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RPE and RIR Training: How Autoregulation Works
How to use RPE and reps in reserve to autoregulate lifting loads: the RIR scale, what research shows, RPE charts by percentage and a sample week.
A percentage of 1RM tells you what a lift weighed on your best day. Rating of perceived exertion (RPE) tells you what the lift costs today. Autoregulation uses that daily reading to adjust load and volume. This article explains the RIR-based RPE scale, the evidence, and how to program with it.
The RIR-based RPE scale
Resistance training RPE is anchored to repetitions in reserve (RIR). RIR is the number of reps you could still have done with good form at the end of a set.
| RPE | Meaning | RIR |
|---|---|---|
| 10 | Maximal, no reps left | 0 |
| 9.5 | No more reps, could add slight load | 0 to 1 |
| 9 | One more rep possible | 1 |
| 8 | Two more reps possible | 2 |
| 7 | Three more reps possible | 3 |
| 6 or less | Four or more reps left, speed work | 4+ |
The scale was validated by Zourdos and colleagues in a 2016 study of experienced and novice squatters. Lifters rated singles at 60%, 75% and 90% of 1RM and an 8-rep set at 70% of 1RM. RPE correlated strongly and inversely with bar velocity in experienced squatters (r = -0.88).
"The RIR-based RPE scale is a practical method to regulate daily training load and provide feedback during a 1RM test."
Zourdos and colleagues, Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve, Journal of Strength and Conditioning Research, 2016
Why autoregulate at all?
Your true 1RM moves day to day with sleep, stress, nutrition and accumulated fatigue. A fixed percentage can be too heavy on a bad day and too light on a good one. RPE lets the prescription follow your readiness.
The evidence is supportive, if mixed. A 2022 meta-analysis of 15 studies found autoregulated and percentage-based load prescription produced similar strength gains in trained lifters. For volume autoregulation, velocity loss thresholds of 25% or less favored strength, while thresholds above 20 to 25% favored hypertrophy.
A 2021 meta-analysis of eight studies in 166 athletes reported that autoregulation outperformed fixed loading for maximal strength (ES 0.64). The two analyses differ in populations and methods. The fair summary is that autoregulation is at least as effective as percentages, and easier to individualize.
Load autoregulation vs volume autoregulation
Autoregulation can adjust two things.
Load: top set at a target RPE
Prescribe a rep target and an RPE, for example "squat 1 x 3 at RPE 8." Work up until three reps leave about two in the tank. That weight is today's top set.
Volume: back-off sets or fatigue percentage
After the top set, prescribe back-off work by RPE or by a load drop. Two common methods:
- RPE stop: "4 x 3 at RPE 8, stop adding sets when a set reaches RPE 9."
- Load drop: "top single at RPE 8, then 3 x 5 at 85% of the top single."
Volume autoregulation is powerful but easy to overdo. Cap the number of back-off sets.
Converting RPE to percentages
Coaches often combine RPE and percentages. The table below shows rounded values from the widely used Tuchscherer-style RPE chart. Treat them as starting points, because individual values vary by lift and lifter.
| Reps | RPE 7 | RPE 8 | RPE 9 | RPE 10 |
|---|---|---|---|---|
| 1 | ~89% | ~92% | ~96% | 100% |
| 3 | ~84% | ~86% | ~89% | ~92% |
| 5 | ~79% | ~81% | ~84% | ~86% |
| 8 | ~71% | ~74% | ~76% | ~79% |
Use the chart to set an expected range. If the prescribed RPE arrives far below or above that range, trust the bar, log it and adjust next week.
A sample autoregulated week
This upper/lower week uses RPE for the main lifts and RIR for accessories. Accumulation weeks sit at RPE 7 to 8. Intensification weeks move to RPE 8 to 9.
| Day | Main lift | Prescription | Accessories |
|---|---|---|---|
| Monday | Squat | 1 x 4 at RPE 8, then 3 x 4 at 90% of top set | 3 sets, 2 RIR |
| Tuesday | Bench press | 1 x 5 at RPE 8, then 4 x 5 at 88% | 3 sets, 1 to 2 RIR |
| Thursday | Deadlift | 1 x 3 at RPE 8, then 2 x 3 at 90% | 2 to 3 sets, 2 RIR |
| Friday | Overhead press | 4 x 6 at RPE 7 to 8 | 3 sets, 1 RIR |
Across a mesocycle, raise the RPE target by about half a point every 1 to 2 weeks. Finish with a lighter week at RPE 6 to 7 before the next block.
Getting accurate ratings
RPE is a skill. Novices tend to underestimate how many reps they have left, especially on high-rep sets. Accuracy improves as sets get closer to failure.
- Rate every work set immediately after you rack the bar.
- Test your ratings every few weeks: take one planned RPE 8 set to an actual rep max and compare.
- Use RPE for main lifts and RIR targets for accessories, so the language stays simple.
- Keep percentage guardrails for newer lifters, for example "RPE 8, but no more than 82% 1RM."
Build it in the free builder
Open the free program builder and enable RPE prescriptions. Enter your recent rep maxes, training days and goal, and the builder writes each main lift as a top set at a target RPE with back-off work.
Want a working example first? Open the starter programs and choose an RPE-based block to inspect week by week.