RPE-based training: what it is and why it matters

RPE, or rate of perceived exertion, is a simple way to record how hard a set felt — usually on a 1–10 scale tied to how many reps you had left in reserve. It turns effort into data your training can respond to.

Most people start strength training with numbers: 3 sets of 10, 80kg on the bar, 75% of one-rep max, add 2.5kg next week. Numbers are useful. They give structure, progression, and accountability.

But numbers do not always tell the whole story.

A weight that feels smooth one week can feel brutally heavy the next. A planned session can land differently depending on sleep, stress, soreness, nutrition, recovery, confidence, injury niggles, and how well the previous sessions went. This is where RPE-based training becomes valuable.

In modern strength training, RPE is usually linked to reps in reserve, or RIR. Instead of only asking, "What weight did you lift?", RPE asks, "How close was that set to your limit?"

That distinction matters. For a system like Adaptiv, which reads your recorded RPE to adjust load and volume, RPE is not just a feedback score. It is a signal. It helps the programme understand whether the prescribed session was too easy, too hard, or about right, and then adapt future training accordingly.

What is RPE?

The original RPE concept comes from Gunnar Borg's work on perceived exertion (Borg, 1982). The classic Borg RPE scale runs from 6 to 20 and was designed so ratings increase broadly in line with oxygen consumption and heart rate during steady-state exercise. Borg also developed the CR10 scale, a broader 0–10 category-ratio scale used across sport, training, ergonomics, physiotherapy, and other settings.

In resistance training, however, most coaches and apps now use a more specific version: the 1–10 RPE scale based on reps in reserve. This approach was developed and validated because lifters needed a more practical way to describe effort during a set (Zourdos et al., 2016). A general "that felt hard" rating is useful, but "I had 2 reps left" is much more actionable.

A simple RPE-to-RIR guide looks like this:

The 1–10 RPE scale, mapped to reps in reserve.

Helms and colleagues describe this RIR-based RPE approach as a more precise resistance-training tool, because it adjusts loads to match the athlete's capability on a set-by-set basis and may better gauge intensity near limit loads (Helms et al., 2016).

So, if your programme says:

Bench press: 3 sets of 8 @ RPE 8

…it means you should choose a load that allows you to complete 8 good reps while finishing each set with about 2 reps left in the tank. If you know a recent max, our RPE calculator turns a target RPE into a working load.

The goal is not simply to hit the heaviest possible weight. The goal is to hit the right training stimulus.

Why fixed percentages can fall short

Traditional strength programmes often prescribe load as a percentage of one-rep max. For example:

Squat: 5 sets of 5 at 75% of 1RM

This can work well, especially in structured strength blocks where a lifter has an accurate and recent one-rep max. Percentage-based training is simple, objective, and easy to plan.

The problem is that a percentage does not always equal the same level of effort.

One person might perform 10 reps at 75% of their one-rep max. Another might only manage 6. Even the same person might perform differently depending on fatigue, exercise selection, technical efficiency, or the day they are having. Research has shown considerable variation in the number of repetitions people can complete at the same relative intensity. In one study of older and younger adults, participants showed considerable interindividual variability in repetitions completed at 60% and 80% of 1RM across three resistance exercises (Grosicki et al., 2014).

That is the central weakness of percentages: they assume that today's capacity is the same as the number written in the programme.

But real training is messier than that.

Your true strength on a given day can fluctuate. A 100kg squat might be an RPE 7 when you are well rested and an RPE 9 when you are under-recovered. The load is the same, but the stress on the body is not.

RPE solves this by shifting the question from "What percentage should this be?" to "How hard should this set be today?"

That makes RPE especially useful for real-world training, where recovery and performance are rarely perfectly predictable.

RPE and autoregulation

RPE-based training is a form of autoregulation. Autoregulation means adjusting training based on current performance or perceived capability rather than following a fixed plan no matter what.

A fixed plan might say: "Do 80kg for 8 reps."

An autoregulated plan might say: "Do 8 reps at RPE 8."

On a good day, that might be 82.5kg. On an average day, it might be 80kg. On a poor recovery day, it might be 75kg. The target effort stays the same, but the load adjusts to the person.

This is why RPE is so useful for adaptive programming. It allows the programme to respond to what actually happened, not just what was predicted.

