One-repetition maximum (1RM)

The one-repetition maximum (1RM) is the greatest load that can be lifted through a full range of motion for a given exercise in a single maximal effort with proper form, serving as the gold-standard measure of maximal dynamic strength. Percentage-based training zones (e.g., 60–70% 1RM for hypertrophy, ≥85% 1RM for strength) are typically derived from the 1RM. Direct testing carries injury risk in untrained or older individuals; validated prediction equations (e.g., Epley, Brzycki) estimate 1RM from submaximal repetition-to-failure tests, though accuracy decreases above 5–10 reps. Progressive overload is operationalized as periodic 1RM increases over a training cycle; declining 1RM with age reflects both sarcopenia and dynapenia.