What Even is “Rate of Perceived Exertion” (RPE)?
RPE, or Rate of Perceived Exertion, is a way to measure training intensity based on effort rather than strict percentages. Instead of relying on a fixed number (like lifting 80% of your max), RPE allows you to adjust based on how you feel on a given day, making it a more flexible and individualized approach.
How RPE Works
RPE 10 = Max effort, no more reps possible.
RPE 9 = Maybe one rep left in the tank.
RPE 8 = Two reps left
Etc.
RPE 0 really doesn’t exist because that would mean you’re literally exerting NO energy, and there’s no such thing at the gym!
Why Train Close to Failure (RPE 9-10)?
Science shows that to maximize muscle growth and strength, you need to recruit high-threshold motor units—essentially, the strongest muscle fibers that only activate when you're pushing close to failure. Research suggests that stopping too far from failure (RPE 5-6) may not provide enough stimulus for optimal adaptation. By training at RPE 9-10, you're ensuring you hit those key muscle fibers, leading to better strength and hypertrophy gains.
Why I Use RPE Instead of Percentages
As a coach, I prefer RPE over fixed percentages because your body isn’t a machine—your performance fluctuates based on sleep, nutrition, stress and recovery. On a bad day, 80% might feel like a max effort lift (RPE 10), while on a good day, it might feel like an easy RPE 7.
RPE allows you to:
Auto-regulate your training—adjust intensity based on how you feel that day.
Build awareness of your own effort levels, which is crucial for long-term progress.
Avoid unnecessary fatigue while still pushing hard enough to make gains.
For beginners, learning RPE takes time. Start by taking some sets to failure to understand what RPE 10 feels like, record your lifts, and reflect on whether your rating was accurate. Over time, you'll develop a more intuitive sense of effort, allowing you to train smarter and make consistent progress.