If a lifter records several sessions where planned working sets are coming in at RPE 9–10, the programme can infer that the current load, volume, or progression rate may be too aggressive. If they repeatedly record RPE 5–6 for sets intended to be challenging, the programme can safely consider increasing load, reps, or volume.

That feedback loop is the difference between a static plan and a responsive one.

Research broadly supports the idea that autoregulation can be at least as effective as fixed loading, and sometimes better for strength. A 2021 systematic review and meta-analysis found that autoregulated methods were more effective than fixed-loading methods for maximum strength in athletes, while also noting that methods such as APRE, RPE, and velocity-based training all fall under the autoregulation umbrella (Zhang et al., 2021).

However, the evidence should be interpreted carefully. Another systematic review and meta-analysis found that autoregulated and standardised load prescription produced similar improvements in 1RM strength, with no significant overall difference (Hickmott et al., 2022). Part of the reason these reviews diverge is population: the first looked at athletes, the second at resistance-trained individuals more broadly.

The fairest conclusion is this: RPE-based training is not magic, and fixed percentages are not useless. Both can work. But RPE often has the practical advantage, because it helps match the planned training stimulus to the lifter's actual readiness on the day.

What the research says about RPE versus percentage training

One of the most relevant studies compared RPE-based loading with percentage-based loading in resistance-trained men over 8 weeks (Helms et al., 2018). Both groups trained squat and bench press three times per week using matched sets and repetitions. Both groups improved strength and muscle thickness. Between-group differences were not statistically significant, but the authors concluded that RPE-based loading may provide a small 1RM strength advantage in a majority of individuals.

That is an important point. RPE did not produce a completely different outcome. It simply allowed training to better reflect the individual.

In practice, that is often enough.

Small differences matter when repeated across weeks and months. A programme that constantly overshoots can leave the lifter fatigued, sore, and inconsistent. A programme that constantly undershoots can slow progress. RPE helps narrow that gap.

It also helps manage fatigue. A 2023 study on resistance-trained men and women found that training closer to failure produced greater acute neuromuscular fatigue and more negative perceptual responses (Refalo et al., 2023). Failure created more fatigue than stopping at 1 RIR, which created more fatigue than stopping at 3 RIR. The authors concluded that there was a linear relationship between proximity to failure and both acute fatigue and negative perceptual responses.

That is exactly why RPE matters for programming. Training hard is necessary. Training maximally all the time is not.

Why RPE matters for muscle and strength

For strength, RPE helps ensure that heavy work is heavy enough without becoming reckless. A set at RPE 8 or 9 can provide a strong stimulus while leaving enough margin to maintain technique and recover for future sessions.

For muscle growth, RPE helps control proximity to failure. Hypertrophy training generally benefits from sets being reasonably close to failure, but not every set needs to be an all-out grinder. RPE allows the programme to prescribe effort more precisely.

Effort can also be structured across a training block — rising through the weeks, then easing off. For example:

• Early in a block: 3 sets of 10 @ RPE 7
• Middle of a block: 3–4 sets of 8–10 @ RPE 8
• Harder week: 4 sets of 8 @ RPE 8–9
• Deload or recovery week: 2–3 sets @ RPE 6–7

The exercises, reps, and loads still matter. But RPE adds an internal measure of how demanding the work actually was.

This is particularly useful because fatigue is not only about weight lifted. Volume, exercise selection, range of motion, tempo, sleep, stress, and recovery all influence how hard a session feels. RPE captures some of that complexity in a single number.

How Adaptiv uses RPE

In Adaptiv, RPE is part of the feedback loop between you and the programme. The system prescribes a session with a target effort, then uses your recorded RPE to adjust future training.

Say you're prescribed dumbbell shoulder press at 3 sets of 10 @ RPE 8, and you log RPE 6, 6, and 7:

• Observation: every set came in below the RPE 8 target.
• Reasoning: the load was lighter than the session intended, so the stimulus was too easy to drive progress.
• Action: the next session raises the load, adds reps, or increases volume to bring effort back to target.

The reverse holds too. Log RPE 9, 10, and a failed set before the target reps, and the reasoning flips — the prescription outran your capacity that day, so the next session pulls load or volume back and slows the progression.

This is the loop ORA runs on every session: not a weekly nudge in one direction, but a read of what actually happened, followed by a specific adjustment. A good programme should not blindly push harder every week. RPE is how you tell it what happened.

