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Coach Sheet

Glossary entry — methodology

Reps in Reserve RIR

The number of reps a lifter could have done beyond what they did before reaching failure. RIR 2 = could have done 2 more.

What RIR means

RIR is the count of how many additional reps the lifter could have completed before missing one due to form breakdown or fatigue. It’s the inverse phrasing of RPE:

  • RIR 0 = true failure (RPE 10)
  • RIR 1 = one rep left (RPE 9)
  • RIR 2 = two reps left (RPE 8)
  • RIR 3 = three reps left (RPE 7)
  • RIR 4 = four reps left (RPE 6)

Both terms describe the same thing. RIR phrases it as a count, RPE phrases it as a feeling-rating.

Worked example

A lifter completes 100 kg × 6 reps and reports RIR 2. The interpretation:

  • The set ended at rep 6
  • Lifter could have continued to rep 8 with sound form
  • True maximum would have been 8 reps at 100 kg before hitting failure

Plugged into the RPE calculator as “8 effective reps at RPE 10 = 78.6% of 1RM”, the estimated 1RM is 100 / 0.786 = 127.2 kg.

Compare with the same lifter logging the same set as RIR 1 (only one rep in reserve): 7 effective reps × RPE 10 = 81.1%, estimated 1RM = 123.3 kg. The RIR difference of 1 rep moves the 1RM estimate by 4 kg.

When to use RIR over RPE

For new lifters, RIR is more concrete than RPE. “How many reps could you have done?” is a count question. “What was your RPE?” requires the lifter to have learned the 6-10 scale already.

For experienced lifters, the choice is stylistic. They’ve internalised the scale; either phrasing elicits the same answer.

When RIR breaks down

At low reps. Estimating “I could have done 1 more rep” on a 1RM attempt is conjecture. The lifter doesn’t know whether they had one more in the tank because they didn’t try. For 1-rep attempts, use RPE 9.5 or 10 directly rather than asking for RIR.

At high reps. Estimating “I could have done 4 more reps after rep 15” is similarly shaky. Past 10-12 reps, the lifter’s count gets noisy because cardiovascular fatigue overlays muscular fatigue. The RPE/RIR scale is most accurate in the 1-8 rep range.

On lifts with technical complexity. Olympic lifts (snatch, clean & jerk) often end on a missed rep due to technique rather than capacity. “I could have done 1 more” doesn’t apply when the miss was a balance issue, not a strength issue.

Common mistakes

Optimistic RIR. Some lifters habitually report RIR higher than reality (“I could have done 2 more”) because they want the prescription to scale up. This makes the program too aggressive. Watch for systematic overshoot in the lifter’s logs.

Pessimistic RIR. Some lifters undershoot (“RIR 4 felt safer to call than RIR 2”) because they don’t want the next session to be too heavy. Watch for systematic undershoot too.

Treating RIR like a target instead of a measurement. RIR is what happened on the set, not what was planned. If the program says “RIR 2” and the lifter ended at RIR 0, log RIR 0. The next prescription needs the honest data to adjust.

In Coach Sheet

The Workout Plan tab includes an optional RIR column for novice lifters. The 1RM calculator uses RIR alongside reps to compute effective rep count for the formula. The 3-test PR protocol prescribes specific RIR values for each test (5 reps RIR 2, 3 reps RIR 1, 1 rep RIR 0).

For most experienced lifters, we recommend using only RPE to keep the scale consistent. For new clients, ask for RIR alongside RPE for the first 4-8 weeks until the lifter is comfortable with the RPE scale alone.

Sources

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