The most weight you can lift once with good form.
One-Repetition Maximum (1RM) is the heaviest load a person can lift once through a full range of motion with correct technique. It serves as an individualised benchmark of maximal dynamic strength for a given exercise, against which training loads are usually expressed as a percentage.
Knowing or estimating 1RM lets clinicians prescribe resistance exercise at a defined relative intensity rather than guessing an absolute weight, which matters for strength, hypertrophy or return-to-sport programming and for dosing safely around injury or post-surgical constraints. Serial 1RM (or estimated 1RM) values also give an objective marker of strength change over a rehabilitation episode, useful for justifying progression, discharge, or return-to-play decisions.
True 1RM is measured directly with a graded warm-up followed by progressively heavier single-attempt lifts until failure, typically taking several attempts and adequate rest between them. More commonly in clinical settings it is estimated from a submaximal set taken close to fatigue (e.g. a 5–10RM) using a repetition-to-failure prediction equation or chart, avoiding the fatigue and injury risk of true maximal testing.
Direct 1RM testing carries fatigue, technique-breakdown and injury risk, especially in deconditioned, older, or post-surgical patients, and is often inappropriate early in rehabilitation. Estimated 1RM from prediction equations introduces error that grows with the number of repetitions performed and varies by exercise and population, so it should be treated as an approximation rather than an exact figure, and comparisons over time are only meaningful if testing conditions and estimation method are kept consistent.
This guide was auto-drafted and is pending editorial review.