Common mistakes with RPE

The biggest mistake is treating RPE as a vibe rather than a skill.

RPE improves with practice. Many lifters are poor at estimating reps in reserve at first. Some underestimate effort and think every set is easier than it is. Others overestimate effort and rate any discomfort as RPE 9.

Research supports this caution. Hackett and colleagues found that people were more accurate at estimating repetitions to failure when they were closer to failure, with greater errors when more reps remained (Hackett et al., 2017). A later scoping review and meta-analysis found that people tended to underpredict repetitions to failure by around 1 rep on average, with accuracy improving when predictions were made closer to failure, with heavier loads, or in later sets (Halperin et al., 2022).

That means RPE is useful, but it needs calibration.

Another common mistake is using RPE as an excuse to avoid hard work. If every working set is recorded as RPE 8 but you could clearly have done five more reps, the data becomes less useful. The programme may think the training stimulus is appropriate when it is actually too easy.

The opposite mistake is also common: turning every set into RPE 10. This might feel productive, but constantly training to failure can create unnecessary fatigue, reduce performance across later sets, and make recovery harder. The aim is not to suffer. The aim is to apply the right dose.

How to get better at using RPE

The best way to improve RPE accuracy is to practise it honestly.

After a set, ask: "With good form, how many more reps could I have completed?"

Not ugly reps. Not half reps. Not reps with technique falling apart. Good reps.

Then convert that answer into RPE. If you had 2 reps left, it was roughly RPE 8. If you had 1 rep left, it was roughly RPE 9. If you had none left, it was RPE 10.

It can also help to occasionally perform a controlled set close to failure on safer exercises such as machine rows, dumbbell presses, leg curls, or cable movements. This teaches what 3 RIR, 2 RIR, and 1 RIR actually feel like. The goal is not to test constantly, but to build awareness.

A 2024 scoping review found that RIR scales appear feasible and useful for prescribing and adjusting resistance-training intensity, especially when the goal is to target a desired proximity to failure. The same review noted that RIR predictions should be made close to task failure to improve accuracy (Bastos et al., 2024).

So RPE is not just a number you type into an app. It is a skill that improves the quality of your training data.

RPE versus percentages: which is better?

The answer is not either/or.

Percentages are useful for structure. RPE is useful for adjustment.

A percentage-based plan might provide the initial framework. RPE then helps fine-tune the session. For example:

Squat: 4 sets of 5 at around 75%, aiming for RPE 7–8

This gives the lifter a starting point, but also permission to adjust. If 75% feels like RPE 9 today, reduce the load. If it feels like RPE 6, increase slightly.

This blended approach often works best. Percentages provide direction. RPE provides feedback.

For beginners, RPE can be kept simple. Instead of asking for exact ratings, the programme can use broad effort zones:

• Easy: RPE 5–6
• Moderate: RPE 6–7
• Challenging: RPE 7–8
• Hard: RPE 8–9
• Maximal: RPE 10

For intermediate and advanced lifters, more precise RPE targets become valuable, because they can better judge proximity to failure and tolerate more nuanced progression.

The real value of RPE

The real value of RPE is not that it replaces programming. It makes programming more responsive.

A fixed programme says: "This is what you should do."

An adaptive programme asks: "What happened when you did it?"

That second question is where progress becomes more personal.

RPE helps identify whether training is landing as intended. It helps manage fatigue, guide progression, and avoid the two most common problems in training: doing too much too soon, or not doing enough to create change.

For lifters, it makes training more intuitive. For coaches, it provides a simple monitoring tool. For adaptive systems like Adaptiv, it creates a feedback signal that can adjust load and volume over time.

That is why RPE matters. It turns training from a rigid prescription into a conversation between the programme and the person doing the work.

Common questions

What does RPE mean in strength training?

RPE stands for rate of perceived exertion — a 1–10 rating of how hard a set felt. In resistance training it's tied to reps in reserve: an RPE of 8 means you finished with about 2 good reps left. It measures effort, not just the weight on the bar.

What is an RPE of 8?

An RPE of 8 is a hard but controlled set with roughly 2 reps left in reserve. You could have done 2 more good reps with proper form before reaching failure. It's a common target for building strength and muscle without the fatigue cost of training to failure every session.

