From what I understand this is a question about the position of the pelvis. The pelvis should be neutral as in any athletic pursuit. Stand up and allow your abs to give up and retain no tension causing your bottom to stick out, now rotate the pelvis upwards by applying tension in the abs. Rotate as far as you can until the tail bone starts to tuck under. This requires a lot of tension. Now maintaining some tension in the abs ,feel the pelvis in a mid way between the 2. This is roughly pelvic neutral and part of a good athletic stance.
You can do the same lying on the floor. Feel a big arch under your spine when relaxed, now press the spine into the floor. A neutral pelvis will be when the spine is just about closing the arch but not applying too much pressure.
Hope this helps.