1RM (One-Repetition Maximum) is the heaviest weight an athlete can lift for one strict repetition of a given exercise. It's the canonical measure of maximum strength and the reference load most strength programs are prescribed against (e.g. "5×5 at 80% of 1RM").
Direct 1RM testing is high-stakes and fatiguing. For most non-elite athletes, a 3RM or 5RM is safer and converts to an estimated 1RM via Brzycki, Epley, or Lander formulas — typically within 5% of the true value. VBT load-velocity profiling produces another reliable estimate without going to failure.
Relative strength (1RM ÷ bodyweight) is often the more useful number: it normalizes across athlete size and correlates better with sprint and jump performance than absolute load.
Where it's used
Strength-training load prescription, athlete benchmarking, talent ID for strength-dependent sports.
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