Meta-analysis — 2024 — Strength · Repetitions & load
Maximal Number of Repetitions at Percentages of the One Repetition Maximum: A Meta-Regression and Moderator Analysis of Sex, Age, Training Status, and Exercise
What did the researchers investigate?
The maximal reps people can complete at different percentages of 1RM, and how much this varies between people, from 952 tests in 269 studies.
What did they find?
Mean reps and their spread both fall as %1RM rises. More reps were possible on the leg press than the bench press, so separate tables were produced for those. Sex, age and training status had little influence.
What does this mean for training?
Reps at a given %1RM vary between people and exercises, so any reps-to-1RM conversion is an estimate with uncertainty.
How does FitX AI use this evidence?
FitX AI treats estimated 1RM as an estimate: it updates from your own logged sets and is cautious with heavy low-rep sets.
Where FitX AI's own choices go beyond this paper
Estimated 1RM. Estimates are approximate; they vary by exercise and person.
Careful heavy-set estimate. Taking the median of four formulas is an engineering choice, not a validated method.
Limitations
Most data came from the bench press and leg press; the authors note more data are needed for other exercises.