prostate movement-prone vs supine

I came across this while searching "deep breathing prostate" on google, http://www.ncbi.nlm.nih.gov/pubmed/10974443.
[h=4]RESULTS:[/h]During normal breathing, maximal movement of the
prostate markers was seen in the prone position (cranial-caudal [CC]
range: 0.9-5.1 mm; anterior-posterior [AP] range: up to 3.5 mm). In the
supine position, prostate movement during normal breathing was less than
1 mm in all directions. Deep breathing resulted in CC movements of
3.8-10.5 mm in the prone position (with and without an aquaplast mold).
This range was reduced to 2.0-7.3 mm in the supine position and 0.5-2.1
mm with the use of the false table top. Deep breathing resulted in AP
skeletal movements of 2.7-13.1 mm in the prone position, whereas AP
skeletal movements in the supine position were negligible

so you will have greater prostate movement when lying on your stomach instead of your back.