Does using a yoga ball really help you dilate ?

It helps baby get in a better position and open your hips to make room and works with gravity. 

Deep squating helps bring baby down lower which helps aid effacement and dilation and while you bounce on a yoga ball you get into a kind of squat so it is considered an aid. But best of all it helps get baby low and in proper position

I delivered my baby a few days after using a yoga ball lol

So I am a FTM so expected to be late (which seems to be the pattern with myMom and sisters births as well). That being said, I have been walking, squatting, and bouncing away on my yoga ball like crazy.  While I wasn't dilated at my 39 week appointment last week, my cervix HAD softened (was still high and hadn't thinned yet). I have continued this pattern and feel a lot more muscle fatigue, pelvic pressure, etc. as baby continues to move down and put pressure on my cervix.  I have an appointment today (40 weeks and 3 days) to see how things have progressed.  I am HOPING for further progress, but we shall see. Do not expect instant results.  I think it helps move baby down, which in turn helps place pressure on the cervix, which then helps thin the cervix and dilate.  But this all has to do with your body and if it is ready yet.

I used mine constantly and baby still came 3 days late. I think it could help with lowering baby but not sure it really helps with much else. At least not in my case