MariposasRPE (Rate of Perceived Exertion)
RPE, or Rate of Perceived Exertion, is a self-reported scale that measures how hard an exercise feels in the moment, based on your breathing, muscle fatigue, and overall strain. The most common version used in strength training runs from 1 to 10, where an RPE 10 means you gave absolutely everything and could not have done another rep, while an RPE 6 might feel like a brisk warm-up with plenty left in the tank. The concept originally comes from Swedish psychologist Gunnar Borg, whose classic scale ran from 6 to 20 and was designed to loosely track heart rate during cardio, but the simpler 1 to 10 version has become the standard in gym settings. The big nuance most people miss is that RPE is relative to your current state: the same weight on a barbell can feel like an RPE 7 on a well-rested Tuesday and an RPE 9 on a Friday after four hard training days. This makes RPE a more honest training tool than blindly following a fixed percentage of your max, because it accounts for sleep, stress, hydration, and daily variation in readiness. Coaches use it to keep athletes training hard enough to make progress without grinding into the kind of fatigue that quietly stacks up and wrecks performance over time.
Example
A powerlifter is programmed to squat at RPE 8 for three sets of four reps, meaning she should pick a weight where she finishes each set feeling like she had roughly two reps still available. On the first set she loads 185 pounds, finishes four reps, and honestly gauges she had about two more in her, so she stays at that weight rather than chasing a number. If she had loaded too heavy and finished gasping with nothing left, that would be an RPE 10, overshooting the session target and accumulating more fatigue than planned.