One-rep max1RM

Your one-rep max (1RM) is the heaviest load you can lift once with good form on a given exercise. It is the standard reference point for strength and for setting training loads as a percentage.

It matters because many programmes prescribe intensity as a percentage of 1RM, and it lets you compare strength over time or against standards. You rarely need to test it directly — it can be estimated from a set taken close to failure.

In practice, an estimated 1RM from a submaximal set (using a formula such as Epley or Brzycki) is safer and nearly as useful as a true max attempt.