If you’re a musician (singer or instrumentalist), you probably count a two-part event as “one and.” After all, that’s how you count bars of music. And the “and” in this case, is often half of the bar.
If you’re a cook, you probably count “half” (or “and”), “one, and a half, two.” Etc.
So what do you do if you’re exercising and you have a two-part exercise to count? I’ve tried it both ways during my morning exercises and the best way is as a musician: “one and two and …”
Glad you asked!