RPE and RIR

Foundation · 12 min

RPE: grading your effort

RPE (rating of perceived exertion) is a scale on which you score how hard an effort feels to you, from 0 to 10. This programme uses the 0–10 version: 0 is complete rest; 2–3 is light effort, easy chatting; 4–6 is moderate effort — you can talk but not sing; 7–8 is hard, only a few words at a time; 9 is very hard, close to the limit; 10 is the most you could possibly do at that moment. The scale is subjective, and that is not a flaw: what it measures is precisely your own effort on the day. You may have noticed that the talk test from the first module is a rough shortcut for this scale. Hesitating between scores in your first attempts is natural; the “seven or eight?” debate rarely matters — what matters is scoring consistently with yourself.

RIR: how many reps in reserve?

RIR (reps in reserve) is a highly practical measure developed for strength sets: at the moment you end a set, how many more repetitions could you have done with proper technique? If the answer is “two more”, the set ended at 2 RIR; if “not one more would have come”, you were at 0 RIR. RIR estimates are rough at first, and that is normal; with a few weeks of experience they become markedly accurate. When a programme says “leave 2 RIR on the last set”, it is asking exactly this: end the set before exhaustion, with two reps in the tank. In the first weeks, make your estimate the moment the set ends, while the feeling is fresh; a few minutes later, memory tends to shrink the effort below what it was.

Two scales, one language

In strength work, RPE and RIR are two faces of the same fact, and they map roughly like this: RPE 10 means 0 RIR (nothing in reserve); RPE 9 about 1 RIR; RPE 8 about 2 RIR; RPE 7 about 3 RIR. The zone most often recommended for beginners is RPE 7–8 — that is, around 2–3 RIR: a clear challenge, with technique intact and a reserve in hand. This zone is the numerical form of the definition you met in the choosing resistance lesson: a clear challenge without form breakdown.

Why feel, and not a fixed weight?

The answer to “why doesn't the programme just print a weight?” is that the body is not a fixed machine. After a sleepless night or a heavy work day, the same dumbbell feels heavier; on a good day, lighter. A fixed weight target cannot see that fluctuation; RPE and RIR adjust automatically: if the target is “2 RIR”, that may mean fewer reps on a tired day and more on a good one. You neither force yourself on a bad day nor hold yourself back on a good one. The numbers are tools; the real skill is reading your own effort honestly, and that skill grows with every session. In time the reading becomes so natural that you barely think of the numbers at all; the scales are scaffolding, used until intuition settles in.