Stretching Difficulty

[Eyedoc]

Coach,

I am having difficulties with one particular stretch I do in Karate class. It is a variation of a Hindu push up but with a very wide foot position. As you descend into the push-up the pelvis moves down to the floor as you push the shoulders up to the top of the push-up. I cannot get my pelvis to move to the floor unless my feet are together. What is the limitation here?

If it makes any difference I am 42 years old in decent shape and I have been training in karate for the past 5 yrs.

Thanks,

Jonathan