In my experience many people define pace the same way today. We were taught in Boy Scouts how to pace off a distance measuring 5 feet per pace, or every other footfall.
Averages out better.
My hypothesis is this: Actually try to count every foot when you’re out. If you count only every second footfall, you can mentally go "a-one-a-two-a-three" and so on, but counting every foot, there are just too many of them. At least I get brain overload from it.
They're both shortcuts to count things with half as much counting.
It always got complicated with obstacles though. Especially since most of them didn't know how to do trigonometry yet. We usually just had them estimate which they got pretty good at after a few hours of counting paces.