Will the pedometer work when the phone is in your hand?

[mattl2]

I have a LG G4 with Lollipop, not that it should matter. I was debating with my friend lately about how a phone counts steps. He said it would still count if you were talking on it or using the internet, because it utilizes GPS tracking (he has an iphone.) I think the accelerometer actually measures the swing of your leg to count steps and if you're using the phone in your hand as you're walking those steps wouldn't be counted. Thoughts?