Measurement
RIR (Reps in Reserve)
Also written: RIR, reps in reserve
How many more good reps you could have done when you stopped the set.
is the flip side of . If you stop with 2 good reps left in the tank, that’s 2 RIR (about RPE 8).
Most strength and muscle-building work happens between 1 and 4 RIR: hard, but not to failure every set.