Every serious lifter autoregulates. The question is with what signal. Most rely on RPE or reps-in-reserve, which is useful but subjective, or on a flat percentage of one-rep max that ignores how the body actually feels on the day. There's a third option, and the evidence over the last decade has quietly made it the most defensible: end the set when the bar slows down by a defined amount. This isn't a new idea, but the trials behind it are now mature. We have RCTs, meta-anal