Rep max
Also known as: Repetition maximum, RM
A rep max, or repetition maximum (RM), is the greatest load a person can lift for a specified number of consecutive repetitions in a particular exercise under defined execution conditions. The number comes before RM: a 1RM is a maximum for one repetition, a 10RM is a maximum for ten, and a 5RM is a maximum for five.
The word "maximum" matters. If someone performs eight repetitions while deliberately leaving two reps in reserve, the weight is not an 8RM; it is simply a set of eight. An actual RM requires the next acceptable repetition to be unavailable under the stated technique standard. Because a true test is demanding and performance varies from day to day, many programs work with an approximate RM rather than testing every value directly.
Rep maxima are exercise-specific. A machine chest press RM cannot be transferred directly to a barbell bench press, and even two machines with the same weight label can have different mechanics. Range of motion, tempo, pauses, assistance, and equipment all affect the result. A useful record therefore stores more than the load and repetition count.
Coaches and programs use an RM to describe strength, prescribe a training load, or compare sets performed for different repetition counts. The relationship is not exact: two people with the same 1RM may have different 10RMs, and the same person may tolerate high repetitions better in one exercise than another. Percentage-based repetition charts are population estimates, not rules for every lifter.
When a formula converts a nonmaximal or differently sized set into another RM, label the output as estimated. An estimated 1RM, for example, is useful for trends and programming without a maximal single, but it is not interchangeable with a successfully tested 1RM. The distinction keeps both training records and claims about strength honest.