# RIR (Reps in Reserve)

Reps in Reserve (RIR) is an autoregulation method for setting and grading how hard you train with weights. You estimate, at the end of a set, how many more reps you could have done before hitting failure. An RIR of 0 means a maximal effort (an RPE of 10 on a 0-to-10 scale). RIR 1 means you stopped one rep short of failure. RIR 3 means three reps in reserve. Zourdos and colleagues validated it (J Strength Cond Res, 2016). The RIR-based RPE scale correlates strongly with bar speed and with your percentage of 1-rep maximum (1RM), in both experienced and novice lifters. The correlation is tighter at higher intensities. Compared with rigid '%1RM' plans, RIR adapts to how ready you feel that day. That is why modern muscle-building and powerlifting programs favor it.

## Sources

- Zourdos MC, Klemp A, Dolan C, et al.. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research. https://doi.org/10.1519/JSC.0000000000001049
- Helms ER, Cronin J, Storey A, Zourdos MC. (2016). Application of the Repetitions in Reserve-Based Rating of Perceived Exertion Scale for Resistance Training. Strength and Conditioning Journal. https://doi.org/10.1519/SSC.0000000000000218
- Bastos V, Machado S, Teixeira DS. (2024). Feasibility and Usefulness of Repetitions-In-Reserve Scales for Selecting Exercise Intensity: A Scoping Review. Perceptual and Motor Skills. https://doi.org/10.1177/00315125241241785

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