Controlled breathing has me carefully managing the beginning of an in-breath, then letting go in the middle, then again paying close attention at the end of the in-breath (same in the out-breath, btw).
I wonder if that pattern expands to all cyclical processes: that the beginnings and endings, when things are slowly accelerating or decelerating, are the moments where more careful form needs to be ensured, while the middle section is to let oneself go.
A day, for instance: carefully starting it, carefully ending it, but letting it carry you during the mid-section.
On even physical exercise where one needs to put some reps: carefully execute the first ones, then letting go, then carefully executing the last ones.