How close to failure should you train?

Illustration for the guide: How close to failure should you train?

Short answer

End most sets with 1–3 repetitions in reserve (RIR). Closer to failure builds more muscle on average, but the last step all the way to failure adds little.

Figures

End most sets 1–3 reps short of failure
  • 0 reps in reserve (RIR): 0 RIR = failure: on average only a trivial advantage for growth (effect size 0.19)

How to estimate RIR

2 RIR means you could have done two more clean reps. The scale by Zourdos and colleagues introduced this measure to resistance training. Experienced lifters estimate more accurately than beginners.

Expect estimation error

Hughes and colleagues showed that accuracy varies by exercise. Many people misjudge at high rep counts. Now and then, test on the last set of a safe exercise how many reps you can really do.

Where failure fits

On machines and isolation exercises, a set is often easier to end under control. On squats and deadlifts, end the set when technique breaks. Log your honest estimate in SetCtl; an empty field stays empty.

Sources

  • Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions · Robinson · 2024 · Sports Medicine PubMed DOI Study note
  • Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis · Refalo; Martin C; Helms; Eric R; Trexler; Eric T; Hamilton; D. Lee; Fyfe; Jackson J · 2023 · Sports Medicine PubMed DOI Study note
  • Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve · Zourdos · 2016 · Journal of Strength and Conditioning Research PubMed
  • Estimating Repetitions in Reserve in Four Commonly Used Resistance Exercises · Hughes · 2020 · Journal of Strength and Conditioning Research PubMed
  • Effect of Training Leading to Repetition Failure on Muscular Strength: A Systematic Review and Meta-Analysis · Davies · 2016 · Sports Medicine PubMed

Summaries by SetCtl, not medical advice.