What does RPE mean in strength training and where does it come from?

RPE comes from the work of Gunnar Borg, not powerlifting

RPE stands for “rating of perceived exertion.” Gunnar Borg and Hans Dahlström were already studying the relationship between perceived effort and physical work capacity on an ergometer in 1962. Their subject was the perception of exercise and its relationship to physiological measures, not the number of reps left under a barbell.

In 1970, Borg published a category scale that became the Borg 6–20 scale. Its numbers were chosen in part to roughly track a heart-rate range of 60 to 200 beats per minute in young adults. That historical rationale does not let you automatically convert your RPE into heart rate: responses vary across people, activities, and conditions. Borg and Dahlström, 1962, Borg, 1970

In 1982, Borg summarized the psychophysical foundations of perceived exertion and also presented a method that combined categories with ratio properties, laying the groundwork for the CR10 scale. These tools were later used in medicine, endurance exercise, and many sports. It would therefore be inaccurate to say that powerlifting, bodybuilding, or gymnastics invented RPE. Borg, 1982, Lopes et al., 2022 — history and uses of perceived exertion

Borg, session-RPE and RPE per set do not measure the same thing

The Borg 6–20 and CR10 scales assess perceived exertion during or after an activity. Session-RPE asks for one overall rating of the entire workout; that rating can be multiplied by the workout duration to estimate internal load in arbitrary units. A long, moderate workout can therefore represent a substantial load even when no strength-training set approaches failure.

Foster and colleagues studied this session-RPE method for quantifying continuous, intermittent, and prolonged exercise. It tracks overall load; it does not predict how many pull-ups or squats remained possible at the end of a particular set. Foster et al., 2001

By contrast, the RPE-RIR scale used in strength training asks after each set, “With the same technique, how many more reps could I have done?” Before interpreting a program, identify the scale, when it is measured, and what it rates. A session score of 8 out of 10 does not mean every set was performed at RPE 8.

• Place effort intensity within the fundamentals of strength training →

Powerlifting popularized RPE anchored to RIR

Internationally, powerlifting is the sport of maximizing the combined total of the squat, bench press, and deadlift. The French federation uses a narrower national convention: it calls unequipped competition “Force Athlétique” and equipped competition “Powerlifting.” Because daily performance varies, a fixed percentage of a lifter's maximum can sometimes be too light or too heavy. French Strength Federation

In the late 2000s, notably through his Reactive Training Manual published in 2008, powerlifter and coach Mike Tuchscherer popularized an adaptation of RPE tied to the reps still possible within the powerlifting community. This approach helped lifters autoregulate load and volume; it did not originate the concept of perceived exertion that Borg had studied decades earlier. Reactive Training Systems — manual overview, Helms et al., 2016

This history explains why strength programs often prescribe “1 rep at RPE 8” or “work up to RPE 9.” The tool solves a specific load-selection problem; it does not mean that everyone seeking an athletic physique needs the heavy singles, testing, and fatigue of a competition cycle.

• Compare powerlifting, bodybuilding, weightlifting, and gymnastics →

Bodybuilding research helped test estimates of remaining reps

In 2012, Hackett and colleagues asked 17 experienced male bodybuilders to perform five sets of ten reps at 70% of their maximum on the bench press and squat. After each planned set, they rated their effort and estimated how many reps remained, then continued to volitional exhaustion. Their estimates better matched the reps actually remaining on later sets, when fatigue brought them closer to failure. Hackett et al., 2012

This small study does not show that bodybuilders invented RIR or that estimates are accurate on every exercise. Instead, it helps explain why the language of reps remaining resonates with hypertrophy-focused lifters: for multi-rep sets, it describes effort intensity more directly than a percentage of 1RM.

Competitive bodybuilding focuses on muscular development and physique presentation; general strength training may pursue a mix of muscle, strength, health, and enjoyment. RIR can help both without imposing the volume, extreme cutting, or stage practices of competitive bodybuilding.

