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Coach Sheet

Glossary entry — methodology

One-Rep Max 1RM

The maximum weight a lifter can perform for exactly one rep with proper form. The reference point against which all percentage-based prescriptions are calculated.

What 1RM means

1RM is the heaviest weight the lifter can complete for one rep with technically valid form. It’s the gold-standard reference for strength on a given lift and the anchor for percentage-based programming.

A 1RM is specific to:

  • A particular lift (squat 1RM ≠ deadlift 1RM ≠ bench 1RM)
  • A particular technique standard (raw vs equipped, paused vs touch-and-go)
  • A particular day (varies ±3-5% based on readiness)

Worked example

A lifter attempts a bench press 1RM. Warm-up sets at 60kg, 80kg, 100kg, 110kg. Then attempts:

  • 117.5 kg × 1 rep, completed cleanly (RPE 8.5, comfortable lockout)
  • 122.5 kg × 1 rep, completed with some grinding (RPE 9.5, slow lockout)
  • 127.5 kg × 1 rep, missed (couldn’t lock out)

The lifter’s 1RM is 122.5 kg. The 117.5 was sub-maximum (RPE 8.5 = 1-2 in reserve). The 127.5 was a missed attempt and doesn’t count.

1RM vs e1RM

1RM is what the lifter demonstrated. e1RM is what’s projected from a sub-maximal set using a formula. They aren’t equivalent:

  • A lifter’s e1RM at 119 kg with a measured 1RM at 122.5 kg has a 3 kg gap (within normal formula error)
  • An e1RM of 119 kg with a measured 1RM of 130 kg means the formulas underestimated, possibly because the lifter was conservative on RPE rating during the projection sets

Working coaches use e1RM as the day-to-day reference and confirm with measured 1RM during periodic testing.

When to test 1RM

Most lifters: at the end of a strength block, every 8-12 weeks. Powerlifters approaching a meet: 2-4 weeks out from competition.

Don’t test 1RM:

  • During a hypertrophy block (the goal isn’t 1RM expression)
  • Mid-mesocycle (interrupts the planned progression)
  • When fatigued from a hard week
  • For novice lifters whose form is still consolidating (use e1RM from working sets instead)

The three-test alternative

A single 1RM test has the variance issues described above. The three-test PR protocol takes three tests across 6-9 weeks at different rep ranges (5 RPE 8, 3 RPE 9, 1 RPE 9-10) and triangulates results. The output is a confidence band rather than a single number, which is more defensible for programming use.

How 1RM is used in programming

Once you have a 1RM (or e1RM), most percentage-based programs prescribe:

  • Top sets at 80-92% of 1RM (intensity work)
  • Backoff sets at 65-80% of 1RM (volume work)
  • Recovery work at 50-65% of 1RM (deloads)

The RPE calculator maps reps × RPE → percentage of 1RM, which lets you translate prescriptions like “5 reps at RPE 8” into target loads in kg.

Common mistakes

Treating 1RM as fixed. A lifter’s 1RM moves week to week. Weekly fluctuation is 3-5%. Quarterly trend is what matters; weekly readings are noise.

Testing too often. Every-month 1RM testing is excessive for most lifters. The neural and form-decay costs of frequent max attempts outweigh the data benefit.

Form drift on the test set. A 1RM that required a 30° lower-back rounding on the squat or a heel-rise on the deadlift isn’t a clean 1RM. Either invalidate the lift or attach a form caveat to the entry.

In Coach Sheet

The Lifting Records tab tracks 1RM and e1RM per main lift in separate columns. The 1RM column is updated manually on test days; the e1RM column updates automatically from working set logs. The Strength Progress chart displays both trends so a coach can spot when the projected and measured numbers diverge. Which usually signals either a calibration drift in RPE rating or genuine neural progress not reflected in working sets yet.

Sources

  1. [1]
  2. [2]