Changing colliders during animations?

Hi all,
I set up some sprite animations using mecanim for a player character.
In the frames the player moves but the collider (circle collider2d in my case) of course stays at the 1st frame location.
What is the process to change the colliders to match a frame?
My research says to set colliders for each frame individually and then swap out colliders but I am not quite sure how to do this.
Thanks for any input

 

Answer here - duh for not finding before
http://www.raywenderlich.com/61532/unity-2d-tutorial-getting-started

However any better methods?
Nightmare for multiple frames and animations of one sprite