I’m sure I’m not the only one or first to try this, but I’m not sure what it’s called. Let’s take good ole barbell bench for example. Basically you warm up with whatever maybe 40% of your 1 rep max then proceed to do doubles up to or close to your 2 rep max. This is all to prepare you for your working sets. Theory being you have a heavy load, do a couple of reps, then proceed to do your working sets with lighter weight which feels even lighter.