Accuracy of Predicted Intraset Repetitions in Reserve (RIR) in Single- and Multi-Joint Resistance Exercises Among Trained and Untrained Men and Women.
Level 3 - non-randomized controlled study
Non-randomized repeated-measures laboratory trial graded by design analogy
PubMed 37036795 · doi:10.1177/00315125231169868
What was done
Fifty-eight participants (27 men, mean age 22 years, training experience 66 months; 31 women, mean age 20 years, training experience 22 months) completed a single testing session to assess intraset repetitions in reserve (RIR) prediction accuracy. After estimating 1RM from a 5RM test on biceps curls, triceps pushdowns, and seated rows, participants performed four sets of each exercise to momentary muscular failure at 72.5% of estimated 1RM in randomized order. Participants indicated when they first perceived 5 RIR and predicted RIR on every subsequent repetition until failure. Prediction accuracy was analyzed via 3-way repeated measures ANCOVA.
What was found
RIR prediction accuracy was significantly higher closer to failure and in later sets (p < 0.01 for both main effects). Exercise type did not significantly affect accuracy (p = 0.688). The 3-way interaction was not statistically significant (p = 0.435), and covariates of sex (p = 0.917), training experience (p = 0.462), and RIR rating experience (p = 0.462–0.917) did not significantly influence RIR difference values. Numerical prediction error values were not reported in the abstract.
Why it matters
This study shows that individuals estimate remaining repetitions more accurately as they approach muscular failure and in subsequent sets, independent of sex or prior training experience.
Limits
Evaluated only machine-based exercises at a single relative intensity (72.5% 1RM) in a young cohort. 1RM was estimated from a 5RM rather than directly tested, and absolute error magnitudes were omitted from the abstract.
Cited by
- context On average, beginner and intermediate lifters underestimate the number of repetitions they can achieve before failure by five to six repetitions.