One-rep max (1RM)
A one-rep max (1RM) is the heaviest weight you can lift for one full repetition of an exercise with good form. It's the standard measure of maximal strength, and many programs set training weights as a percentage of it, like 3 × 5 at 80% of 1RM.
There are two ways to find your one-rep max. You can test it by working up to the heaviest single you can complete. Or you can estimate it from a heavier set of a few reps, using a formula.
A tested max is the more accurate number, and it's a consistent one. A systematic review found the 1RM test gives very similar results from one session to the next, even in untrained people and even without a practice session first (Grgic 2020). The cost is fatigue: a max attempt takes a whole session, needs a spotter or safety pins, and one bad day skews it. That's why most lifters test rarely and estimate the rest of the time.
A common protocol, using a 100 kg target as the example:
Test squats and bench presses with safety pins set or a spotter behind you.
An estimate uses a set taken to failure, or close to it. The two most common formulas are Epley's (Epley 1985) and Brzycki's (Brzycki 1993):
| Set | Epley | Brzycki |
|---|---|---|
| 100 kg × 3 | 110 kg | 106 kg |
| 100 kg × 5 | 117 kg | 113 kg |
| 100 kg × 10 | 133 kg | 133 kg |
Epley gives a higher number than Brzycki at low reps, and the two meet at 10. Neither is “right”. What matters is using the same one every time, so your estimates stay comparable.
Close enough to train with, as long as the set was heavy. A study of seven formulas found every estimate tracked the lifters' real maxes closely. But most still ran consistently high or low on the bench press and squat, and every formula underestimated the deadlift (LeSuer 1997). Another study found estimates were most accurate from a 5-rep max and got worse from 10- and 20-rep maxes (Reynolds 2006).
In practice: estimate from sets of about 3–6 reps taken close to failure, and treat anything estimated from 10 or more reps as a rough guide. Even if the number is a few kilos off your true max, the trend over weeks is still real.
Sweatora never asks you to test a max. Every set you log gets an Epley estimate from its weight and the reps you did. A logged single counts as itself, since Epley would put it about 3% higher. Each exercise's stats screen shows your estimated 1RM, taken from your best set in your most recent session, so it moves as you get stronger.
RPE
RPE (rate of perceived exertion) is a 1–10 rating of how hard a set was. In lifting, it's scored by how many more reps you could have done: RPE 10 means none, RPE 9 means one, and RPE 8 means two. It lets you record and plan effort, not just weight.
RIR
RIR (reps in reserve) is the number of extra reps you could have done at the end of a set, with good form, before reaching failure. A set of 8 that you could have taken to 10 is “8 reps at 2 RIR”. It's a simple way to measure and plan how close to failure you train.
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