RPE vs reps in reserve

First identify which RPE scale you mean

RPE means rating of perceived exertion, but that phrase does not identify a single scale. This guide uses the resistance-training, RIR-based set scale investigated by Zourdos and colleagues. It should not be mixed with Borg's 6–20 scale or a whole-session rating. Put the scale name in your log template once so future entries have a consistent meaning.

On this scale, the score describes an estimate of proximity to the end of a set. It does not directly describe percentage of 1RM, discomfort or how long the whole workout lasted. Two lifters can use the same load for five reps and report different ratings. That does not make either rating a universal strength benchmark.

Sources: Zourdos et al. (2016): resistance-training RPE measuring RIR; Helms et al. (2016): applying the RIR-based RPE scale

The common mapping near the end of a set

The arithmetic relationship in these entries is RPE = 10 minus estimated RIR. For example, a set rated two reps in reserve is RPE 8 on this scale. The arithmetic converts labels; it cannot verify that two reps were truly available. There is no need to chase a failed rep to complete the table.

When a set feels comfortably far from a limit, a broad note such as several reps left may be more honest than an elaborate decimal. Use the detail your program needs without inventing certainty.

Sources: Zourdos et al. (2016): resistance-training RPE measuring RIR

Define what another rep would have looked like

For a useful training log, judge reserve against the same execution standard as the completed reps. If your bench set used a pause, another fast touch-and-go rep answers a different question. If you would need assistance or a substantially different range of motion, do not count that imagined rep as equivalent to the set you recorded.

This is a practical logging convention, not a claim that subjective ratings can identify the precise point of technical failure. Record observable changes separately: pause shortened, depth uncertain, setup changed or spotter touched bar. The effort score should not conceal those details, and a technically questionable rep does not become valid because you rated the set RPE 8.

Why the estimate deserves some uncertainty

Research does not establish perfect rep prediction. Steele and colleagues found imperfect predictions in a study that asked participants to forecast reps before a set, with a tendency toward better accuracy with experience. That design differs from rating reserve immediately after a set, so its errors should not be pasted onto every individual RIR entry.

The practical lesson is to avoid treating a rating as an exact contract. You can write RIR about 2, uncertain instead of revising the number afterward to justify an increase. Experience may help your judgment, but it does not remove ambiguity. A video can help assess execution; it cannot reveal with certainty how many future reps your body could have completed.

Sources: Steele et al. (2017): limits of predicting repetitions

Read a short log without overclaiming

The ratings communicate decreasing estimated reserve even though load and reps are unchanged. Later set position and a shorter final break give the scores context. Do not call the third set lost strength compared with the first; the lifter has already performed more work. On the next exposure, compare first set with first set rather than selecting whichever score supports the conclusion you hoped to see.

Use the score inside a decision rule

If your program specifies an effort range, use its instructions for selecting or adjusting loads. A target of RPE 8 is not an instruction to keep adding weight until every set is hard. Record the first set honestly, then apply the plan's allowed adjustment. If technique or control changes, address that observation rather than forcing a rating target.

For tracking alone, you can keep the load unchanged while learning to describe effort. Write the score soon after the set, before looking at last week's rating, to reduce the temptation to make the trend look tidy. Also record set order and rest; a fifth set and a fresh first set are different observations.

Build a consistent habit, not a second competition

Pick one exercise you already perform and add an effort field to its normal entries. Keep completed reps, actual total bar load, variation, rest and a short execution note. After several exposures, review whether the same task became easier or whether more load was handled at similar reported effort. Do not award yourself progress just for choosing a lower score.

If you want to measure progress without frequent maximal attempts, comparable submaximal sets can provide useful signals. The website's guides are available now, and joining the upcoming app's waitlist is optional. An effort rating belongs in a training record; a completed PR total still requires completed lifts.

• Measure strength using comparable sets
• Choose a rep-range progression rule

Sources and scope

These references support the specific factual points cited above. The examples and decision aids are original illustrations, not individualized coaching or medical advice.

• Zourdos et al. (2016): resistance-training RPE measuring RIR

  Primary squat study, January 2016; abstract checked October 6, 2026. Supports the RIR-based set-RPE mapping. It is not an exact individual 1RM prediction table.

• Steele et al. (2017): limits of predicting repetitions

  Author's university record and abstract checked October 6, 2026; PeerJ 5:e4105. Participants predicted reps before single sets. Supports caution about prediction accuracy, not a prescribed error margin for post-set RIR.

• Helms et al. (2016): applying the RIR-based RPE scale

  Strength and Conditioning Journal article checked October 6, 2026. Supports distinguishing the original Borg 6–20 scale from RIR-based resistance-training ratings; used for terminology, not superiority claims.