One of my students came to me a few months ago as a newbie skater. She could go frontwards and backwards and could do two foot spins, but she hadn't been able to figure out a one foot spin yet. The problem is, before we could get her one foot spin to work, she had to undo some unhelpful muscle memory she'd picked up in her two foot spin and teach her how to center a spin correctly. Then, we started working on the one foot spins.