A periodization model where volume falls and intensity rises steadily across a block, moving from many light reps to few heavy ones.
The classic version runs 4 x 12 at 65 percent in weeks 1 to 4, 4 x 8 at 75 percent in weeks 5 to 8, 4 x 5 at 82 percent in weeks 9 to 12, then 3 x 3 at 88 percent before a test. Each phase builds on the one before: size first, then strength, then expression of it.
It is the simplest model to write and the easiest for a client to follow, which is why it still dominates beginner and intermediate programming. Its weakness is that the qualities trained in week 2 have started to fade by week 12, which is what undulating and block models exist to solve.
Use it with clients who have one clear goal and a date, and who do not need to hold several qualities at once.