Dust on my heels

I'm trying to figure out if "dust on my heels" means "always on the move (kicking up dust)" or the opposite "been sitting in one place for a long time (gathering dust)". I can't find an answer anywhere and I'd love to know! Thanks.

There is a phrase that goes something like: I'm going to shake the dust of this town from my heels. So I am guessing that if you have dust still on your heels, you've stayed in one place a long time.