General
rir
What does rir mean?
Reps In Reserve: the number of additional reps you could have done before hitting failure on a set.
"Stop each set at about 2 RIR."
Origin
Strength-training autoregulation metric, closely tied to RPE.
Frequently asked questions
What does RIR mean?
RIR stands for Reps In Reserve — how many more reps you could have completed before reaching failure on a set.
What is a good RIR for muscle growth?
Many lifters aim for 1–3 reps in reserve on working sets, which keeps intensity high enough to stimulate growth while managing fatigue.
How do RIR and RPE relate?
They map directly onto each other: 2 RIR is about RPE 8, 1 RIR is RPE 9, and 0 RIR (failure) is RPE 10.
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