The one-rep max (1RM) is the heaviest weight you can lift for a single clean rep. It's the universal currency of strength — every program, percentage, and bragging right is denominated in it.
Testing your true 1RM is risky and exhausting, so lifters estimate it. The classic formula is Epley's: weight × (1 + reps ÷ 30). Benched 100 kg for 5? Your estimated 1RM is about 117 kg.
Why it matters: programs prescribe weights as percentages — "5×5 at 80%." Without knowing your 1RM, you're guessing. With it, every session has a target.
Don't max out every week
Estimates from submaximal sets are safer and, tracked over time, just as useful for programming. Save true max attempts for rare test days.
Yuki's takeaway
Your 1RM isn't a trophy. It's a compass — it tells every workout where to go.