Zourdos and Helms studied and then formalized the RPE-RIR scale

In 2016, Zourdos, Helms, and colleagues published a study of a resistance-training-specific RPE scale anchored to RIR. They tested it with novice and experienced squatters at several intensities. The goal was to represent set effort more effectively than general scales that could not distinguish finely among very hard efforts. Zourdos et al., 2016

That same year, Helms, Cronin, Storey, and Zourdos detailed how to apply it to prescribe and adjust resistance-training sets. Their work gave an already-practical tool a research foundation and shared vocabulary. It did not turn a subjective perception into an exact measurement. Helms et al., 2016

Read the RPE-RIR table as an approximation near failure

On the version used by many strength-training programs, RPE 10 means that no additional full rep appeared possible. RPE 9 leaves about one rep, RPE 8 about two, and RPE 7 about three. Keep the word “about” in mind: you are not directly measuring a hidden reserve.

The mental shortcut “RIR = 10 − RPE” is practical from RPE 7 to 10. Below RPE 7, the scale generally describes a set with at least four reps left, but the relationship becomes too vague to serve as a universal formula. The easier or longer the set, the harder it becomes to count the remaining reps accurately.

• RPE 10 ≈ 0 RIR: no additional full reps.
• RPE 9 ≈ 1 RIR: about one more rep possible.
• RPE 8 ≈ 2 RIR: about two more reps possible.
• RPE 7 ≈ 3 RIR: about three more reps possible.
• Below RPE 7: effort is farther from failure, with no precise universal conversion.

You can improve RIR accuracy, but it remains imperfect

A review with an exploratory meta-analysis found variable error in predictions of reps to failure. Estimates tended to improve when sets were closer to failure and contained fewer reps; training status did not clearly explain accuracy. Experienced lifters can therefore still be wrong. Halperin et al., 2022

Bar speed, muscle burn, and shortness of breath provide clues, but none reveals true RIR by itself. A squat can slow well before failure; breathing can end a set of lunges; an isolation exercise can burn while several reps remain. First define what counts as an acceptable rep.

Use ranges instead of false precision: “1 to 3 RIR” is often more honest than RPE 8.25. If technique, range of motion, or rest periods change, record that instead of comparing numbers as though the sets were identical.

Calibrate your RPE without dangerously testing every set

First choose a stable exercise that is easy to stop: a leg extension, curl, machine row or pulldown, or push-up with a defined technique. On the final set only, state your RIR mentally, then continue to technical failure—the point at which another rep would require substantially shortening the range of motion or changing the movement.

Compare your estimate with the result. If you called 2 RIR and then completed five more clean reps, you underestimated your reserve by three reps. Repeat the calibration a few weeks later under similar conditions. Two or three useful calibrations are better than constant tests to failure that add fatigue.

A small study of fifteen novice young men, whose average age was 17.3 years, found good test-retest reliability when prescribing a 1 RIR load for the bench press and deadlift. This result supports the practical repeatability of the benchmark in this specific context; it proves neither that the true RIR was exactly one nor that the method is universally valid. Lovegrove et al., 2022

Do not seek failure just to verify a number on a heavy squat, a bench press without safeties, a deadlift with deteriorating technique, or a risky gymnastics movement. Use safeties, a competent spotter, or a safer exercise. Stop immediately if you experience acute pain, dizziness, loss of balance, or an uncontrolled movement path.

• Keep the variation, range of motion, load, and rest period consistent.
• State your RIR before extending the set.
• Test only the final set of a safe exercise.
• Count only reps that meet your defined standard.
• Note the difference and gradually adjust your estimates.
• Do not make calibration a weekly requirement.

In bodybuilding, use RIR to manage stimulus and fatigue

To build muscle, a set generally needs to become hard, but not every set needs to reach failure. A range of about 1 to 3 RIR often works well for working sets: close enough to make the effort meaningful, with a buffer that can preserve technique and later performance. It is not the same optimum for every exercise or person.

On a machine or isolation exercise that is easy to stop, a final set at 0 or 1 RIR may be tolerable. On a squat, free-weight row, or exercise with a high whole-body fatigue cost, leaving more in reserve may produce a more recoverable workout. RIR helps individualize this decision; it does not prove how much you suffered.