Is RPE better than percentage-based training?

Neither is strictly better. Percentages give clear structure; RPE adjusts that structure to how you're recovering on the day. Research shows both build strength effectively, with RPE offering a small practical edge by matching effort to your actual capacity rather than a number set weeks ago.

How do I work out my reps in reserve?

After a set, ask how many more good reps you could have completed with proper form — not ugly, half, or breakdown reps. That number is your reps in reserve. Two left is roughly RPE 8, 1 left is RPE 9, none left is RPE 10. Accuracy improves with practice.

Key takeaways

RPE stands for rate of perceived exertion. In strength training, it is usually linked to reps in reserve, meaning how many good reps you had left at the end of a set.

RPE-based training helps adjust load and volume based on how hard training actually feels, not just what was planned.

Fixed percentages can work, but they do not always reflect daily readiness or individual differences in how many reps someone can perform at a given percentage of 1RM.

The evidence suggests RPE-based and percentage-based training can both be effective. RPE's main advantage is practical: it helps match the training stimulus to the lifter on the day.

RPE is a skill. It becomes more accurate with practice, especially when you learn what 3, 2, and 1 reps in reserve actually feel like.

For Adaptiv, RPE is a key feedback signal. By recording how hard sets feel, you help the system adjust future training so the programme stays challenging, realistic, and matched to how you're actually recovering.

References

1. Borg, G.A. (1982). Psychophysical bases of perceived exertion. Medicine & Science in Sports & Exercise, 14(5), 377–381. https://doi.org/10.1249/00005768-198205000-00012
2. Zourdos, M.C., Klemp, A., Dolan, C., et al. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research, 30(1), 267–275. https://doi.org/10.1519/JSC.0000000000001049
3. Helms, E.R., Cronin, J., Storey, A., & Zourdos, M.C. (2016). Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength and Conditioning Journal, 38(4), 42–49. https://doi.org/10.1519/SSC.0000000000000218
4. Helms, E.R., Byrnes, R.K., Cooke, D.M., et al. (2018). RPE vs. percentage 1RM loading in periodized programs matched for sets and repetitions. Frontiers in Physiology, 9, 247. https://doi.org/10.3389/fphys.2018.00247
5. Zhang, X., Li, H., Bi, S., et al. (2021). Auto-regulation method vs. fixed-loading method in maximum strength training for athletes: a systematic review and meta-analysis. Frontiers in Physiology, 12, 651112. https://doi.org/10.3389/fphys.2021.651112
6. Hickmott, L.M., Chilibeck, P.D., Shaw, K.A., & Butcher, S.J. (2022). The effect of load and volume autoregulation on muscular strength and hypertrophy: a systematic review and meta-analysis. Sports Medicine – Open, 8, 9. https://doi.org/10.1186/s40798-021-00404-9
7. Refalo, M.C., Helms, E.R., Hamilton, D.L., & Fyfe, J.J. (2023). Influence of resistance training proximity-to-failure, determined by repetitions-in-reserve, on neuromuscular fatigue in resistance-trained males and females. Sports Medicine – Open, 9(1), 10. https://doi.org/10.1186/s40798-023-00554-y
8. Grosicki, G.J., Miller, M.E., & Marsh, A.P. (2014). Resistance exercise performance variability at submaximal intensities in older and younger adults. Clinical Interventions in Aging, 9, 209–218. https://doi.org/10.2147/CIA.S55719
9. Hackett, D.A., Cobley, S.P., Davies, T.B., Michael, S.W., & Halaki, M. (2017). Accuracy in estimating repetitions to failure during resistance exercise. Journal of Strength and Conditioning Research, 31(8), 2162–2168. https://doi.org/10.1519/JSC.0000000000001683
10. Halperin, I., Malleron, T., Har-Nir, I., et al. (2022). Accuracy in predicting repetitions to task failure in resistance exercise: a scoping review and exploratory meta-analysis. Sports Medicine, 52(2), 377–390. https://doi.org/10.1007/s40279-021-01559-x
11. Bastos, V., Machado, S., & Teixeira, D.S. (2024). Feasibility and usefulness of repetitions-in-reserve scales for selecting exercise intensity: a scoping review. Perceptual and Motor Skills, 131(3). https://doi.org/10.1177/00315125241241785