Isometric middle split (MSs-se24) question

During each position, should I be contracting as if I were trying to pull my legs together, or is it a contraction straight through the legs?

The first stages are mostly there to help you warm up to the final position and to gauge how far you should go. In the final stage,  if you're wide enough your question will automatically answer itself or you'll wind up on your behind

Thanks. I'll be working on this tomorrow, guess I haven't really gone far enough as it seemed a bit too easy.