Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
Your one-rep max is the heaviest load you can lift once with good form. It's the reference point for strength programming, since training plans are usually written as a percentage of 1RM (e.g. 5 sets of 5 at 80%). Rather than testing a true max, which is risky, most lifters estimate it from a sub-maximal set using formulas like Epley or Brzycki, which are accurate up to about 10 reps.
- Heaviest weight for a single rep
- Basis for percentage-based training
- Estimated from sub-max sets (Epley, Brzycki)
- Most accurate from sets of 3-6 reps
In practice
A true one-rep max (the absolute heaviest weight liftable for a single rep with correct form) is often estimated rather than directly tested for safety and practicality — submaximal-rep formulas let lifters estimate their 1RM from a lighter, higher-rep set, which is useful for programming percentage-based training without the fatigue and injury risk of frequent true maximal attempts.
FAQ
How often should I test my true one-rep max?
Most coaches recommend testing a true 1RM only occasionally (every several months), relying on submaximal-rep estimates for regular programming to reduce fatigue and injury risk from frequent maximal attempts.
Why do coaches prefer estimating 1RM over testing it directly?
Submaximal testing (e.g. a set of 5 reps) carries lower injury risk and technical breakdown risk than a true maximal single, while still giving a reasonably accurate percentage-based training reference.