For those of you marvelling at Romans having a five foot (1.5 m) stride, a Roman pace was two steps, counted from the left foot down to left foot down again.
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.