Training Explainer
What RIR Actually Means
RIR, or reps in reserve, is a simple idea that gets treated like a personality trait. Somewhere along the way it stopped being "how many more reps could I have done?" and started being something people argue about like it has a family crest.
It is neither complicated nor sacred. It is a number that answers one practical question: how hard was that set, really?
The actual definition
RIR is your estimate of how many more clean reps you could have completed with good form before failure. Finish a set of 8 and think you had 2 more in the tank? That is RIR 2. Finish a set and the weight is not moving again? That is RIR 0.
RPE is the same concept from the other direction. RPE 10 is roughly RIR 0. RPE 8 is roughly RIR 2. Different scale, same honest question underneath it.
The whole point of RIR is to stop you from guessing whether your weights are right. It is not a report card.
Where it earns its keep
RIR is most useful for deciding what to do next. If your target is RIR 2 and you hit RIR 4, the load was probably light. If you hit RIR 0 when the plan called for RIR 2, the next set probably needs a little respect. The bar gave you feedback. Listen to it.
The value compounds over weeks. A month of honest RIR estimates on your main lifts tells you more about whether you are progressing than one heroic set where the room got dramatic.
Where people overthink it
- Chasing fake precision. RIR 2 versus RIR 2.5 is not a meaningful distinction for most training decisions. It is a compass, not a ruler.
- Logging every warm-up like it has lore. Warm-ups usually do not need RIR. They are there to prepare you, not to create homework.
- Comparing it to other lifters. Two people's RIR 2 can mean very different things. Estimating effort is a skill, not a fixed unit.
A simple way to use it
Pick a target RIR before your working sets. After each set, make a fast, honest call. Let that nudge your next set's weight or your next session's plan. If it helps you make a better decision, log it. If it adds friction without adding insight, move on.
OpenSet logs RIR, to-failure work, rep style, and warm-ups as part of the set. The details are there when they matter, without turning a training session into a tax form.
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