Understanding RPE and RIR: Mastering Workout Intensity in Strength Training
When it comes to getting stronger, intensity matters. But how do you really know if you’re training hard enough—or too hard?
Enter two powerful tools: Rate of Perceived Exertion (RPE) and Reps in Reserve (RIR). These are simple, intuitive ways to monitor and adjust workout intensity, helping you get better results, avoid burnout, and train smarter over time.
Let’s break down what they are, how to use them, and why they matter.
What is RPE?
RPE (Rate of Perceived Exertion) is a scale that rates how hard a set feels. In strength training, we typically use a 1-10 scale, where:
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10 RPE = Max effort. You couldn’t do another rep or add more weight. Absolute limit.
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9 RPE = Could’ve done one more rep.
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8 RPE = Two reps left in the tank.
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7 RPE = Three reps left.
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And so on.
Originally developed for endurance training, RPE has become popular in the lifting world because it accounts for how you’re actually feeling on a given day—not just what’s on the paper.
What is RIR?
RIR (Reps in Reserve) is essentially the flip side of RPE. Instead of rating how hard something felt, you estimate how many reps you could’ve done before failure.
For example:
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If you finish a set and feel like you had 2 more reps in you → that’s 2 RIR.
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If you hit failure and couldn’t do another rep → that’s 0 RIR.
It’s basically a more objective way of talking about effort. And conveniently, it lines up with RPE like this:
| RIR | RPE |
|---|---|
| 0 | 10 |
| 1 | 9 |
| 2 | 8 |
| 3 | 7 |
Why Use RPE or RIR?
Strength training isn’t just about doing more—it’s about doing the right amount consistently. RPE and RIR help with:
✅ Auto-regulation
Not every day is the same. Some days you’re dragging. Others you’re on fire. Using RPE or RIR lets you adjust intensity without derailing your plan.
✅ Better Progression
They help you avoid training too light (wasting time) or too heavy (risking injury). Instead, you build in smart progression based on actual effort.
✅ Individualization
Two lifters might both squat 225 lbs—but for one it’s a breeze, and for the other it’s near max. RPE/RIR keeps training intensity appropriate for each person.
How to Use RPE and RIR in Your Training
Beginners: Start by building awareness. After a set, ask yourself: “How many more reps could I have done?” Track your answers. Over time, your accuracy improves.
Intermediate to Advanced Lifters: Program with RPE or RIR targets. For example:
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Week 1: 3×8 @ RPE 7 (3 RIR)
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Week 2: 3×8 @ RPE 8 (2 RIR)
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Week 3: 3×8 @ RPE 9 (1 RIR)
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Week 4: Deload or test a max effort set @ RPE 10
This style of progressive overload with autoregulation lets you push hard without burning out.
Final Thoughts
RPE and RIR aren’t just tools for elite athletes—they’re game-changers for anyone serious about strength. Whether you’re chasing a new PR, building muscle, or just want to train smarter, paying attention to how sets feel gives you a better sense of how to manage intensity, recover, and progress long term.
Remember: It’s not about crushing yourself every session—it’s about consistent, intelligent effort over time.