The ACSM position stand published in 2026 states that momentary failure is unnecessary and presents 2–3 RIR as a practical way to reach sufficient effort, while judging the evidence insufficient to set one exact universal target. Meta-regressions also suggest that hypertrophy tends to increase as sets end closer to failure, but the precise shape of that relationship remains uncertain, particularly because RIR had to be estimated for many protocols. ACSM, 2026, Robinson et al., 2024

For an athletic physique, keep the useful lessons from bodybuilding: sufficiently hard sets, targeted muscles, measured progression, and recoverable volume. You do not need to adopt failure on every set, extreme volume, or contest preparation.

• Understand when muscular failure is useful or costly →
• Use RIR to measure comparable progress →

In powerlifting, RPE autoregulates the day's specific load

In powerlifting, a prescription such as “a single at RPE 8” lets you choose a challenging load with an estimated buffer instead of imposing the same percentage regardless of daily readiness. Subsequent sets can then be adjusted from that top set. The main benefit is maintaining the target effort while practicing the competition lifts.

RPE should not become permission to max out whenever you feel strong. Underestimating RPE on a heavy rep can quickly drive up both load and fatigue. Learn the technique, occasionally record the lift, use appropriate safety equipment, and compare your estimate with bar speed and subsequent performance.

If physique development is your main goal, borrow autoregulation and rigorous logging from powerlifting, not necessarily specialization in three lifts. Maximal strength and hypertrophy overlap, but they do not always require the same exercises, rep ranges, or fatigue costs.

In the gym and with bodyweight training, define the rep before the RIR

For general gym training, begin with a comfortable buffer, such as 2 to 4 RIR, while learning the movements. Once your technique is stable, bring selected sets closer to 1 to 3 RIR when your goal and recovery justify it. A moderate load performed consistently provides more useful information than a precise RPE on an exercise that changes every week.

RIR also works with push-ups, pull-ups, dips, single-leg squats, and other bodyweight exercises. Keep the same variation, range of motion, points of contact, and technical standard. Switching from strict push-ups to arched reps just to add a number does not represent a comparable reserve.

When an exercise becomes too easy, progress through reps, range of motion, leverage, stability, or added weight. On very long sets, accept a wider estimate: “3 to 5 RIR” may be more credible than “exactly 4.” Shortness of breath or muscle burn can cloud perception before you reach your actual muscular limit.

In gymnastics, session-RPE tracks overall load without measuring RIR for a skill

Researchers followed eight professional rhythmic gymnasts for 43 weeks using session-RPE and a recovery measure. They collected the rating after each workout to estimate its overall internal load. This use shows that RPE can apply to gymnastics, but it does not tie each skill to reps in reserve or make gymnastics the origin of RPE-RIR. Debien et al., 2020

A skill attempt depends on technique, coordination, confidence, and risk—not only muscular fatigue to failure. For gymnastics, skill-based calisthenics, or street workout, you might use session-RPE to monitor overall load and RIR for clearly defined strengthening sets. Do not convert a global workout rating into a fictitious number of skills remaining.

The word “gym” is ambiguous in French because it can mean either a fitness facility or gymnastics. In a weight room, set-based RPE-RIR applies directly to strength exercises. In competitive gymnastics, session-RPE and RIR address two separate needs.

Build a baseline over three sessions before adjusting your program

For three workouts, select two or three stable exercises. Record the load, reps, estimated RIR, equipment settings, and rest periods. Do not try to correct every variation yet. First determine whether your RPE 8 describes roughly the same effort from one exposure to the next.

For example, program three sets of cable rows for 8 to 12 reps at about 2 RIR. A workout logged as 12, 10, and 9 reps at 2 RIR provides a useful baseline. At the next workout, aim for one additional clean rep without changing the range of motion or deliberately taking every set closer to failure.

Calibrate one safe final set, then watch the trend. If you complete more reps at comparable load, technique, and RIR, the progression is credible. If performance declines on several exercises while effort rises, first review completed workouts, volume, recovery, and energy intake before adding work.

One high-RPE day does not diagnose a plateau. The rating becomes useful when it adds context to several comparable workouts. Then adjust one variable only: reps, load, sets, exercise, or recovery.

Tracking should reduce uncertainty, not make every rep a source of anxiety. If rating every set becomes overwhelming, limit RIR to your main working sets or use a simple range such as “1 to 3 RIR.”

• Diagnose a plateau before changing the entire program →
• Set the right number of hard sets per muscle →
• Choose when to train to muscular failure →