Dear Inmaculada,

Great question! I have often wondered about this.

I think the cross leg (usually my right - I wonder if it is always the
right?) pushes the supporting tibia backwards and thereby forces the
knee into a stable posture, with the ground reaction vector well
forwards. This allows the quadriceps to be relaxed with confidence.

Two possibly related questions are:

1. Why do customers prefer bars to have a rail on which to put one foot?
2. Why do birds stand on one leg when they are asleep?

Chris
--
Dr. Chris Kirtley MD PhD
Associate Professor
Dept. of Biomedical Engineering
Catholic University of America
620 Michigan Ave NE, Washington, DC 20064
Tel. 202-319-6134, fax 202-319-4287
Email: kirtley@cua.edu
http://engineering.cua.edu/biomedical/faculty/kirtley

---------------------------------------------------------------
To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------