RPE and Reps in Reserve: Useful Estimates, Not Exact Measurements

Oct 3, 2023

2 min read

Updated: 23 hours ago

RPE describes perceived effort. Reps in reserve, or RIR, estimates how many additional repetitions you could have completed under the same conditions. Both can make a training log more informative.

Define the scale

Several RPE scales exist. In a resistance-training RIR-based scale, an estimate of no repetitions remaining differs from stopping with several available. Make sure coach and athlete mean the same thing before using a number to guide the programme.

Record the task as well as the effort

Write down load, repetitions, range and any relevant change in execution. An RIR estimate becomes less useful if you would need a different movement to complete the supposed remaining repetitions.

Expect uncertainty

These are estimates, especially with unfamiliar exercises or loads. Experience and clear definitions can improve their usefulness, but a score does not become an objective test simply because it is written as a number.

Use it to inform a decision

For example, if a planned set feels much harder than expected, you may repeat the load or reduce the next demand rather than automatically progress. That is a coaching choice, not a diagnosis of fatigue or an injury-prevention guarantee.

Use the scale to support a conversation about the work. It should make the programme more adaptable, not add another number you feel compelled to perfect.