3 dimensional Soccer kick analysis question

[Yumeng Li]

Dear members,
I am doing a research on soccer kick analysis. The purpose is to compare the differences in the kinematics of kicking movement in different kick directions in a penalty kick. But I just have 4 Vicon cameras that work, so the calibration volume is very limit. What can I do to get data of all the approach and kicking movement?
Or any other methods to get 3D data rather than using Vicon system?
Thanks.
Yumeng Li,
University of Manitoba
umli499@cc.umanitoba.ca

[Bertrand Bru]

Re: 3 dimensional Soccer kick analysis question

Hi,

Can you tell us a little bit more about the project? The camera placement highly depends on what you want to analyse!

Are you interested in analysing the kinematics of both legs or just the one which will hit the ball?

To analyse the kinematic of the leg kicking the ball with 4 Vicon cameras, I recommend this approach:

• Place all cameras nearly linearly on the the external side of the kicking leg and place the ball at 1/3 of the capture volume. This will give the possibility to capture two steps before the kick and the stabilization phase after the kick.

• Position the markers on the external side of the foot, shank and thigh (not necessarily on the joints). It can be only technical markers.

• Digitise the anatomical landmarks (e.g. the medial femoral epicondyle, medial molleolus, first metatarsal). The procedure will give you the possibility to track virtual markers which cannot be viewed by the cameras, this is very useful when the number of camera is limited. Refer to the work of Cappozzo et al. (CAST protocol):
  a) Position and orientation in space of bones during movement: anatomical frame definition and determination. Clin Biomech (Bristol, Avon). 1995, vol: 10, pages: 171-178.
  b) Surface-marker cluster design criteria for 3-D bone movement reconstruction. IEEE Trans Biomed Eng. 1997, vol: 44, pages: 1165-1174.

The digitising session can be done before or after the experiment but it is very important that the markers don't move during either of these phases. The pointer (tool required for the digitising session) can easily be done (cf picture of the first article).
If you need, I can give you more details on the digitizing procedure.

Best regards,

Bertrand