Maximal Number of Repetitions at Percentages of the One Repetition Maximum: A Meta-Regression and Moderator Analysis of Sex, Age, Training Status, and Exercise

Abstract

The maximal number of repetitions that can be completed at various percentages of the one repetition maximum (1RM) [REPS ~ %1RM relationship] is foundational knowledge in resistance exercise programming. The current REPS ~ %1RM relationship is based on few studies and has not incorporated uncertainty into estimations or accounted for between-individuals variation. Therefore, we conducted a meta-regression to estimate the mean and between-individuals standard deviation of the number of repetitions that can be completed at various percentages of 1RM. We also explored if the REPS ~ %1RM relationship is moderated by sex, age, training status, and/or exercise. A total of 952 repetitions-to-failure tests, completed by 7289 individuals in 452 groups from 269 studies, were identified. Study groups were predominantly male (66%), healthy (97%), < 59 years of age (92%), and resistance trained (60%). The bench press (42%) and leg press (14%) were the most commonly studied exercises. The REPS ~ %1RM relationship for mean repetitions and standard deviation of repetitions were best described using natural cubic splines and a linear model, respectively, with mean and standard deviation for repetitions decreasing with increasing %1RM. More repetitions were evident in the leg press than bench press across the loading spectrum, thus separate REPS ~ %1RM tables were developed for these two exercises. Analysis of moderators suggested little influences of sex, age, or training status on the REPS ~ %1RM relationship, thus the general main model REPS ~ %1RM table can be applied to all individuals and to all exercises other than the bench press and leg press. More data are needed to develop REPS ~ %1RM tables for other exercises.

Fig. 1

Flow diagram of search strategy. RM repetition maximum

Fig. 2

Meta-analytic scatterplots from main models for both the natural cubic spline model used to model log mean repetitions (top left panel) and the linear model used to model standard deviation (SD) of repetitions (bottom left panel). Estimates from both models have been exponentiated back to the raw repetitions scale. For the mean repetitions plot, the dashed horizontal reference line is at one repetition. For the SD of the repetitions plot, the dashed horizontal reference line is at zero. The grey band shows the 95% confidence interval (CI) and the dashed lines show the 95% prediction interval. A table showing the exact point estimates and 95% CIs for both mean repetitions, and SDs of repetitions, is presented that ranges from 15 to 95% 1 repetition maximum (RM) at 5% 1RM intervals (right panel)

Fig. 3

Meta-analytic scatterplots for the bench press for both the natural cubic spline model used to model log mean repetitions (top left panel) and the linear model used to model standard deviation (SD) of repetitions (bottom left panel). Estimates from both models have been exponentiated back to the raw repetitions scale. For the mean repetitions plot, the dashed horizontal reference line is at one repetition. For the SD of repetitions plot, the dashed horizontal reference line is at zero. The grey band shows the 95% confidence interval (CI). A table showing the exact point estimates and 95% CIs for both mean repetitions, and SD of repetitions, is presented that ranges from 15 to 95% 1 repetition maximum (RM) at 5% 1RM intervals (right panel)

Fig. 4

Meta-analytic scatterplots for the leg press for both the natural cubic spline model used to model log mean repetitions (top left panel) and the linear model used to model standard deviation (SD) of repetitions (bottom left panel). Estimates for both models have been exponentiated back to the raw repetitions scale. For the mean repetitions plot, the dashed horizontal reference line is at one repetition. For the SD of repetitions plot, the dashed horizontal reference line is at zero. The grey band shows the 95% confidence interval (CI). A table showing the exact point estimates and 95% CIs for both mean repetitions, and SD of repetitions, is presented that ranges from 15 to 95% 1 repetition maximum (RM) at 5% 1RM intervals (right panel)