What pace is a Brisk walk?
Brisk: What pace is a Brisk walk? - Active 10
I’m not sure of the pace that the app counts... maybe someone else can help there.
Active 10 is all about raising the heart rate during the walk... one description of it is to walk at a pace where you can talk in full ungasped sentences, but not sing! If you can use BBC iPlayer, have a look at the Truth About episode on getting fit. Active 10 and some other things are analysed there and also demonstrated
Anything above 3mph.