is taken to be parallel to the line between Heel and Toe markers;
this is the local x axis.
Thus:
u
x
= U
x
(M
Toe
- M
heel
)
u
z
= GS
z
(u
x
, M
Ankle
- M
heel
)
u
y
= U
y
(u
x
, u
z
)
A
Centre
= ½ (P
latAnkle
+ P
medAnkle
) (as above)
P
heel
= M
heel
+ ½ wu
y
P
Toe
= M
Toe
+ ½ wu
y
P
latknee
= M
knee