I used the Flipbelt the other day with the phone below my stomach at the waist, and after seeing the workout app for Watch report pretty slow pace times, I decided to take the iPhone out of the flip belt and carry it in my hand, which greatly improved accuracy....... the flip belt I have is a bit tight, so I wonder if my body is getting in the way of GPS for the iPhone as I have a little bit of a belly, maybe I should put the iPhone on my back instead of my front?